WO2022255427A1

WO2022255427A1 - Aromatic compound, organic electroluminescence element, composition, and method for producing organic electroluminescence element

Info

Publication number: WO2022255427A1
Application number: PCT/JP2022/022396
Authority: WO
Inventors: 延軍李; 一毅岡部; 麻未山下; 司長谷川; 大輔弘; 麻優子奈良
Original assignee: 三菱ケミカル株式会社
Priority date: 2021-06-04
Filing date: 2022-06-01
Publication date: 2022-12-08
Also published as: TW202313571A; JPWO2022255427A1; KR20240016968A; CN117480154A

Abstract

The present invention addresses the problem of providing an aromatic compound which exhibits excellent heat resistance and high solubility, has a structure in which molecules have a structure in which an aggregated structure is unlikely to be formed and in which the charge balance can be easily adjusted, and has excellent resistance to alcoholic solvents following film formation. The present invention relates to an aromatic compound represented by formula (1). (In formula (1), G¹, G², X¹ to X⁷ and G are as defined in the description.)

Description

Aromatic compound, organic electroluminescent device, composition, and method for producing organic electroluminescent device

The present invention provides an aromatic compound that can be used in an organic electroluminescent device (hereinafter sometimes referred to as "OLED" or "device"), an organic electroluminescent device having the compound, and the organic electroluminescent device. The present invention relates to a display device and a lighting device, a composition containing the compound and the solvent, a method for forming a thin film, and a method for manufacturing an organic electroluminescent device.

The present invention relates to an aromatic compound that can be used in the light-emitting layer of an organic electroluminescent device to increase the luminous efficiency of the device and to obtain a device with a long operating life. In addition, the present inventors have found a compound that is insoluble in an alcoholic solvent and can be laminated and coated on the layer containing the aromatic compound of the present invention using a solution of an alcoholic solvent. It is a thing. The present invention also relates to an organic electroluminescence device containing these aromatic compounds and a method for producing the same.

As a method for manufacturing an organic electroluminescence element, a method of forming a film of an organic material by a vacuum deposition method and laminating it is common. is formed by an ink jet method or the like, and research on a manufacturing method by a wet film forming method for laminating is becoming active.

In order to form an organic electroluminescent element by laminating a plurality of layers by wet film formation, it is necessary to make the thin film after application insoluble in the composition applied to the upper layer. In general, the most stable method is to give the composition a cross-linking group or a polymerizable group, and then treat it after coating to form a bond to make it insoluble.

However, in an organic electroluminescent device using a functional material having a cross-linking group or a polymerizable group in the light-emitting layer, the reaction of the cross-linking group or the polymerizable group may adversely affect the life and luminous efficiency of the device due to the action of radicals. I know it.

When forming an electron transport layer on top of the light-emitting layer by coating, as a method of insolubilization using a functional material that does not contain a cross-linking group or a polymerizable group in the light-emitting layer, for a compound composed of linked heterocyclic compounds, A method is adopted in which low molecules having a higher molecular weight are partially insoluble by treatment such as heating using a highly polar alcohol-based solvent, and the remainder is washed away to use only the insolubilized portion.

By the way, in the technique of insolubilizing a compound composed of linked heterocyclic compounds by heat treatment using a highly polar alcohol-based solvent, Patent Document 1 discloses an organic electroluminescent device containing a triazine-substituted indolecarbazole derivative as shown below. It is disclosed that voltage drive and high efficiency are realized.

Patent Document 2 discloses the following carbazole derivatives that are insoluble in alcoholic solvents having 3 to 6 carbon atoms, and discloses that organic electroluminescence devices containing these derivatives achieve high efficiency and long life. ing.

Patent Document 3 discloses compounds containing the following biscarbazole skeletons, and discloses that an organic electroluminescence device containing these compounds in the light-emitting layer realizes high efficiency and long life.

Patent Document 4 discloses compounds containing the following biscarbazole skeletons, and an organic electroluminescence device having these compounds in the light-emitting layer and having the electron-transporting layer prepared by vapor deposition has high efficiency and long life. It is disclosed to be realized.

Japanese Patent Application Laid-Open No. 2017-145198 WO2009/104488 Japanese special table 2019-525463 Japanese Patent Application Laid-Open No. 2020-105152

However, since the carbazole derivative has a large content of carbazole groups per molecule, it has better charge transportability and tends to form an aggregation structure of molecules. Further, when the carbazole derivative has a low aromatic hydrocarbon group content per molecule of the biscarbazole derivative, the glass transition temperature (Tg) of the compound is low, and the electron transport composition ink using alcohol as a solvent is used. When the electron transport layer is formed, there is a drawback that the solvent resistance of the light-emitting layer is insufficient. In addition, since the carbazole derivative has a low aromatic hydrocarbon group content per molecule, when the carbazole derivative is used as a host in the light-emitting layer, the charge balance of the light-emitting layer tends to be disturbed. Furthermore, when the carbazole derivative is used, it is not sufficient to achieve high efficiency and long life of the organic electroluminescence device.

The present invention has been made in view of the above-mentioned conventional circumstances, and has excellent heat resistance and high solubility. An object of the present invention is to provide an aromatic compound having excellent resistance to alcohol-based solvents after film formation.

The present invention also provides an organic electroluminescence device containing the aromatic compound, a display device and a lighting device containing the organic electroluminescence device, a composition containing the compound and a solvent, a method for forming a thin film, and production of the organic electroluminescence device. The object is to provide a method.

As a result of extensive studies by the present inventors, it was found that by using an aromatic compound with a specific structure, the aromatic compound has excellent heat resistance, high solubility, molecules are less likely to form an aggregate structure, and the charge The inventors have found that it is easy to adjust the balance and have excellent durability against alcohol solvents after film formation, and have arrived at the present invention.

That is, the gist of the present invention is as follows <1> to <20>.
<1>
An aromatic compound represented by the following formula (1).

(In formula (1), G ¹ and G ² each independently represent an aromatic hydrocarbon group, X ¹ to X ⁷ are each independently CR ^1A or a nitrogen atom, and R ^1A appears each independently represents a hydrogen atom, a deuterium atom, CN, or an optionally substituted aromatic hydrocarbon group having from 6 to 30 carbon atoms, G is a hydrogen atom, a deuterium atom , CN, an optionally substituted aromatic hydrocarbon group having 6 to 30 carbon atoms, or formula (2).

In formula (2), ^G3 represents an aromatic hydrocarbon group. X ¹⁵ to X ²¹ are each independently CR ^1B or a nitrogen atom, and each occurrence of R ^1B may independently be a hydrogen atom, a deuterium atom, CN, or have a substituent It represents an aromatic hydrocarbon group having 6 to 30 carbon atoms.
When G is a hydrogen atom, a deuterium atom, CN, or an optionally substituted aromatic hydrocarbon group having 6 to 30 carbon atoms, at least one of G ¹ and G ² has 54 to 240, and when G has the above formula (2), at least one of G ¹ , G ² and G ³ has 28 to 240 carbon atoms.
* represents the binding site)
<2>
The aromatic compound according to <1>, represented by the following formula (1-A).

(In formula (1-A), G ^A represents a hydrogen atom, a deuterium atom, CN, or an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent. X ¹ to X ⁷ , G ¹ and G ² are as defined for formula (1) above.)
<3>
The aromatic compound according to <1>, represented by the following formula (1-B).

(In formula (1-B), X ⁸ to X ¹⁴ are defined in the same manner as X ¹ to X ⁷ in formula (1) above. X ¹⁵ to X ²¹ are as defined in formula (2) above. and G ¹ , G ² and G ³ are as defined for formulas (1) and (2) above.)
<4>
At least one of G ¹ or G ² is the following formula (17-2), the following formula (20-2), the following formula (13), the following formula (14), the following formula (15), or the following formula (16) The aromatic compound according to <2>, comprising a partial structure represented by:

<5>
At least one of G ¹ to G ³ is the following formula (17-2), the following formula (20-2), the following formula (13), the following formula (14), the following formula (15), or the following formula (16) The aromatic compound according to <3>, comprising a partial structure represented by:

<6>
The substituents that the aromatic hydrocarbon group having 6 to 30 carbon atoms of R ^1A and ^GA may have are each independently an aromatic hydrocarbon group having 6 to 30 carbon atoms.
The aromatic compound according to <2>.
<7>
The substituents that the aromatic hydrocarbon group having 6 to 30 carbon atoms of R ^1A and R ^1B may have are each independently an aromatic hydrocarbon group having 6 to 30 carbon atoms.
The aromatic compound according to <3>.
<8>
An organic electroluminescence device having an anode and a cathode on a substrate, and an organic layer between the anode and the cathode, wherein at least one of the organic layers comprises any one of <1> to <7>. An organic electroluminescence device comprising the aromatic compound according to 1.
<9>
The organic electroluminescent device according to <8>, wherein the layer containing the aromatic compound is a light-emitting layer.
<10>
A display device comprising the organic electroluminescent element according to <8> or <9>.

<11>
A lighting device comprising the organic electroluminescent element according to <8> or <9>.
<12>
A composition for forming a light-emitting layer of an organic electroluminescent device, comprising the aromatic compound according to any one of <1> to <7> and a solvent.
<13>
The composition according to <12>, further comprising a phosphorescent material and a charge-transporting material.
<14>
The composition according to <13>, wherein the charge-transporting material contains at least one of a compound represented by the following formula (250) and a compound represented by the following formula (260).

(In formula (250),
W each independently represents CH or N, at least one W is N,
Xa ¹ , Ya ¹ , and Za ¹ are each independently an optionally substituted divalent aromatic hydrocarbon group having 6 to 30 carbon atoms, or an optionally substituted carbon represents a divalent aromatic heterocyclic group of numbers 3 to 30,
Xa ² , Ya ² and Za ² are each independently a hydrogen atom, a monovalent aromatic hydrocarbon group optionally having 6 to 30 carbon atoms, or optionally having a substituent represents a good monovalent aromatic heterocyclic group having 3 to 30 carbon atoms,
g11, h11, and j11 each independently represents an integer of 0 to 6,
at least one of g11, h11, and j11 is an integer of 1 or more;
When g11 is 2 or more, multiple Xa ¹ may be the same or different,
When h11 is 2 or more, multiple Ya ¹ may be the same or different,
When g11 is 2 or more, multiple Za ¹ may be the same or different,
R ³¹ represents a hydrogen atom or a substituent, the four R ³¹ may be the same or different,
However, when g11, h11 or j11 is 0, the corresponding Xa ² , Ya ² and Za ² are not hydrogen atoms. )

(In the formula (260), each of Ar ²¹ to Ar ³⁵ is independently a hydrogen atom, an optionally substituted phenyl group or an optionally substituted phenyl group, 2 to 10, unbranched or represents a branched and linked monovalent group.)
<15>
The composition according to <14>, wherein at least two of W in the formula (250) are N.
<16>
The composition according to <14>, wherein all W in the formula (250) are N.
<17>
In the formula (260), Ar ²¹ , Ar ²⁵ , Ar ²⁶ , Ar ³⁰ , Ar ³¹ and Ar ³⁵ are hydrogen atoms,
Ar ²² to Ar ²⁴ , Ar ²⁷ to Ar ²⁹ , and Ar ³² to Ar ³⁴ are hydrogen atoms, phenyl groups, or structures selected from the following formulas (261-1) to (261-9). The composition according to <14>, wherein these structures may have an alkyl group having 1 to 12 carbon atoms as a substituent.

<18>
A method for forming a thin film, comprising the step of forming a film from the composition according to any one of <12> to <17> by a wet film-forming method.
<19>
A method for producing an organic electroluminescence device having an anode and a cathode on a substrate and an organic layer between the anode and the cathode, the method comprising:
the organic layer comprises a light-emitting layer and an electron-transporting layer;
forming the light-emitting layer by a wet film-forming method using the composition according to any one of <12> to <17>; A method for producing an organic electroluminescence device, comprising a step of forming a layer by a wet film-forming method using the layer composition.
<20>
The method for producing an organic electroluminescence device according to <19>, wherein the solvent contained in the electron transport layer composition is an alcohol solvent.

According to the present invention, while having excellent heat resistance and high solubility, the molecules are unlikely to form an aggregate structure, the structure is easy to adjust the charge balance, and excellent resistance to alcohol solvents after film formation. can provide an aromatic compound with

FIG. 1 is a cross-sectional view schematically showing an example of the structure of the organic electroluminescence device of the present invention.

Although the embodiments of the present invention will be described in detail below, the present invention is not limited to the following embodiments, and can be variously modified within the scope of the gist of the invention.

In the present invention, "optionally having a substituent" means that it may have one or more substituents.

<Aromatic compound of the present invention>
The aromatic compound of the present invention is an aromatic compound represented by the following formula (1).

In formula (2), ^G3 represents an aromatic hydrocarbon group. X ¹⁵ to X ²¹ are each independently CR ^1B or a nitrogen atom, and each occurrence of R ^1B may independently be a hydrogen atom, a deuterium atom, CN, or have a substituent It represents an aromatic hydrocarbon group having 6 to 30 carbon atoms.
When G is a hydrogen atom, a deuterium atom, CN, or an optionally substituted aromatic hydrocarbon group having 6 to 30 carbon atoms, at least one of G ¹ and G ² has 54 to 240, and when G has the above formula (2), at least one of G ¹ , G ² and G ³ has 28 to 240 carbon atoms. * represents the binding site)

The above formula (1) includes both the following formula (1-A) and the following formula (1-B), and G is a hydrogen atom, a deuterium atom, CN, even if it has a substituent In the case of an aromatic hydrocarbon group having 6 to 30 carbon atoms, formula (1) is represented by formula (1-A), and when G is represented by formula (2), formula (1) is represented by formula (1 -B).

(In formula (1-A), G ^A represents a hydrogen atom, a deuterium atom, CN, or an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent. X ¹ to X ⁷ , G ¹ and G ² are as defined for formula (1) above.)

(In formula (1-B), X ⁸ to X ¹⁴ are defined in the same manner as X ¹ to X ⁷ in formula (1) above. X ¹⁵ to X ²¹ are as defined in formula (2) above. and G ¹ , G ² and G ³ are as defined for formula (1) and formula (2).)

<X ¹ to X ⁷ , X ⁸ to X ¹⁴ , X ¹⁵ to X ²¹ >
X ¹ to X ⁷ are each independently CR ^1A or a nitrogen atom, preferably CR ^1A .
X ⁸ to X ¹⁴ are each independently CR ^1A or a nitrogen atom, preferably CR ^1A .
X ¹⁵ to X ²¹ are each independently CR ^1B or a nitrogen atom, preferably CR ^1B .

It is preferred that all of X ¹ to X ⁷ are CR ^1A , that is, the ring containing X ¹ to X ⁷ is a carbazole ring.
It is preferred that all of X ⁸ to X ¹⁴ are CR ^1A , that is, the ring containing X ⁸ to X ¹⁴ is a carbazole ring.
It is preferred that all of X ¹⁵ to X ²¹ are CR ^1B , that is, the ring containing X ¹⁵ to X ²¹ is a carbazole ring.

<R ^1A , R ^1B >
Each occurrence of R ^1A and R ^1B independently represents a hydrogen atom, a deuterium atom, CN, or an optionally substituted aromatic hydrocarbon group having 6 to 30 carbon atoms.

R ^1A and R ^1B are preferably hydrogen atoms or aromatic hydrocarbon groups having 6 to 30 carbon atoms.

<G>
In formula (1), G represents a hydrogen atom, a deuterium atom, CN, an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or formula (2) above. From the viewpoint of solubility of aromatic compounds in solvents, G is preferably a hydrogen atom, a deuterium atom, or an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent. and more preferably a hydrogen atom.

^<GA>
In formula (1-A), G ^A is defined in the same manner as R ^1A above. From the viewpoint of electron durability, ^GA is preferably a hydrogen atom, a deuterium atom, or an aromatic hydrocarbon group optionally having 6 to 30 carbon atoms, more preferably a hydrogen atom. .

