KR20240016969A - Aromatic compounds, organic electroluminescent devices, compositions, and methods for producing organic electroluminescent devices - Google Patents

Abstract

The object of the present invention is to provide an aromatic compound having excellent heat resistance, excellent solubility, excellent electron transport properties, and excellent thin film durability against alcohol solvents. The present invention provides an aromatic compound represented by the following formula (1), an organic electroluminescent device having an organic layer containing the aromatic compound as a material for an organic electroluminescent device, a composition for an organic electroluminescent device containing the aromatic compound and a solvent, and a method of manufacturing an organic electroluminescent device.

(In formula (1), G ¹ , G ² , and G ³ are each as defined in the specification.)

Description

Aromatic compounds, organic electroluminescent devices, compositions, and methods for producing organic electroluminescent devices

The present invention relates to 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, a display device having the organic electroluminescent device, and It relates to a lighting device, a composition containing the compound and solvent, a thin film formation method, and a manufacturing method of an organic electroluminescent device.

Recently, as a thin film type electroluminescent element, an organic electroluminescent element using an organic thin film has been developed instead of one using an inorganic material. An organic electroluminescent device (OLED) usually 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. Appropriate materials for each of these layers are being developed, and development of red, green, and blue luminous colors is in progress. In addition, research is underway on coating-type OLEDs, which have higher material utilization efficiency and can lower manufacturing costs compared to conventional deposition-type OLEDs.

In application-type OLEDs, there is a demand for longer lifespan of organic electroluminescent elements and for driving with lower power consumption. Various factors are thought to affect the lifespan and power consumption improvement of organic electroluminescent devices. For example, the thermal durability and crystallinity of the materials that make up organic electroluminescent devices have a significant influence on the lifespan. It is thought to have an effect.

In addition, in order to manufacture an organic electroluminescent element by a wet film forming method, all materials used must be dissolved in an organic solvent so that they can be used as ink. If the material used has poor solubility, there is a possibility that the material may deteriorate before use because operations such as heating for a long time are required. Additionally, if a uniform state cannot be maintained in the solution state for a long time, material may precipitate from the solution, making film formation using an inkjet device or the like impossible. Materials used in the wet film formation method are required to have solubility in two senses: to dissolve quickly in an organic solvent, and to maintain a uniform state without precipitating after dissolution.

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

[Formula 1]

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

[Formula 2]

International Publication No. 2012/137958 US Patent No. 9960363 Specification

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

The present invention was made in consideration of the above-described conventional circumstances, and its object is to provide an aromatic compound having excellent heat resistance, excellent solubility, excellent electron transport, and excellent thin film durability against alcohol solvents.

In addition, the present invention provides 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 thin film formation method, and a manufacturing method of the organic electroluminescent device. The task is to do it.

In addition, in this specification, “alcohol solvent” may be referred to as “alcohol-based solvent” or “alcohol-based solvent.”

As a result of intensive studies, the present inventors have found that the above problems can be solved by using an aromatic compound having a triazine and 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).

[Formula 3]

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

[Formula 4]

(In equation (3), asterisk (*) indicates combination with equation (1),

L ² is a divalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, a divalent heteroaromatic group having 60 carbon atoms or less which may have a substituent, or a divalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, and It is a group in which a plurality of groups selected from divalent heteroaromatic groups having 60 carbon atoms or less which may have a substituent are connected,

Ar ² is a monovalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, a monovalent heteroaromatic group having 60 carbon atoms or less which may have a substituent, or a monovalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent; It is a group in which a plurality of groups selected from monovalent heteroaromatic groups having 60 or less carbon atoms that may have a substituent are connected,

a ² represents an integer from 1 to 5.)

[Formula 5]

(In equation (4), asterisk (*) indicates combination with equation (1),

L ³ is a divalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, a divalent heteroaromatic group having 60 carbon atoms or less which may have a substituent, or a divalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, and It is a group in which a plurality of groups selected from divalent heteroaromatic groups having 60 carbon atoms or less, which may have a substituent, are connected,

a ³ represents an integer from 1 to 5.)

＜2＞

The aromatic compound described in <1>, wherein G ¹ is represented by the following formula (2).

[Formula 6]

(In equation (2), asterisk (*) indicates combination with equation (1),

L ¹ is a divalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, a divalent heteroaromatic group having 60 carbon atoms or less which may have a substituent, or a divalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, and It is a group in which a plurality of groups selected from divalent heteroaromatic groups having 60 carbon atoms or less which may have a substituent are connected,

Ar ¹ is a monovalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, a monovalent heteroaromatic group having 60 carbon atoms or less which may have a substituent, or a monovalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent; It is a group in which a plurality of groups selected from monovalent heteroaromatic groups having 60 or less carbon atoms that may have a substituent are connected,

a ¹ represents an integer from 0 to 5.)

＜3＞

The aromatic compound according to <2>, wherein L ¹ to L ³ are each independently a phenyl group or a group containing a plurality of phenyl groups linked together.

＜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 electroluminescent 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 electroluminescent device, wherein the material for the organic electroluminescent device is an 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 electroluminescent device containing the aromatic compound and solvent according to any one of <1> to <5>.

＜11＞

Additionally, the composition for an organic electroluminescent device according to <10>, which contains a phosphorescent material and a charge transport material.

＜12＞

The composition for an organic electroluminescent device according to <11>, wherein the charge transport material is a compound represented by the following formula (240) or a compound represented by the following formula (260).

[Formula 7]

(In equation (240),

Ar ⁶¹¹ and Ar ⁶¹² each independently represent a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent,

R ⁶¹¹ and R ⁶¹² are each independently a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent,

G represents a single bond or a divalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent,

n ⁶¹¹ and n ⁶¹² are each independently integers from 0 to 4.)

[Formula 8]

(In formula (260), Ar ²¹ to Ar ³⁵ each independently represent a hydrogen atom, a phenyl group which may have a substituent, or a monovalent group of 2 to 10 phenyl groups which may have a substituent, unbranched or branchedly connected. )

＜13＞

The composition for an organic electroluminescent device according to <12>, wherein Ar ⁶¹¹ and Ar ⁶¹² in the formula (240) are each independently a monovalent group in which a plurality of benzene rings, which may have a substituent, are bonded in a chained or branched manner.

＜14＞

The composition for an organic electroluminescent device according to <12> or <13>, wherein R ⁶¹¹ and R ⁶¹² in the formula (240) are each independently a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent.

＜15＞

The composition for an organic electroluminescent device according to any one of <12> to <14>, wherein n ⁶¹¹ and n ⁶¹² in the 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, and structures selected from the following formulas (261-1) to (261-9), and these structures are The composition for an organic electroluminescent device according to <12>, which may have the above substituent.

[Formula 9]

＜17＞

A thin film forming method comprising the step of forming the composition for an organic electroluminescent device according to any one of <10> to <16> into a film by a wet film forming method.

＜18＞

A method of manufacturing an organic electroluminescent device having an anode and a cathode on a substrate and an organic layer between the anode and the cathode, comprising:

A method for producing an organic electroluminescent device, including the step of 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 electroluminescent device according to <18>, wherein the organic layer is a light-emitting layer.

＜20＞

A method of manufacturing an organic electroluminescent device having an anode and a cathode on a substrate and an organic layer between the anode and the cathode, comprising:

The organic layer includes a light-emitting layer and an electron transport layer,

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 <10> to <16>;

A method for producing an organic electroluminescent device, comprising the step of forming the electron transport layer by a wet film forming method using a composition for an electron transport layer containing an electron transport material and a solvent in this order.

＜21＞

The method for producing an organic electroluminescent device according to <20>, wherein the solvent contained in the composition for the electron transport layer is an alcohol-based 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 against alcohol solvents in a thin film.

Furthermore, 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 thin film formation method, and a method for producing the organic electroluminescent device. can be provided.

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

Below, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments and can be implemented with various modifications within the scope of the gist.

In the present invention, “may have 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).

