Patent Application
20230027888
The entire disclosure of Japanese Patent Application No. 2021-106074, filed Jun. 25, 2021 is expressly incorporated by reference herein.
The present invention relates to an organic electroluminescence device, an organic electroluminescence display device, an electronic device, and a compound.
When voltage is applied to an organic electroluminescence device (hereinafter, occasionally referred to as an organic EL device), holes are injected from an anode and electrons are injected from a cathode into an emitting layer. The injected holes and electrons are recombined in the emitting layer to form excitons. Specifically, according to the electron spin statistics theory, singlet excitons and triplet excitons are generated at a ratio of 25%:75%.
A fluorescent organic EL device using light emission from singlet excitons has been applied to a full-color display such as a mobile phone and a television set, but an internal quantum efficiency is said to be at a limit of 25%. Studies have thus been made to improve performance of the organic EL device.
For instance, the organic EL device is expected to emit light more efficiently using triplet excitons in addition to singlet excitons. In view of the above, a highly-efficient fluorescent organic EL device using thermally activated delayed fluorescence (hereinafter simply referred to as “delayed fluorescence” in some cases) has been proposed and studied.
A Thermally Activated Delayed Fluorescence (TADF) mechanism uses such a phenomenon that inverse intersystem crossing from triplet excitons to singlet excitons thermally occurs when a material having a small energy difference (ΔST) between singlet energy level and triplet energy level is used. Thermally activated delayed fluorescence is explained in “Yuki Hando-tai no Debaisu Bussei (Device Physics of Organic Semiconductors)” (edited by ADACHI Chihaya, published by Kodansha, issued on Apr. 1, 2012, on pages 261-268).
For instance, Literatures 1, 2, and 3 describe an organic electroluminescence device using a delayed fluorescent compound.
In order to improve performance of an electronic device such as a display, there is a demand for further improvement in performance of an organic electroluminescence device.
An object of the invention is to provide an organic electroluminescence device and an organic electroluminescence display device capable of achieving higher performance (especially, a decrease in voltage), specifically, both luminous efficiency and voltage suitable for practical use, an electronic device including the organic electroluminescence device, and an electronic device including the organic electroluminescence display device.
Another object of the invention is to provide a compound with which an organic electroluminescence device, an organic electroluminescence display device, and an electronic device can achieve higher performance (especially, a decrease in voltage), specifically, both luminous efficiency and voltage suitable for practical use. According to an aspect of the invention, there is provided an organic electroluminescence device, including: an anode; a cathode; an emitting layer provided between the anode and the cathode; a first layer provided between the anode and the emitting layer; and a second layer provided between the anode and the first layer, in which the emitting layer contains a delayed fluorescent compound; the first layer contains a first compound; the second layer contains a second compound; an ionization potential Ip(HT1) of the first compound satisfies a numerical formula (Numerical Formula 1) below; a hole mobility μh(HT1) of the first compound satisfies a numerical formula (Numerical Formula 2) below; an ionization potential Ip(HT2) of the second compound satisfies a numerical formula (Numerical Formula 3) below; and the first layer has a film thickness of 15 nm or more.
Ip(HT1)≥5.69 eV (Numerical Formula 1)
μh(HT1)≥1.00×10−5 cm2/Vs (Numerical Formula 2)
Ip(HT2)≥5.60 eV (Numerical Formula 3)
According to another aspect of the invention, there is provided an electronic device including the organic electroluminescence device according to the above aspect of the invention.
According to still another aspect of the invention, there is provided an organic electroluminescence display device, including: an anode and a cathode arranged to face each other; a blue-emitting organic EL device as a blue pixel; a green-emitting organic EL device as a green pixel; and a red-emitting organic EL device as a red pixel, in which the red pixel includes the organic electroluminescence device according to the aspect of the invention as the red-emitting organic EL device; the red-emitting organic EL device includes: a red emitting layer as the emitting layer; the first layer provided between the red emitting layer and the anode; and the second layer provided between the first layer and the anode; the blue-emitting organic EL device includes a blue emitting layer provided between the anode and the cathode; the green-emitting organic EL device includes a green emitting layer provided between the anode and the cathode; and the second layer is provided between the anode and each of the blue emitting layer, the green emitting layer, and the first layer in a shared manner across the blue-emitting organic EL device, the green-emitting organic EL device, and the red-emitting organic EL device.
According to a further aspect of the invention, there is provided an electronic device including the organic electroluminescence display device according to the above aspect of the invention.
According to a still further aspect of the invention, there is provided a compound represented by a formula (10) below.
In the formula (10):
L10 is a single bond, or a substituted or unsubstituted arylene group having 6 to 12 ring carbon atoms;
a substituent, if present, for L10 is an unsubstituted phenyl group;
Ar10 is a substituted or unsubstituted aryl group having 6 to 18 ring carbon atoms; and
a substituent, if present, for Ar10 is an unsubstituted phenyl group or an unsubstituted naphthyl group.
According to the aspects of the invention, there are provided an organic electroluminescence device and an organic electroluminescence display device capable of achieving higher performance (especially, a decrease in voltage), specifically, both luminous efficiency and voltage suitable for practical use, an electronic device including the organic electroluminescence device, and an electronic device including the organic electroluminescence display device.
According to the aspect of the invention, there is provided a compound with which an organic electroluminescence device, an organic electroluminescence display device, and an electronic device can achieve higher performance (especially, a decrease in voltage), specifically, both luminous efficiency and voltage suitable for practical use.
Herein, a hydrogen atom includes isotope having different numbers of neutrons, specifically, protium, deuterium and tritium.
In chemical formulae herein, it is assumed that a hydrogen atom (i.e. protium, deuterium and tritium) is bonded to each of bondable positions that are not annexed with signs “R” or the like or “D” representing a deuterium.
Herein, the ring carbon atoms refer to the number of carbon atoms among atoms forming a ring of a compound (e.g., a monocyclic compound, fused-ring compound, cross-linking compound, carbon ring compound, and heterocyclic compound) in which the atoms are bonded to each other to form the ring. When the ring is substituted by a substituent(s), carbon atom(s) contained in the substituent(s) is not counted in the ring carbon atoms. Unless otherwise specified, the same applies to the “ring carbon atoms” described later. For instance, a benzene ring has 6 ring carbon atoms, a naphthalene ring has 10 ring carbon atoms, a pyridine ring has 5 ring carbon atoms, and a furan ring has 4 ring carbon atoms. Further, for instance, 9,9-diphenylfluorenyl group has 13 ring carbon atoms and 9,9′-spirobifluorenyl group has 25 ring carbon atoms.
When a benzene ring is substituted by a substituent in a form of, for instance, an alkyl group, the number of carbon atoms of the alkyl group is not counted in the number of the ring carbon atoms of the benzene ring. Accordingly, the benzene ring substituted by an alkyl group has 6 ring carbon atoms. When a naphthalene ring is substituted by a substituent in a form of, for instance, an alkyl group, the number of carbon atoms of the alkyl group is not counted in the number of the ring carbon atoms of the naphthalene ring. Accordingly, the naphthalene ring substituted by an alkyl group has 10 ring carbon atoms.
Herein, the ring atoms refer to the number of atoms forming a ring of a compound (e.g., a monocyclic compound, fused-ring compound, cross-linking compound, carbon ring compound, and heterocyclic compound) in which the atoms are bonded to each other to form the ring (e.g., monocyclic ring, fused ring, and ring assembly). Atom(s) not forming the ring (e.g., hydrogen atom(s) for saturating the valence of the atom which forms the ring) and atom(s) in a substituent by which the ring is substituted are not counted as the ring atoms. Unless otherwise specified, the same applies to the “ring atoms” described later. For instance, a pyridine ring has 6 ring atoms, a quinazoline ring has 10 ring atoms, and a furan ring has 5 ring atoms. For instance, the number of hydrogen atom(s) bonded to a pyridine ring or the number of atoms forming a substituent are not counted as the pyridine ring atoms. Accordingly, a pyridine ring bonded to a hydrogen atom(s) or a substituent(s) has 6 ring atoms. For instance, the hydrogen atom(s) bonded to carbon atom(s) of a quinazoline ring or the atoms forming a substituent are not counted as the quinazoline ring atoms. Accordingly, a quinazoline ring bonded to hydrogen atom(s) or a substituent(s) has 10 ring atoms.
Herein, “XX to YY carbon atoms” in the description of “substituted or unsubstituted ZZ group having XX to YY carbon atoms” represent carbon atoms of an unsubstituted ZZ group and do not include carbon atoms of a substituent(s) of the substituted ZZ group. Herein, “YY” is larger than “XX,” “XX” representing an integer of 1 or more and “YY” representing an integer of 2 or more.
Herein, “XX to YY atoms” in the description of “substituted or unsubstituted ZZ group having XX to YY atoms” represent atoms of an unsubstituted ZZ group and does not include atoms of a substituent(s) of the substituted ZZ group. Herein, “YY” is larger than “XX,” “XX” representing an integer of 1 or more and “YY” representing an integer of 2 or more.
Herein, an unsubstituted ZZ group refers to an “unsubstituted ZZ group” in a “substituted or unsubstituted ZZ group,” and a substituted ZZ group refers to a “substituted ZZ group” in a “substituted or unsubstituted ZZ group.”
Herein, the term “unsubstituted” used in a “substituted or unsubstituted ZZ group” means that a hydrogen atom(s) in the ZZ group is not substituted with a substituent(s). The hydrogen atom(s) in the “unsubstituted ZZ group” is protium, deuterium, or tritium.
Herein, the term “substituted” used in a “substituted or unsubstituted ZZ group” means that at least one hydrogen atom in the ZZ group is substituted with a substituent. Similarly, the term “substituted” used in a “BB group substituted by AA group” means that at least one hydrogen atom in the BB group is substituted with the AA group.
Substituents mentioned herein will be described below.
An “unsubstituted aryl group” mentioned herein has, unless otherwise specified herein, 6 to 50, preferably 6 to 30, more preferably 6 to 18 ring carbon atoms.
An “unsubstituted heterocyclic group” mentioned herein has, unless otherwise specified herein, 5 to 50, preferably 5 to 30, more preferably 5 to 18 ring atoms.
An “unsubstituted alkyl group” mentioned herein has, unless otherwise specified herein, 1 to 50, preferably 1 to 20, more preferably 1 to 6 carbon atoms.
An “unsubstituted alkenyl group” mentioned herein has, unless otherwise specified herein, 2 to 50, preferably 2 to 20, more preferably 2 to 6 carbon atoms.
An “unsubstituted alkynyl group” mentioned herein has, unless otherwise specified herein, 2 to 50, preferably 2 to 20, more preferably 2 to 6 carbon atoms.
An “unsubstituted cycloalkyl group” mentioned herein has, unless otherwise specified herein, 3 to 50, preferably 3 to 20, more preferably 3 to 6 ring carbon atoms.
An “unsubstituted arylene group” mentioned herein has, unless otherwise specified herein, 6 to 50, preferably 6 to 30, more preferably 6 to 18 ring carbon atoms.
An “unsubstituted divalent heterocyclic group” mentioned herein has, unless otherwise specified herein, 5 to 50, preferably 5 to 30, more preferably 5 to 18 ring atoms.
An “unsubstituted alkylene group” mentioned herein has, unless otherwise specified herein, 1 to 50, preferably 1 to 20, more preferably 1 to 6 carbon atoms.
Specific examples (specific example group G1) of the “substituted or unsubstituted aryl group” mentioned herein include unsubstituted aryl groups (specific example group G1A) below and substituted aryl groups (specific example group G1B). Herein, an unsubstituted aryl group refers to an “unsubstituted aryl group” in a “substituted or unsubstituted aryl group,” and a substituted aryl group refers to a “substituted aryl group” in a “substituted or unsubstituted aryl group.” A simply termed “aryl group” herein includes both of an “unsubstituted aryl group” and a “substituted aryl group.”
The “substituted aryl group” refers to a group derived by substituting at least one hydrogen atom in an “unsubstituted aryl group” with a substituent. Examples of the “substituted aryl group” include a group derived by substituting at least one hydrogen atom in the “unsubstituted aryl group” in the specific example group G1A below with a substituent, and examples of the substituted aryl group in the specific example group G1B below. It should be noted that the examples of the “unsubstituted aryl group” and the “substituted aryl group” mentioned herein are merely exemplary, and the “substituted aryl group” mentioned herein includes a group derived by further substituting a hydrogen atom bonded to a carbon atom of a skeleton of a “substituted aryl group” in the specific example group G1B below, and a group derived by further substituting a hydrogen atom of a substituent of the “substituted aryl group” in the specific example group G1B below.
phenyl group, p-biphenyl group, m-biphenyl group, o-biphenyl group, p-terphenyl-4-yl group, p-terphenyl-3-yl group, p-terphenyl-2-yl group, m-terphenyl-4-yl group, m-terphenyl-3-yl group, m-terphenyl-2-yl group, o-terphenyl-4-yl group, o-terphenyl-3-yl group, o-terphenyl-2-yl group, 1-naphthyl group, 2-naphthyl group, anthryl group, benzanthryl group, phenanthryl group, benzophenanthryl group, phenalenyl group, pyrenyl group, chrysenyl group, benzochrysenyl group, triphenylenyl group, benzotriphenylenyl group, tetracenyl group, pentacenyl group, fluorenyl group, 9,9′-spirobifluorenyl group, benzofluorenyl group, dibenzofluorenyl group, fluoranthenyl group, benzofluoranthenyl group, perylenyl group, and a monovalent aryl group derived by removing one hydrogen atom from cyclic structures represented by formulae (TEMP-1) to (TEMP-15) below.
o-tolyl group, m-tolyl group, p-tolyl group, para-xylyl group, meta-xylyl group, ortho-xylyl group, para-isopropylphenyl group, meta-isopropylphenyl group, ortho-isopropylphenyl group, para-t-butylphenyl group, meta-t-butylphenyl group, ortho-t-butylphenyl group, 3,4,5-trimethylphenyl group, 9,9-dimethylfluorenyl group, 9,9-diphenylfluorenyl group, 9,9-bis(4-methylphenyl)fluorenyl group, 9,9-bis(4-isopropylphenyl)fluorenyl group, 9,9-bis(4-t-butylphenyl)fluorenyl group, cyanophenyl group, triphenylsilylphenyl group, trimethylsilylphenyl group, phenylnaphthyl group, naphthylphenyl group, and a group derived by substituting at least one hydrogen atom of a monovalent group derived from one of the cyclic structures represented by the formulae (TEMP-1) to (TEMP-15) with a substituent.
The “heterocyclic group” mentioned herein refers to a cyclic group having at least one hetero atom in the ring atoms. Specific examples of the hetero atom include a nitrogen atom, oxygen atom, sulfur atom, silicon atom, phosphorus atom, and boron atom.
The “heterocyclic group” mentioned herein is a monocyclic group or a fused-ring group.
The “heterocyclic group” mentioned herein is an aromatic heterocyclic group or a non-aromatic heterocyclic group.
Specific examples (specific example group G2) of the “substituted or unsubstituted heterocyclic group” mentioned herein include unsubstituted heterocyclic groups (specific example group G2A) and substituted heterocyclic groups (specific example group G2B). Herein, an unsubstituted heterocyclic group refers to an “unsubstituted heterocyclic group” in a “substituted or unsubstituted heterocyclic group,” and a substituted heterocyclic group refers to a “substituted heterocyclic group” in a “substituted or unsubstituted heterocyclic group.” A simply termed “heterocyclic group” herein includes both of an “unsubstituted heterocyclic group” and a “substituted heterocyclic group.”
The “substituted heterocyclic group” refers to a group derived by substituting at least one hydrogen atom in an “unsubstituted heterocyclic group” with a substituent. Specific examples of the “substituted heterocyclic group” include a group derived by substituting at least one hydrogen atom in the “unsubstituted heterocyclic group” in the specific example group G2A below with a substituent, and examples of the substituted heterocyclic group in the specific example group G2B below. It should be noted that the examples of the “unsubstituted heterocyclic group” and the “substituted heterocyclic group” mentioned herein are merely exemplary, and the “substituted heterocyclic group” mentioned herein includes a group derived by further substituting a hydrogen atom bonded to a ring atom of a skeleton of a “substituted heterocyclic group” in the specific example group G2B below, and a group derived by further substituting a hydrogen atom of a substituent of the “substituted heterocyclic group” in the specific example group G2B below.
The specific example group G2A includes, for instance, unsubstituted heterocyclic groups including a nitrogen atom (specific example group G2A1) below, unsubstituted heterocyclic groups including an oxygen atom (specific example group G2A2) below, unsubstituted heterocyclic groups including a sulfur atom (specific example group G2A3) below, and monovalent heterocyclic groups (specific example group G2A4) derived by removing a hydrogen atom from cyclic structures represented by formulae (TEMP-16) to (TEMP-33) below.
The specific example group G2B includes, for instance, substituted heterocyclic groups including a nitrogen atom (specific example group G2B1) below, substituted heterocyclic groups including an oxygen atom (specific example group G2B2) below, substituted heterocyclic groups including a sulfur atom (specific example group G2B3) below, and groups derived by substituting at least one hydrogen atom of the monovalent heterocyclic groups (specific example group G2B4) derived from the cyclic structures represented by formulae (TEMP-16) to (TEMP-33) below.
pyrrolyl group, imidazolyl group, pyrazolyl group, triazolyl group, tetrazolyl group, oxazolyl group, isoxazolyl group, oxadiazolyl group, thiazolyl group, isothiazolyl group, thiadiazolyl group, pyridyl group, pyridazynyl group, pyrimidinyl group, pyrazinyl group, triazinyl group, indolyl group, isoindolyl group, indolizinyl group, quinolizinyl group, quinolyl group, isoquinolyl group, cinnolyl group, phthalazinyl group, quinazolinyl group, quinoxalinyl group, benzimidazolyl group, indazolyl group, phenanthrolinyl group, phenanthridinyl group, acridinyl group, phenazinyl group, carbazolyl group, benzocarbazolyl group, morpholino group, phenoxazinyl group, phenothiazinyl group, azacarbazolyl group, and diazacarbazolyl group.
furyl group, oxazolyl group, isoxazolyl group, oxadiazolyl group, xanthenyl group, benzofuranyl group, isobenzofuranyl group, dibenzofuranyl group, naphthobenzofuranyl group, benzoxazolyl group, benzisoxazolyl group, phenoxazinyl group, morpholino group, dinaphthofuranyl group, azadibenzofuranyl group, diazadibenzofuranyl group, azanaphthobenzofuranyl group, and diazanaphthobenzofuranyl group.
thienyl group, thiazolyl group, isothiazolyl group, thiadiazolyl group, benzothiophenyl group (benzothienyl group), isobenzothiophenyl group (isobenzothienyl group), dibenzothiophenyl group (dibenzothienyl group), naphthobenzothiophenyl group (nahthobenzothienyl group), benzothiazolyl group, benzisothiazolyl group, phenothiazinyl group, dinaphthothiophenyl group (dinaphthothienyl group), azadibenzothiophenyl group (azadibenzothienyl group), diazadibenzothiophenyl group (diazadibenzothienyl group), azanaphthobenzothiophenyl group (azanaphthobenzothienyl group), and diazanaphthobenzothiophenyl group (diazanaphthobenzothienyl group).
Monovalent Heterocyclic Groups Derived by Removing One Hydrogen Atom from Cyclic Structures Represented by Formulae (TEMP-16) to (TEMP-33) (Specific Example Group G2A4):
In the formulae (TEMP-16) to (TEMP-33), XA and YA are each independently an oxygen atom, a sulfur atom, NH or CH2, with a proviso that at least one of XA or YA is an oxygen atom, a sulfur atom, or NH.
When at least one of XA or YA in the formulae (TEMP-16) to (TEMP-33) is NH or CH2, the monovalent heterocyclic groups derived from the cyclic structures represented by the formulae (TEMP-16) to (TEMP-33) include a monovalent group derived by removing one hydrogen atom from NH or CH2.
(9-phenyl)carbazolyl group, (9-biphenylyl)carbazolyl group, (9-phenyl)phenylcarbazolyl group, (9-naphthyl)carbazolyl group, diphenylcarbazole-9-yl group, phenylcarbazole-9-yl group, methylbenzimidazolyl group, ethylbenzimidazolyl group, phenyltriazinyl group, biphenylyltriazinyl group, diphenyltriazinyl group, phenylquinazolinyl group, and biphenylquinazolinyl group.
phenyldibenzofuranyl group, methyldibenzofuranyl group, t-butyldibenzofuranyl group, and monovalent residue of spiro[9H-xanthene-9,9′-[9H]fluorene].
phenyldibenzothiophenyl group, methyldibenzothiophenyl group, t-butyldibenzothiophenyl group, and monovalent residue of spiro[9H-thioxanthene-9,9′-[9H]fluorene].
Groups Obtained by Substituting at Least One Hydrogen Atom of Monovalent Heterocyclic Group Derived from Cyclic Structures Represented by Formulae (TEMP-16) to (TEMP-33) with Substituent (Specific Example Group G2B4):
The “at least one hydrogen atom of a monovalent heterocyclic group” means at least one hydrogen atom selected from a hydrogen atom bonded to a ring carbon atom of the monovalent heterocyclic group, a hydrogen atom bonded to a nitrogen atom of at least one of XA or YA in a form of NH, and a hydrogen atom of one of XA and YA in a form of a methylene group (CH2).
Specific examples (specific example group G3) of the “substituted or unsubstituted alkyl group” mentioned herein include unsubstituted alkyl groups (specific example group G3A) and substituted alkyl groups (specific example group G3B) below. Herein, an unsubstituted alkyl group refers to an “unsubstituted alkyl group” in a “substituted or unsubstituted alkyl group,” and a substituted alkyl group refers to a “substituted alkyl group” in a “substituted or unsubstituted alkyl group.” A simply termed “alkyl group” herein includes both of an “unsubstituted alkyl group” and a “substituted alkyl group.”
The “substituted alkyl group” refers to a group derived by substituting at least one hydrogen atom in an “unsubstituted alkyl group” with a substituent. Specific examples of the “substituted alkyl group” include a group derived by substituting at least one hydrogen atom of an “unsubstituted alkyl group” (specific example group G3A) below with a substituent, and examples of the substituted alkyl group (specific example group G3B) below. Herein, the alkyl group for the “unsubstituted alkyl group” refers to a chain alkyl group. Accordingly, the “unsubstituted alkyl group” include linear “unsubstituted alkyl group” and branched “unsubstituted alkyl group.” It should be noted that the examples of the “unsubstituted alkyl group” and the “substituted alkyl group” mentioned herein are merely exemplary, and the “substituted alkyl group” mentioned herein includes a group derived by further substituting a hydrogen atom of a skeleton of the “substituted alkyl group” in the specific example group G3B, and a group derived by further substituting a hydrogen atom of a substituent of the “substituted alkyl group” in the specific example group G3B.
methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, and t-butyl group.
heptafluoropropyl group (including isomer thereof), pentafluoroethyl group, 2,2,2-trifluoroethyl group, and trifluoromethyl group.
Specific examples (specific example group G4) of the “substituted or unsubstituted alkenyl group” mentioned herein include unsubstituted alkenyl groups (specific example group G4A) and substituted alkenyl groups (specific example group G4B). Herein, an unsubstituted alkenyl group refers to an “unsubstituted alkenyl group” in a “substituted or unsubstituted alkenyl group,” and a substituted alkenyl group refers to a “substituted alkenyl group” in a “substituted or unsubstituted alkenyl group.” A simply termed “alkenyl group” herein includes both of an “unsubstituted alkenyl group” and a “substituted alkenyl group.”
The “substituted alkenyl group” refers to a group derived by substituting at least one hydrogen atom in an “unsubstituted alkenyl group” with a substituent. Specific examples of the “substituted alkenyl group” include an “unsubstituted alkenyl group” (specific example group G4A) substituted by a substituent, and examples of the substituted alkenyl group (specific example group G4B) below. It should be noted that the examples of the “unsubstituted alkenyl group” and the “substituted alkenyl group” mentioned herein are merely exemplary, and the “substituted alkenyl group” mentioned herein includes a group derived by further substituting a hydrogen atom of a skeleton of the “substituted alkenyl group” in the specific example group G4B with a substituent, and a group derived by further substituting a hydrogen atom of a substituent of the “substituted alkenyl group” in the specific example group G4B with a substituent.
vinyl group, allyl group, 1-butenyl group, 2-butenyl group, and 3-butenyl group.
1,3-butanedienyl group, 1-methylvinyl group, 1-methylallyl group, 1,1-dimethylallyl group, 2-methylallyl group, and 1,2-dimethylallyl group.
Specific examples (specific example group G5) of the “substituted or unsubstituted alkynyl group” mentioned herein include unsubstituted alkynyl groups (specific example group G5A) below. Herein, an unsubstituted alkynyl group refers to an “unsubstituted alkynyl group” in a “substituted or unsubstituted alkynyl group.” A simply termed “alkynyl group” herein includes both of “unsubstituted alkynyl group” and “substituted alkynyl group.”
