Patent Application
20240368103
The entire disclosure of Japanese Patent Application No. 2022-203858, filed Dec. 21, 2022, is expressly incorporated by reference herein.
The present invention relates to a compound, an organic-electroluminescence-device material, an organic electroluminescence device, and an electronic device.
When voltage is applied to an organic electroluminescence device (hereinafter, occasionally referred to as “organic EL device”), holes are injected from an anode and electrons are injected from a cathode into an emitting layer. The injected electrons and holes are recombined in the emitting layer to form excitons. Specifically, according to the electron spin statistics theory, singlet excitons and triplet excitons are generated at a ratio of 25%:75%.
A fluorescent organic EL device using light emission from singlet excitons has been applied to a full-color display such as a mobile phone and a television, but an internal quantum efficiency is said to be at a limit of 25%. Studies have thus been made to improve performance of the organic EL device.
For instance, Literature 1 (Korean Patent Application Publication No. 10-2021-0088818 A), Literature 2 (U.S. Patent Application Publication No. 2019/0115538 A1), and Literature 3 (U.S. Patent Application Publication No. 2021/0320256 A1) disclose, as a compound that may be used for an organic electroluminescence device, a compound in which a fused ring including an oxygen atom is bonded to an anthracene ring.
A further improvement in performance of the organic EL device has been demanded for an improvement in performance of an electronic device such as a display. The performance of the organic EL device is evaluable in terms of, for instance, luminance, emission wavelength, full width at half maximum, chromaticity, luminous efficiency, drive voltage, and lifetime.
An object of the invention is to provide a compound capable of improving performance of an organic electroluminescence device when used as a host material. Another object of the invention is to provide a novel compound usable in an organic electroluminescence device. Still another object of the invention is to provide an organic-electroluminescence-device material containing the compound. A further object of the invention is to provide an organic electroluminescence device containing a compound capable of improving performance, and an electronic device installed with the organic electroluminescence device.
According to an aspect of the invention, a compound represented by a formula (1) below is provided.
In the formula (1):
In the formulae (A) to (F):
According to an aspect of the invention, there is provided an organic-electroluminescence-device material containing a compound according to an aspect of the invention.
According to an aspect of the invention, there is provided an organic electroluminescence device including an anode, a cathode, and an emitting layer provided between the anode and the cathode, in which the emitting layer contains a first compound that is a compound according to an aspect of the invention.
According to an aspect of the invention, there is provided an electronic device provided with an organic electroluminescence device according to an aspect of the invention.
According to an aspect of the invention, there can be provided a compound capable of improving performance of an organic electroluminescence device when used as a host material. According to an aspect of the invention, there can be provided a novel compound usable in an organic electroluminescence device. According to an aspect of the invention, there can be provided an organic-electroluminescence-device material containing the compound. According to an aspect of the invention, there can be provided an organic electroluminescence device containing a compound capable of improving performance, and an electronic device installed with the organic electroluminescence device.
Herein, a hydrogen atom includes isotope having different numbers of neutrons, specifically, protium, deuterium and tritium.
In chemical formulae herein, it is assumed that a hydrogen atom (i.e. protium, deuterium and tritium) is bonded to each of bondable positions that are not annexed with signs “R” or the like or “D” representing a deuterium.
Herein, the ring carbon atoms refer to the number of carbon atoms among atoms forming a ring of a compound (e.g., a monocyclic compound, fused-ring compound, cross-linking compound, carbon ring compound, and heterocyclic compound) in which the atoms are bonded to each other to form the ring. When the ring is substituted by a substituent(s), carbon atom(s) contained in the substituent(s) is not counted in the ring carbon atoms. Unless otherwise specified, the same applies to the “ring carbon atoms” described later. For instance, a benzene ring has 6 ring carbon atoms, a naphthalene ring has 10 ring carbon atoms, a pyridine ring has 5 ring carbon atoms, and a furan ring has 4 ring carbon atoms. Further, for instance, 9,9-diphenylfluorenyl group has 13 ring carbon atoms and 9,9′-spirobifluorenyl group has 25 ring carbon atoms.
When a benzene ring is substituted by a substituent in a form of, for instance, an alkyl group, the number of carbon atoms of the alkyl group is not counted in the number of the ring carbon atoms of the benzene ring. Accordingly, the benzene ring substituted by an alkyl group has 6 ring carbon atoms. When a naphthalene ring is substituted by a substituent in a form of, for instance, an alkyl group, the number of carbon atoms of the alkyl group is not counted in the number of the ring carbon atoms of the naphthalene ring. Accordingly, the naphthalene ring substituted by an alkyl group has 10 ring carbon atoms.
Herein, the ring atoms refer to the number of atoms forming a ring of a compound (e.g., a monocyclic compound, fused-ring compound, cross-linking compound, carbon ring compound, and heterocyclic compound) in which the atoms are bonded to each other to form the ring (e.g., monocyclic ring, fused ring, and ring assembly). Atom(s) not forming the ring (e.g., hydrogen atom(s) for saturating the valence of the atom which forms the ring) and atom(s) in a substituent by which the ring is substituted are not counted as the ring atoms. Unless otherwise specified, the same applies to the “ring atoms” described later. For instance, a pyridine ring has 6 ring atoms, a quinazoline ring has 10 ring atoms, and a furan ring has 5 ring atoms. For instance, the number of hydrogen atom(s) bonded to a pyridine ring or the number of atoms forming a substituent is not counted as the pyridine ring atoms. Accordingly, a pyridine ring bonded to a hydrogen atom(s) or a substituent(s) has 6 ring atoms. For instance, the hydrogen atom(s) bonded to carbon atom(s) of a quinazoline ring or the atoms forming a substituent are not counted as the quinazoline ring atoms. Accordingly, a quinazoline ring bonded to hydrogen atom(s) or a substituent(s) has 10 ring atoms.
Herein, “XX to YY carbon atoms” in the description of “substituted or unsubstituted ZZ group having XX to YY carbon atoms” represent carbon atoms of an unsubstituted ZZ group and do not include carbon atoms of a substituent(s) of the substituted ZZ group. Herein, “YY” is larger than “XX,” “XX” representing an integer of 1 or more and “YY” representing an integer of 2 or more.
Herein, “XX to YY atoms” in the description of “substituted or unsubstituted ZZ group having XX to YY atoms” represent atoms of an unsubstituted ZZ group and does not include atoms of a substituent(s) of the substituted ZZ group. Herein, “YY” is larger than “XX,” “XX” representing an integer of 1 or more and “YY” representing an integer of 2 or more.
Herein, an unsubstituted ZZ group refers to an “unsubstituted ZZ group” in a “substituted or unsubstituted ZZ group,” and a substituted ZZ group refers to a “substituted ZZ group” in a “substituted or unsubstituted ZZ group.”
Herein, the term “unsubstituted” used in a “substituted or unsubstituted ZZ group” means that a hydrogen atom(s) in the ZZ group is not substituted with a substituent(s). The hydrogen atom(s) in the “unsubstituted ZZ group” is protium, deuterium, or tritium.
Herein, the term “substituted” used in a “substituted or unsubstituted ZZ group” means that at least one hydrogen atom in the ZZ group is substituted with a substituent. Similarly, the term “substituted” used in a “BB group substituted by AA group” means that at least one hydrogen atom in the BB group is substituted with the AA group.