[Formula 10]

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

[Formula 11]

(In equation (3), asterisk (*) indicates combination with equation (1),

L ² is a divalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, a divalent heteroaromatic group having 60 carbon atoms or less which may have a substituent, or a divalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, and It is a group in which a plurality of groups selected from divalent heteroaromatic groups having 60 carbon atoms or less which may have a substituent are connected,

Ar ² is a monovalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, a monovalent heteroaromatic group having 60 carbon atoms or less which may have a substituent, or a monovalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent; It is a group in which a plurality of groups selected from monovalent heteroaromatic groups having 60 or less carbon atoms that may have a substituent are connected,

a ² represents an integer from 1 to 5.)

[Formula 12]

(In equation (4), asterisk (*) indicates combination with equation (1),

L ³ is a divalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, a divalent heteroaromatic group having 60 carbon atoms or less which may have a substituent, or a divalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, and It is a group in which a plurality of groups selected from divalent heteroaromatic groups having 60 carbon atoms or less which may have a substituent are connected,

a ³ represents an integer from 1 to 5.)

From the viewpoint of electron transport properties, G ¹ is preferably represented by the following formula (2).

[Formula 13]

(In equation (2), asterisk (*) indicates combination with equation (1),

L ¹ is a divalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, a divalent heteroaromatic group having 60 carbon atoms or less which may have a substituent, or a divalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, and It is a group in which a plurality of groups selected from divalent heteroaromatic groups having 60 carbon atoms or less which may have a substituent are connected,

Ar ¹ is a monovalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, a monovalent heteroaromatic group having 60 carbon atoms or less which may have a substituent, or a monovalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent; It is a group in which a plurality of groups selected from monovalent heteroaromatic groups having 60 or less carbon atoms that may have a substituent are connected,

a ¹ represents an integer from 0 to 5.)

In the present invention, the mechanism of action through which effective effects are obtained is estimated 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, the triazine skeleton and the spirobifluorene structure are bonded through a structure larger than that of biphenyl, so that steric hindrance due to the spirobifluorene structure can be suppressed and the electron transport property is high. Additionally, the aromatic compound of the present invention has high solubility because the spirobifluorene structure represented by formula (4) has a biphenyl group bonded at the meta position. Since the compound of the present invention has a large molecular weight and has 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 easily localized in the spirobifluorene structure represented by formula (3). Durability can be improved.

By using the aromatic compound of the present invention, an organic electroluminescent device that has excellent driving stability and can be driven at low driving voltage and high efficiency can be easily provided.

The organic electroluminescent device of the present invention containing the aromatic compound of the present invention has excellent electrochemical stability and high efficiency due to low driving voltage. Therefore, the organic electroluminescent device of the present invention can be used as a light source that takes advantage of the characteristics of 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 surface light emitter (for example, It can be used as a light source for copiers, backlight light sources for liquid crystal displays and instruments), display boards, signs, etc., and its technical value is great.

＜Ar ¹ , Ar ² ＞

Ar ¹ and Ar ² each independently represent a monovalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, a monovalent heteroaromatic group having 60 carbon atoms or less which may have a substituent, or a monovalent carbon number which may have a substituent. It represents a group in which a plurality of groups selected from aromatic hydrocarbon groups with 60 or less carbon atoms and monovalent heteroaromatic groups with 60 or less carbon atoms which may have a substituent are connected.

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, benzoanthracene ring, perylene ring, biphenyl ring, Or a monovalent group of a terphenyl ring can be mentioned.

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, and imidazole ring. , oxadiazole ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thieno Furan ring, benzoisoxazole ring, benzoisothiazole ring, benzoimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, cinnoline ring, quinoxaline A monovalent group of a ring, a perimidine ring, a quinazoline ring, a quinazolinone ring, or an azulene ring may be mentioned.

From the viewpoint of solubility and durability of the compound, a phenyl group, a group with multiple phenyl groups connected, or a naphthyl group is preferable, and a phenyl group or a group with multiple phenyl groups connected is more preferable.

＜L ¹ , L ² , L ³ ＞

L ¹ , L ² , and L ³ are each independently a divalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, a divalent heteroaromatic group having 60 carbon atoms or less which may have a substituent, or It represents a group in which a plurality of groups selected from a divalent aromatic hydrocarbon group with 60 or less carbon atoms and a divalent heteroaromatic group with 60 or less carbon atoms which may have a substituent are connected.

Examples of divalent aromatic hydrocarbon groups having 60 or less carbon atoms include divalent groups of benzene ring, naphthalene ring, anthracene ring, tetraphenylene ring, phenanthrene ring, chrysene ring, pyrene ring, benzoanthracene ring, or perylene ring. I can hear it.

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, and imidazole ring. , oxadiazole ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thieno Furan ring, benzoisoxazole ring, benzoisothiazole ring, benzoimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, cinnoline ring, quinoxaline A divalent group of a ring, a perimidine ring, a quinazoline ring, a quinazolinone ring, or an azulene ring may be mentioned.

From the viewpoint of solubility and durability of the compound, a phenyl group, a group with multiple phenyl groups connected, or a naphthyl group is preferable, and a phenyl group or a group with multiple phenyl groups connected is more preferable. Among these, 1,3-phenylene group or 1,4-phenylene group is more preferable.

^{＜a 1 to a 3 ＞}

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, a ¹ and a ³ are preferably 3 or less, more preferably 2 or less, particularly 1 or less, and a ² is preferably 4 or less, and even more preferably 3 or less.

When a ¹ to a ³ is 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 has a partial structure represented by the following formula (11) or a portion represented by the following formula (12) from the viewpoint of solubility and durability of the compound. It is preferable to have at least one partial structure selected from a structure and a partial structure represented by the following formula (13).

[Formula 14]

In each of the above formulas (11) to (13), * represents a bond to an adjacent structure or a hydrogen atom, and at least one of the two * represents a bonding position to 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 a partial structure represented by formula (11) or a partial structure represented by formula (12).

More preferably, (L ¹ ) _a1 , (L ² ) _a2 , and (L ³ ) _a3 each have at least a partial structure represented by formula (11) or a 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 15]

More preferably, the formula (12) is the following formula (12-3).

[Formula 16]

In addition, in the case where it has the partial structure represented by formula (11) and the partial structure represented by formula (12), it contains a plurality of structures selected from 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 formula (14) to the following formula (18).

[Formula 17]

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

[Formula 18]

Moreover, more preferably, at least one of (L ¹ ) _a1 , (L ² ) _a2 , and (L ³ ) _a3 has at least a partial structure represented by formula (14) or a partial structure represented by formula (15). .

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

[Formula 19]

More preferably, the formula (14) is the following formula (14-3).

[Formula 20]

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

[Formula 21]

More preferably, the formula (15) is the following formula (15-3).

[Formula 22]

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

[Formula 23]

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

[Formula 24]

Moreover, as a structure containing the partial structure represented by Formula (13), 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).

[Formula 25]

In each of the above formulas (14) to (20), * represents a bond to an adjacent structure or a hydrogen atom, and at least one of the two * represents a bonding position to an adjacent structure.

Among formulas (14) to (20), formula (14-3) and formula (15-3) are preferable, and formula (14-3) is more preferable.

＜Substituent＞

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

[Substituent group Z]

The substituent group Z includes alkyl group, alkenyl group, alkynyl group, alkoxy group, aryloxy group, alkoxycarbonyl group, acyl group, halogen atom, haloalkyl group, alkylthio group, arylthio group, silyl group, siloxy group, cyano group, and ar. Examples include an alkyl group, an aromatic hydrocarbon group, or a heteroaromatic group.

Alkyl groups include, for example, methyl group, ethyl group, branched, straight-chain or cyclic propyl group, branched, straight-chain or cyclic butyl group, branched, straight-chain or cyclic pentyl group, branched, straight-chain or cyclic group. A cyclic 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 has 1 or more carbon atoms, preferably Examples of linear, branched, or cyclic alkyl groups include 4 or more, usually 24 or less, preferably 10 or less. From the viewpoint of the stability of the compound, a methyl group, an ethyl group, a branched, straight-chain or cyclic propyl group, and a branched, straight-chain or cyclic butyl group are preferred, and branched propyl groups are particularly preferred.

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

Examples of the alkynyl group include alkynyl groups such as an ethynyl group, where the carbon number is usually 2 or more and usually 24 or less, preferably 12 or less.

Examples of the alkoxy group include alkoxy groups such as methoxy groups and ethoxy groups, where the number of carbon atoms is usually 1 or more and usually 24 or less, preferably 12 or less.