<Aromatic hydrocarbon group>
In Formula (1), Formula (2), Formula (1-A) and Formula (1-B), R ^1A , R ^1B , G and G ^A are aromatic hydrocarbon groups having 6 to 30 carbon atoms; The aromatic hydrocarbon group in some cases is preferably an aromatic hydrocarbon group having 24 or less carbon atoms, more preferably an aromatic hydrocarbon group having 18 or less carbon atoms. Preferred aromatic hydrocarbon groups are phenyl group, naphthyl group, anthracenyl group, benzoanthracenyl group, phenanthrenyl group, benzophenanthrenyl group, pyrenyl group, chrysenyl group, fluoranthenyl group, perylenyl group and benzopyrenyl group. , a benzofluoranthenyl group, a naphthacenyl group, a pentacenyl group, a biphenyl group, or a terphenyl group.
In Formula (1), Formula (2), Formula (1-A) and Formula (1-B), R ^1A , R ^1B , G and G ^A are aromatic hydrocarbon groups having 6 to 30 carbon atoms; The substituents which the aromatic hydrocarbon group may have in some cases are preferably aromatic hydrocarbon groups. The aromatic hydrocarbon group as a substituent is preferably an aromatic hydrocarbon group having 6 to 30 carbon atoms, more preferably an aromatic hydrocarbon group having 24 or less carbon atoms, and more preferably 18 or less carbon atoms. is an aromatic hydrocarbon group. Examples of aromatic hydrocarbon groups as substituents include phenyl, naphthyl, anthracenyl, benzoanthracenyl, phenanthrenyl, benzophenanthrenyl, pyrenyl, chrysenyl, fluoranthenyl, and perylenyl. a benzopyrenyl group, a benzofluoranthenyl group, a naphthacenyl group, a pentacenyl group, a biphenyl group, a terphenyl group, or a combination of two or more of these, for example, a naphthyl group substituted with a phenyl group, a phenanthrenyl group substituted with a phenyl group, etc. , are mentioned.
From the viewpoint of ease of synthesis or charge transport property, in formula (1), formula (2), formula (1-A) and formula (1-B), R ^1A , R ^1B , G and G ^A When is an aromatic hydrocarbon group having 6 to 30 carbon atoms, the aromatic hydrocarbon group preferably has no substituent.
As used herein, the term "aromatic hydrocarbon group" refers to a group in which all carbons are involved in aromaticity and are unsubstituted.

< ^G1 to ^G3 >
Each of G ¹ to G ³ independently represents an aromatic hydrocarbon group, and the number of carbon atoms in the aromatic hydrocarbon group is preferably 6 or more, more preferably 24 or more, still more preferably 28 or more, and particularly preferably 30 or more, particularly preferably 54 or more, and most preferably 60 or more. Also, the number of carbon atoms is preferably 240 or less, more preferably 180 or less, and even more preferably 120 or less.
When G is a hydrogen atom, a deuterium atom, CN, or an optionally substituted aromatic hydrocarbon group having 6 to 30 carbon atoms, at least one of G ¹ and G ² has 54 to 240. More preferably, both G ¹ and G ² have 54-240 carbon atoms. Further, the total number of carbon atoms of ^G1 and ^G2 is preferably 240 or less.
When G has the above formula (2), at least one of G ¹ , G ² and G ³ has 28 to 240 carbon atoms. More preferably, all of G ¹ , G ² and G ³ have 28-240 carbon atoms. Further, the total number of carbon atoms of ^G1 , ^G2 and ^G3 is preferably 240 or less.

When G is a hydrogen atom, a deuterium atom, CN, or an optionally substituted aromatic hydrocarbon group having 6 to 30 carbon atoms, at least one of G ¹ and G ² has 54 to 240, or when G is the above formula (2), at least one of G ¹ , G ² and G ³ has 28 to 240 carbon atoms, the electron transport property of the aromatic compound of the present invention is Therefore, it is considered that the driving voltage of the device is low and the luminous efficiency is high. When G is a hydrogen atom, a deuterium atom, CN, or an aromatic hydrocarbon group having from 6 to 30 carbon atoms which may have a substituent, the number of carbon atoms in both G ¹ and G ² is 54 to 240, or when G is the above formula (2) and all of G ¹ , G ² and G ³ have 28 to 240 carbon atoms. When G is a hydrogen atom, a deuterium atom, CN, or an optionally substituted aromatic hydrocarbon group having 6 to 30 carbon atoms, at least one of G ¹ and G ² has less than 54 carbon atoms or when G is the above formula (2) and at least one of G ¹ , G ² and G ³ has less than 28 carbon atoms, the crystallinity of the compound may be improved and aggregation may occur. There is On the other hand, when the number of carbon atoms in G ¹ , G ² and G ³ exceeds 240, the drive voltage of the device may increase and the luminous efficiency may decrease.

When G is a hydrogen atom, a deuterium atom, CN, or an optionally substituted aromatic hydrocarbon group having 6 to 30 carbon atoms, at least one of G ¹ and G ² has 54 or more carbon atoms. and preferably 60 or more. In this case, it is more preferable that both G ¹ and G ² have 54 or more carbon atoms, and particularly preferably both G ¹ and G ² have 60 or more carbon atoms.
At least one of G ¹ , G ² and G ³ when G is the above formula (2) has 28 or more carbon atoms, preferably 30 or more. In this case, all of G ¹ , G ² and G ³ preferably have 28 or more carbon atoms, and particularly preferably all of G ¹ , G ² and G ³ have 30 or more carbon atoms.
When G is a hydrogen atom, a deuterium atom, CN, or an optionally substituted aromatic hydrocarbon group having 6 to 30 carbon atoms, at least one of G ¹ and G ² has 240 or less carbon atoms. , preferably 180 or less, particularly preferably 120 or less. More preferably, both G ¹ and G ² have 240 or less carbon atoms, more preferably both G ¹ and G ² have 180 or less carbon atoms, and particularly preferably both G ¹ and G ² have carbon atoms. The number is 120 or less.
At least one of G ¹ , G ² and G ³ when G is the above formula (2) has 240 or less carbon atoms, preferably 180 or less, and particularly preferably 120 or less. More preferably, all of G ¹ , G ² and G ³ have 240 or less carbon atoms, more preferably all of G ¹ , G ² and G ³ have 180 or less carbon atoms, and particularly preferably G ¹ , All of G ² and G ³ have 120 or less carbon atoms.

In G ¹ , G ² and G ³ , the aromatic hydrocarbon group includes a benzene ring, naphthalene ring, anthracene ring, tetraphenylene ring, phenanthrene ring, chrysene ring, pyrene ring, benzanthracene ring, or perylene ring. A monovalent aromatic hydrocarbon structure having a carbon number of usually 6 or more, usually 30 or less, preferably 18 or less, more preferably 10 or less, or a plurality of structures selected from these structures in a chain or a monovalent group having a branched and bonded structure. Preferably, a monovalent group in which a plurality of benzene rings are bonded in a plurality of chains or branches, or a plurality of benzene rings and at least one naphthalene ring, at least one phenanthrene ring, or at least one tetraphenylene ring It is a monovalent group in which a plurality of benzene rings are bonded in a chain or branched manner, and most preferably a monovalent group in which a plurality of benzene rings are bonded in a chain or branched manner.

When the aromatic hydrocarbon group in G ¹ , G ² and G ³ contains a benzene ring as a phenylene group, at least one of the phenylenes is preferably bonded at the meta-position or ortho-position.

At least one of G ¹ to G ³ preferably has at least one partial structure selected from the following formulas ⁽ 11) to (16) from the viewpoint of compound solubility and durability. It is more preferable that all of G ³ when ² and G are of formula (2) have at least one partial structure selected from the following formulas (11) to (16).

In each of the above formulas (11) to (16), * represents a bond with an adjacent structure or a hydrogen atom, and at least one of the two * represents a bonding position with an adjacent structure. In the following description, the definition of * is the same unless otherwise specified.

More preferably, at least one of G ¹ to G ³ has at least one partial structure selected from formulas (11) to (14). More preferably, all of G ¹ , G ² and G ³ when G is formula (2) have at least one partial structure selected from formulas (11) to (14).
More preferably, each of G ¹ to G ³ has at least one partial structure selected from formulas (11) to (13). More preferably, all of G ¹ , G ² and G ³ when G is formula (2) have at least one partial structure selected from formulas (11) to (13).
Particularly preferably, each of G ¹ to G ³ has at least one partial structure selected from formulas (11) to (12). More preferably, all of G ¹ , G ² and G ³ when G is formula (2) have at least one partial structure selected from formulas (11) to (1s2).

Formula (12) is preferably the following formula (12-2).

Formula (12) is more preferably formula (12-3) below.

Further, from the viewpoint of the solubility and durability of the compound, the partial structure that at least one of G ¹ to G ³ preferably has includes the partial structure represented by formula (11) and the partial structure represented by formula (12). A partial structure having The partial structure having the partial structure represented by formula (11) and the partial structure represented by formula (12) is present in all of G ¹ , G ² and G ³ when G is represented by formula (2). is more preferred.

As the partial structure having the partial structure represented by formula (11) and the partial structure represented by formula (12), the partial structure represented by formula (11) and the partial structure represented by formula (12) A partial structure represented by at least one selected from the following formulas (17) to (22), which is a structure containing a plurality of selected structures, is more preferable.

The structure containing a plurality of structures selected from the partial structure represented by formula (11) and the partial structure represented by formula (12) is, for example, formula (17), such as the following formula (17a), It is a partial structure that can be regarded as having one partial structure represented by (11) and two partial structures represented by formula (12).

More preferably, at least one of G ¹ to G ³ has at least the partial structure represented by formula (17) or the partial structure represented by formula (18). More preferably, when G ¹ , G ² and G are formula (2), all of G ³ have at least the partial structure represented by formula (17) or the partial structure represented by formula (18) .

Formula (17) is preferably the following formula (17-2).

Formula (17) is more preferably the following formula (17-3).

Formula (18) is preferably the following formula (18-2).

Formula (18) is more preferably formula (18-3) below.

Formula (20) is preferably the following formula (20-2).

Formula (21) is preferably the following formula (21-2).

Formula (22) is preferably the following formula (22-2).

From the viewpoint of solubility and durability of the compound, at least one of G ¹ , G ² and G ³ , or all of G ³ when G ¹ , G ² and G are of formula (2) is It is particularly preferable to contain the partial structure represented by -2).

Further, at least one of G ¹ , G ² and G ³ , or all of G ³ when G ¹ , G ² and G are of formula (2) has a partial structure represented by formula (13) As the containing partial structure, it is more preferable to have at least one partial structure selected from the following formulas (13-2) to (13-4).

Further, at least one of G ¹ , G ² and G ³ , or all of G ³ when G ¹ , G ² and G are of formula (2) has a partial structure represented by formula (14) As the containing partial structure, it is more preferable to have at least one partial structure selected from the following formulas (14-2) to (14-3).

Further, at least one of G ¹ , G ² and G ³ , or all of G ³ when G ¹ , G ² and G are of formula (2) has a partial structure represented by formula (15) As the containing partial structure, it is more preferable to have at least one partial structure selected from the following formulas (15-2) to (15-3).

Further, at least one of G ¹ , G ² and G ³ , or all of G ³ when G ¹ , G ² and G are of formula (2) has a partial structure represented by formula (16) As the containing partial structure, it is more preferable to have at least one partial structure selected from the following formulas (16-2) to (16-3).

In each of the above formulas (13-2) to (16-3), * represents a bond with an adjacent structure or a hydrogen atom, and at least one of the two * represents a bonding position with an adjacent structure.

Among formulas (13-2) to (16-3), formulas (13-2) to (14-3) are preferred, and formulas (13-2) to (13-4) are more preferred.

From the viewpoint of electronic durability, in formula (1-A), at least one or both of G ¹ and G ² are represented by formula (17-2), formula (20-2), formula (13), and formula (14). , Formula (15) or Formula (16).

Similarly, from the viewpoint of electronic durability, in Formula (1-B), at least one of G ¹ to G 3 or all of G ¹ to ^{G 3} ^is represented by Formula (17-2), Formula (20- 2), it preferably contains a partial structure represented by formula (13), formula (14), formula (15) or formula (16).

Further, in the formulas (1-A) and (1-B), the structure in which the heterocyclic structure is bonded to the carbazole structure, which is the basic skeleton, has a high degree of planarity and tends to serve as a molecular packing site. At least one of G ¹ and G ² of the aromatic compound represented by formula (1-A) has 54 to 240 carbon atoms, and G ¹ and G of the aromatic compound represented by formula (1-B) Since at least one of ² and ^G3 has a carbon number of 28 to 240, the degree of freedom of the molecular packing site is weakened, which relaxes the aggregation of molecules, and the ink containing such a compound has high stability. High uniformity of films formed from compositions containing such compounds can be expected. This effect is obtained when both G ¹ and G ² in the aromatic compound represented by formula (1-A) have 54 to 240 carbon atoms, or in the aromatic compound represented by formula (1-B). It is expected that G ¹ , G ² and G ³ all have 28 to 240 carbon atoms to be higher.

At least one of G ¹ and G ² in the aromatic compound represented by formula (1-A) of the present invention has 54 to 240 carbon atoms, and G of the aromatic compound represented by formula (1-B) At least one of ¹ , G ² and G ³ has 28-240 carbon atoms. As a result, both the aromatic compound represented by formula (1-A) and the aromatic compound represented by formula (1-B) have a molecular weight of at least 1000 or more, and the density of the formed film is It is possible to reduce the swellability of the membrane to the solvent and to make the membrane insoluble. This effect is obtained when both G ¹ and G ² of the aromatic compound represented by formula (1-A) have 54 to 240 carbon atoms, or Higher values are expected with all G ¹ , G ² and G ³ of the aromatic compound having 28 to 240 carbon atoms. In addition, since the aromatic compound of the present invention has a molecular packing site with a high degree of freedom, its solubility in solvents is low, making it possible to make the film insoluble.
In addition, when a composition containing an alcohol solvent is applied to the film containing the aromatic compound of the present invention, the alcohol solvent has a relatively low ability to swell the film, so that the insolubilization rate of the film is kept high. be able to.

The aromatic compound of the present invention has a heterocyclic structure bonded to the carbazole structure, which is the basic skeleton. When the heterocyclic structure is a carbazole ring, the HOMO of the molecule is distributed over two carbazole rings, which improves the electronic durability of the molecule. It is presumed that the organic electroluminescence element contained in the light-emitting layer can have a long life.

When G ¹ , G ² , and G ³ of the aromatic compound of the present invention are aromatic hydrocarbon groups in which benzene rings are linked at the meta-position or ortho-position, the solubility of the compound in solvents is improved, and ink is produced. When doing so, the number of types of solvents to be selected increases, and a simple manufacturing process for the organic electroluminescence device can be realized.

<Substituent>
Substituents used in the aromatic compound of the present invention include alkyl groups, alkenyl groups, alkynyl groups, alkoxy groups, aryloxy groups, alkoxycarbonyl groups, acyl groups, halogen atoms, haloalkyl groups, alkylthio groups, arylthio groups, and silyl groups. groups, siloxy groups, cyano groups, aralkyl groups, or aromatic hydrocarbon groups.

The alkyl group includes, for example, a methyl group, an ethyl group, a branched, straight-chain or cyclic propyl group, a branched, straight-chain or cyclic butyl group, a branched, straight-chain or cyclic pentyl group, a branched, straight-chain or cyclic A hexyl group, a branched, straight-chain or cyclic octyl group, a branched, straight-chain or cyclic nonyl group, a branched, straight-chain or cyclic dodecyl group, etc., usually having 1 or more carbon atoms, preferably 4 or more, and usually Linear, branched or cyclic alkyl groups with 24 or less, preferably 10 or less are mentioned. From the viewpoint of compound stability, a methyl group, an ethyl group, a branched, linear or cyclic propyl group, and a branched, linear or cyclic butyl group are preferred, and a branched propyl group is particularly preferred.

Examples of alkenyl groups include alkenyl groups having usually 2 or more carbon atoms and usually 24 or less, preferably 12 or less carbon atoms such as vinyl groups.

Examples of alkynyl groups include alkynyl groups having usually 2 or more carbon atoms and usually 24 or less, preferably 12 or less carbon atoms such as ethynyl groups.

Examples of alkoxy groups include alkoxy groups having usually 1 or more carbon atoms and usually 24 or less, preferably 12 or less carbon atoms such as methoxy and ethoxy groups.

The aryloxy group includes, for example, an aryloxy group or heteroaryl having usually 4 or more, preferably 5 or more carbon atoms and usually 36 or less, preferably 24 or less, such as phenoxy group, naphthoxy group, pyridyloxy group, etc. An oxy group can be mentioned.

The alkoxycarbonyl group includes, for example, an alkoxycarbonyl group having usually 2 or more carbon atoms, usually 24 or less, preferably 12 or less, such as a methoxycarbonyl group and an ethoxycarbonyl group.

The acyl group includes, for example, an acyl group having usually 2 or more carbon atoms, usually 24 or less, preferably 12 or less, such as an acetyl group and a benzoyl group.

Examples of halogen atoms include halogen atoms such as fluorine atoms and chlorine atoms.

The haloalkyl group includes, for example, a haloalkyl group having usually 1 or more carbon atoms, usually 12 or less, preferably 6 or less, such as a trifluoromethyl group.

The alkylthio group includes, for example, an alkylthio group having usually 1 or more carbon atoms, usually 24 or less, preferably 12 or less, such as a methylthio group or an ethylthio group.

Examples of the arylthio group include arylthio groups having usually 4 or more, preferably 5 or more carbon atoms and usually 36 or less, preferably 24 or less carbon atoms such as phenylthio, naphthylthio, and pyridylthio groups.