Substituent mentioned herein will be described below.
An “unsubstituted aryl group” mentioned herein has, unless otherwise specified herein, 6 to 50, preferably 6 to 30, more preferably 6 to 18 ring carbon atoms.
An “unsubstituted heterocyclic group” mentioned herein has, unless otherwise specified herein, 5 to 50, preferably 5 to 30, more preferably 5 to 18 ring atoms.
An “unsubstituted alkyl group” mentioned herein has, unless otherwise specified herein, 1 to 50, preferably 1 to 20, more preferably 1 to 6 carbon atoms.
An “unsubstituted alkenyl group” mentioned herein has, unless otherwise specified herein, 2 to 50, preferably 2 to 20, more preferably 2 to 6 carbon atoms.
An “unsubstituted alkynyl group” mentioned herein has, unless otherwise specified herein, 2 to 50, preferably 2 to 20, more preferably 2 to 6 carbon atoms.
An “unsubstituted cycloalkyl group” mentioned herein has, unless otherwise specified herein, 3 to 50, preferably 3 to 20, more preferably 3 to 6 ring carbon atoms.
An “unsubstituted arylene group” mentioned herein has, unless otherwise specified herein, 6 to 50, preferably 6 to 30, more preferably 6 to 18 ring carbon atoms.
An “unsubstituted divalent heterocyclic group” mentioned herein has, unless otherwise specified herein, 5 to 50, preferably 5 to 30, more preferably 5 to 18 ring atoms.
An “unsubstituted alkylene group” mentioned herein has, unless otherwise specified herein, 1 to 50, preferably 1 to 20, more preferably 1 to 6 carbon atoms.
Specific examples (specific example group G1) of the “substituted or unsubstituted aryl group” mentioned herein include unsubstituted aryl groups (specific example group G1A) below and substituted aryl groups (specific example group G1B). (Herein, an unsubstituted aryl group refers to an “unsubstituted aryl group” in a “substituted or unsubstituted aryl group”, and a substituted aryl group refers to a “substituted aryl group” in a “substituted or unsubstituted aryl group.”) A simply termed “aryl group” herein includes both of an “unsubstituted aryl group” and a “substituted aryl group”.
The “substituted aryl group” refers to a group derived by substituting at least one hydrogen atom in an “unsubstituted aryl group” with a substituent. Examples of the “substituted aryl group” include a group derived by substituting at least one hydrogen atom in the “unsubstituted aryl group” in the specific example group G1A below with a substituent, and examples of the substituted aryl group in the specific example group G1B below. It should be noted that the examples of the “unsubstituted aryl group” and the “substituted aryl group” mentioned herein are merely exemplary, and the “substituted aryl group” mentioned herein includes a group derived by further substituting a hydrogen atom bonded to a carbon atom of a skeleton of a “substituted aryl group” in the specific example group G1B below, and a group derived by further substituting a hydrogen atom of a substituent of the “substituted aryl group” in the specific example group G1B below.
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.
Unsubstituted Heterocyclic Groups Including Nitrogen Atom (Specific Example Group G2A1):
Unsubstituted Heterocyclic Groups Including Oxygen Atom (Specific Example Group G2A2):
Unsubstituted Heterocyclic Groups Including Sulfur Atom (Specific Example Group G2A3):
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.
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.
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.
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.
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.
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 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. The plurality of G3 in —Si(G3)(G3)(G3) are mutually the same or different. Each of the alkyl groups in the “trialkylsilyl group” has, unless otherwise specified herein, 1 to 50, preferably 1 to 20, more preferably 1 to 6 carbon atoms.
Specific examples of a “substituted or unsubstituted aralkyl group” mentioned herein include a group represented by -(G3)-(G1), G3 being the “substituted or unsubstituted alkyl group” in the specific example group G3, G1 being the “substituted or unsubstituted aryl group” in the specific example group G1. Accordingly, the “aralkyl group” is a group derived by substituting a hydrogen atom of the “alkyl group” with a substituent in a form of the “aryl group,” which is an example of the “substituted alkyl group.” An “unsubstituted aralkyl group,” which is an “unsubstituted alkyl group” substituted by an “unsubstituted aryl group,” has, unless otherwise specified herein, 7 to 50 carbon atoms, preferably 7 to 30 carbon atoms, more preferably 7 to 18 carbon atoms.
Specific examples of the “substituted or unsubstituted aralkyl group” include a benzyl group, 1-phenylethyl group, 2-phenylethyl group, 1-phenylisopropyl group, 2-phenylisopropyl group, phenyl-t-butyl group, α-naphthylmethyl group, 1-α-naphthylethyl group, 2-α-naphthylethyl group, 1-α-naphthylisopropyl group, 2-α-naphthylisopropyl group, β-naphthylmethyl group, 1-β-naphthylethyl group, 2-β-naphthylethyl group, 1-β-naphthylisopropyl group, and 2-β-naphthylisopropyl group.
Preferable examples of the substituted or unsubstituted aryl group mentioned herein include, unless otherwise specified herein, a phenyl group, p-biphenyl group, m-biphenyl group, o-biphenyl group, p-terphenyl-4-yl group, p-terphenyl-3-yl group, p-terphenyl-2-yl group, m-terphenyl-4-yl group, m-terphenyl-3-yl group, m-terphenyl-2-yl group, o-terphenyl-4-yl group, o-terphenyl-3-yl group, o-terphenyl-2-yl group, 1-naphthyl group, 2-naphthyl group, anthryl group, phenanthryl group, pyrenyl group, chrysenyl group, triphenylenyl group, fluorenyl group, 9,9′-spirobifluorenyl group, 9,9-dimethylfluorenyl group, and 9,9-diphenylfluorenyl group.
Preferable examples of the substituted or unsubstituted heterocyclic group mentioned herein include, unless otherwise specified herein, a pyridyl group, pyrimidinyl group, triazinyl group, quinolyl group, isoquinolyl group, quinazolinyl group, benzimidazolyl group, phenanthrolinyl group, carbazolyl group (1-carbazolyl group, 2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group, or 9-carbazolyl group), benzocarbazolyl group, azacarbazolyl group, diazacarbazolyl group, dibenzofuranyl group, naphthobenzofuranyl group, azadibenzofuranyl group, diazadibenzofuranyl group, dibenzothiophenyl group, naphthobenzothiophenyl (9-group, azadibenzothiophenyl group, diazadibenzothiophenyl group, (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.
5 In the formulae (TEMP-Cz1) to (TEMP-Cz9), * represents a bonding position. The dibenzofuranyl group and dibenzothiophenyl group mentioned herein are, unless otherwise specified herein, each specifically represented by one of formulae below.
In the formulae (TEMP-34) to (TEMP-41), * represents a bonding position.
Preferable examples of the substituted or unsubstituted alkyl group mentioned herein include, unless otherwise specified herein, a methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, and t-butyl group.
The “substituted or unsubstituted arylene group” mentioned herein is, unless otherwise specified herein, a divalent group derived by removing one hydrogen atom on an aryl ring of the “substituted or unsubstituted aryl group.” Specific examples of the “substituted or unsubstituted arylene group” (specific example group G12) include a divalent group derived by removing one hydrogen atom on an aryl ring of the “substituted or unsubstituted aryl group” in the specific example group G1.
