WO2022255428A1

WO2022255428A1 - Aromatic compound, organic electroluminescent element, composition, and method for producing organic electroluminescent element

Info

Publication number: WO2022255428A1
Application number: PCT/JP2022/022397
Authority: WO
Inventors: 司長谷川; 一毅岡部; 延軍李; 大輔弘
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: JPWO2022255428A1; CN117480156A; KR20240016969A; TW202313930A

Abstract

The present invention addresses the problem of providing an aromatic compound which has excellent heat resistance, excellent solubility, and excellent electron-transporting properties and which gives thin films having excellent resistance to alcohol solvents. The present invention relates to: an aromatic compound represented by formula (1); an organic electroluminescent element including an organic layer which comprises the aromatic compound as a material for organic electroluminescent elements; a composition for organic electroluminescent elements which comprises the aromatic compound and a solvent; and a method for producing the organic electroluminescent element. (In formula (1), G1, G2, and G3 respectively have the same meanings as defined in the specification.)

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.

In recent years, as thin-film electroluminescent elements, instead of those using inorganic materials, organic electroluminescent elements using organic thin films have been developed. An organic electroluminescent device (OLED) typically has a hole-injection layer, a hole-transport layer, an organic light-emitting layer, an electron-transport layer, etc. between an anode and a cathode. Materials suitable for each of these layers are being developed, and the development of red, green, and blue emission colors is progressing. In addition, research is being conducted on coating-type OLEDs, which are more efficient in material utilization than conventional evaporation-type OLEDs and can reduce manufacturing costs.

For coating-type OLEDs, there is a demand for longer life of organic electroluminescent elements and driving with lower power consumption. Various factors can be considered to affect the lifetime and power consumption improvement of an organic electroluminescent device. For example, the thermal durability and crystallinity of the materials that make up the organic electroluminescent device have a large effect on the lifetime. is considered a thing.

In addition, in order to manufacture organic electroluminescent elements by the wet film-forming method, all the materials used must be able to dissolve in organic solvents and be used as ink. If the material to be used has poor solubility, the material may deteriorate before use because an operation such as heating for a long period of time is required. Furthermore, if the uniform state cannot be maintained for a long time in a solution state, the material will precipitate out of the solution, making it impossible to form a film using an inkjet device or the like. Materials used in the wet film-forming method are required to have solubility in two senses: rapid dissolution in an organic solvent and maintenance of a homogeneous state without precipitating after dissolution.

Patent Document 1 reports an OLED material using an aromatic compound containing a triazine structure, such as the following compound (C-1), as a charge transport material for a phosphorescent compound.

Patent Document 2 reports an OLED material using an aromatic compound containing a triazine and a spirobifluorene structure, such as compounds (C-2) to (C-4) below, as a material for the life improving layer.

WO2012/137958 U.S. Pat. No. 9,960,363

However, the above compound (C-1) has a glass transition temperature as low as 93°C and does not have sufficient heat resistance. When the above compounds (C-2) to (C-4) are used as the charge transport material of the light-emitting layer, the electron mobility is insufficient and the device efficiency and device life are low. Furthermore, the durability to alcohol solvents for laminating a thin film by a wet film forming method using an alcohol solvent on the thin film formed from the above compounds (C-1) to (C-4) is not sufficient. .

The present invention has been made in view of the above-mentioned conventional circumstances, and provides an aromatic compound having excellent heat resistance, excellent solubility, excellent electron transport properties, and excellent durability to alcohol solvents in thin films. The challenge is to

The present invention also provides an organic electroluminescent device containing the compound, a display device and a lighting device comprising the organic electroluminescent device, a composition containing the compound and a solvent, a method for forming a thin film, and a method for manufacturing an organic electroluminescent device. The task is to provide

In this specification, "alcohol solvent" may be referred to as "alcohol-based solvent" or "alcohol-based solvent".

As a result of extensive studies, the present inventors have found that the above problems can be solved by using triazine and an aromatic compound having a spirobifluorene structure, and have arrived at the present invention.

That is, the gist of the present invention is as follows <1> to <21>.
<1>
An aromatic compound represented by the following formula (1).

(In formula (1), G ¹ and G ² each independently represent formula (3) below, and G ³ represents formula (4) below.)

(In formula (3), an asterisk (*) represents a bond with formula (1),
L ² is an optionally substituted divalent aromatic hydrocarbon group having 60 or less carbon atoms, an optionally substituted divalent heteroaromatic group having 60 or less carbon atoms, or A plurality of groups selected from optionally substituted divalent C 60 or less aromatic hydrocarbon groups and optionally substituted divalent C 60 or less heteroaromatic groups is a group to which the group is linked,
Ar ² is an optionally substituted monovalent aromatic hydrocarbon group having 60 or less carbon atoms, an optionally substituted monovalent heteroaromatic group having 60 or less carbon atoms, or A plurality of groups selected from optionally substituted monovalent aromatic hydrocarbon groups having 60 or less carbon atoms and optionally substituted monovalent heteroaromatic groups having 60 or less carbon atoms is a group to which the group is linked,
^a2 represents an integer of 1 to 5; )

(In formula (4), an asterisk (*) represents a bond with formula (1),
L ³ is an optionally substituted divalent aromatic hydrocarbon group having 60 or less carbon atoms, an optionally substituted divalent heteroaromatic group having 60 or less carbon atoms, or A plurality of groups selected from optionally substituted divalent C 60 or less aromatic hydrocarbon groups and optionally substituted divalent C 60 or less heteroaromatic groups is a group to which the group is linked,
^a3 represents an integer of 1 to 5; )
<2>
The aromatic compound according to <1>, wherein G ¹ is represented by the following formula (2).

(In formula (2), an asterisk (*) represents a bond with formula (1),
L ¹ is an optionally substituted divalent aromatic hydrocarbon group having 60 or less carbon atoms, an optionally substituted divalent heteroaromatic group having 60 or less carbon atoms, or A plurality of groups selected from optionally substituted divalent C 60 or less aromatic hydrocarbon groups and optionally substituted divalent C 60 or less heteroaromatic groups is a group to which the group is linked,
Ar ¹ is an optionally substituted monovalent aromatic hydrocarbon group having 60 or less carbon atoms, an optionally substituted monovalent heteroaromatic group having 60 or less carbon atoms, or A plurality of groups selected from optionally substituted monovalent aromatic hydrocarbon groups having 60 or less carbon atoms and optionally substituted monovalent heteroaromatic groups having 60 or less carbon atoms is a group to which the group is linked,
a ¹ represents an integer of 0 to 5; )
<3>
The aromatic compound according to <2>, wherein each of L ¹ to L ³ is independently a phenyl group or a group in which a plurality of phenyl groups are linked.
<4>
The aromatic compound according to <2> or <3>, wherein L ¹ to L ³ are each independently a 1,3-phenylene group or a 1,4-phenylene group.
<5>
The aromatic compound according to any one of <1> to <4>, which has a molecular weight of 1200 or more.
<6>
An organic electroluminescence device having an anode and a cathode on a substrate and an organic layer between the anode and the cathode,
The organic layer has a layer containing an organic electroluminescence device material,
An organic electroluminescent device, wherein the organic electroluminescent device material is the aromatic compound according to any one of <1> to <5>.
<7>
The organic electroluminescent device according to <6>, wherein the layer containing the organic electroluminescent device material is a light-emitting layer.
<8>
A display device comprising the organic electroluminescent element according to <6> or <7>.
<9>
A lighting device comprising the organic electroluminescent element according to <6> or <7>.