The “substituted alkynyl group” refers to a group derived by substituting at least one hydrogen atom in an “unsubstituted alkynyl group” with a substituent. Specific examples of the “substituted alkynyl group” include a group derived by substituting at least one hydrogen atom of the “unsubstituted alkynyl group” (specific example group G5A) below with a substituent.
ethynyl group
Specific examples (specific example group G6) of the “substituted or unsubstituted cycloalkyl group” mentioned herein include unsubstituted cycloalkyl groups (specific example group G6A) and substituted cycloalkyl groups (specific example group G6B). Herein, an unsubstituted cycloalkyl group refers to an “unsubstituted cycloalkyl group” in a “substituted or unsubstituted cycloalkyl group,” and a substituted cycloalkyl group refers to a “substituted cycloalkyl group” in a “substituted or unsubstituted cycloalkyl group.” A simply termed “cycloalkyl group” herein includes both of “unsubstituted cycloalkyl group” and “substituted cycloalkyl group.”
The “substituted cycloalkyl group” refers to a group derived by substituting at least one hydrogen atom of an “unsubstituted cycloalkyl group” with a substituent. Specific examples of the “substituted cycloalkyl group” include a group derived by substituting at least one hydrogen atom of the “unsubstituted cycloalkyl group” (specific example group G6A) below with a substituent, and examples of the substituted cycloalkyl group (specific example group G6B) below. It should be noted that the examples of the “unsubstituted cycloalkyl group” and the “substituted cycloalkyl group” mentioned herein are merely exemplary, and the “substituted cycloalkyl group” mentioned herein includes a group derived by substituting at least one hydrogen atom bonded to a carbon atom of a skeleton of the “substituted cycloalkyl group” in the specific example group G6B with a substituent, and a group derived by further substituting a hydrogen atom of a substituent of the “substituted cycloalkyl group” in the specific example group G6B with a substituent.
cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-adamantyl group, 1-norbornyl group, and 2-norbornyl group.
4-methylcyclohexyl group.
Group Represented by —Si(R901)(R902)(R903)
Specific examples (specific example group G7) of the group represented herein by —Si(R901)(R902)(R903) include: —Si(G1)(G1)(G1); —Si(G1)(G2)(G2); —Si(G1)(G1)(G2); —Si(G2)(G2)(G2); —Si(G3)(G3)(G3); and —Si(G6)(G6)(G6); where:
G1 represents a “substituted or unsubstituted aryl group” in the specific example group G1;
G2 represents a “substituted or unsubstituted heterocyclic group” in the specific example group G2;
G3 represents a “substituted or unsubstituted alkyl group” in the specific example group G3;
G6 represents a “substituted or unsubstituted cycloalkyl group” in the specific example group G6;
a plurality of G1 in —Si(G1)(G1)(G1) are mutually the same or different;
a plurality of G2 in —Si(G1)(G2)(G2) are mutually the same or different;
a plurality of G1 in —Si(G1)(G1)(G2) are mutually the same or different;
a plurality of G2 in —Si(G2)(G2)(G2) are mutually the same or different;
a plurality of G3 in —Si(G3)(G3)(G3) are mutually the same or different; and
a plurality of G6 in —Si(G6)(G6)(G6) are mutually the same or different.
Specific examples (specific example group G8) of a group represented by —O—(R904) herein include: —O(G1); —O(G2); —O(G3); and —O(G6);
where:
G1 represents a “substituted or unsubstituted aryl group” in the specific example group G1;
G2 represents a “substituted or unsubstituted heterocyclic group” in the specific example group G2;
G3 represents a “substituted or unsubstituted alkyl group” in the specific example group G3; and
G6 represents a “substituted or unsubstituted cycloalkyl group” in the specific example group G6.
Specific examples (specific example group G9) of a group represented herein by —S—(R905) include: —S(G1); —S(G2); —S(G3); and —S(G6);
where:
G1 represents a “substituted or unsubstituted aryl group” in the specific example group G1;
G2 represents a “substituted or unsubstituted heterocyclic group” in the specific example group G2;
G3 represents a “substituted or unsubstituted alkyl group” in the specific example group G3; and
G6 represents a “substituted or unsubstituted cycloalkyl group” in the specific example group G6.
Group Represented by —N(R906)(R907)
Specific examples (specific example group G10) of a group represented herein by —N(R906)(R907) include: —N(G1)(G1); —N(G2)(G2); —N(G1)(G2); —N(G3)(G3); and —N(G6)(G6),
where:
G1 represents a “substituted or unsubstituted aryl group” in the specific example group G1;
G2 represents a “substituted or unsubstituted heterocyclic group” in the specific example group G2;
G3 represents a “substituted or unsubstituted alkyl group” in the specific example group G3;
G6 represents a “substituted or unsubstituted cycloalkyl group” in the specific example group G6;
a plurality of G1 in —N(G1)(G1) are mutually the same or different;
a plurality of G2 in —N(G2)(G2) are mutually the same or different;
a plurality of G3 in —N(G3)(G3) are mutually the same or different; and
a plurality of G6 in —N(G6)(G6) are mutually the same or different.
Specific examples (specific example group G11) of “halogen atom” mentioned herein include a fluorine atom, chlorine atom, bromine atom, and iodine atom.
The “substituted or unsubstituted fluoroalkyl group” mentioned herein refers to a group derived by substituting at least one hydrogen atom bonded to at least one of carbon atoms forming an alkyl group in the “substituted or unsubstituted alkyl group” with a fluorine atom, and also includes a group (perfluoro group) derived by substituting all of hydrogen atoms bonded to carbon atoms forming the alkyl group in the “substituted or unsubstituted alkyl group” with fluorine atoms. An “unsubstituted fluoroalkyl group” has, unless otherwise specified herein, 1 to 50, preferably 1 to 30, more preferably 1 to 18 carbon atoms. The “substituted fluoroalkyl group” refers to a group derived by substituting at least one hydrogen atom in a “fluoroalkyl group” with a substituent. It should be noted that the examples of the “substituted fluoroalkyl group” mentioned herein include a group derived by further substituting at least one hydrogen atom bonded to a carbon atom of an alkyl chain of a “substituted fluoroalkyl group” with a substituent, and a group derived by further substituting at least one hydrogen atom of a substituent of the “substituted fluoroalkyl group” with a substituent. Specific examples of the “substituted fluoroalkyl group” include a group derived by substituting at least one hydrogen atom of the “alkyl group” (specific example group G3) with a fluorine atom.
The “substituted or unsubstituted haloalkyl group” mentioned herein refers to a group derived by substituting at least one hydrogen atom bonded to carbon atoms forming the alkyl group in the “substituted or unsubstituted alkyl group” with a halogen atom, and also includes a group derived by substituting all hydrogen atoms bonded to carbon atoms forming the alkyl group in the “substituted or unsubstituted alkyl group” with halogen atoms. An “unsubstituted haloalkyl group” has, unless otherwise specified herein, 1 to 50, preferably 1 to 30, and more preferably 1 to 18 carbon atoms. The “substituted haloalkyl group” refers to a group derived by substituting at least one hydrogen atom in a “haloalkyl group” with a substituent. It should be noted that the examples of the “substituted haloalkyl group” mentioned herein include a group derived by further substituting at least one hydrogen atom bonded to a carbon atom of an alkyl chain of a “substituted haloalkyl group” with a substituent, and a group derived by further substituting at least one hydrogen atom of a substituent of the “substituted haloalkyl group” with a substituent. Specific examples of the “substituted haloalkyl group” include a group derived by substituting at least one hydrogen atom of the “alkyl group” (specific example group G3) with a halogen atom. The haloalkyl group is sometimes referred to as a halogenated alkyl group.
Specific examples of a “substituted or unsubstituted alkoxy group” mentioned herein include a group represented by —O(G3), G3 being the “substituted or unsubstituted alkyl group” in the specific example group G3. An “unsubstituted alkoxy group” has, unless otherwise specified herein, 1 to 50, preferably 1 to 30, more preferably 1 to 18 carbon atoms.
Substituted or Unsubstituted Alkylthio Group Specific examples of a “substituted or unsubstituted alkylthio group” mentioned herein include a group represented by —S(G3), G3 being the “substituted or unsubstituted alkyl group” in the specific example group G3. An “unsubstituted alkylthio group” has, unless otherwise specified herein, 1 to 50, preferably 1 to 30, more preferably 1 to 18 carbon atoms.
Specific examples of a “substituted or unsubstituted aryloxy group” mentioned herein include a group represented by —O(G1), G1 being the “substituted or unsubstituted aryl group” in the specific example group G1. An “unsubstituted aryloxy group” has, unless otherwise specified herein, 6 to 50, preferably 6 to 30, more preferably 6 to 18 ring carbon atoms.
Specific examples of a “substituted or unsubstituted arylthio group” mentioned herein include a group represented by —S(G1), G1 being the “substituted or unsubstituted aryl group” in the specific example group G1. An “unsubstituted arylthio group” has, unless otherwise specified herein, 6 to 50, preferably 6 to 30, more preferably 6 to 18 ring carbon atoms.
Specific examples of a “trialkylsilyl group” mentioned herein include a group represented by —Si(G3)(G3)(G3), G3 being the “substituted or unsubstituted alkyl group” in the specific example group G3. The plurality of G3 in —Si(G3)(G3)(G3) are mutually the same or different. Each of the alkyl groups in the “trialkylsilyl group” has, unless otherwise specified herein, 1 to 50, preferably 1 to 20, more preferably 1 to 6 carbon atoms.
Specific examples of a “substituted or unsubstituted aralkyl group” mentioned herein include a group represented by (G3)-(G1), G3 being the “substituted or unsubstituted alkyl group” in the specific example group G3, G1 being the “substituted or unsubstituted aryl group” in the specific example group G1. Accordingly, the “aralkyl group” is a group derived by substituting a hydrogen atom of the “alkyl group” with a substituent in a form of the “aryl group,” which is an example of the “substituted alkyl group.” An “unsubstituted aralkyl group,” which is an “unsubstituted alkyl group” substituted by an “unsubstituted aryl group,” has, unless otherwise specified herein, 7 to 50 carbon atoms, preferably 7 to 30 carbon atoms, more preferably 7 to 18 carbon atoms.
Specific examples of the “substituted or unsubstituted aralkyl group” include a benzyl group, 1-phenylethyl group, 2-phenylethyl group, 1-phenylisopropyl group, 2-phenylisopropyl group, phenyl-t-butyl group, α-naphthylmethyl group, 1-α-naphthylethyl group, 2-α-naphthylethyl group, 1-α-naphthylisopropyl group, 2-α-naphthylisopropyl group, β-naphthylmethyl group, 1-β-naphthylethyl group, 2-β-naphthylethyl group, 1-β-naphthylisopropyl group, and 2-β-naphthylisopropyl group.
Preferable examples of the substituted or unsubstituted aryl group mentioned herein include, unless otherwise specified herein, a phenyl group, p-biphenyl group, m-biphenyl group, o-biphenyl group, p-terphenyl-4-yl group, p-terphenyl-3-yl group, p-terphenyl-2-yl group, m-terphenyl-4-yl group, m-terphenyl-3-yl group, m-terphenyl-2-yl group, o-terphenyl-4-yl group, o-terphenyl-3-yl group, o-terphenyl-2-yl group, 1-naphthyl group, 2-naphthyl group, anthryl group, phenanthryl group, pyrenyl group, chrysenyl group, triphenylenyl group, fluorenyl group, 9,9′-spirobifluorenyl group, 9,9-dimethylfluorenyl group, and 9,9-diphenylfluorenyl group.
Preferable examples of the substituted or unsubstituted heterocyclic group mentioned herein include, unless otherwise specified herein, a pyridyl group, pyrimidinyl group, triazinyl group, quinolyl group, isoquinolyl group, quinazolinyl group, benzimidazolyl group, phenanthrolinyl group, carbazolyl group (1-carbazolyl group, 2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group, or 9-carbazolyl group), benzocarbazolyl group, azacarbazolyl group, diazacarbazolyl group, dibenzofuranyl group, naphthobenzofuranyl group, azadibenzofuranyl group, diazadibenzofuranyl group, dibenzothiophenyl group, naphthobenzothiophenyl group, azadibenzothiophenyl group, diazadibenzothiophenyl group, (9-phenyl)carbazolyl group ((9-phenyl)carbazole-1-yl group, (9-phenyl)carbazole-2-yl group, (9-phenyl)carbazole-3-yl group, or (9-phenyl)carbazole-4-yl group), (9-biphenylyl)carbazolyl group, (9-phenyl)phenylcarbazolyl group, diphenylcarbazole-9-yl group, phenylcarbazole-9-yl group, phenyltriazinyl group, biphenylyltriazinyl group, diphenyltriazinyl group, phenyldibenzofuranyl group, and phenyldibenzothiophenyl group.
The carbazolyl group mentioned herein is, unless otherwise specified herein, specifically a group represented by one of formulae below.
The (9-phenyl)carbazolyl group mentioned herein is, unless otherwise specified herein, specifically a group represented by one of formulae below.
In the formulae (TEMP-Cz1) to (TEMP-Cz9), * represents a bonding position.
The dibenzofuranyl group and dibenzothiophenyl group mentioned herein are, unless otherwise specified herein, each specifically represented by one of formulae below.
In the formulae (TEMP-34) to (TEMP-41), * represents a bonding position.
Preferable examples of the substituted or unsubstituted alkyl group mentioned herein include, unless otherwise specified herein, a methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, and t-butyl group.
The “substituted or unsubstituted arylene group” mentioned herein is, unless otherwise specified herein, a divalent group derived by removing one hydrogen atom on an aryl ring of the “substituted or unsubstituted aryl group.” Specific examples of the “substituted or unsubstituted arylene group” (specific example group G12) include a divalent group derived by removing one hydrogen atom on an aryl ring of the “substituted or unsubstituted aryl group” in the specific example group G1.
The “substituted or unsubstituted divalent heterocyclic group” mentioned herein is, unless otherwise specified herein, a divalent group derived by removing one hydrogen atom on a heterocycle of the “substituted or unsubstituted heterocyclic group.” Specific examples of the “substituted or unsubstituted divalent heterocyclic group” (specific example group G13) include a divalent group derived by removing one hydrogen atom on a heterocyclic ring of the “substituted or unsubstituted heterocyclic group” in the specific example group G2.
The “substituted or unsubstituted alkylene group” mentioned herein is, unless otherwise specified herein, a divalent group derived by removing one hydrogen atom on an alkyl chain of the “substituted or unsubstituted alkyl group.” Specific examples of the “substituted or unsubstituted alkylene group” (specific example group G14) include a divalent group derived by removing one hydrogen atom on an alkyl chain of the “substituted or unsubstituted alkyl group” in the specific example group G3.
The substituted or unsubstituted arylene group mentioned herein is, unless otherwise specified herein, preferably any one of groups represented by formulae (TEMP-42) to (TEMP-68) below.
In the formulae (TEMP-42) to (TEMP-52), Q1 to Q10 are each independently a hydrogen atom or a substituent.
In the formulae (TEMP-42) to (TEMP-52), * represents a bonding position.
In the formulae (TEMP-53) to (TEMP-62), Q1 to Q10 are each independently a hydrogen atom or a substituent.
In the formulae, Q9 and Q10 may be mutually bonded through a single bond to form a ring.
In the formulae (TEMP-53) to (TEMP-62), * represents a bonding position.
In the formulae (TEMP-63) to (TEMP-68), Q1 to Q8 are each independently a hydrogen atom or a substituent.
In the formulae (TEMP-63) to (TEMP-68), * represents a bonding position.
The substituted or unsubstituted divalent heterocyclic group mentioned herein is, unless otherwise specified herein, preferably a group represented by any one of formulae (TEMP-69) to (TEMP-102) below.
In the formulae (TEMP-69) to (TEMP-82), Q1 to Q9 are each independently a hydrogen atom or a substituent.
In the formulae (TEMP-83) to (TEMP-102), Q1 to Q8 are each independently a hydrogen atom or a substituent.
The substituent mentioned herein has been described above.
Instances where “at least one combination of adjacent two or more (of . . . ) are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded” mentioned herein refer to instances where “at least one combination of adjacent two or more (of . . . ) are mutually bonded to form a substituted or unsubstituted monocyclic ring, “at least one combination of adjacent two or more (of . . . ) are mutually bonded to form a substituted or unsubstituted fused ring,” and “at least one combination of adjacent two or more (of . . . ) are not mutually bonded.”
Instances where “at least one combination of adjacent two or more (of . . . ) are mutually bonded to form a substituted or unsubstituted monocyclic ring” and “at least one combination of adjacent two or more (of . . . ) are mutually bonded to form a substituted or unsubstituted fused ring” mentioned herein (these instances will be sometimes collectively referred to as an instance of “bonded to form a ring” hereinafter) will be described below. An anthracene compound having a basic skeleton in a form of an anthracene ring and represented by a formula (TEMP-103) below will be used as an example for the description.
For instance, when “at least one combination of adjacent two or more of R921 to R930 are mutually bonded to form a ring,” the combination of adjacent ones of R921 to R930 (i.e. the combination at issue) is a combination of R921 and R922, a combination of R922 and R923, a combination of R923 and R924, a combination of R924 and R930, a combination of R930 and R925, a combination of R925 and R926, a combination of R926 and R927, a combination of R927 and R928, a combination of R928 and R929, or a combination of R929 and R921.
The term “at least one combination” means that two or more of the above combinations of adjacent two or more of R921 to R930 may simultaneously form rings. For instance, when R921 and R922 are mutually bonded to form a ring QA and R925 and R926 are simultaneously mutually bonded to form a ring QB, the anthracene compound represented by the formula (TEMP-103) is represented by a formula (TEMP-104) below.
The instance where the “combination of adjacent two or more” form a ring means not only an instance where the “two” adjacent components are bonded but also an instance where adjacent “three or more” are bonded. For instance, R921 and R922 are mutually bonded to form a ring QA and R922 and R923 are mutually bonded to form a ring QC, and mutually adjacent three components (R921, R922 and R923) are mutually bonded to form a ring fused to the anthracene basic skeleton. In this case, the anthracene compound represented by the formula (TEMP-103) is represented by a formula (TEMP-105) below. In the formula (TEMP-105) below, the ring QA and the ring QC share R922.
The formed “monocyclic ring” or “fused ring” may be, in terms of the formed ring in itself, a saturated ring or an unsaturated ring. When the “combination of adjacent two” form a “monocyclic ring” or a “fused ring,” the “monocyclic ring” or “fused ring” may be a saturated ring or an unsaturated ring. For instance, the ring QA and the ring QB formed in the formula (TEMP-104) are each independently a “monocyclic ring” or a “fused ring.” Further, the ring QA and the ring QC formed in the formula (TEMP-105) are each a “fused ring.” The ring QA and the ring QC in the formula (TEMP-105) are fused to form a fused ring. When the ring QA in the formula (TEMP-104) is a benzene ring, the ring QA is a monocyclic ring. When the ring QA in the formula (TEMP-104) is a naphthalene ring, the ring QA is a fused ring.
The “unsaturated ring” represents an aromatic hydrocarbon ring or an aromatic heterocycle. The “saturated ring” represents an aliphatic hydrocarbon ring or a non-aromatic heterocycle.
Specific examples of the aromatic hydrocarbon ring include a ring formed by terminating a bond of a group in the specific example of the specific example group G1 with a hydrogen atom.
Specific examples of the aromatic heterocycle include a ring formed by terminating a bond of an aromatic heterocyclic group in the specific example of the specific example group G2 with a hydrogen atom.
Specific examples of the aliphatic hydrocarbon ring include a ring formed by terminating a bond of a group in the specific example of the specific example group G6 with a hydrogen atom.
The phrase “to form a ring” herein means that a ring is formed only by a plurality of atoms of a basic skeleton, or by a combination of a plurality of atoms of the basic skeleton and one or more optional atoms. For instance, the ring QA formed by mutually bonding R921 and R922 shown in the formula (TEMP-104) is a ring formed by a carbon atom of the anthracene skeleton bonded to R921, a carbon atom of the anthracene skeleton bonded to R922, and one or more optional atoms. Specifically, when the ring QA is a monocyclic unsaturated ring formed by R921 and R922, the ring formed by a carbon atom of the anthracene skeleton bonded to R921, a carbon atom of the anthracene skeleton bonded to R922, and four carbon atoms is a benzene ring.
The “optional atom” is, unless otherwise specified herein, preferably at least one atom selected from the group consisting of a carbon atom, nitrogen atom, oxygen atom, and sulfur atom. A bond of the optional atom (e.g. a carbon atom and a nitrogen atom) not forming a ring may be terminated by a hydrogen atom or the like or may be substituted by an “optional substituent” described later. When the ring includes an optional element other than carbon atom, the resultant ring is a heterocycle.
The number of “one or more optional atoms” forming the monocyclic ring or fused ring is, unless otherwise specified herein, preferably in a range from 2 to 15, more preferably in a range from 3 to 12, further preferably in a range from 3 to 5.
Unless otherwise specified herein, the ring, which may be a “monocyclic ring” or “fused ring,” is preferably a “monocyclic ring.”
Unless otherwise specified herein, the ring, which may be a “saturated ring” or “unsaturated ring,” is preferably an “unsaturated ring.”
Unless otherwise specified herein, the “monocyclic ring” is preferably a benzene ring.
Unless otherwise specified herein, the “unsaturated ring” is preferably a benzene ring.
When “at least one combination of adjacent two or more” (of . . . ) are “mutually bonded to form a substituted or unsubstituted monocyclic ring” or “mutually bonded to form a substituted or unsubstituted fused ring,” unless otherwise specified herein, at least one combination of adjacent two or more of components are preferably mutually bonded to form a substituted or unsubstituted “unsaturated ring” formed of a plurality of atoms of the basic skeleton, and 1 to 15 atoms of at least one element selected from the group consisting of carbon, nitrogen, oxygen and sulfur.
When the “monocyclic ring” or the “fused ring” has a substituent, the substituent is the substituent described in later-described “optional substituent.” When the “monocyclic ring” or the “fused ring” has a substituent, specific examples of the substituent are the substituents described in the above under the subtitle “Substituent Mentioned Herein.”
When the “saturated ring” or the “unsaturated ring” has a substituent, the substituent is the substituent described in later-described “optional substituent.” When the “monocyclic ring” or the “fused ring” has a substituent, specific examples of the substituent are the substituents described in the above under the subtitle “Substituent Mentioned Herein.”
The above is the description for the instances where “at least one combination of adjacent two or more (of . . . ) are mutually bonded to form a substituted or unsubstituted monocyclic ring” and “at least one combination of adjacent two or more (of . . . ) are mutually bonded to form a substituted or unsubstituted fused ring” mentioned herein (sometimes referred to as an instance of “bonded to form a ring”).
In an exemplary embodiment herein, a substituent for the substituted or unsubstituted group (sometimes referred to as an “optional substituent” hereinafter) is, for instance, a group selected from the group consisting of an unsubstituted alkyl group having 1 to 50 carbon atoms, an unsubstituted alkenyl group having 2 to 50 carbon atoms, an unsubstituted alkynyl group having 2 to 50 carbon atoms, an unsubstituted cycloalkyl group having 3 to 50 ring carbon atoms, —Si(R901)(R902)(R903), —O—(R904), —S—(R905), —N(R906)(R907), a halogen atom, a cyano group, a nitro group, an unsubstituted aryl group having 6 to 50 ring carbon atoms, and an unsubstituted heterocyclic group having 5 to 50 ring atoms;
R901 to R907 are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 ring carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms;
when two or more R901 are present, the two or more R901 are mutually the same or different;
when two or more R902 are present, the two or more R902 are mutually the same or different;
when two or more R903 are present, the two or more R903 are mutually the same or different;
when two or more R904 are present, the two or more R904 are mutually the same or different;
when two or more R905 are present, the two or more R905 are mutually the same or different;
when two or more R906 are present, the two or more R906 are mutually the same or different; and
when two or more R907 are present, the two or more R907 are mutually the same or different.
In an exemplary embodiment, the substituent for the substituted or unsubstituted group is selected from the group consisting of an alkyl group having 1 to 50 carbon atoms, an aryl group having 6 to 50 ring carbon atoms, and a heterocyclic group having 5 to 50 ring atoms.
In an exemplary embodiment, the substituent for the substituted or unsubstituted group is selected from the group consisting of an alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 18 ring carbon atoms, and a heterocyclic group having 5 to 18 ring atoms.
Specific examples of the above optional substituent are the same as the specific examples of the substituent described in the above under the subtitle “Substituent Mentioned Herein.”
Unless otherwise specified herein, adjacent ones of the optional substituents may form a “saturated ring” or an “unsaturated ring,” preferably a substituted or unsubstituted saturated five-membered ring, a substituted or unsubstituted saturated six-membered ring, a substituted or unsubstituted unsaturated five-membered ring, or a substituted or unsubstituted unsaturated six-membered ring, more preferably a benzene ring.
Unless otherwise specified herein, the optional substituent may further include a substituent. Examples of the substituent for the optional substituent are the same as the examples of the optional substituent.
Herein, numerical ranges represented by “AA to BB” represent a range whose lower limit is the value (AA) recited before “to” and whose upper limit is the value (BB) recited after “to.”
Herein, a numerical formula represented by “A≥B” means that the value A is equal to the value B, or the value A is larger than the value B.
Herein, a numerical formula represented by “A≤B” means that the value A is equal to the value B, or the value A is smaller than the value B.
An arrangement of an organic EL device according to a first exemplary embodiment of the invention will be described below.
The organic EL device according to the exemplary embodiment includes an organic layer between both electrodes of an anode and a cathode. The organic layer includes at least one layer formed from an organic compound. Alternatively, the organic layer is provided by laminating a plurality of layers each formed from an organic compound. The organic layer may further contain an inorganic compound.
