Patent Application
20240292750
The present invention relates to an organic electroluminescence device and an electronic device.
An organic electroluminescence device (hereinafter, occasionally referred to as “organic EL device”) has found its application in a full-color display for mobile phones, televisions, and the like. When voltage is applied to 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%.
For instance, in Patent Literatures 1 and 2, various studies have been made on a compound to be used for an emitting layer of an organic EL device in order to enhance the performance of the organic EL device.
The performance of the organic EL device is evaluable in terms of, for instance, luminance, emission wavelength, chromaticity, luminous efficiency, drive voltage, and lifetime.
An object of the invention is to provide an organic electroluminescence device having a long lifetime and an electronic device including the organic electroluminescence device.
According to an aspect of the invention, there is provide an organic electroluminescence device including an emitting layer, in which the emitting layer includes at least one single layer containing a first host material, a second host material, and an emitting compound, the first host material and the second host material are mutually different, and a triplet energy of the first host material T1(H1), a triplet energy of the second host material T1(H2), and a triplet energy of the emitting compound T1(D) satisfy at least one of a relationship of a numerical formula (Numerical Formula 1) or a relationship of a numerical formula (Numerical Formula 2) below.
T
1(D)>T1(H1) (Numerical Formula 1)
T
1(D2)>T1(H2) (Numerical Formula 2)
According to another aspect of the invention, an electronic device including the organic electroluminescence device according to the aspect of the invention is provided.
According to the above aspect of the invention, an organic electroluminescence device having a longer lifetime can be provided. Also, according to the above aspect of the invention, an electronic device including this organic electroluminescence device can be provided.
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, crosslinking 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 specifically described, 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 pyridine ring has 5 ring carbon atoms, and a furan ring 4 ring carbon atoms. For instance, a 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 (e.g., an alkyl group), the number of carbon atoms of the alkyl group is not counted in the number of the ring carbon atoms. 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 is not counted as ring atoms of the pyridine ring. 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 G11B). (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.
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, 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 monovalent aryl group derived by removing one hydrogen atom from cyclic structures represented by formulae (TEMP-1) to (TEMP-15) below.
an 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 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.
a 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.
a 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.
a 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.
a (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.
a phenyldibenzofuranyl group, methyldibenzofuranyl group, t-butyldibenzofuranyl group, and monovalent residue of spiro[9H-xanthene-9,9′-[9H]fluorene].
a 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.
a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, and t-butyl group.
a 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.
a vinyl group, allyl group, 1-butenyl group, 2-butenyl group, and 3-butenyl group.
a 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.
an 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.
a cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-adamantyl group, 1-norbornyl group, and 2-norbornyl group.
a 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:
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:
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:
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:
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 “unsubstituted 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 “unsubstituted 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.
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. A 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, p3-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 heterocyclic ring 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 examples of the specific example group G1 with a hydrogen atom.
Specific examples of the aromatic heterocyclic ring include a ring formed by terminating a bond of an aromatic heterocyclic group in the specific examples 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 examples 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, the 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 ring 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;
In an exemplary embodiment, the substituent for the substituted or unsubstituted group is a group 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 ring having 5 to 50 ring atoms.
In an exemplary embodiment, the substituent for the substituted or unsubstituted group is a group 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 ring 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.”
An organic electroluminescence device according to the exemplary embodiment includes an emitting layer, in which the emitting layer includes at least one single layer containing a first host material, a second host material, and an emitting compound, the first host material and the second host material are mutually different, and a triplet energy of the first host material T1(H1), a triplet energy of the second host material T1(H2), and a triplet energy of the emitting compound T1(D) satisfy at least one of a relationship of a numerical formula (Numerical Formula 1) or a relationship of a numerical formula (Numerical Formula 2).
T
1(D)>T1(H1) (Numerical Formula 1)
T
1(D2)>T1(H2) (Numerical Formula 2)
The organic EL device according to the exemplary embodiment includes at least one single layer containing the first host material, the second host material, and the emitting compound. In the organic EL device according to the exemplary embodiment, the single layer is an emitting layer, and the first host material, the second host material, and the emitting compound are mixed in the single emitting layer. Herein, the single layer containing the first host material, the second host material, and the emitting compound is occasionally referred to as a first emitting layer. It should be noted that, even in a case where the organic EL device is referred to as including the first emitting layer, the case is not limited only to a case where the organic EL device includes a plurality of emitting layers. The organic EL device can include only the first emitting layer as the emitting layer or can further include an emitting layer other than the first emitting layer.
A triplet energy of the emitting compound contained in a single layer (first emitting layer) as the emitting layer is larger than a triplet energy of at least one of the first host material or the second host material. Since the organic EL device of the exemplary embodiment satisfies at least one of the numerical formula (Numerical Formula 1) or the numerical formula (Numerical Formula 2), excited triplet energy is likely to transfer from the emitting compound to the host materials more stable than the emitting compound. Further, in the organic EL device according to the exemplary embodiment, since the emitting layer contains the first host material and the second host material, excited singlet energy is likely to disperse in the first host material and the second host material.
It is thus considered that, according to the organic EL device of the exemplary embodiment, as compared with a case where only a single host material is contained, the excited triplet energy is likely to transfer from the emitting compound to the more stable host materials and the excited singlet energy is likely to disperse in the first host material and the second host material, thereby prolonging the lifetime.
In the organic EL device according to the exemplary embodiment, the first host material and the second host material preferably satisfy a relationship of a numerical formula (Numerical Formula 3) below.
T
1(H1)>T1(H2) (Numerical Formula 3)
Since the organic EL device of the exemplary embodiment satisfies the numerical formula (Numerical Formula 3), the excited triplet energy is likely to transfer from the emitting compound to the more stable second host material.
In the organic EL device according to the exemplary embodiment, the first host material, the second host material, and the emitting compound preferably satisfy a relationship of a numerical formula (Numerical Formula 4) below.
Since the organic EL device of the exemplary embodiment satisfies the numerical formula (Numerical Formula 4), the excited triplet energy is likely to transfer from the emitting compound to the more stable first host material, more likely to transfer to the second host material more stable than the first host material.
In the organic EL device according to the exemplary embodiment, the first host material and the second host material preferably satisfy a relationship of a numerical formula (Numerical Formula 5) below.
When the Organic EL Device of the Exemplary Embodiment Satisfies the numerical formula (Numerical Formula 5), the excited triplet energy is more likely to transfer from the first host material to the second host material.
In the organic EL device according to the exemplary embodiment, the first host material and the second host material may satisfy a relationship of at least one of a numerical formula (Numerical Formula 5A), a numerical formula (Numerical Formula 5B), or a numerical formula (Numerical Formula 5C) below.
In the organic EL device according to the exemplary embodiment, a singlet energy of the first host material S1(H1) and a singlet energy of the emitting compound S1(D1) preferably satisfy a relationship of a numerical formula (Numerical Formula 6) below.
S
1(H1)>S1(D1) (Numerical Formula 6)
The singlet energy S1 means an energy difference between the lowest singlet state and the ground state.
When the first host material and the emitting compound satisfy the relationship of the numerical formula (Numerical Formula 6), singlet excitons generated on the first host material are likely to transfer from the first host material to the emitting compound, thereby contributing to emission (preferably fluorescence) of the emitting compound.
In the organic EL device according to the exemplary embodiment, a singlet energy of the second host material S1(H2) and the singlet energy of the emitting compound S1(D1) preferably satisfy a relationship of a numerical formula (Numerical Formula 7) below.
S
1(H2)>S1(D1) (Numerical Formula 7)
When the second host material and the emitting compound satisfy the relationship of the numerical formula (Numerical Formula 7), singlet excitons generated on the second host material are likely to transfer from the second host material to the emitting compound, thereby contributing to emission (preferably fluorescence) of the emitting compound.
A method of measuring a triplet energy T1 is exemplified by a method below.
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 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). A tangent is drawn to the rise of the phosphorescence spectrum close to the short-wavelength region. An energy amount is calculated by a conversion equation (F1) below on a basis of a wavelength value λedge [nm] at an intersection of the tangent and the abscissa axis. The calculated energy amount is defined as triplet energy T1.
T
1 [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 a singlet energy S1 with use of a solution (occasionally referred to as a solution method) is exemplified by a method below.