<10>
A composition for an organic electroluminescence device, comprising the aromatic compound according to any one of <1> to <5> and a solvent.
<11>
The composition for an organic electroluminescence device according to <10>, further comprising a phosphorescent material and a charge transport material.
<12>
The composition for an organic electroluminescent element according to <11>, wherein the charge-transporting material is a compound represented by the following formula (240) or a compound represented by the following formula (260).

(In formula (240),
Ar ⁶¹¹ and Ar ⁶¹² each independently represent an optionally substituted monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms,
R ⁶¹¹ and R ⁶¹² are each independently a deuterium atom, a halogen atom, or an optionally substituted monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms,
G represents a single bond or an optionally substituted divalent aromatic hydrocarbon group having 6 to 50 carbon atoms,
n ⁶¹¹ and n ⁶¹² are each independently an integer of 0-4. )

(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 It represents a branched and linked monovalent group.)
<13>
The organic according to <12>, wherein each of Ar ⁶¹¹ and Ar ⁶¹² in the formula (240) is independently a monovalent group in which a plurality of optionally substituted benzene rings are bonded in a chain or branched manner A composition for an electroluminescence device.
<14>
<12> or <13>, wherein R ⁶¹¹ and R ⁶¹² in formula (240) are each independently an optionally substituted monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms. A composition for an organic electroluminescence device.
<15>
The composition for an organic electroluminescence element according to any one of <12> to <14>, wherein n ⁶¹¹ and n ⁶¹² in formula (240) are each independently 0 or 1.
<16>
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 for an organic electroluminescence element according to <12>, wherein these structures may have the substituents.

<17>
A method for forming a thin film, comprising a step of forming a film from the composition for an organic electroluminescent device according to any one of <10> to <16> by a wet film-forming method.
<18>
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:
A method for producing an organic electroluminescent device, comprising forming the organic layer by a wet film-forming method using the composition for an organic electroluminescent device according to any one of <10> to <16>.
<19>
The method for producing an organic electroluminescence device according to <18>, wherein the organic layer is a light-emitting layer.
<20>
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 includes a light-emitting layer and an electron-transporting layer, and the light-emitting layer is formed by a wet film-forming method using the composition for an organic electroluminescent element according to any one of <10> to <16>. process and
forming the electron transport layer by a wet film-forming method using an electron transport layer composition containing an electron transport material and a solvent, in this order.
<21>
The method for producing an organic electroluminescence device according to <20>, wherein the solvent contained in the electron transport layer composition is an alcohol solvent.

According to the present invention, it is possible to provide an aromatic compound having excellent heat resistance, excellent solubility, excellent electron transport properties, and excellent durability to alcohol solvents in thin films.

In addition, according to the present invention, an organic electroluminescent device having the compound, a display device and a lighting device having the organic electroluminescent device, a composition containing the compound and a solvent, a method for forming a thin film, and a method for manufacturing an organic electroluminescent device are provided. can provide.

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 represented by the following formula (1).

(In formula (4), an asterisk (*) represents a bond with formula (1),
L ³ is an optionally substituted divalent aromatic hydrocarbon group having 60 or less carbon atoms, an optionally substituted divalent heteroaromatic group having 60 or less carbon atoms, or A plurality of groups selected from optionally substituted divalent C 60 or less aromatic hydrocarbon groups and optionally substituted divalent C 60 or less heteroaromatic groups is a group to which the group is linked,
^a3 represents an integer of 1 to 5; )

From the viewpoint of electron transport properties, ^G1 is preferably represented by the following formula (2).

(In formula (2), an asterisk (*) represents a bond with formula (1),
L ¹ is an optionally substituted divalent aromatic hydrocarbon group having 60 or less carbon atoms, an optionally substituted divalent heteroaromatic group having 60 or less carbon atoms, or A plurality of groups selected from optionally substituted divalent C 60 or less aromatic hydrocarbon groups and optionally substituted divalent C 60 or less heteroaromatic groups is a group to which the group is linked,
Ar ¹ is an optionally substituted monovalent aromatic hydrocarbon group having 60 or less carbon atoms, an optionally substituted monovalent heteroaromatic group having 60 or less carbon atoms, or A plurality of groups selected from optionally substituted monovalent aromatic hydrocarbon groups having 60 or less carbon atoms and optionally substituted monovalent heteroaromatic groups having 60 or less carbon atoms is a group to which the group is linked,
a ¹ represents an integer of 0 to 5; )

In the present invention, the action mechanism by which effective effects are obtained is presumed as follows.

The aromatic compound of the present invention has a spirobifluorene structure represented by formula (4), and therefore has a high glass transition temperature. In the aromatic compound of the present invention, since the triazine skeleton and the spirobifluorene structure are bonded via a structure larger than that of biphenyl, steric hindrance due to the spirobifluorene structure can be suppressed and the electron transport property is high. In addition, the aromatic compound of the present invention has a biphenyl group to which the spirobifluorene structure represented by formula (4) is bonded at the meta position, and thus has high solubility. Since the compound of the present invention has a large molecular weight and at least one spirobifluorene structure, it has excellent resistance to alcohol solvents after film formation.

In addition, in the frontier molecular orbital of the aromatic compound of the present invention, the LUMO orbital is easily localized in the triazine structure represented by formula (1), and the HOMO orbital is localized in the spirobifluorene structure represented by formula (3). It is easy to be tarnished and the durability can be improved.

Using the aromatic compound of the present invention, it is possible to easily provide an organic electroluminescence device that has excellent driving stability and can be driven at a low driving voltage and with high efficiency.

The organic electroluminescent device of the present invention containing the aromatic compound of the present invention has excellent electrochemical stability, low driving voltage and high efficiency. Therefore, the organic electroluminescence device of the present invention can be used as a flat panel display (for example, an OA computer display or a wall-mounted TV), an in-vehicle display device, a mobile phone display, or a light source (for example, a copier (light sources for liquid crystal displays and instruments, backlight sources for instruments), display boards, and indicator lamps, and their technical value is great.

<Ar ¹ , Ar ² >
Ar ¹ and Ar ² each independently represent an optionally substituted monovalent aromatic hydrocarbon group having 60 or less carbon atoms and an optionally substituted monovalent carbon number of 60 or less or an optionally substituted monovalent aromatic hydrocarbon group having 60 or less carbon atoms and an optionally substituted monovalent heteroaromatic group having 60 or less carbon atoms represents a group in which a plurality of groups selected from groups are linked;

Examples of monovalent aromatic hydrocarbon groups having 60 or less carbon atoms include benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, tetraphenylene ring, chrysene ring, pyrene ring, benzanthracene ring, perylene ring, biphenyl ring, or a monovalent group of a terphenyl ring.

Examples of monovalent heteroaromatic groups having 60 or less carbon atoms include furan ring, benzofuran ring, dibenzofuran ring, thiophene ring, benzothiophene ring, dibenzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole 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, cinnoline ring, quinoxaline ring, perimidine ring, quinazoline ring, quinazolinone ring, or azulene ring.

From the viewpoint of solubility and durability of the compound, it is preferably a phenyl group, a group in which a plurality of phenyl groups are linked, or a naphthyl group, and more preferably a phenyl group or a group in which a plurality of phenyl groups are linked.

<L ¹ , L ² , L ³ >
L ¹ , L ² and L ³ are each independently an optionally substituted divalent aromatic hydrocarbon group having 60 or less carbon atoms, an optionally substituted divalent carbon A heteroaromatic group having a number of 60 or less, or an optionally substituted divalent aromatic hydrocarbon group having 60 or less carbon atoms and an optionally substituted divalent carbon number of 60 or less represents a group in which a plurality of groups selected from heteroaromatic groups are linked.