The silyl group includes, for example, a silyl group having usually 2 or more, preferably 3 or more carbon atoms, and usually 36 or less, preferably 24 or less carbon atoms such as trimethylsilyl group and triphenylsilyl group.

Siloxy groups include, for example, siloxy groups having usually 2 or more, preferably 3 or more carbon atoms and usually 36 or less, preferably 24 or less carbon atoms such as trimethylsiloxy and triphenylsiloxy groups.

Examples of aralkyl groups include benzyl, 2-phenylethyl, 2-phenylpropyl-2-yl, 2-phenylbutyl-2-yl, 3-phenylpentyl-3-yl, 3-phenyl- 1-propyl group, 4-phenyl-1-butyl group, 5-phenyl-1-pentyl group, 6-phenyl-1-hexyl group, 7-phenyl-1-heptyl group, 8-phenyl-1-octyl group, etc. and an aralkyl group having usually 7 or more, preferably 9 or more carbon atoms and usually 30 or less, preferably 18 or less, more preferably 10 or less carbon atoms.

Examples of the aromatic hydrocarbon group include, for example, benzene ring, naphthalene ring, anthracene ring, tetraphenylene ring, phenanthrene ring, chrysene ring, pyrene ring, benzanthracene ring, or perylene ring. An aromatic hydrocarbon group having a number of 30 or less, preferably 18 or less, more preferably 10 or less can be mentioned.

Among the above substituents, alkyl groups, alkoxy groups, aralkyl groups, and aromatic hydrocarbon groups are preferred, and alkyl groups having 10 or less carbon atoms, aralkyl groups having 30 or less carbon atoms, and 30 or less carbon atoms are more preferred. is more preferably an aromatic hydrocarbon group having 30 or less carbon atoms, particularly preferably having no substituent.

In addition, the substituent may further have a substituent. As the additional substituents that may be present, the same substituents as those described above can be used. Preferably, the above substituents have no further substituents.

<Molecular weight>
The molecular weight of the aromatic compound of the present invention is preferably 1090 or more, more preferably 1200 or more, particularly preferably 1300 or more, most preferably 1400 or more, preferably 5000 or less, more preferably 4000 or less. It is preferably 3,000 or less, and most preferably 2,500 or less.

<Specific example>
Specific examples of the aromatic compound of the invention are shown below, but the invention is not limited thereto.

<Method for Producing Aromatic Compound of the Present Invention>
The aromatic compound of the present invention can be produced, for example, according to the method described in Examples.

<Use of the aromatic compound of the present invention>
The aromatic compound of the present invention is preferably used in an organic layer of an organic electroluminescent device, and the organic layer is preferably a light-emitting layer. When the aromatic compound of the present invention is used in the light-emitting layer, it is preferably used as a host material for the light-emitting layer.

In the light-emitting layer, the charge-transporting material transports electrons and holes, and in formula (1), at least one of G ¹ and G ² has 54 to 240 carbon atoms, and G is the above formula (2 ), at least one of G ¹ , G ² and G ³ has an aromatic hydrocarbon ring group having 28 to 240 carbon atoms, which suppresses the transport of electrons and holes, thereby adjusting the carrier balance in the light-emitting layer. do. In addition, by containing a large amount of the aromatic hydrocarbon ring group, aggregation of the charge-transporting material can be suppressed, thereby improving the efficiency and durability of the organic electroluminescence device.

In addition, since the aromatic compound of the present invention has a large energy gap (difference between HOMO and LUMO), a high excited triplet level (T1), and a high hole transport property, it may be included in the charge transport layer. can.

The organic layer containing the aromatic compound of the present invention is preferably formed by a wet film-forming method. The light-emitting layer containing the aromatic compound of the present invention is particularly preferably formed by a wet film-forming method because a more uniform film can be formed.

<Solubility of the aromatic compound of the present invention>
The aromatic compound of the present invention preferably dissolves in cyclohexylbenzene in an amount of 2% by mass or more, more preferably 5% by mass or more in cyclohexylbenzene.

As will be described later, aromatic hydrocarbons are preferred as the solvent contained in the composition for organic electroluminescence devices. Cyclohexylbenzene is cited as a representative example of aromatic hydrocarbons, and the solubility in cyclohexylbenzene is used as an indicator of the solubility of the aromatic compound of the present invention.

When the solubility of the aromatic compound of the present invention in cyclohexylbenzene is 2% by mass or more, the layers constituting the organic electroluminescent device can be easily formed by a wet film-forming method, which is preferable. Although the upper limit of the solubility is not particularly limited, it is usually about 50% by mass.

<Composition>
When the organic layer containing the aromatic compound of the present invention is wet film-formed, at least the aromatic compound represented by the formula (1), the formula (1-A) or the formula (1-B) and a solvent (hereinafter , also referred to as an “organic solvent”) is wet film-formed. That is, the composition of the present invention contains at least the aromatic compound represented by formula (1), formula (1-A) or formula (1-B) and an organic solvent. Moreover, it is preferable to use the composition of this invention as a composition for light emitting layer formation.

The composition of the present invention preferably further contains a luminescent material, and is suitably used as a composition for forming a luminescent layer of an organic electroluminescent device. For example, the composition for forming a light-emitting layer of the present invention can further contain a phosphorescent light-emitting material and a charge-transporting material, which will be described later.

<Organic solvent>
The organic solvent contained in the composition of the present invention is a volatile liquid component used for forming the layer containing the aromatic compound of the present invention by wet film formation.

The organic solvent is not particularly limited as long as it is an organic solvent in which the aromatic compound of the present invention, which is the solute, and the luminescent material described later are well dissolved.

Preferred organic solvents include alkanes such as n-decane, cyclohexane, ethylcyclohexane, decalin and bicyclohexane; aromatic hydrocarbons such as toluene, xylene, mesitylene, phenylcyclohexane, tetralin and methylnaphthalene; chlorobenzene, dichlorobenzene, Halogenated aromatic hydrocarbons such as trichlorobenzene; 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethyl anisole, 2,4-dimethylanisole, diphenyl ether and other aromatic ethers; phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, n-butyl benzoate and other aromatic esters; cyclohexanone, Alicyclic ketones such as cyclooctanone and Fencon; Alicyclic alcohols such as cyclohexanol and cyclooctanol; Aliphatic ketones such as methyl ethyl ketone and dibutyl ketone; Aliphatic alcohols such as butanol and hexanol; Ethylene glycol dimethyl ether , ethylene glycol diethyl ether, propylene glycol-1-monomethyl ether acetate (PGMEA) and other aliphatic ethers;

Among these, from the viewpoint of viscosity and boiling point, alkanes, aromatic hydrocarbons, aromatic ethers, and aromatic esters are preferred, and aromatic hydrocarbons, aromatic ethers, and aromatic esters are more preferred. , aromatic hydrocarbons and aromatic esters are particularly preferred.

One type of these organic solvents may be used alone, or two or more types may be used in any combination and ratio.

The boiling point of the organic solvent used is usually 80°C or higher, preferably 100°C or higher, more preferably 120°C or higher, and usually 380°C or lower, preferably 350°C or lower, more preferably 330°C or lower. If the boiling point of the organic solvent is below this range, the film formation stability may decrease due to evaporation of the solvent from the composition during wet film formation. If the boiling point of the organic solvent exceeds this range, there is a possibility that the film formation stability will decrease due to the residual solvent after film formation during wet film formation.

In particular, by combining two or more organic solvents having a boiling point of 150° C. or higher among the above organic solvents, a uniform coating film can be produced. If the number of organic solvents having a boiling point of 150° C. or higher is less than one, it is considered that a uniform film may not be formed during coating.

<Luminescent material>
The composition of the present invention is preferably a composition for forming a light-emitting layer, and in this case, it preferably further contains a light-emitting material. A luminescent material refers to a component that mainly emits light in the composition for an organic electroluminescent element of the present invention, and corresponds to a dopant component in an organic electroluminescent device.

As the light-emitting material, a known material can be applied, and a fluorescent light-emitting material or a phosphorescent light-emitting material can be used singly or in combination, but from the viewpoint of internal quantum efficiency, phosphorescent light-emitting materials are preferable.

(Phosphorescent material)
A phosphorescent material is a material that emits light from an excited triplet state. For example, metal complex compounds containing Ir, Pt, Eu, etc. are typical examples, and materials containing metal complexes are preferable as the structure of the material.

Among metal complexes, the long-period periodic table (unless otherwise specified, the long-period periodic table ) include Werner-type complexes or organometallic complex compounds containing a metal selected from Groups 7 to 11 as a central metal. As such a phosphorescent material, a compound represented by the following formula (201) or a compound represented by the following formula (205) is preferable, and a compound represented by the following formula (201) is more preferable.

M is a metal selected from Groups 7 to 11 of the periodic table, such as ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, gold, and europium.

Ring A1 represents an optionally substituted aromatic hydrocarbon ring structure or an optionally substituted aromatic heterocyclic ring structure.

Ring A2 represents an aromatic heterocyclic structure which may have a substituent.

R ²⁰¹ and R ²⁰² each independently represent a structure represented by formula (202) above, and "*" represents bonding to ring A1 or ring A2. R ²⁰¹ and R ²⁰² may be the same or different, and when multiple R ²⁰¹ and R ²⁰² are present, they may be the same or different.

Ar ²⁰¹ and Ar ²⁰³ each independently represent an optionally substituted aromatic hydrocarbon ring structure or an optionally substituted aromatic heterocyclic ring structure.

Ar ²⁰² is an optionally substituted aromatic hydrocarbon ring structure, an optionally substituted aromatic heterocyclic ring structure, or an optionally substituted aliphatic hydrocarbon structure represents

The substituents bonded to ring A1, the substituents bonded to ring A2, or the substituents bonded to ring A1 and the substituents bonded to ring A2 may be bonded to each other to form a ring.

B ²⁰¹ -L ²⁰⁰ -B ²⁰² represents an anionic bidentate ligand. B ²⁰¹ and B ²⁰² each independently represent a carbon atom, an oxygen atom or a nitrogen atom, and these atoms may be atoms constituting a ring. L ²⁰⁰ represents a single bond or an atomic group forming a bidentate ligand together with B ²⁰¹ and B ²⁰² . When there are multiple groups of B ²⁰¹ -L ²⁰⁰ -B ²⁰² , they may be the same or different.

i1 and i2 each independently represent an integer of 0 or more and 12 or less.
i3 is an integer greater than or equal to 0 up to the number that can be substituted for Ar ²⁰² .
j is an integer greater than or equal to 0 up to the number that can be substituted for Ar ²⁰¹ .
k1 and k2 are each independently an integer of 0 or more, with the upper limit being the number that can be substituted on ring A1 and ring A2.
m is an integer of 1-3.

The aromatic hydrocarbon ring for ring A1 is preferably an aromatic hydrocarbon ring having 6 to 30 carbon atoms, and specifically includes a benzene ring, naphthalene ring, anthracene ring, triphenylyl ring, acenaphthene ring, fluoranthene ring, A fluorene ring is preferred.

The aromatic heterocyclic ring in ring A1 is preferably an aromatic heterocyclic ring having 3 to 30 carbon atoms containing any one of a nitrogen atom, an oxygen atom, or a sulfur atom as a heteroatom, more preferably a furan ring or a benzofuran ring. , thiophene ring, and benzothiophene ring.

The ring A1 is more preferably a benzene ring, a naphthalene ring or a fluorene ring, particularly preferably a benzene ring or a fluorene ring, most preferably a benzene ring.

The aromatic heterocyclic ring for ring A2 is preferably an aromatic heterocyclic ring having 3 to 30 carbon atoms containing either a nitrogen atom, an oxygen atom, or a sulfur atom as a heteroatom, specifically a pyridine ring. , pyrimidine ring, pyrazine ring, triazine ring, imidazole ring, oxazole ring, thiazole ring, benzothiazole ring, benzoxazole ring, benzimidazole ring, quinoline ring, isoquinoline ring, quinoxaline ring, quinazoline ring, naphthyridine ring, phenanthridine ring more preferably pyridine ring, pyrazine ring, pyrimidine ring, imidazole ring, benzothiazole ring, benzoxazole ring, quinoline ring, isoquinoline ring, quinoxaline ring, quinazoline ring, more preferably pyridine ring, imidazole ring, benzothiazole ring, quinoline ring, isoquinoline ring, quinoxaline ring and quinazoline ring, most preferably pyridine ring, imidazole ring, benzothiazole ring, quinoline ring, quinoxaline ring and quinazoline ring.

Preferred combinations of ring A1 and ring A2 are represented by (ring A1-ring A2), (benzene ring-pyridine ring), (benzene ring-quinoline ring), (benzene ring-quinoxaline ring), (benzene ring- quinazoline ring), (benzene ring-imidazole ring), and (benzene ring-benzothiazole ring).

The substituents that ring A1 and ring A2 may have may be arbitrarily selected, but are preferably one or more substituents selected from the group S of substituents described below.

When any one of Ar ²⁰¹ , Ar ²⁰² and Ar ²⁰³ is an aromatic hydrocarbon ring structure which may have a substituent, the aromatic hydrocarbon ring structure is preferably an aromatic ring structure having 6 to 30 carbon atoms. A hydrocarbon ring, specifically preferably a benzene ring, a naphthalene ring, anthracene ring, a triphenylyl ring, an acenaphthene ring, a fluoranthene ring, or a fluorene ring, more preferably a benzene ring, a naphthalene ring, or a fluorene ring, most preferably A benzene ring is preferred.

When any of Ar ²⁰¹ , Ar ²⁰² and Ar ²⁰³ is a fluorene ring optionally having a substituent, the 9- and 9′-positions of the fluorene ring have a substituent or are bonded to the adjacent structure. preferably.

When any of Ar ²⁰¹ , Ar ²⁰² and Ar ²⁰³ is a benzene ring optionally having a substituent, at least one benzene ring is preferably bonded to the adjacent structure at the meta-position or para-position. , more preferably, at least one benzene ring is attached to the adjacent structure at the meta position.

When any one of Ar ²⁰¹ , Ar ²⁰² and Ar ²⁰³ is an aromatic heterocyclic structure which may have a substituent, the aromatic heterocyclic structure preferably contains a nitrogen atom, an oxygen atom, or An aromatic heterocyclic ring having 3 to 30 carbon atoms containing any of a sulfur atom, specifically, a pyridine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, an imidazole ring, an oxazole ring, a thiazole ring, and a benzothiazole ring. , benzoxazole ring, benzimidazole ring, quinoline ring, isoquinoline ring, quinoxaline ring, quinazoline ring, naphthyridine ring, phenanthridine ring, carbazole ring, dibenzofuran ring, dibenzothiophene ring, more preferably pyridine ring, pyrimidine ring ring, triazine ring, carbazole ring, dibenzofuran ring, and dibenzothiophene ring.

When any of Ar ²⁰¹ , Ar ²⁰² and Ar ²⁰³ is a carbazole ring optionally having a substituent, the N-position of the carbazole ring may have a substituent or be bonded to an adjacent structure. preferable.

When Ar ²⁰² is an optionally substituted aliphatic hydrocarbon structure, the aliphatic hydrocarbon structure is an aliphatic hydrocarbon structure having a linear, branched, or cyclic structure, preferably It is an aliphatic hydrocarbon having 1 or more and 24 or less carbon atoms, more preferably an aliphatic hydrocarbon having 1 or more and 12 or less carbon atoms, and more preferably an aliphatic hydrocarbon having 1 or more and 8 or less carbon atoms. .

i1 and i2 are each independently preferably an integer of 1-12, more preferably an integer of 1-8, more preferably an integer of 1-6. Within this range, improved solubility and improved charge transport properties can be expected.

i3 preferably represents an integer of 0 to 5, more preferably an integer of 0 to 2, more preferably 0 or 1.

j preferably represents an integer of 0 to 2, more preferably 0 or 1.

k1 and k2 preferably represent integers of 0 to 3, more preferably integers of 1 to 3, more preferably 1 or 2, and particularly preferably 1.

The substituents that Ar ²⁰¹ , Ar ²⁰² and Ar ²⁰³ may have can be arbitrarily selected, but are preferably one or more substituents selected from the group S of substituents described later, more preferably hydrogen It is an atom, an alkyl group or an aryl group, particularly preferably a hydrogen atom or an alkyl group, and most preferably unsubstituted (hydrogen atom).

Unless otherwise specified, the substituent is preferably a group selected from the following substituent group S.