In the exemplary embodiment, at least three of the organic layers are an emitting layer provided between the anode and the cathode, a first layer provided between the emitting layer and the anode, and a second layer provided between the first layer and the cathode. For instance, the organic layer may be provided by the first layer and the second layer, or may further include at least one layer usable for an organic EL device. Examples of the layer usable in the organic EL device, which are not particularly limited, include at least one layer selected from the group consisting of a hole injecting layer, hole transporting layer, electron blocking layer, electron injecting layer, electron transporting layer, and hole blocking layer.
An organic EL device according to the exemplary embodiment includes: an anode; a cathode; an emitting layer provided between the anode and the cathode; a first layer provided between the anode and the emitting layer; and a second layer provided between the anode and the first layer, in which the emitting layer contains a delayed fluorescent compound, the first layer contains a first compound, the second layer contains a second compound, an ionization potential Ip(HT1) of the first compound satisfies a numerical formula (Numerical Formula 1) below, a hole mobility μh(HT1) of the first compound satisfies a numerical formula (Numerical Formula 2) below, an ionization potential Ip(HT2) of the second compound satisfies a numerical formula (Numerical Formula 3) below, and the first layer has a film thickness of 15 nm or more.
Ip(HT1)≥5.69 eV (Numerical Formula 1)
μh(HT1)≥1.00×10−5 cm2/Vs (Numerical Formula 2)
Ip(HT2)≥5.60 eV (Numerical Formula 3)
Herein, a zone disposed between the anode and the emitting layer and formed by a plurality of organic layers is occasionally referred to as a hole transporting zone. Herein, a layer provided in a shared manner across a plurality of devices is occasionally referred to as a common layer, and a layer not provided in a shared manner across a plurality of devices is occasionally referred to as a non-common layer.
In an organic EL device using a TADF mechanism, there is a demand for an increase in total film thickness of the hole transporting zone according to how the organic EL device is used. The reason thereof is explained below.
When organic EL devices are provided, as a red pixel, green pixel, and blue pixel (RGB pixels), in an organic EL display device, in order to improve mass productivity and reduce production costs, the hole transporting layer is typically formed, as the common layer, in a shared manner across the RGB pixels. The hole transporting layer is formed from the same material to have the same film thickness.
On the other hand, since cavity adjustment is performed for each pixel in the organic EL display device including the RGB pixels, the total film thickness of the hole transporting zone needs to be optimized for each pixel according to the emission wavelength. Specifically, the total film thickness of the hole transporting zone needs to be larger, as the emission wavelength of the pixel is longer. Here, the film thickness of the hole transporting layer as the common layer is determined according to the pixel of which wavelength is not the longest among the RGB pixels (in a case of RGB pixels only, B pixel having the shortest wavelength). Thus, the film thickness of the hole transporting layer as the common layer is insufficient (excessively thin) for the rest of the pixels. To increase the total film thickness of the hole transporting layer for the rest of the pixels, the film thickness of the non-common layer (e.g., electron blocking layer) in the hole transporting zone needs to be increased. However, when the film thickness of the non-common layer (e.g., electron blocking layer) in the hole transporting zone of any of the RGB pixels is simply increased in the above arrangement where the film thickness of the hole transporting layer as the common layer is determined according to the pixel of which wavelength is not the longest among the RGB pixels, the device performance is decreased (especially, an increase in voltage). Measures are thus needed to solve the problem.
In conventional techniques, an increase in film thickness while keeping low voltage has been performed as follows: in a case where the pixel of which film thickness needs to increase is a phosphorescent pixel, the non-common layer (e.g., electron blocking layer) with an increased film thickness is provided in the hole transporting zone, and a material having a small absolute value of the ionization potential Ip is contained in the hole transporting layer as the common layer. However, in a case where the pixel of which film thickness needs to increase is a pixel that emits light using the TADF mechanism, studies for increasing the film thickness of the non-common layer have not been performed.
Inventors of the invention have studied for inhibiting a decrease in device performance (especially, an increase in voltage) even when the film thickness of the non-common layer (e.g., electron blocking layer) is increased in an arrangement using the TADF emitting layer.
The inventors of the invention have found out that the arrangement using the TADF emitting layer has the following problem: unlike a case where a phosphorescent emitting layer is used, when the non-common layer with an increased film thickness is simply provided and a material having a small absolute value of the ionization potential Ip is contained in the hole transporting layer as the common layer, voltage in the device is increased, making it impossible to practically use the device. The reason thereof is considered that the absolute value of the ionization potential Ip of the TADF emitting layer is larger than that of the phosphorescent emitting layer.
In order to solve the problem in which high voltage in the device makes it impossible to practically use the device, the inventors have found out that both luminous efficiency and voltage suitable for practical use can be achieved by increasing the film thickness of the first layer (e.g., electron blocking layer) disposed between the emitting layer and the anode to 15 nm or more and containing the first compound (Numerical Formula 2), in which the absolute value of the ionization potential Ip is large (Numerical Formula 1) and the hole mobility μh(HT1) is high, in the first layer having an increased film thickness, and containing the second compound (Numerical Formula 3), in which the absolute value of the ionization potential Ip is large, in the second layer (e.g., hole transporting layer) disposed between the first layer and the anode.
Using the second compound in which the absolute value of the ionization potential Ip is large can improve hole injection from the second layer to the first layer. The second compound satisfying Numerical Formula 3 thus contributes to a decrease in voltage in the device.
According to the organic EL device of the exemplary embodiment, higher performance (especially, a decrease in voltage), specifically, both luminous efficiency and voltage suitable for practical use can be achieved, even when the first layer has an increased film thickness.
Further, when the organic EL device according to the exemplary embodiment is provided in an organic EL display device in which at least one of the RGB pixels emits light using the TADF mechanism, cavity adjustment can be easily performed by simply increasing the film thickness of the first layer. Furthermore, the organic EL display device can be improved in mass productivity.
Literature 1 (WO 2020/241580), Literature 2 (WO 2019/013063), and Literature 3 (U.S. Patent Application Publication No. 2020/0203621) describe an organic EL device using a TADF emitting layer. However, in the organic EL device described in Literatures 1 and 2, the film thickness of the first layer (hole transporting layer or electron blocking layer close to the emitting layer) is not increased.
In the organic EL device described in Literature 3, the film thickness of the first layer (hole transporting layer or electron blocking layer close to the emitting layer) is increased. However, the ionization potential Ip of the compound used for the first layer fails to satisfy Numerical Formula 1. Further, Literature 3 does not describe a problem that may be caused when the film thickness of the first layer is increased.
Accordingly, none of Literatures 1 to 3 pay attention to the fact that a decrease in device performance is inhibited in the device having the first layer with an increased film thickness. Further, none of Literatures 1 to 3 pay attention to parameters (ionization potential Ip and hole mobility μh) of the compound used for the first layer and parameters (ionization potential Ip) of the compound used for the second layer (e.g., hole transporting layer close to the anode).
In the organic EL device according to the exemplary embodiment, the ionization potential Ip(HT1) of the first compound and the ionization potential Ip(HT2) of the second compound preferably satisfy a numerical formula (Numerical Formula 10) below. This facilitates a decrease in voltage in the device.
Ip(HT1)>Ip(HT2) (Numerical Formula 10)
An organic EL device 1 includes a light-transmissive substrate 2, an anode 3, a cathode 4, and an organic layer 10 provided between the anode 3 and the cathode 4. The organic layer 10 is provided by layering, on the anode 3, an anode-side organic layer 63, a second layer 62, a first layer 61, an emitting layer 5, an electron transporting layer 8, and an electron injecting layer 9 in this order. In
In the organic EL device 1 of
The first layer 61 is preferably in direct contact with the emitting layer 5.
The first layer 61 is also preferably in direct contact with the second layer 62.
The first layer 61 is preferably a hole transporting layer or electron blocking layer, more preferably an electron blocking layer.
The second layer 62 is preferably in direct contact with the first layer 61.
The second layer 62 is also preferably in direct contact with the anode-side organic layer 63.
The second layer 62 is preferably a hole transporting layer.
The anode-side organic layer 63 is also preferably in direct contact with the second layer 62.
The anode-side organic layer 63 is also preferably in direct contact with the anode 3.
The anode-side organic layer 63 is preferably a hole injecting layer or hole transporting layer, more preferably a hole injecting layer.
The anode-side organic layer 63 can be provided by using, for instance, materials for the hole injecting layer and hole transporting layer described in after-described Arrangement of Organic EL Device.
The emitting layer 5 preferably contains no phosphorescent material (dopant material).
The emitting layer 5 preferably contains no phosphorescent metal complex.
The emitting layer 5 preferably contains no heavy metal complex. Examples of the heavy metal complex include an iridium complex, osmium complex, and platinum complex.
The emitting layer 5 preferably contains no phosphorescent rare-earth metal complex.
The emitting layer 5 may contain a metal complex, but preferably contains no metal complex.
In an exemplary arrangement of the exemplary embodiment, the first layer has a film thickness of 25 nm or more.
In another exemplary arrangement of the exemplary embodiment, the first layer has a film thickness of 35 nm or more.
In still another exemplary arrangement of the exemplary embodiment, the first layer has a film thickness of 45 nm or more.
In a further exemplary arrangement of the exemplary embodiment, the first layer has a film thickness of 55 nm or more.
In a still further exemplary arrangement of the exemplary embodiment, the first layer has a film thickness of 110 nm or less.
In a still further exemplary arrangement of the exemplary embodiment, the first layer has a film thickness of 100 nm or less.
In a still further exemplary arrangement of the exemplary embodiment, the first layer has a film thickness of 90 nm or less.
In an exemplary arrangement of the exemplary embodiment, the second layer has a film thickness of 80 nm or more.
In another exemplary arrangement of the exemplary embodiment, the second layer has a film thickness of 90 nm or more.
In still another exemplary arrangement of the exemplary embodiment, the second layer has a film thickness of 100 nm or more.
In a further exemplary arrangement of the exemplary embodiment, the second layer has a film thickness of 140 nm or less.
In a still further exemplary arrangement of the exemplary embodiment, the second layer has a film thickness of 130 nm or less.
In a still further exemplary arrangement of the exemplary embodiment, the second layer has a film thickness of 120 nm or less.
The first layer contains the first compound.
The first compound may be any compound having an ionization potential Ip(HT1) of 5.69 eV or more (Numerical Formula 1) and a hole mobility μh(HT1) of 1.00×10−5 cm2/Vs or more (Numerical Formula 2).
The first compound is preferably an amine compound.
As the first compound, for instance, a compound having an ionization potential Ip(HT1) of 5.69 eV or more and a hole mobility μh(HT1) of 1.00×10−5 cm2/Vs or more can be selected for use from compounds represented by formulae (31) to (33) and a formula (X) below.
In the formulae (31) to (33):
Ar1 and Ar2 are each independently a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms;
each Ar3 is independently a group represented by a formula (3A) or (3B); in the formula (32), * represents a bonding position to a carbon atom in a six-membered ring having Ra; in the formula (33), * represents a bonding position to a carbon atom in a six-membered ring having Ra; and in the formula (33), 1* represents a bonding position to a carbon atom in a six-membered ring having Ra;
at least one combination of adjacent two or more of a plurality of Ra are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded;
Ra forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted haloalkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 50 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 ring carbon atoms, a group represented by —Si(R901)(R902)(R903), a group represented by —O—(R904), a group represented by —S—(R905), a group represented by —N(R906)(R907), a substituted or unsubstituted aralkyl group having 7 to 50 carbon atoms, a group represented by —C(═O)R908, a group represented by —COOR909, a halogen atom, a cyano group, a nitro group, a group represented by —P(═O)(R931)(R932), a group represented by —Ge(R933)(R934)(R935), a group represented by —B(R936)(R937), a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms; and the plurality of Ra are mutually the same or different.
In the formulae (3A) and (3B):
X1 is an oxygen atom, sulfur atom, CR301R302, or NR303;
a combination of R301 and R302 are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded;
at least one combination of adjacent two or more of R31 to R34 are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded;
at least one combination of adjacent two or more of R35 to R38 are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded;
at least one combination of adjacent two or more of R41 to R50 are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded;
R303, and R301, R302, R31 to R38 and R41 to R50 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring each independently represent the same as Ra in the formula (32); and any one of R301 to R303 and R31 to R38 in the formula (3A) is a single bond bonded to a nitrogen atom in the formula (31), a single bond bonded to a carbon atom in a six-membered ring in the formula (32), or a single bond bonded to a carbon atom in a six-membered ring in the formula (33); and any one of R41 to R50 in the formula (3B) is a single bond bonded to a nitrogen atom in the formula (31), a single bond bonded to a carbon atom in a six-membered ring in the formula (32), or a single bond bonded to a carbon atom in a six-membered ring in the formula (33).
In the first compound, R901, R902, R903, R904, R905, R906, R907, R908, R909, R931, R932, R933, R934, R935, R936, and R937 are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 ring carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms;
when a plurality of R901 are present, the plurality of R901 are mutually the same or different;
when a plurality of R902 are present, the plurality of R902 are mutually the same or different;
when a plurality of R903 are present, the plurality of R903 are mutually the same or different;
when a plurality of R904 are present, the plurality of R904 are mutually the same or different;
when a plurality of R905 are present, the plurality of R905 are mutually the same or different;
when a plurality of R906 are present, the plurality of R906 are mutually the same or different;
when a plurality of R907 are present, the plurality of R907 are mutually the same or different;
when a plurality of R908 are present, the plurality of R908 are mutually the same or different;
when a plurality of R909 are present, the plurality of R909 are mutually the same or different;
when a plurality of R931 are present, the plurality of R931 are mutually the same or different;
when a plurality of R932 are present, the plurality of R932 are mutually the same or different;
when a plurality of R933 are present, the plurality of R933 are mutually the same or different;
when a plurality of R934 are present, the plurality of R934 are mutually the same or different;
when a plurality of R935 are present, the plurality of R935 are mutually the same or different;
when a plurality of R936 are present, the plurality of R936 are mutually the same or different; and
when a plurality of R937 are present, the plurality of R937 are mutually the same or different.
The first compound is also preferably a compound represented by a formula (X) below.
In the formula (X):
Ar1 and Ar2 each independently represent the same as Ar1 and Ar2 in the formula (32);
at least one combination of adjacent two or more of a plurality of Ra are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded;
Ra forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring each independently represent the same as Ra forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring in the formula (32); and the plurality of Ra are mutually the same or different.
When the first compound is a compound represented by the formula (31), it is preferable that each Ar3 is independently a group represented by any of formulae (30A) to (30G) below.
When the first compound is a compound represented by the formula (32) or (33), it is preferable that each Ar3 is independently a group represented by any of formulae (30A) to (30H) below.
In the formulae (30A) to (30D), R301, R302, and R31 to R38 each independently represent the same as R301, R302, and R31 to R38 in the formula (3A); in the formulae (30E) to (30G), R41 to R50 each independently represent the same as R41 to R50 in the formula (3B); and in the formula (30H), R31 to R38 each independently represent the same as R31 to R38 in the formula (3A); and each * represents a bonding position.
In the first compound, it is preferable that Ar1 and Ar2 are each independently a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothienyl group, a substituted or unsubstituted fluorenyl group, a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted naphthyl group, or a substituted or unsubstituted phenanthrenyl group.
In the first compound, it is more preferable that Ar1 and Ar2 are each independently an unsubstituted phenyl group, an unsubstituted biphenyl group, an unsubstituted terphenyl group, an unsubstituted dibenzofuranyl group, an unsubstituted dibenzothienyl group, a substituted or unsubstituted fluorenyl group, a substituted or unsubstituted carbazolyl group, an unsubstituted naphthyl group, or an unsubstituted phenanthrenyl group.
The first compound is preferably a compound represented by any of formulae (301) to (310) below.
In the formulae (301) to (310):
X1 and R31 to R38 each independently represent the same as X1 and R31 to R38 in the formula (3A); each Ra independently represents the same as Ra in the formula (32);
at least one combination of adjacent two or more of R311 to R315 are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded;
at least one combination of adjacent two or more of R316 to R320 are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded;
R311 to R320 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring each independently represent the same as Ra in the formula (32);
each * represents a bonding position to a carbon atom in a six-membered ring having Ra; and
1* represents a bonding position to a carbon atom in a six-membered ring having Ra.
In the first compound, it is preferable that R31 to R38, R41 to R50, R301 to R303 and Ra are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms.
In the first compound, it is preferable that R31 to R38 and R41 to R50 are each independently a hydrogen atom, or a substituted or unsubstituted phenyl group.
In the first compound, it is preferable that R31 to R38 and R41 to R50 are each a hydrogen atom.
In the first compound, it is preferable that R301 to R303 are each independently a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms.
In the first compound, it is preferable that R301 and R302 are each independently a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms.
In the first compound, it is more preferable that R301 and R302 are each independently a methyl group, or a substituted or unsubstituted phenyl group.
In the first compound, it is also preferable that a combination of R301 and R302 are mutually bonded to form a substituted or unsubstituted monocyclic ring, or mutually bonded to form a substituted or unsubstituted fused ring.
In the first compound: it is preferable that each Ra is independently a hydrogen atom, an unsubstituted alkyl group having 1 to 50 carbon atoms, an unsubstituted aryl group having 6 to 50 ring carbon atoms, or an unsubstituted heterocyclic group having 5 to 50 ring atoms; and it is more preferable that each Ra is independently a hydrogen atom.
In the first compound, it is preferable that R311 to R320 are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms.
In the first compound, it is also preferable that at least one combination of adjacent two or more of R311 to R315 are mutually bonded to form a substituted or unsubstituted monocyclic ring, or mutually bonded to form a substituted or unsubstituted fused ring.
In the first compound, it is also preferable that at least one combination of adjacent two or more of R316 to R320 are mutually bonded to form a substituted or unsubstituted monocyclic ring, or mutually bonded to form a substituted or unsubstituted fused ring.
It is preferable that each substituent for the “substituted or unsubstituted” group for Ar1 and Ar2 is independently a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothienyl group, a substituted or unsubstituted fluorenyl group, a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted naphthyl group, or a substituted or unsubstituted phenanthrenyl group.
It is more preferable that each substituent for the “substituted or unsubstituted” group for Ar1 and Ar2 is independently an unsubstituted phenyl group, an unsubstituted biphenyl group, an unsubstituted dibenzofuranyl group, an unsubstituted dibenzothienyl group, a substituted or unsubstituted fluorenyl group, a substituted or unsubstituted carbazolyl group, an unsubstituted naphthyl group, or an unsubstituted phenanthrenyl group.
The first compound is also preferably a compound represented by a formula (10) below.
In the formula (10):
L10 is a single bond, or a substituted or unsubstituted arylene group having 6 to 12 ring carbon atoms;
a substituent, if present, for L10 is an unsubstituted phenyl group;
Ar10 is a substituted or unsubstituted aryl group having 6 to 18 ring carbon atoms; and a substituent, if present, for Ar10 is an unsubstituted phenyl group or an unsubstituted naphthyl group.
The compound represented by the formula (10) represents the same as a compound according to a sixth exemplary embodiment, and a preferable range thereof is also the same as that of the compound according to the sixth exemplary embodiment.
In the formula (10), L10 is preferably a single bond, or a substituted or unsubstituted phenylene group.
In the formula (10), Ar10 is preferably a group represented by any of formulae (10a) to (27a) below, and more preferably a group represented by any of the formulae (10a) to (14a), (17a), (18a), and (26a).
In the formula (10), Ar10 is further preferably a group represented by any of formulae (10a) to (13a), (14a-1) to (18a-1), (20a), (21a), and (26a-1) below.
Further, the compound represented by the formula (10) is also an exemplary arrangement of a compound represented by the formula (305).
In the first compound, it is preferable that each substituent for the “substituted or unsubstituted” group is independently the same as a substituent for the “substituted or unsubstituted” group in Ar1 and Ar2.
The ionization potential Ip(HT1) of the first compound satisfies the numerical formula (Numerical Formula 1) below.
The ionization potential Ip(HT1) of the first compound preferably satisfies a numerical formula (Numerical Formula 11) below. A method for measuring the ionization potential Ip is as described in Examples.
Ip(HT1)≥5.69 eV (Numerical Formula 1)
Ip(HT1)≥5.70 eV (Numerical Formula 11)
Hole Mobility μh(HT1) of First Compound
The hole mobility μh(HT1) of the first compound satisfies the numerical formula (Numerical Formula 2) below.
In an exemplary arrangement of the exemplary embodiment, the hole mobility μh(HT1) of the first compound satisfies a numerical formula (Numerical Formula 2A) below.
μh(HT1)≥1.00×10−5 cm2/Vs (Numerical Formula 2)
μh(HT1)≥1.00×10−4 cm2/Vs (Numerical Formula 2A)
Herein, the hole mobility can be measured according to an impedance measurement using a mobility evaluation device manufactured by the following steps. The mobility evaluation device is, for instance, manufactured by the following steps.
A compound HA-2 below is vapor-deposited on a glass substrate having an ITO transparent electrode (anode) so as to cover the transparent electrode, thereby forming a hole injecting layer. A compound HT-A below is vapor-deposited on this formed hole injecting layer to form a hole transporting layer. Subsequently, a compound Target, which is to be measured for a hole mobility, is vapor-deposited to form a measurement target layer. Metal aluminum (Al) is vapor-deposited on this measurement target layer to form a metal cathode.
An arrangement of the mobility evaluation device above is roughly shown as follows.
ITO(130)/HA-2(5)/HT-A(10)/Target(200)/Al(80)
Numerals in parentheses represent a film thickness (nm).
The mobility evaluation device for the hole mobility is set in an impedance measurement device to perform an impedance measurement. In the impedance measurement, a measurement frequency is swept from 1 Hz to 1 MHz. At this time, an alternating current amplitude of 0.1 V and a direct current voltage V are applied to the device. A modulus M is calculated from a measured impedance Z using the relationship of the calculation formula (C1).
In a bode plot in which an imaginary part of the modulus M is represented by an ordinate axis and the frequency [Hz] is represented by an abscissa axis, an electrical time constant τ of the mobility evaluation device is obtained from a frequency fmax showing a peak using the calculation formula (C2).
A hole mobility μh is calculated from a relationship of a calculation formula (C3-2) below using τ obtained from the calculation formula (C2).
μh=d2/(Vτ) Calculation Formula (C3-2):
d in the calculation formula (C3-2) is a total film thickness of organic thin film(s) forming the device. In a case of the arrangement of the mobility evaluation device for the hole mobility, d=215 [nm] is satisfied.
The hole mobility herein is a value obtained in a case where a square root of an electric field intensity meets E1/2=500 [V1/2/cm1/2]. The square root of the electric field intensity, E1/2, can be calculated from a relationship of a calculation formula (C4) below.
E
1/2
=V
1/2
/d
1/2 Calculation Formula (C4):
For the impedance measurement, a 1260 type by Solartron Analytical is used as the impedance measurement device, and for a higher accuracy, a 1296 type dielectric constant measurement interface by Solartron Analytical can be used together therewith.
The first compound can be manufactured by a known method.
Specific examples of the first compound include the following compounds.
It should however be noted that the invention is not limited to the specific examples of the compound.
The second layer contains the second compound.
The second compound may be any compound having an ionization potential Ip(HT2) of 5.60 eV or more (Numerical Formula 3).
The second compound is preferably an amine compound.
As the second compound, for instance, a compound having an ionization potential Ip(HT2) of 5.60 eV or more can be selected for use from compounds represented by the formulae (31) to (33) and the formula (X).
The description of the formulae (31) to (33) and the formula (X) for the first compound can be applied to the second compound.
The ionization potential Ip(HT2) of the second compound satisfies the numerical formula (Numerical Formula 3) below. The ionization potential Ip(HT2) of the second compound preferably satisfies a numerical formula (Numerical Formula 31) below.
Ip(HT2)≥5.60 eV (Numerical Formula 3)
Ip(HT2)≥5.65 eV (Numerical Formula 31)
Hole Mobility μh(HT2) of Second Compound
In an exemplary arrangement of the exemplary embodiment, the hole mobility μh(HT2) of the second compound satisfies a numerical formula (Numerical Formula 33) below.
In an exemplary arrangement of the exemplary embodiment, the hole mobility μh(HT2) of the second compound satisfies a numerical formula (Numerical Formula 33A) below.
μh(HT2)≥1.00×10−5 cm2/Vs (Numerical Formula 33)
μh(HT2)≥1.00×10−4 cm2/Vs (Numerical Formula 33A)
The second compound can be manufactured by a known method.
Specific Examples of Second Compound Specific examples of the second compound include the following compounds.
It should however be noted that the invention is not limited to the specific examples of the compound.
The emitting layer of the first exemplary embodiment at least contains a delayed fluorescent compound.
An arrangement of the first exemplary embodiment, in which the emitting layer contains a fluorescent compound M1 and a compound M2 as the delayed fluorescent compound, is explained below.
The emitting layer of the organic EL device according to the exemplary embodiment contains the fluorescent compound M1 and the compound M2 as the delayed fluorescent compound.
In this arrangement, the compound M2 is preferably a host material (occasionally also referred to as a matrix material). The compound M1 is preferably a dopant material (occasionally also referred to as a guest material, emitter or luminescent material).