The “substituted or unsubstituted divalent heterocyclic group” mentioned herein is, unless otherwise specified herein, a divalent group derived by removing one hydrogen atom on a heterocycle of the “substituted or unsubstituted heterocyclic group.” Specific examples of the “substituted or unsubstituted divalent heterocyclic group” (specific example group G13) include a divalent group derived by removing one hydrogen atom on a heterocyclic ring of the “substituted or unsubstituted heterocyclic group” in the specific example group G2.
The “substituted or unsubstituted alkylene group” mentioned herein is, unless otherwise specified herein, a divalent group derived by removing one hydrogen atom on an alkyl chain of the “substituted or unsubstituted alkyl group.” Specific examples of the “substituted or unsubstituted alkylene group” (specific example group G14) include a divalent group derived by removing one hydrogen atom on an alkyl chain of the “substituted or unsubstituted alkyl group” in the specific example group G3.
The substituted or unsubstituted arylene group mentioned herein is, unless otherwise specified herein, preferably any one of groups represented by formulae (TEMP-42) to (TEMP-68) below.
In the formulae (TEMP-42) to (TEMP-52), Q1 to Q10 are each independently a hydrogen atom or a substituent.
In the formulae (TEMP-42) to (TEMP-52), * represents a bonding position.
In the formulae (TEMP-53) to (TEMP-62), Q1 to Q10 are each independently a hydrogen atom or a substituent.
In the formulae, Q9 and Q10 may be mutually bonded through a single bond to form a ring.
In the formulae (TEMP-53) to (TEMP-62), * represents a bonding position.
In the formulae (TEMP-63) to (TEMP-68), Q1 to Q8 are each independently a hydrogen atom or a substituent.
In the formulae (TEMP-63) to (TEMP-68), * represents a bonding position.
The substituted or unsubstituted divalent heterocyclic group mentioned herein is, unless otherwise specified herein, preferably a group represented by any one of formulae (TEMP-69) to (TEMP-102) below.
In the formulae (TEMP-69) to (TEMP-82), Q1 to Q9 are each independently a hydrogen atom or a substituent.
In the formulae (TEMP-83) to (TEMP-102), Q1 to Q8 are each independently a hydrogen atom or a substituent.
The substituent mentioned herein has been described above.
Instances where “at least one combination of adjacent two or more (of . . . ) are mutually bonded to form a substituted or unsubstituted monocyclic ring, mutually bonded to form a substituted or unsubstituted fused ring, or not mutually bonded” mentioned herein refer to instances where “at least one combination of adjacent two or more (of . . . ) are mutually bonded to form a substituted or unsubstituted monocyclic ring, “at least one combination of adjacent two or more (of . . . ) are mutually bonded to form a substituted or unsubstituted fused ring,” and “at least one combination of adjacent two or more (of . . . ) are not mutually bonded.”
Instances where “at least one combination of adjacent two or more (of . . . ) are mutually bonded to form a substituted or unsubstituted monocyclic ring” and “at least one combination of adjacent two or more (of . . . ) are mutually bonded to form a substituted or unsubstituted fused ring” mentioned herein (these instances will be sometimes collectively referred to as an instance of “bonded to form a ring” hereinafter) will be described below. An anthracene compound having a basic skeleton in a form of an anthracene ring and represented by a formula (TEMP-103) below will be used as an example for the description.
For instance, when “at least one combination of adjacent two or more of R921 to R930 are mutually bonded to form a ring,” the combination of adjacent ones of R921 to R930 (i.e. the combination at issue) is a combination of R921 and R922, a combination of R922 and R923, a combination of R923 and R924, a combination of R924 and R930, a combination of R930 and R925, a combination of R925 and R926, a combination of R926 and R927, a combination of R927 and R928, a combination of R928 and R929, or a combination of R929 and R921.
The term “at least one combination” means that two or more of the above combinations of adjacent two or more of R921 to R930 may simultaneously form rings. For instance, when R921 and R922 are mutually bonded to form a ring QA and R925 and R926 are simultaneously mutually bonded to form a ring QB, the anthracene compound represented by the formula (TEMP-103) is represented by a formula (TEMP-104) below.
The instance where the “combination of adjacent two or more” form a ring means not only an instance where the “two” adjacent components are bonded but also an instance where adjacent “three or more” are bonded. For instance, R921 and R922 are mutually bonded to form a ring QA and R922 and R923 are mutually bonded to form a ring QC, and mutually adjacent three components (R921, R922 and R923) are mutually bonded to form a ring fused to the anthracene basic skeleton. In this case, the anthracene compound represented by the formula (TEMP-103) is represented by a formula (TEMP-105) below. In the formula (TEMP-105) below, the ring QA and the ring QC share R922.
The formed “monocyclic ring” or “fused ring” may be, in terms of the formed ring in itself, a saturated ring or an unsaturated ring. When the “combination of adjacent two” form a “monocyclic ring” or a “fused ring,” the “monocyclic ring” or “fused ring” may be a saturated ring or an unsaturated ring. For instance, the ring QA and the ring QB formed in the formula (TEMP-104) are each independently a “monocyclic ring” or a “fused ring.” Further, the ring QA and the ring QC formed in the formula (TEMP-105) are each a “fused ring.” The ring QA and the ring QC in the formula (TEMP-105) are fused to form a fused ring. When the ring QA in the formula (TEMP-104) is a benzene ring, the ring QA is a monocyclic ring. When the ring QA in the formula (TEMP-104) is a naphthalene ring, the ring QA is a fused ring.
The “unsaturated ring” represents an aromatic hydrocarbon ring or an aromatic heterocycle. The “saturated ring” represents an aliphatic hydrocarbon ring or a non-aromatic heterocycle.
Specific examples of the aromatic hydrocarbon ring include a ring formed by terminating a bond of a group in the specific example of the specific example group G1 with a hydrogen atom.
Specific examples of the aromatic heterocycle include a ring formed by terminating a bond of an aromatic heterocyclic group in the specific example of the specific example group G2 with a hydrogen atom.
Specific examples of the aliphatic hydrocarbon ring include a ring formed by terminating a bond of a group in the specific example of the specific example group G6 with a hydrogen atom.
The phrase “to form a ring” herein means that a ring is formed only by a plurality of atoms of a basic skeleton, or by a combination of a plurality of atoms of the basic skeleton and one or more optional atoms. For instance, the ring QA formed by mutually bonding R921 and R922 shown in the formula (TEMP-104) is a ring formed by a carbon atom of the anthracene skeleton bonded to R921, a carbon atom of the anthracene skeleton bonded to R922, and one or more optional atoms. Specifically, when the ring QA is a monocyclic unsaturated ring formed by R921 and R922, the ring formed by a carbon atom of the anthracene skeleton bonded to R921, a carbon atom of the anthracene skeleton bonded to R922, and four carbon atoms is a benzene ring.
The “optional atom” is, unless otherwise specified herein, preferably at least one atom selected from the group consisting of a carbon atom, nitrogen atom, oxygen atom, and sulfur atom. A bond of the optional atom (e.g. a carbon atom and a nitrogen atom) not forming a ring may be terminated by a hydrogen atom or the like or may be substituted by an “optional substituent” described later. When the ring includes an optional element other than carbon atom, the resultant ring is a heterocycle.