Examples of the aryloxy group include an aryloxy group or heteroaryl group, such as a phenoxy group, naphthoxy group, or pyridyloxy group, having a carbon number of usually 4 or more, preferably 5 or more, and usually 36 or less, preferably 24 or less. Oxygen groups can be mentioned.

Examples of the alkoxycarbonyl group include alkoxycarbonyl groups such as methoxycarbonyl group and ethoxycarbonyl group, where the carbon number is usually 2 or more and usually 24 or less, preferably 12 or less.

Examples of the acyl group include acyl groups such as acetyl group and benzoyl group, which usually have 2 or more carbon atoms and usually 24 or less carbon atoms, preferably 12 or less carbon atoms.

Examples of the halogen atom include halogen atoms such as a fluorine atom and a chlorine atom.

Examples of the haloalkyl group include haloalkyl groups such as trifluoromethyl group, which usually have 1 or more carbon atoms and usually 12 or less carbon atoms, preferably 6 or less carbon atoms.

Examples of the alkylthio group include alkylthio groups such as methylthio groups and ethylthio groups, where the carbon number is usually 1 or more and usually 24 or less, preferably 12 or less.

Examples of the arylthio group include arylthio groups such as phenylthio group, naphthylthio group, and pyridylthio group, which have a carbon number of usually 4 or more, preferably 5 or more, and usually 36 or less, preferably 24 or less. there is.

Examples of the silyl group include silyl groups such as trimethylsilyl group and triphenylsilyl group, which have a carbon number of usually 2 or more, preferably 3 or more, and usually 36 or less, preferably 24 or less.

Examples of the siloxy group include siloxy groups such as trimethylsiloxy group and triphenylsiloxy group, which have a carbon number of usually 2 or more, preferably 3 or more, and usually 36 or less, preferably 24 or less.

Examples of aralkyl groups include benzyl group, 2-phenylethyl group, 2-phenylpropyl-2-yl group, 2-phenylbutyl-2-yl group, 3-phenylpentyl-3-yl group, and 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. Examples include aralkyl groups where the carbon number is usually 7 or more, preferably 9 or more, and usually 30 or less, preferably 18 or less, and more preferably 10 or less.

The aromatic hydrocarbon group usually has 6 or more carbon atoms, such as a benzene ring, naphthalene ring, anthracene ring, tetraphenylene ring, phenanthrene ring, chrysene ring, pyrene ring, benzoanthracene ring, or perylene ring. , usually 30 or less, preferably 18 or less, more preferably 10 or less aromatic hydrocarbon groups.

Heteroaromatic groups include, for example, furan ring, benzofuran ring, dibenzofuran ring, thiophene ring, benzothiophene ring, dibenzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, and oxadiazole. ring, indole ring, carbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furofuran ring, thienofuran ring, benzoyl ring. Soxazole ring, benzoisothiazole ring, benzoimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, cinnoline ring, quinoxaline ring, perimidine Examples include heteroaromatic groups having a carbon number of usually 4 or more, usually 30 or less, preferably 18 or less, and more preferably 12 or less, such as a ring, quinazoline ring, quinazolinone ring, or azulene ring.

Among the substituent group Z, an alkyl group, an alkoxy group, an aralkyl group, and an aromatic hydrocarbon group are preferable, and more preferably, an alkyl group with 10 or less carbon atoms, an aralkyl group with 30 or less carbon atoms, and an aromatic hydrocarbon group with 30 or less carbon atoms, More preferably, it is an aromatic hydrocarbon group with 30 or less carbon atoms, and especially preferably, it is a group that does not have a substituent.

In addition, each substituent in the above substituent group Z may further have a substituent. As these additional substituents, the same ones as the above substituents (substituent group Z) can be used. It is preferable that the substituents of the substituent group Z do not have additional substituents from the viewpoint of charge transport properties.

＜Molecular weight＞

The molecular weight of the aromatic compound of the present invention is preferably 1000 or more, more preferably 1100 or more, most preferably 1200 or more, preferably 5000 or less, further preferably 4000 or less, and especially preferably 3000. or less, and most preferably 2000 or less.

＜Specific example＞

Specific examples of the aromatic compound of the present invention are shown below, but the present invention is not limited to these.

[Formula 26]

[Formula 27]

[Formula 28]

[Formula 29]

[Formula 30]

[Formula 31]

[Formula 32]

[Formula 33]

[Formula 34]

[Formula 35]

[Formula 36]

[Formula 37]

[Formula 38]

[Formula 39]

[Formula 40]

[Formula 41]

[Formula 42]

[Formula 43]

[Formula 44]

[Formula 45]

[Formula 46]

[Formula 47]

[Formula 48]

[Formula 49]

＜Method for producing aromatic compounds＞

The aromatic compound of the present invention can be produced, for example, according to the method described in the Examples.

[Uses of aromatic compounds]

The aromatic compound of the present invention is a material for an organic electroluminescent device, and is preferably used in an organic layer of an organic electroluminescent device, and the organic layer is preferably a light emitting layer. An organic electroluminescent device may 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 a 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 a wet film forming 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 an organic electroluminescent device.

[Composition]

When forming an organic layer containing an aromatic compound of the present invention by a wet film forming method, a composition containing at least an aromatic compound represented by the above formula (1) and a solvent (hereinafter sometimes referred to as “organic solvent”) is wet-processed. Make a tabernacle. That is, the composition of the present invention contains at least an aromatic compound and an organic solvent represented by the above formula (1).

The composition of the present invention is preferably used as a composition for organic electroluminescent devices for forming organic electroluminescent devices.

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

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

＜Organic solvent＞

The organic solvent contained in the composition of the present invention is a volatile liquid component used to form a 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 as the solute and the light-emitting 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, dichlorobenzene, and trichlorobenzene; 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetol, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2, Aromatic ethers such as 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 ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol-1-monomethyl ether acetate (PGMEA); etc. can be mentioned.

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

These organic solvents may be used individually, 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, and more preferably 330°C or lower. If the boiling point of the organic solvent is below this range, film formation stability may decrease due to solvent evaporation from the composition during wet film formation. If the boiling point of the organic solvent exceeds this range, during wet film formation, film formation stability may decrease due to residual solvent after film formation.

In particular, a uniform coating film can be produced by combining two or more of the above organic solvents with a boiling point of 150°C or higher. It is thought that if there is one or less organic solvents with a boiling point of 150°C or higher, a uniform film may not be formed during application.

＜Luminescent material＞

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

As the luminescent material, known materials can be applied, and fluorescent luminescent materials or phosphorescent luminescent materials can be used alone or in combination, but from the viewpoint of internal quantum efficiency, phosphorescent luminescent materials are preferred.

(phosphorescent material)

A phosphorescent material refers to a material that emits light from a triplet excited state. For example, metal complex compounds having Ir, Pt, Eu, etc. are representative examples, and it is preferable that the material structure includes a metal complex.

Among metal complexes, it is a phosphorescent organic metal complex that emits light via a triplet state, and is a long-periodic periodic table (hereinafter, unless otherwise specified, the term “periodic table” refers to the long-period periodic table). A Werner-type complex or organometallic complex compound containing a metal selected from Groups 7 to 11 as a central metal can be mentioned. As such a phosphorescent material, a compound represented by the formula (201) below or a compound represented by the formula (205) described later is preferable, and more preferably, it is a compound represented by the formula (201) below.

[Formula 50]

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

Ring A1 represents an aromatic hydrocarbon ring structure that may have a substituent or an aromatic heterocyclic ring structure that may have a substituent.

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

R ²⁰¹ and R ²⁰² each independently represent a structure represented by the above formula (202), and “*” indicates bonding to ring A1 or ring A2. R ²⁰¹ and R ²⁰² may be the same or different, and when two or more R ²⁰¹ and R ²⁰² each exist, they may be the same or different.

Ar ²⁰¹ and Ar ²⁰³ each independently represent an aromatic hydrocarbon ring structure that may have a substituent, or an aromatic heterocyclic ring structure that may have a substituent.

Ar ²⁰² represents an aromatic hydrocarbon ring structure that may have a substituent, an aromatic heterocyclic ring structure that may have a substituent, or an aliphatic hydrocarbon structure that may have a substituent.