Examples of divalent aromatic hydrocarbon groups having 60 or less carbon atoms include divalent benzene ring, naphthalene ring, anthracene ring, tetraphenylene ring, phenanthrene ring, chrysene ring, pyrene ring, benzanthracene ring, or perylene ring. group.

Examples of divalent heteroaromatic groups having 60 or less carbon atoms include furan ring, benzofuran ring, dibenzofuran ring, thiophene ring, benzothiophene ring, dibenzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole 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, cinnoline ring, quinoxaline ring, perimidine ring, quinazoline ring, quinazolinone ring or azulene ring.

From the viewpoint of solubility and durability of the compound, it is preferably a phenyl group, a group in which a plurality of phenyl groups are linked, or a naphthyl group, and more preferably a phenyl group or a group in which a plurality of phenyl groups are linked. Among these, a 1,3-phenylene group or a 1,4-phenylene group is more preferable.

^{^{<a1 to a3>}}
a ¹ represents an integer of 0 to 5, and a ² and a ³ each independently represent an integer of 1 to 5; From the viewpoint of solubility and durability of the compound, ^a1 and ^a3 are preferably 3 or less, more preferably 2 or less, particularly preferably 1, and ^a2 is preferably 4 or less, further preferably 3 or less.

When a ¹ to a ³ are 2 or more, a plurality of L ¹ to L ³ may be the same or different.

<(L ¹ ) _a1 , (L ² ) _a2 , (L ³ ) _a3 >
At least one of (L ¹ ) _a1 , (L ² ) _a2 and (L ³ ) _a3 is a partial structure represented by the following formula (11), a partial structure represented by the following formula (12), from the viewpoint of compound solubility and durability. ) and at least one partial structure selected from the partial structure represented by the following formula (13).

In each of the above formulas (11) to (13), * 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 (L ¹ ) _a1 , (L ² ) _a2 and (L ³ ) _a3 has at least the partial structure represented by formula (11) or the partial structure represented by formula (12). have.
More preferably, each of (L ¹ ) _a1 , (L ² ) _a2 and (L ³ ) _a3 has at least the partial structure represented by formula (11) or the partial structure represented by formula (12).
Particularly preferably, (L ² ) _a2 has a partial structure represented by formula (11) and a partial structure represented by formula (12).

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

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

Further, in the case of 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) It is more preferable to have at least one partial structure selected from the following formulas (14) to (18), which is a structure containing a plurality of structures selected from:

The structure containing a plurality of structures selected from the partial structure represented by the formula (11) and the partial structure represented by the formula (12) is, for example, the formula (14), such as the following formula (14a), the formula It is a partial structure having one partial structure represented by (11) and two partial structures represented by formula (12).

Still more preferably, at least one of (L ¹ ) _a1 , (L ² ) _a2 and (L ³ ) _a3 is at least the partial structure represented by formula (14) or the moiety represented by formula (15) have a structure.

Formula (14) is preferably the following formula (14-2).

Formula (14) is more preferably formula (14-3) below.

Formula (15) is preferably the following formula (15-2).

Formula (15) is more preferably formula (15-3) below.

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

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

Further, it is more preferable to have a partial structure represented by the following formula (19) or a partial structure represented by the following formula (20) as the structure containing the partial structure represented by the formula (13).

In each of the above formulas (14) to (20), * 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 (14) to (20), formulas (14-3) and (15-3) are preferred, and formula (14-3) is more preferred.

<Substituent>
The substituents that Ar ¹ to Ar ² and L ¹ to L ³ may have may be selected from the substituent group Z.

[Substituent group Z]
Substituent group Z includes an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyl group, a halogen atom, a haloalkyl group, an alkylthio group, an arylthio group, a silyl group, a siloxy group, and a cyano group. , an aralkyl group, an aromatic hydrocarbon group, or a heteroaromatic group.

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.

Examples of heteroaromatic groups include furan ring, benzofuran ring, dibenzofuran ring, thiophene ring, benzothiophene ring, dibenzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, pyrrolo imidazole 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, A pyrimidine ring, a triazine ring, a quinoline ring, an isoquinoline ring, a cinnoline ring, a quinoxaline ring, a perimidine ring, a quinazoline ring, a quinazolinone ring, or an azulene ring having usually 4 or more carbon atoms, usually 30 or less, preferably 18 or less, and further Heteroaromatic groups, preferably 12 or less, are mentioned.

Among the substituent group Z, an alkyl group, an alkoxy group, an aralkyl group and an aromatic hydrocarbon group are preferable, and an alkyl group having 10 or less carbon atoms, an aralkyl group having 30 or less carbon atoms, and an aralkyl group having 30 or less carbon atoms are more preferable. It is an aromatic hydrocarbon group of 30 or less, more preferably an aromatic hydrocarbon group of 30 or less carbon atoms, and particularly preferably having no substituent.

Further, each substituent in the substituent group Z may further have a substituent. As such additional substituents, the same substituents as those described above (substituent group Z) can be used. From the viewpoint of charge transport properties, the substituents in the substituent group Z preferably have no further substituents.

<Molecular weight>
The molecular weight of the aromatic compound of the present invention is preferably 1,000 or more, more preferably 1,100 or more, most preferably 1,200 or more, and preferably 5,000 or less, more preferably 4,000 or less, and particularly preferably 3,000 or less. Yes, and most preferably 2000 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>
The aromatic compound of the present invention can be produced, for example, according to the method described in Examples.

[Uses of aromatic compounds]
The aromatic compound of the present invention is preferably used as an organic electroluminescent element material for an organic layer of an organic electroluminescent element, and the organic layer is preferably a light-emitting layer. An organic electroluminescent device can have, for example, an anode and a cathode on a substrate, and an organic layer between the anode and the cathode. 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.

The organic layer containing the aromatic compound of the present invention may be formed by a vapor deposition method or by a wet film formation method.

In this specification, when the aromatic compound of the present invention is used in the organic layer of an organic electroluminescent device, the aromatic compound of the present invention is also referred to as a material for organic electroluminescent devices.

[Composition]
When the organic layer containing the aromatic compound of the present invention is formed by a wet film formation method, at least the aromatic compound represented by the formula (1) and a solvent (hereinafter sometimes referred to as "organic solvent" ) is wet film-formed. That is, the composition of the present invention contains at least the aromatic compound represented by formula (1) and an organic solvent.

The composition of the present invention is suitably used as a composition for organic electroluminescent elements for forming organic electroluminescent elements.

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. As the luminescent material, a phosphorescent luminescent material is preferable.

The composition of the present invention preferably further contains a light-emitting material and a charge-transporting material, and is suitably used as a composition for forming a light-emitting layer of an organic electroluminescence device. As the luminescent material, a phosphorescent luminescent material is preferable.

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

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 in 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, 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 preferred are pyridine ring, pyrazine ring, pyrimidine ring, imidazole ring, benzothiazole ring, benzoxazole ring, quinoline ring, isoquinoline ring, quinoxaline ring and quinazoline ring,
More preferred are pyridine ring, imidazole ring, benzothiazole ring, quinoline ring, isoquinoline ring, quinoxaline ring and quinazoline ring,
Most preferred are pyridine ring, imidazole ring, benzothiazole ring, quinoline ring, quinoxaline ring and quinazoline ring.