Delayed fluorescence is explained in “Yuki Hando-tai no Debaisu Bussei (Device Physics of Organic Semiconductors)” (edited by ADACHI, Chihaya, published by Kodansha, on pages 261-268). This document describes that, if an energy difference ΔE13 of a fluorescent material between a singlet state and a triplet state is reducible, a reverse energy transfer from the triplet state to the singlet state, which usually occurs at a low transition probability, would occur at a high efficiency to express thermally activated delayed fluorescence (TADF). Further, a mechanism of generating delayed fluorescence is explained in
In general, emission of delayed fluorescence can be confirmed by measuring the transient PL (Photo Luminescence).
The behavior of delayed fluorescence can also be analyzed based on the decay curve obtained from the transient PL measurement. The transient PL measurement is a method of irradiating a sample with a pulse laser to excite the sample, and measuring the decay behavior (transient characteristics) of PL emission after the irradiation is stopped. PL emission in TADF materials is classified into a light emission component from a singlet exciton generated by the first PL excitation and a light emission component from a singlet exciton generated via a triplet exciton. The lifetime of the singlet exciton generated by the first PL excitation is on the order of nanoseconds and is very short. Therefore, light emission from the singlet exciton rapidly attenuates after irradiation with the pulse laser.
On the other hand, the delayed fluorescence is gradually attenuated due to light emission from a singlet exciton generated via a triplet exciton having a long lifetime. As described above, there is a large temporal difference between the light emission from the singlet exciton generated by the first PL excitation and the light emission from the singlet exciton generated via the triplet exciton. Therefore, the luminous intensity derived from delayed fluorescence can be determined.
A transient PL measuring device 100 in
The sample housed in the sample chamber 102 is obtained by forming a thin film, in which a matrix material is doped with a doping material at a concentration of 12 mass %, on the quartz substrate.
The thin film sample housed in the sample chamber 102 is irradiated with the pulse laser from the pulse laser 101 to excite the doping material. Emission is extracted in a direction of 90 degrees with respect to a radiation direction of the excited light. The extracted emission is divided by the spectrometer 103 to form a two-dimensional image in the streak camera 104. As a result, the two-dimensional image is obtainable in which the ordinate axis represents a time, the abscissa axis represents a wavelength, and a bright spot represents a luminous intensity. When this two-dimensional image is taken out at a predetermined time axis, an emission spectrum in which the ordinate axis represents the luminous intensity and the abscissa axis represents the wavelength is obtainable. Moreover, when this two-dimensional image is taken out at the wavelength axis, a decay curve (transient PL) in which the ordinate axis represents a logarithm of the luminous intensity and the abscissa axis represents the time is obtainable.
For instance, a thin film sample A was prepared as described above from a reference compound H1 as the matrix material and a reference compound D1 as the doping material and was measured in terms of the transient PL.
The decay curve was analyzed with respect to the above thin film sample A and a thin film sample B. The thin film sample B was manufactured in the same manner as described above from a reference compound H2 as the matrix material and the reference compound D1 as the doping material.
As described above, an emission decay curve in which the ordinate axis represents the luminous intensity and the abscissa axis represents the time can be obtained by the transient PL measurement. Based on the emission decay curve, a fluorescence intensity ratio between fluorescence emitted from a singlet state generated by photo-excitation and delayed fluorescence emitted from a singlet state generated by inverse energy transfer via a triplet state can be estimated. In a delayed fluorescent material, a ratio of the intensity of the slowly decaying delayed fluorescence to the intensity of the promptly decaying fluorescence is relatively large.
Specifically, Prompt emission and Delay emission are present as emission from the delayed fluorescent material. Prompt emission is observed promptly when the excited state is achieved by exciting the compound of the exemplary embodiment with a pulse beam (i.e., a beam emitted from a pulse laser) having a wavelength absorbable by the delayed fluorescent material. Delay emission is observed not promptly when the excited state is achieved but after the excited state is achieved.
An amount of Prompt emission, an amount of Delay emission and a ratio between the amounts thereof can be obtained according to the method as described in “Nature 492, 234-238, 2012” (Reference Document 1). The amount of Prompt emission and the amount of Delay emission may be calculated using a device different from one described in Reference Document 1 or one shown in
Herein, a sample manufactured by the following method is used for measuring delayed fluorescence of the compound M2. For instance, the compound M2 is dissolved in toluene to prepare a dilute solution with an absorbance of 0.05 or less at the excitation wavelength to eliminate the contribution of self-absorption. In order to prevent quenching due to oxygen, the sample solution is frozen and degassed and then sealed in a cell with a lid under an argon atmosphere to obtain an oxygen-free sample solution saturated with argon.
The fluorescence spectrum of the sample solution is measured with a spectrofluorometer FP-8600 (manufactured by JASCO Corporation), and the fluorescence spectrum of a 9,10-diphenylanthracene ethanol solution is measured under the same conditions. Using the fluorescence area intensities of both spectra, the total fluorescence quantum yield is calculated by an equation (1) in Morris et al. J. Phys. Chem. 80 (1976) 969.
In the exemplary embodiment, provided that an amount of Prompt emission of a measurement target compound (compound M2) is denoted by XP and the amount of Delay emission is denoted by XD, a value of XD/XP is preferably 0.05 or more.
The amounts of Prompt emission and Delay emission and a ratio of the amounts thereof in compounds other than the compound M2 herein are measured in the same manner as those of the compound M2.
In the formula (2):
n is 1, 2, 3 or 4;
m is 1, 2, 3 or 4;
q is 0, 1, 2, 3 or 4;
m+n+q=6 is satisfied;
CN is a cyano group;
D1 is a group represented by a formula (2a), (2b) or (2c) below, and when a plurality of D1 are present, the plurality of D1 are mutually the same or different; Rx is a hydrogen atom or a substituent, or at least one combination of adjacent ones of Rx are mutually bonded to form a ring, and when a plurality of Rx are present, the plurality of Rx are mutually the same or different;
each Rx as a substituent is independently a halogen atom, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted carbonyl group, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 30 carbon atoms, or a substituted or unsubstituted arylsilyl group having 6 to 60 ring carbon atoms; and
CN, D1 and Rx are bonded to respective carbon atoms of a six-membered ring.
In the formula (2a):
R1 to R8 are each independently a hydrogen atom or a substituent, or at least one combination of a combination of R1 and R2, a combination of R2 and R3, a combination of R3 and R4, a combination of R5 and R6, a combination of R6 and R7, or a combination of R7 and R8 are mutually bonded to form a ring;
R1 to R8 as a substituent are each independently a halogen atom, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 30 carbon atoms, a substituted or unsubstituted arylsilyl group having 6 to 60 ring carbon atoms, a hydroxy group, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy halide group having 1 to 30 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, a substituted or unsubstituted alkylamino group having 2 to 30 carbon atoms, a substituted or unsubstituted arylamino group having 6 to 60 ring carbon atoms, a thiol group, a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms; and
* represents a bonding position to a carbon atom in a six-membered ring in the formula (2).
In the formula (2b):
R21 to R28 are each independently a hydrogen atom or a substituent, or at least one combination of a combination of R21 and R22, a combination of R22 and R23, a combination of R23 and R24, a combination of R25 and R26, a combination of R26 and R27, or a combination of R27 and R28 are mutually bonded to form a ring;
R21 to R28 as a substituent each independently represent the same as R1 to R8 in the formula (2a);
A represents a cyclic structure represented by a formula (211) or (212) below, and the cyclic structure A is fused with adjacent cyclic structure(s) at any position(s);
p is 1, 2, 3 or 4;
when p is 2, 3 or 4, a plurality of cyclic structures A are mutually the same or different; and
* represents a bonding position to a carbon atom in a six-membered ring in the formula (2).
In the formula (2c):
R2001 to R2008 are each independently a hydrogen atom or a substituent, or at least one combination of a combination of R2001 and R2002, a combination of R2002 and R2003, a combination of R2003 and R2004, a combination of R2005 and R2006, a combination of R2006 and R2007, or a combination of R2007 and R2008 are mutually bonded to form a ring;
R2001 to R2008 as a substituent each independently represent the same as R1 to R8 as a substituent in the formula (2a);
B represents a cyclic structure represented by the formula (211) or (212), and the cyclic structure B is fused with adjacent cyclic structure(s) at any position(s);
px is 1, 2, 3 or 4;
when px is 2, 3 or 4, a plurality of cyclic structures B are mutually the same or different;
C represents a cyclic structure represented by the formula (211) or (212), and the cyclic structure C is fused with adjacent cyclic structure(s) at any position(s);
py is 1, 2, 3 or 4;
when py is 2, 3 or 4, a plurality of cyclic structures C are mutually the same or different; and
* represents a bonding position to a carbon atom in a six-membered ring in the formula (2).
In the formula (211), R2009 and R2010 are each independently a hydrogen atom or a substituent, or bonded to a part of an adjacent cyclic structure to form a ring, or a combination of R2009 and R2010 are mutually bonded to form a ring;
in the formula (212), X201 is CR2011R2012, NR2013, a sulfur atom, or an oxygen atom, and R2011, R2012 and R2013 are each independently a hydrogen atom or a substituent, or R2011 and R2012 are mutually bonded to form a ring; and
R2009, R2010, R2011, R2012 and R2013 as a substituent each independently represent the same as R1 to R8 as a substituent in the formula (2a).
In the formula (211), R2009 and R2010 are each independently bonded to a part of an adjacent cyclic structure to form a ring, which specifically means any of (I) to (IV) below.
In the formula (211), a combination of R2009 and R2010 are mutually bonded to form a ring, which specifically means (V) below.
(I) When the cyclic structures represented by the formula (211) are adjacent to each other, between the two adjacent rings, at least one combination of the following are mutually bonded to form a ring: R2009 of one of the rings and R2009 of the other of the rings; R2009 of one of the rings and R2010 of the other of the rings; or R2010 of one of the rings and R2010 of the other of the rings.
(II) When the cyclic structure represented by the formula (211) and the benzene ring having R25 to R28 in the formula (2b) are adjacent to each other, between the two adjacent rings, at least one combination of the following are mutually bonded to form a ring: R2009 of one of the rings and R25 of the other of the rings; R2009 of one of the rings and R28 of the other of the rings; R2010 of one of the rings and R25 of the other of the rings; or R2010 of one of the rings and R28 of the other of the rings.
(III) When the cyclic structure represented by the formula (211) and the benzene ring having R2001 to R2004 in the formula (2c) are adjacent to each other, between the two adjacent rings, at least one combination of the following are mutually bonded to form a ring: R2009 of one of the rings and R2001 of the other of the rings; R2009 of one of the rings and R2004 of the other of the rings; R2010 of one of the rings and R2001 of the other of the rings; or R2010 of one of the rings and R2004 of the other of the rings.
(IV) When the cyclic structure represented by the formula (211) and the benzene ring having R2005 to R2008 in the formula (2c) are adjacent to each other, between the two adjacent rings, at least one combination of the following are mutually bonded to form a ring: R2009 of one of the rings and R2005 of the other of the rings; R2009 of one of the rings and R2008 of the other of the rings; R2010 of one of the rings and R2005 of the other of the rings; or R2010 of one of the rings and R2008 of the other of the rings.
(V) The combination of R2009 and R2010 of the cyclic structure represented by the formula (211) are mutually bonded to form a ring. In other words, (V) means that the combination of R2009 and R2010, which are bonded to the same ring, are mutually bonded to form a ring.
In the compound M2 of the exemplary embodiment, it is preferable that:
each Rx is independently a hydrogen atom, an unsubstituted aryl group having 6 to 30 ring carbon atoms, an unsubstituted heterocyclic group having 5 to 30 ring atoms, or an unsubstituted alkyl group having 1 to 30 carbon atoms; and
when Rx is an unsubstituted heterocyclic group having 5 to 30 ring atoms, Rx as the unsubstituted heterocyclic group having 5 to 30 ring atoms is a pyridyl group, pyrimidinyl group, triazinyl group, dibenzofuranyl group, or dibenzothienyl group.
Herein, the triazinyl group refers to a group obtained by excluding one hydrogen atom from 1,3,5-triazine, 1,2,4-triazine, or 1,2,3-triazine.
The triazinyl group is preferably a group obtained by excluding one hydrogen atom from 1,3,5-triazine.
In the compound M2 of the exemplary embodiment, it is more preferable that each Rx is independently a hydrogen atom, an unsubstituted aryl group having 6 to 30 ring carbon atoms, an unsubstituted dibenzofuranyl group, or an unsubstituted dibenzothienyl group.
In the compound M2 of the exemplary embodiment, Rx is further preferably a hydrogen atom.
In the compound M2 of the exemplary embodiment, it is preferable that R1 to R8, R21 to R28, R2001 to R2008, R2009 to R2010 and R2011 to R2013 as a substituent are each independently an unsubstituted aryl group having 6 to 30 ring carbon atoms, an unsubstituted heterocyclic group having 5 to 30 ring atoms, or an unsubstituted alkyl group having 1 to 30 carbon atoms.
In the compound M2 of the exemplary embodiment, D1 is preferably a group represented by one of formulae (D-21) to (D-27) below.
In the formula (D-21), R83 to R90 are each independently a hydrogen atom or a substituent;
in the formulae (D-22) to (D-27): X1 to X6 are each independently an oxygen atom, a sulfur atom, or CR151R152;
R151 and R152 are each independently a hydrogen atom or a substituent, or R151 and R152 are bonded to each other to form a ring;
R201 to R260 are each independently a hydrogen atom or a substituent, or at least one combination of a combination of R201 and R202, a combination of R202 and R203, a combination of R203 and R204, a combination of R205 and R206, a combination of R207 and R208, a combination of R208 and R209, a combination of R209 and R210, a combination of R211 and R212, a combination of R212 and R213, a combination of R213 and R214, a combination of R216 and R217, a combination of R217 and R218, a combination of R218 and R219, a combination of R221 and R222, a combination of R222 and R223, a combination of R223 and R224, a combination of R226 and R227, a combination of R227 and R228, a combination of R228 and R229, a combination of R231 and R232, a combination of R232 and R233, a combination of R233 and R234, a combination of R235 and R236, a combination of R236 and R237, a combination of R237 and R238, a combination of R239 and R240, a combination of R241 and R242, a combination of R242 and R243, a combination of R243 and R244, a combination of R245 and R246, a combination of R246 and R247, a combination of R247 and R248, a combination of R249 and R250, a combination of R251 and R252, a combination of R252 and R253, a combination of R253 and R254, a combination of R255 and R256, a combination of R257 and R258, a combination of R258 and R259, or a combination of R259 and R260 are bonded to each other to form a ring;
R83 to R90, R151, R152 and R201 to R260 as a substituent are each independently a halogen atom, a substituted or unsubstituted aryl group having 6 to 14 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 14 ring atoms, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 8 ring carbon atoms, a substituted or unsubstituted alkylsilyl group having 3 to 6 carbon atoms, a hydroxy group, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy halide group having 1 to 6 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 14 ring carbon atoms, a substituted or unsubstituted arylamino group having 6 to 28 ring carbon atoms, a substituted or unsubstituted alkylamino group having 2 to 12 carbon atoms, a thiol group, a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms, or a substituted or unsubstituted arylthio group having 6 to 14 ring carbon atoms; and
* represents a bonding position to a carbon atom in a six-membered ring in the formula (2).
In the compound M2 of the exemplary embodiment, D1 is also more preferably a group represented by formula (D-21), (D-23), (D-24), or (D-25).
In the compound M2 of the exemplary embodiment, D1 is also further preferably a group represented by formula (D-21), (D-23), or (D-25).
In the compound M2 of the exemplary embodiment, R83 to R90, R201 to R260, R151 and R152 are preferably each independently a hydrogen atom, an unsubstituted aryl group having 6 to 14 ring carbon atoms, an unsubstituted heterocyclic group having 5 to 14 ring atoms, or an unsubstituted alkyl group having 1 to 6 carbon atoms.
In the compound M2 of the exemplary embodiment, R83 to R90 and R201 to R260 are each preferably a hydrogen atom.
In the compound M2 of the exemplary embodiment, R151 and R152 are preferably each independently an unsubstituted aryl group having 6 to 14 ring carbon atoms, an unsubstituted heterocyclic group having 5 to 14 ring atoms, or an unsubstituted alkyl group having 1 to 6 carbon atoms.
In the formula (22), Ar1 is a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group, a cyano group, a nitro group, a carboxy group, and groups represented by formulae (1a) to (1j) below.
In the formula (22), ArEWG is a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms that includes at least one nitrogen atom in a ring, or an aryl group having 6 to 30 ring carbon atoms that is substituted by at least one cyano group.
In the formula (22), each Arx is independently a hydrogen atom or a substituent, and Arx as a substituent is a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group, a cyano group, a nitro group, a carboxy group, and groups represented by the formulae (1a) to (1j).
In the formula (22), n is 0, 1, 2, 3, 4 or 5, and when n is 2, 3, 4 or 5, a plurality of Arx are mutually the same or different.
In the formula (22), a ring (A) is a substituted or unsubstituted aromatic hydrocarbon ring or a substituted or unsubstituted heterocycle, and the ring (A) is a five-membered ring, a six-membered ring, or a seven-membered ring. The ring (A) may be an aromatic hydrocarbon ring or a heterocycle. Ar1 and Arx are bonded to respective ones of elements forming the ring (A).
In the formula (22), at least one of Ar1 or Arx is a group selected from the group consisting of groups represented by the formulae (1a) to (1j).
In the formulae (1a) to (1j), X1 to X20 are each independently a nitrogen atom (N) or a carbon atom bonded with RA1 (C—RA1)
In the formula (1 b), one of X5 to X5 is a carbon atom bonded to one of X9 to X12, and one of X9 to X12 is a carbon atom bonded to one of X5 to X8.
In the formula (1c), one of X5 to X8 is a carbon atom bonded to a nitrogen atom in a ring including A2.
In the formula (1e), one of X5 to X8 and X18 is a carbon atom bonded to one of X9 to X12, and one of X9 to X12 is a carbon atom bonded to one of X5 to X8 and X18.
In the formula (1f), one of X5 to X8 and X18 is a carbon atom bonded to one of X9 to X12 and X19, and one of X9 to X12 and X19 is a carbon atom bonded to one of X5 to X8 and X18.
In the formula (1g), one of X5 to X8 is a carbon atom bonded to one of X9 to X12 and X19, and one of X9 to X12 and X19 is a carbon atom bonded to one of X5 to X8.
In the formula (1h), one of X5 to X8 and X18 is a carbon atom bonded to a nitrogen atom in a ring including A2.
In the formula (1i), one of X5 to X8 and X18 is a carbon atom bonded to a nitrogen atom that links a ring including X9 to X12 and X19 with a ring including X13 to X16 and X20.
In the formula (1j), one of X5 to X8 is a carbon atom bonded to a nitrogen atom that links a ring including X9 to X12 and X19 with a ring including X13 to X16 and X20.
each RA1 is independently a hydrogen atom or a substituent, or at least one combination of combinations of a plurality of RA1 are mutually directly bonded to form a ring or bonded via a hetero atom to form a ring; and
RA1 as a substituent is a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group, a cyano group, a nitro group, and a carboxy group.
When a plurality of RA1 as a substituent are present, the plurality of RA1 are mutually the same or different.
In the formula (1a), when X1 to X8 are each a carbon atom bonded with RA1 (C—RA1), a plurality of RA1 preferably form no ring.
In the formulae (1a) to (1j), * represents a bonding position to the ring (A).
In the formulae (1a) to (1j), A1 and A2 are each independently a single bond, an oxygen atom (O), a sulfur atom (S), C(R2021)(R2022), Si(R2023)(R2024), C(═O), S(═O), SO2 or N(R2025). R2021 to R2025 are each independently a hydrogen atom or a substituent, and R2021 to R2025 as a substituent are each independently a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group, a cyano group, a nitro group, and a carboxy group.
In the formulae (1a) to (1j), Ara is a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, and a substituted silyl group. Ara is preferably a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms or a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms.
The formula (1a) is represented by a formula (1aa) below when A1 is a single bond, represented by a formula (1ab) below when A1 is 0, represented by a formula (1ac) below when A1 is S, represented by a formula (1ad) below when A1 is C(R2021)(R2022), represented by a formula (1ae) below when A1 is Si(R2023)(R2024), represented by a formula (1af) below when A1 is C(═O), represented by a formula (1ag) below when A1 is S(═O), represented by a formula (1ah) below when A1 is SO2, and represented by a formula (1ai) below when A1 is N(R2025). In the formulae (1aa) to (1ai), X1 to X8 and R2021 to R2025 represent the same as described above. Linkages between rings via A1 and A2 in the formulae (1b), (1c), (1e) and (1g) to (1j) are the same as those in the formulae (1aa) to (1ai). In the formula (1aa), when X1 to X8 are each a carbon atom bonded with RA1 (C—RA1), a plurality of RA1 as a substituent preferably form no ring.
The compound M2 is preferably represented by a formula (221) below.
Art ArEWG, Arx, n and a ring (A) in the formula (221) respectively represent the same as Art ArEWG, Arx, n and the ring (A) in the formula (22).
The compound M2 is also preferably represented by a formula (222) below.
In the formula (222), Y1 to Y5 are each independently a nitrogen atom (N), a carbon atom bonded with a cyano group (C—CN), or a carbon atom bonded with RA2 (C—RA2), and at least one of Y1 to Y5 is N or C—CN. A plurality of RA2 are mutually the same or different. RA2 are each independently a hydrogen atom or a substituent, RA2 as a substituent being a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group, a cyano group, a nitro group, and a carboxy group; and
a plurality of RA2 are mutually the same or different.
In the formula (222), Ar1 represents the same as Ar1 in the formula (22).
In the formula (222), Ar2 to Ar5 are each independently a hydrogen atom or a substituent, and Ar2 to Ar5 as a substituent are each independently a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group, a cyano group, a nitro group, a carboxy group, and groups represented by the formulae (1a) to (1c).
In the formula (222), at least one of Ar1 to Ar5 is a group selected from the group consisting of groups represented by the formulae (1a) to (1c).
The compound M2 is also preferably a compound represented by a formula (11aa), (11bb) or (11cc) below.
In the formulae (11aa), (11bb) and (11cc), Y1 to Y5, RA2, Ar2 to Ar5, X1 to X16, RA1 and Ara respectively represent the same as the above-described Y1 to Y5, RA2, Ar2 to Ary, X1 to X16, RA1 and Ara.
The compound M2 is exemplified by a compound represented by a formula (23) below.
In the formula (23):
Az is a cyclic structure selected from the group consisting of a substituted or unsubstituted pyridine ring, a substituted or unsubstituted pyrimidine ring, a substituted or unsubstituted triazine ring, and a substituted or unsubstituted pyrazine ring;
c is 0, 1, 2, 3, 4 or 5;
when c is 0, Cz and Az are bonded by a single bond;
when c is 1, 2, 3, 4 or 5, L23 is a linking group selected from the group consisting of a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms, and a substituted or unsubstituted heteroarylene group having 5 to 30 ring atoms;
when c is 2, 3, 4 or 5, a plurality of L23 are mutually the same or different;
the plurality of L23 are mutually bonded to form a ring or not bonded to form no ring; and
Cz is represented by a formula (23a) below.
In the formula (23a):
Y21 to Y28 are each independently a nitrogen atom or CRA3;
each RA3 is independently a hydrogen atom or a substituent, or at least one combination of combinations among a plurality of RA3 are mutually bonded to form a ring;
each RA3 as a substituent is independently a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group, a cyano group, a nitro group, and a carboxy group;
a plurality of RA3 are mutually the same or different; and
*1 represents a bonding position to a carbon atom in a structure of a linking group represented by L23, or a bonding position to a carbon atom in a cyclic structure represented by Az.
Y21 to Y28 are also preferably CRA3.
c in the formula (23) is preferably 0 or 1.
Cz is also preferably represented by a formula (23b), (23c) or (23d) below.
In the formulae (23b), (23c) and (23d), Y21 to Y28 and Y51 to Y58 are each independently a nitrogen atom or CRA4;
in the formula (23b), at least one of Y25 to Y28 is a carbon atom bonded to one of Y51 to Y54, and at least one of Y51 to Y54 is a carbon atom bonded to one of Y25 to Y28;
in the formula (23c), at least one of Y25 to Y28 is a carbon atom bonded to a nitrogen atom in a five-membered ring of a nitrogen-containing fused ring including Y51 to Y58;
in the formula (23d), *a and *b each represent a bonding position to one of Y21 to Y28, at least one of Y25 to Y28 is the bonding position represented by *a, and at least one of Y25 to Y28 is the bonding position represented by *b;
n is 1, 2, 3 or 4;
each RA4 is independently a hydrogen atom or a substituent, or at least one combination of combinations among a plurality of RA4 are mutually bonded to form a ring;
each RA4 as a substituent is independently a substituent selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group, a cyano group, a nitro group, and a carboxy group;
a plurality of RA4 are mutually the same or different;
Z21 and Z22 are each independently any one selected from the group consisting of an oxygen atom, a sulfur atom, NR45 and CR46R47;
R45 is a hydrogen atom or a substituent;
R46 and R47 are each independently a hydrogen atom or a substituent, or a combination of R46 and R47 are mutually bonded to form a ring;
R45, R46 and R47 as a substituent are each independently a substituent selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted fluoroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted phosphoryl group, a substituted silyl group, a cyano group, a nitro group, and a carboxy group;
a plurality of R45 are mutually the same or different;
a plurality of R46 are mutually the same or different;
a plurality of R47 are mutually the same or different; and
* represents a bonding position to a carbon atom in a structure of a linking group represented by L23, or a bonding position to a carbon atom in a cyclic structure represented by Az.