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 bond with 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 that together with B ²⁰¹ and B ²⁰² constitutes a bidentate ligand. When there is a plurality of B ²⁰¹ -L ²⁰⁰ -B ²⁰² , they may be the same or different.

i1 and i2 each independently represent an integer between 0 and 12.

i3 is an integer greater than or equal to 0, with the upper limit being the number that can be replaced by Ar ²⁰² .

j is an integer greater than or equal to 0, with the upper limit being the number that can be replaced with Ar ²⁰¹ .

k1 and k2 are each independently an integer of 0 or more that sets the upper limit on the number of rings that can be substituted for ring A1 and ring A2.

m is an integer from 1 to 3.

The aromatic hydrocarbon ring in ring A1 is preferably an aromatic hydrocarbon ring having 6 to 30 carbon atoms, and specifically includes a benzene ring, a naphthalene ring, an anthracene ring, a triphenylyl ring, an acenaphthene ring, a fluoranthene ring, Fluorene rings are preferred.

The aromatic heterocycle in ring A1 is preferably an aromatic heterocycle with 3 to 30 carbon atoms containing any of a nitrogen atom, an oxygen atom, or a sulfur atom as a heteroatom, and more preferably a furan ring or a benzoyl ring. They are a furan ring, a thiophene ring, and a benzothiophene ring.

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

The aromatic heterocycle in ring A2 is preferably an aromatic heterocycle with 3 to 30 carbon atoms containing any of 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, benzooxazole ring, benzoimidazole ring, quinoline ring, isoquinoline. ring, quinoxaline ring, quinazoline ring, naphthyridine ring, phenanthridine ring,

More preferably, they are a pyridine ring, a pyrazine ring, a pyrimidine ring, an imidazole ring, a benzothiazole ring, a benzoxazole ring, a quinoline ring, an isoquinoline ring, a quinoxaline ring, and a quinazoline ring,

More preferably, they are a pyridine ring, an imidazole ring, a benzothiazole ring, a quinoline ring, an isoquinoline ring, a quinoxaline ring, and a quinazoline ring,

Most preferably, they are a pyridine ring, an imidazole ring, a benzothiazole ring, a quinoline ring, a quinoxaline ring, and a quinazoline ring.

A preferred combination of ring A1 and ring A2 is expressed as (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 can be selected arbitrarily, but are preferably one or more types of substituents selected from the substituent group S described later.

If any of Ar ²⁰¹ , Ar ²⁰² , and Ar ²⁰³ is an aromatic hydrocarbon ring structure that may have a substituent,

The aromatic hydrocarbon ring structure is preferably an aromatic hydrocarbon ring having 6 to 30 carbon atoms,

Specifically, a benzene ring, a 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 is preferred, and the benzene ring is most preferred.

When Ar ²⁰¹ , Ar ²⁰² , or Ar ²⁰³ is a fluorene ring that may have a substituent, the 9th and 9' positions of the fluorene ring preferably have a substituent or are bonded to an adjacent structure.

When Ar ²⁰¹ , Ar ²⁰² , or Ar ²⁰³ is a benzene ring that may have a substituent, it is preferable that at least one benzene ring is bonded to an adjacent structure at the ortho or meta position, and at least one benzene ring is It is more preferable that it is bonded to an adjacent structure at the meta position.

If any of Ar ²⁰¹ , Ar ²⁰² , and Ar ²⁰³ is an aromatic heterocyclic ring structure that may have a substituent,

The aromatic heterocyclic ring structure is preferably an aromatic heterocycle with 3 to 30 carbon atoms containing any of 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, benzoimidazole ring, quinoline ring, isoquinoline. ring, quinoxaline ring, quinazoline ring, naphthyridine ring, phenanthridine ring, carbazole ring, dibenzofuran ring, dibenzothiophene ring,

More preferably, they are a pyridine ring, a pyrimidine ring, a triazine ring, a carbazole ring, a dibenzofuran ring, and a dibenzothiophene ring.

When Ar ²⁰¹ , Ar ²⁰² , or Ar ²⁰³ is a carbazole ring that may have a substituent, the N position of the carbazole ring preferably has a substituent or is bonded to an adjacent structure.

When Ar ²⁰² is an aliphatic hydrocarbon structure that may have a substituent,

The aliphatic hydrocarbon structure is an aliphatic hydrocarbon structure having a straight chain, branched chain, or cyclic structure,

Preferably, it is an aliphatic hydrocarbon having 1 to 24 carbon atoms,

More preferably, it is an aliphatic hydrocarbon having 1 to 12 carbon atoms,

More preferably, it is an aliphatic hydrocarbon having 1 to 8 carbon atoms.

i1 and i2 are each independently, preferably an integer of 1 to 12, more preferably an integer of 1 to 8, and still more preferably an integer of 1 to 6. Within this range, improvement in solubility and charge transport are expected.

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

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

k1 and k2 preferably represent an integer of 0 to 3, more preferably an integer of 1 to 3, further preferably 1 or 2, and especially preferably 1.

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

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

＜Substituent group S＞

- An alkyl group, preferably an alkyl group with 1 to 20 carbon atoms, more preferably an alkyl group with 1 to 12 carbon atoms, further preferably an alkyl group with 1 to 8 carbon atoms, particularly preferably an alkyl group with 1 to 6 carbon atoms.

- An alkoxy group, preferably an alkoxy group with 1 to 20 carbon atoms, more preferably an alkoxy group with 1 to 12 carbon atoms, and even more preferably an alkoxy group with 1 to 6 carbon atoms.

An aryloxy group, preferably an aryloxy group with 6 to 20 carbon atoms, more preferably an aryloxy group with 6 to 14 carbon atoms, even more preferably an aryloxy group with 6 to 12 carbon atoms, particularly preferably with 6 carbon atoms. Aryloxy group.

-Heteroaryloxy group, preferably a heteroaryloxy group having 3 to 20 carbon atoms, more preferably a heteroaryloxy group having 3 to 12 carbon atoms.

-Alkylamino group, preferably an alkylamino group having 1 to 20 carbon atoms, more preferably an alkylamino group having 1 to 12 carbon atoms.

- Arylamino group, preferably an arylamino group with 6 to 36 carbon atoms, more preferably an arylamino group with 6 to 24 carbon atoms.

- An aralkyl group, preferably an aralkyl group with 7 to 40 carbon atoms, more preferably an aralkyl group with 7 to 18 carbon atoms, even more preferably an aralkyl group with 7 to 12 carbon atoms.

- A heteroaralkyl group, preferably a heteroaralkyl group with 7 to 40 carbon atoms, more preferably a heteroaralkyl group with 7 to 18 carbon atoms.

An alkenyl group, preferably an alkenyl group with 2 to 20 carbon atoms, more preferably an alkenyl group with 2 to 12 carbon atoms, even more preferably an alkenyl group with 2 to 8 carbon atoms, particularly preferably an alkenyl group with 2 to 6 carbon atoms. .

- An alkynyl group, preferably an alkynyl group with 2 to 20 carbon atoms, more preferably an alkynyl group with 2 to 12 carbon atoms.

An aryl group, preferably an aryl group with 6 to 30 carbon atoms, more preferably an aryl group with 6 to 24 carbon atoms, even more preferably an aryl group with 6 to 18 carbon atoms, particularly preferably an aryl group with 6 to 14 carbon atoms. .

A heteroaryl group, preferably a heteroaryl group with 3 to 30 carbon atoms, more preferably a heteroaryl group with 3 to 24 carbon atoms, even more preferably a heteroaryl group with 3 to 18 carbon atoms, particularly preferably 3 to 30 carbon atoms. 14 heteroaryl group.

- An alkylsilyl group, preferably an alkylsilyl group in which the alkyl group has 1 to 20 carbon atoms, more preferably an alkylsilyl group in which the alkyl group has 1 to 12 carbon atoms.

· 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.

· Arylcarbonyl group, preferably an arylcarbonyl group having 7 to 20 carbon atoms.

·Hydrogen atom, deuterium atom, fluorine atom, cyano group, or -SF ₅ .

In the above group, one or more hydrogen atoms may be substituted with a fluorine atom, or one or more hydrogen atoms may be substituted with a deuterium atom.