The number of “one or more optional atoms” forming the monocyclic ring or fused ring is, unless otherwise specified herein, preferably in a range from 2 to 15, more preferably in a range from 3 to 12, further preferably in a range from 3 to 5.
Unless otherwise specified herein, the ring, which may be a “monocyclic ring” or “fused ring,” is preferably a “monocyclic ring.”
Unless otherwise specified herein, the ring, which may be a “saturated ring” or “unsaturated ring,” is preferably an “unsaturated ring.”
Unless otherwise specified herein, the “monocyclic ring” is preferably a benzene ring.
Unless otherwise specified herein, the “unsaturated ring” is preferably a benzene ring.
When “at least one combination of adjacent two or more” (of . . . ) are “mutually bonded to form a substituted or unsubstituted monocyclic ring” or “mutually bonded to form a substituted or unsubstituted fused ring,” unless otherwise specified herein, at least one combination of adjacent two or more of components are preferably mutually bonded to form a substituted or unsubstituted “unsaturated ring” formed of a plurality of atoms of the basic skeleton, and 1 to 15 atoms of at least one element selected from the group consisting of carbon, nitrogen, oxygen and sulfur.
When the “monocyclic ring” or the “fused ring” has a substituent, the substituent is the substituent described in later-described “optional substituent.” When the “monocyclic ring” or the “fused ring” has a substituent, specific examples of the substituent are the substituents described in the above under the subtitle “Substituent Mentioned Herein.”
When the “saturated ring” or the “unsaturated ring” has a substituent, the substituent is the substituent described in later-described “optional substituent.”
When the “monocyclic ring” or the “fused ring” has a substituent, specific examples of the substituent are the substituents described in the above under the subtitle “Substituent Mentioned Herein.”
The above is the description for the instances where “at least one combination of adjacent two or more (of . . . ) are mutually bonded to form a substituted or unsubstituted monocyclic ring” and “at least one combination of adjacent two or more (of . . . ) are mutually bonded to form a substituted or unsubstituted fused ring” mentioned herein (sometimes referred to as an instance of “bonded to form a ring”).
In an exemplary embodiment herein, the substituent for the substituted or unsubstituted group (hereinafter sometimes referred to as an “optional substituent”), is for instance, a group selected from the group consisting of an unsubstituted alkyl group having 1 to 50 carbon atoms, an unsubstituted alkenyl group having 2 to 50 carbon atoms, an unsubstituted alkynyl group having 2 to 50 carbon atoms, an unsubstituted cycloalkyl group having 3 to 50 ring carbon atoms, —Si(R901)(R902)(R903), —O—(R904), —S—(R905), —N(R906)(R907), a halogen atom, a cyano group, a nitro group, an unsubstituted aryl group having 6 to 50 ring carbon atoms, and an unsubstituted heterocyclic group having 5 to 50 ring atoms;
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 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 18 carbon atoms, an aryl group having 6 to 18 ring carbon atoms, and a heterocyclic group having 5 to 18 ring atoms.
Specific examples of the above optional substituent are the same as the specific examples of the substituent described in the above under the subtitle “Substituent Mentioned Herein.”
Unless otherwise specified herein, adjacent ones of the optional substituents may form a “saturated ring” or an “unsaturated ring,” preferably a substituted or unsubstituted saturated five-membered ring, a substituted or unsubstituted saturated six-membered ring, a substituted or unsubstituted unsaturated five-membered ring, or a substituted or unsubstituted unsaturated six-membered ring, more preferably a benzene ring.
Unless otherwise specified herein, the optional substituent may further include a substituent. Examples of the substituent for the optional substituent are the same as the examples of the optional substituent.
Herein, numerical ranges represented by “AA to BB” represent a range whose lower limit is the value (AA) recited before “to” and whose upper limit is the value (BB) recited after “to.”
A compound according to the exemplary embodiment is a compound represented by a formula (1) below.
In the formula (1):
In the formulae (A) to (F):
The compound according to the exemplary embodiment when used as a host material improves the performance of the organic EL device.
An example of the compound according to the exemplary embodiment, when used as a host material, improves at least one of luminance, emission wavelength, full width at half maximum, chromaticity, luminous efficiency, drive voltage, or lifetime of the organic EL device.
According to an example of the exemplary embodiment, there can be provided a novel compound usable in the organic EL device.
In the compound according to the exemplary embodiment, L1 is preferably a single bond or a substituted or unsubstituted arylene group having 6 to 18 ring carbon atoms.
In the compound according to the exemplary embodiment, L1 is more preferably a single bond, a substituted or unsubstituted phenylene group, or a substituted or unsubstituted naphthylene group.
In the compound according to the exemplary embodiment, the compound represented by the formula (1) is preferably represented by a formula (11), (12), or (13) below.
In the formula (11), Ar100, R101 to R108, and HAr1 each independently represent the same as Ar100, R101 to R108, and HAr1 in the formula (1).
In the formulae (12) and (13):
In the formulae (12) and (13), it is preferable that none of a combination(s) of adjacent two or more of R100 are mutually bonded.
In the formulae (12) and (13), each independently, R100 are preferably a hydrogen atom, 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, more preferably a hydrogen atom or an unsubstituted aryl group having 6 to 18 ring carbon atoms, and still more preferably a hydrogen atom, an unsubstituted phenyl group, or an unsubstituted naphthyl group.
In the formulae (12) and (13), R100 is also preferably a hydrogen atom.
In the compound according to the exemplary embodiment, HAr1 is preferably a group represented by the formula (A) or (B).
In the compound according to the exemplary embodiment, HAr1 is also preferably a group represented by one of the formulae (C), (D), (E) and (F).
In the compound according to the exemplary embodiment, each independently, R101 to R108 are preferably a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 18 carbon atoms, 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, more preferably a hydrogen atom, 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, and still more preferably a hydrogen atom or an unsubstituted aryl group having 6 to 18 ring carbon atoms.
In the compound according to the exemplary embodiment, each independently, R101 to R108 are preferably a hydrogen atom, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted naphthyl group, and more preferably a hydrogen atom, an unsubstituted phenyl group, or an unsubstituted naphthyl group.
In the compound according to the exemplary embodiment, R101 to R108 are also preferably a hydrogen atom.
In the compound according to the exemplary embodiment, Ar100 is preferably a substituted or unsubstituted aryl group having 6 to 18 ring carbon atoms, and more preferably an unsubstituted aryl group having 6 to 18 ring carbon atoms.
In the compound according to the exemplary embodiment, Ar100 is preferably a substituted or unsubstituted phenyl group, or a substituted or unsubstituted naphthyl group, and more preferably an unsubstituted phenyl group, or an unsubstituted naphthyl group.
In the compound according to the exemplary embodiment, preferably, none of a combination(s) of adjacent two or more of R11 to R21 are mutually bonded.
In the compound according to the exemplary embodiment, each independently, R11 to R21 are preferably a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 18 carbon atoms, 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, more preferably a hydrogen atom, 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, and still more preferably a hydrogen atom or an unsubstituted aryl group having 6 to 18 ring carbon atoms.
In the compound according to the exemplary embodiment, each independently, R11 to R21 are preferably a hydrogen atom, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted naphthyl group, and more preferably a hydrogen atom, an unsubstituted phenyl group, or an unsubstituted naphthyl group. In the compound according to the exemplary embodiment, it is also preferable that R11 to R21 are each a hydrogen atom.