Z21 is preferably NR45.
When Z21 is NR45, R45 is preferably a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.
Z22 is preferably NR45.
When Z22 is NR45, R45 is preferably a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.
Y51 to Y58 are preferably CRA4, provided that at least one of Y51 to Y58 is a carbon atom bonded to a cyclic structure represented by the formula (23a).
It is also preferable that Cz is represented by the formula (23d) and n is 1.
Az is preferably a cyclic structure selected from the group consisting of a substituted or unsubstituted pyrimidine group and a substituted or unsubstituted triazine group.
Az is a cyclic structure selected from the group consisting of a substituted pyrimidine ring and a substituted triazine ring, in which a substituent of each of the substituted pyrimidine ring and the substituted triazine ring is more preferably a group selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms and a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, further preferably a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms.
When the pyrimidine ring and the triazine ring as Az have a substituted or unsubstituted aryl group as a substituent, the aryl group preferably has 6 to 20 ring carbon atoms, more preferably 6 to 14 ring carbon atoms, further preferably 6 to 12 ring carbon atoms.
When Az has a substituted or unsubstituted aryl group as a substituent, the substituent is preferably a group selected from the group consisting of a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted phenanthryl group, a substituted or unsubstituted terphenyl group, and a substituted or unsubstituted fluorenyl group, more preferably a group selected from the group consisting of a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, and a substituted or unsubstituted naphthyl group.
When Az has a substituted or unsubstituted heteroaryl group as a substituent, the substituent is preferably a substituent selected from the group consisting of a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted dibenzofuranyl group, and a substituted or unsubstituted dibenzothiophenyl group.
It is preferable that each RA4 is independently a hydrogen atom or a substituent, and RA4 as a substituent is a substituent selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms and a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms.
When RA4 as a substituent is a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, RA4 as a substituent is preferably a substituent selected from the group consisting of a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted phenanthryl group, a substituted or unsubstituted terphenyl group, and a substituted or unsubstituted fluorenyl group, more preferably a substituent selected from the group consisting of a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, and a substituted or unsubstituted naphthyl group.
When RA4 as a substituent is a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, RA4 as a substituent is preferably a substituent selected from the group consisting of a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted dibenzofuranyl group, and a substituted or unsubstituted dibenzothiophenyl group.
R45, R46 and R47 as a substituent are preferably each independently a substituent selected from the group consisting of a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, and a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms.
The compound M2 can be manufactured by a known method.
Specific examples of the compound M2 include the following compounds. It should however be noted that the invention is not limited to the specific examples of the compound.
The compound M1 of the exemplary embodiment is not a phosphorescent metal complex. The compound M1 is preferably not a heavy metal complex. Further, the compound M1 is preferably not a metal complex.
Further, the compound M1 is preferably a compound exhibiting no thermally activated delayed fluorescence.
A fluorescent material is usable as the compound M1. Specific examples of the fluorescent material include a bisarylaminonaphthalene derivative, aryl-substituted naphthalene derivative, bisarylaminoanthracene derivative, aryl-substituted anthracene derivative, bisarylaminopyrene derivative, aryl-substituted pyrene derivative, bisarylamino chrysene derivative, aryl-substituted chrysene derivative, bisarylaminofluoranthene derivative, aryl-substituted fluoranthene derivative, indenoperylene derivative, acenaphthofluoranthene derivative, compound including a boron atom, pyromethene boron complex compound, compound having a pyromethene skeleton, metal complex of the compound having a pyrromethene skeleton, diketopyrrolopyrrole derivative, perylene derivative, and naphthacene derivative.
In the exemplary embodiment, the compound M1 that fluoresces is preferably a compound represented by a formula (20) below.
In the formula (20):
X is a nitrogen atom, or a carbon atom bonded to Y;
Y is a hydrogen atom or a substituent;
R21 to R26 are each independently a hydrogen atom or a substituent, or at least one of a combination of R21 and R22, a combination of R22 and R23, a combination of R24 and R25, or a combination of R25 and R26 are mutually bonded to form a ring;
Y and R21 to R26 as a substituent are each independently selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy halide group having 1 to 30 carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms, a substituted or unsubstituted arylthio group having 6 to 30 ring carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 5 to 30 ring atoms, a halogen atom, a carboxy group, a substituted or unsubstituted ester group, a substituted or unsubstituted carbamoyl group, a substituted or unsubstituted amino group, a nitro group, a cyano group, a substituted or unsubstituted silyl group, and a substituted or unsubstituted siloxanyl group;
Z21 and Z22 are each independently a substituent, or are mutually bonded to form a ring; and
Z21 and Z22 as a substituent are each independently selected from the group consisting of a halogen atom, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkyl halide group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, a substituted or unsubstituted alkoxy halide group having 1 to 30 carbon atoms, and a substituted or unsubstituted aryloxy group having 6 to 30 ring carbon atoms.
In the exemplary embodiment, the fluorescent compound M1 is also preferably a compound represented by a formula (1) below.
In the formula (1):
a ring A, ring B, ring D, ring E, and ring F are each independently a cyclic structure selected from the group consisting of a substituted or unsubstituted aryl ring having 6 to 30 ring carbon atoms and a substituted or unsubstituted heterocycle having 5 to 30 ring atoms;
one of the ring B and the ring D is present or both of the ring B and the ring D are present;
when both of the ring B and the ring D are present, the ring B and the ring D share a bond between Zc and Zh;
one of the ring E and the ring F is present or both of the ring E and the ring F are present;
when both of the ring E and the ring F are present, the ring E and the ring F share a bond between Zf and Zi;
Za is a nitrogen atom or a carbon atom;
Zb is a nitrogen atom or a carbon atom when the ring B is present;
Zb is an oxygen atom, a sulfur atom, NRb, C(Rb1)(Rb2), or Si(Rb3)(Rb4) when the ring B is not present;
Zc is a nitrogen atom or a carbon atom;
Zd is a nitrogen atom or a carbon atom when the ring D is present;
Zd is an oxygen atom, a sulfur atom, or NRd when the ring D is not present;
Ze is a nitrogen atom or a carbon atom when the ring E is present;
Ze is an oxygen atom, a sulfur atom, or NRe when the ring E is not present;
Zf is a nitrogen atom or a carbon atom;
Zg is a nitrogen atom or a carbon atom when the ring F is present;
Zg is an oxygen atom, a sulfur atom, NRg, C(Rg1)(Rg2), or Si(Rg3)(Rg4) when the ring F is not present;
Zh is a nitrogen atom or a carbon atom;
Zi is a nitrogen atom or a carbon atom;
Y is a boron atom, a phosphorus atom, SiRh, P═O or P═S;
Rb, Rb1, Rb2, Rb3, Rb4, Rd, Re, Rg, Rg1, Rg2, Rg3, Rg4, and Rh are each independently a hydrogen atom or a substituent;
Rb, Rb1, Rb2, Rb3, Rb4, Rd, Re, Rg, Rg1, Rg2, Rg3, Rg4, and Rh as a substituent are each independently a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 ring atoms, a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 30 ring carbon atoms, a group represented by —Si(R911)(R912)(R913), a group represented by —O—(R914), a group represented by —S—(R915), or a group represented by —N(R916)(R917);
a bond between Y and Za, a bond between Y and Zd, and a bond between Y and Ze are each a single bond; and
a bond between Y and Za, a bond between Y and Zd, and a bond between Y and Ze are each a single bond, where the single bond is not a coordinate bond but a covalent bond.
Herein, examples of a heterocycle include cyclic structures (heterocycles) excluding a bond from the examples of a “heterocyclic group” listed in the subtitle “Substituents Mentioned Herein.” These heterocycles may be substituted or unsubstituted.
Herein, examples of an aryl ring include cyclic structures (aryl rings) excluding a bond from the examples of an “aryl group” listed in the subtitle “Substituents Mentioned Herein.” These aryl rings may be substituted or unsubstituted.
In the exemplary embodiment, the compound M1 is also preferably a compound represented by a formula (11) below.
In the formula (11):
a ring A, ring D, and ring E are each independently a cyclic structure selected from the group consisting of a substituted or unsubstituted aryl ring having 6 to 30 ring carbon atoms and a substituted or unsubstituted heterocycle having 5 to 30 ring atoms;
Za is a nitrogen atom or a carbon atom;
Zb is an oxygen atom, a sulfur atom, NRb, C(Rb1)(Rb2), or Si(Rb3)(Rb4);
Zc is a nitrogen atom or a carbon atom;
Zd is a nitrogen atom or a carbon atom;
Ze is a nitrogen atom or a carbon atom;
Zf is a nitrogen atom or a carbon atom;
Zg is an oxygen atom, a sulfur atom, NRg, C(Rg1)(Rg2), or Si(Rg3)(Rg4);
Zh is a nitrogen atom or a carbon atom;
Zi is a nitrogen atom or a carbon atom;
Y is a boron atom, a phosphorus atom, SiRh, P═O or P═S;
Rb, Rb1, Rb2, Rb3, Rb4, Rg, Rg1, Rg2, Rg3, Rg4, and Rh each independently represent the same as Rb, Rb1, Rb2, Rb3, Rb4, Rg, Rg1, Rg2, Rg3, Rg4, and Rh in the formula (1).
In the exemplary embodiment, the compound M1 is also preferably a compound represented by a formula (16) below.
In the formula (16):
at least one combination of adjacent two or more of R161 to R177 are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded; and
R161 to R177 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 50 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 ring carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 50 carbon atoms, a group represented by —Si(R961)(R962)(R963), a group represented by —O—(R964), a group represented by —S—(R965), a group represented by —N(R966)(R967), a group represented by —C(═O)R968, a group represented by —COOR969, a halogen atom, a cyano group, a nitro group, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms; and
R961 to R969 are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms;
when a plurality of R961 are present, the plurality of R961 are mutually the same or different;
when a plurality of R962 are present, the plurality of R962 are mutually the same or different;
when a plurality of R963 are present, the plurality of R963 are mutually the same or different;
when a plurality of R964 are present, the plurality of R964 are mutually the same or different;
when a plurality of R965 are present, the plurality of R965 are mutually the same or different;
when a plurality of R966 are present, the plurality of R966 are mutually the same or different;
when a plurality of R967 are present, the plurality of R967 are mutually the same or different;
when a plurality of R968 are present, the plurality of R968 are mutually the same or different; and
when a plurality of R969 are present, the plurality of R969 are mutually the same or different.
When the compound M1 is a fluorescent compound, the compound M1 preferably emits light having a maximum peak wavelength in a range from 400 nm to 700 nm.
Herein, the maximum peak wavelength means a peak wavelength of a fluorescence spectrum exhibiting a maximum luminous intensity among fluorescence spectra measured in a toluene solution in which a measurement target compound is dissolved at a concentration ranging from 10−6 mol/l to 10−5 mol/l. A spectrophotofluorometer (F-7000 manufactured by Hitachi High-Tech Science Corporation) is used as a measurement device.
The compound M1 preferably exhibits red or green light emission.
Herein, the red light emission refers to light emission whose maximum peak wavelength of fluorescence spectrum is in a range from 600 nm to 660 nm.
When the compound M1 is a red fluorescent compound, the maximum peak wavelength of the compound M1 is preferably in a range from 600 nm to 660 nm, more preferably in a range from 600 nm to 640 nm, further preferably in a range from 610 nm to 630 nm.
Herein, the green light emission refers to light emission whose maximum peak wavelength of fluorescence spectrum is in a range from 500 nm to 560 nm. When the compound M1 is a green fluorescent compound, the maximum peak wavelength of the compound M1 is preferably in a range from 500 nm to 560 nm, more preferably in a range from 500 nm to 540 nm, further preferably in a range from 510 nm to 540 nm.
Herein, the blue light emission refers to light emission whose maximum peak wavelength of fluorescence spectrum is in a range from 430 nm to 480 nm.
When the compound M1 is a blue fluorescent compound, the maximum peak wavelength of the compound M1 is preferably in a range from 430 nm to 480 nm, more preferably in a range from 440 nm to 480 nm.
In the exemplary embodiment, the emitting layer preferably contains an emitting compound that emits light having a maximum peak wavelength in a range from 600 nm to 660 nm.
The maximum peak wavelength of light emitted from the organic EL device is measured as follows.
Voltage is applied on the organic EL devices such that a current density becomes 10 mA/cm2, where spectral radiance spectrum is measured by a spectroradiometer CS-2000 (manufactured by Konica Minolta, Inc.).
A peak wavelength of an emission spectrum, a luminous intensity of which is the maximum in the obtained spectral radiance spectrum, is measured and defined as the maximum peak wavelength (unit: nm).
The compound M1 can be manufactured by a known method.
Specific examples of the compound M1 are shown below. It should however be noted that the invention is not limited to the specific examples of the compound.
A coordinate bond between a boron atom and a nitrogen atom in a pyrromethene skeleton is shown by various means such as a solid line, a broken line, an arrow, and omission. Herein, the coordinate bond is shown by a solid line or a broken line, or the description of the coordinate bond is omitted.
In the organic EL device of the exemplary embodiment, a singlet energy S1(Mat2) of the compound M2 as a delayed fluorescent compound and a singlet energy S1(Mat1) of the fluorescent compound M1 preferably satisfy a relationship of a numerical formula (Numerical Formula 3) below.
S
1(Mat2)>S1(Mat1) (Numerical Formula 7)
An energy gap T77K(Mat2) at 77K of the compound M2 and an energy gap T77K(Mat1) at 77K of the compound M1 preferably satisfy a relationship of a numerical formula (Numerical Formula 7A) below.
T
77K(Mat2)>T77K(Mat1) (Numerical Formula 7A)
It is preferable that, when the organic EL device of the exemplary embodiment emits light, the fluorescent compound M1 mainly emits light in the emitting layer.
Here, a relationship between a triplet energy and an energy gap at 77K will be described. In the exemplary embodiment, the energy gap at 77K is different from a typical triplet energy in some aspects.
The triplet energy is measured as follows. First, a solution in which a compound (measurement target) is dissolved in an appropriate solvent is encapsulated in a quartz glass tube to prepare a sample. A phosphorescent spectrum (ordinate axis: phosphorescent luminous intensity, abscissa axis: wavelength) of the sample is measured at a low temperature (77K). A tangent is drawn to the rise of the phosphorescent spectrum close to the short-wavelength region. The triplet energy is calculated by a predetermined conversion equation based on a wavelength value at an intersection of the tangent and the abscissa axis.
Here, the thermally activated delayed fluorescent compound among the compounds of the exemplary embodiment is preferably a compound having a small ΔST. When ΔST is small, intersystem crossing and inverse intersystem crossing are likely to occur even at a low temperature (77K), so that the singlet state and the triplet state coexist. As a result, the spectrum to be measured in the same manner as the above includes emission from both the singlet state and the triplet state. Although it is difficult to distinguish the emission from the singlet state from the emission from the triplet state, the value of the triplet energy is basically considered dominant.
Accordingly, in the exemplary embodiment, the triplet energy is measured by the same method as a typical triplet energy T, but a value measured in the following manner is referred to as an energy gap T77K in order to differentiate the measured energy from the typical triplet energy in a strict meaning. The measurement target compound is dissolved in EPA (diethylether:isopentane:ethanol=5:5:2 in volume ratio) at a concentration of 10 μmol/L, and the obtained solution is encapsulated in a quartz cell to provide a measurement sample. A phosphorescent spectrum (ordinate axis: phosphorescent luminous intensity, abscissa axis: wavelength) of the measurement sample is measured at a low temperature (77K). A tangent is drawn to the rise of the phosphorescent spectrum close to the short-wavelength region. An energy amount is calculated by a conversion equation (F1) below based on a wavelength value λedge [nm] at an intersection of the tangent and the abscissa axis and is defined as an energy gap T77K at 77K.
T
77K [eV]=1239.85/λedge Conversion Equation (F1):
The tangent to the rise of the phosphorescence spectrum close to the short-wavelength region is drawn as follows. While moving on a curve of the phosphorescence spectrum from the short-wavelength region to the local maximum value closest to the short-wavelength region among the local maximum values of the phosphorescence spectrum, a tangent is checked at each point on the curve toward the long-wavelength of the phosphorescence spectrum. An inclination of the tangent is increased along the rise of the curve (i.e., a value of the ordinate axis is increased).
A tangent drawn at a point of the local maximum inclination (i.e., a tangent at an inflection point) is defined as the tangent to the rise of the phosphorescence spectrum close to the short-wavelength region.
A local maximum point where a peak intensity is 15% or less of the maximum peak intensity of the spectrum is not counted as the above-mentioned local maximum peak intensity closest to the short-wavelength region. The tangent drawn at a point that is closest to the local maximum peak intensity closest to the short-wavelength region and where the inclination of the curve is the local maximum is defined as a tangent to the rise of the phosphorescence spectrum close to the short-wavelength region.
For phosphorescence measurement, a spectrophotofluorometer body F-4500 (manufactured by Hitachi High-Technologies Corporation) is usable. Any device for phosphorescence measurement is usable. A combination of a cooling unit, a low temperature container, an excitation light source and a light-receiving unit may be used for phosphorescence measurement.
A method of measuring the singlet energy S1 with use of a solution (occasionally referred to as a solution method) is exemplified by a method below.
A toluene solution in which a measurement target compound is dissolved at a concentration of 10 μmol/L is prepared and is encapsulated in a quartz cell to provide a measurement sample. Absorption spectrum (ordinate axis: absorption intensity, abscissa axis: wavelength) of the sample is measured at normal temperature (300K). A tangent was drawn to the fall of the absorption spectrum close to the long-wavelength region, and a wavelength value λedge (nm) at an intersection of the tangent and the abscissa axis was assigned to a conversion equation (F2) below to calculate the singlet energy.
S
1 [eV]=1239.85/Δedge Conversion Equation (F2):
Any device for measuring absorption spectrum is usable. For instance, a spectrophotometer (U3310 manufactured by Hitachi, Ltd.) is usable.
The tangent to the fall of the absorption spectrum close to the long-wavelength region is drawn as follows. While moving on a curve of the absorption spectrum from the local maximum value closest to the long-wavelength region, among the local maximum values of the absorption spectrum, in a long-wavelength direction, a tangent at each point on the curve is checked. An inclination of the tangent is decreased and increased in a repeated manner as the curve falls (i.e., a value of the ordinate axis is decreased). A tangent drawn at a point where the inclination of the curve is the local minimum closest to the long-wavelength region (except when absorbance is 0.1 or less) is defined as the tangent to the fall of the absorption spectrum close to the long-wavelength region.
The local maximum absorbance of 0.2 or less is not counted as the above-mentioned local maximum absorbance closest to the long-wavelength region.
In the exemplary embodiment, a difference (S1−T77K) between the singlet energy S1 and the energy gap T77K at 77K is defined as ΔST.
In the exemplary embodiment, a difference ΔST(Mat2) between the singlet energy S1 (Mat2) of the compound M2 and the energy gap T77K(Mat2) at 77K of the compound M2 is preferably less than 0.3 eV, more preferably less than 0.2 eV, further preferably less than 0.1 eV, and still further preferably less than 0.01 eV. That is, ΔST(Mat2) preferably satisfies a relationship of one of numerical formulae (Numerical Formula 1A) to (Numerical Formula 1D) below.
ΔST(Mat2)=S1(Mat2)−T77K(Mat2)<0.3 eV (Numerical Formula 1A)
ΔST(Mat2)=S1(Mat2)−T77K(Mat2)<0.2 eV (Numerical Formula 1B)
ΔST(Mat2)=S1(Mat2)−T77K(Mat2)<0.1 eV (Numerical Formula 1C)
ΔST(Mat2)=S1(Mat2)−T77K(Mat2)<0.01 eV (Numerical Formula 1D)
The organic EL device of the exemplary embodiment preferably emits red light or green light.
When the organic EL device according to the exemplary embodiment emits green light, the maximum peak wavelength of the light emitted from the organic EL device is preferably in a range from 500 nm to 560 nm.
When the organic EL device according to the exemplary embodiment emits red light, the maximum peak wavelength of the light emitted from the organic EL device is preferably in a range from 600 nm to 660 nm.
When the organic EL device according to the exemplary embodiment emits blue light, the maximum peak wavelength of the light emitted from the organic EL device is preferably in a range from 430 nm to 480 nm.
The maximum peak wavelength of the light emitted from the organic EL device is measured as follows.
Voltage is applied on the organic EL devices such that a current density becomes 10 mA/cm2, where spectral radiance spectrum is measured by a spectroradiometer CS-2000 (manufactured by Konica Minolta, Inc.).
A peak wavelength of an emission spectrum, a luminous intensity of which is the maximum in the obtained spectral radiance spectrum, is measured and defined as the maximum peak wavelength (unit: nm).
The film thickness of the emitting layer of the organic EL device in the exemplary embodiment is preferably in a range from 5 nm to 50 nm, more preferably in a range from 7 nm to 50 nm, and most preferably in a range from 10 nm to 50 nm. When the film thickness of the emitting layer is 5 nm or more, the formation of the emitting layer and the adjustment of the chromaticity are easy. When the film thickness of the emitting layer is 50 nm or less, an increase in the drive voltage is likely to be reducible.
For instance, content ratios of the compound M2 and the compound M1 in the emitting layer preferably fall within ranges shown below.
The content ratio of the compound M2 is preferably in a range from 10 mass % to 80 mass %, more preferably in a range from 10 mass % to 60 mass %, and further preferably in a range from 20 mass % to 60 mass %.
The content ratio of the compound M1 is preferably in a range from 0.01 mass % to 10 mass %, more preferably in a range from 0.01 mass % to 5 mass %, and further preferably in a range from 0.01 mass % to 1 mass %.
It should be noted that the emitting layer according to the exemplary embodiment may contain a material other than the compound M2 and the compound M1.
The emitting layer may contain a single type of the compound M2 or may contain two or more types of the compound M2. The emitting layer may contain a single type of the compound M1 or may contain two or more types of the compound M1.
A dashed arrow directed from S1(Mat2) to S1(Mat1) in
As shown in
According to the first exemplary embodiment, an organic EL device that can achieve higher performance (especially, a decrease in voltage), specifically, both luminous efficiency and voltage suitable for practical use, can be provided.
The organic EL device according to the first exemplary embodiment is applicable to an organic electroluminescence display device (hereinafter, occasionally referred to as organic EL display device).
The organic EL device according to the first exemplary embodiment is applicable to an electronic device such as a display device and a light-emitting unit.
An arrangement of the organic EL device 1 is further described below. It should be noted that the reference numerals are occasionally omitted below.
The substrate is used as a support for the organic EL device. For instance, glass, quartz, plastics and the like are usable for the substrate. A flexible substrate is also usable. The flexible substrate is a bendable substrate, which is exemplified by a plastic substrate. Examples of the material for the plastic substrate include polycarbonate, polyarylate, polyethersulfone, polypropylene, polyester, polyvinyl fluoride, polyvinyl chloride, polyimide, and polyethylene naphthalate. Moreover, an inorganic vapor deposition film is also usable.
Metal, an alloy, an electrically conductive compound, a mixture thereof, or the like having a large work function (specifically, 4.0 eV or more) is preferably used as the anode formed on the substrate. Specific examples of the material include ITO (Indium Tin Oxide), indium oxide-tin oxide containing silicon or silicon oxide, indium oxide-zinc oxide, indium oxide containing tungsten oxide and zinc oxide, and graphene. In addition, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chrome (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), titanium (Ti), and nitrides of a metal material (e.g., titanium nitride) are usable.
The material is typically formed into a film by a sputtering method. For instance, the indium oxide-zinc oxide can be formed into a film by the sputtering method using a target in which zinc oxide in a range from 1 mass % to 10 mass % is added to indium oxide. Moreover, for instance, the indium oxide containing tungsten oxide and zinc oxide can be formed by the sputtering method using a target in which tungsten oxide in a range from 0.5 mass % to 5 mass % and zinc oxide in a range from 0.1 mass % to 1 mass % are added to indium oxide. In addition, the anode may be formed by a vacuum deposition method, a coating method, an inkjet method, a spin coating method or the like.
Among the organic layers formed on the anode, since the hole injecting layer adjacent to the anode is formed of a composite material into which holes are easily injectable irrespective of the work function of the anode, a material usable as an electrode material (e.g., metal, an alloy, an electroconductive compound, a mixture thereof, and the elements belonging to the group 1 or 2 of the periodic table) is also usable for the anode.
The elements belonging to the group 1 or 2 of the periodic table, which are a material having a small work function, specifically, an alkali metal such as lithium (Li) and cesium (Cs), an alkaline earth metal such as magnesium (Mg), calcium (Ca) and strontium (Sr), an alloy containing the alkali metal and the alkaline earth metal (e.g., MgAg, AlLi), a rare earth metal such as europium (Eu) and ytterbium (Yb), and an alloy containing the rare earth metal are usable for the anode. It should be noted that the vacuum deposition method and the sputtering method are usable for forming the anode using the alkali metal, alkaline earth metal and the alloy thereof. Further, when a silver paste is used for the anode, the coating method and the inkjet method are usable.
It is preferable to use metal, an alloy, an electroconductive compound, a mixture thereof, or the like having a small work function (specifically, 3.8 eV or less) for the cathode. Examples of materials for the cathode include elements belonging to the group 1 or 2 of the periodic table, specifically, an alkali metal such as lithium (Li) and cesium (Cs), an alkaline earth metal such as magnesium (Mg), calcium (Ca) and strontium (Sr), an alloy containing the alkali metal and the alkaline earth metal (e.g., MgAg, AlLi), a rare earth metal such as europium (Eu) and ytterbium (Yb), and an alloy containing the rare earth metal.