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

(Preferred group in substituent group S)

Among these substituent groups S,

Preferably, an alkyl group, alkoxy group, aryloxy group, arylamino group, aralkyl group, alkenyl group, aryl group, heteroaryl group, alkylsilyl group, arylsilyl group, and one or more hydrogen atoms of these groups are substituted with a fluorine atom. group, fluorine atom, cyano group, or -SF ₅ ,

More preferably, it is an alkyl group, arylamino group, aralkyl group, alkenyl group, aryl group, heteroaryl group, a group in which at least one hydrogen atom of these groups is replaced with a fluorine atom, a fluorine atom, a cyano group, or -SF ₅ ,

More preferably, they are 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 an alkyl group, an arylamino group, an aralkyl group, an alkenyl group, an aryl group, and a heteroaryl group,

Most preferably, they are an alkyl group, arylamino group, aralkyl group, aryl group, and heteroaryl group.

These substituent groups S may further have a substituent selected from the substituent group S as a substituent. The preferred groups, more preferred groups, further preferred groups, particularly preferred groups, and most preferred groups of the substituents that may be included are the same as the preferred groups in substituent group S.

(Preferred structure of equation (201))

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

In the structure with a group connected to the benzene ring,

Ar ²⁰¹ is a benzene ring structure, i1 is 1 to 6, and at least one benzene ring is bonded to an adjacent structure at the ortho or meta position.

This structure is expected to improve solubility and charge transport properties.

In the structure having an aromatic hydrocarbon group or an aromatic heterocyclic group to which an alkyl group or aralkyl group is bonded to ring A1 or ring A2,

Ar ²⁰¹ is an aromatic hydrocarbon structure or an aromatic heterocyclic ring structure, i1 is 1 to 6,

Ar ²⁰² is an aliphatic hydrocarbon structure, i2 is 1 to 12, preferably 3 to 8,

Ar ²⁰³ is a benzene ring structure, and i3 is 0 or 1.

In the case of this structure, Ar ²⁰¹ is preferably the aromatic hydrocarbon structure described above, more preferably a structure in which 1 to 5 benzene rings are linked, and even more preferably one benzene ring.

This structure is expected to improve solubility and charge transport properties.

In the structure where a dendron is bonded 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 solubility and charge transport properties.

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

[Formula 51]

R ²¹¹ , R ²¹² , and R ²¹³ represent a substituent.

The substituent is not particularly limited, but is preferably a group selected from the above substituent group S.

[Formula 52]

Ring B3 represents an aromatic heterocyclic ring structure containing a nitrogen atom and which may have a substituent.

Ring B3 is preferably a pyridine ring.

The substituent that ring B3 may have is not particularly limited, but is preferably a group selected from the above substituent group S.

The phosphorescent material represented by formula (201) is not particularly limited, but specifically includes the following structures.

Additionally, Me means a methyl group and Ph means a phenyl group.

[Formula 53]

[Formula 54]

[Formula 55]

[Formula 56]

[Formula 57]

[Formula 58]

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

[Formula 59]

In formula (205), M ² represents a metal and T represents a carbon atom or a nitrogen atom. R ⁹² to R ⁹⁵ each independently represent a substituent. However, when T is a nitrogen atom, R ⁹⁴ and R ⁹⁵ do not exist.

In formula (205), M ² represents a metal. Specific examples include metals selected from groups 7 to 11 of the periodic table. Among these, ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, or gold are preferred, and divalent metals such as platinum and palladium are particularly preferred.

Moreover, in formula (205), R ⁹² and R ⁹³ are each independently hydrogen atom, halogen atom, alkyl group, aralkyl group, alkenyl group, cyano group, amino group, acyl group, alkoxycarbonyl group, carboxyl group, alkoxy group, It represents an alkylamino group, aralkylamino group, haloalkyl group, hydroxyl group, aryloxy group, aromatic hydrocarbon group, or aromatic heterocyclic group.

In addition, when T is a carbon atom, R ⁹⁴ and R ⁹⁵ each independently represent a substituent represented by the same example as R ⁹² and R ⁹³ . Additionally, when T is a nitrogen atom, R ⁹⁴ or R ⁹⁵ directly bonded to T does not exist.

In addition, R ⁹² to R ⁹⁵ may further have a substituent. As the substituent, the above substituents exemplified as R ⁹² and R ⁹³ can be used. Additionally, any two or more groups among R ⁹² to R ⁹⁵ may be connected to each other to form a ring.

(Molecular Weight)

The molecular weight of the phosphorescent material is preferably 5000 or less, more preferably 4000 or less, and particularly preferably 3000 or less. Additionally, the molecular weight of the phosphorescent material is usually 1000 or more, preferably 1100 or more, and more preferably 1200 or more. It is believed that within this molecular weight range, the phosphorescent materials do not aggregate and are uniformly mixed with the compound of the present invention and/or other charge transport materials, thereby obtaining a light emitting layer with high luminescence efficiency.

The molecular weight of the phosphorescent material has a high Tg, melting point, and decomposition temperature, and the heat resistance of the phosphorescent material and the formed light-emitting layer is excellent, and it is resistant to deterioration of film quality or thermal decomposition of the material due to gas generation, recrystallization, and migration of molecules. A larger size is preferable because it is difficult for an accompanying increase in impurity concentration to occur. On the other hand, the molecular weight of the phosphorescent material is preferably small to facilitate purification of the organic compound.

[Charge transport material]

When the composition of the present invention is a composition for forming a light emitting layer, in addition to the aromatic compound of the present invention, it is preferable to contain a charge transport material other than the aromatic compound of the present invention as an additional host material.

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

Skeletons with excellent charge transport properties include, specifically, aromatic structure, aromatic amine structure, triarylamine structure, dibenzofuran structure, naphthalene structure, phenanthrene structure, phthalocyanine structure, porphyrin structure, thiophene structure, benzylphenyl structure, Fluorene structure, quinacridone structure, triphenylene structure, carbazole structure, pyrene structure, anthracene structure, phenanthroline structure, quinoline structure, pyridine structure, pyrimidine structure, triazine structure, oxadiazole structure or imidazole structure. structure, etc.

In the composition of the present invention, since the compound represented by the above formula (1) functions as an electron transport material, it is preferable to further include a hole transport material as a charge transport material. A hole transport material is a compound having a structure excellent in hole transport, and among the skeletons excellent in charge transport, a carbazole structure, a dibenzofuran structure, a triarylamine structure, a naphthalene structure, a phenanthrene structure, or a pyrene structure has hole transport properties. It is preferable as an excellent structure, 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 transport 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, a compound having two or more condensed ring structures of three or more rings, or a compound having at least one condensed ring of five or more rings. It is more desirable. By using these compounds, the rigidity of the molecules increases, making it easier to obtain the effect of suppressing the degree of molecular movement in response to heat. In addition, it is preferable that the condensed ring of three or more rings and the condensed ring of five or more rings have an aromatic hydrocarbon ring or an aromatic heterocycle from the viewpoint of charge transport properties and durability of the material.

Condensed ring structures of three or more rings specifically include anthracene structure, phenanthrene structure, pyrene structure, chrysene structure, naphthacene structure, triphenylene structure, fluorene structure, benzofluorene structure, and indenofluorene structure. , indolofluorene structure, carbazole structure, indenocarbazole structure, indolocarbazole structure, dibenzofuran structure, dibenzothiophene structure, etc.

In terms of charge transport and solubility, it consists 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. At least one selected from the group is preferable, and from the viewpoint of durability against charge, a carbazole structure or an indolocarbazole structure is more preferable.

Among the charge transport materials used as the host material of the light-emitting layer, a material that adjusts charge transport properties is preferably a compound represented by the formula (260) described later, which is a compound having a structure in which multiple benzene rings are connected. It is believed that by including this compound as a host material, the excitons generated within the light-emitting layer efficiently recombine to increase luminous efficiency. Additionally, the charge transport within the light-emitting layer is appropriately adjusted to suppress deterioration of the light-emitting material, resulting in a longer drive life. I think I lost.

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 a compound represented by the formula (260) described later is used as the charge transport material. It is preferable to contain it as. It is preferable to include such a compound as an additional host material from the viewpoint of adjusting the charge balance in the light-emitting layer and from the viewpoint of luminous efficiency.