A toluene solution of a measurement target compound at a concentration ranging from 10−5 mol/L to 10−4 mol/L is prepared and put in a quartz cell. An absorption spectrum (ordinate axis: absorption intensity, abscissa axis: wavelength) of the thus-obtained sample is measured at a normal temperature (300K). A tangent is 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 is assigned to a conversion equation (F2) below to calculate singlet energy.
S
1 [eV]=1239.85/λedge Conversion Equation (F2):
Any apparatus 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 organic EL device according to the exemplary embodiment, a single emitting layer (first emitting layer) containing the first host material, the second host material, and the emitting compound as the emitting layer preferably does not contain a metal complex.
First Host Material and Second Host Material In the organic EL device according to the exemplary embodiment, the first host material and the second host material are different compounds.
In the organic EL device according to the exemplary embodiment, the first host material and the second host material may be any compound that satisfies the relationship of at least one of the numerical formula (Numerical Formula 1) or the numerical formula (Numerical Formula 2). The first host material and the second host material are each independently selected, for instance, from the group consisting of compounds represented by formulae (1), (1X), (12X), (13X), (14X), (15X), (16X) and (2).
In the formula (1):
R101 to R110 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 substituted or unsubstituted aralkyl group having 7 to 50 carbon atoms, a group represented by —C(═O)R801, a group represented by —COOR802, a halogen atom, a cyano group, a nitro group, 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 (11);
In the first host material and the second host material according to the exemplary embodiment, R901, R902, R903, R904, R905, R906, R907, R801 and R802 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;
In the organic EL device according to the exemplary embodiment, the group represented by the formula (11) is preferably a group represented by a formula (111) below.
In the formula (111):
Among positions *1 to *8 of carbon atoms in a cyclic structure represented by a formula (111a) below in the group represented by the formula (111), L111 is bonded to one of the positions *1 to *4, R121 is bonded to each of three positions of the rest of *1 to *4, L112 is bonded to one of the positions *5 to *8, and R122 is bonded to each of three positions of the rest of *5 to *8.
For instance, in the group represented by the formula (111), when L111 is bonded to a carbon atom at a position *2 in the cyclic structure represented by the formula (111a) and L112 is bonded to a carbon atom at a position *7 in the cyclic structure represented by the formula (111a), the group represented by the formula (111) is represented by a formula (111b) below.
In the formula (111 b):
In the organic EL device according to the exemplary embodiment, the group represented by the formula (111) is preferably a group represented by the formula (111b).
In the organic EL device according to the exemplary embodiment, it is preferable that ma is 0, 1, or 2 and mb is 0, 1, or 2.
In the organic EL device according to the exemplary embodiment, it is preferable that ma is 0 or 1 and mb is 0 or 1.
In the organic EL device according to the exemplary embodiment, Ar101 is preferably a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms.
In the organic EL device according to the exemplary embodiment, Ar101 is preferably a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group, a substituted or unsubstituted pyrenyl group, a substituted or unsubstituted phenanthryl group, or a substituted or unsubstituted fluorenyl group.
In the organic EL device according to the exemplary embodiment, Ar101 is also preferably a group represented by a formula (12), a formula (13), or a formula (14) below.
In the formulae (12), (13), and (14):
In the organic EL device according to the exemplary embodiment, the compound represented by the formula (1) is preferably represented by a formula (101) below.
In the formula (101):
In the organic EL device according to the exemplary embodiment, L101 is preferably a single bond or a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms.
In the organic EL device according to the exemplary embodiment, the compound represented by the formula (1) is preferably represented by a formula (102) below.
In the formula (102):
In the compound represented by the formula (102), it is preferable that ma is 0, 1, or 2 and mb is 0, 1, or 2.
In the compound represented by the formula (102), it is preferable that ma is 0 or 1 and mb is 0 or 1.
In the organic EL device according to the exemplary embodiment, it is preferable that two or more of R101 to R110 are each a group represented by the formula (11).
In the organic EL device according to the exemplary embodiment, it is preferable that two or more of R101 to R110 are each a group represented by the formula (11) and Ar101 is a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms.
In the organic EL device according to the exemplary embodiment, it is preferable that Ar101 is not a substituted or unsubstituted pyrenyl group, L101 is not a substituted or unsubstituted pyrenylene group, and a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms as R101 to R110 not being a group represented by the formula (11) is not a substituted or unsubstituted pyrenyl group.
In the organic EL device according to the exemplary embodiment, R101 to R110 not being a group represented by the formula (11) are preferably 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.
In the organic EL device according to the exemplary embodiment, R101 to R110 not being a group represented by the formula (11) are preferably each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 3 to 50 ring carbon atoms.
In the organic EL device according to the exemplary embodiment, R101 to R110 not being the group represented by the formula (11) are preferably each a hydrogen atom.
In the formula (1X):
In the organic EL device according to the exemplary embodiment, the group represented by the formula (11X) is preferably a group represented by the formula (111X).
In the formula (111X):
Among positions *1 to *8 of carbon atoms in a cyclic structure represented by a formula (111aX) below in the group represented by the formula (111X), L111 is bonded to one of the positions *1 to *4, R141 is bonded to each of three positions of the rest of *1 to *4, L112 is bonded to one of the positions *5 to *8, and R142 is bonded to each of three positions of the rest of *5 to *8.
For instance, in the group represented by the formula (111X), when L111 is bonded to a carbon atom at *2 in the cyclic structure represented by the formula (111aX) and L112 is bonded to a carbon atom at *7 in the cyclic structure represented by the formula (111aX), the group represented by the formula (111X) is represented by a formula (111bX) below.
In the formula (111bX):
In the organic EL device according to the exemplary embodiment, the group represented by the formula (111X) is preferably a group represented by the formula (111bX).
In the compound represented by the formula (1X), preferably, ma is 1 or 2 and mb is 1 or 2.
In the compound represented by the formula (1X), preferably, ma is 1 and mb is 1.
In the compound represented by the formula (1X), Ar101 is preferably a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms.
In the compound represented by the formula (1X), Ar101 is preferably a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted terphenyl group, a substituted or unsubstituted benz[a]anthryl group, a substituted or unsubstituted pyrenyl group, a substituted or unsubstituted phenanthryl group, or a substituted or unsubstituted fluorenyl group.
The compound represented by the formula (1X) is also preferably represented by a formula (101X) below.
In the formula (101X):
In the compound represented by the formula (1X), L101 is preferably a single bond or a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms.
The compound represented by the formula (1X) is also preferably represented by a formula (102X) below.
In the formula (102X):
In the compound represented by the formula (1X), preferably, ma is 1 or 2 and mb is 1 or 2 in the formula (102X).
In the compound represented by the formula (1X), preferably, ma is 1 and mb is 1 in the formula (102X).
In the compound represented by the formula (1X), the group represented by the formula (11X) is also preferably a group represented by a formula (11AX) or a group represented by a formula (11BX) below.
In the formulae (11AX) and (11BX):
The compound represented by the formula (1X) is also preferably represented by a formula (103X) below.
In the formula (103X):
In the compound represented by the formula (1X), L131 is also preferably a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms.
In the compound represented by the formula (1X), L132 is also preferably a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms.
In the compound represented by the formula (1X), two or more of R101 to R112 are each also preferably a group represented by the formula (11X).
In the compound represented by the formula (1X), it is preferable that two or more of R101 to R112 are each a group represented by the formula (11X) and Ar101 in the formula (11X) is a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms.
In the compound represented by the formula (1X), it is also preferable that Ar101 is not a substituted or unsubstituted benz[a]anthryl group, L101 is not a substituted or unsubstituted benz[a]anthrylene group, and a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms as R101 to R110 not being a group represented by the formula (11X) is not a substituted or unsubstituted benz[a]anthryl group.
In the compound represented by the formula (1X), R101 to R112 not being a group represented by the formula (11X) are preferably 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.
In the compound represented by the formula (1X), R101 to R112 not being a group represented by the formula (11X) are preferably each a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 3 to 50 ring carbon atoms.
In the compound represented by the formula (1X), R101 to R112 not being the group represented by the formula (11X) are preferably each a hydrogen atom.
In the formula (12X):
In the formula (12X), combinations of adjacent two of R1201 to R1210 refer to a combination of R1201 and R1202, a combination of R1202 and R1203, a combination of R1203 and R1204, a combination of R1204 and R1205, a combination of R1205 and R1206, a combination of R1207 and R1208, a combination of R1208 and R1209, and a combination of R1209 and R1210.