<Substituent Group S>
- an alkyl group, preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, particularly preferably an alkyl group having 1 to 6 carbon atoms .
- An alkoxy group, preferably an alkoxy group having 1 to 20 carbon atoms, more preferably an alkoxy group having 1 to 12 carbon atoms, and still more preferably an alkoxy group having 1 to 6 carbon atoms.
- an aryloxy group, preferably an aryloxy group having 6 to 20 carbon atoms, more preferably an aryloxy group having 6 to 14 carbon atoms, still more preferably an aryloxy group having 6 to 12 carbon atoms, particularly preferably an aryloxy group having 6 carbon atoms; aryloxy group.
- A heteroaryloxy group, preferably a heteroaryloxy group having 3 to 20 carbon atoms, more preferably a heteroaryloxy group having 3 to 12 carbon atoms.
- an alkylamino group, preferably an alkylamino group having 1 to 20 carbon atoms, more preferably an alkylamino group having 1 to 12 carbon atoms;
- An arylamino group, preferably an arylamino group having 6 to 36 carbon atoms, more preferably an arylamino group having 6 to 24 carbon atoms.
- An aralkyl group, preferably an aralkyl group having 7 to 40 carbon atoms, more preferably an aralkyl group having 7 to 18 carbon atoms, and still more preferably an aralkyl group having 7 to 12 carbon atoms.
- A heteroaralkyl group, preferably a heteroaralkyl group having 7 to 40 carbon atoms, more preferably a heteroaralkyl group having 7 to 18 carbon atoms.
- an alkenyl group, preferably an alkenyl group having 2 to 20 carbon atoms, more preferably an alkenyl group having 2 to 12 carbon atoms, still more preferably an alkenyl group having 2 to 8 carbon atoms, particularly preferably an alkenyl group having 2 to 6 carbon atoms .
- an alkynyl group, preferably an alkynyl group having 2 to 20 carbon atoms, more preferably an alkynyl group having 2 to 12 carbon atoms;
- An aryl group, preferably an aryl group having 6 to 30 carbon atoms, more preferably an aryl group having 6 to 24 carbon atoms, still more preferably an aryl group having 6 to 18 carbon atoms, particularly preferably an aryl group having 6 to 14 carbon atoms .
- a heteroaryl group, preferably a heteroaryl group having 3 to 30 carbon atoms, more preferably a heteroaryl group having 3 to 24 carbon atoms, still more preferably a heteroaryl group having 3 to 18 carbon atoms, particularly preferably 3 to 3 carbon atoms 14 heteroaryl groups.
An alkylsilyl group, preferably an alkylsilyl group having 1 to 20 carbon atoms, more preferably an alkylsilyl group having 1 to 12 carbon atoms.
- An arylsilyl group, preferably an arylsilyl group in which the aryl group has 6 to 20 carbon atoms, more preferably an arylsilyl group in which the aryl group has 6 to 14 carbon atoms.
- an alkylcarbonyl group, preferably an alkylcarbonyl group having 2 to 20 carbon atoms;
- an arylcarbonyl group, preferably an arylcarbonyl group having 7 to 20 carbon atoms;
- A hydrogen atom, a deuterium atom, a fluorine atom, a cyano group, or -SF ₅ .

In the above groups, one or more hydrogen atoms may be replaced with fluorine atoms, or one or more hydrogen atoms may be replaced with deuterium atoms.

Unless otherwise specified, aryl is an aromatic hydrocarbon and heteroaryl is an aromatic heterocycle.

(Preferred Group in Substituent Group S)
Of these substituent groups S, preferably an alkyl group, an alkoxy group, an aryloxy group, an arylamino group, an aralkyl group, an alkenyl group, an aryl group, a heteroaryl group, an alkylsilyl group, an arylsilyl group, or A group in which one or more hydrogen atoms are replaced with a fluorine atom, a fluorine atom, a cyano group, or _-SF5 , more preferably an alkyl group, an arylamino group, an aralkyl group, an alkenyl group, an aryl group, a hetero an aryl group, a group in which one or more hydrogen atoms of these groups are replaced with a fluorine atom, a fluorine atom, a cyano group, or _-SF5 , more preferably an alkyl group, an alkoxy group, or an aryloxy group , an arylamino group, an aralkyl group, an alkenyl group, an aryl group, a heteroaryl group, an alkylsilyl group, an arylsilyl group,
Particularly preferred are alkyl groups, arylamino groups, aralkyl groups, alkenyl groups, aryl groups and heteroaryl groups, and most preferred are alkyl groups, arylamino groups, aralkyl groups, aryl groups and heteroaryl groups.

These substituent group S may further have a substituent selected from the substituent group S as a substituent. Preferred groups, more preferred groups, further preferred groups, particularly preferred groups, and most preferred groups of the substituents which may be present are the same as the preferred groups in Substituent Group S and the like.

(preferred structure of formula (201))
Among the structures represented by the above formula (202) in the above formula (201), a structure having a group to which a benzene ring is linked, an aromatic hydrocarbon in which an alkyl group or an aralkyl group is bonded to ring A1 or ring A2 A structure having a group or an aromatic heterocyclic group, and a structure in which a dendron is bonded to ring A1 or ring A2 are preferred.

In the structure having a group to which benzene rings are linked, Ar ²⁰¹ is a benzene ring structure, i1 is 1 to 6, and at least one of the benzene rings is bonded to the adjacent structure at the ortho- or meta-position. .
This structure is expected to improve the solubility and the charge transport property.

In a structure having an aromatic hydrocarbon group or aromatic heterocyclic group to which an alkyl group or an aralkyl group is bonded to ring A1 or ring A2,
Ar ²⁰¹ is an aromatic hydrocarbon structure or an aromatic heterocyclic structure, i1 is 1 to 6, Ar ²⁰² is an aliphatic hydrocarbon structure, i2 is 1 to 12, preferably 3 to 8 , Ar ²⁰³ is a benzene ring structure, and i3 is 0 or 1.
In this structure, Ar ²⁰¹ is preferably the above aromatic hydrocarbon structure, more preferably a structure in which 1 to 5 benzene rings are linked, and more preferably one benzene ring.
This structure is expected to improve the solubility and the charge transport property.

In the structure in which a dendron is bound to ring A1 or ring A2, Ar ²⁰¹ and Ar ²⁰² are benzene ring structures, Ar ²⁰³ is a biphenyl or terphenyl structure, i1 and i2 are 1 to 6, and i3 is 2 and j is 2.
This structure is expected to improve the solubility and the charge transport property.

Among the structures represented by B ²⁰¹ -L ²⁰⁰ -B ²⁰² , structures represented by the following formula (203) or (204) are preferable.

R ²¹¹ , R ²¹² and R ²¹³ represent substituents.
Although the substituent is not particularly limited, it is preferably a group selected from the substituent group S described above.

Ring B3 represents an aromatic heterocyclic structure containing a nitrogen atom, which may have a substituent.
Ring B3 is preferably a pyridine ring.
Although the substituent that ring B3 may have is not particularly limited, it is preferably a group selected from the substituent group S described above.

Although the phosphorescent material represented by formula (201) is not particularly limited, specific examples include the following structures.
In addition, Me means a methyl group and Ph means a phenyl group.

Here, the compound represented by the following formula (205) will be explained.

In formula (205), ^M2 represents a metal and T represents a carbon or nitrogen atom. R ⁹² to R ⁹⁵ each independently represent a substituent. However, when T is a nitrogen atom, ^R94 and ^R95 do not exist.

In formula (205), ^M2 represents a metal. Specific examples include metals selected from groups 7 to 11 of the periodic table. Among them, ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum and gold are preferred, and divalent metals such as platinum and palladium are particularly preferred.

In formula (205), R ⁹² and R ⁹³ each independently represent a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an amino group, an acyl group, an alkoxycarbonyl group, a carboxyl group, represents an alkoxy group, an alkylamino group, an aralkylamino group, a haloalkyl group, a hydroxyl group, an aryloxy group, an aromatic hydrocarbon group or an aromatic heterocyclic group;

Furthermore, when T is a carbon atom, ^R94 and ^R95 each independently represent a substituent represented by the same examples as ^R92 and ^R93 . Also, when T is a nitrogen atom, there is no ^R94 or ^R95 directly bonded to said T.

In addition, R ⁹² to R ⁹⁵ may further have a substituent. Substituents can be the aforementioned substituents exemplified for R ⁹² and R ⁹³ . Furthermore, any two or more groups selected from R ⁹² to R ⁹⁵ may be linked together to form a ring.

(molecular weight)
The molecular weight of the phosphorescent material is preferably 5,000 or less, more preferably 4,000 or less, and particularly preferably 3,000 or less. Further, the molecular weight of the phosphorescent material is usually 1000 or more, preferably 1100 or more, more preferably 1200 or more. It is believed that within this molecular weight range, the phosphorescent light-emitting materials do not aggregate with each other and are uniformly mixed with the aromatic compound of the present invention and/or other charge-transporting materials, making it possible to obtain a light-emitting layer with high light-emitting efficiency. .

The molecular weight of the phosphorescent light-emitting material has a high Tg, melting point, decomposition temperature, etc., and the phosphorescent light-emitting material and the formed light-emitting layer have excellent heat resistance, and the film quality due to gas generation, recrystallization, molecular migration, etc. A large value is preferable from the viewpoint that it is difficult to cause a decrease in the concentration of impurities and an increase in the concentration of impurities due to thermal decomposition of the material. On the other hand, the molecular weight of the phosphorescent light-emitting material is preferably small in terms of facilitating purification of the organic compound.

[Charge transport material]
When the composition of the present invention is a composition for forming a light emitting layer, it preferably contains a charge transport material as a further host material in addition to the aromatic compound of the present invention.

The charge-transporting material used as the host material of the light-emitting layer is a material having a skeleton with excellent charge-transporting properties, and is selected from electron-transporting materials, hole-transporting materials, and bipolar materials capable of transporting both electrons and holes. is preferred. Furthermore, in the present invention, the charge-transporting material also includes a material that adjusts the charge-transporting property.

Specific examples of skeletons with excellent charge transport properties include aromatic structures, aromatic amine structures, triarylamine structures, dibenzofuran structures, naphthalene structures, phenanthrene structures, phthalocyanine structures, porphyrin structures, thiophene structures, benzylphenyl structures, fluorene structure, quinacridone structure, triphenylene structure, carbazole structure, pyrene structure, anthracene structure, phenanthroline structure, quinoline structure, pyridine structure, pyrimidine structure, triazine structure, oxadiazole structure, imidazole structure, and the like.

As the electron-transporting material, a compound having a pyridine structure, a pyrimidine structure, or a triazine structure, which has an excellent electron-transporting property and a relatively stable structure, is more preferable, and a compound having a pyrimidine structure or a triazine structure is even more preferable. Particularly preferred is a compound represented by formula (250) described later.

The hole-transporting material is a compound having a structure with excellent hole-transporting properties, and among the skeletons with excellent charge-transporting properties, a carbazole structure, a dibenzofuran structure, a triarylamine structure, a naphthalene structure, a phenanthrene structure, or a pyrene structure. A carbazole structure, a dibenzofuran structure, or a triarylamine structure is more preferable as a structure having excellent hole transport properties. The aromatic compound of the present invention is particularly preferred as the hole transport material.

The charge-transporting material used as the host material of the light-emitting layer is preferably a compound having a condensed ring structure of three or more rings, and at least a compound having two or more condensed ring structures of three or more rings or a condensed ring of five or more rings. Compounds having one are more preferred. These compounds increase the rigidity of the molecules, making it easier to obtain the effect of suppressing the degree of molecular motion in response to heat. Further, the 3 or more condensed rings and the 5 or more condensed rings preferably have an aromatic hydrocarbon ring or an aromatic heterocyclic ring from the viewpoint of charge transportability and material durability.

Specific examples of condensed ring structures having three or more rings include anthracene structure, phenanthrene structure, pyrene structure, chrysene structure, naphthacene structure, triphenylene structure, fluorene structure, benzofluorene structure, indenofluorene structure, indolofluorene structure, Carbazole structure, indenocarbazole structure, indolocarbazole structure, dibenzofuran structure, dibenzothiophene structure and the like.

At least one selected from the group consisting of a phenanthrene structure, a fluorene structure, an indenofluorene structure, a carbazole structure, an indenocarbazole structure, an indolocarbazole structure, a dibenzofuran structure, and a dibenzothiophene structure, from the viewpoints of charge transportability and solubility. A carbazole structure or an indolocarbazole structure is more preferred from the viewpoint of resistance to electric charge.

As the material for adjusting the charge transport property used as the host material of the light-emitting layer, a compound represented by the below-described formula (260), which is a compound having a structure in which a large number of benzene rings are linked, is preferable. By including this compound as a host material, it is thought that the excitons generated in the light-emitting layer are efficiently recombined to increase the light-emitting efficiency. deterioration is suppressed, and the driving life is lengthened.

When the composition of the present invention is a composition for forming a light-emitting layer, in addition to the aromatic compound of the present invention having excellent hole-transport properties, a compound represented by the formula (250) described later as a further host material, and/or Alternatively, it preferably contains a compound represented by formula (260) described later. Inclusion of such a material as an additional host material is preferable from the viewpoint of charge balance adjustment in the light-emitting layer and from the viewpoint of luminous efficiency.

The composition for forming a light-emitting layer of the present invention can contain a phosphorescent light-emitting material and a charge-transporting material. At least one of the compounds represented by can be contained.

(molecular weight)
The charge-transporting material used as the host material of the light-emitting layer is preferably a polymeric material from the viewpoint of excellent flexibility. A light-emitting layer formed using a material having excellent flexibility is preferable as a light-emitting layer of an organic electroluminescent device formed on a flexible substrate. When the charge-transporting material used as the host material contained in the light-emitting layer is a polymeric material, the molecular weight is preferably 5,000 or more and 1,000,000 or less, more preferably 10,000 or more and 500,000 or less, It is more preferably 10,000 or more and 100,000 or less.

In addition, the charge transport material used as the host material of the light emitting layer is easy to synthesize and purify, easy to design the electron transport performance and hole transport performance, and easy to adjust the viscosity when dissolved in a solvent. From the viewpoint of, it is preferably a low molecular weight. When the charge-transporting material used as the host material contained in the light-emitting layer is a low-molecular-weight material, the molecular weight is preferably 5,000 or less, more preferably 4,000 or less, and particularly preferably 3,000 or less. , most preferably 2,500 or less, usually 800 or more, preferably 900 or more, and when the electron transport layer formed in contact with the light emitting layer is formed by a wet film formation method, preferably It is 1000 or more, more preferably 1100 or more, and particularly preferably 1200 or more.

The compound represented by formula (250) above is preferably a charge transport compound, that is, a charge transport host material.

<W>
W in the formula (250) represents CH or N, at least one of which is N, but from the viewpoint of electron transport properties and electron durability, at least two are preferably N, and all are N It is more preferable to have

< ^Xa1 , ^Ya1 , ^Za1 , ^Xa2 , ^Ya2 , ^Za2 >
Xa ¹ , Ya ¹ and Za ¹ in the formula (250) are divalent aromatic hydrocarbon groups having 6 to 30 carbon atoms which may have a substituent; and Xa ² and Ya ² , Za ² is an optionally substituted aromatic hydrocarbon group having 6 to 30 carbon atoms, the aromatic hydrocarbon ring of the aromatic hydrocarbon group having 6 to 30 carbon atoms is 6 A single membered ring or 2 to 5 condensed rings are preferred. Specific examples thereof include benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, fluorene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, fluoranthene ring, and indenofluorene ring. Among them, benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, or fluorene ring is preferable, benzene ring, naphthalene ring, phenanthrene ring, or fluorene ring is more preferable, and benzene ring, naphthalene ring, or fluorene ring is still more preferable. be.

When Xa ¹ , Ya ¹ and Za ¹ in the formula (250) are an optionally substituted divalent aromatic heterocyclic group having 3 to 30 carbon atoms, and Xa ² and Ya ² , Za ² is an optionally substituted aromatic heterocyclic group having 3 to 30 carbon atoms, the aromatic heterocyclic ring of the aromatic heterocyclic group having 3 to 30 carbon atoms is 5 or A 6-membered monocyclic ring or 2 to 5 condensed rings are preferred. Specifically, furan ring, benzofuran ring, dibenzofuran ring, thiophene ring, benzothiophene ring, dibenzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, indolocarbazole ring, indenocarbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzisoxazole ring, benzisothiazole ring, benzimidazole ring, pyridine ring, Pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, shinoline ring, quinoxaline ring, perimidine ring, quinazoline ring, quinazolinone ring and the like. Among them, thiophene ring, pyrrole ring, imidazole ring, pyridine ring, pyrimidine ring, triazine ring, quinoline ring, quinazoline ring, carbazole ring, dibenzofuran ring, dibenzothiophene ring, indolocarbazole ring, phenanthroline ring, or indenocarbazole ring are preferred. and more preferably a pyridine ring, a pyrimidine ring, a triazine ring, a quinoline ring, a quinazoline ring, a carbazole ring, a dibenzofuran ring or a dibenzothiophene ring, and still more preferably a carbazole ring, a dibenzofuran ring or a dibenzothiophene ring.