A preferred combination of ring A1 and ring A2 is 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), (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 of Ar ²⁰¹ , Ar ²⁰² and Ar ²⁰³ is an optionally substituted aromatic hydrocarbon ring structure,
The aromatic hydrocarbon ring structure is preferably an aromatic hydrocarbon ring having 6 to 30 carbon atoms,
Specifically, benzene ring, naphthalene ring, anthracene ring, triphenylyl ring, acenaphthene ring, fluoranthene ring, and fluorene ring are preferred.
More preferably, a benzene ring, a naphthalene ring, or a fluorene ring,
A benzene ring is most 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 one 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 ortho- or meta-position. , more preferably, at least one benzene ring is attached to the adjacent structure at the meta position.

When any of Ar ²⁰¹ , Ar ²⁰² and Ar ²⁰³ is an aromatic heterocyclic structure optionally having a substituent,
The aromatic heterocyclic ring structure 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, 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, carbazole ring, dibenzofuran ring, dibenzothiophene ring,
More preferred are pyridine ring, pyrimidine 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 an aliphatic hydrocarbon having 1 to 24 carbon atoms,
more preferably aliphatic hydrocarbons having 1 to 12 carbon atoms,
More preferred are aliphatic hydrocarbons having 1 to 8 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, 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)
Among these substituent group 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, and at least one hydrogen atom of these groups is fluorine. a group substituted with an 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 heteroaryl 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 , −SF ₅ , and
more 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,
Particularly preferred are alkyl groups, arylamino groups, aralkyl groups, alkenyl groups, aryl groups and heteroaryl groups,
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 preferable.

In a structure having a group to which a benzene ring is 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 1-12, preferably 3-8,
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 a 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, 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 compound of the present invention and/or other charge-transporting materials, so that a light-emitting layer with high light-emitting efficiency can be obtained.

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-transporting material other than the aromatic compound of the present invention 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. preferably Furthermore, in the present invention, the charge transport material also includes a material that adjusts the charge transport 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.

In the composition of the present invention, since the compound represented by the formula (1) functions as an electron-transporting material, it is preferable to further include a hole-transporting material as a charge-transporting material. A 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. is preferable as a structure having excellent hole-transporting properties, and a carbazole structure, a dibenzofuran structure, or a triarylamine structure is more preferable. Particularly preferred is a compound represented by formula (240) described later.

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.

Among the charge-transporting materials used as the host material of the light-emitting layer, the material for adjusting the charge-transporting property is preferably a compound represented by the formula (260) described later, which is a compound having a structure in which a large number of benzene rings are linked. 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 compound of the present invention having excellent electron transport properties, a compound represented by the formula (240) described later and/or the formula (260) described later It is preferable to contain a compound represented by as a charge transport material. Inclusion of such a compound 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 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 2,000 or less, usually 600 or more, preferably 800 or more, more preferably 1,100 or more, when the layer formed in contact with the light emitting layer is formed by a wet film formation method is preferably 1,000 or more, more preferably 1,100 or more, and particularly preferably 1,200 or more.

<Ar ⁶¹¹ , Ar ⁶¹² >
Ar ⁶¹¹ and Ar ⁶¹² each independently represent an optionally substituted monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms.
The number of carbon atoms in the aromatic hydrocarbon group is preferably 6-50, more preferably 6-30, still more preferably 6-18. Specific examples of the aromatic hydrocarbon group include a benzene ring, naphthalene ring, anthracene ring, tetraphenylene ring, phenanthrene ring, chrysene ring, pyrene ring, benzanthracene ring, perylene ring, and the like, which usually have 6 carbon atoms. Above, usually 30 or less, preferably 18 or less, more preferably 14 or less monovalent group of aromatic hydrocarbon structure, or a plurality of structures selected from these structures are bonded in a chain or branched and a monovalent group having a structure such as When a plurality of aromatic hydrocarbon rings are linked, a structure in which 2 to 8 rings are linked is usually mentioned, and a structure in which 2 to 5 rings are linked is preferable. When a plurality of aromatic hydrocarbon rings are linked, the same structure may be linked, or different structures may be linked.

Ar ⁶¹¹ and Ar ⁶¹² are preferably each independently a phenyl group,
a monovalent group in which a plurality of benzene rings are bonded in a chain or branched manner;
a monovalent group in which one or more benzene rings and at least one naphthalene ring are linked in a chain or branched manner;
a monovalent group in which one or more benzene rings and at least one phenanthrene ring are linked in a chain or branch, or
a monovalent group in which one or more benzene rings and at least one tetraphenylene ring are linked in a chain or branched manner;
and more preferably a monovalent group in which a plurality of benzene rings are bonded in a chain or branched manner, and in any case, the order of bonding is not critical.
Ar ⁶¹¹ and Ar ⁶¹² are each independently particularly preferably a monovalent group in which a plurality of optionally substituted benzene rings are bonded in a chain or branched manner, and each independently represents a plurality of benzene Most preferably, the ring is a multi-chain or branched monovalent group.

The number of bonded benzene rings, naphthalene rings, phenanthrene rings and tetraphenylene rings is usually 2-8, preferably 2-5, as described above. Among them, preferably, a monovalent structure in which 1 to 4 benzene rings are connected, a monovalent structure in which 1 to 4 benzene rings and a naphthalene ring are connected, 1 in which 1 to 4 benzene rings and a phenanthrene ring are connected It is a valent structure or a monovalent structure in which 1 to 4 benzene rings and a tetraphenylene ring are linked.

These aromatic hydrocarbon groups may have substituents. The substituents that the aromatic hydrocarbon group may have are as described above, and specifically can be selected from the substituent group Z2. Preferred substituents are the preferred substituents of the substituent group Z2.

At least one of Ar ⁶¹¹ and Ar ⁶¹² preferably has at least one partial structure selected from the following formulas (72-1) to (72-7) from the viewpoint of compound solubility and durability.

In each of the above formulas (72-1) to (72-7), * 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 Ar ⁶¹¹ and Ar ⁶¹² has at least one partial structure selected from formulas (72-1) to (72-4) and formula (72-7).
More preferably, each of Ar ⁶¹¹ and Ar ⁶¹² has at least one partial structure selected from formulas (72-1) to (72-3) and formula (72-7).
Particularly preferably, each of Ar ⁶¹¹ and Ar ⁶¹² has at least one partial structure selected from formula (72-1), formula (72-2) and formula (72-7).

Formula (72-2) is preferably the following formula (72-2-2).

The formula (72-2) is more preferably the following formula (72-2-3).

Further, from the viewpoint of the solubility and durability of the compound, the partial structure that at least one of Ar ⁶¹¹ and Ar ⁶¹² preferably has is the partial structure represented by formula (72-1) and the partial structure represented by formula (72-2). A partial structure having a partial structure that is

< ^R611 , ^R612 >
Each of R ⁶¹¹ and R ⁶¹² is independently a deuterium atom, a halogen atom such as a fluorine atom, or an optionally substituted monovalent aromatic hydrocarbon having 6 to 50 carbon atoms.
A monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent is preferred.
The aromatic hydrocarbon group is preferably a monovalent group having an aromatic hydrocarbon structure having 6 to 30 carbon atoms, more preferably 6 to 18 carbon atoms, and particularly preferably 6 to 10 carbon atoms.
Specific examples of the monovalent aromatic hydrocarbon group are the same as those of Ar ⁶¹¹ , and the same is true of the preferred aromatic hydrocarbon group, and the phenyl group is particularly preferred.
These aromatic hydrocarbon groups may have a substituent. The substituents that the aromatic hydrocarbon group may have are as described above, and specifically can be selected from the group of substituents Z2 described later. Preferred substituents are the preferred substituents of the substituent group Z2 described later.