In the compound according to the exemplary embodiment, the substituent for the “substituted or unsubstituted” group is preferably a substituted or unsubstituted alkyl group having 1 to 18 carbon atoms, 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, and more preferably 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 compound according to the exemplary embodiment, the groups specified to be “substituted or unsubstituted” are each preferably an “unsubstituted” group.
The compound according to the exemplary embodiment can be produced by, for instance, a method described in later-described Examples. The compound according to the exemplary embodiment can be produced by reactions described in later-described Examples and using known alternative reactions or raw materials suitable for the target compound.
Examples of the compound according to the exemplary embodiment include the following compounds. It should however be noted that the invention is not limited to these specific examples of the compound.
An organic-EL-device material according to a second exemplary embodiment contains a compound according to the first exemplary embodiment (compound represented by the formula (1)).
The organic-EL-device material according to the second exemplary embodiment may further contain any other compound than the compound according to the first exemplary embodiment. When the organic-EL-device material according to the second exemplary embodiment further contains any other compound than the compound according to the first exemplary embodiment, the compound further contained may be solid or liquid.
According to the organic-EL-device material according to the second exemplary embodiment, an organic EL device with high performance is achievable.
An example of the organic-EL-device material according to the second exemplary embodiment, when used as a material for forming an emitting layer, achieves an organic EL device with high performance. According to an example of the second exemplary embodiment, there can be provided a novel organic-EL-device material usable in an organic EL device.
An organic EL device according to a third exemplary embodiment will be described.
The organic EL device according to the third exemplary embodiment includes an organic layer between an anode and a cathode. The organic layer includes at least one layer formed from an organic compound. Alternatively, the organic layer is provided by layering a plurality of layers each formed from an organic compound. The organic layer may further contain an inorganic compound.
In the organic EL device according to the third exemplary embodiment, the organic layer contains a compound according to the first exemplary embodiment. Specifically, the organic EL device according to the exemplary embodiment includes a cathode, an anode, and an organic layer provided between the cathode and the anode, in which at least one layer included in the organic layer contains, as a first compound, a compound according the first exemplary embodiment.
In the organic EL device according to the third exemplary embodiment, it is preferable that the organic layer includes an emitting layer containing the first compound.
The organic EL device according to the third exemplary embodiment includes a cathode, an anode, and one or more emitting layers provided between the cathode and the anode, in which at least one of the one or more emitting layers contains the first compound.
The organic EL device according to an exemplary arrangement of the third exemplary embodiment includes an anode, a cathode, and an emitting layer provided between the anode and the cathode. The emitting layer contains the first compound, which is a compound according to the first exemplary embodiment (compound represented by the formula (1)).
The organic EL device according to an exemplary arrangement of the third exemplary embodiment is an organic EL device including a single emitting layer.
The organic EL device of the third exemplary embodiment preferably emits light having a maximum peak wavelength in a range from 430 nm to 480 nm when the organic EL device is driven.
The maximum peak wavelength of light emitted by the organic EL device when driven is measured as follows. Voltage is applied to the organic EL device such that a current density becomes 10 mA/cm2, where spectral radiance spectrum is measured by a spectroradiometer CS-2000 (produced by Konica Minolta, Inc.). A peak wavelength of an emission spectrum, at which the luminous intensity of the obtained spectral radiance spectrum is at the maximum, is measured and defined as a maximum peak wavelength (unit: nm).
In addition to the emitting layer, the organic EL device according to the third exemplary embodiment may include one or more organic layers. Exemplary organic layers include at least one 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. It should be noted that two or more emitting layers are optionally provided.
In the organic EL device according to the third exemplary embodiment, the organic layer may consist of the emitting layer. Alternatively, for instance, at least one 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 may be further included as the organic layer.
The organic EL device according to the third exemplary embodiment preferably includes the hole transporting layer between the anode and the emitting layer.
The organic EL device according to the third exemplary embodiment preferably includes the electron transporting layer between the cathode and the emitting layer.
Referring to
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 include 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 emitting layer 5 contains, as the first compound, a compound according to the first exemplary embodiment (compound represented by the formula (1)).
The invention is not limited to the organic EL device with the arrangement depicted in
The emitting layer contains the first compound.
In an exemplary arrangement of the third exemplary embodiment, the emitting layer contains the first compound and further a second compound. The first compound and the second compound are mutually different compounds.
In an exemplary arrangement of the third exemplary embodiment, the first compound is preferably a host material (also referred to as a matrix material), and the second compound is preferably a dopant material (also referred to as a guest material, emitter, or luminescent material).
The second compound is preferably a fluorescent compound.
Herein, the “host material” refers to, for instance, a material that accounts for “50 mass % or more of the layer.” Accordingly, for instance, the emitting layer contains 50 mass % or more of the first compound (compound represented by the formula (1)) with respect to the total mass of the emitting layer.
In an exemplary arrangement of the third exemplary embodiment, the emitting layer may contain a metal complex.
In an exemplary arrangement of the third exemplary embodiment, the emitting layer preferably contains no metal complex.
In an exemplary arrangement of the third exemplary embodiment, the emitting layer preferably contains no phosphorescent material.
In an exemplary arrangement of the third exemplary embodiment, the emitting layer preferably contains no heavy metal complex and no phosphorescent rare-earth metal complex. Examples of the heavy metal complex herein include an iridium complex, osmium complex, and platinum complex.
The first compound is a compound according to the first exemplary embodiment (compound represented by the formula (1)).
The second compound is preferably a luminescent material.
Specific examples of the second compound include a bisarylaminonaphthalene derivative, aryl-substituted naphthalene derivative, bisarylaminoanthracene derivative, aryl-substituted anthracene derivative, bisarylaminopyrene derivative, aryl-substituted pyrene derivative, bisarylamino chrysene derivative, aryl-substituted chrysene derivative, bisarylaminofluoranthene derivative, aryl-substituted fluoranthene derivative, indenoperylene derivative, acenaphthofluoranthene derivative, compound including a boron atom, pyromethene boron complex compound, compound having a pyromethene skeleton, metal complex of the compound having a pyrromethene skeleton, diketopyrrolopyrrole derivative, perylene derivative, and naphthacene derivative.
Further, the second compound is exemplified by 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, and a compound represented by a formula (8) below.
Description will be made about the compound represented by the formula (4).
In the formula (4):
The “aromatic hydrocarbon ring” for the ring A1 and the ring A2 has the same structure as a compound formed by introducing a hydrogen atom to the “aryl group having 6 to 50 ring carbon atoms” described above.
Ring atoms of the “aromatic hydrocarbon ring” for the ring A1 and the ring A2 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 “substituted or unsubstituted aryl group” described in the specific example group G1.
The “heterocycle” for the ring A1 and the ring A2 has the same structure as a compound formed by introducing a hydrogen atom to the “heterocyclic group having 5 to 50 ring atoms” described above.
Ring atoms of the “heterocycle” for the ring A1 and the ring A2 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 “substituted or unsubstituted heterocyclic group” described in the specific example group G2.
Rb is bonded to any one of carbon atoms forming the aromatic hydrocarbon ring for the ring A1 or any one of the atoms forming the heterocycle for the ring A1.