Particularly preferred aromatic hydrocarbon rings for Xa ¹ , Ya ¹ , Za ¹ , Xa ² , Ya ² and Za ² in the formula (250) are benzene ring, naphthalene ring and phenanthrene ring, and particularly preferred aromatic hydrocarbon rings. A heterocyclic ring is a carbazole ring, a dibenzofuran ring or a dibenzothiophene ring.

<g11, h11, j11>
g11, h11, and j11 each independently represents an integer of 0 to 6, and at least one of g11, h11, and j11 is an integer of 1 or more. From the viewpoint of charge transportability and durability, g11 is preferably 2 or more, or at least one of h11 and j11 is preferably 3 or more.

In addition, the compound represented by the formula (250) should have a total of 8 to 18 of these rings, including a ring having three central Ws, to improve charge transport properties, durability, and resistance to organic solvents. from the viewpoint of the solubility of

^<R31>
R ³¹ when it is a substituent is preferably an optionally substituted aromatic hydrocarbon group having 6 to 30 carbon atoms or an optionally substituted aromatic hydrocarbon group having 3 to 30 carbon atoms. is a heterocyclic group. From the viewpoint of durability improvement and charge transport property, an aromatic hydrocarbon group which may have a substituent is more preferable. When there are a plurality of R ³¹ in the case of being a substituent, they may be different from each other.

The substituent that the aromatic hydrocarbon group having 6 to 30 carbon atoms described above may have, the substituent that the aromatic heterocyclic group having 3 to 30 carbon atoms may have, and the substituent R ³¹ can be selected from the following substituent group Z2.

<Substituent group Z2>
Substituent group Z2 includes an alkyl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an alkoxycarbonyl group, a dialkylamino group, a diarylamino group, an arylalkylamino group, an acyl group, a halogen atom, a haloalkyl group, an alkylthio group, A group consisting of an arylthio group, a silyl group, a siloxy group, a cyano group, an aromatic hydrocarbon group, and an aromatic heterocyclic group. These substituents may contain any structure of linear, branched and cyclic.

More specific examples of the substituent group Z2 include the following structures.
For example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, tert-butyl group, n-hexyl group, cyclohexyl group, dodecyl group, etc. , the number of carbon atoms is usually 1 or more, preferably 4 or more, usually 24 or less, preferably 12 or less, more preferably 8 or less, and still more preferably 6 or less, linear, branched , or a cyclic alkyl group;
An alkoxy group having usually 1 or more carbon atoms, usually 24 or less, preferably 12 or less carbon atoms, such as a methoxy group or an ethoxy group;
For example, an aryloxy group or heteroaryloxy group having usually 4 or more carbon atoms, preferably 5 or more carbon atoms, usually 36 or less, preferably 24 or less carbon atoms such as phenoxy group, naphthoxy group, pyridyloxy group, etc. group;
For example, an alkoxycarbonyl group having usually 2 or more carbon atoms, usually 24 or less, preferably 12 or less, such as a methoxycarbonyl group or an ethoxycarbonyl group;
For example, a dialkylamino group having usually 2 or more carbon atoms, usually 24 or less, preferably 12 or less, such as a dimethylamino group or a diethylamino group;
For example, a diarylamino group having usually 10 or more carbon atoms, preferably 12 or more carbon atoms, usually 36 or less, preferably 24 or less carbon atoms, such as a diphenylamino group or a ditolylamino group;
For example, an arylalkylamino group having usually 7 or more carbon atoms, usually 36 or less, preferably 24 or less, such as a phenylmethylamino group;
For example, an acyl group having usually 2 or more carbon atoms, usually 24 or less, preferably 12 or less, such as an acetyl group or a benzoyl group;
Halogen atoms such as, for example, fluorine atoms and chlorine atoms;
For example, a haloalkyl group having usually 1 or more carbon atoms, usually 12 or less, preferably 6 or less, such as a trifluoromethyl group;
For example, an alkylthio group having usually 1 or more carbon atoms, usually 24 or less, preferably 12 or less, such as a methylthio group or an ethylthio group;
arylthio groups having usually 4 or more, preferably 5 or more, usually 36 or less, preferably 24 or less carbon atoms, such as phenylthio, naphthylthio, and pyridylthio groups;
For example, a silyl group having usually 2 or more carbon atoms, preferably 3 or more carbon atoms, usually 36 or less, preferably 24 or less carbon atoms, such as a trimethylsilyl group or a triphenylsilyl group;
a siloxy group having usually 2 or more carbon atoms, preferably 3 or more carbon atoms, usually 36 or less, preferably 24 or less carbon atoms, such as a trimethylsiloxy group or a triphenylsiloxy group;
cyano group;
aromatic hydrocarbon groups having usually 6 or more carbon atoms, usually 36 or less, preferably 24 or less, such as phenyl group and naphthyl group;
For example, an aromatic heterocyclic group having usually 3 or more, preferably 4 or more, and usually 36 or less, preferably 24 or less carbon atoms such as thienyl group or pyridyl group.

Among the substituent group Z2 described above, an alkyl group, an alkoxy group, a diarylamino group, an aromatic hydrocarbon group, or an aromatic heterocyclic group is preferred. From the viewpoint of charge transport properties, the substituent is preferably an aromatic hydrocarbon group or an aromatic heterocyclic group, more preferably an aromatic hydrocarbon group, and further preferably has no substituent. From the viewpoint of improving solubility, the substituent is preferably an alkyl group or an alkoxy group.

Further, each substituent in the substituent group Z2 may further have a substituent. Examples of these substituents include the same substituents as those described above (substituent group Z2). Each substituent that the substituent group Z2 may have is preferably an alkyl group having 8 or less carbon atoms, an alkoxy group having 8 or less carbon atoms, or a phenyl group, more preferably an alkyl group having 6 or less carbon atoms, It is an alkoxy group having 6 or less carbon atoms or a phenyl group, and each substituent in the substituent group Z2 more preferably does not have a further substituent from the viewpoint of charge transport properties.

<Molecular weight>
The compound represented by the formula (250) is a low-molecular-weight material, and has a molecular weight of preferably 3,000 or less, more preferably 3,000 or less, particularly preferably 2,000 or less, and most preferably 1 , 500 or less. The lower limit of the molecular weight of the compound is usually 300 or higher, preferably 350 or higher, more preferably 400 or higher.

<Specific examples of compounds represented by formula (250)>
The compound represented by formula (250) is not particularly limited, and examples thereof include the following compounds.

The composition for forming a light-emitting layer of the present invention may contain only one type of compound represented by the formula (250), or may contain two or more types thereof.

[Compound: compound represented by formula (260)]
In one embodiment, the composition for forming a light-emitting layer of the present invention contains a compound represented by the following formula (260).

(In the formula (260), each of Ar ²¹ to Ar ³⁵ is independently a hydrogen atom, an optionally substituted phenyl group or an optionally substituted phenyl group, 2 to 10, unbranched or represents a branched and linked monovalent group.)

In the formula (260), Ar ²¹ to Ar ³⁵ are optionally substituted phenyl groups or 2 to 10 optionally substituted phenyl groups are unbranched or branched and linked monovalent The substituent that the phenyl group may have when it is a group is preferably an alkyl group.

<Alkyl group as a substituent>
The alkyl group as a substituent usually has 1 or more and 12 or less carbon atoms, preferably 8 or less, more preferably 6 or less, and more preferably 4 or less, linear, branched or cyclic Alkyl group, specifically methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, tert-butyl group, n-hexyl group , a cyclohexyl group, and a 2-ethylhexyl group.

In formula (260), Ar ²¹ , Ar ²⁵ , Ar ²⁶ , Ar ³⁰ , Ar ³¹ and Ar ³⁵ are preferably hydrogen atoms. Further, at least one of Ar ²² to Ar ²⁴ is a phenyl group which may have a substituent or a group in which 2 to 10 phenyl groups which may have a substituent are unbranched or branched and linked. and/or at least one of Ar ²² to Ar ²⁴ and at least one of Ar ²⁷ to Ar ²⁹ is a phenyl group optionally having the substituent or having the substituent It is preferably an unbranched or branched monovalent group in which 2 to 10 phenyl groups may be linked.

More preferably, structures in which Ar ²² to Ar ²⁴ , Ar ²⁷ to Ar ²⁹ and Ar ³² to Ar ³⁴ are selected from hydrogen atoms, phenyl groups, and the following formulas (261-1) to (261-9) is either
Particularly preferably, Ar ²¹ , Ar ²⁵ , Ar ²⁶ , Ar ³⁰ , Ar ³¹ and Ar ³⁵ are hydrogen atoms, and Ar ²² -Ar ²⁴ , Ar ²⁷ -Ar ²⁹ and Ar ³² -Ar ³⁴ are hydrogen atoms It is an atom, a phenyl group, or a structure selected from the following formulas (261-1) to (261-9).

A structure selected from the following formulas (261-1) to (261-9) may be substituted with an alkyl group as a substituent, for example, an alkyl group having 1 to 12 carbon atoms as a substituent. You can From the viewpoint of improving the solubility, it is preferably substituted with an alkyl group. From the viewpoint of charge transportability and durability during driving of the device, it is preferable not to have a substituent.

By including such a structure in the compound represented by the formula (260), it is considered that the charge transport property in the light-emitting layer can be appropriately adjusted and the luminous efficiency is increased. In addition, it is considered that by including such a structure, the solubility and the durability during driving of the device are excellent.

<Molecular weight>
The compound represented by the formula (260) is a low-molecular-weight material, and has a molecular weight of preferably 3,000 or less, more preferably 2,500 or less, particularly preferably 2,000 or less, and most preferably 1 , 500 or less, usually 300 or more, preferably 350 or more, more preferably 400 or more.

<Specific examples of compounds represented by formula (260)>
The compound represented by formula (260) is not particularly limited, and examples thereof include the following compounds.

The composition for forming a light-emitting layer of the present invention may contain only one compound represented by the formula (260), or may contain two or more compounds.

[Other ingredients]
The composition for organic electroluminescence elements of the present invention may contain various other solvents, if necessary, in addition to the solvent and luminescent material described above. Such other solvents include amides such as N,N-dimethylformamide and N,N-dimethylacetamide, dimethylsulfoxide and the like.

Moreover, the composition for organic electroluminescence elements of the present invention may contain various additives such as a leveling agent and an antifoaming agent.
Furthermore, when laminating two or more layers by a wet film formation method, in order to prevent these layers from becoming compatible, a photocurable resin or a thermosetting resin is used for the purpose of curing and insolubilizing after film formation. can also be included.

[Blending ratio]
Solid content concentration in the composition for organic electroluminescent elements [including the aromatic compound of the present invention, the light-emitting material, the host material other than the aromatic compound of the present invention, and optional components (such as leveling agents) that can be added Concentration of all solids] is usually 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.1% by mass or more, still more preferably 0.5% by mass or more, most preferably 1 % by mass or more, and usually 80% by mass or less, preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, and most preferably 20% by mass or less. When the solid content concentration is within this range, it is easy to form a thin film having a desired film thickness with a uniform thickness, which is preferable.

The preferred compounding ratio of the aromatic compound of the present invention to all the host materials contained in the light-emitting layer is as follows. All host materials refer to all host materials other than the aromatic compound of the present invention and the aromatic compound of the present invention.

The mass ratio of the aromatic compound of the present invention to the mass of all host materials of 100 in the composition for an organic electroluminescent device of the present invention, that is, the mass of the aromatic compound of the present invention to the mass of all host materials in the light-emitting layer of 100 The ratio is 5 or more, preferably 10 or more, more preferably 15 or more, more preferably 20 or more, particularly preferably 25 or more, and 99 or less, preferably 95 or less, further preferably 90 or less, more preferably 80 70 or less is particularly preferable.

Further, the molar ratio of the aromatic compound of the present invention to the total host material in the composition for organic electroluminescent elements of the present invention, that is, the molar ratio of the aromatic compound of the present invention to the total host material in the light-emitting layer is 5 mol. % or more, preferably 10 mol% or more, more preferably 15 mol% or more, 90 mol% or less, preferably 80 mol% or less, further preferably 70 mol% or less, and particularly preferably 60 mol% or less. be.

Further, in the composition for an organic electroluminescent element of the present invention, the mass ratio of the light-emitting material to the mass of all host materials of 100, that is, the mass ratio of the light-emitting material to the mass of all host materials in the light-emitting layer of 100 is 0.1. Above, it is preferably 0.5 or more, more preferably 1 or more, most preferably 2 or more, 100 or less, preferably 60 or less, further preferably 50 or less, most preferably 40 or less. If this ratio falls below the lower limit or exceeds the upper limit, the luminous efficiency may drop significantly.

[Method for preparing composition]
The composition for an organic electroluminescent element of the present invention is a solute comprising the aromatic compound of the present invention, the above-mentioned luminescent material as necessary, and various additives such as a leveling agent and an antifoaming agent that can be added as necessary. is prepared by dissolving in a suitable solvent.

In order to shorten the time required for the dissolving step and to keep the solute concentration in the composition for organic electroluminescent elements of the present invention uniform, the solute is usually dissolved while stirring the liquid. The dissolution step may be performed at room temperature, but if the dissolution rate is slow, the dissolution may be performed by heating. After completion of the dissolving step, a filtering step such as filtering may be performed as necessary.

[Composition properties, physical properties, etc.]
(moisture concentration)
When an organic electroluminescence device is produced by forming layers by a wet film-forming method using the composition of the present invention, if water is present in the composition, the formed film will be contaminated with water, resulting in poor film uniformity. It is preferred that the water content in the compositions of the present invention is as low as possible, as this impairs the In general, organic electroluminescence devices use many materials such as cathodes that are significantly deteriorated by moisture. Possibility of deteriorating the characteristics is considered, which is not preferable.

Specifically, the amount of water contained in the composition of the present invention is usually 1% by mass or less, preferably 0.1% by mass or less, and more preferably 0.01% by mass or less.

As a method for measuring the water concentration in the composition, the method described in Japanese Industrial Standards "Method for measuring water content in chemical products" (JIS K0068: 2001) is preferable, for example, by the Karl Fischer reagent method (JIS K0211-1348). can be analyzed.

(uniformity)
The composition of the present invention is preferably in a uniform liquid state at room temperature in order to improve stability in a wet film formation process, for example, ejection stability from a nozzle in an inkjet film formation method. The uniform liquid state at room temperature means that the composition is a liquid consisting of a uniform phase and does not contain a particle component having a particle size of 0.1 μm or more in the composition.

(physical properties)
When the viscosity of the composition of the present invention is extremely low, for example, excessive liquid film flow in the film formation process tends to cause non-uniformity of the coated surface, nozzle discharge failure in ink jet film formation, and the like. If the viscosity of the composition of the present invention is extremely high, nozzle clogging and the like tend to occur during inkjet film formation.

Therefore, the viscosity of the composition of the present invention at 25° C. is usually 2 mPa·s or more, preferably 3 mPa·s or more, more preferably 5 mPa·s or more, and usually 1000 mPa·s or less, preferably 100 mPa·s or less. , more preferably 50 mPa·s or less.

In addition, when the surface tension of the composition of the present invention is high, the wettability of the film-forming liquid to the substrate is lowered, the leveling property of the liquid film is poor, and the film-forming surface is easily disturbed during drying. may occur.

Therefore, the surface tension of the composition of the present invention at 20°C is usually less than 50 mN/m, preferably less than 40 mN/m.

Furthermore, when the vapor pressure of the composition of the present invention is high, problems such as changes in solute concentration due to evaporation of the solvent may easily occur.

Therefore, the vapor pressure of the composition of the present invention at 25°C is usually 50 mmHg or less, preferably 10 mmHg or less, more preferably 1 mmHg or less.

[Deposition method]
A film forming method using the composition of the present invention, for example, a composition for forming a light-emitting layer, is a wet film forming method. The wet film-forming method is a method in which a composition is applied to form a liquid film, dried to remove the organic solvent, and a film is formed. When the composition of the present invention is a composition for an organic electroluminescence device, the organic layer of the organic electroluminescence device can be formed by a thin film forming method comprising a step of forming a film from the composition by a wet film formation method. . In one aspect, when the composition of the present invention includes a light-emitting material, the light-emitting layer can be formed in this manner. Application methods include spin coating, dip coating, die coating, bar coating, blade coating, roll coating, spray coating, capillary coating, inkjet, nozzle printing, screen printing, and gravure printing. , a method of forming a film by using a wet film forming method such as a flexographic printing method and drying the coating film. Among these film forming methods, the spin coating method, the spray coating method, the inkjet method, the nozzle printing method, and the like are preferable. In the case of manufacturing an organic EL display device having an organic electroluminescence element, an inkjet method or a nozzle printing method is preferable, and an inkjet method is particularly preferable.