< ⁿ⁶¹¹ , ⁿ⁶¹² >
n ⁶¹¹ and n ⁶¹² are each independently an integer of 0-4. It is preferably 0 to 2, more preferably 0 or 1.

<Substituent>
When Ar ⁶¹¹ , Ar ⁶¹² , R ⁶¹¹ and R ⁶¹² are monovalent aromatic hydrocarbon groups, the substituents they may have are preferably substituents 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.

<G>
G represents a single bond or an optionally substituted divalent aromatic hydrocarbon group having 6 to 50 carbon atoms.

The number of carbon atoms in the aromatic hydrocarbon group of G is preferably 6-50, more preferably 6-30, more preferably 6-18. Specific examples of the aromatic hydrocarbon group include a benzene ring, naphthalene ring, anthracene ring, tetraphenylene ring, phenanthrene ring, chrysene ring, pyrene ring, benzanthracene ring, perylene ring, and the like, which usually have 6 carbon atoms. Above, usually 30 or less, preferably 18 or less, more preferably 14 or less divalent groups of aromatic hydrocarbon structures, or a plurality of structures selected from these structures are linked in a chain or branched manner and a divalent group having a structure such as When a plurality of aromatic hydrocarbon rings are linked, a structure in which 2 to 8 rings are linked is usually mentioned, and a structure in which 2 to 5 rings are linked is preferable. When a plurality of aromatic hydrocarbon rings are linked, the same structure may be linked, or different structures may be linked.

G is preferably
single bond,
a phenylene group,
a divalent group in which a plurality of benzene rings are bonded in a chain or branched manner;
a divalent group in which one or more benzene rings and at least one naphthalene ring are linked in a chain or branched manner;
a divalent group in which one or more benzene rings and at least one phenanthrene ring are linked in a chain or branched manner, or
a divalent group in which one or more benzene rings and at least one tetraphenylene ring are linked in a chain or branched manner;
and more preferably a divalent group in which a plurality of benzene rings are bonded in a chain or branched manner, and in any case, the order of bonding does not matter.

The number of bonded benzene rings, naphthalene rings, phenanthrene rings and tetraphenylene rings is usually 2-8, preferably 2-5, as described above. Among them, more preferably, a bivalent structure in which 1 to 4 benzene rings are linked, a bivalent structure in which 1 to 4 benzene rings and a naphthalene ring are linked, 1 to 4 benzene rings and a phenanthrene ring are linked It is a bivalent structure, or a bivalent structure in which 1 to 4 benzene rings and a tetraphenylene ring are linked.

<Molecular weight>
The compound represented by the formula (240) is a low-molecular-weight material, and has a molecular weight of preferably 3,000 or less, more preferably 2,500 or less, still more preferably 2,000 or less, and particularly preferably 1 , 500 or less, usually 300 or more, preferably 350 or more, more preferably 400 or more.

<Specific examples of compound IV represented by the above formula (240)>
Preferable specific examples of compound IV represented by formula (240) are shown below, but the present invention is not limited thereto.

The composition for forming a light-emitting layer of the present invention may contain only one compound represented by the formula (240), or may contain two or more compounds.

[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 It 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 2 to 10 phenyl groups which may have a substituent, which are unbranched or branched and linked 1 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 having 2 to 10 phenyl groups which may be substituted.
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
These structures may have the substituents described above, and may be substituted with alkyl groups as the substituents, for example. 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. Examples of such other solvents include amides such as N,N-dimethylformamide and N,N-dimethylacetamide, and dimethylsulfoxide.

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]
The solid content concentration in the composition for organic electroluminescent elements [the aromatic hydrocarbon compound of the present invention, the light-emitting material, the host material other than the aromatic hydrocarbon compound of the present invention, and the components that can be added as necessary (leveling agents, etc. ) is usually 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and still more preferably 0.5% by mass or more, The content is 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 hydrocarbon 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 hydrocarbon compound of the present invention and the aromatic hydrocarbon compound of the present invention.

In the composition for an organic electroluminescent element of the present invention, the mass ratio of the compound of the present invention to the mass of all host materials of 100, that is, the mass ratio of the compound of the present invention to the mass of all host materials in the light-emitting layer of 100 is 5 or more. , preferably 10 or more, more preferably 15 or more, more preferably 20 or more, particularly preferably 30 or more, 99 or less, preferably 95 or less, further preferably 90 or less, more preferably 80 or less, particularly preferably is 70 or less.

Further, in the composition for an organic electroluminescence device of the present invention, the molar ratio of the compound of the present invention to the total host material, that is, the molar ratio of the compound of the present invention to the total host material in the light-emitting layer is preferably 5 mol% or more. is 10 mol% or more, more preferably 20 mol% or more, more preferably 25 mol% or more, particularly preferably 30 mol% or more, 90 mol% or less, preferably 80 mol% or less, more preferably is 70 mol % or less, particularly preferably 60 mol % or less.

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 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. . Moreover, when the composition of the present invention contains a light-emitting material, a light-emitting layer can be formed by this method. Examples of coating 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. It refers to a method of forming a film by employing a wet film-forming method such as a printing method or 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 150° 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-based solvent is preferable. As the electron transport layer material of the electron transport layer-forming composition, an electron transport material soluble in the alcohol solvent is preferable.

As the alcohol-based solvent, aliphatic alcohols with 3 or more carbon atoms are preferred. 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, 1,2-hexanediol, 1-hexanol, 1-heptanol, 3,5,5-trimethyl-1-hexanol, 2-methyl-2- Pentanol, 4-methyl-3-heptanol, 3-methyl-2-pentanol, 4-methyl-1-pentanol, 1-nonen-3-ol, 4-heptanol, 1-methoxy-2-propanol, 3-methyl-1-pentane tanol, 4-octanol, 3,3-diethoxy-1-propanol, 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]
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. is preferably a polymer having repeating units linked directly or via a linking group.

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 in the present invention preferably contains the aromatic compound and the luminescent material of the present 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.

There are no restrictions on the method of forming the hole blocking layer. Therefore, it can be formed by a wet film forming method, a vapor deposition method, or other methods.

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, for example, a metal complex such as an aluminum complex of 8-hydroxyquinoline (Japanese Patent Laid-Open No. 59-194393), 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 Patent No. 5645948), 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'-dicyano Anthraquinonediimine, 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 transport layer 6 is formed on the hole blocking layer by a wet film forming method or a vacuum vapor 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.

[Method for producing organic electroluminescent device]
The method for producing an organic electroluminescent device of the present invention uses the composition for an organic electroluminescent device described above. An organic electroluminescent device can have, for example, an anode and a cathode on a substrate, and an organic layer between the anode and the cathode.

One aspect of the method for producing an organic electroluminescent device of the present invention can include a step of forming an organic layer by a wet film-forming method using the composition for an organic electroluminescent device described above. The organic layer can be, for example, an emissive layer.

As another aspect of the method for producing an organic electroluminescent device of the present invention, the organic layer includes a light-emitting layer and an electron-transporting layer, and the light-emitting layer is formed by a wet film-forming method using the composition for an organic electroluminescent device described above. and a step of forming the electron transport layer by a wet film-forming method using an electron transport layer composition containing an electron transport material and a solvent, in this order. The solvent contained in the electron transport layer composition can be an alcohol solvent. Also, the electron transport layer formed by the wet film formation method can be formed so as to be directly laminated on the light emitting layer formed by the wet film formation method.