Rc is bonded to any one of carbon atoms forming the aromatic hydrocarbon ring for the ring A2 or any one of the atoms forming the heterocycle for the ring A2.
At least one selected from the group consisting of Ra, Rb, and Rc is preferably a group represented by a formula (4a) below. More preferably, at least two selected from the group consisting of Ra, Rb, and Rc are each a group represented by the formula (4a).
*-L401-Ar401 (4a)
In the formula (4a):
In the formula (4b):
In the second compound, R901, R902, R903, R904, R905, R906, and 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 the second compound, it is preferable that R901, R902, R903, R904, R905, R906, and R907 are preferably 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.
Specific examples of the compound represented by the formula (4) include the following compounds.
Description will be made about the compound represented by the formula (5)
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, selected from the group consisting of R501 to R507 and 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.
Specific examples of the compound represented by the formula (5) include the following compounds.
Description will be made about the compound represented by the formula (6).
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 having 6 to 50 ring carbon atoms” 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 “substituted or unsubstituted 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 having 5 to 50 ring atoms” 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 “substituted or unsubstituted 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):
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:
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 aryl 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).
Description will be made about the compound represented by the formula (8).
In the formula (8):
at least one combination of R801 and R802, R802 and R803, and R803 and R804 are mutually bonded to form a divalent group represented by a formula (82) below; and at least one combination of R805 and R806, R806 and R807, and R807 and R808 are mutually bonded to form a divalent group represented by a formula (83) below.
At least one of R801 to R804 not forming the divalent group represented by the formula (82) or R811 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.
Specific examples of the compound represented by the formula (8) include compounds shown below as well as the compounds disclosed in WO 2014/104144.
In addition to the compounds represented by the formula (4), the formula (5), the formula (6), and the formula (8) described above, for instance, the following compounds are usable as the second compound.
Herein, the maximum peak wavelength of fluorescence is occasionally referred to as a maximum fluorescence peak wavelength.
In an exemplary arrangement of the third exemplary embodiment, the second compound is preferably a fluorescent compound that emits fluorescence having a maximum fluorescence peak wavelength in a range from 430 nm to 480 nm.
Herein, the maximum fluorescence peak wavelength refers to the maximum peak wavelength of a fluorescence spectrum exhibiting a maximum luminous intensity among fluorescence spectra measured in a toluene solution in which a measurement target compound is dissolved at a concentration ranging from 10−6 mol/l to 10−5 mol/l. A fluorescence spectrum measurement device (device name: FP-8300, produced by JASCO Corporation) is usable as a measurement device. It should be noted that the fluorescence spectrum measurement device is not limited to the device listed herein.
In an exemplary arrangement of the third exemplary embodiment, when the emitting layer contains the first compound (compound represented by the formula (1)) and the second compound, a singlet energy S1(M1) of the first compound and a singlet energy S1(M2) of the second compound preferably satisfy a relationship of a numerical formula (Numerical Formula 1) below.
The singlet energy S1 means an energy difference between the lowest singlet state and the ground state.
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.
Any apparatus for measuring the absorption spectrum is usable. For instance, a spectrophotometer (U3310 produced 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.
The film thickness of the emitting layer of the organic EL device according to the third exemplary embodiment is preferably in a range from 5 nm to 50 nm, more preferably in a range from 7 nm to 50 nm, and still more preferably in a range from 10 nm to 50 nm. When the film thickness of the emitting layer is 5 nm or more, the emitting layer is easily formable and chromaticity is easily adjustable. When the film thickness of the emitting layer is 50 nm or less, a rise in drive voltage is easily reducible.
When the emitting layer contains the first compound (compound represented by the formula (1)) and the second compound, a content ratio of each of the first compound and the second compound in the emitting layer preferably falls, for instance, within a range below.
The content ratio of the first compound is preferably in a range from 80 mass % to 99 mass %, more preferably in a range from 90 mass % to 99 mass %, and still more preferably in a range from 95 mass % to 99 mass %.
The content ratio of the second compound is preferably in a range from 1 mass % to 10 mass %, more preferably in a range from 1 mass % to 7 mass %, and still more preferably in a range from 1 mass % to 5 mass %.
The upper limit of the total of the content ratios of the first compound and the second compound in the emitting layer is 100 mass %.
The emitting layer of the exemplary embodiment may further contain any other material than the first and second compounds.
The emitting layer may contain a single type of the first compound or may contain two or more types of the first compound. The emitting layer may contain a single type of the second compound or may contain two or more types of the second compound.
According to the third exemplary embodiment, an organic electroluminescence device excellent in performance is achievable.
An organic EL device according to a fourth exemplary embodiment has two or more emitting layers.
The organic EL device according to the fourth exemplary embodiment is different, in having at least two or more emitting layers, from the organic EL device according to the third exemplary embodiment. The rest of the arrangement of the organic EL device according to the fourth exemplary embodiment is the same as in the third exemplary embodiment.
In the description of the fourth exemplary embodiment, the same components as those in the third exemplary embodiment are denoted by the same reference signs and names to simplify or omit description of the components. In the fourth exemplary embodiment, the same materials and compounds as those described in the first and third exemplary embodiments are usable, unless otherwise specified.
Description will be made about an arrangement of the organic EL device according to the fourth exemplary embodiment.
In the organic EL device according to the fourth exemplary embodiment, the emitting layer includes a first emitting layer and a second emitting layer. The first emitting layer contains a first host material and a first dopant material. The second emitting layer contains a second host material and a second dopant material. The first host material and the second host material are different from each other. The first dopant material and the second dopant material are mutually the same or different.
In the organic EL device according to the fourth exemplary embodiment, at least one of the two or more emitting layers is preferably an emitting layer of the organic EL device according to the third exemplary embodiment.
In the organic EL device according to the fourth exemplary embodiment, at least one of the first emitting layer or the second emitting layer is preferably an emitting layer of the organic EL device according to the third exemplary embodiment.
In an exemplary arrangement according to the fourth exemplary embodiment, the first emitting layer is an emitting layer of the organic EL device according to the third exemplary embodiment. In this arrangement, preferably, the first emitting layer contains the first compound (compound represented by the formula (1)) as the first host material and the second compound (preferably a fluorescent compound) as the first dopant material. The second emitting layer may be a fluorescent emitting layer or a phosphorescent emitting layer, preferably a fluorescent emitting layer.
In an exemplary arrangement according to the fourth exemplary embodiment, the second emitting layer is an emitting layer of the organic EL device according to the third exemplary embodiment. In this arrangement, preferably, the second emitting layer contains the first compound (compound represented by the formula (1)) as the second host material and the second compound (preferably a fluorescent compound) as the second dopant material. The first emitting layer may be a fluorescent emitting layer or a phosphorescent emitting layer, preferably a fluorescent emitting layer.
In an exemplary arrangement according to the fourth exemplary embodiment, both the first emitting layer and the second emitting layer are each an emitting layer of the organic EL device according to the third exemplary embodiment. In this arrangement, preferably, the first emitting layer and the second emitting layer each contain the first compound (compound represented by the formula (1)) as the first host material and the second host material and the second compound (preferably a fluorescent compound) as the first dopant material and the second dopant material. The first host material and the second host material are different from each other. The first dopant material and the second dopant material are mutually the same or different.