Although the drying method is not particularly limited, natural drying, reduced pressure drying, heat drying, or reduced pressure drying while heating can be used as appropriate. Heat drying may be carried out in order to further remove residual organic solvent after natural drying or vacuum drying.

It is preferable that the reduced pressure drying is carried out at a pressure equal to or lower than the vapor pressure of the organic solvent contained in the composition for forming the light-emitting layer.

When heating, the heating method is not particularly limited, but heating with a hot plate, heating in an oven, infrared heating, etc. can be used. The heating time is generally 80° C. or higher, preferably 100° C. or higher, more preferably 110° C. or higher, and preferably 200° C. or lower, more preferably 160° C. or lower.

The heating time is usually 1 minute or longer, preferably 2 minutes or longer, usually 60 minutes or shorter, preferably 30 minutes or shorter, and more preferably 20 minutes or shorter.

[Electron transport layer]
As will be described later, in the organic electroluminescent device, an electron transport layer is formed on the light emitting layer. In the present invention, it is preferable to form a light-emitting layer from the composition of the present invention and form an electron transport layer on the light-emitting layer by a wet film-forming method.

[Composition for Forming Electron Transport Layer]
The composition for forming an electron transport layer in the invention contains at least an electron transport layer material and a solvent. As the solvent for the composition for forming the electron transport layer, an alcohol solvent is preferable. As the electron transport layer material of the electron transport layer-forming composition, an electron transport material soluble in an alcoholic solvent is preferable.

As the alcoholic solvent, an aliphatic alcohol having 3 or more carbon atoms is preferable. Aliphatic alcohols having 6 or more carbon atoms are more preferable because they easily dissolve the electron-transporting material, have a moderately high boiling point, and easily form a flat film.

Preferred aliphatic alcohol solvents include 1-butanol, isobutyl alcohol, 2-hexanol, 1-hexanol, 1-heptanol, 2-methyl-2-pentanol, 4-methyl-3-heptanol and 3-methyl-2-pentanol. , 4-methyl-1-pentanol, 4-heptanol, 1-methoxy-2-propanol, 3-methyl-1-pentanol, 4-octanol, 3-(methylamino)-1-propanol and the like. As a solvent, two or more of these alcohols may be mixed.

[Method for Forming Electron Transport Layer by Wet Film Formation]
As the method for forming the electron transport layer by wet film formation, it is preferable to use the method described in the wet film formation described in the film formation method for the light-emitting layer.

[Organic electroluminescent device]
The organic electroluminescent device of the present invention is an organic electroluminescent device having an anode and a cathode on a substrate and an organic layer between the anode and the cathode, wherein at least one organic layer comprises the aromatic compound of the present invention. including. The layer containing the aromatic compound of the present invention is preferably a light-emitting layer.

As an example of the structure of the organic electroluminescence device of the present invention, FIG. 1 shows a schematic diagram (cross section) of a structural example of the organic electroluminescence device 8 . In FIG. 1, 1 is a substrate, 2 is an anode, 3 is a hole injection layer, 4 is a hole transport layer, 5 is a light emitting layer, 6 is an electron transport layer, and 7 is a cathode.

[substrate]
The substrate 1 serves as a support for the organic electroluminescence element, and is usually made of a quartz or glass plate, a metal plate or metal foil, a plastic film or sheet, or the like. Among these, glass plates and transparent synthetic resin plates such as polyester, polymethacrylate, polycarbonate and polysulfone are preferred. The substrate is preferably made of a material having a high gas barrier property because deterioration of the organic electroluminescence element due to outside air is unlikely to occur. Therefore, especially when using a material having low gas barrier properties such as a synthetic resin substrate, it is preferable to provide a dense silicon oxide film or the like on at least one side of the substrate to improve the gas barrier properties.

[anode]
The anode 2 has the function of injecting holes into the layer on the light-emitting layer 5 side.

Anode 2 is typically made of metals such as aluminum, gold, silver, nickel, palladium, platinum; metal oxides such as indium and/or tin oxide; metal halides such as copper iodide; carbon black and poly(3 -methylthiophene), polypyrrole, and polyaniline.

The formation of the anode 2 is usually carried out by dry methods such as sputtering and vacuum deposition. In addition, when the anode is formed using metal fine particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, conductive polymer fine powder, etc., an appropriate binder resin solution may be used. It can also be formed by dispersing and coating on a substrate. In the case of a conductive polymer, a thin film can be formed directly on a substrate by electrolytic polymerization, or an anode can be formed by coating a conductive polymer on a substrate (Appl. Phys. Lett., 60 2711, 1992).

The anode 2 usually has a single-layer structure, but may have a laminated structure as appropriate. When the anode 2 has a laminated structure, different conductive materials may be laminated on the first layer of the anode.

The thickness of the anode 2 may be determined according to the required transparency and material. When particularly high transparency is required, the thickness is preferably such that the visible light transmittance is 60% or more, and more preferably the thickness is such that the visible light transmittance is 80% or more. The thickness of the anode 2 is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less. On the other hand, when transparency is not required, the thickness of the anode 2 may be arbitrarily set according to the required strength, etc. In this case, the thickness of the anode 2 may be the same as that of the substrate.

When another layer is formed on the surface of the anode 2, the impurity on the anode 2 is removed and its ionization potential is changed by treating with ultraviolet rays/ozone, oxygen plasma, argon plasma, etc. before the film formation. is preferably adjusted to improve the hole injection property.

[Hole injection layer]
A layer that functions to transport holes from the anode 2 side to the light emitting layer 5 side is usually called a hole injection transport layer or a hole transport layer. When there are two or more layers that function to transport holes from the anode 2 side to the light emitting layer 5 side, the layer closer to the anode side may be called the hole injection layer 3 . The hole injection layer 3 is preferably formed in order to enhance the function of transporting holes from the anode 2 to the light emitting layer 5 side. When forming the hole injection layer 3 , the hole injection layer 3 is usually formed on the anode 2 .

The thickness of the hole injection layer 3 is usually 1 nm or more, preferably 5 nm or more, and usually 1000 nm or less, preferably 500 nm or less.

The method for forming the hole injection layer may be a vacuum deposition method or a wet film formation method. From the viewpoint of excellent film-forming properties, it is preferable to form the film by a wet film-forming method.

A general method for forming a hole injection layer will be described below. preferably formed.

The composition for forming a hole injection layer usually contains a hole-transporting compound for a hole-injection layer that becomes the hole-injection layer 3 . In the case of the wet film-forming method, the hole injection layer-forming composition usually further contains a solvent. It is preferable that the composition for forming a hole injection layer has a high hole-transporting property and can efficiently transport the injected holes. For this reason, it is preferable that the hole mobility is large and that impurities that become traps are less likely to occur during manufacture or use. Moreover, it is preferable that it has excellent stability, a small ionization potential, and a high transparency to visible light. In particular, when the hole injection layer is in contact with the light-emitting layer, it is preferable to use a material that does not quench light emitted from the light-emitting layer or that forms an exciplex with the light-emitting layer so as not to lower the light emission efficiency.

The hole-transporting compound for the hole-injection layer is preferably a compound having an ionization potential of 4.5 eV to 6.0 eV from the viewpoint of a charge injection barrier from the anode to the hole-injection layer. Examples of such hole-transporting compounds include aromatic amine-based compounds, phthalocyanine-based compounds, porphyrin-based compounds, oligothiophene-based compounds, polythiophene-based compounds, benzylphenyl-based compounds, and tertiary amines linked with fluorene groups. compounds, hydrazone-based compounds, silazane-based compounds, quinacridone-based compounds, and the like.

Among the exemplified compounds described above, aromatic amine compounds are preferred, and aromatic tertiary amine compounds are particularly preferred, in terms of amorphousness and visible light transparency. Here, the aromatic tertiary amine compound is a compound having an aromatic tertiary amine structure, and includes a compound having a group derived from an aromatic tertiary amine.

The type of the aromatic tertiary amine compound is not particularly limited, but from the viewpoint of easily obtaining uniform light emission due to the surface smoothing effect, a polymer compound having a weight average molecular weight of 1000 or more and 1000000 or less (polymeric compound in which repeating units are linked) ) is preferably used.

When the hole injection layer 3 is formed by a wet film-forming method, a film-forming composition (hole injection Layer-forming composition) is prepared. Then, the hole injection layer 3 is formed by coating the hole injection layer forming composition on the layer (usually the anode) corresponding to the lower layer of the hole injection layer to form a film and drying it.

The concentration of the hole-transporting compound in the hole-injection layer-forming composition is arbitrary as long as it does not significantly impair the effects of the present invention. , a higher value is preferable from the viewpoint that defects are less likely to occur in the hole injection layer. Specifically, it is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, particularly preferably 0.5% by mass or more, and on the other hand, 70% by mass. is preferably 60% by mass or less, and particularly preferably 50% by mass or less.

Examples of solvents include ether-based solvents, ester-based solvents, aromatic hydrocarbon-based solvents, and amide-based solvents.

Examples of ether-based solvents include aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol-1-monomethyl ether acetate (PGMEA), 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, and anisole. , phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole and 2,4-dimethylanisole.

Examples of ester-based solvents include aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, and n-butyl benzoate.

Examples of aromatic hydrocarbon solvents include toluene, xylene, cyclohexylbenzene, 3-isopropylbiphenyl, 1,2,3,4-tetramethylbenzene, 1,4-diisopropylbenzene, cyclohexylbenzene, and methylnaphthalene. be done.

Examples of amide-based solvents include N,N-dimethylformamide and N,N-dimethylacetamide.

In addition to these, dimethyl sulfoxide and the like can also be used.

Formation of the hole injection layer 3 by a wet film-forming method is usually carried out by preparing a composition for forming a hole injection layer and then applying it on a layer corresponding to the lower layer of the hole injection layer 3 (usually the anode 2). It is carried out by coating and forming a film on the surface and drying it.

After forming the hole injection layer 3, the coating film is usually dried by heating, drying under reduced pressure, or the like.

When the hole injection layer 3 is formed by a vacuum deposition method, one or more of the constituent materials of the hole injection layer 3 are usually placed in a crucible placed in a vacuum vessel (two or more materials are placed in separate crucibles), and the inside of the vacuum chamber is evacuated to about 10 ⁻⁴ Pa by a vacuum pump. After that, the crucible is heated (usually each crucible is heated when two or more materials are used) to evaporate while controlling the amount of evaporation of the material in the crucible (when two or more materials are used, (usually independently controlling the amount of evaporation) to form a hole-injecting layer on the anode on the substrate placed facing the crucible. When two or more materials are used, a mixture thereof can be placed in a crucible, heated and evaporated to form the hole injection layer.

The degree of vacuum during vapor deposition ^is not limited as long as ^it does not significantly impair the effects ^of the present invention. 12.0×10 ⁻⁴ Pa) or less. The vapor deposition rate is not limited as long as it does not significantly impair the effects of the present invention, but is usually 0.1 Å/second or more and 5.0 Å/second or less. The film formation temperature during vapor deposition is not limited as long as the effects of the present invention are not significantly impaired, but is preferably 10° C. or higher and 50° C. or lower.

Note that the hole injection layer 3 may be crosslinked in the same manner as the hole transport layer 4 described later.

[Hole transport layer]
The hole transport layer 4 is a layer that functions to transport holes from the anode 2 side to the light emitting layer 5 side. The hole transport layer 4 is not an essential layer in the organic electroluminescent device of the present invention, but it is preferable to form this layer in terms of enhancing the function of transporting holes from the anode 2 to the light emitting layer 5. . When forming the hole transport layer 4 , the hole transport layer 4 is usually formed between the anode 2 and the light emitting layer 5 . Further, when the hole injection layer 3 described above is present, it is formed between the hole injection layer 3 and the light emitting layer 5 .

The film thickness of the hole transport layer 4 is usually 5 nm or more, preferably 10 nm or more, and is usually 300 nm or less, preferably 100 nm or less.

A material that forms the hole transport layer 4 is preferably a material that has a high hole transport property and can efficiently transport the injected holes. Therefore, it is preferable that the ionization potential is low, the transparency to visible light is high, the hole mobility is high, the stability is excellent, and impurities that act as traps are less likely to occur during manufacture or use. In many cases, since the hole transport layer 4 is in contact with the light emitting layer 5, it does not quench the light emitted from the light emitting layer 5 or form an exciplex with the light emitting layer 5 to reduce the efficiency. is preferred.

As the material for such a hole transport layer 4, any material can be used as long as it is a material conventionally used as a constituent material of a hole transport layer. Examples of compounds include those exemplified. Also, arylamine derivatives, fluorene derivatives, spiro derivatives, carbazole derivatives, pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, phthalocyanine derivatives, porphyrin derivatives, silole derivatives, oligothiophene derivatives, condensed polycyclic aromatic group derivatives, metal complexes, and the like.

Also, for example, polyvinylcarbazole derivatives, polyarylamine derivatives, polyvinyltriphenylamine derivatives, polyfluorene derivatives, polyarylene derivatives, polyarylene ether sulfone derivatives containing tetraphenylbenzidine, polyarylene vinylene derivatives, polysiloxane derivatives, polythiophenes. derivatives, poly(p-phenylene vinylene) derivatives and the like. These may be alternating copolymers, random polymers, block polymers or graft copolymers. Also, a polymer having a branched main chain and three or more terminal portions, or a so-called dendrimer may be used.

Among them, polyarylamine derivatives and polyarylene derivatives are preferred.
As the polyarylamine derivative, a polymer containing a repeating unit represented by the following formula (II) is preferred. In particular, a polymer composed of repeating units represented by the following formula (II) is preferable, and in this case, Ar ^a or Ar ^b may be different in each repeating unit.

(In formula (II), Ar ^a and Ar ^b each independently represent an optionally substituted aromatic hydrocarbon group or an optionally substituted aromatic heterocyclic group .)

Examples of polyarylene derivatives include polymers having arylene groups such as optionally substituted aromatic hydrocarbon groups or optionally substituted aromatic heterocyclic groups in their repeating units. .

As the polyarylene derivative, a polymer having repeating units represented by the following formula (III-1) and/or the following formula (III-2) is preferable.

(In formula (III-1), R ^a , R ^b , R ^c and R ^d are each independently an alkyl group, an alkoxy group, a phenylalkyl group, a phenylalkoxy group, a phenyl group, a phenoxy group, an alkylphenyl group, represents an alkoxyphenyl group, an alkylcarbonyl group, an alkoxycarbonyl group or a carboxy group, and t and s each independently represents an integer of 0 to 3. When t or s is 2 or more, a plurality of groups contained in one molecule may be ^the same or different, and adjacent Ra ^or ^Rb may form a ring. ⁾

(In formula (III-2), R ^e and R ^f are each independently synonymous with R ^a , R ^b , R ^c or R ^d in formula (III-1) above. r and u are each independently represents an integer of 0 to 3. When r or u is 2 or more, a plurality of R ^e and R ^f contained in one molecule may be the same or different, and adjacent R ^e or R ^f may form a ring together, and X represents an atom or a group of atoms constituting a 5- or 6-membered ring.)

Specific examples of X include an oxygen atom, an optionally substituted boron atom, an optionally substituted nitrogen atom, an optionally substituted silicon atom, and an optionally substituted an optionally substituted phosphorus atom, an optionally substituted sulfur atom, an optionally substituted carbon atom, or a group formed by combining these atoms.

Further, the polyarylene derivative has a repeating unit represented by the following formula (III-3) in addition to the repeating unit represented by the above formula (III-1) and/or the above formula (III-2). is preferred.

(In formula (III-3), Ar ^c to Ar ⁱ each independently represent an optionally substituted aromatic hydrocarbon group or an optionally substituted aromatic heterocyclic group; and v and w each independently represent 0 or 1.)

Specific examples of the above formulas (III-1) to (III-3) and specific examples of polyarylene derivatives include those described in Japanese Patent Application Laid-Open No. 2008-98619.

When the hole transport layer 4 is formed by a wet film formation method, a composition for forming a hole transport layer is prepared in the same manner as in the formation of the hole injection layer 3, and after wet film formation, heat drying is performed. .

The hole-transporting layer-forming composition contains a solvent in addition to the hole-transporting compound described above. The solvent to be used is the same as that used for the composition for forming the hole injection layer. Further, the film formation conditions, heat drying conditions, etc. are the same as in the case of forming the hole injection layer 3 .

In the case of forming the hole transport layer by vacuum evaporation, the film forming conditions and the like are the same as in the case of forming the hole injection layer 3 described above.

The hole-transporting layer 4 may contain various light-emitting materials, electron-transporting compounds, binder resins, coatability improvers, etc., in addition to the above hole-transporting compounds.

Further, the hole transport layer 4 may be a layer formed by cross-linking a cross-linking compound. The crosslinkable compound is a compound having a crosslinkable group, and forms a network polymer compound by crosslinking.