The charge transport material used as the host material of the light-emitting layer is preferably a polymer material from the viewpoint of excellent flexibility. A light-emitting layer formed using a material with excellent flexibility is preferable as a light-emitting layer of an organic electroluminescent device formed on a flexible substrate. When the charge transport material used as the host material included in the light-emitting layer is a polymer 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, and even 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 preferably low molecule from the viewpoints of ease of synthesis and purification, ease of designing electron transport performance and hole transport performance, and ease of viscosity adjustment when dissolved in a solvent. When the charge transport material used as the host material included 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, particularly preferably 3,000 or less, and most preferably 2,000 or less. , is usually 600 or more, preferably 800 or more, more preferably 1,100 or more, and when the layer formed in contact with the light-emitting layer is formed by a wet film forming method, it is preferably 1,000 or more, and more preferably 1,100 or more. , especially preferably 1,200 or more.

<Compound represented by formula (240)>

[Formula 60]

(In equation (240),

Ar ⁶¹¹ and Ar ⁶¹² each independently represent a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent,

R ⁶¹¹ and R ⁶¹² are each independently a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent,

G represents a single bond or a divalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent,

n ⁶¹¹ and n ⁶¹² are each independently integers from 0 to 4.)

＜Ar ⁶¹¹ , Ar ⁶¹² ＞

Ar ⁶¹¹ and Ar ⁶¹² each independently represent a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent.

The carbon number of the aromatic hydrocarbon group is preferably 6 to 50, more preferably 6 to 30, and still more preferably 6 to 18. The aromatic hydrocarbon group specifically includes a benzene ring, naphthalene ring, anthracene ring, tetraphenylene ring, phenanthrene ring, chrysene ring, pyrene ring, benzoanthracene ring, or perylene ring, and the number of carbon atoms is usually 6 or more. , usually 30 or less, preferably 18 or less, more preferably 14 or less, a monovalent group with an aromatic hydrocarbon structure, or a monovalent group with a structure in which a plurality of structures selected from these structures are bonded in a chain or branched form. there is. When multiple aromatic hydrocarbon rings are connected, a structure in which 2 to 8 rings are connected is usually used, and a structure in which 2 to 5 rings are connected is preferable. When multiple aromatic hydrocarbon rings are connected, the same structure may be connected or different structures may be connected.

Ar ⁶¹¹ and Ar ⁶¹² are preferably each independently,

phenyl group,

A monovalent group in which multiple benzene rings are combined in a chain or branched form,

A monovalent group in which one or more benzene rings and at least one naphthalene ring are bonded in a chain or branched form,

A monovalent group in which one or more benzene rings and at least one phenanthrene ring are bonded in a chain or branched form, or,

It is a monovalent group in which one or more benzene rings and at least one tetraphenylene ring are bonded in a chain or branched manner, more preferably, it is a monovalent group in which a plurality of benzene rings are bonded in a chain or branched form, which In this case, the order of combination does not matter.

It is especially preferable that Ar ⁶¹¹ and Ar ⁶¹² are each independently a monovalent group in which a plurality of benzene rings, which may have a substituent, are bonded in a chain or branched form, and each independently, a plurality of benzene rings in a chain or branched form are formed. It is most preferable that it is a bonded monovalent group.

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

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

[Formula 61]

In each of the above formulas (72-1) to (72-7), * represents a bond to an adjacent structure or a hydrogen atom, and at least one of the two * represents a bond position to 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 (72-7).

More preferably, Ar ⁶¹¹ and Ar ⁶¹² each have at least one partial structure selected from formulas (72-1) to (72-3) and (72-7).

Particularly preferably, Ar ⁶¹¹ and Ar ⁶¹² each have at least one partial structure selected from formula (72-1), formula (72-2), and formula (72-7).

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

[Formula 62]

More preferably, the formula (72-2) is the following formula (72-2-3).

[Formula 63]

In addition, from the viewpoint of solubility and durability of the compound, it is preferable to have at least one of Ar ⁶¹¹ and Ar ⁶¹² , which includes a partial structure represented by the formula (72-1) and a partial structure represented by the formula (72-2). structure can be mentioned.

＜R ⁶¹¹ , R ⁶¹² ＞

R ⁶¹¹ and R ⁶¹² each independently represent a halogen atom such as a deuterium atom or a fluorine atom, or a monovalent aromatic hydrocarbon having 6 to 50 carbon atoms which may have a substituent.

Preferably, it is a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent.

The aromatic hydrocarbon group is more preferably a monovalent group with an aromatic hydrocarbon structure having 6 to 30 carbon atoms, further preferably 6 to 18 carbon atoms, and particularly preferably 6 to 10 carbon atoms.

The monovalent aromatic hydrocarbon group is specifically the same as Ar ⁶¹¹ above, and the preferred aromatic hydrocarbon group is the same, and 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 can be specifically selected from the substituent group Z2 described later. A preferable substituent is a preferable substituent of substituent group Z2 described later.

＜n ⁶¹¹ , n ⁶¹² ＞

n ⁶¹¹ and n ⁶¹² are each independently integers from 0 to 4. Preferably it is 0 to 2, and more preferably 0 or 1.

＜Substituent＞

When Ar ⁶¹¹ , Ar ⁶¹² , R ⁶¹¹ , and R ⁶¹² are monovalent aromatic hydrocarbon groups, the substituent they may have is preferably a substituent selected from the following substituent group Z2.

＜Substituent group Z2＞

Substituent group Z2 is 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, an arylthio group. , a group consisting of a silyl group, a siloxy group, a cyano group, an aromatic hydrocarbon group, and an aromatic heterocyclic group. These substituents may have any of linear, branched, and cyclic structures.

More specifically, the substituent group Z2 includes 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. A straight chain, branch, or ring having a carbon number of usually 1 or more, preferably 4 or more, usually 24 or less, preferably 12 or less, more preferably 8 or less, and even more preferably 6 or less. Alkyl group of the form;

For example, an alkoxy group, such as a methoxy group or an ethoxy group, whose carbon number is usually 1 or more, usually 24 or less, and preferably 12 or less;

For example, an aryloxy group or heteroaryloxy group, such as a phenoxy group, naphthoxy group, pyridyloxy group, etc., whose carbon number is usually 4 or more, preferably 5 or more, usually 36 or less, and preferably 24 or less. ;

For example, alkoxycarbonyl groups such as methoxycarbonyl group and ethoxycarbonyl group, where the carbon number is usually 2 or more, usually 24 or less, and preferably 12 or less;

For example, dialkylamino groups such as dimethylamino group and diethylamino group whose carbon number is usually 2 or more, usually 24 or less, and preferably 12 or less;

For example, diarylamino groups such as diphenylamino group and ditolylamino group, which have a carbon number of usually 10 or more, preferably 12 or more, usually 36 or less, and preferably 24 or less;

For example, an arylalkylamino group such as a phenylmethylamino group, where the carbon number is usually 7 or more, usually 36 or less, and preferably 24 or less;

For example, an acyl group such as an acetyl group or benzoyl group, where the carbon number is usually 2 or more, usually 24 or less, and preferably 12 or less;

For example, halogen atoms such as fluorine atom and chlorine atom;

For example, a haloalkyl group such as a trifluoromethyl group, where the carbon number is usually 1 or more, usually 12 or less, and preferably 6 or less;

For example, alkylthio groups such as methylthio groups and ethylthio groups, which have a carbon number of usually 1 or more, usually 24 or less, and preferably 12 or less;

For example, arylthio groups such as phenylthio groups, naphthylthio groups, and pyridylthio groups, where the carbon number is usually 4 or more, preferably 5 or more, usually 36 or less, and preferably 24 or less;

For example, silyl groups such as trimethylsilyl group and triphenylsilyl group whose carbon number is usually 2 or more, preferably 3 or more, usually 36 or less, and preferably 24 or less;

For example, siloxy groups such as trimethylsiloxy group and triphenylsiloxy group, where the carbon number is usually 2 or more, preferably 3 or more, usually 36 or less, and preferably 24 or less;

Cyano group;

For example, aromatic hydrocarbon groups such as phenyl group and naphthyl group whose carbon number is usually 6 or more, usually 36 or less, and preferably 24 or less;

For example, aromatic heterocyclic groups such as thienyl group and pyridyl group, which have a carbon number of usually 3 or more, preferably 4 or more, usually 36 or less, and preferably 24 or less.