In the formula (13X):
In the organic EL device according to the exemplary embodiment, none of combinations of adjacent two or more of R1301 to R1310 not being the group represented by the formula (131) are bonded to each other. Combinations of adjacent two of R1301 to R1310 in the formula (13X) refer to a combination of R1301 and R1302, a combination of R1302 and R1303, a combination of R1303 and R1304, a combination of R1304 and R1305, a combination of R1305 and R1306, a combination of R1307 and R1308, a combination of R1308 and R1309, and a combination of R1309 and R1310.
In the formula (14X):
In the formula (15X):
In the formula (16X):
In the organic EL device according to the exemplary embodiment, also preferably, the first host material has, in a molecule, a linking structure including a benzene ring and a naphthalene ring linked to each other with a single bond, in which the benzene ring and the naphthalene ring in the linking structure are each independently fused or not fused with a further monocyclic ring or fused ring, and the benzene ring and the naphthalene ring in the linking structure are further linked to each other by cross-linking at at least one site other than the single bond.
When the first host material has the linking structure including such cross-linking, deterioration in the chromaticity of the organic EL device is expected to be inhibited.
The first host material in the above case is only required to have a linking structure as the minimum unit in a molecule, the linking structure including a benzene ring and a naphthalene ring linked to each other with a single bond (occasionally referred to as a benzene-naphthalene linking structure), the linking structure being as represented by a formula (X1) or a formula (X2) below. Further, the benzene ring may be fused with a monocyclic ring or fused ring, and the naphthalene ring may be fused with a monocyclic ring or fused ring. For instance, also in a case where the first host material has, in a molecule, a linking structure including a naphthalene ring and a naphthalene ring linked to each other with a single bond (occasionally referred to as a naphthalene-naphthalene linking structure) and being as represented by a formula (X3), a formula (X4), or a formula (X5) below, the naphthalene-naphthalene linking structure is regarded as including the benzene-naphthalene linking structure since one of the naphthalene rings includes a benzene ring.
In the organic EL device according to the exemplary, the cross-linking also preferably includes a double. Specifically, the first host material also preferably has a structure in which the benzene ring and the naphthalene ring are further linked to each other at any other site than the single bond by the cross-linking structure including a double bond.
Assuming that the benzene ring and the naphthalene ring in the benzene-naphthalene linking structure are further linked to each other at at least one site other than the single bond by cross-linking, for instance, a linking structure (fused ring) represented by a formula (X11) below is obtained in a case of the formula (X1), and a linking structure (fused ring) represented by a formula (X31) below is obtained in a case of the formula (X3).
Assuming that the benzene ring and the naphthalene ring in the benzene-naphthalene linking structure are further linked to each other at any other site than the single bond by cross-linking including a double bond, for instance, a linking structure (fused ring) represented by a formula (X12) below is obtained in a case of the formula (X1), a linking structure (fused ring) represented by a formula (X21) or formula (X22) below is obtained in a case of the formula (X2), a linking structure (fused ring) represented by a formula (X41) below is obtained in a case of the formula (X4), and a linking structure (fused ring) represented by a formula (X51) below is obtained in a case of the formula (X5).
Assuming that the benzene ring and the naphthalene ring in the benzene-naphthalene linking structure are further linked to each other at at least one site other than the single bond by cross-linking including a hetero atom (e.g., an oxygen atom), for instance, a linking structure (fused ring) represented by a formula (X13) below is obtained in a case of the formula (X1).
In the organic EL device according to the exemplary embodiment, also preferably, the first host material has, in a molecule, a biphenyl structure including a first benzene ring and a second benzene ring linked to each other with a single bond, and the first benzene ring and the second benzene ring in the biphenyl structure are further linked to each other by cross-linking at at least one site other than the single bond.
In the organic EL device according to the exemplary embodiment, also preferably, the first benzene ring and the second benzene ring in the biphenyl structure are further linked to each other by the cross-linking at one site other than the single bond. When the first host material has the biphenyl structure including such cross-linking, deterioration in the chromaticity of the organic EL device is expected to be inhibited.
In the organic EL device according to the exemplary, the cross-linking also preferably includes a double.
In the organic EL device according to the exemplary embodiment, the cross-linking also preferably includes no double bond.
Also preferably, the first benzene ring and the second benzene ring in the biphenyl structure are further linked to each other by the cross-linking at two sites other than the single bond.
In the organic EL device according to the exemplary embodiment, also preferably, the first benzene ring and the second benzene ring in the biphenyl structure are further linked to each other by the cross-linking at two sites other than the single bond, and the cross-linking includes no double bond. When the first host material has the biphenyl structure including such cross-linking, deterioration in the chromaticity of the organic EL device is expected to be inhibited.
For instance, assuming that the first benzene ring and the second benzene ring in the biphenyl structure represented by a formula (BP1) below are further linked to each other by cross-linking at at least one site other than the single bond, the biphenyl structure is exemplified by linking structures (fused rings) represented by formulae (BP11) to (BP15) below.
The formula (BP11) represents a linking structure in which the first benzene ring and the second benzene ring are linked to each other at one site other than the single bond by cross-linking including no double bond.
The formula (BP12) represents a linking structure in which the first benzene ring and the second benzene ring are linked to each other at one site other than the single bond by cross-linking including a double bond.
The formula (BP13) represents a linking structure in which the first benzene ring and the second benzene ring are linked to each other at two sites other than the single bond by cross-linking including no double bond.
The formula (BP14) represents a linking structure in which the first benzene ring and the second benzene ring are linked to each other by cross-linking including no double bond at one of two sites other than the single bond, and the first benzene ring and the second benzene ring are linked to each other by cross-linking including a double bond at the other of the two sites other than the single bond.
The formula (BP15) represents a linking structure in which the first benzene ring and the second benzene ring are linked to each other at two sites other than the single bond by cross-linking including a double bond.
In the first host material and the second host material, the groups specified to be “substituted or unsubstituted” are preferably each an “unsubstituted” group.
Compounds represented by formulae (1), (1X), (12X), (13X), (14X), (15X), and (16X) can also be produced based on a known method through a known alternative reaction using a known material(s) tailored for the target compound.
Specific examples of the compounds represented by the formulae (1), (1X), (12X), (13X), (14X), (15X), and (16X) include compounds shown below. However, the invention is not limited to the specific examples of the compounds. In the specific examples of the compounds herein, D represents a deuterium atom, Me represents a methyl group, and tBu represents a tert-butyl group.
In the formula (2):
In a compound represented by the formula (2) according to the exemplary embodiment, R901, R902, R903, R904, R905, R906, R907, R801 and R802 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;
In the organic EL device according to the exemplary embodiment, it is preferable that R201 to R208 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)R801, a group represented by —COOR802, a halogen atom, a cyano group, or a nitro group; L201 and L202 are each independently a single bond, a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted divalent heterocyclic group having 5 to 50 ring atoms; and Ar201 and Ar202 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.
In the organic EL device according to the exemplary embodiment, it is preferable that L201 and L202 are each independently a single bond, or a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms; and Ar201 and Ar202 are each independently a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms.
In the organic EL device according to the exemplary embodiment, Ar201 and Ar202 are preferably each independently a phenyl group, naphthyl group, phenanthryl group, biphenyl group, terphenyl group, diphenylfluorenyl group, dimethylfluorenyl group, benzodiphenylfluorenyl group, benzodimethylfluorenyl group, dibenzofuranyl group, dibenzothienyl group, naphthobenzofuranyl group, or naphthobenzothienyl group.
In the organic EL device according to the exemplary embodiment, the compound represented by the formula (2) is preferably a compound represented by a formula (201), a formula (202), a formula (203), a formula (204), a formula (205), a formula (206), a formula (207), a formula (208), or a formula (209) below.
In the formulae (201) to (209):
The second compound represented by the formula (2) is also preferably a compound represented by a formula (221), a formula (222), a formula (223), a formula (224), a formula (225), a formula (226), a formula (227), a formula (228), or a formula (229) below.
In the formulae (221), (222), (223), (224), (225), (226), (227), (228) and (229):
The second compound represented by the formula (2) is also preferably a compound represented by a formula (241), a formula (242), a formula (243), a formula (244), a formula (245), a formula (246), a formula (247), a formula (248), or a formula (249) below.
In the formulae (241), (242), (243), (244), (245), (246), (247), (248) and (249):
In the compound represented by the formula (2), R201 to R208 are preferably 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, or a group represented by —Si(R901)(R902)(R903).