Examples of the first host material and the second host material include, in addition to the first compound, 1) a metal complex such as an aluminum complex, beryllium complex, or zinc complex; 2) a heterocyclic compound such as an oxadiazole derivative, benzimidazole derivative, or phenanthroline derivative; 3) a fused aromatic compound such as a carbazole derivative, anthracene derivative, phenanthrene derivative, pyrene derivative, or chrysene derivative; and 4) an aromatic amine compound such as a triarylamine derivative or a fused polycyclic aromatic amine derivative.
As the first dopant material and the second dopant material, for instance, the fluorescent compound described in the third exemplary embodiment is usable. Further, as the first dopant material and the second dopant material, a known phosphorescent material is also usable.
When the first emitting layer contains the first compound and the second compound, a content ratio of each of the first compound and the second compound in the first emitting layer preferably falls within the same range as “a content ratio of each of the first compound and the second compound in the emitting layer” described in the third exemplary embodiment. The same applies to a case where the second emitting layer contains the first compound the second compound.
An organic EL device 1A includes a light-transmissive substrate 2, an anode 3, a cathode 4, and organic layers 10A provided between the anode 3 and the cathode 4. The organic layers 10A include a hole injecting layer 6, a hole transporting layer 7, a first emitting layer 51, a second emitting layer 52, an electron transporting layer 8, and an electron injecting layer 9 that are layered on the anode 3 in this order. The first emitting layer 51 is preferably in direct contact with the second emitting layer 52. At least one of the first emitting layer 51 or the second emitting layer 52 contains, as the first compound, a compound according to the first exemplary embodiment (compound represented by the formula (1)). At least one of the first emitting layer 51 or the second emitting layer 52 is an emitting layer according to the third exemplary embodiment.
The invention is not limited to the organic EL device with the arrangement depicted in
According to the fourth exemplary embodiment, an organic electroluminescence device excellent in performance is achievable.
The arrangement of the organic EL device will be further described below. The arrangement described below is common to the organic EL devices according to the third exemplary embodiment and the fourth exemplary embodiment. 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 indium tin oxide (ITO), 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 EL layers formed on the anode, since the hole injecting layer adjacent to the anode is formed of a composite material into which holes are easily injectable irrespective of the work function of the anode, a material usable as an electrode material (e.g., metal, an alloy, an electroconductive compound, a mixture thereof, and the elements belonging to the group 1 or 2 of the periodic table) is also usable for the anode.
The elements belonging to the group 1 or 2 of the periodic table, which are a material having a small work function, specifically, an alkali metal such as lithium (Li) and cesium (Cs), an alkaline earth metal such as magnesium (Mg), calcium (Ca) and strontium (Sr), an alloy containing the alkali metal and the alkaline earth metal (e.g., MgAg, AILi), a rare earth metal such as europium (Eu) and ytterbium (Yb), and an alloy containing 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 materials for the cathode include elements belonging to the group 1 or 2 of the periodic table, specifically, an alkali metal such as lithium (Li) and cesium (Cs), an alkaline earth metal such as magnesium (Mg), calcium (Ca) and strontium (Sr), an alloy containing the alkali metal and the alkaline earth metal (e.g., MgAg, AILi), a rare earth metal such as europium (Eu) and ytterbium (Yb), and an alloy containing the rare earth metal.
It should be noted that the vacuum deposition method and the sputtering method are usable for forming the cathode using the alkali metal, alkaline earth metal and the alloy thereof. Further, when a silver paste is used for the cathode, the coating method and the inkjet method are usable.
By providing the electron injecting layer, various conductive materials such as Al, Ag, ITO, graphene, and indium oxide-tin oxide containing silicon or silicon oxide may be used for forming the cathode regardless of the work function. The conductive materials can be formed into a film using the sputtering method, inkjet method, spin coating method and the like.
The hole injecting layer is a layer containing a substance exhibiting a high hole injectability. Examples of the substance exhibiting a high hole injectability include molybdenum oxide, titanium oxide, vanadium oxide, rhenium oxide, ruthenium oxide, chrome oxide, zirconium oxide, hafnium oxide, tantalum oxide, silver oxide, tungsten oxide, and manganese oxide.
In addition, the examples of the highly hole-injectable substance include: an aromatic amine compound, which is a low-molecule organic compound, such as 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) is also usable.
The hole transporting layer is a layer containing a highly hole-transporting substance. An aromatic amine compound, carbazole derivative, anthracene derivative and the like are usable for the hole transporting layer. Specific examples of a material for the hole transporting layer include 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N, N′-bis(3-methylphenyl)-N, N′-diphenyl-[1,1′-biphenyl]-4,4′-diamine (abbreviation: TPD), 4-phenyl-4′-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: BAFLP), 4,4′-bis[N-(9,9-dimethylfluorene-2-yl)-N-phenylamino]biphenyl (abbreviation: DFLDPBi), 4,4′,4″-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), and 4,4′-bis[N-(spiro-9,9′-bifluorene-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB). The above-described substances mostly have a hole mobility of 10−6 cm2/(V·s) or more.
For the hole transporting layer, a carbazole derivative such as CBP, 9-[4-(N-carbazolyl)]phenyl-10-phenylanthracene (CzPA), and 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (PCzPA) and an anthracene derivative such as t-BuDNA, DNA, and DPAnth may be used. A high polymer compound such as poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyltriphenylamine) (abbreviation: PVTPA) is also usable.
However, in addition to the above substances, any substance exhibiting a higher hole transportability than an electron transportability may be used. It should be noted that the layer containing the substance exhibiting a high hole transportability may be not only a single layer but also a laminate of two or more layers formed of the above substance(s).
In the organic EL device according to the exemplary embodiment, the electron transporting layer is preferably provided between the emitting layer and the cathode.
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-quinolinolato)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 above exemplary embodiment(s), a benzimidazole compound is preferably usable. The above-described substances mostly have an electron mobility of 10−6 cm2/Vs 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.
A method for forming each layer of the organic EL device in the above 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 in each of the above exemplary embodiments 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 fifth exemplary embodiment is installed with the organic EL device according to any of the above exemplary embodiments. Examples of the electronic device include a display device and a light-emitting apparatus. 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 apparatus include an illuminator and a vehicle light.
The scope of the invention is not limited to the above-described exemplary embodiments but includes any modification and improvement as long as such modification and improvement are compatible with the invention.
For instance, the number of emitting layers is not limited to one or two, and more than two emitting layers may be layered. When the organic EL device includes more than two emitting layers, it is only necessary that at least one of the emitting layers should contain the first compound (compound represented by the formula (1)). For instance, the rest of the emitting layers may be a fluorescent emitting layer or a phosphorescent emitting layer with use of emission caused by electron transfer from the triplet excited state directly to the ground state.
When the organic EL device includes a plurality of emitting layers, these emitting layers may be 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.
Examples of the invention will be described below. The invention, however, is not limited to Examples.
Compounds represented by the formula (1) synthesized in Synthesis Examples 1 to 7 below are shown below.
Compounds represented by the formula (1) below were used for producing the organic EL devices in Examples 1 to 7.
Structures of comparative compounds used for producing organic EL devices in Comparatives 1 to 2 are shown below.
Structures of other compounds used for producing organic EL devices in Examples 1 to 7 and Comparatives 1 to 2 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. First, a compound HIL-1 was vapor-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 5-nm-thick hole injecting layer.