Among the above substituent group Z2, an alkyl group, an alkoxy group, a diarylamino group, an aromatic hydrocarbon group, or an aromatic heterocyclic group is preferable. 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 even more preferably no substituent. From the viewpoint of improving solubility, an alkyl group or an alkoxy group is preferable as the substituent.

In addition, each substituent in the above substituent group Z2 may further have a substituent. Those substituents include the same substituents as the above (substituent group Z2). Each substituent that the substituent group Z2 may have is preferably an alkyl group with 8 or less carbon atoms, an alkoxy group with 8 or less carbon atoms, or a phenyl group, more preferably an alkyl group with 6 or less carbon atoms, an alkoxy group with 6 or less carbon atoms, or It is a phenyl group, and it is more preferable that each substituent of the substituent group Z2 does not have an additional substituent from the viewpoint of charge transport properties.

＜G＞

G represents a single bond or a divalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent.

The carbon number of the aromatic hydrocarbon group of G is preferably 6 to 50, more preferably 6 to 30, and still more preferably 6 to 18. The aromatic hydrocarbon group specifically includes a benzene ring, naphthalene ring, anthracene ring, tetraphenylene ring, phenanthrene ring, chrysene ring, pyrene ring, benzoanthracene ring, or perylene ring, and the number of carbon atoms is usually 6 or more. , usually 30 or less, preferably 18 or less, more preferably 14 or less, a divalent group of an aromatic hydrocarbon structure, or a divalent group of a structure in which a plurality of structures selected from these structures are bonded in a chain or branched form. there is. When multiple aromatic hydrocarbon rings are connected, a structure in which 2 to 8 rings are connected is usually used, and a structure in which 2 to 5 rings are connected is preferable. When multiple aromatic hydrocarbon rings are connected, the same structure may be connected or different structures may be connected.

G is preferably,

single bond,

phenylene group,

A divalent group in which multiple benzene rings are combined in a chain or branched form,

A divalent group in which one or more benzene rings and at least one naphthalene ring are bonded in a chain or branched form,

A divalent group in which one or more benzene rings and at least one phenanthrene ring are bonded in a chain or branched form, or,

It is a divalent group in which one or more benzene rings and at least one tetraphenylene ring are bonded in a chain or branched manner, more preferably, it is a divalent group in which a plurality of benzene rings are bonded in a chain or branched form, which In this case, the order of combination does not matter.

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

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

＜Molecular weight＞

The compound represented by the above formula (240) is a low molecular weight material, and its molecular weight is preferably 3,000 or less, more preferably 2,500 or less, further preferably 2,000 or less, particularly preferably 1,500 or less, and usually 300 or more. It is preferably 350 or more, more preferably 400 or more.

<Specific examples of compound IV represented by the above formula (240)>

Below, preferred specific examples of compound IV represented by the above formula (240) are shown, but the present invention is not limited to these.

[Formula 64]

The composition for forming an emitting layer of the present invention may contain only one type or two or more types of the compound represented by the above formula (240).

[Compound: Compound represented by formula (260)]

The composition for forming a light-emitting layer of the present invention in one embodiment contains a compound represented by the following formula (260).

[Formula 65]

(In formula (260), Ar ²¹ to Ar ³⁵ each independently represent a hydrogen atom, a phenyl group which may have a substituent, or a monovalent group of 2 to 10 phenyl groups which may have a substituent, unbranched or branchedly connected. )

In formula (260), when Ar ²¹ to Ar ³⁵ are a phenyl group that may have a substituent or a monovalent group of 2 to 10 phenyl groups that may have a substituent, which are unbranched or linked by branching, the phenyl group may have The substituent is preferably an alkyl group.

＜Alkyl group as a substituent＞

The alkyl group as a substituent is a straight-chain, branched, or cyclic alkyl group usually having 1 or more and 12 or less carbon atoms, preferably 8 or less, more preferably 6 or less, and more preferably 4 or less. 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, cyclohexyl group, 2-ethyl. A hexyl group can be mentioned.

In the above formula (260), Ar ²¹ , Ar ²⁵ , Ar ²⁶ , Ar ³⁰ , Ar ³¹ and Ar ³⁵ are preferably hydrogen atoms. In addition, at least one of Ar ²² to Ar ²⁴ is a phenyl group that may have the above substituents or a monovalent group containing 2 to 10 phenyl groups that may have the above substituents, unbranched or branched, and/or Ar ²² At least one of ~ Ar ²⁴ and at least one of Ar ²⁷ ~ Ar ²⁹ are a phenyl group which may have the above substituents or a monovalent group of 2 to 10 phenyl groups which may have the above substituents, unbranched or branchedly linked. desirable.

More preferably, Ar ²² to Ar ²⁴ , Ar ²⁷ to Ar ²⁹ , and Ar ³² to Ar ³⁴ are hydrogen atoms, phenyl groups, and any of the structures selected from the following formulas (261-1) to (261-9): will be.

These structures may have the above substituent or, for example, may be substituted with an alkyl group as the above substituent. From the viewpoint of improving solubility, it is preferable that it is substituted with an alkyl group. From the viewpoint of charge transport properties and durability when driving the device, it is preferable not to have a substituent.

[Formula 66]

It is thought that when the compound represented by the above formula (260) contains such a structure, the charge transport property in the light-emitting layer can be appropriately adjusted, and the luminous efficiency is increased. In addition, it is believed that by including such a structure, solubility and durability during device operation are excellent.

＜Molecular weight＞

The compound represented by the formula (260) is a low molecular weight material, and its molecular weight is preferably 3,000 or less, more preferably 2,500 or less, particularly preferably 2,000 or less, most preferably 1,500 or less, and usually 300 or more. It is 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, but examples include the following compounds.

[Formula 67]

[Formula 68]

The composition for forming an emitting layer of the present invention may contain only one type or two or more types of the compound represented by the above formula (260).

[Other ingredients]

The composition for an organic electroluminescent device of the present invention may contain various other solvents as needed in addition to the solvent and light emitting material described above. Examples of other such solvents include amides such as N,N-dimethylformamide and N,N-dimethylacetamide, and dimethyl sulfoxide.

Additionally, the composition for an organic electroluminescent device of the present invention may contain various additives such as a leveling agent and an antifoaming agent.

In addition, when two or more layers are laminated by a wet film forming method, in order to prevent these layers from mixing together, a photocurable resin or a thermosetting resin may be contained for the purpose of curing and insolubilizing the film after film formation. .

[Mixing ratio]

Solid content concentration in the composition for organic electroluminescent devices [concentration of all solids including the aromatic hydrocarbon compound of the present invention, the light emitting material, host materials other than the aromatic hydrocarbon compound of the present invention, and components that can be added as needed (leveling agent, etc.) ] is usually 0.01 mass% or more, preferably 0.05 mass% or more, more preferably 0.1 mass% or more, further preferably 0.5 mass% or more, most preferably 1 mass% or more, and usually 80 mass% or less. , preferably 50 mass% or less, more preferably 40 mass% or less, further preferably 30 mass% or less, and most preferably 20 mass% or less. If the solid content concentration is within this range, it is preferable because it is easy to form a thin film of the desired film thickness with a uniform thickness.

The preferred mixing ratio of the aromatic hydrocarbon compound of the present invention with respect to all host materials included in the light emitting layer is as follows. In addition, 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 device of the present invention, the mass ratio of the compound of the present invention to the mass of 100 of the entire host material, that is, the mass ratio of the compound of the present invention to the mass of 100 of the entire host material in the light emitting layer is 5 or more, Preferably it is 10 or more, more preferably 15 or more, more preferably 20 or more, especially preferably 30 or more, and 99 or less, preferably 95 or less, more preferably 90 or less, and more preferably 80. or less, particularly preferably 70 or less.

In addition, in the composition for an organic electroluminescent device of the present invention, the molar ratio of the compound of the present invention to the entire host material, that is, the molar ratio of the compound of the present invention to the entire host material in the light emitting layer is 5 mol% or more, preferably. 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, further Preferably it is 70 mol% or less, and especially preferably is 60 mol% or less.