<Organic EL display device>
The organic EL display device (organic electroluminescence element display device or display device) of the present invention comprises the organic electroluminescence 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.

<Organic EL lighting>
The organic EL lighting (organic electroluminescence device lighting or lighting device) of the present invention comprises the organic electroluminescence device 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.

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. Various conditions and values of evaluation results in the following examples have the meaning of preferable upper or lower limit values in the embodiments of the present invention. It may be a range defined by a value in an example or a combination of values between examples.

In this specification, Ac means an acetyl group, Ph means a phenyl group, dppf means 1,1'-bis(diphenylphosphino)ferrocene, and DMSO means dimethylsulfoxide. Compound 1-g and comparative compound (C-1) were synthesized according to the method described in Patent Document 1 (International Publication No. 2012/137958).

<Synthesis Example 1: Synthesis Example of Compound (H-1)>
(Synthesis of compound 1-c)

Compound 1-a (15.0 g, 41.6 mmol) and compound 1-b (14.9 g, 41.6 mmol) were subjected to nitrogen bubbling toluene (100 mL), ethanol (50 mL), tripotassium phosphate aqueous solution (2 .0 mol/L, 50 mL) was sequentially added and heated to 50°C. PdCl ₂ (PPh ₃ ) ₂ (0.29 g, 0.41 mmol) was then added and stirred at 65° C. for 2 hours. After cooling to room temperature, a saturated sodium chloride aqueous solution was added, and extraction was performed using toluene. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain compound 1-c (21.6 g, 95% yield).

(Synthesis of compound 1-d)

Dehydrated DMSO (200 mL) was added to compound 1-c (21.6 g, 39.5 mmol), bis(pinacolatodiboron) (15.0 g, 59.2 mmol) and potassium acetate (11.6 g, 118.5 mmol). , and heated to 50°C. PdCl ₂ (dppf)CH ₂ Cl ₂ (1.61 g, 1.98 mmol) was added and stirred at 90° C. for 3 hours. After cooling to room temperature, distilled water was added and suction filtration was performed. The filtrate was dissolved in toluene, washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain compound 1-d (20.5 g, 87% yield).

(Synthesis of compound 1-e)

Compound 1-d (20.5 g, 34.4 mmol), 1-bromo-4-iodobenzene (9.75 g, 34.4 mmol) were subjected to nitrogen bubbling toluene (100 mL), ethanol (50 mL), triphosphate A potassium aqueous solution (2.0 mol/L, 50 mL) was sequentially added and heated to 50°C. PdCl ₂ (PPh ₃ ) ₂ (0.24 g, 0.34 mmol) was then added and stirred at 65° C. for 2 hours. After cooling to room temperature, a saturated sodium chloride aqueous solution was added, and extraction was performed using toluene. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain compound 1-e (17.8 g, 83% yield).

(Synthesis of compound 1-f)

Dehydrated DMSO (200 mL) was added to compound 1-e (16.8 g, 26.9 mmol), bis(pinacolatodiboron) (10.3 g, 40.4 mmol) and potassium acetate (7.92 g, 80.7 mmol). , and heated to 50°C. PdCl ₂ (dppf)CH ₂ Cl ₂ (1.10 g, 1.35 mmol) was added and stirred at 90° C. for 2 hours. After cooling to room temperature, distilled water was added and suction filtration was performed. The filtrate was dissolved in toluene, washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain compound 1-f (16.2 g, 90% yield).

(Synthesis of compound (H-1))

Under a nitrogen atmosphere, compound 1-f (7.8 g, 11.7 mmol) and compound 1-g (7.7 g, 10.6 mmol) were subjected to nitrogen bubbling in THF (50 mL), tripotassium phosphate aqueous solution (2. 0 mol/L, 15 mL) were sequentially added. After that, Pd(PPh ₃ ) ₄ (0.12 g, 0.11 mmol) was added, and the mixture was heated and stirred at 75° C. for 4 hours. After cooling to room temperature, a saturated aqueous sodium chloride solution and 1N dilute hydrochloric acid were added, and extraction was performed using dichloromethane. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain compound (H-1) (10.7 g, 81% yield).

<Synthesis Example 2: Synthesis Example of Compound (H-2)>
(Synthesis of compound 2-b)

In a nitrogen atmosphere, dehydrated THF (100 mL) was added to compound 2-a (19.6 g, 50.9 mmol) and cooled to -75°C. After that, n-BuLi (1.58 mol/L, 32.2 mL) was added dropwise and stirred at -75°C for 3 hours. The prepared solution was added dropwise to a solution of cyanuric chloride (18.8 g, 101.8 mmol) in dry THF (100 mL) cooled to -100°C. After raising the temperature to room temperature, a saturated aqueous sodium chloride solution and 1N dilute hydrochloric acid were added, and extraction was performed using ethyl acetate. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain compound 2-b (6.5 g, 28% yield).

(Synthesis of compound 2-d)

Under a nitrogen atmosphere, compound 2-b (4.7 g, 10.3 mmol) and compound 2-c (4.5 g, 10.3 mmol) were subjected to nitrogen bubbling in THF (100 mL), tripotassium phosphate aqueous solution (2. 0 mol/L, 13 mL) were sequentially added. After that, Pd(PPh ₃ ) ₄ (0.12 g, 0.10 mmol) was added and heated with stirring at 55° C. for 8 hours. After cooling to room temperature, a saturated aqueous sodium chloride solution and 1N dilute hydrochloric acid were added, and extraction was performed using dichloromethane. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain compound 2-d (4.9 g, 66% yield).

(Synthesis of compound 2-g)

Under a nitrogen atmosphere, compound 2-e (3.3 g, 9.28 mmol) and compound 2-f (3.6 g, 9.28 mmol) were subjected to nitrogen bubbling toluene (40 mL), ethanol (20 mL), triphosphate A potassium aqueous solution (2.0 mol/L, 20 mL) was added in order. After that, Pd(PPh ₃ ) ₄ (0.11 g, 0.093 mmol) was added and heated with stirring at 90° C. for 4 hours. After cooling to room temperature, a saturated sodium chloride aqueous solution was added, and extraction was performed using toluene. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain compound 2-g (2.6 g, 45% yield).

(Synthesis of compound 2-h)

Dehydrated DMSO (50 mL) was added to compound 2-g (2.6 g, 4.17 mmol), bis(pinacolatodiboron) (1.6 g, 6.25 mmol) and potassium acetate (1.2 g, 12.5 mmol). , and heated to 50°C. PdCl ₂ (dppf)CH ₂ Cl ₂ (0.17 g, 0.21 mmol) was added and stirred at 90° C. for 7 hours. After cooling to room temperature, distilled water was added and suction filtration was performed. The filtrate was dissolved in dichloromethane, washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain compound 2-h (0.89 g, 32% yield).

(Synthesis of compound (H-2))

Under a nitrogen atmosphere, compound 2-d (0.64 g, 0.88 mmol) and compound 2-h (0.59 g, 0.88 mmol) were subjected to nitrogen bubbling in THF (30 mL), tripotassium phosphate aqueous solution (2. 0 mol/L, 3 mL) were sequentially added. After that, Pd(PPh ₃ ) ₄ (10 mg, 0.0088 mmol) was added and heated with stirring at 70° C. for 5 hours. After cooling to room temperature, a saturated aqueous sodium chloride solution and 1N dilute hydrochloric acid were added, and extraction was performed using dichloromethane. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain compound (H-2) (0.69 g, 64% yield).