It is preferable that L201 is a single bond or an unsubstituted arylene group having 6 to 22 ring carbon atoms and Ar201 is a substituted or unsubstituted aryl group having 6 to 22 ring carbon atoms.
In the organic EL device of the exemplary embodiment, it is also preferable that R201 to R208 in the compound represented by the formula (2) 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, or a group represented by —Si(R901)(R902)(R903).
In the organic EL device according to the exemplary embodiment, R201 to R208 in the compound represented by the formula (2) are preferably each a hydrogen atom.
Production Method of Compound Represented by Formula (2) A compound represented by the formula (2) can be produced by a known method. A compound represented by the formula (2) can also be produced based on a known method through a known alternative reaction using a known material(s) tailored for the target compound.
Specific examples of the compound represented by the formula (2) include compounds shown below. However, the invention is by no means limited to the specific examples.
In the organic EL device according to the exemplary embodiment, the first host material is also preferably any compound selected from the group consisting of a compound represented by the formula (1), a compound represented by the formula (1X), a compound represented by the formula (12X), a compound represented by the formula (13X), a compound represented by the formula (14X), a compound represented by the formula (15X), and a compound represented by the formula (16X).
In the organic EL device according to the exemplary embodiment, the first host material is also preferably a pyrene derivative.
In the organic EL device according to the exemplary embodiment, the first host material is also preferably a benzoxanthene derivative.
In the organic EL device of the exemplary embodiment, the first host material is also preferably any compound selected from the group consisting of a compound represented by the formula (1) and a compound represented by the formula (14X).
In the organic EL device according to the exemplary embodiment, the second host material is also preferably an anthracene derivative.
In the organic EL device of the exemplary embodiment, the second host material is also preferably any compound selected from the group consisting of a compound represented by the formula (2).
Herein, a single layer (first emitting layer) containing the first host material, the second host material, and the emitting compound as the emitting layer may include, for instance, the first host material and the second host material in total at 50 mass % or more, 60 mass % or more, 70 mass % or more, 80 mass % or more, 90 mass % or more, or 95 mass % or more, with respect to the total mass of the single layer (first emitting layer).
In the organic EL device according to the exemplary embodiment, the emitting compound is different from the first host material and the second host material.
In the organic EL device according to the exemplary embodiment, the emitting compound preferably emits light having a maximum peak wavelength of 500 nm or less, more preferably emits light having a maximum peak wavelength of 480 nm or less.
In the organic EL device according to the exemplary embodiment, the emitting compound preferably emits light having a maximum peak wavelength of 430 nm or more.
In the organic EL device according to the exemplary embodiment, the emitting compound preferably emits fluorescence having a maximum peak wavelength of 500 nm or less, more preferably emits fluorescence having a maximum peak wavelength of 480 nm or less.
In the organic EL device according to the exemplary embodiment, the emitting compound preferably emits fluorescence having a maximum peak wavelength of 430 nm or more.
A measurement method of the maximum peak wavelength of the compound is as follows. A toluene solution of a measurement target compound at a concentration of 5 μmol/L is prepared and put in a quartz cell. An emission spectrum (ordinate axis: luminous intensity, abscissa axis: wavelength) of each of the samples is measured at a normal temperature (300K). The emission spectrum can be measured using a spectrophotometer (machine name: F-7000) produced by Hitachi High-Tech Science Corporation. It should be noted that the apparatus for measuring the emission spectrum is not limited to the apparatus used herein.
A peak wavelength of the emission spectrum exhibiting the maximum luminous intensity is defined as the maximum peak wavelength. Herein, the maximum peak wavelength is occasionally referred to as a maximum fluorescence peak wavelength (FL-peak).
In an exemplary arrangement, the emitting compound is not a metal complex.
In an exemplary arrangement, the emitting compound is not a complex.
In the organic EL device according to the exemplary embodiment, the emitting compound, which is not particularly limited, is at least one compound selected from the group consisting of a compound represented by a formula (4) below, a compound represented by a formula (5) below, a compound represented by a formula (6) below, a compound represented by a formula (7) below, a compound represented by a formula (8) below, a compound represented by a formula (9) below, and a compound represented by a formula (10) below.
The compound represented by the formula (4) will be described below.
In the formula (4):
In the organic EL device according to the exemplary embodiment, R901, R902, R903, R904, R905, R906, and R907 in the emitting compound 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;
The “aromatic hydrocarbon ring” for the A1 ring and A2 ring has the same structure as a compound formed by introducing a hydrogen atom to the “aryl group” described above.
Ring atoms of the “aromatic hydrocarbon ring” for the A1 ring and A2 ring include two carbon atoms on a fused bicyclic structure at the center of the formula (4).
Specific examples of the “substituted or unsubstituted aromatic hydrocarbon ring having 6 to 50 ring carbon atoms” include a compound formed by introducing a hydrogen atom to the “aryl group” described in the specific example group G1.
The “heterocycle” for the A1 ring and A2 ring has the same structure as a compound formed by introducing a hydrogen atom to the “heterocyclic group” described above.
Ring atoms of the “heterocycle” for the A1 ring and A2 ring include two carbon atoms on a fused bicyclic structure at the center of the formula (4).
Specific examples of the “substituted or unsubstituted heterocycle having 5 to 50 ring atoms” include a compound formed by introducing a hydrogen atom to the “heterocyclic group” described in the specific example group G2.
Rb is bonded to any one of carbon atoms forming the aromatic hydrocarbon ring as the A1 ring or any one of atoms forming the heterocycle as the A1 ring.
Rc is bonded to any one of carbon atoms forming the aromatic hydrocarbon ring as the A2 ring or any one of atoms forming the heterocycle as the A2 ring.
At least one of Ra, Rb, or Rc is preferably a group represented by a formula (4a) below. More preferably, at least two of Ra, Rb, or Rc are each a group represented by the formula (4a).
In the formula (4a):
In the formula (4b):
In an exemplary embodiment, the compound represented by the formula (4) is represented by a formula (42) below.
In the formula (42):
At least one of R401 to R411 is preferably a group represented by the formula (4a). More preferably, at least two of R401 to R411 are each a group represented by the formula (4a).
R404 and R411 are preferably each a group represented by the formula (4a).
In an exemplary embodiment, the compound represented by the formula (4) is a compound formed by bonding a structure represented by a formula (4-1) or a formula (4-2) below to the A1 ring.
Further, in an exemplary embodiment, the compound represented by the formula (42) is a compound formed by bonding the structure represented by the formula (4-1) or the formula (4-2) to a ring bonded to R404 to R407.
In the formula (4-1), two bonds * are each independently bonded to a ring-forming carbon atom of the aromatic hydrocarbon ring or a ring atom of the heterocycle as the A1 ring in the formula (4) or bonded to one of R404 to R407 in the formula (42);
In an exemplary embodiment, the compound represented by the formula (4) is a compound represented by a formula (41-3), a formula (41-4) or a formula (41-5) below.
In the formulae (41-3), (41-4), and (41-5):
In an exemplary embodiment, a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 50 ring carbon atoms as the A1 ring in the formula (41-5) is a substituted or unsubstituted naphthalene ring or a substituted or unsubstituted fluorene ring.
In an exemplary embodiment, a substituted or unsubstituted heterocycle having 5 to 50 ring atoms as the A1 ring in the formula (41-5) is a substituted or unsubstituted dibenzofuran ring, a substituted or unsubstituted carbazole ring, or a substituted or unsubstituted dibenzothiophene ring.
In an exemplary embodiment, the compound represented by the formula (4) or the formula (42) is selected from the group consisting of compounds represented by formulae (461) to (467) below.
In the formulae (461), (462), (463), (464), (465), (466), and (467):
In an exemplary embodiment, at least one combination of adjacent two or more of R401 to R411 in the compound represented by the formula (42) are mutually bonded to form a substituted or unsubstituted monocyclic ring, or mutually bonded to form a substituted or unsubstituted fused ring. This exemplary embodiment will be described in detail below as a compound represented by a formula (45) below.
The compound represented by the formula (45) will be described below.
In the formula (45):
In the formula (45), Rn and Rn+1 (n being an integer selected from 461, 462, 464 to 466, and 468 to 470) are mutually bonded to form a substituted or unsubstituted monocyclic ring or fused ring together with two ring-forming carbon atoms bonded to Rn and Rn+1. The ring is preferably formed of atoms selected from the group consisting of a carbon atom, an oxygen atom, a sulfur atom, and a nitrogen atom, and is made of preferably 3 to 7 atoms, more preferably 5 or 6 atoms.