It should be noted that the vacuum deposition method and the sputtering method are usable for forming the cathode using the alkali metal, alkaline earth metal and the alloy thereof. Further, when a silver paste is used for the cathode, the coating method and the inkjet method are usable.
By providing the electron injecting layer, various conductive materials such as Al, Ag, ITO, graphene, and indium oxide-tin oxide containing silicon or silicon oxide may be used for forming the cathode regardless of the work function. The conductive materials can be formed into a film using the sputtering method, inkjet method, spin coating method and the like.
The hole injecting layer is a layer containing a substance exhibiting a high hole injectability. Examples of the substance exhibiting a high hole injectability include molybdenum oxide, titanium oxide, vanadium oxide, rhenium oxide, ruthenium oxide, chrome oxide, zirconium oxide, hafnium oxide, tantalum oxide, silver oxide, tungsten oxide, and manganese oxide.
In addition, the examples of the highly hole-injectable substance include: an aromatic amine compound, which is a low-molecule organic compound, such that 4,4′,4″-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), 4,4′-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl(abbreviation: DPAB), 4,4′-bis(N-{4-[N′-(3-methylphenyl)-N′-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), 3-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), and 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1); and dipyrazino[2,34:20,30-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN).
In addition, a high polymer compound (e.g., oligomer, dendrimer and polymer) is usable as the substance exhibiting a high hole injectability. Examples of the high-molecule compound include poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N′-[4-(4-diphenylamino)phenyl]phenyl-N′-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), and poly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)benzidine] (abbreviation: Poly-TPD). Moreover, an acid-added high polymer compound such as poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonic acid) (PEDOT/PSS) and polyaniline/poly(styrene sulfonic acid) (PAni/PSS) are also usable.
The hole transporting layer is a layer containing a highly hole-transporting substance. An aromatic amine compound, carbazole derivative, anthracene derivative and the like are usable for the hole transporting layer. Specific examples of a material for the hole transporting layer include 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1′-biphenyl]-4,4′-diamine (abbreviation: TPD), 4-phenyl-4′-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: BAFLP), 4,4′-bis[N-(9,9-dimethylfluorene-2-yl)-N-phenylamino]biphenyl (abbreviation: DFLDPBi), 4,4′,4″-tris(N, N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), and 4,4′-bis[N-(spiro-9,9′-bifluorene-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB). The above-described substances mostly have a hole mobility of 10−6 cm2/(V·s) or more.
For the hole transporting layer, a carbazole derivative such as CBP, 9-[4-(N-carbazolyl)]phenyl-10-phenylanthracene (CzPA), and 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (PCzPA) and an anthracene derivative such as t-BuDNA, DNA, and DPAnth may be used. A high polymer compound such as poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyltriphenylamine) (abbreviation: PVTPA) is also usable.
However, in addition to the above substances, any substance exhibiting a higher hole transportability than an electron transportability may be used. It should be noted that the layer containing the substance exhibiting a high hole transportability may be not only a single layer but also a laminate of two or more layers formed of the above substance(s).
When the hole transporting layer includes two or more layers, one of the layers with a larger energy gap is preferably provided closer to the emitting layer.
The electron transporting layer is a layer containing a highly electron-transporting substance. For the electron transporting layer, 1) a metal complex such as an aluminum complex, beryllium complex, and zinc complex, 2) a hetero aromatic compound such as imidazole derivative, benzimidazole derivative, azine derivative, carbazole derivative, and phenanthroline derivative, and 3) a high polymer compound are usable. Specifically, as a low-molecule organic compound, a metal complex such as Alq, tris(4-methyl-8-quinolinato)aluminum (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinolinato)beryllium (abbreviation: BeBq2), BAlq, Znq, ZnPBO and ZnBTZ is usable. In addition to the metal complex, a heteroaromatic compound such as 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(ptert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviation: OXD-7), 3-(4-tert-butylphenyl)-4-phenyl-5-(4-biphenylyl)-1,2,4-triazole (abbreviation: TAZ), 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole (abbreviation: p-EtTAZ), bathophenanthroline (abbreviation: BPhen), bathocuproine (abbreviation: BCP), and 4,4′-bis(5-methylbenzoxazole-2-yl)stilbene (abbreviation: BzOs) is usable. In the present exemplary embodiment, a benzimidazole compound is preferably usable. The above-described substances mostly have an electron mobility of 10−6 cm2/(V·s) or more. It should be noted that any substance other than the above substance may be used for the electron transporting layer as long as the substance exhibits a higher electron transportability than the hole transportability. The electron transporting layer may be provided in the form of a single layer or a laminate of two or more layers of the above substance(s).
Further, a high polymer compound is usable for the electron transporting layer. For instance, poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF-Py), poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2′-bipyridine-6,6′-diyl)] (abbreviation: PF-BPy) and the like are usable.
The electron injecting layer is a layer containing a highly electron-injectable substance. Examples of a material for the electron injecting layer include an alkali metal, alkaline earth metal and a compound thereof, examples of which include lithium (Li), cesium (Cs), calcium (Ca), lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), and lithium oxide (LiOx). In addition, the alkali metal, alkaline earth metal or the compound thereof may be added to the substance exhibiting the electron transportability in use. Specifically, for instance, magnesium (Mg) added to Alq may be used. In this case, the electrons can be more efficiently injected from the cathode.
Alternatively, the electron injecting layer may be provided by a composite material in a form of a mixture of the organic compound and the electron donor. Such a composite material exhibits excellent electron injectability and electron transportability since electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material excellent in transporting the generated electrons. Specifically, the above examples (e.g., the metal complex and the hetero aromatic compound) of the substance forming the electron transporting layer are usable. As the electron donor, any substance exhibiting electron donating property to the organic compound is usable. Specifically, the electron donor is preferably alkali metal, alkaline earth metal and rare earth metal such as lithium, cesium, magnesium, calcium, erbium and ytterbium. The electron donor is also preferably alkali metal oxide and alkaline earth metal oxide such as lithium oxide, calcium oxide, and barium oxide. Moreover, a Lewis base such as magnesium oxide is usable. Further, the organic compound such as tetrathiafulvalene (abbreviation: TTF) is usable.
The organic EL device 1 of the exemplary embodiment includes, between the anode 3 and the emitting layer 5, a hole transporting zone including at least one organic layer. The hole transporting zone shown in
A method for forming each layer of the organic EL device in the present exemplary embodiment is subject to no limitation except for the above particular description. However, known methods of dry film-forming such as vacuum deposition, sputtering, plasma or ion plating and wet film-forming such as spin coating, dipping, flow coating or ink-jet are applicable.
A thickness of each of the organic layers in the organic EL device according to the exemplary embodiment is not limited except for the above particular description. In general, the thickness preferably ranges from several nanometers to 1 μm because excessively small film thickness is likely to cause defects (e.g. pin holes) and excessively large thickness leads to the necessity of applying high voltage and consequent reduction in efficiency.
An arrangement of an organic EL device according to a second exemplary embodiment of the invention is described below. In the description of the second exemplary embodiment, the same components as those in the first exemplary embodiment are denoted by the same reference signs and names to simplify or omit an explanation of the components. In the second exemplary embodiment, the same materials and compounds as described in the first exemplary embodiment are usable, unless otherwise specified.
The organic EL device according to the second exemplary embodiment is different from the organic EL device according to an exemplary arrangement of the first exemplary embodiment in that the emitting layer contains a compound M3 in addition to the delayed fluorescent compound M2 and the fluorescent compound M1. Other components are the same as those in the first exemplary embodiment.
Specifically, in the organic EL device of the second exemplary embodiment, the emitting layer contains the delayed fluorescent compound M2, the fluorescent compound M1, and the compound M3; the first layer contains the first compound satisfying specific parameters (Numerical Formula 1 and Numerical Formula 2); the second layer contains the second compound satisfying a specific parameter (Numerical Formula 3); and the first layer has a film thickness of 15 nm or more.
In the second exemplary embodiment, the compound M2 in the emitting layer is preferably a host material, the compound M1 is preferably a dopant material, and the compound M3 is preferably a host material. One of the compound M2 and the compound M3 is occasionally referred to as a first host material, and the other is occasionally referred to as a second host material.
As the compound M2, the compound M2 described in the first exemplary embodiment is usable.
As the compound M1, the compound M1 described in the first exemplary embodiment is usable.
As the first compound, the first compound described in the first exemplary embodiment is usable.
As the second compound, the second compound described in the first exemplary embodiment is usable.
The compound M3 may be a thermally activated delayed fluorescent compound or a compound exhibiting no thermally activated delayed fluorescence. However, the compound M3 is preferably a compound exhibiting no thermally activated delayed fluorescence.
In the exemplary embodiment, the compound M3 is preferably a compound represented by a formula (3X) or (3Y) below.
In the formula (3X):
A3 is a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms;
L3 is a single bond, a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms, a substituted or unsubstituted divalent heterocyclic group having 5 to 50 ring atoms, a divalent group formed by bonding two groups selected from the group consisting of a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms and a substituted or unsubstituted divalent heterocyclic group having 5 to 50 ring atoms, or a divalent group formed by bonding three groups selected from the group consisting of a substituted or unsubstituted arylene group having 6 to 30 ring carbon atoms and a substituted or unsubstituted divalent heterocyclic group having 5 to 30 ring atoms;
at least one combination of adjacent two or more of R31 to R38 are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded; and
R31 to R38 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted haloalkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 50 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 ring carbon atoms, a group represented by —Si(R901)(R902)(R903), a group represented by —O—(R904), a group represented by —S—(R905), a group represented by —N(R906)(R907), a substituted or unsubstituted aralkyl group having 7 to 50 carbon atoms, a group represented by —C(═O)R908, a group represented by —COOR909, a halogen atom, a cyano group, a nitro group, a group represented by —P(═O)(R931)(R932), a group represented by —Ge(R933)(R934)(R935), a group represented by —B(R936)(R937), a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms, or a group represented by a formula (3A).
In the formula (3A):
RB is a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted haloalkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 50 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 ring carbon atoms, a group represented by —Si(R901)(R902)(R903), a group represented by —O—(R904), a group represented by —S—(R905), a group represented by —N(R906)(R907), a substituted or unsubstituted aralkyl group having 7 to 50 carbon atoms, a group represented by —C(═O)R908, a group represented by —COOR909, a halogen atom, a cyano group, a nitro group, a group represented by —P(═O)(R931)(R932), a group represented by —Ge(R933)(R934)(R935), a group represented by —B(R936)(R937), a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms;
when a plurality of RB are present, the plurality of RB are mutually the same or different;
L31 is: a single bond; a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms, or a trivalent, tetravalent, pentavalent, or hexavalent group derived from the arylene group; a substituted or unsubstituted divalent heterocyclic group having 5 to 50 ring atoms, or a trivalent, tetravalent, pentavalent, or hexavalent group derived from the heterocyclic group; or a divalent group formed by bonding two groups selected from the group consisting of a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms and a substituted or unsubstituted divalent heterocyclic group having 5 to 50 ring atoms, or a trivalent, tetravalent, pentavalent, or hexavalent group derived from the divalent group;
L32 is a single bond, a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms, a substituted or unsubstituted divalent heterocyclic group having 5 to 50 ring atoms;
n3 is 1, 2, 3, 4, or 5;
when L31 is a single bond, n3 is 1 and L32 is bonded to a carbon atom in a six-membered ring in the formula (3X);
when a plurality of L32 are present, the plurality of L32 are mutually the same or different; and
* represents a bonding position to a carbon atom in a six-membered ring in the formula (3X).
In the compound M3:
R901, R902, R903, R904, R905, R906, R907, R908, R909, R931, R932, R933, R934, R935, R936, and R937 are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 ring carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms;
when a plurality of R901 are present, the plurality of R901 are mutually the same or different;
when a plurality of R902 are present, the plurality of R902 are mutually the same or different;
when a plurality of R903 are present, the plurality of R903 are mutually the same or different;
when a plurality of R904 are present, the plurality of R904 are mutually the same or different;
when a plurality of R905 are present, the plurality of R905 are mutually the same or different;
when a plurality of R906 are present, the plurality of R906 are mutually the same or different;
when a plurality of R907 are present, the plurality of R907 are mutually the same or different;
when a plurality of R908 are present, the plurality of R908 are mutually the same or different;
when a plurality of R909 are present, the plurality of R909 are mutually the same or different;
when a plurality of R931 are present, the plurality of R931 are mutually the same or different;
when a plurality of R932 are present, the plurality of R932 are mutually the same or different;
when a plurality of R933 are present, the plurality of R933 are mutually the same or different;
when a plurality of R934 are present, the plurality of R934 are mutually the same or different;
when a plurality of R935 are present, the plurality of R935 are mutually the same or different;
when a plurality of R936 are present, the plurality of R936 are mutually the same or different; and
when a plurality of R937 are present, the plurality of R937 are mutually the same or different.
The compound M3 is also preferably a compound represented by any of formulae (31) to (36) below.
In the formulae (31) to (36):
A3 and L3 respectively represent the same as A3 and L3 in the formula (3X);
at least one combination of adjacent two or more of R341 to R350 are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded;
X31 is a sulfur atom, an oxygen atom, NR352, or CR353R354;
a combination of R353 and R354 are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded; and
R341 to R350 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring, R352, and R353 and R354 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring each independently represent the same as R31 to R38 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring.
In the compound M3, it is preferable that R352 is a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms.
In the compound M3, it is preferable that a combination of R353 and R354 are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded; and R353 and R354 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring are each independently a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms.
In the compound M3, X31 is preferably is a sulfur atom or an oxygen atom.
In the compound M3, A3 is preferably a group represented by any of formulae (A31) to (A37) below.
In the formulae (A31) to (A37):
at least one combination of adjacent two or more of a plurality of R300 are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded;
R300 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring, and R333 each independently represent the same as R31 to R38 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring; and
* in each of the formulae (A31) to (A37) represents a bonding position to L3 of the compound M3.
In the compound M3, A3 is also preferably a group represented by the formula (A34), (A35), or (A37).
The compound M3 is also preferably a compound represented by any of formulae (311) to (316) below.
In the formulae (311) to (316):
L3 represents the same as L3 in the formula (3X);
at least one combination of adjacent two or more of a plurality of R300 are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded;
at least one combination of adjacent two or more of R341 to R350 are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded; and
R300 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring, and R341 to R350 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring each independently represent the same as R31 to R38 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring.
The compound M3 is also preferably a compound represented by a formula (321) below.
In the formula (321):
L3 represents the same as L3 in the formula (3X); and
R31 to R38, and R301 to R308 each independently represent the same as R31 to R38 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring.
In the compound M3, L3 is preferably a single bond, or a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms.
In the compound M3, L3 is preferably a single bond, a substituted or unsubstituted phenylene group, a substituted or unsubstituted biphenylene group, or a substituted or unsubstituted terphenylene group.
In the compound M3, L3 is preferably a group represented by a formula (317) below.
In the formula (317), each R310 independently represents the same as R31 to R38 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring, and each * independently represents a bonding position.
In the compound M3, L3 also preferably contains a divalent group represented by a formula (318) or (319) below.
In the compound M3, L3 is also preferably a divalent group represented by the formula (318) or (319).
The compound M3 is also preferably a compound represented by a formula (322) or (323) below.
In the formulae (322) and (323):
L31 is: a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms; a substituted or unsubstituted divalent heterocyclic group having 5 to 50 ring atoms; or a divalent group formed by bonding two groups selected from the group consisting of a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms and a substituted or unsubstituted divalent heterocyclic group having 5 to 50 ring atoms;
L31 contains a divalent group represented by the formula (318) or (319); and
R31 to R38, R300, and R321 to R328 each independently represent the same as R31 to R38 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring.
In the formula (319), a combination of adjacent two of a plurality of R304 are mutually bonded to form a ring represented by the formula (320).
In the formula (320), 1* and 2* each independently represent a bonding position to a ring bonded to R304.
R302 in the formula (318), R303 in the formula (318), R303 in the formula (319), R304 not forming the ring represented by the formula (320), and R305 in the formula (320) each independently represent the same as R31 to R38 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring.
* in each of the formulae (318) to (320) represents a bonding position.
In the compound M3, the group as L3 or L31 that is represented by the formula (319) is, for instance, a group represented by a formula (319A) below.
In the formula (319A), R303, R304, and R305 each independently represent the same as R31 to R38 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring, and each * in the formula (319A) represents a bonding position.
It is also preferable that the compound M3 is a compound represented by the formula (322) and L31 is a group represented by the formula (318) below.
The compound M3 is also preferably a compound represented by a formula (324) below.
In the formula (324), R31 to R38, R300, and R302 each independently represent the same as R31 to R38 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring.
It is preferable that R31 to R38 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms, or a group represented by the formula (3A); and RB in the formula (3A) is a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms.
It is preferable that R31 to R38 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring are each independently a hydrogen atom, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a group represented by the formula (3A); and RB in the formula (3A) is a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms.
It is preferable that R31 to R38 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring are each independently a hydrogen atom, a substituted or unsubstituted phenyl group, or a group represented by the formula (3A); and RB in the formula (3A) is a substituted or unsubstituted phenyl group.
The compound M3 is also preferably a compound not having a pyridine ring, a pyrimidine ring, and a triazine ring.
In the formula (3Y):
Y31 to Y36 are each independently CR3 or a nitrogen atom;
two or more of Y31 to Y36 are each a nitrogen atom;
when a plurality of R3 are present, at least one combination of adjacent two or more of the plurality of R3 are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded; and
each R3 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring is independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted haloalkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 50 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 ring carbon atoms, a group represented by —Si(R901)(R902)(R903), a group represented by —O—(R904), a group represented by —S—(R905), a group represented by —N(R906)(R907), a substituted or unsubstituted aralkyl group having 7 to 50 carbon atoms, a group represented by —C(═O)R908, a group represented by —COOR909, a halogen atom, a cyano group, a nitro group, a group represented by —P(═O)(R931)(R932), a group represented by —Ge(R933)(R934)(R935), a group represented by —B(R936)(R937), a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms, or a group represented by a formula (3B) below.
In the formula (3B): RB, L31, L32 and n3 each independently represent the same as RB, L31, L32 and n3 in the formula (3A);
when a plurality of RB are present, the plurality of RB are mutually the same or different;
when L31 is a single bond, n3 is 1 and L32 is bonded to a carbon atom in a six-membered ring in the formula (3Y);
when a plurality of L32 are present, the plurality of L32 are mutually the same or different; and
* represents a bonding position to a carbon atom in a six-membered ring in the formula (3Y).
The compound M3 preferably does not include a pyridine ring in a molecule.
The compound M3 is also preferably a compound represented by a formula (31a) or (32a) below.
In the formula (32a):
at least one combination of adjacent two or more of R35 to R37 are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded; and
R31 to R33 in the formula (31a), R34 in the formula (32a), and R35 to R37 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring each independently represent the same as R3 in the formula (3Y).
The compound M3 is also preferably a compound represented by the formula (31a).
It is preferable that each R3 in the formula (3Y) is independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms, or a group represented by the formula (3B).
It is preferable that each R3 in the formula (3Y) is independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a group represented by the formula (3B).
The compound M3 represented by the formula (3Y) preferably contains, in a molecule, at least one group selected from the group consisting of groups represented by formulae (B31) to (B44) below.
In the formulae (B31) to (B38):
at least one combination of adjacent two or more of a plurality of R300 are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded;
a combination of R331 and R332 are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded;
R300, R331 and R332 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring, and R333 are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted haloalkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 50 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 ring carbon atoms, a group represented by —Si(R901)(R902)(R903), a group represented by —O—(R904), a group represented by —S—(R905), a group represented by —N(R906)(R907), a substituted or unsubstituted aralkyl group having 7 to 50 carbon atoms, a group represented by —C(═O)R908, a group represented by —COOR909, a halogen atom, a cyano group, a nitro group, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms; and
* in each of the formulae (B31) to (B38) represents a bonding position to any other atom in a molecule of the compound M3.
In the formulae (B39) to (B44):
at least one combination of adjacent two or more of R341 to R350 are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded;
at least one of R341 to R351 represents a bonding position to any other atom in a molecule of the compound M3;
X31 is a sulfur atom, an oxygen atom, NR352, or CR353R354;
R341 to R351 not being the bonding position to any other atom in the molecule of the compound M3, not forming the substituted or unsubstituted monocyclic ring, and not forming the substituted or unsubstituted fused ring; R352; and R353 and R354 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted haloalkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 50 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 ring carbon atoms, a group represented by —Si(R901)(R902)(R903), a group represented by —O—(R904), a group represented by —S—(R905), a group represented by —N(R906)(R907), a substituted or unsubstituted aralkyl group having 7 to 50 carbon atoms, a group represented by —C(═O)R908, a group represented by —COOR909, a halogen atom, a cyano group, a nitro group, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms.
The compound M3 represented by the formula (3Y) preferably contains, in a molecule, at least one group selected from the group consisting of groups represented by the formulae (B38) to (B44).
In the formula (3Y), it is preferable that at least one of Y31 to Y36 is CR3, at least one R3 is a group represented by the formula (3B), and RB is a group represented by any of the formulae (B31) to (B44).
In the formula (3Y), it is preferable that at least one of Y31 to Y36 is CR3, at least one R3 is a group represented by the formula (3B), and RB is a group represented by any of the formulae (B38) to (B44).
In the formulae (3A) and (3B), it is preferable that:
L31 is: a single bond; a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms, or a trivalent, tetravalent, pentavalent, or hexavalent group derived from the arylene group; or a divalent group formed by bonding two groups selected from the group consisting of a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms, or a trivalent, tetravalent, pentavalent, or hexavalent group derived from the divalent group; and
each L32 is independently a single bond, or a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms.
In the formulae (3A) and (3B), it is preferable that:
L31 is a single bond, or a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms;
n3 is 1; and
L32 is a single bond, or a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms.
In the formulae (3A) and (3B), it is preferable that:
L31 is: a single bond; a substituted or unsubstituted phenylene group; a substituted or unsubstituted biphenylene group; or a divalent group formed by bonding two groups selected from the group consisting of a substituted or unsubstituted phenylene group and a substituted or unsubstituted biphenylene group, or a trivalent, tetravalent, pentavalent, or hexavalent group derived from the divalent group;
n3 is 1; and
L32 is a single bond, a substituted or unsubstituted phenylene group, or a substituted or unsubstituted biphenylene group.
In the compounds represented by the formulae (3X) and (3Y), R352 is preferably a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms.
In the compounds represented by the formulae (3X) and (3Y), it is preferable that:
a combination of R353 and R354 are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded; and
R353 and R354 forming neither the substituted or unsubstituted monocyclic ring nor the substituted or unsubstituted fused ring are each independently a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms.
In the compounds represented by the formulae (3X) and (3Y), it is preferable that:
the substituent for the “substituted or unsubstituted” group is an unsubstituted alkyl group having 1 to 25 carbon atoms, an unsubstituted alkenyl group having 2 to 25 carbon atoms, an unsubstituted alkynyl group having 2 to 25 carbon atoms, an unsubstituted cycloalkyl group having 3 to 25 ring carbon atoms, a group represented by —Si(R901)(R902)(R903), a group represented by —O—(R904), a group represented by —S—(R905), a group represented by —N(R906)(R907), an unsubstituted aralkyl group having 7 to 50 carbon atoms, a group represented by —C(═O)R908, a group represented by —COOR909, a group represented by —P(═O)(R931)(R932), a group represented by —Ge(R933)(R934)(R935), a group represented by —B(R936)(R937), a group represented by —S(═O)2R938, a halogen atom, a cyano group, a nitro group, an unsubstituted aryl group having 6 to 25 ring carbon atoms, or an unsubstituted heterocyclic group having 5 to 25 ring atoms; and
R901 to R909 and R931 to R938 are each independently a hydrogen atom, an unsubstituted alkyl group having 1 to 25 carbon atoms, an unsubstituted aryl group having 6 to 25 ring carbon atoms, or an unsubstituted heterocyclic group having 5 to 25 ring atoms.
In the compounds represented by the formulae (3X) and (3Y), it is preferable that the substituent for the “substituted or unsubstituted” group is a halogen atom, an unsubstituted alkyl group having 1 to 25 carbon atoms, an unsubstituted aryl group having 6 to 25 ring carbon atoms, or an unsubstituted heterocyclic group having 5 to 25 ring atoms.
In the compounds represented by the formulae (3X) and (3Y), it is preferable that the substituent for the “substituted or unsubstituted” group is an unsubstituted alkyl group having 1 to 10 carbon atoms, an unsubstituted aryl group having 6 to 12 ring carbon atoms, or an unsubstituted heterocyclic group having 5 to 12 ring atoms.
In the compounds represented by the formulae (3X) and (3Y), it is also preferable that the groups specified to be “substituted or unsubstituted” are each an “unsubstituted” group.
The compound M3 according to the exemplary embodiment can be manufactured by a known method.
Specific examples of the compound M3 of the exemplary embodiment include compounds below. It should however be noted that the invention is not limited to the specific examples of the compound.