<Synthesis example of compound (H-3)>
(Synthesis of compound 3-b)

In a nitrogen atmosphere, dehydrated THF (100 mL) was added to compound 3-a (22.1 g, 57.3 mmol) and cooled to -75°C. After that, n-BuLi (1.58 mol/L, 36.3 mL) was added dropwise and stirred at -75°C for 3 hours. The prepared solution was added dropwise to a solution of cyanuric chloride (4.75 g, 25.8 mmol) in dry THF (100 mL) cooled to -100°C. After raising the temperature to room temperature, a saturated aqueous sodium chloride solution and 1N dilute hydrochloric acid were added, and extraction was performed using ethyl acetate. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain compound 3-b (5.5 g, 29% yield).

(Synthesis of compound (H-3))

Under a nitrogen atmosphere, compound 3-b (0.85 g, 1.18 mmol) and compound 2-h (0.79 g, 1.18 mmol) were subjected to nitrogen bubbling in THF (30 mL), tripotassium phosphate aqueous solution (2. 0 mol/L, 10 mL) were sequentially added. After that, Pd(PPh ₃ ) ₄ (60 mg, 0.012 mmol) was added, and the mixture was heated and stirred at 70° C. for 3 hours. After cooling to room temperature, a saturated aqueous sodium chloride solution and 1N dilute hydrochloric acid were added, and extraction was performed using dichloromethane. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain compound (H-3) (0.72 g, 50% yield).

(Synthesis of comparative compound (C-2))

Under a nitrogen atmosphere, compound C2-a (1.16 g, 2.49 mmol) and compound C2-b (0.89 g, 2.49 mmol) were subjected to nitrogen bubbling in THF (15 mL), tripotassium phosphate aqueous solution (2. 0 mol/L, 5 mL) were sequentially added. After that, Pd(PPh ₃ ) ₄ (29 mg, 0.025 mmol) was added, and the mixture was heated and stirred at 70° C. for 5 hours. After cooling to room temperature, a saturated aqueous sodium chloride solution and 1N dilute hydrochloric acid were added, and extraction was performed using dichloromethane. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain Comparative Compound (C-2) (1.0 g, 60% yield).

(Synthesis of comparative compound (C-3))

Under a nitrogen atmosphere, compound C3-a (1.15 g, 2.74 mmol) and compound C3-b (1.18 g, 3.29 mmol) were subjected to nitrogen bubbling in THF (20 mL), tripotassium phosphate aqueous solution (2. 0 mol/L, 6 mL) were sequentially added. After that, Pd(PPh ₃ ) ₄ (32 mg, 0.027 mmol) was added, and the mixture was heated and stirred at 70° C. for 5 hours. After cooling to room temperature, the solid was filtered. The filtered product was washed with methanol, acetone and dichloromethane and dried under reduced pressure to obtain Comparative Compound (C-3) (1.3 g, 68% yield).

<Evaluation of compounds (H-1) to (H-3) and comparative compound (C-1)>
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 following comparative compounds (C-1) to (C-3) were used.

<Solubility evaluation of compounds (H-1) to (H-3) and comparative compounds (C-1) to (C-3)>
In addition, to evaluate the solubility of each compound in cyclohexylbenzene (CHB), a cyclohexylbenzene solution of about 1 to 2 mL (concentration of each compound: 12.0% by mass) was prepared, and each compound was added to the solution. It was evaluated whether it was dissolved or not. Table 2 shows the results. "O" in the column "12.0 mass% CHB solution" in Table 2 means that the compound was dissolved in the solution, and "X" means that the compound was not dissolved in the solution.

The compounds (H-1) to (H-3) of the present invention and the comparative compound (C-2) had a solubility in CHB of 12.0% by mass or more.

<Solvent resistance evaluation of compounds (H-1) to (H-2) and comparative compound (C-1) after film formation>
The solvent resistance of each 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 spun 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 100° C. for 10 minutes. The film thickness change before and after the solvent resistance test was estimated from each film thickness difference.
The film thickness after film formation of each compound and the test solvent used are as follows.

(Compound (H-1))
A film of 54 nm was formed using the compound (H-1) of the present invention, and a solvent resistance test was conducted using 1-butanol as the test solvent.

(Compound (H-2))
A film of 54 nm was formed using the compound (H-2) of the present invention, and a solvent resistance test was conducted using 1-butanol as the test solvent.

(Comparative compound (C-1))
A film of 54 nm was formed using the comparative compound (C-1), and a solvent resistance test was conducted using 1-butanol as the test solvent.

The solvent resistance of the compound after film formation was evaluated based on the following criteria.
◯: No decrease in film thickness was observed.
x: A film thickness reduction of 5 nm or more was observed.
Table 3 shows the results of the solvent resistance test.

[Example 1]
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 weight of a hole-transporting polymer compound having a repeating structure of the following formula (P-1) and 0.6% by weight 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 weight 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, 2.3% by weight of the compound (H-1) of the present invention, 2.3% by weight of the compound (HH-1) having the following structure, and 1.3% by weight of (D-1) were used as materials for the light-emitting layer. It was dissolved in cyclohexylbenzene at a concentration of 4% by weight to prepare a composition for forming a light-emitting layer.

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.

[Example 2]
An organic electroluminescence device was produced in the same manner as in Example 1, except that the compound (H-2) of the present invention was used instead of the compound (H-1) as the material for the light-emitting layer.

[Example 3]
An organic electroluminescence device was produced in the same manner as in Example 1, except that the compound (H-3) of the present invention was used instead of the compound (H-1) as the material for the light-emitting layer.

[Comparative Example 1]
An organic electroluminescence device was produced in the same manner as in Example 1, except that the comparative compound (C-2) was used instead of the compound (H-1) as the material of the light-emitting layer.

[Evaluation of element]
Current efficiency (cd/A) and external quantum efficiency (%) were measured when the organic electroluminescence devices obtained in Examples 1 to 3 and Comparative Example 1 were caused to emit light at 1,000 cd/m ² . Also, the time (LT95) for the luminance to decrease to 95% of the initial luminance was measured when the device was continuously energized at a current density of 15 mA/cm ² . These measurement results are shown in Table 4. In Table 4, the values of Examples 1 to 3 are relative values with the value of Comparative Example 1 set to 1. From the results in Table 4, it was found that the performance of the organic electroluminescence device using the compound of the present invention was improved.

[Example 4]
An organic electroluminescence device was produced in the same manner as in Example 1, except that the light-emitting layer was formed as follows.
As materials for the light-emitting layer, the compound (H-1) was 2.7% by weight, the following compound (HH-2) was 2.7% by weight, and the compound (D-1) was cyclohexyl at a concentration of 1.6% by weight. It was made to melt|dissolve in benzene and the composition for light emitting layer formation was prepared.

The composition for forming a light emitting layer was spin-coated on the substrate on which the hole transport layer was formed in a nitrogen glove box, dried on a hot plate in the nitrogen glove box at 120 ° C. for 20 minutes, and a uniform film thickness of 70 nm. A thin film was formed to form a light-emitting layer.

[Example 5]
An organic electroluminescence device was produced in the same manner as in Example 4, except that the compound (H-2) of the present invention was used instead of the compound (H-1) as the material for the light-emitting layer.

[Example 6]
An organic electroluminescence device was produced in the same manner as in Example 4, except that the compound (H-3) of the present invention was used instead of the compound (H-1) as the material for the light-emitting layer.