The number of the above cyclic structures in the compound represented by the formula (45) is, for instance, 2, 3, or 4. The two or more of the cyclic structures may be present on the same benzene ring on the basic skeleton represented by the formula (45) or may be present on different benzene rings. For instance, when three cyclic structures are present, each of the cyclic structures may be present on the corresponding one of the three benzene rings of the formula (45).
Examples of the above cyclic structures in the compound represented by the formula (45) include structures represented by formulae (451) to (460) below.
In the formulae (451) to (457):
In the formulae (458) to (460):
In the formula (45), preferably, at least one of R462, R464, R465, R470 or R471 (preferably, at least one of R462, R465 or R470, more preferably R462) is a group forming no cyclic structure.
(i) A substituent, if present, for a cyclic structure formed by Rn and Rn+1 in the formula (45), (ii) R461 to R471 forming no cyclic structure in the formula (45), and (iii) R4501 to R4514, R4515 to R4525 in the formulae (451) to (460) are preferably each independently any one of groups selected from the group consisting of 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 group represented by —N(R906)(R907), 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 groups represented by formulae (461) to (464) below.
In the formulae (461) to (464):
In an exemplary embodiment, the compound represented by the formula (45) is represented by one of formulae (45-1) to (45-6) below.
In the formulae (45-1) to (45-6):
In an exemplary embodiment, the compound represented by the formula (45) is represented by one of formulae (45-7) to (45-12) below.
In the formulae (45-7) to (45-12):
In an exemplary embodiment, the compound represented by the formula (45) is represented by one of formulae (45-13) to (45-21) below.
In the formulae (45-13) to (45-21):
When the ring g or the ring h each further has a substituent, examples of the substituent include 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 group represented by the formula (461), a group represented by the formula (463), and a group represented by the formula (464).
In an exemplary embodiment, the compound represented by the formula (45) is represented by one of formulae (45-22) to (45-25) below.
In the formulae (45-22) to (45-25):
In an exemplary embodiment, the compound represented by the formula (45) is represented by a formula (45-26) below.
In the formula (45-26):
Specific examples of the compound represented by the formula (4) include compounds shown below. In the specific examples below, Ph represents a phenyl group, and D represents a deuterium atom.
The compound represented by the formula (5) will be described below. The compound represented by the formula (5) corresponds to a compound represented by the formula (41-3).
In the formula (5):
“A combination of adjacent two or more of R501 to R507 and R511 to R517” refers to, for instance, a combination of R501 and R502, a combination of R502 and R503, a combination of R503 and R504, a combination of R505 and R506, a combination of R506 and R507, and a combination of R501, R502, and R503.
In an exemplary embodiment, at least one, preferably two of R501 to R507 or R511 to R517 are each a group represented by —N(R906)(R907).
In an exemplary embodiment, R501 to R507 and R511 to R517 are each independently a hydrogen atom, 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 an exemplary embodiment, the compound represented by the formula (5) is a compound represented by a formula (52) below.
In the formula (52):
In an exemplary embodiment, the compound represented by the formula (5) is a compound represented by a formula (53) below.
In the formula (53), R551, R552 and R561 to R564 each independently represent the same as R551, R552 and R561 to R564 in the formula (52).
In an exemplary embodiment, R561 to R564 in the formulae (52) and (53) are each independently a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms (preferably a phenyl group).
In an exemplary embodiment, R521 and R522 in the formula (5) and R551 and R552 in the formulae (52) and (53) are each a hydrogen atom.
In an exemplary embodiment, the substituent for the “substituted or unsubstituted” group in the formulae (5), (52) and (53) is 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 aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms.
Specific Examples of Compound Represented by Formula (5) Specific examples of the compound represented by the formula (5) include compounds shown below.
The compound represented by the formula (6) will be described below.
In the formula (6):
The ring a, ring b and ring c are each a ring (a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocycle having 5 to 50 ring atoms) fused with a fused bicyclic structure formed of a boron atom and two nitrogen atoms at the center of the formula (6).
The “aromatic hydrocarbon ring” for the rings a, b, and c has the same structure as a compound formed by introducing a hydrogen atom to the “aryl group” described above.
Ring atoms of the “aromatic hydrocarbon ring” for the ring a include three carbon atoms on the fused bicyclic structure at the center of the formula (6).
Ring atoms of the “aromatic hydrocarbon ring” for the rings b and c include two carbon atoms on the fused bicyclic structure at the center of the formula (6).
Specific examples of the “substituted or unsubstituted aromatic hydrocarbon ring having 6 to 50 ring carbon atoms” include a compound formed by introducing a hydrogen atom to the “aryl group” described in the specific example group G1.
The “heterocycle” for the rings a, b, and c has the same structure as a compound formed by introducing a hydrogen atom to the “heterocyclic group” described above.
Ring atoms of the “heterocycle” for the ring a include three carbon atoms on the fused bicyclic structure at the center of the formula (6). Ring atoms of the “heterocycle” for the rings b and c include two carbon atoms on the fused bicyclic structure at the center of the formula (6). Specific examples of the “substituted or unsubstituted heterocycle having 5 to 50 ring atoms” include a compound formed by introducing a hydrogen atom to the “heterocyclic group” described in the specific example group G2.
R601 and R602 may be each independently bonded with the ring a, ring b, or ring c to form a substituted or unsubstituted heterocycle. The “heterocycle” in this arrangement includes a nitrogen atom on the fused bicyclic structure at the center of the formula (6). The heterocycle in the above arrangement optionally includes a hetero atom other than the nitrogen atom. R601 and R602 being bonded with the ring a, ring b, or ring c specifically means that atoms forming R601 and R602 are bonded with atoms forming the ring a, ring b, or ring c. For instance, R601 may be bonded with the ring a to form a bicyclic (or tri-or-more cyclic) fused nitrogen-containing heterocycle, in which the ring including R601 and the ring a are fused. Specific examples of the nitrogen-containing heterocycle include a compound corresponding to the nitrogen-containing bi(or-more)cyclic fused heterocyclic group in the specific example group G2.
The same applies to R601 bonded with the ring b, R602 bonded with the ring a, and R602 bonded with the ring c.
In an exemplary embodiment, the ring a, ring b and ring c in the formula (6) are each independently a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 50 ring carbon atoms.
In an exemplary embodiment, the ring a, ring b and ring c in the formula (6) are each independently a substituted or unsubstituted benzene ring or a substituted or unsubstituted naphthalene ring.
In an exemplary embodiment, R601 and R602 in the formula (6) 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, preferably a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms.
In an exemplary embodiment, the compound represented by the formula (6) is a compound represented by a formula (62) below.
In the formula (62):
R601A and R602A in the formula (62) are groups corresponding to R601 and R602 in the formula (6), respectively.
For instance, R601A and R611 are optionally bonded with each other to form a bicyclic (or tri-or-more cyclic) fused nitrogen-containing heterocycle, in which the ring including R601A and R611 and a benzene ring corresponding to the ring a are fused. Specific examples of the nitrogen-containing heterocycle include a compound corresponding to the nitrogen-containing bi(or-more)cyclic fused heterocyclic group in the specific example group G2. The same applies to R601A bonded with R621, R602A bonded with R613, and R602A bonded with R614.
At least one combination of adjacent two or more of R611 to R621 are mutually bonded to form a substituted or unsubstituted monocyclic ring, or mutually bonded to form a substituted or unsubstituted fused ring.
For instance, R611 and R612 are optionally mutually bonded to form a structure in which a benzene ring, indole ring, pyrrole ring, benzofuran ring, benzothiophene ring or the like is fused to the six-membered ring bonded with R611 and R612, the resultant fused ring forming a naphthalene ring, carbazole ring, indole ring, dibenzofuran ring, or dibenzothiophene ring, respectively.
In an exemplary embodiment, R611 to R621 not contributing to ring formation 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 an exemplary embodiment, R611 to R621 not contributing to ring formation are each independently a hydrogen atom, 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 an exemplary embodiment, R611 to R621 not contributing to ring formation are each independently a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms.
In an exemplary embodiment, R611 to R621 not contributing to ring formation are each independently a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, and at least one of R611 to R621 is a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms.
In an exemplary embodiment, the compound represented by the formula (62) is a compound represented by a formula (63) below.