Relationship between Compound M1, Compound M2, and Compound M3 in Emitting Layer
In the organic EL device according to the exemplary embodiment, the singlet energy S1 (Mat2) of the compound M2 and a singlet energy S1 (Mat3) of the compound M3 preferably satisfy a relationship of a numerical formula (Numerical Formula 4) below.
S
1(Mat3)>S1(Mat2) (Numerical Formula 4)
An energy gap T77K(Mat3) at 77K of the compound M3 is preferably larger than the energy gap T77K(Mat2) at 77K of the compound M2.
The energy gap T77K(Mat3) at 77K of the compound M3 is preferably larger than the energy gap T77K(Mat1) at 77K of the compound M1.
In the organic EL device according to the exemplary embodiment, the singlet energy S1 (Mat2) of the compound M2, the singlet energy S1 (Mat1) of the compound M1, and the singlet energy S1(Mat3) of the compound M3 preferably satisfy a relationship of a numerical formula (Numerical Formula 5) below.
S
1(Mat3)>S1(Mat2)>S1(Mat1) (Numerical Formula 5)
In the organic EL device according to the exemplary embodiment, the energy gap T77K(Mat2) at 77K of the compound M2, the energy gap T77K(Mat1) at 77K of the compound M1, and the energy gap T77K(Mat3) at 77K of the compound M3 preferably satisfy a relationship of a numerical formula (Numerical Formula 5A) below.
T
77K(Mat3)>T77K(Mat2)>T77K(Mat1) (Numerical Formula 5A)
It is preferable that, when the organic EL device of the exemplary embodiment emits light, the fluorescent compound M1 mainly emits light in the emitting layer.
The organic EL device of the exemplary embodiment preferably emits red light or green light.
The maximum peak wavelength of light emitted from the organic EL device can be measured by the same method as that for the organic EL device of the first exemplary embodiment.
For instance, content ratios of the compound M1, the compound M2, and the compound M3 in the emitting layer preferably fall within ranges shown below.
The content ratio of the compound M1 is preferably in a range from 0.01 mass % to 10 mass %, more preferably in a range from 0.01 mass % to 5 mass %, further preferably in a range from 0.01 mass % to 1 mass %.
The content ratio of the compound M2 is preferably in a range from 10 mass % to 80 mass %, more preferably in a range from 10 mass % to 60 mass %, further preferably in a range from 20 mass % to 60 mass %.
The content ratio of the compound M3 is preferably in a range from 10 mass % to 80 mass %.
The upper limit of the total of the content ratios of the compound M1, the compound M2, and the compound M3 in the emitting layer is 100 mass %. It should be noted that the emitting layer according to the exemplary embodiment may contain a material other than the compound M1, the compound M2, and the compound M3.
The emitting layer may contain a single type of the compound M1 or may contain two or more types of the compound M1. The emitting layer may contain a single type of the compound M2 or may contain two or more types of the compound M2. The emitting layer may contain a single type of the compound M3 or may contain two or more types of the compound M3.
As shown in
According to the second exemplary embodiment, an organic EL device that can achieve higher performance (especially, a decrease in voltage), specifically, both luminous efficiency and voltage suitable for practical use, can be provided.
The organic EL device according to the second exemplary embodiment is applicable to an organic EL display device.
The organic EL device according to the second exemplary embodiment is applicable to an electronic device such as a display device and a light-emitting unit.
An arrangement of an organic EL device according to a third exemplary embodiment of the invention is described below. In the description of the third exemplary embodiment, the same components as those in the first and second exemplary embodiments are denoted by the same reference signs and names to simplify or omit an explanation of the components. In the third exemplary embodiment, any materials and compounds that are not specified may be the same as those in the first and second exemplary embodiments.
The organic EL device according to the third exemplary embodiment is different from the organic EL device according to an exemplary arrangement of the first exemplary embodiment in that the emitting layer contains the delayed fluorescent compound M2 and a compound M4. Other components are the same as those in the first exemplary embodiment.
Specifically, in the organic EL device of the third exemplary embodiment, the emitting layer contains the delayed fluorescent compound M2 and the compound M4; the first layer contains the first compound satisfying specific parameters (Numerical
Formula 1 and Numerical Formula 2); the second layer contains the second compound satisfying a specific parameter (Numerical Formula 3); and the first layer has a film thickness of 15 nm or more.
In the third exemplary embodiment, the compound M2 in the emitting layer is preferably a dopant material, and the compound M4 is preferably a host material.
The compound M4 may be a delayed fluorescent compound or a compound exhibiting no delayed fluorescence.
The compound M4 is not particularly limited, and the compound M3 described in the second exemplary embodiment is usable as the compound M4.
As the compound M2, the compound M2 described in the first exemplary embodiment is usable.
As the first compound, the first compound described in the first exemplary embodiment is usable.
As the second compound, the second compound described in the first exemplary embodiment is usable.
Relationship between Compound M2 and Compound M4 in Emitting Layer In the organic EL device according to the exemplary embodiment, the singlet energy S1 (Mat2) of the compound M2 and a singlet energy S1 (Mat4) of the compound M4 preferably satisfy a relationship of a numerical formula (Numerical Formula 6) below.
S
1(Mat4)>S1(Mat2) (Numerical Formula 6)
An energy gap T77K(Mat4) at 77K of the compound M4 is preferably larger than the energy gap T77K(Mat2) at 77K of the compound M2.
It is preferable that, when the organic EL device of the exemplary embodiment emits light, the compound M2 mainly emits light in the emitting layer.
For instance, content ratios of the compound M2 and the compound M4 in the emitting layer preferably fall within ranges shown below.
The content ratio of the compound M2 is preferably in a range from 10 mass % to 80 mass %, more preferably in a range from 10 mass % to 60 mass %, and further preferably in a range from 20 mass % to 60 mass %.
The content ratio of the compound M4 is preferably in a range from 20 mass % to 90 mass %, more preferably in a range from 40 mass % to 90 mass %, and further preferably in a range from 40 mass % to 80 mass %.
It should be noted that the emitting layer according to the exemplary embodiment may contain a material other than the compound M2 and the compound M4.
The emitting layer may contain a single type of the compound M2 or may contain two or more types of the compound M2. The emitting layer may contain a single type of the fourth compound or may contain two or more types of the fourth compound.
The inverse intersystem crossing caused in the compound M2 enables light emission from the lowest singlet state S1(Mat2) of the compound M2 to be observed when the emitting layer does not contain a fluorescent dopant with the lowest singlet state S1 smaller than the lowest singlet state S1(Mat2) of the compound M2. It is inferred that the internal quantum efficiency can be theoretically raised up to 100% also by using delayed fluorescence by the TADF mechanism.
According to the third exemplary embodiment, an organic EL device that can achieve higher performance (especially, a decrease in voltage), specifically, both luminous efficiency and voltage suitable for practical use, can be provided.
The organic EL device according to the third exemplary embodiment is applicable to an organic EL display device.
The organic EL device according to the third exemplary embodiment is applicable to an electronic device such as a display device and a light-emitting unit.
An organic EL display device of a fourth exemplary embodiment is an organic electroluminescence display device including: an anode and a cathode arranged to face each other; a blue-emitting organic EL device as a blue pixel; a green-emitting organic EL device as a green pixel; and a red-emitting organic EL device as a red pixel, in which:
the red pixel includes the organic EL device according to any of the first to third exemplary embodiments as the red-emitting organic EL device;
the red-emitting organic EL device includes a red emitting layer as the emitting layer, the first layer provided between the red emitting layer and the anode, and the second layer provided between the first layer and the anode;
the blue-emitting organic EL device includes a blue emitting layer provided between the anode and the cathode;
the green-emitting organic EL device includes a green emitting layer provided between the anode and the cathode; and
the second layer is provided between the anode and each of the blue emitting layer, the green emitting layer, and the first layer in a shared manner across the blue-emitting organic EL device, the green-emitting organic EL device, and the red-emitting organic EL device.
In the organic EL display device of the fourth exemplary embodiment, the red-emitting organic EL device included in the red pixel is an organic EL device that emits light using the TADF mechanism, and the red-emitting organic EL device is the organic EL device according to any of the first to third exemplary embodiments.
Specifically, the organic EL display device of the fourth exemplary embodiment includes the red-emitting organic EL device in which the first layer provided between the red emitting layer and the anode contains the first compound satisfying specific parameters (Numerical Formula 1 and Numerical Formula 2); and the second layer provided between the first layer and the anode contains the second compound satisfying a specific parameter (Numerical Formula 3); and the first layer has a film thickness of 15 nm or more. Even when the red-emitting organic EL device includes the first layer with an increased film thickness due to the same reasons as in the first exemplary embodiment, both luminous efficiency and voltage suitable for practical use can be achieved.
Thus, in the organic EL display device of the fourth exemplary embodiment, cavity adjustment can be easily performed, for instance, by simply increasing the film thickness of the first layer of the red-emitting organic EL device.
Since the organic EL display device of the fourth exemplary embodiment includes the red-emitting organic EL device that can achieve higher performance (especially, a decrease in voltage), specifically, both luminous efficiency and voltage suitable for practical use, the organic EL display device of the fourth exemplary embodiment can achieve higher performance.
Herein, “blue”, “green”, or “red” used for each element, such as “pixel”, “emitting layer”, “organic layer”, or “material”, is used to distinguish one from another. Although “blue”, “green”, or “red” may represent a color of light emitted from “pixel”, “emitting layer”, “organic layer”, or “material”, “blue”, “green”, or “red” does not mean the color of appearance of each element.
Referring to
The organic EL display device 100A includes electrodes and organic layers supported by a substrate 2A.
The organic EL display device 100A includes an anode 3 and a cathode 4 arranged to face each other.
The organic EL display device 100A includes a blue-emitting organic EL device 10B as a blue pixel, a green-emitting organic EL device 10G as a green pixel, and a red-emitting organic EL device 10R as a red pixel.
In the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R of the organic EL display device 100A, the anode-side organic layer 63 and the second layer 62 are provided between the anode 3 and each of the blue emitting layer 53, the green emitting layer 54, and the first layer 61.
The anode-side organic layer 63 and the second layer 62 are arranged in a shared manner across the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R.
In the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R of the organic EL display device 100A, the electron transporting layer 8 and the electron injecting layer 9 are provided between the cathode 4 and each of the blue emitting layer 53, the green emitting layer 54, and a red emitting layer 50.
The electron transporting layer 8 and the electron injecting layer 9 are arranged in a shared manner across the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R.
In the red-emitting organic EL device 10R, the first layer 61 as the non-common layer is provided between the red emitting layer 50 and the second layer 62. The red emitting layer 50 corresponds to the emitting layer according to any of the first exemplary embodiment, the second exemplary embodiment, and the third exemplary embodiment. The first layer 61 corresponds to the first layer according to any of the first exemplary embodiment, the second exemplary embodiment, and the third exemplary embodiment. The second layer 62 corresponds to the second layer according to any of the first exemplary embodiment, the second exemplary embodiment, and the third exemplary embodiment. In
In
The anode 3 is independently provided for each of the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R. Thus, the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R can be individually driven in the organic EL display device 100A. The respective anodes of the organic EL devices 10B,10G, and 10R are insulated from each other by an insulation material (not shown). The cathode 4 is provided in a shared manner across the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R.
In an exemplary embodiment, the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R as pixels are arranged in parallel with each other on the substrate 2A.
In the organic EL display device 100A according to the fourth exemplary embodiment, the second layer 62 is preferably in direct contact with each of the blue emitting layer 53, the green emitting layer 54, and the first layer 61.
The invention is not limited to the arrangement of the organic EL display device shown in
For instance, in an exemplary arrangement of the organic EL display device of the exemplary embodiment, the blue-emitting organic EL device, the green-emitting organic EL device, and the red-emitting organic EL device may each independently further include a layer different from the layers shown in
For instance, in an exemplary arrangement of the organic EL display device of the exemplary embodiment, the blue-emitting organic EL device and the green-emitting organic EL device may be each independently a device that fluoresces or a device that phosphoresces. The red-emitting organic EL device is preferably a device that fluoresces.
The blue-emitting organic EL device and the green-emitting organic EL device are explained. The organic EL device according to any of the first to third exemplary embodiments is applicable to the red-emitting organic EL device.
In an exemplary arrangement of the organic EL display device of the exemplary embodiment, the blue emitting layer contains a host material. For instance, the blue emitting layer contains 50 mass % or more of the host material with respect to a total mass of the blue emitting layer.
In an exemplary arrangement of the organic EL display device of the exemplary embodiment, the blue emitting layer of the blue-emitting organic EL device contains a blue emitting compound that emits light having a maximum peak wavelength in a range from 430 nm to 500 nm. The blue emitting compound is, for instance, a fluorescent compound that emits fluorescence having a maximum peak wavelength in a range from 430 nm to 500 nm. Further, the blue emitting compound is, for instance, a phosphorescent compound that exhibits phosphorescence having a maximum peak wavelength in a range from 430 nm to 500 nm. Herein, the blue light emission refers to a light emission in which the maximum peak wavelength of emission spectrum is in a range from 430 nm to 500 nm.
The fluorescent compound is a compound capable of emitting in a singlet state. The phosphorescent compound is a compound capable of emitting in a triplet state.
Examples of a blue fluorescent compound usable for the blue emitting layer include a pyrene derivative, a styrylamine derivative, a chrysene derivative, a fluoranthene derivative, a fluorene derivative, a diamine derivative, and a triarylamine derivative. Specific examples thereof include N,N′-bis[4-(9H-carbazole-9-yl)phenyl]-N,N′-diphenylstilbene-4,4′-diamine (abbreviation: YGA2S), 4-(9H-carbazole-9-yl)-4′-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), and 4-(10-phenyl-9-anthryl)-4′-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBAPA).
Examples of a blue phosphorescent compound usable for the blue emitting layer include metal complexes such as an iridium complex, an osmium complex, and a platinum complex. Specific examples thereof include bis[2-(4′,6′-difluorophenyl)pyridinato-N,C2′]iridium(III)tetrakis(1-pyrazolyl)borate (abbreviation: Flr6), bis[2-(4′,6′-difluorophenyl)pyridinato-N, C2′]iridium(III)picolinate (abbreviation: Flrpic), bis[2-(3′,5′bistrifluoromethylphenyl)pyridinato-N,C2′]iridium(III)picolinate (abbreviation: Ir(CF3ppy)2(pic)), and bis[2-(4′,6′-difluorophenyl)pyridinato-N,C2′]iridium(III)acetylacetonato (abbreviation: Flracac).
A maximum peak wavelength (maximum phosphorescence peak wavelength) of a phosphorescent compound is measurable by the following method.
A measurement target compound is dissolved in EPA (diethylether:isopentane:ethanol=5:5:2 in volume ratio) so as to fall within a range from 10−5 mol/L to 10−4 mol/L, and the obtained EPA solution is encapsulated in a quartz cell to provide a measurement sample. A phosphorescence spectrum (ordinate axis: phosphorescent luminous intensity, abscissa axis: wavelength) of the measurement sample is measured at a low temperature (77K). The local maximum value closest to the short-wavelength region among the local maximum values of the phosphorescence spectrum is defined as the maximum phosphorescence peak wavelength. A spectrophotofluorometer F-7000 manufactured by Hitachi High-Tech Science Corporation can be used to measure phosphorescence. Any device for phosphorescence measurement is usable. A combination of a cooling unit, a low temperature container, an excitation light source and a light-receiving unit may be used for phosphorescence measurement. Herein, the maximum peak wavelength of phosphorescence is occasionally referred to as the maximum phosphorescence peak wavelength (PH-peak).
In an exemplary arrangement of the organic EL display device of the exemplary embodiment, the green emitting layer contains a host material. For instance, the green emitting layer contains 50 mass % or more of the host material with respect to a total mass of the green emitting layer.
In an exemplary arrangement of the organic EL display device of the exemplary embodiment, the green emitting layer of the green-emitting organic EL device contains a green emitting compound that emits light having a maximum peak wavelength in a range from 500 nm to 550 nm. The green emitting compound is, for instance, a fluorescent compound that emits fluorescence having a maximum peak wavelength in a range from 500 nm to 550 nm. Further, the green emitting compound is, for instance, a phosphorescent compound that exhibits phosphorescence having a maximum peak wavelength in a range from 500 nm to 550 nm. Herein, the green light emission refers to a light emission in which a maximum peak wavelength of emission spectrum is in a range from 500 nm to 550 nm.
The fluorescent compound is a compound capable of emitting in a singlet state. The phosphorescent compound is a compound capable of emitting in a triplet state.
Examples of a green fluorescent compound usable for the green emitting layer include an aromatic amine derivative. Examples of a green phosphorescent compound usable for the green emitting layer include an iridium complex.
In an exemplary arrangement of the organic EL display device of the exemplary embodiment, the host material in the blue emitting layer and the host material in the green emitting layer are, for instance, a compound for dispersing a highly emittable substance (dopant material) in the emitting layers. As the host material in the blue emitting layer and the host material in the green emitting layer, it is possible to use, for instance, a substance having a higher Lowest Unoccupied Molecular Orbital (LUMO) level and a lower Highest Occupied Molecular Orbital (HOMO) level than the highly emittable substance.
For instance, the following compounds (1) to (4) are each independently usable as the host material in the blue emitting layer and the host material in the green emitting layer.
(1) a metal complex such as an aluminum complex, a beryllium complex, or a zinc complex
(2) a heterocyclic compound such as an oxadiazole derivative, a benzimidazole derivative, or a phenanthroline derivative
(3) a fused aromatic compound such as a carbazole derivative, an anthracene derivative, a phenanthrene derivative, a pyrene derivative or a chrysene derivative
(4) an aromatic amine compound such as a triarylamine derivative or a fused polycyclic aromatic amine derivative
Referring to
In an exemplary embodiment, the anode 3 is disposed to face the cathode 4.
In an exemplary embodiment, the anode 3 is typically the non-common layer. In an exemplary embodiment, for instance, when the anode 3 is the non-common layer, the respective anodes in the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G and the red-emitting organic EL device 10R are physically separated from each other, and specifically, may be insulated from each other by an insulation material (not shown) or the like.
In an exemplary embodiment, the cathode 4 is disposed to face the anode 3.
In an exemplary embodiment, the cathode 4 may be the common layer or the non-common layer.
In an exemplary embodiment, the cathode 4 is preferably the common layer provided in a shared manner across the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R.
In an exemplary embodiment, the cathode 4 is in direct contact with the electron injecting layer 9.
In an exemplary embodiment, when the cathode 4 is the common layer, the film thickness of the cathode 4 is constant over the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R. When the cathode 4 is the common layer, the cathode 4 provided for the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R can be produced without changing a mask or the like. The organic EL display device 100A thus has enhanced productivity.
In an exemplary embodiment, the electron transporting layer 8 is the common layer provided in a shared manner across the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R.
In an exemplary embodiment, the electron transporting layer 8 is provided between the electron injecting layer 9 and the emitting layers of the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R.
In an exemplary embodiment, the side of the electron transporting layer 8 close to the anode 3 is in direct contact with the blue emitting layer 53, the green emitting layer 54, and the red emitting layer 50.
The side of the electron transporting layer 8 close to the cathode 4 is in direct contact with the electron injecting layer 9.
In an exemplary embodiment, the electron transporting layer 8 is the common layer. In this case, the film thickness of the electron transporting layer 8 is constant over the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R. When the electron transporting layer 8 is the common layer, the electron transporting layer 8 provided for the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R can be produced without changing a mask or the like. The organic EL display device 100A thus has enhanced productivity.
In an exemplary embodiment, the electron injecting layer 9 is the common layer provided in a shared manner across the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R.
In an exemplary embodiment, the electron injecting layer 9 is disposed between the electron transporting layer 8 and the cathode 4.
In an exemplary embodiment, the electron injecting layer 9 is in direct contact with the electron transporting layer 8.
In an exemplary embodiment, the electron injecting layer 9 is the common layer. In this case, the film thickness of the electron injecting layer 9 is constant over the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R. When the electron injecting layer 9 is the common layer, the electron injecting layer 9 provided for the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R can be produced without changing a mask or the like. The organic EL display device 100A thus has enhanced productivity.
An arrangement of an organic EL display device according to a fifth exemplary embodiment of the invention is described below. In the description of the fifth exemplary embodiment, the same components as those in the first to fourth exemplary embodiments are denoted by the same reference signs and names to simplify or omit an explanation of the components. In the fifth exemplary embodiment, any materials and compounds that are not specified may be the same as those in the first to fourth exemplary embodiments.
The organic EL display device according to the fifth exemplary embodiment is different from the organic EL display device according to the fourth exemplary embodiment in that the blue-emitting organic EL device includes a blue organic layer provided between the blue emitting layer and the anode and the green-emitting organic EL device includes a green organic layer provided between the green emitting layer and the anode. Other components are the same as those in the organic EL display device of the fourth exemplary embodiment.
In the organic EL display device of the fifth exemplary embodiment, similar to the fourth exemplary embodiment, the red-emitting organic EL device included in the red pixel is an organic EL device that emits light using the TADF mechanism, and the red-emitting organic EL device is the organic EL device according to any of the first to third exemplary embodiments. Even when the red-emitting organic EL device includes the first layer with an increased film thickness, both luminous efficiency and voltage suitable for practical use can be achieved.
Thus, in the organic EL display device of the fifth exemplary embodiment, cavity adjustment can be easily performed, for instance, by simply increasing the film thickness of the first layer of the red-emitting organic EL device.
Since the organic EL display device of the fifth exemplary embodiment includes the red-emitting organic EL device that can achieve higher performance (especially, a decrease in voltage), specifically, both luminous efficiency and voltage suitable for practical use, the organic EL display device of the fifth exemplary embodiment can achieve higher performance.
Further, in the organic EL display device of the fifth exemplary embodiment, an emission position in the blue-emitting organic EL device is easily adjustable by providing the blue organic layer in the blue-emitting organic EL device. Further, an emission position in the green-emitting organic EL device is easily adjustable by providing the green organic layer in the green-emitting organic EL device.
An organic EL display device 100B shown in
The blue-emitting organic EL device 20B includes a blue organic layer 531 as the non-common layer between the blue emitting layer 53 and the second layer 62. In
The green-emitting organic EL device 20G includes a green organic layer 541 as the non-common layer between the green emitting layer 54 and the second layer 62. In
The second layer 62 as the common layer is preferably in direct contact with each of the blue organic layer 531, the green organic layer 541, and the first layer 61.
The second layer 62 is preferably in direct contact with the anode-side organic layer 63. The anode-side organic layer 63 is preferably in direct contact with the second layer 62 and the anode 3.
The invention is not limited to the arrangement of the organic EL display device shown in
The blue organic layer and the green organic layer are explained.
The first layer described in the first exemplary embodiment is applicable to the first layer included in the red-emitting organic EL device. The second layer described in the first exemplary embodiment is applicable to the second layer provided in a shared manner across the blue-emitting organic EL device, the green-emitting organic EL device, and the red-emitting organic EL device.
The blue organic layer contains a blue organic material. As the blue organic material, for instance, it is possible to use a material usable for the hole transporting layer (e.g., an aromatic amine compound, a carbazole derivative, and an anthracene derivative) described in the above Arrangement of Organic EL Device.
Although the blue organic material and the second compound contained in the second layer may be the same compound or different compounds, the blue organic material is preferably different from the second compound.
The blue organic material is a compound different from the host material and the blue emitting compound contained in the blue emitting layer.
The green organic layer contains a green organic material. As the green organic material, for instance, it is possible to use a material usable for the hole transporting layer (e.g., an aromatic amine compound, a carbazole derivative, and an anthracene derivative) described in the above Arrangement of Organic EL Device.
Although the green organic material and the second compound contained in the second layer may be the same compound or different compounds, the green organic material is preferably different from the second compound.
The green organic material is a compound different from the host material and the red emitting compound contained in the green emitting layer.
Although the green organic material contained in the green organic layer of the green-emitting organic EL device and the blue organic material contained in the blue organic layer of the blue-emitting organic EL device may be the same compound or different compounds, the green organic material is preferably different from the blue organic material.
As an exemplary manufacturing method of the organic EL display device of the fourth exemplary embodiment, explanation is made about a manufacturing method of the organic EL display device 100A shown in
First, the anode 3 is formed on the substrate 2A.
Subsequently, the anode-side organic layer 63 as the common layer is formed on the anode 3. The anode-side organic layer 63 provided for the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R is formed to have a constant film thickness.
Next, the second layer 62 is formed on the anode-side organic layer 63 in a region corresponding to the anode 3 of the blue-emitting organic EL device, the green-emitting organic EL device, and the red-emitting organic EL device. The second layer 62 provided for the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R is formed to have a constant film thickness.
Next, the blue emitting layer 53 is formed on the second layer 62 in a region corresponding to the anode 3 of the blue-emitting organic EL device 10B using a predetermined film-forming mask (mask for the blue-emitting organic EL device).
Next, the green emitting layer 54 is formed on the second layer 62 in a region corresponding to the anode 3 of the green-emitting organic EL device 10G using a predetermined film-forming mask (mask for the green-emitting organic EL device).
Next, the first layer 61 is formed on the second layer 62 in a region corresponding to the anode 3 of the red-emitting organic EL device 10R using a predetermined film-forming mask (mask for the red-emitting organic EL device). After forming the first layer 61, the red emitting layer 50 is formed on the first layer 61.
The blue emitting layer 53, the green emitting layer 54, and the red emitting layer 50 are formed from mutually different materials.
After the formation of the second layer 62, the order of forming the non-common layers of the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R is not particularly limited.