Next, the compound HTL-1 was vapor-deposited on the hole injecting layer to form an 80-nm-thick first hole transporting layer.
A compound EBL-1 was then vapor-deposited on the first hole transporting layer to form a 10-nm-thick second hole transporting layer (also referred to as an electron blocking layer).
Next, a compound BH-1 (host material) as the first compound and a compound BD-1 (luminescent compound) as the second compound were co-deposited on the second hole transporting layer to form a 25-nm-thick emitting layer. The ratios of the compound BH-1 and the compound BD-1 in the emitting layer were 96 mass % and 4 mass %, respectively.
Next, a compound HBL-1 was vapor-deposited on the emitting layer to form a 10-nm-thick first electron transporting layer (also referred to as a hole blocking layer).
Next, a compound ET-1 was vapor-deposited on the first electron transporting layer to form a 15-nm-thick second electron transporting layer.
Next, a compound LiF was vapor-deposited on the second electron transporting layer to form a 1-nm-thick electron injecting layer.
Next, 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.
In the device arrangement roughly shown, the numerals in parentheses represent a film thickness (unit: nm). The numerals (96%: 4%) represented by percentage in the same parentheses indicate a ratio (mass %) between the host material (compound BH-1) and the luminescent compound (compound BD-1) in the emitting layer.
The organic EL devices in Examples 2 to 7 were produced as in Example 1 except that the compound BH-1 used in the emitting layer of Example 1 was replaced with compounds shown in Table 1.
The organic EL devices in Comparatives 1 to 2 were produced as in Example 1 except that the compound BH-1 used in the emitting layer of Example 1 was replaced with compounds shown in Table 1.
The organic EL devices produced in Examples 1 to 7 and Comparatives 1 to 2 were evaluated as follows.
Table 1 shows the evaluation results.
Voltage was applied to each organic EL device such that a current density was 1.0 mA/cm2, where spectral radiance spectrum was measured by a spectroradiometer CS-2000 (produced by Konica Minolta, Inc.). The external quantum efficiency EQE (unit: %) was calculated based on the obtained spectral radiance spectra, assuming that the spectra were provided under a Lambertian radiation.
The emitting layers of the organic EL devices in Examples 1 to 7 contain the compounds represented by the formula (1) (first compound).
Since each compound represented by the formula (1) has a structure in which a group with an expanded aromatic ring (a group with an extended conjugated system) is bonded to a position 9 or 10 of an anthracene ring, the carrier transportability thereof is increased. The organic EL devices in Examples 1 to 7 emitted light with higher efficiency than the organic EL devices in Comparatives 1 to 2. Thus, the organic EL device with the compound represented by the formula (1) has improved luminous efficiency.
A synthesis method of the compound BH-1 will be described below.
1,3-dihydroxynaphthalene (10 g) was added to 100 ml of 5%-10% hydrochloric acid/methanol solution and stirred at room temperature for 30 hours. Sodium hydroxide was added to the reaction solution, the organic layer was separated from the reaction mixture, and then the resultant solution was concentrated under reduced pressure. The obtained residue was purified by silica gel column chromatography to obtain an intermediate M-1, which was a pink solid (9.6 g, a yield of 88%).
The intermediate M-1 (8.3 g), 2-bromo-1-fluoronaphthalene (10.7 g), and cesium carbonate (31 g) were added to 240 mL of N-methylpyrrolidone (NMP), and the solution was heated and stirred at 130 degrees C. for seven hours under argon atmosphere. The reaction solution was concentrated, and the obtained residue was purified by silica gel column chromatography to obtain an intermediate M-2, which was a white solid (12.8 g, a yield of 70%).
The intermediate M-2 (12.8 g), palladium acetate (0.8 g), triphenylphosphine (1.8 g), and cesium carbonate (22.1 g) were added to 340 mL of NMP, and the solution was heated and stirred at 170 degrees C. for six hours under argon atmosphere. The reaction solution was concentrated, and the obtained residue was purified by silica gel column chromatography to obtain an intermediate M-3, which was a white solid (6.0 g, a yield of 59%).
The intermediate M-3 (5 g) and sodium hydroxide (2.0 g) were added to 67 mL of NMP, and 1-dodecanethiol (5.1 g) was added thereto under argon atmosphere. After the solution was heated and stirred at 140 degrees C. for six hours, 1N hydrochloric acid was added to acidify the solution. The organic layer was collected by extraction with a mixed solvent of a hexane and ethyl acetate, and the resultant solution was concentrated under reduced pressure. Accordingly, an intermediate M-4, which was an oily yellow substance (4.6 g, a yield of 97%), was obtained.
The intermediate M-4 (4.4 g) and pyridine (3.7 g) were added to 160 mL of dichloromethane, and the solution was stirred at 0 degrees C. under argon atmosphere. Trifluoromethanesulfonic anhydride (Tf2O, 6.6 g) was added dropwise, and the solution was stirred at room temperature for two hours. The reaction solution was concentrated under reduced pressure, and the obtained residue was purified by silica gel column chromatography to obtain an intermediate M-5, which was a white solid (1.9 g, a yield of 29%).
The intermediate M-5 (1.8 g), 10-(1-naphthyl) anthracene-9-boronic acid (1.8 g), Pd2(dba)3 (0.08 g), SPhos (0.14 g), and cesium carbonate (2.8 g) were added to 40 mL of 1,4-dioxane, and the solution was heated and stirred at 90 degrees C. for six hours. The reaction solution was concentrated under reduced pressure, and the obtained residue was purified by silica gel column chromatography and then recrystallized to obtain an intermediate BH-1, which was a light yellow solid (1.6 g, a yield of 65%).
A compound BH-2 was obtained as a light yellow solid (a yield of 68%) in accordance with the synthesis method of the compound BH-1 except that 10-phenylanthracene-9-boronic acid was used in place of 10-(1-naphthyl) anthracene-9-boronic acid.
Synthesis of Compound BH-3 A compound BH-3 was obtained as a light yellow solid (a yield of 59%) in accordance with the synthesis method of the compound BH-1 except that 10-(1,1′-biphenyl-3-yl) anthracene-9-boronic acid was used in place of 10-(1-naphthyl) anthracene-9-boronic acid.
A compound BH-4 was obtained as a light yellow solid (a yield of 70%) in accordance with the synthesis method of the compound BH-1 except that a boronic acid M-6 was used in place of 10-(1-naphthyl) anthracene-9-boronic acid.
A compound BH-5 was obtained as a light yellow solid (a yield of 47%) in accordance with the synthesis method of the compound BH-1 except that an intermediate M-7 synthesized in accordance with the description of WO2016/190600 was used in place of the intermediate M-5.
An intermediate M-9 was synthesized from an intermediate M-8 (CASNo.; 2848670-74-4) in accordance with the synthesis method of the compound M-5. Subsequently, a compound BH-6 was obtained as a light yellow solid (a yield of 40%) in accordance with the synthesis method of the compound BH-2 except that the intermediate M-9 was used in place of the intermediate M-5.
A compound BH-7 was obtained as a light yellow solid (a yield of 57%) in accordance with the synthesis method of the compound BH-1 except that an intermediate M-10 (CASNo.; 2254559-38-9) was used in place of the intermediate M-5.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-203858 | Dec 2022 | JP | national |