In the formula (63):
In an exemplary embodiment, R631 to R651 not contributing to ring formation 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 an exemplary embodiment, R631 to R651 not contributing to ring formation are each independently a hydrogen atom, 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 an exemplary embodiment, R631 to R651 not contributing to ring formation are each independently a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms.
In an exemplary embodiment, R631 to R651 not contributing to ring formation are each independently a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, and at least one of R631 to R651 is a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms.
In an exemplary embodiment, the compound represented by the formula (63) is a compound represented by a formula (63A) below.
In the formula (63A):
In an exemplary embodiment, R661 to R665 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 an exemplary embodiment, R661 to R665 are each independently a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms.
In an exemplary embodiment, the compound represented by the formula (63) is a compound represented by a formula (63B) below.
In the formula (63B):
In an exemplary embodiment, the compound represented by the formula (63) is a compound represented by a formula (63B′) below.
In the formula (63B′), R672 to R675 each independently represent the same as R672 to R675 in the formula (63B).
In an exemplary embodiment, at least one of R671 to R675 is 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 group represented by —N(R906)(R907), or a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms.
In an exemplary embodiment: R672 is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a group represented by —N(R906)(R907), or a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms; and
In an exemplary embodiment, the compound represented by the formula (63) is a compound represented by a formula (63C) below.
In the formula (63C):
In an exemplary embodiment, the compound represented by the formula (63) is a compound represented by a formula (63C′) below.
In the formula (63C′), R683 to R686 each independently represent the same as R683 to R686 in the formula (63C).
In an exemplary embodiment, R681 to R686 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 an exemplary embodiment, R681 to R686 are each independently a substituted or unsubstituted alkyl group having 6 to 50 carbon atoms.
The compound represented by the formula (6) is producible by initially bonding the ring a, ring b and ring c with linking groups (a group including N—R601 and a group including N—R602) to form an intermediate (first reaction), and bonding the ring a, ring b and ring c with a linking group (a group including a boron atom) to form a final product (second reaction). In the first reaction, an amination reaction (e.g. Buchwald-Hartwig reaction) is applicable. In the second reaction, Tandem Hetero-Friedel-Crafts Reactions or the like is applicable.
Specific examples of the compound represented by the formula (6) are shown below. It should however be noted that these specific examples are merely exemplary and do not limit the compound represented by the formula (6).
The compound represented by the formula (7) will be described below.
In the formula (7):
In the formula (7), each of the p ring, q ring, r ring, s ring, and t ring is fused with an adjacent ring(s) sharing two carbon atoms. The fused position and orientation are not limited but may be defined as required.
In an exemplary embodiment, in the formula (72) or the formula (73) representing the r ring, m1=0 or m2=0 is satisfied.
In an exemplary embodiment, the compound represented by the formula (7) is represented by any one of formulae (71-1) to (71-6) below.
In the formulae (71-1) to (71-6), R701, X7, Ar701, Ar702, L701, m1 and m3 respectively represent the same as R701, X7, Ar701, Ar702, L701, m1 and m3 in the formula (7).
In an exemplary embodiment, the compound represented by the formula (7) is represented by any one of formulae (71-11) to (71-13) below.
In the formulae (71-11) to (71-13), R701, X7, Ar701, Ar702, L701, m1, m3 and m4 respectively represent the same as R701, X7, Ar701, Ar702, L701, m1, m3 and m4 in the formula (7).
In an exemplary embodiment, the compound represented by the formula (7) is represented by any one of formulae (71-21) to (71-25) below.
In the formulae (71-21) to (71-25), R701, X7, Ar701, Ar702, L701, m1 and m4 respectively represent the same as R701, X7, Ar701, Ar702, L701, m1 and m4 in the formula (7).
In an exemplary embodiment, the compound represented by the formula (7) is represented by any one of formulae (71-31) to (71-33) below.
In the formulae (71-31) to (71-33), R701, X7, Ar701, Ar702, L701, and m2 to m4 respectively represent the same as R701, X7, Ar701, Ar702, L701, and m2 to m4 in the formula (7).
In an exemplary embodiment, Ar701 and Ar702 are each independently a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms.
In an exemplary embodiment, one of Ar701 and Ar702 is a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, and the other of Ar701 and Ar702 is a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms.
Specific Examples of Compound Represented by Formula (7) Specific examples of the compound represented by the formula (7) include compounds shown below.
The compound represented by the formula (8) will be described below.
In the formula (8):
At least one of R801 to R804 not forming the divalent group represented by the formula (82) or R11 to R814 is a monovalent group represented by a formula (84) below;
In the formula (84):
In the formula (8), the positions for the divalent group represented by the formula (82) and the divalent group represented by the formula (83) to be formed are not specifically limited but the divalent groups may be formed at any possible positions on R801 to R808.
In an exemplary embodiment, the compound represented by the formula (8) is represented by any one of formulae (81-1) to (81-6) below.
In the formulae (81-1) to (81-6):
In an exemplary embodiment, the compound represented by the formula (8) is represented by any one of formulae (81-7) to (81-18) below.
In the formulae (81-7) to (81-18):
R801 to R808 not forming the divalent group represented by the formula (82) or (83) and not being the monovalent group represented by the formula (84), and R811 to R814 and R821 to R824 not being the monovalent group represented by the formula (84) are preferably 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 aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms.
The monovalent group represented by the formula (84) is preferably represented by a formula (85) or (86) below.
In the formula (85):
In the formula (86):
In the formula (87):
Specific examples of the compound represented by the formula (8) include compounds shown below as well as the compounds disclosed in WO 2014/104144.
The compound represented by the formula (9) will be described below.
In the formula (9):
In the formula (92):
At least one ring selected from the group consisting of A91 ring and A92 ring is bonded to * of a structure represented by the formula (92). In other words, the ring carbon atoms of the aromatic hydrocarbon ring or the ring atoms of the heterocycle of the A91 ring in an exemplary embodiment are bonded to * in a structure represented by the formula (92). Further, the ring carbon atoms of the aromatic hydrocarbon ring or the ring atoms of the heterocycle of the A92 ring in an exemplary embodiment are bonded to * in a structure represented by the formula (92).
In an exemplary embodiment, a group represented by a formula (93) below is bonded to one or both of the A91 ring and A92 ring.
In the formula (93):
In an exemplary embodiment, in addition to the A91 ring, the ring carbon atoms of the aromatic hydrocarbon ring or the ring atoms of the heterocycle of the A92 ring are bonded to * in a structure represented by the formula (92). In this case, the structures represented by the formula (92) may be mutually the same or different.
In an exemplary embodiment, R91 and R92 are each independently a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms.
In an exemplary embodiment, R91 and R92 are mutually bonded to form a fluorene structure.
In an exemplary embodiment, the rings A91 and A92 are each independently a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 50 ring carbon atoms, example of which is a substituted or unsubstituted benzene ring.
In an exemplary embodiment, the ring A93 is a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 50 ring carbon atoms, example of which is a substituted or unsubstituted benzene ring.
In an exemplary embodiment, X9 is an oxygen atom or a sulfur atom.
Specific examples of the compound represented by the formula (9) include compounds shown below.
The compound represented by the formula (10) will be described below.
In the formula (10):
In an exemplary embodiment, Ar1001 is a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms.
In an exemplary embodiment, Ax3 ring is a substituted or unsubstituted aromatic hydrocarbon ring having 6 to 50 ring carbon atoms, example of which is a substituted or unsubstituted benzene ring, a substituted or unsubstituted naphthalene ring, or a substituted or unsubstituted anthracene ring.
In an exemplary embodiment, R1003 and R1004 are each independently a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms.
In an exemplary embodiment, ax is 1.
Specific examples of the compound represented by the formula (10) include compounds shown below.
In an exemplary embodiment, the emitting layer contains, as the emitting compound, at least one compound selected from the group consisting of a compound represented by the formula (4), a compound represented by the formula (5), a compound represented by the formula (7), a compound represented by the formula (8), a compound represented by the formula (9), and a compound represented by a formula (63a) below.
In the formula (63a):
In an exemplary embodiment, the compound represented by the formula (4) is a compound represented by the formula (41-3), the formula (41-4), or the formula (41-5), the A1 ring in the formula (41-5) being a substituted or unsubstituted fused aromatic hydrocarbon ring having 10 to 50 ring carbon atoms or a substituted or unsubstituted fused heterocycle having 8 to 50 ring atoms.