Examples of crosslinkable groups include groups derived from cyclic ethers such as oxetane and epoxy; groups derived from unsaturated double bonds such as vinyl, trifluorovinyl, styryl, acryl, methacryloyl, and cinnamoyl; Examples thereof include groups derived from cyclobutene.

The crosslinkable compound may be a monomer, oligomer, or polymer. The crosslinkable compound may have only one type, or may have two or more types in any combination and ratio.

A hole-transporting compound having a crosslinkable group is preferably used as the crosslinkable compound. Examples of the hole-transporting compound include those exemplified above, and examples of the cross-linking compound include those in which a cross-linking group is bonded to the main chain or side chain of these hole-transporting compounds. be done. In particular, the crosslinkable group is preferably bonded to the main chain via a linking group such as an alkylene group. In particular, the hole-transporting compound is preferably a polymer containing a repeating unit having a crosslinkable group. Polymers having repeating units linked directly or via a linking group are preferred.

In order to form the hole transport layer 4 by cross-linking the cross-linking compound, a composition for forming a hole transport layer is usually prepared by dissolving or dispersing the cross-linking compound in a solvent, and the film is formed by wet film formation. to cross-link.

The film thickness of the hole transport layer 4 thus formed is usually 5 nm or more, preferably 10 nm or more, and usually 300 nm or less, preferably 100 nm or less.

[Light emitting layer]
The light-emitting layer 5 is a layer that functions to emit light by being excited by recombination of holes injected from the anode 2 and electrons injected from the cathode 7 when an electric field is applied between a pair of electrodes. . The light-emitting layer 5 is a layer formed between the anode 2 and the cathode 7, and the light-emitting layer is formed between the hole-injection layer and the cathode, if there is a hole-injection layer on the anode, and the anode If there is a hole-transport layer on top, it is formed between the hole-transport layer and the cathode.
As described above, the organic electroluminescent device of the invention preferably contains the aromatic compound and the luminescent material of the invention as the luminescent layer.

The film thickness of the light-emitting layer 5 is arbitrary as long as it does not significantly impair the effects of the present invention. However, a thicker film is preferable because defects are less likely to occur in the film. . Therefore, it is preferably 3 nm or more, more preferably 5 nm or more, and on the other hand, it is usually preferably 200 nm or less, more preferably 100 nm or less.

The light-emitting layer 5 contains at least a material having light-emitting properties (light-emitting material), and preferably contains one or more host materials.

[Hole blocking layer]
A hole-blocking layer may be provided between the light-emitting layer 5 and an electron-injecting layer, which will be described later. The hole-blocking layer is a layer laminated on the light-emitting layer 5 so as to be in contact with the interface of the light-emitting layer 5 on the cathode 7 side.

This hole-blocking layer has the role of blocking holes moving from the anode 2 from reaching the cathode 7 and the role of efficiently transporting electrons injected from the cathode 7 toward the light-emitting layer 5. have. The physical properties required for the material constituting the hole blocking layer include high electron mobility and low hole mobility, a large energy gap (difference between HOMO and LUMO), and an excited triplet level (T ₁ ). is high.

Examples of materials for the hole blocking layer that satisfy these conditions include bis(2-methyl-8-quinolinolato)(phenolato)aluminum, bis(2-methyl-8-quinolinolato)(triphenylsilanolate)aluminum, and the like. mixed ligand complexes, bis (2-methyl-8-quinolato) aluminum-μ-oxo-bis- (2-methyl-8-quinolato) aluminum binuclear metal complexes such as metal complexes, distyrylbiphenyl derivatives and the like Styryl compounds (JP-A-11-242996), triazole derivatives such as 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole ( JP-A-7-41759), phenanthroline derivatives such as bathocuproine (JP-A-10-79297), and the like. Furthermore, the compound having at least one pyridine ring substituted at the 2,4,6 positions described in WO 2005/022962 is also preferable as a material for the hole blocking layer.

The method for forming the hole-blocking layer is not limited, but from the viewpoint of efficiently using the same wet process when the light-emitting layer is formed by wet film formation, wet film formation is preferred by vapor deposition or other methods. method is particularly preferred.

The thickness of the hole-blocking layer is arbitrary as long as it does not significantly impair the effects of the present invention, but it is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less. .

[Electron transport layer]
The electron transport layer 6 is provided between the light emitting layer 5 and the cathode 7 for the purpose of further improving the current efficiency of the device.

The electron transport layer 6 is made of a compound that can efficiently transport electrons injected from the cathode 7 toward the light emitting layer 5 between electrodes to which an electric field is applied. The electron-transporting compound used in the electron-transporting layer 6 is a compound that has high electron injection efficiency from the cathode 7, high electron mobility, and can efficiently transport the injected electrons. is required.

Specific examples of the electron-transporting compound used in the electron-transporting layer include metal complexes such as an aluminum complex of 8-hydroxyquinoline (Japanese Patent Application Laid-Open No. 59-194393) and 10-hydroxybenzo[h]quinoline. metal complexes, oxadiazole derivatives, distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, trisbenzimidazolylbenzene (US Pat. No. 5,645,948 specification), quinoxaline compounds (Japanese Patent Laid-Open No. 6-207169), phenanthroline derivatives (Japanese Patent Laid-Open No. 5-331459), 2-tert-butyl-9,10-N,N'-dicyanoanthraquinonedi amine, n-type hydrogenated amorphous silicon carbide, n-type zinc sulfide, n-type zinc selenide, and the like.

The film thickness of the electron transport layer 6 is usually 1 nm or more, preferably 5 nm or more, and is usually 300 nm or less, preferably 100 nm or less.

The electron-transporting layer 6 is formed by laminating on the hole-blocking layer by a wet film-forming method or a vacuum deposition method in the same manner as described above. A vacuum deposition method is usually used. In the invention, as described above, the electron transport layer can be formed on the light-emitting layer containing the aromatic compound of the invention by a wet film-forming method.

[Electron injection layer]
The electron injection layer may be provided to efficiently inject electrons injected from the cathode 7 into the electron transport layer 6 or the light emitting layer 5 .

In order to efficiently perform electron injection, it is preferable that the material forming the electron injection layer be a metal with a low work function. Examples thereof include alkali metals such as sodium and cesium, alkaline earth metals such as barium and calcium, and the like. The film thickness is preferably 0.1 nm or more and 5 nm or less.

Furthermore, an organic electron-transporting material typified by a nitrogen-containing heterocyclic compound such as bathophenanthroline or a metal complex such as an aluminum complex of 8-hydroxyquinoline is doped with an alkali metal such as sodium, potassium, cesium, lithium or rubidium ( JP-A-10-270171, JP-A-2002-100478, JP-A-2002-100482, etc.) also improves electron injection and transport properties and achieves excellent film quality. It is preferable because it enables

The thickness of the electron injection layer is usually 5 nm or more, preferably 10 nm or more, and usually 200 nm or less, preferably 100 nm or less.

The electron injection layer is formed by laminating the light emitting layer 5 or the hole blocking layer or the electron transport layer 6 thereon by a wet film forming method or a vacuum deposition method.
The details of the wet film formation method are the same as those of the light-emitting layer described above.

In some cases, the hole-blocking layer, electron-transporting layer, and electron-injecting layer are formed into a single layer by co-doping the electron-transporting material and the lithium complex.

[cathode]
The cathode 7 plays a role of injecting electrons into a layer (an electron injection layer, a light-emitting layer, or the like) on the light-emitting layer 5 side.

As the material of the cathode 7, it is possible to use the material used for the anode 2, but in terms of efficient electron injection, it is preferable to use a metal with a low work function, such as tin or magnesium. , indium, calcium, aluminum, and silver, or alloys thereof. Specific examples include low work function alloy electrodes such as magnesium-silver alloys, magnesium-indium alloys, and aluminum-lithium alloys.

From the viewpoint of the stability of the organic electroluminescent device, it is preferable to protect the cathode made of a metal with a low work function by stacking a metal layer that has a high work function and is stable against the atmosphere on the cathode. Metals to be laminated include, for example, metals such as aluminum, silver, copper, nickel, chromium, gold, and platinum.

The film thickness of the cathode is usually the same as that of the anode.

[Other layers]
The organic electroluminescence device of the present invention may further have other layers as long as they do not significantly impair the effects of the present invention. That is, it may have any of the other layers described above between the anode and cathode.

[Other device configurations]
The organic electroluminescence device of the present invention has a structure opposite to that described above. It is also possible to laminate the injection layer and the anode in this order.

When the organic electroluminescent element of the present invention is applied to an organic electroluminescent device, it may be used as a single organic electroluminescent element or may be used in a configuration in which a plurality of organic electroluminescent elements are arranged in an array. A configuration in which anodes and cathodes are arranged in an XY matrix may be used.

<Display device>
The display device (organic EL display device, organic electroluminescent element display device) of the present invention comprises the organic electroluminescent element of the present invention. The type and structure of the organic EL display device of the present invention are not particularly limited, and the organic electroluminescence device of the present invention can be assembled according to a conventional method.

For example, the organic EL display device of the present invention can be manufactured by the method described in "Organic EL Display" (Ohmsha, August 20, 2004, by Shizuo Tokito, Chihaya Adachi, and Hideyuki Murata). can be formed.

<Lighting device>
The lighting device (organic EL lighting, organic electroluminescent element lighting) of the present invention comprises the organic electroluminescent element of the present invention. The type and structure of the organic EL lighting of the present invention are not particularly limited, and the organic electroluminescence device of the present invention can be assembled according to a conventional method.

[Method for producing organic electroluminescent device]
The present invention also relates to a method for manufacturing an organic electroluminescent device having an anode and a cathode on a substrate and an organic layer between the anode and the cathode. The method for producing an organic electroluminescent device of the present invention includes a step of forming an organic layer including a light-emitting layer and an electron transport layer, and forming the light-emitting layer by a wet film-forming method using the composition for forming a light-emitting layer of the present invention. and forming an electron-transporting layer by a wet film-forming method using an electron-transporting layer composition containing an electron-transporting material and a solvent.

In the method for producing an organic electroluminescent device, preferred aspects of each layer constituting the organic electroluminescent device, the composition for forming the light-emitting layer and the composition for forming the electron-transporting layer, and the method for forming a film by a wet film-forming method are as described above. is. For example, the solvent contained in the electron-transporting layer composition used in the method for producing an organic electroluminescent device is preferably an alcohol-based solvent.

Although the present invention will be described in more detail below with reference to examples, the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

Hereinafter, the present invention will be described more specifically by showing examples. However, the present invention is not limited to the following examples, and the present invention can be arbitrarily modified without departing from the scope of the invention. Synthesis of each compound was performed by the method described in International Publication No. 2019/177175.

<Synthesis of intermediates>
[Synthesis of compound 3]

Under a nitrogen stream, compound 1 (20.0 g, 46.3 mmol), compound 2 (21.5 g, 46.3 mmol), 2M potassium phosphate aqueous solution (70.0 g, 139.0 mmol), toluene (140 ml), ethanol. (70 ml) was charged into a flask, the inside of the system was sufficiently replaced with nitrogen, and the mixture was heated to 60°C.

Tetrakis(triphenylphosphine)palladium(0) (1.6 g, 1.39 mmol) was added, and the mixture was heated to reflux at 85°C and stirred for 2 hours. Water was added to the reaction solution, and extraction was performed with toluene. The organic layer was dried over anhydrous magnesium sulfate and crudely purified with activated clay. The crude product was purified by column chromatography (developer: hexane/methylene chloride=3:1) to obtain compound 3 (19.6 g, yield 61%).

[Synthesis of Compound 4]

Under a nitrogen stream, 250 ml of dimethylsulfoxide, compound 3 (19.6 g, 28.4 mmol), bis(pinacolato)diboron (8.7 g, 34.1 mmol), potassium acetate (8.4 g, 85.2 mmol) were placed in a 500 ml flask. ) was added and stirred at 60° C. for 30 minutes. After that, 1,1′-bis(diphenylphosphino)ferrocene-palladium(II) dichloride-dichloromethane [PdCl ₂ (dppf)CH ₂ Cl ₂ ] (1.2 g, 1.42 mmol) was added and the mixture was stirred at 90° C. for 4 hours. Reacted for 5 hours.

Pure water was added dropwise at room temperature, the reaction solution was filtered under reduced pressure, the filtrate was extracted with toluene, dried over anhydrous magnesium sulfate, and purified with activated clay. Compound 4 (19.2 g, 92% yield) was obtained.

[Synthesis of Compound 5]

Then, compound 4 (19.0 g, 25.8 mmol), commercially available 3′-bromo-3-iodo-[1,1′-biphenyl (9.3 g, 25.8 mmol), potassium phosphate (2 M aqueous solution, 39 ml), toluene (80 ml), and ethanol (40 ml) were introduced into a flask, and the inside of the system was sufficiently replaced with nitrogen and heated to 60°C. Bis(triphenylphosphine)palladium(II) dichloride (91 mg, 0.13 mmol) was added and stirred at 60° C. for 6 hours. Water was added to the reaction solution, and extraction was performed with toluene. The organic layer was dried over anhydrous magnesium sulfate and crudely purified with activated clay. The crude product was purified by column chromatography (developer: hexane:methylene chloride=700:300) to obtain compound 5 (15.1 g, yield 69%).

[Synthesis of compound 6]

Under a nitrogen stream, 100 ml of deoxygenated dimethyl sulfoxide, compound 5 (21.7 g, 25.7 mmol), bis(pinacolato)diboron (9.8 g, 38.6 mmol), potassium acetate (7.6 g, 77.1 mmol) was added and stirred at 60° C. for 30 minutes. After that, 1,1′-bis(diphenylphosphino)ferrocene-palladium(II) dichloride-dichloromethane [PdCl ₂ (dppf)CH ₂ Cl ₂ ] (2.1 g, 2.57 mmol) was added and the mixture was stirred at 95° C. for 7.5 hours. Reacted for 5 hours.

Pure water was added dropwise at room temperature, the reaction solution was filtered under reduced pressure, the filtrate was extracted with toluene, dried over anhydrous magnesium sulfate, and purified with activated clay. Compound 6 (24.2 g, 99% yield) was obtained.

[Synthesis of Compound 8]

Compound 7 (7.1 g, 21.4 mmol), 1-bromo-3-fluorobenzene (25.0 g, 142.9 mmol), and cesium carbonate (41.9 g, 128.5 mmol) were placed in a 300 ml flask under a nitrogen stream. 100 ml of N,N-dimethylformamide was added, and the mixture was heated and stirred at 150° C. for 24 hours. After that, 120 ml of deionized water was added at room temperature and stirred for 10 minutes. The precipitate was filtered under reduced pressure, and the filtered product was added to a mixed solution of 50 ml of ethyl acetate and 50 ml of ethanol, heated with stirring at 50° C., and filtered under reduced pressure. This operation was repeated twice to obtain compound 8 (11.6 g, yield 85%).

[Synthesis of Compound 9]

Compound 7 (2.0 g, 6.0 mmol) and commercially available 3′-bromo-3-iodo-[1,1′-biphenyl (6.5 g, 18.1 mmol) were placed in a 100 ml flask at room temperature under a nitrogen stream. , potassium carbonate (5.0 g, 36.1 mmol) and 20 ml of tetraethylene glycol dimethyl ether were added, nitrogen was bubbled for 10 minutes, copper powder (1.2 g, 18.1 mmol) was added at once, and the reaction temperature was 7.5 at 170°C. Heated and stirred for hours. After that, 40 ml of methylene chloride was added to the reaction system at room temperature, filtered through celite under reduced pressure, 40 ml of ethanol was added to the filtrate, the precipitate was filtered under reduced pressure, and the filtrate was subjected to column chromatography (developing solution: hexane: chloride). methylene=3:1) to give compound 9 (2.8 g, yield 59%).

[Synthesis of Compound 10]

Under a nitrogen stream, 45 ml of deoxygenated dimethyl sulfoxide, compound 9 (2.8 g, 3.5 mmol), bis(pinacolato)diboron (2.7 g, 10.5 mmol), potassium acetate (2.1 g, 21.4 mol) was added and stirred at 60° C. for 30 minutes. After that, 1,1′-bis(diphenylphosphino)ferrocene-palladium(II) dichloride-dichloromethane [PdCl ₂ (dppf)CH ₂ Cl ₂ ] (0.6 g, 0.73 mmol) was added and stirred at 95° C. for 10 hours. reacted.

Pure water was added dropwise at room temperature, and the reaction solution was filtered under reduced pressure. The filtrate was extracted with 50 ml of methylene chloride, dried over anhydrous magnesium sulfate, and purified with activated clay. Compound 10 (0.94 g, 30% yield) was obtained.

[Synthesis Example 1: Synthesis of compound (H-1)]

Under a nitrogen stream, compound 6 (22.2 g, 23.1 mmol), compound 8 (6.7 g, 10.5 mmol), 2 M potassium phosphate aqueous solution (32.0 g, 63 mmol), toluene (80 ml), ethanol (32 ml) ) was placed in a flask, the system was sufficiently purged with nitrogen, and heated to 60°C.