For instance, after forming the second layer 62, the green emitting layer 54 of the green-emitting organic EL device 10G may be formed, then the blue emitting layer 53 of the blue-emitting organic EL device 10B may be formed, and then the first layer 61 and the red emitting layer 50 of the red-emitting organic EL device 10R may be formed.
Alternatively, for instance, after forming the second layer 62, the first layer 61 and the red emitting layer 50 of the red-emitting organic EL device 10R may be formed, then the green emitting layer 54 of the green-emitting organic EL device 10G may be formed, and then the blue emitting layer 53 of the blue-emitting organic EL device 10B may be formed.
Subsequently, the electron transporting layer 8 as the common layer is formed on the blue emitting layer 53, the green emitting layer 54, and the red emitting layer 50 to extend thereover. The electron transporting layer 8 of the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R is formed to have a constant film thickness using the same material.
Subsequently, the electron injecting layer 9 as the common layer is formed on the electron transporting layer 8. The electron injecting layer 9 of the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R is formed to have a constant film thickness using the same material.
Subsequently, the cathode 4 as the common layer is formed on the electron injecting layer 9. The cathode 4 of the blue-emitting organic EL device 10B, the green-emitting organic EL device 10G, and the red-emitting organic EL device 10R is formed to have a constant film thickness using the same material.
The organic EL display device 100A shown in
The organic EL display device 100B shown in
Next, the green organic layer 541 is formed on the second layer 62 in a region corresponding to the anode 3 of the green-emitting organic EL device 20G using a predetermined film-forming mask (mask for the green-emitting organic EL device). Next, the green emitting layer 54 is formed on the green organic layer 541.
Any other manufacturing steps of the organic EL display device 100B are similar to those of the organic EL display device 100A.
In an exemplary embodiment of the organic EL display device shown in
In an exemplary embodiment of the organic EL display device shown in
A compound according to a sixth exemplary embodiment is a compound represented by a formula (10) below.
The compound according to the sixth exemplary embodiment is an exemplary arrangement of the first compound usable for the organic EL devices according to the first to third exemplary embodiments, and an exemplary arrangement of the first compound usable for the organic EL display devices according to the fourth and fifth exemplary embodiments.
In the formula (10):
L10 is a single bond, or a substituted or unsubstituted arylene group having 6 to 12 ring carbon atoms;
a substituent, if present, for L10 is an unsubstituted phenyl group;
Ar10 is a substituted or unsubstituted aryl group having 6 to 18 ring carbon atoms; and
a substituent, if present, for Ar10 is an unsubstituted phenyl group or an unsubstituted naphthyl group.
In the compound according to the sixth exemplary embodiment, L10 is preferably a single bond, a substituted or unsubstituted phenylene group, a substituted or unsubstituted biphenylene group, or a substituted or unsubstituted naphthylene group.
In the compound according to the sixth exemplary embodiment, L10 is preferably a single bond, or a substituted or unsubstituted phenylene group.
In the compound according to the sixth exemplary embodiment, Ar10 is preferably a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group, a substituted or unsubstituted naphthyl group, or a substituted or unsubstituted phenanthryl group.
In the compound according to the sixth exemplary embodiment, Ar10 is preferably a group represented by any of formulae (10a) to (27a) below, more preferably a group represented by any of the formulae (10a) to (14a), (17a), (18a), and (26a). In the formulae below, * represents a bonding position.
In the formulae (14a) to (19a) and (22a) to (27a), *C represents a bonding position to a carbon atom on a benzene ring.
In the compound according to the sixth exemplary embodiment, Ar10 is further preferably a group represented by any of formulae (10a) to (13a), (14a-1) to (18a-1), (20a) to (21a), and (26a-1) below. In the formulae below, * represents a bonding position.
In an organic EL device in an exemplary arrangement of the sixth exemplary embodiment, the first compound used in the organic EL device according to the first exemplary embodiment, the second exemplary embodiment, or the third exemplary embodiment is replaced with the compound according to the sixth exemplary embodiment (the compound represented by the formula (10)).
The compound according to the sixth exemplary embodiment allows the organic EL device to achieve higher performance (especially, a decrease in voltage), specifically, both luminous efficiency and voltage suitable for practical use.
Thus, the organic EL device in an exemplary arrangement of the sixth exemplary embodiment also achieves higher performance.
In an organic EL display device in an exemplary arrangement of the sixth exemplary embodiment, the first compound used in the organic EL display device according to the fourth exemplary embodiment or the fifth exemplary embodiment is replaced with the compound according to the sixth exemplary embodiment (the compound represented by the formula (10)).
The compound according to the sixth exemplary embodiment allows the organic EL display device to achieve higher performance (especially, a decrease in voltage), specifically, both luminous efficiency and voltage suitable for practical use.
Thus, the organic EL display device in an exemplary arrangement of the sixth exemplary embodiment also achieves higher performance.
An electronic device according to a seventh exemplary embodiment is installed with one of the organic EL devices according to the above exemplary embodiments or one of the organic EL display devices according to the above exemplary embodiments. Examples of the electronic device include a display device and a light-emitting unit. Examples of the display device include a display component (e.g., an organic EL panel module), TV, mobile phone, tablet and personal computer. Examples of the light-emitting unit include an illuminator and a vehicle light.
The scope of the invention is not limited to the above-described exemplary embodiments but includes any modification and improvement as long as such modification and improvement are compatible with the invention.
For instance, the emitting layer is not limited to a single layer, but may be provided by layering two emitting layers or multiple layers exceeding two. For instance, in some embodiments, the rest of the emitting layers is a fluorescent emitting layer or a phosphorescent emitting layer with use of emission caused by electron transfer from the triplet excited state directly to the ground state. When the organic EL device includes a plurality of emitting layers, these emitting layers may be in direct contact with each other, or may form a so-called tandem organic EL device, in which a plurality of emitting units are layered via an intermediate layer (occasionally also referred to as a charge generating layer).
Further, for instance, a blocking layer is optionally provided adjacent to a side of the emitting layer close to the cathode. The blocking layer provided in direct contact with the side of the emitting layer close to the cathode preferably blocks at least one of holes or excitons.
For instance, when the blocking layer is provided in contact with the side of the emitting layer close to the cathode, the blocking layer permits transport of electrons and blocks holes from reaching a layer provided closer to the cathode (e.g., the electron transporting layer) beyond the blocking layer. When the organic EL device includes the electron transporting layer, the blocking layer may be disposed between the emitting layer and the electron transporting layer.
Alternatively, the blocking layer may be provided adjacent to the emitting layer so that the excitation energy does not leak out from the emitting layer toward neighboring layer(s). The blocking layer blocks excitons generated in the emitting layer from being transferred to a layer(s) (e.g., the electron transporting layer and the like) closer to the electrode(s) than the blocking layer. The emitting layer is preferably in direct contact with the blocking layer.
Specific structure, shape and the like of the components in the invention may be designed in any manner as long as an object of the invention can be achieved.
Examples of the invention are described below. The invention, however, is not limited to Examples.
Structures of the first compound used for manufacturing the organic EL devices in Examples are shown below.
Structures of the second compound used for manufacturing the organic EL devices in Examples are shown below.
Structures of comparative compounds used for manufacturing organic EL devices in Comparatives are shown below.
Structures of other compounds used for manufacturing organic EL devices in Examples and Comparatives are shown below.
The organic EL devices were prepared and evaluated as follows.
A glass substrate (size: 25 mm×75 mm×1.1 mm thick, manufactured by Geomatec Co., Ltd.) having an ITO transparent electrode (anode) was ultrasonic-cleaned in isopropyl alcohol for five minutes, and then UV/ozone-cleaned for one minute. A film of ITO was 130 nm thick.
After the glass substrate having the transparent electrode line was cleaned, the glass substrate was mounted on a substrate holder of a vacuum evaporation apparatus. First, a compound HT2-1 and a compound HA were co-deposited on a surface of the glass substrate, where the transparent electrode line was provided, to cover the transparent electrode, thereby forming a 10-nm-thick hole injecting layer. The concentrations of the compound HT2-1 and the compound HA in the hole injecting layer were 97 mass % and 3 mass %, respectively.
Next, the compound HT2-1 as the second compound was vapor-deposited on the hole injecting layer to form a 130-nm-thick second layer (occasionally also referred to as a first hole transporting layer).
Next, a compound HT1-1 as the first compound was vapor-deposited on the second layer to form an 80-nm-thick first layer (occasionally also referred to as a second hole transporting layer or an electron blocking layer).
Next, a compound Matrix-1 as the compound M3, a compound TADF-1 as the compound M2, and a compound RD as the compound M1 were co-deposited on the first layer to form a 25-nm-thick emitting layer. The concentrations of the compound Matrix-1, the compound TADF-1, and the compound RD in the emitting layer were 74 mass %, 25 mass %, and 1 mass % respectively.
Next, a compound HBL was vapor-deposited on the emitting layer to form a 10-nm-thick hole blocking layer.
Next, the compound ET-1 was vapor-deposited on the hole blocking layer to form a 30-nm-thick electron transporting layer.
Next, LiF was vapor-deposited on the electron transporting layer to form a 1-nm-thick electron injecting layer.
Next, metal aluminum (Al) was vapor-deposited on the electron injecting layer to form an 80-nm-thick metal Al cathode.
A device arrangement of the organic EL device of Example 1-1 is roughly shown as follows.
ITO(130)/HT2-1:HA(10.97%:0:3%)/HT2-1(130)/HT1-1(80)/Matrix-1:TADF-1:RD(25.74%:25%:1%)/HBL(10)/ET-1(30)/LiF(1)/Al(80)
Numerals in parentheses represent a film thickness (unit: nm).
The numerals (97%:3%) represented by percentage in the same parentheses indicate a ratio (mass %) between the compound HT2-1 and the compound HA in the hole injecting layer. The numerals (74%:25%:1%) represented by percentage in the same parentheses indicate a ratio (mass %) between the compound Matrix-1, the compound TADF-1, and the compound RD in the emitting layer.
The organic EL devices of Examples 1-2 to 1-3 and Comparative 1-1 were manufactured in the same manner as that of Example 1-1 except that the first compound and the second compound used in Example 1-1 were replaced with the compounds listed in Table 1.
The organic EL devices of Comparatives 1-2 to 1-3 were manufactured in the same manner as that of Example 1-1 except that the first compound used in Example 1-1 was replaced with the compounds listed in Table 1.
The manufactured organic EL devices were evaluated as follows. Table 1 shows the results.
Voltage was applied on the organic EL devices such that a current density was 10 mA/cm2, where spectral radiance spectrum was measured by a spectroradiometer CS-2000 (manufactured by Konica Minolta, Inc.). The maximum peak wavelength λp (unit: nm) was obtained from the measured spectral radiance spectrum.
A voltage (unit: V) was measured when current was applied between the anode and the cathode such that a current density was 10 mA/cm2.
Voltage was applied on the organic EL devices such that a current density was 10 mA/cm2, where spectral radiance spectrum was measured by a spectroradiometer CS-2000 (manufactured by Konica Minolta, Inc.). The external quantum efficiency EQE (unit: %) was calculated based on the obtained spectral radiance spectra, assuming that the spectra was provided under a Lambertian radiation.
5.18 × 10−10
In the organic EL devices of Examples 1-1 to 1-3, the first layer contains the first compound satisfying Numerical Formula 1 and Numerical Formula 2, the second layer contains the second compound satisfying Numerical Formula 3, and the film thickness of the first layer is thickened (80 nm).
In the organic EL device of Comparative 1-1, the first layer contains a compound not satisfying Numerical Formula 2, the second layer contains a compound not satisfying Numerical Formula 3, and the film thickness of the first layer is thickened (80 nm).
In the organic EL device of Comparative 1-2, the first layer contains a compound not satisfying Numerical Formula 1 and the film thickness of the first layer is thickened (80 nm).
In the organic EL device of Comparative 1-3, the first layer contains a compound not satisfying Numerical Formula 2 and the film thickness of the first layer is thickened (80 nm).
The organic EL devices of Examples 1-1 to 1-3 emitted light while achieving both drive voltage (low voltage) and luminous efficiency suitable for practical use. For the organic EL devices of Comparatives 1-1 and 1-3, the luminous efficiency was suitable for practical use, but the drive voltage was too high to be practically used. For the organic EL device of Comparative 1-2, the drive voltage was suitable for practical use, but the luminous efficiency was low.
The organic EL devices were prepared and evaluated as follows.
A glass substrate (size: 25 mm×75 mm×1.1 mm thick, manufactured by Geomatec Co., Ltd.) having an ITO transparent electrode (anode) was ultrasonic-cleaned in isopropyl alcohol for five minutes, and then UV/ozone-cleaned for one minute. A film of ITO was 130 nm thick.
After the glass substrate having the transparent electrode line was cleaned, the glass substrate was mounted on a substrate holder of a vacuum evaporation apparatus. First, the compound HT2-1 and the compound HA were co-deposited on a surface of the glass substrate, where the transparent electrode line was provided, to cover the transparent electrode, thereby forming a 10-nm-thick hole injecting layer. The concentrations of the compound HT2-1 and the compound HA in the hole injecting layer were 97 mass % and 3 mass %, respectively.
Next, the compound HT2-1 as the second compound was vapor-deposited on the hole injecting layer to form a 130-nm-thick second layer (occasionally also referred to as the first hole transporting layer).
Next, the compound HT1-1 as the first compound was vapor-deposited on the second layer to form an 80-nm-thick first layer (occasionally also referred to as the second hole transporting layer or the electron blocking layer).
Next, the compound Matrix-1 as the compound M3, a compound TADF-2 as the compound M2, and the compound RD as the compound M1 were co-deposited on the first layer to form a 25-nm-thick emitting layer. The concentrations of the compound Matrix-1, the compound TADF-2, and the compound RD in the emitting layer were 74 mass %, 25 mass %, and 1 mass % respectively.
Next, the compound HBL was vapor-deposited on the emitting layer to form a 10-nm-thick hole blocking layer.
Next, a compound ET-2 and a compound Liq were co-deposited on the hole blocking layer to form a 30-nm-thick electron transporting layer. The concentrations of the compound ET-2 and the compound Liq in the electron transporting layer were 50 mass % and 50 mass %, respectively.
Next, Yb was vapor-deposited on the electron transporting layer to form a 1-nm-thick electron injecting layer.
Next, metal aluminum (Al) was vapor-deposited on the electron injecting layer to form a 50-nm-thick metal Al cathode.
A device arrangement of the organic EL device of Example 2-1 is roughly shown as follows.
ITO(130)/HT2-1:HA(10.97%0:3%)/HT2-1(130)/HT1-1(80)/Matrix-1:TADF-2:RD(25.74%:25%:1%)/HBL(10)/ET-2:Liq(30.50%:50%)/Yb(1)/Al(50)
Numerals in parentheses represent a film thickness (unit: nm).
The numerals (97%:3%) represented by percentage in the same parentheses indicate a ratio (mass %) between the compound HT2-1 and the compound HA in the hole injecting layer. The numerals (74%:25%:1%) represented by percentage in the same parentheses indicate a ratio (mass %) between the compound Matrix-1, the compound TADF-2, and the compound RD in the emitting layer. The numerals (50%:50%) represented by percentage in the same parentheses indicate a ratio (mass %) between the compound ET-2 and the compound Liq in the electron transporting layer.
The organic EL devices of Examples 2-2 to 2-3 were manufactured in the same manner as that of Example 2-1 except that the first compound used in Example 2-1 was replaced with the compounds listed in Table 2.
The organic EL devices of Examples 2-4 and 2-7 were manufactured in the same manner as that of Example 2-1 except that the second compound used in Example 2-1 was replaced with the compounds listed in Table 2.
The organic EL devices of Examples 2-5 to 2-6, Examples 2-8 to 2-9, and Comparatives 2-1 to 2-2 were manufactured in the same manner as that of Example 2-1 except that the first compound and the second compound used in Example 2-1 were replaced with the compounds listed in Table 2.
The organic EL device of Example 3-1 was manufactured in the same manner as that of Example 2-1 except that the compound Matrix-1 used in Example 2-1 was replaced with the compound listed in Table 3.
The organic EL devices of Examples 3-2 to 3-3 were manufactured in the same manner as that of Example 3-1 except that the first compound used in Example 3-1 was replaced with the compounds listed in Table 3.
The organic EL device of Example 3-4 was manufactured in the same manner as that of Example 3-1 except that the second compound used in Example 3-1 was replaced with the compound listed in Table 3.
The organic EL devices of Examples 3-5 to 3-6 and Comparatives 3-1 to 3-2 were manufactured in the same manner as that of Example 3-1 except that the first compound and the second compound used in Example 3-1 were replaced with the compounds listed in Table 3.
The manufactured organic EL devices were evaluated in the same manner as in Example 1-1. Tables 2 and 3 show the evaluation results.
5.18 × 10−10
In the organic EL devices of Examples 2-1 to 2-9, the first layer contains the first compound satisfying Numerical Formula 1 and Numerical Formula 2, the second layer contains the second compound satisfying Numerical Formula 3, and the film thickness of the first layer is thickened (80 nm).
In the organic EL devices of Comparatives 2-1 to 2-2, the first layer contains a compound not satisfying Numerical Formula 2, the second layer contains a compound not satisfying Numerical Formula 3, and the film thickness of the first layer is thickened (80 nm).
The organic EL devices of Examples 2-1 to 2-9 emitted light while achieving both drive voltage (low voltage) and luminous efficiency suitable for practical use. For the organic EL devices of Comparatives 2-1 to 2-2, the luminous efficiency was suitable for practical use, but voltage was too high to be practically used.
5.18 × 10−10
In the organic EL devices of Examples 3-1 to 3-6, the first layer contains the first compound satisfying Numerical Formula 1 and Numerical Formula 2, the second layer contains the second compound satisfying Numerical Formula 3, and the film thickness of the first layer is thickened (80 nm).
In the organic EL devices of Comparatives 3-1 to 3-2, the first layer contains a compound not satisfying Numerical Formula 2, the second layer contains a compound not satisfying Numerical Formula 3, and the film thickness of the first layer is thickened (80 nm).
The organic EL devices of Examples 3-1 to 3-6 emitted light while achieving both drive voltage (low voltage) and luminous efficiency suitable for practical use. For the organic EL devices of Comparatives 3-1 to 3-2, the luminous efficiency was suitable for practical use, but voltage was too high to be practically used.
Values of physical properties of the compounds shown in Tables 1 to 3 were measured by the following method. Tables 1 to 4 show the results.
Delayed fluorescence properties were checked by measuring transient photoluminescence (PL) using a device shown in
The fluorescence spectrum of the above sample solution was measured with a spectrofluorometer FP-8600 (manufactured by JASCO Corporation), and the fluorescence spectrum of a 9,10-diphenylanthracene ethanol solution was measured under the same conditions. Using the fluorescence area intensities of both spectra, the total fluorescence quantum yield is calculated by an equation (1) in Morris et al. J. Phys. Chem. 80 (1976) 969.
Prompt emission was observed immediately when the excited state was achieved by exciting the compound TADF-1 with a pulse beam (i.e., a beam emitted from a pulse laser) having a wavelength to be absorbed by the compound TADF-1, and Delay emission was observed not immediately when the excited state was achieved but after the excited state was achieved. The delayed fluorescence in Examples means that an amount of Delay Emission is 5% or more with respect to an amount of Prompt Emission. Specifically, provided that the amount of Prompt emission is denoted by XP and the amount of Delay emission is denoted by XD, the delayed fluorescence means that a value of XD/XP is 0.05 or more.
An amount of Prompt emission, an amount of Delay emission and a ratio between the amounts thereof can be obtained according to the method as described in “Nature 492, 234-238, 2012” (Reference Document 1). The amount of Prompt emission and the amount of Delay emission may be calculated using a device different from one described in Reference Document 1 or one shown in
Measurement for the compound TADF-2 was performed in the same manner as the compound TADF-1. It was confirmed that the amount of Delay Emission was 5% or more with respect to the amount of Prompt Emission in the compounds TADF-1 and TADF-2. Specifically, the value of XD/XP was 0.05 or more in the compounds TADF-1 and TADF-2.
The singlet energy S1 of each measurement target compound was measured according to the above-described solution method.
T77K of each measurement target compound was measured. T77K was measured by the measurement method of the energy gap T77K described in “Relationship between Triplet Energy and Energy Gap at 77K.”
T77K of the compound Matrix-1 was 2.89 eV.
T77K of the compound Matrix-2 was 2.79 eV.
ΔST was calculated based on the measured lowest singlet energy S1 and energy gap T77K at 77K. In Tables, the notation “<0.01” indicates that ΔST was less than 0.01 eV.
A toluene solution of each measurement target compound at a concentration of 5 μmol/L was prepared and put in a quartz cell. A fluorescence spectrum (ordinate axis: fluorescence intensity, abscissa axis: wavelength) of each sample was measured at a normal temperature (300K). In Examples, a fluorescence spectrum was measured with a spectrophotofluorometer (manufactured by Hitachi High-Tech Science Corporation: F-7000). It should be noted that the fluorescence spectrum measuring device may be different from the above device. A peak wavelength of a fluorescence spectrum, a luminous intensity of which is the maximum in the fluorescence spectrum, was defined as the maximum peak wavelength A.
The ionization potential Ip of each compound was measured under atmosphere using a photoelectron spectroscope (“AC-3” manufactured by RIKEN KEIKI Co., Ltd.). Specifically, the material was irradiated with light and the amount of electrons generated by charge separation was measured to measure the ionization potential of the compound. The ionization potential is occasionally referred to as Ip.
The hole mobility μh was measured using a mobility evaluation device manufactured by the following steps.
A glass substrate (size: 25 mm×75 mm×1.1 mm thick, manufactured by Geomatec Co., Ltd.) having an ITO transparent electrode (anode) was ultrasonic-cleaned in isopropyl alcohol for five minutes, and then UV-ozone-cleaned for 30 minutes. A film of ITO was 130 nm thick.
After the glass substrate was cleaned, the glass substrate was mounted on a substrate holder of a vacuum evaporation apparatus. First, the compound HA-2 was vapor-deposited on a surface of the glass substrate, where the transparent electrode line was provided, to cover the transparent electrode, thereby forming a 5-nm-thick hole injecting layer.
A compound HT-A was vapor-deposited on the formed hole injecting layer to form a 10-nm-thick hole transporting layer.
Subsequently, a compound Target to be measured for the hole mobility μh was vapor-deposited to form a 200-nm-thick measurement target layer.
Metal aluminum (Al) was vapor-deposited on this measurement target layer to form an 80-nm-thick metal cathode.
An arrangement of the mobility evaluation device above is roughly shown as follows.
ITO(130)/HA-2(5)/HT-A(10)/Target(200)/Al(80)
Numerals in parentheses represent a film thickness (nm).
Subsequently, the hole mobility is measured by the following steps using the mobility evaluation device manufactured as described above.
The mobility evaluation device was set in an impedance measurement device to perform an impedance measurement.
In the impedance measurement, a measurement frequency was swept from 1 Hz to 1 MHz. At this time, an alternating current amplitude of 0.1 V and a direct current voltage V were applied to the device.
A modulus M was calculated from a measured impedance Z using a relationship of a calculation formula (C1) below.
M=jωZ Calculation Formula (C1):
In the calculation formula (C1), j is an imaginary unit whose square is −1 and ω is an angular frequency [rad/s].
In a bode plot in which an imaginary part of the modulus M is represented by an ordinate axis and the frequency [Hz] is represented by an abscissa axis, an electrical time constant τ of the mobility evaluation device was obtained from a frequency fmax showing a peak using a calculation formula (C2) below.
τ=1/(2πf max) Calculation Formula (C2):
π in the calculation formula (C2) is a symbol representing a circumference ratio.
The hole mobility μh was calculated from a relationship of a calculation formula (C3) below using T.
μh=d2/(Vτ) Calculation Formula (C3):
d in the calculation formula (C3) is a total film thickness of organic thin film(s) forming the device. As in the arrangement of the mobility evaluation device, d=215 [nm] is satisfied.
The mobility herein is a value obtained when a square root of an electric field intensity meets E1/2=500 [V1/2/cm1/2]. The square root of the electric field intensity, E1/2, can be calculated from a relationship of a calculation formula (C4) below.
E
1/2
=V
1/2
/d
1/2 Calculation Formula (C4):
For the impedance measurement in Examples, a 1260 type by Solartron Analytical was used as the impedance measurement device, and a 1296 type dielectric constant measurement interface by Solartron Analytical was used together therewith to enhance measurement accuracy.
As the compound represented by the formula (10), a compound HT1-2 was synthesized.
Under argon atmosphere, a mixture of N-[4-(dibenzo[b,d]furan-4-yl)phenyl][1,1′:4′,1″-terphenyl]-4-amine (59.0 g, 121 mmol), 1-bromodibenzo[b,d]thiophene (35.0 g, 133 mmol), palladium acetate (0.540 g, 2.42 mmol), tri-tert-butylphosphine (0.980 g, 4.84 mmol), sodium-t-butoxide (17.4 g, 182 mmol), and xylene (940 mL) was refluxed at 100 degrees C. for 10 hours. The reaction solution was cooled to room temperature, which was then concentrated under reduced pressure. The obtained residue was refined by column chromatography and recrystallization to obtain 42.1 g of a white solid. The yield was 52%.
As a result of mass spectrum analysis, this white solid was the compound HT1-2. m/e was equal to 670 while a calculated molecular weight was 669.84.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-106074 | Jun 2021 | JP | national |