In an exemplary embodiment, the substituted or unsubstituted fused aromatic hydrocarbon ring having 10 to 50 ring carbon atoms in the formulae (41-3), (41-4) and (41-5) is a substituted or unsubstituted naphthalene ring, a substituted or unsubstituted anthracene ring, or a substituted or unsubstituted fluorene ring; and the substituted or unsubstituted fused heterocycle having 8 to 50 ring atoms is a substituted or unsubstituted dibenzofuran ring, a substituted or unsubstituted carbazole ring, or a substituted or unsubstituted dibenzothiophene ring.
In an exemplary embodiment, the substituted or unsubstituted fused aromatic hydrocarbon ring having 10 to 50 ring carbon atoms in the formula (41-3), (41-4) or (41-5) is a substituted or unsubstituted naphthalene ring or a substituted or unsubstituted fluorene ring; and the substituted or unsubstituted fused heterocycle having 8 to 50 ring atoms is a substituted or unsubstituted dibenzofuran ring, a substituted or unsubstituted carbazole ring, or a substituted or unsubstituted dibenzothiophene ring.
In an exemplary embodiment, the compound represented by the formula (4) is selected from the group consisting of a compound represented by a formula (461) below, a compound represented by a formula (462) below, a compound represented by a formula (463) below, a compound represented by a formula (464) below, a compound represented by a formula (465) below, a compound represented by a formula (466) below, and a compound represented by a formula (467) below.
In the formulae (461) to (467):
In an exemplary embodiment, R421 to R427 and R440 to R448 are each independently a hydrogen atom, 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 an exemplary embodiment, R421 to R427 and R440 to R447 are each independently selected from the group consisting of a hydrogen atom, a substituted or unsubstituted aryl group having 6 to 18 ring carbon atoms, and a substituted or unsubstituted heterocyclic group having 5 to 18 ring atoms.
In an exemplary embodiment, the compound represented by the formula (41-3) is a compound represented by a formula (41-3-1) below.
In the formula (41-3-1), R423, R425, R426, R442, R444 and R445 each independently represent the same as R423, R425, R426, R442, R444 and R445 in the formula (41-3).
In an exemplary embodiment, the compound represented by the formula (41-3) is a compound represented by a formula (41-3-2) below.
In the formula (41-3-2), R421 to R427 and R440 to R448 each independently represent the same as R421 to R427 and R440 to R448 in the formula (41-3); and at least one of R421 to R427 or R440 to R446 is a group represented by —N(R906)(R907).
In an exemplary embodiment, two of R421 to R427 and R440 to R446 in the formula (41-3-2) are each a group represented by —N(R906)(R907).
In an exemplary embodiment, the compound represented by the formula (41-3-2) is a compound represented by a formula (41-3-3) below.
In the formula (41-3-3): R421 to R424, R440 to R443, R447, and R448 each independently represent the same as R421 to R424, R440 to R443, R447, and R448 in the formula (41-3); and RA, RB, RC, and RD are each independently a substituted or unsubstituted aryl group having 6 to 18 ring carbon atoms or a substituted or unsubstituted heterocyclic group having 5 to 18 ring atoms.
In an exemplary embodiment, the compound represented by the formula (41-3-3) is a compound represented by a formula (41-3-4) below.
In the formula (41-3-4), R447, R448, RA, RB, RC and RD each independently represent the same as R447, R448, RA, RB, RC and RD in the formula (41-3-3).
In an exemplary embodiment, RA, RB, RC, and RD are each independently a substituted or unsubstituted aryl group having 6 to 18 ring carbon atoms.
In an exemplary embodiment, RA, RB, RC, and RD are each independently a substituted or unsubstituted phenyl group.
In an exemplary embodiment, R447 and R448 are each a hydrogen atom.
In an exemplary embodiment, the substituent for “the substituted or unsubstituted” group in each of the formulae is 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(R901a)(R902a)(R903a), —O—(R904a), —S—(R905a), —N(R906a)(R907a), a halogen atom, a cyano group, a nitro group, an unsubstituted aryl group having 6 to 50 ring carbon atoms, or an unsubstituted heterocyclic group having 5 to 50 ring atoms;
In an exemplary embodiment, the substituent for “the substituted or unsubstituted” group in each of the above formulae is 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.
In an exemplary embodiment, the substituent for “the substituted or unsubstituted” group in each of the above formulae is an unsubstituted alkyl group having 1 to 18 carbon atoms, an unsubstituted aryl group having 6 to 18 ring carbon atoms, or an unsubstituted heterocyclic group having 5 to 18 ring atoms.
In the organic EL device according to the exemplary embodiment, the emitting compound is preferably not a pyrene compound having two substituted or unsubstituted amino groups.
In the organic EL device according to the exemplary embodiment, it is expectable that a relationship of T1(D)>T1(H1)>T1(H2) is satisfied by using the emitting compound other than a pyrene compound having two substituted or unsubstituted amino groups.
The organic EL device according to the exemplary embodiment may include at least one organic layer in addition to a single layer (first emitting layer) containing the first host material, the second host material, and the emitting compound as the emitting layer. Examples of the organic layer include at least one layer selected from the group consisting of a hole injecting layer, a hole transporting layer, an electron injecting layer, an electron transporting layer, a hole blocking layer, and an electron blocking layer.
In the organic EL device according to the exemplary embodiment containing the anode and the cathode, a single emitting layer (first emitting layer) containing the first host material, the second host material, and the emitting compound as the emitting layer is preferably provided between the anode and the cathode.
An organic EL device 1 includes a light-transmissive substrate 2, an anode 3, a cathode 4, and organic layers 10 provided between the anode 3 and the cathode 4. The organic layers 10 are a hole injecting layer 6, a hole transporting layer 7, an emitting layer 5, an electron transporting layer 8, and an electron injecting layer 9 that are layered on the anode 3 in this order. The organic EL device of the invention may have any arrangement without being limited to the arrangement of the organic EL device illustrated in
The arrangement of the organic EL device will be 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. Further, 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.
A material having a small work function such as elements belonging to Groups 1 and 2 in the periodic table of the elements, specifically, an alkali metal such as lithium (Li) and cesium (Cs), an alkaline earth metal such as magnesium (Mg), calcium (Ca) and strontium (Sr), alloys (e.g., MgAg and AlLi) including the alkali metal or the alkaline earth metal, a rare earth metal such as europium (Eu) and ytterbium (Yb), alloys including the rare earth metal are also 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 the material for the cathode include elements belonging to Groups 1 and 2 in the periodic table of the elements, specifically, an alkali metal such as lithium (Li) and cesium (Cs), an alkaline earth metal such as magnesium (Mg), calcium (Ca) and strontium (Sr), alloys (e.g., MgAg and AlLi) including the alkali metal or the alkaline earth metal, a rare earth metal such as europium (Eu) and ytterbium (Yb), and alloys including 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[2,3-f: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 organic EL device according to the exemplary embodiment also preferably includes the hole transporting layer provided between the anode and a single emitting layer (first emitting layer) containing the first host material, the second host material, and the emitting compound as the emitting layer.
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 cm2Ns 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).
The organic EL device according to the exemplary embodiment also preferably includes the electron transporting layer provided between the cathode and a single emitting layer (first emitting layer) containing the first host material, the second host material, and the emitting compound as 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 exemplary embodiment, a benzimidazole compound is preferably usable. The above-described substances mostly have an electron mobility of 10−6 cm2Ns or more. It should be noted that any other substance 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.
In the organic EL device according to the exemplary embodiment, a single emitting layer (first emitting layer) containing the first host material, the second host material, and the emitting compound as the emitting layer can be formed, for instance, by co-deposition using a plurality of types of compounds, by vapor-deposition using a mixture of a plurality of types of compounds prepared in advance, or by coating using a mixture of a plurality of types of compounds prepared in advance. The mixture prepared by mixing a plurality of types of compounds in advance may be a powder. The mixture prepared by mixing a plurality of types of compounds in advance may be a solution.
A method for forming each layer of the organic EL device in the 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.
The film thickness of each of the organic layers of the organic EL device according to the exemplary embodiment is not limited unless otherwise specified in the above. In general, the thickness preferably ranges from several nanometers to 1 μm because an excessively small film thickness is likely to cause defects (e.g. pin holes) and an excessively large thickness leads to the necessity of applying high voltage and consequent reduction in efficiency.