Tetrakis(triphenylphosphine)palladium(0) (0.73 g, 0.63 mmol) was added, and the mixture was heated to reflux at 100°C and stirred for 3 hours. Water was added to the reaction solution, and extraction was performed with toluene. The organic layer was dried over anhydrous magnesium sulfate and crudely purified with activated clay. The crude product was purified by column chromatography (developer: hexane/methylene chloride=2:1) to obtain compound (H-1) (16.2 g, yield 83%).

[Synthesis Example 2: Synthesis of Compound (H-2)]

Under a nitrogen stream, compound 5 (2.6 g, 2.8 mmol), compound 10 (0.94 g, 1.18 mmol), 2 M potassium phosphate aqueous solution (3.5 ml), toluene (10 ml), ethanol (5 ml) The mixture was placed in a flask, the inside of the system was sufficiently replaced with nitrogen, and the mixture was heated to 60°C.

Tetrakis(triphenylphosphine)palladium(0) (0.1 g, 0.084 mmol) was added, and the mixture was heated to reflux at 100°C and stirred for 4.5 hours. Water was added to the reaction solution, and extraction was performed with toluene. The organic layer was dried over anhydrous magnesium sulfate and crudely purified with activated clay. The crude product was purified by column chromatography (developer: hexane/methylene chloride=650:350) to obtain compound (H-2) (1.4 g, yield 55%).

<Evaluation of each compound>
The glass transition temperature (Tg) of each compound was evaluated by differential scanning calorimetry (DSC). The ionization potential (Ip) of each compound was evaluated by photoelectron spectroscopy. The electron affinity (Ea) of each compound was calculated by subtracting Ip from the bandgap (Eg) calculated from the absorption edge of the absorption spectrum.
Table 1 shows the results.

The comparative compound 1 used was represented by the following formula (C-1), and the comparative compound 2 was represented by the following formula (C-2).

From the results in Table 1, it can be confirmed that the glass transition temperature (Tg) of the molecule is further increased by increasing the molecular weight, and the energy cap (Eg) of the molecule is further widened, leading to higher efficiency of the organic electroluminescent device. It turned out to be promising.

Solubility in cyclohexylbenzene (CHB) is measured by preparing a cyclohexylbenzene solution of about 1 to 2 mL (concentration of each compound: 1.0% by mass, 4.0% by mass and 8.0% by mass), It was judged whether or not each compound was dissolved in the solution.
Table 2 shows the results. "O" in the columns "1.0% by mass CHB solution", "4.0% by mass CHB solution" and "8.0% by mass CHB solution" in Table 2 indicates that the compound was dissolved in the solution. and "x" means that the compound did not dissolve in the solution. "○" in the column "Precipitation test of 8.0% by mass CHB solution" in Table 2 indicates that the compound did not precipitate from the solution after one day after preparing the 8.0% by mass CHB solution. "x" means that the compound was precipitated from the solution one week after the 8.0% by mass CHB solution was prepared.

The comparative compound 1, the comparative compound 2, or the comparative compound 3 used the following formula (C-3), and the comparative compound 4 used the following formula (C-4).

From the results in Table 2, the degree of freedom of the packing site of the molecule is reduced by having a phenylene structure that is characteristic of the compound with a large molecular weight of the present invention, and even after one week, it does not precipitate from the 8.0% by mass CHB solution. was found to have excellent solubility in solvents.

Next, the solvent resistance of the compound after film formation was evaluated as follows.
First, a solution was prepared by dissolving 1.5% by mass of a compound to be tested in toluene. In a nitrogen glove box, this solution was dropped onto a glass substrate, spin-coated, and dried on a hot plate at 100° C. for 10 minutes to form a compound film to be tested.

Next, the substrate on which the compound film was formed was set in a spin coater, 150 μl of the test solvent was dropped onto the substrate, and after dropping, the substrate was allowed to stand for 60 seconds to conduct a solvent resistance test.

After that, the substrate was rotated at 1500 rpm for 30 seconds and then at 4000 rpm for 30 seconds to spin out the dropped solvent. This substrate was dried on a hot plate at 120° C. for 10 minutes. The film thickness before and after the solvent resistance test was measured using a stylus profilometer, and the film thicknesses before and after the test were compared.

A solvent resistance test was performed using the compound (H-1) of the present invention, which did not precipitate from the 8.0% by mass CHB solution even after one week, and the comparative compounds 1 and 3. 1-butanol and 1-heptanol were used as test solvents.

[Example 1]
A film was formed using the compound (H-1) of the present invention as a compound to be tested, and a solvent resistance test was conducted using 1-butanol as a test solvent.

[Comparative Example 1]
A film was formed using comparative compound 3 as the test target compound, and a solvent resistance test was conducted using 1-butanol as the test solvent.

[Comparative Example 2]
A film was formed using Comparative Compound 1 as the test target compound, and a solvent resistance test was conducted using 1-butanol as the test solvent.

[Example 2]
A film was formed using the compound (H-1) of the present invention as a compound to be tested, and a solvent resistance test was conducted using 1-heptanol as a test solvent.

[Comparative Example 3]
A film was formed using Comparative Compound 3 as the test target compound, and a solvent resistance test was conducted using 1-heptanol as the test solvent.

[Comparative Example 4]
A film was formed using Comparative Compound 1 as the test target compound, and a solvent resistance test was conducted using 1-heptanol as the test solvent.

Table 3 shows the results of the solvent resistance test.

From the results in Table 3, it can be seen that the aromatic compound of the present invention exhibits high solvent resistance to alcohol solvents.

<Preparation of organic electroluminescent device>
[Example 3]
An organic electroluminescence device was produced by the following method.
An indium tin oxide (ITO) transparent conductive film deposited on a glass substrate to a thickness of 50 nm (manufactured by Geomatec, a sputter-deposited product) was subjected to a 2 mm-wide stripe using ordinary photolithography and etching with hydrochloric acid. was patterned to form an anode. The substrate on which the ITO pattern is formed in this manner is washed with ultrasonic waves using an aqueous solution of surfactant, washed with ultrapure water, ultrasonically washed with ultrapure water, and washed with ultrapure water in this order, and then dried with compressed air. , and finally performed ultraviolet ozone cleaning.

As a composition for forming a hole injection layer, 3.0% by mass of a hole-transporting polymer compound having a repeating structure of the following formula (P-1) and 0.6% by mass of an electron-accepting compound (HI-1) was dissolved in ethyl benzoate to prepare a composition.

This solution was spin-coated on the substrate in the atmosphere and dried on a hot plate in the atmosphere at 240° C. for 30 minutes to form a uniform thin film with a thickness of 40 nm, which was used as a hole injection layer.
Next, a charge-transporting polymer compound having the following structural formula (HT-1) was dissolved in 1,3,5-trimethylbenzene to prepare a 2.0% by mass solution.
This solution was spin-coated on the substrate on which the hole injection layer was coated in a nitrogen glove box, and dried on a hot plate in the nitrogen glove box at 230° C. for 30 minutes to form a uniform thin film with a thickness of 40 nm. was formed to form a hole transport layer.

Subsequently, as materials for the light-emitting layer, 1.56% by mass of the compound (M-1) having the following structure, 3.64% by mass of the compound (H-1) of the present invention, and the compound (D -1) was dissolved in cyclohexylbenzene at a concentration of 1.56% by mass to prepare a composition for forming a light-emitting layer. The compounding ratio of compound (M-1) and compound (H-1) was 30:70 in mass ratio and 50:50 in molar ratio.

This solution was spin-coated in a nitrogen glove box onto the substrate on which the hole transport layer had been applied and dried on a hot plate in the nitrogen glove box at 120° C. for 20 minutes to form a uniform thin film with a thickness of 40 nm. was formed to form a light-emitting layer.
The substrate on which up to the light-emitting layer was formed was placed in a vacuum deposition apparatus, and the inside of the apparatus was evacuated to 2×10 ⁻⁴ Pa or less.
Next, the following structural formula (ET-1) and 8-hydroxyquinolinolatritium were co-deposited on the light-emitting layer at a film thickness ratio of 2:3 by a vacuum vapor deposition method to form an electron-transporting layer having a film thickness of 30 nm. formed.

Subsequently, a striped shadow mask with a width of 2 mm was adhered to the substrate so as to be orthogonal to the ITO stripes of the anode as a mask for cathode evaporation, and aluminum was heated with a molybdenum boat to form an aluminum layer with a thickness of 80 nm. formed to form the cathode. As described above, an organic electroluminescence device having a light-emitting area of 2 mm×2 mm was obtained.

[Comparative Example 5]
The light emitting layer has a concentration of 3.12% by mass of the compound (M-1), 2.08% by mass of the compound having the structure of the following formula (C-1), and 1.56% by mass of the compound (D-1). An organic electroluminescence device was produced in the same manner as in Example 3, except that the composition for forming a light-emitting layer dissolved in cyclohexylbenzene was used. The compounding ratio of compound (M-1) and compound (C-3) was 53:47 in molar ratio, which was almost the same as in Example 3.

[Comparative Example 6]
The light-emitting layer was prepared by dissolving the compound (M-1) at a concentration of 1.56% by mass, the compound (C-1) at a concentration of 3.64% by mass, and the compound (D-1) at a concentration of 1.56% by mass in cyclohexylbenzene. An organic electroluminescence device was produced in the same manner as in Example 3, except that the composition for forming a light-emitting layer was used. The compounding ratio of compound (M-1) and compound (C-3) was 30:70 in mass ratio, which was the same as in Example 3.

[Evaluation of Organic Electroluminescent Device]
The external quantum efficiency (%) was measured when the organic electroluminescent devices obtained in Example 3, Comparative Example 5 and Comparative Example 6 were caused to emit light at 1,000 cd/m ² . Table 4 shows the relative external quantum efficiency (“relative EQE”) when the external quantum efficiency of Comparative Example 5 is set to 100.

From the results in Table 4, it was found that the performance of the organic electroluminescence device using the aromatic compound of the present invention was improved.

This application is based on a Japanese patent application (Japanese Patent Application No. 2021-094591) filed on June 4, 2021, the contents of which are incorporated herein by reference.

The present invention has excellent heat resistance, excellent heat resistance, high solubility, difficulty in forming an aggregation structure of molecules, easy adjustment of charge balance, and excellent durability against alcohol solvents after film formation. It is possible to provide an aromatic compound having The present invention also provides an organic electroluminescence device containing the aromatic compound, a display device and a lighting device containing the organic electroluminescence device, a composition containing the compound and a solvent, a method for forming a thin film, and production of the organic electroluminescence device. can provide a method.

REFERENCE SIGNS LIST 1 substrate 2 anode 3 hole injection layer 4 hole transport layer 5 light emitting layer 6 electron transport layer 7 cathode 8 organic electroluminescence element

Claims

An aromatic compound represented by the following formula (1).

(In formula (1), G 1 and G 2 each independently represent an aromatic hydrocarbon group, X 1 to X 7 are each independently CR 1A or a nitrogen atom, and R 1A appears each independently represents a hydrogen atom, a deuterium atom, CN, or an optionally substituted aromatic hydrocarbon group having from 6 to 30 carbon atoms, G is a hydrogen atom, a deuterium atom , CN, an optionally substituted aromatic hydrocarbon group having 6 to 30 carbon atoms, or formula (2).

In formula (2), G3 represents an aromatic hydrocarbon group. X 15 to X 21 are each independently CR 1B or a nitrogen atom, and each occurrence of R 1B may independently be a hydrogen atom, a deuterium atom, CN, or have a substituent It represents an aromatic hydrocarbon group having 6 to 30 carbon atoms.
When G is a hydrogen atom, a deuterium atom, CN, or an optionally substituted aromatic hydrocarbon group having 6 to 30 carbon atoms, at least one of G 1 and G 2 has 54 to 240, and when G has the above formula (2), at least one of G 1 , G 2 and G 3 has 28 to 240 carbon atoms.
* represents the binding site)
The aromatic compound according to claim 1, represented by the following formula (1-A).

(In formula (1-A), G A represents a hydrogen atom, a deuterium atom, CN, or an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent. X 1 to X 7 , G 1 and G 2 are as defined for formula (1) above.)
The aromatic compound according to claim 1, represented by the following formula (1-B).

(In formula (1-B), X 8 to X 14 are defined in the same manner as X 1 to X 7 in formula (1) above. X 15 to X 21 are as defined in formula (2) above. and G 1 , G 2 and G 3 are as defined for formulas (1) and (2) above.)
At least one of G 1 or G 2 is the following formula (17-2), the following formula (20-2), the following formula (13), the following formula (14), the following formula (15), or the following formula (16) 3. The aromatic compound according to claim 2, comprising a partial structure represented by.
At least one of G 1 to G 3 is the following formula (17-2), the following formula (20-2), the following formula (13), the following formula (14), the following formula (15), or the following formula (16) The aromatic compound according to claim 3, comprising a partial structure represented by.
The substituents that the aromatic hydrocarbon group having 6 to 30 carbon atoms of R 1A and GA may have are each independently an aromatic hydrocarbon group having 6 to 30 carbon atoms.
The aromatic compound according to claim 2.
The substituents that the aromatic hydrocarbon group having 6 to 30 carbon atoms of R 1A and R 1B may have are each independently an aromatic hydrocarbon group having 6 to 30 carbon atoms.
The aromatic compound according to claim 3.
An organic electroluminescence device having an anode and a cathode on a substrate and an organic layer between the anode and the cathode, wherein at least one of the organic layers is the An organic electroluminescent device comprising the aromatic compound described.
The organic electroluminescent device according to claim 8, wherein the layer containing the aromatic compound is a light-emitting layer.
A display device comprising the organic electroluminescence device according to claim 8 or 9.
A lighting device comprising the organic electroluminescent device according to claim 8 or 9.
A composition for forming a light-emitting layer of an organic electroluminescent device, containing the aromatic compound according to any one of claims 1 to 7 and a solvent.
The composition according to claim 12, further comprising a phosphorescent material and a charge transport material.
14. The composition according to claim 13, wherein the charge transport material contains at least one of a compound represented by the following formula (250) and a compound represented by the following formula (260).

(In formula (250),
W each independently represents CH or N, at least one W is N,
Xa 1 , Ya 1 , and Za 1 are each independently an optionally substituted divalent aromatic hydrocarbon group having 6 to 30 carbon atoms, or an optionally substituted carbon represents a divalent aromatic heterocyclic group of numbers 3 to 30,
Xa 2 , Ya 2 and Za 2 are each independently a hydrogen atom, a monovalent aromatic hydrocarbon group optionally having 6 to 30 carbon atoms, or optionally having a substituent represents a good monovalent aromatic heterocyclic group having 3 to 30 carbon atoms,
g11, h11, and j11 each independently represents an integer of 0 to 6,
at least one of g11, h11, and j11 is an integer of 1 or more;
When g11 is 2 or more, multiple Xa 1 may be the same or different,
When h11 is 2 or more, multiple Ya 1 may be the same or different,
When g11 is 2 or more, multiple Za 1 may be the same or different,
R 31 represents a hydrogen atom or a substituent, the four R 31 may be the same or different,
However, when g11, h11 or j11 is 0, the corresponding Xa 2 , Ya 2 and Za 2 are not hydrogen atoms. )

(In the formula (260), each of Ar 21 to Ar 35 is independently a hydrogen atom, an optionally substituted phenyl group or an optionally substituted phenyl group, 2 to 10, unbranched or represents a branched and linked monovalent group.)
The composition according to claim 14, wherein at least two of W in said formula (250) are N.
The composition according to claim 14, wherein all W in the formula (250) are N.
In the formula (260), Ar 21 , Ar 25 , Ar 26 , Ar 30 , Ar 31 and Ar 35 are hydrogen atoms,
Ar 22 to Ar 24 , Ar 27 to Ar 29 , and Ar 32 to Ar 34 are hydrogen atoms, phenyl groups, or structures selected from the following formulas (261-1) to (261-9). 15. The composition according to claim 14, wherein these structures may have an alkyl group having 1 to 12 carbon atoms as a substituent.
A method for forming a thin film, comprising the step of forming a film from the composition according to any one of claims 12 to 17 by a wet film forming method.
A method for producing an organic electroluminescence device having an anode and a cathode on a substrate and an organic layer between the anode and the cathode, the method comprising:
the organic layer comprises a light-emitting layer and an electron-transporting layer;
forming the light emitting layer by a wet film-forming method using the composition according to any one of claims 12 to 17; and forming the electron transport layer for an electron transport layer containing an electron transport material and a solvent. A method for producing an organic electroluminescence device, comprising a step of forming the composition by a wet film-forming method.
The method for producing an organic electroluminescence device according to claim 19, wherein the solvent contained in the electron transport layer composition is an alcohol solvent.