[Comparative Example 2]
An organic electroluminescence device was produced in the same manner as in Example 4, except that the comparative compound (C-2) was used instead of the compound (H-1) as the material of the light-emitting layer.

[Evaluation of element]
Current efficiency (cd/A) and external quantum efficiency (%) were measured when the organic electroluminescence devices obtained in Examples 4 to 6 and Comparative Example 2 were caused to emit light at 1,000 cd/m ² . Also, the time (LT97) for the luminance to decrease to 97% of the initial luminance was measured when the device was continuously energized at a current density of 15 mA/cm ² . Table 5 shows these measurement results. In Table 5, the values of Examples 4 to 6 are relative values with the value of Comparative Example 2 set to 1. From the results in Table 5, it was found that the performance of the organic electroluminescence device using the compound of the present invention was improved.

Various embodiments have been described above with reference to the drawings, but it goes without saying that the present invention is not limited to such examples. It is obvious that a person skilled in the art can conceive of various modifications or modifications within the scope described in the claims, and these also belong to the technical scope of the present invention. Understood. Moreover, each component in the above embodiments may be combined arbitrarily without departing from the gist of the invention.

This application is based on a Japanese patent application (Japanese Patent Application No. 2021-094594) filed on June 4, 2021, the contents of which are incorporated herein by reference.

The present invention can provide an aromatic compound having excellent heat resistance, excellent solubility, excellent electron transport properties, and excellent resistance to alcohol solvents in thin films. The present invention also provides an organic electroluminescent device containing the compound, a display device and a lighting device comprising the organic electroluminescent device, a composition containing the compound and a solvent, a method for forming a thin film, and a method for manufacturing an organic electroluminescent device. can provide.

REFERENCE SIGNS LIST 1 substrate 2 anode 3 hole injection layer 4 hole transport layer
5 Emissive Layer 6 Electron Transport Layer 7 Cathode 8 Organic Electroluminescent Device

Claims

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

(In formula (1), G 1 and G 2 each independently represent formula (3) below, and G 3 represents formula (4) below.)

(In formula (3), an asterisk (*) represents a bond with formula (1),
L 2 is an optionally substituted divalent aromatic hydrocarbon group having 60 or less carbon atoms, an optionally substituted divalent heteroaromatic group having 60 or less carbon atoms, or A plurality of groups selected from optionally substituted divalent C 60 or less aromatic hydrocarbon groups and optionally substituted divalent C 60 or less heteroaromatic groups is a group to which the group is linked,
Ar 2 is an optionally substituted monovalent aromatic hydrocarbon group having 60 or less carbon atoms, an optionally substituted monovalent heteroaromatic group having 60 or less carbon atoms, or A plurality of groups selected from optionally substituted monovalent aromatic hydrocarbon groups having 60 or less carbon atoms and optionally substituted monovalent heteroaromatic groups having 60 or less carbon atoms is a group to which the group is linked,
a2 represents an integer of 1 to 5; )

(In formula (4), an asterisk (*) represents a bond with formula (1),
L 3 is an optionally substituted divalent aromatic hydrocarbon group having 60 or less carbon atoms, an optionally substituted divalent heteroaromatic group having 60 or less carbon atoms, or A plurality of groups selected from optionally substituted divalent C 60 or less aromatic hydrocarbon groups and optionally substituted divalent C 60 or less heteroaromatic groups is a group to which the group is linked,
a3 represents an integer of 1 to 5; )
The aromatic compound according to claim 1 , wherein G1 is represented by the following formula (2).

(In formula (2), an asterisk (*) represents a bond with formula (1),
L 1 is an optionally substituted divalent aromatic hydrocarbon group having 60 or less carbon atoms, an optionally substituted divalent heteroaromatic group having 60 or less carbon atoms, or A plurality of groups selected from optionally substituted divalent C 60 or less aromatic hydrocarbon groups and optionally substituted divalent C 60 or less heteroaromatic groups is a group to which the group is linked,
Ar 1 is an optionally substituted monovalent aromatic hydrocarbon group having 60 or less carbon atoms, an optionally substituted monovalent heteroaromatic group having 60 or less carbon atoms, or A plurality of groups selected from optionally substituted monovalent aromatic hydrocarbon groups having 60 or less carbon atoms and optionally substituted monovalent heteroaromatic groups having 60 or less carbon atoms is a group to which the group is linked,
a 1 represents an integer of 0 to 5; )
3. The aromatic compound according to claim 2, wherein each of L 1 to L 3 is independently a phenyl group or a group in which a plurality of phenyl groups are linked.
4. The aromatic compound according to claim 2, wherein L 1 to L 3 are each independently a 1,3-phenylene group or a 1,4-phenylene group.
The aromatic compound according to any one of claims 1 to 4, which has a molecular weight of 1200 or more.
An organic electroluminescence device having an anode and a cathode on a substrate and an organic layer between the anode and the cathode,
The organic layer has a layer containing a material for an organic electroluminescent device,
An organic electroluminescence device, wherein the material for organic electroluminescence device is the aromatic compound according to any one of claims 1 to 5.
The organic electroluminescent device according to claim 6, wherein the layer containing the organic electroluminescent device material is a light-emitting layer.
A display device comprising the organic electroluminescence device according to claim 6 or 7.
A lighting device comprising the organic electroluminescent element according to claim 6 or 7.
A composition for an organic electroluminescence device, containing the aromatic compound according to any one of claims 1 to 5 and a solvent.
The composition for an organic electroluminescence device according to claim 10, further comprising a phosphorescent material and a charge transport material.
12. The composition for an organic electroluminescence device according to claim 11, wherein the charge transport material is a compound represented by the following formula (240) or a compound represented by the following formula (260).

(In formula (240),
Ar 611 and Ar 612 each independently represent an optionally substituted monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms,
R 611 and R 612 are each independently a deuterium atom, a halogen atom, or an optionally substituted monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms,
G represents a single bond or an optionally substituted divalent aromatic hydrocarbon group having 6 to 50 carbon atoms,
n 611 and n 612 are each independently an integer of 0-4. )

(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 It represents a branched and linked monovalent group.)
13. The organic compound according to claim 12, wherein each of Ar 611 and Ar 612 in the formula (240) is independently a monovalent group in which a plurality of optionally substituted benzene rings are bonded in a chain or branched manner. A composition for an electroluminescence device.
The organic according to claim 12 or 13, wherein R 611 and R 612 in the formula (240) are each independently an optionally substituted monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms. A composition for an electroluminescence device.
15. The composition for an organic electroluminescence device according to claim 12, wherein n 611 and n 612 in formula (240) are each independently 0 or 1.
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). 13. The composition for an organic electroluminescence device according to claim 12, wherein these structures may have the substituents.
A method for forming a thin film, comprising a step of forming a film from the composition for organic electroluminescent elements according to any one of claims 10 to 16 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:
A method for producing an organic electroluminescence device, comprising the step of forming the organic layer by a wet film-forming method using the composition for an organic electroluminescence device according to any one of claims 10 to 16.
The method for producing an organic electroluminescence device according to claim 18, wherein the organic layer is a light-emitting layer.
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, and a step of forming the light-emitting layer by a wet film-forming method using the composition for an organic electroluminescent device according to any one of claims 10 to 16. ,
forming the electron transport layer by a wet film-forming method using an electron transport layer composition containing an electron transport material and a solvent, in this order.
The method for producing an organic electroluminescence device according to claim 20, wherein the solvent contained in the electron transport layer composition is an alcohol solvent.