An electronic device according to a fourth exemplary embodiment is installed with any one of the organic EL 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 by 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 of the organic EL device may consist of a single layer containing the first host material, the second host material, and the emitting compound, or alternatively, the emitting layer is not limited to one layer but may be a laminate of more than one layers. In a case where the organic EL device includes more than one layers, it is only required that at least one layer is a single layer containing the first host material, the second host material, and the emitting compound. For instance, the organic EL device may include a first emitting layer (i.e., a single layer containing the first host material, the second host material, and the emitting compound) and another emitting layer different from the first emitting layer (e.g., a second emitting layer). The another emitting layer different from the first emitting layer may be a fluorescent emitting layer(s) or a phosphorescent emitting layer(s) with use of emission caused by electron transfer from the triplet state directly to the ground state.
In a case where the organic EL device includes a plurality of emitting layers, these emitting layers may be mutually adjacently provided, or may form a so-called tandem organic EL device, in which a plurality of emitting units are layered via an intermediate layer.
For instance, a blocking layer may be provided adjacent to at least one of a side of the emitting layer close to the anode or a side of the emitting layer close to the cathode. The blocking layer is preferably provided in contact with the emitting layer to block at least any of holes, electrons, 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 is preferably interposed between the emitting layer and the electron transporting layer.
When the blocking layer is provided in contact with the side of the emitting layer close to the anode, the blocking layer permits transport of holes and blocks electrons from reaching a layer provided closer to the anode (e.g., the hole transporting layer) beyond the blocking layer. When the organic EL device includes the hole transporting layer, the blocking layer is preferably interposed between the emitting layer and the hole 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 hole transporting layer) closer to the electrode(s) beyond the blocking layer.
The emitting layer is preferably bonded 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.
The invention will be described in more detail below with reference to Examples. The scope of the invention is by no means limited to Examples.
Structures of compounds used for forming the emitting layer of organic EL devices in Examples 1 to 3 are shown below.
Structures of other compounds used for producing organic EL devices in Examples 1 to 3 and Comparative 1 are shown below.
The organic EL devices were produced and evaluated as follows.
A glass substrate (size: 25 mm×75 mm×1.1 mm thick, produced 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. The film thickness of the ITO transparent electrode was 130 nm.
After the glass substrate having the transparent electrode line was cleaned, the glass substrate was mounted on a substrate holder of a vacuum deposition apparatus. Firstly, the compound HT1 and the compound HA1 were co-deposited on a surface of the glass substrate where the transparent electrode line was provided in a manner to cover the transparent electrode, thereby forming a 10-nm-thick hole injecting layer (HI). The ratios of the compound HT1 and the compound HA1 in the hole injecting layer were 97 mass % and 3 mass %, respectively.
Subsequent to formation of the hole injecting layer, the compound HT1 was vapor-deposited to form a 85-nm-thick hole transporting layer.
Subsequent to formation of the hole transporting layer, a compound HT2 was vapor-deposited to form a 5-nm-thick electron blocking layer.
A compound BH1-1 (first host material), a compound BH2 (second host material), and a compound BD1 (emitting compound) were co-deposited on the electron blocking layer to form a 20-nm-thick emitting layer. The ratios of the compound BH1-1, the compound BH2, and the compound BD1 in the emitting layer were 10 mass %, 89 mass %, and 1 mass %, respectively. The ratios (contents) of the first host material, the second host material, the emitting compound in the emitting layer are shown in Table 1.
A compound ET1 was vapor-deposited on the emitting layer to form a 5-nm-thick hole blocking layer.
A compound ET2 and a compound Liq were co-deposited on the hole blocking layer to form a 25-nm-thick electron transporting layer. The ratios of the compound ET2 and the compound Liq in the electron transporting layer were both 50 mass %.
The compound Liq was vapor-deposited on the electron transporting layer to form a 1-nm-thick electron injecting layer.
Metal Al was vapor-deposited on the electron injecting layer to form an 80-nm-thick cathode.
A device arrangement of the organic EL device in Example 1 is roughly shown as follows.
ITO(130)/HT1:HA1(10,97%:3%)/HT1(85)/HT2(5)/BH1-1:BH2:BD1(20,10%:89%:1%)/ET1(5)/ET2:Liq(25,50%:50%)/Liq(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 HT1 and the compound HA1 in the hole injecting layer. The numerals (10%: 89%:1%) represented by percentage in the same parentheses indicate a ratio (mass %) between the first host material (compound BH1-1), the second host material (compound BH2), and the emitting compound (compound BD1) in the emitting layer. The numerals (50%:50%) represented by percentage in the same parentheses indicate a ratio (mass %) between the compound ET2 and the compound Liq in the electron transporting layer.
An organic EL device in Example 2 was produced in the same manner as in Example 1 except that the ratios of the compound BH1-1, the compound BH2, and the compound BD1 in the emitting layer were changed to 30 mass %, 69 mass %, and 1 mass %, respectively, to form the emitting layer.
An organic EL device in Example 3 was produced in the same manner as in Example 1 except that the compound BH1-1 in the emitting layer was replaced by the compound BH1-2 and the ratios of the compound BH1-2, the compound BH2, and the compound BD1 in the emitting layer were changed to 15 mass %, 84 mass %, and 1 mass %, respectively, to form the emitting layer.
An organic EL device in Comparative 1 was produced in the same manner as in Example 1 except that the compound BH2 (second host material) and the compound BD1 (emitting compound) were co-deposited to form a 20-nm thick emitting layer and the ratios of the compound BH2 and the compound BD1 in the emitting layer were changed to 99 mass % and 1 mass %, respectively.
The organic EL devices produced were evaluated as follows. Table 1 shows the evaluation results. Table 1 also shows the triplet energy T1 and the singlet energy S1 of each of the first host material, the second host material, the emitting compound used in the emitting layer in each Example.
Voltage was applied to the produced organic EL device such that a current density was 50 mA/cm2, where a time (LT95 (unit: hr)) elapsed before a luminance intensity was reduced to 95% of the initial luminance intensity was measured as a lifetime. The luminance intensity was measured with a spectroradiometer CS-2000 (manufactured by Konica Minolta, Inc.). LT95 (relative value) (unit: %) was calculated based on the measurement value of LT95 in each Example according to a numerical formula (Numerical Formula 1X) below.
The organic EL devices of Examples 1 to 3 each had a longer lifetime than that of the organic EL device of Comparative 1 because of containing, in the emitting layer (single layer), the first host material, the second host material, and the emitting compound that satisfy at least one of the relationship of the numerical formula (Numerical Formula 1) or the relationship of the numerical formula (Numerical Formula 2).
A measurement target compound was dissolved in EPA (diethylether:isopentane:ethanol=5:5:2 in volume ratio) at a concentration of 10 μmol/L, and the obtained solution was put in a quartz cell to provide a measurement sample. A phosphorescence spectrum (ordinate axis: phosphorescent luminous intensity, abscissa axis: wavelength) of the measurement sample was measured at a low temperature (77K). A tangent was drawn to the rise of the phosphorescence spectrum close to the short-wavelength region. An energy amount was calculated by a conversion equation (F1) below on a basis of a wavelength value λedge [nm] at an intersection of the tangent and the abscissa axis. The calculated energy amount was defined as triplet energy T1. It should be noted that the triplet energy T1 may have an error of about plus or minus 0.02 eV depending on measurement conditions.
T
1 [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 was used.
A toluene solution of a measurement target compound at a concentration of 10 μmol/L was prepared and put in a quartz cell. An absorption spectrum (ordinate axis: absorption intensity, abscissa axis: wavelength) of the thus-obtained sample was measured at a 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 singlet energy.
S
1 [eV]=1239.85/Δedge Conversion Equation (F2):
A spectrophotometer (U3310 manufactured by Hitachi, Ltd.) was used for measuring absorption spectrum.
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.
Measurement of Maximum Fluorescence Peak Wavelength (FL-peak) A measurement target compound was dissolved in toluene at a concentration of 4.9×10−6 mol/L to prepare a toluene solution. Using a fluorescence spectrometer (spectrophotofluorometer F-7000 produced by Hitachi High-Tech Science Corporation), the toluene solution of the measurement target compound was excited at 390 nm, where a maximum fluorescence peak wavelength A (unit: nm) was measured.
The maximum fluorescence peak wavelength A of the compound BD1 was 455 nm.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-080974 | May 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/019951 | 5/11/2022 | WO |