In addition, in the composition for an organic electroluminescent device of the present invention, the mass ratio of the light-emitting material to the mass of 100 of all host materials, that is, the mass ratio of the light-emitting material to the mass of 100 of all host materials in the light-emitting layer is preferably 0.1 or more. Preferably it is 0.5 or more, more preferably 1 or more, most preferably 2 or more, 100 or less, preferably 60 or less, more preferably 50 or less, and most preferably 40 or less. If this ratio falls below the lower limit or exceeds the upper limit, there is a risk that the luminous efficiency will significantly decrease.

[Method for preparing composition]

The composition for an organic electroluminescent device of the present invention is prepared by dissolving in an appropriate solvent a solute consisting of the aromatic compound of the present invention, the above-described light-emitting material, and various additives such as a leveling agent or anti-foaming agent that can be added as needed. .

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

[Properties of the composition, physical properties, etc.]

(moisture concentration)

When an organic electroluminescent device is manufactured by forming a layer by a wet film forming method using the composition of the present invention, if moisture is present in the composition, moisture is mixed into the formed film and the uniformity of the film is damaged, so the composition of the present invention It is desirable that the moisture content in the water be as small as possible. Additionally, in general, organic electroluminescent devices use many materials that are significantly deteriorated by moisture, such as cathodes. Therefore, if moisture is present in the composition, the moisture will remain in the film after drying and may deteriorate the properties of the device. Considering the possibility, it is not desirable.

Specifically, the moisture content 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 moisture concentration in the composition, the method described in the Japanese Industrial Standard "Method for measuring moisture in chemical products" (JIS K0068:2001) is preferable, for example, analysis by Karl Fischer reagent method (JIS K0211-1348), etc. can do.

(uniformity)

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

(Properties)

If the viscosity of the composition of the present invention is extremely low, for example, drawing unevenness due to excessive liquid film flow in the film forming process, nozzle discharge defects in inkjet film forming, etc. are likely to occur. When the viscosity of the composition of the present invention is extremely high, nozzle clogging during inkjet film formation is likely to occur.

For this reason, 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 it is 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, problems such as lowered wettability of the film forming liquid to the substrate, poor leveling properties of the liquid film, and easy occurrence of disorder of the film forming surface during drying occur. There are cases.

For this reason, 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.

Additionally, 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.

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

[Tabernacle method]

The film forming method using the composition of the present invention is a wet film forming method. The wet film forming method is a method of applying a composition to form a liquid film, drying it to remove the organic solvent, and forming a film. When the composition of the present invention is a composition for an organic electroluminescent device, the organic layer of the organic electroluminescent device can be formed by a thin film formation method including the step of forming such a composition into a film by a wet film formation method. Additionally, when the composition of the present invention contains a light-emitting material, a light-emitting layer can be formed by this method. Application methods include, for example, spin coat method, dip coat method, die coat method, bar coat method, blade coat method, roll coat method, spray coat method, capillary coat method, inkjet method, nozzle printing method, This refers to a method of forming a film by employing a wet film forming method such as screen printing, gravure printing, or flexo printing, and drying the coating film. Among these film forming methods, spin coating method, spray coating method, inkjet method, nozzle printing method, etc. are preferable. When manufacturing an organic EL display device equipped with an organic electroluminescent element, the inkjet method or nozzle printing method is preferable, and the inkjet method is particularly preferable.

The drying method is not particularly limited, but natural drying, reduced pressure drying, heat drying, or reduced pressure drying with heating can be used as appropriate. Heat drying may be performed to further remove residual organic solvent after natural drying or reduced pressure drying.

For reduced-pressure drying, it is preferable to reduce the pressure to below the vapor pressure of the organic solvent contained in the composition for forming a light-emitting layer.

In the case of 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 temperature is usually preferably 80°C or higher and 100°C or higher, more preferably 110°C or higher, more preferably 200°C or lower, and even more preferably 150°C or lower.

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

[Electron transport layer]

As will be described later, in an 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 with the composition of the present invention, and to form an electron transport layer in contact with 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 present invention contains at least an electron transport layer material and a solvent. As a solvent for the composition for forming an electron transport layer, an alcohol-based solvent is preferable. As the electron transport layer material of the composition for forming the electron transport layer, an electron transport material soluble in the alcohol-based solvent is preferable.

As the alcohol-based solvent, an aliphatic alcohol having 3 or more carbon atoms is preferable. Aliphatic alcohols with 6 or more carbon atoms are more preferable because they easily dissolve electron transport materials, have a moderately high boiling point, and are easy to 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-pentanol, 4-octanol, 3,3-diethoxy-1-propanol, 3-(methylamino)-1-propanol, etc. You may mix two or more types of these alcohols as a solvent.

[Method of forming electron transport layer by wet film formation]

The method of forming the electron transport layer by wet film formation is preferably using the method described in the wet film formation described in the film formation method of the light emitting layer above.

[Organic electroluminescent device]

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

[Board]

The substrate 1 serves as a support for the organic electroluminescent element, and usually a quartz or glass plate, a metal plate or metal foil, a plastic film or sheet, etc. are used. Among these, glass plates and plates of transparent synthetic resins such as polyester, polymethacrylate, polycarbonate, and polysulfone are preferable. The substrate is preferably made of a material with high gas barrier properties because deterioration of the organic electroluminescent element due to external air is unlikely to occur. For this reason, especially when using a material with low gas barrier properties, such as a synthetic resin substrate, it is desirable to increase the gas barrier properties by forming a dense silicon oxide film on at least one side of the substrate.

[anode]

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

Anode (2) Silver, typically metals such as aluminum, gold, silver, nickel, palladium, and platinum; Metal oxides such as oxides of indium and/or tin; Halogenated metals such as copper iodide; It is composed of carbon black and conductive polymers such as poly(3-methylthiophene), polypyrrole, and polyaniline.

The formation of the anode 2 is often performed by a dry method such as sputtering or vacuum deposition. In addition, when forming an anode 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., they are dispersed in an appropriate binder resin solution and applied on the substrate. It can also be formed. Additionally, in the case of conductive polymers, a thin film can be formed directly on the substrate by electrolytic polymerization, or the anode can be formed by applying the conductive polymer on the substrate (Appl. Phys. Lett., Vol. 60, Page 2711, 1992 year).

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

The thickness of the anode 2 may be determined depending on the required transparency, material, etc. In particular, when high transparency is required, a thickness with a visible light transmittance of 60% or more is preferable, and a thickness with a visible light transmittance of 80% or more is more preferable. The thickness of the anode 2 is usually 5 nm or more, preferably 10 nm or more, and is 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 any thickness depending on the required strength, etc. In this case, the anode 2 may have the same thickness as the substrate.

When forming another layer on the surface of the anode 2, by performing treatment with ultraviolet rays/ozone, oxygen plasma, argon plasma, etc. before forming the film, impurities on the anode 2 are removed and its ionization potential is adjusted. It is desirable to improve hole injection properties.

[Hole injection layer]

The layer responsible for transporting holes from the anode 2 side to the light emitting layer 5 side is usually called a hole injection and transport layer or a hole transport layer. When there are two or more layers responsible for transporting 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 because it enhances 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 film 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 forming method. In terms of excellent film forming properties, it is preferable to form by a wet film forming method.

Below, a general method of forming a hole injection layer will be described. However, in the organic electroluminescent device of the present invention, the hole injection layer is preferably formed by a wet film forming method using the composition for an organic electroluminescent device described above. do.

The composition for forming a hole injection layer usually contains a hole transport compound for the hole injection layer that becomes the hole injection layer (3). In addition, the composition for forming a hole injection layer usually further contains a solvent in the case of a wet film forming method. The composition for forming a hole injection layer preferably has high hole transport properties and is capable of efficiently transporting injected holes. For this reason, it is desirable that the hole mobility is high and that impurities that become traps are unlikely to be generated during manufacturing or use. Additionally, it is desirable to have excellent stability, small ionization potential, and high transparency to visible light. In particular, when the hole injection layer is in contact with the light-emitting layer, it is preferable not to quench the light emission from the light-emitting layer or to form an exciplex with the light-emitting layer and not reduce the light emission efficiency.

As the hole transport compound for the hole injection layer, a compound having an ionization potential of 4.5 eV to 6.0 eV is preferable from the viewpoint of the 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, compounds in which a tertiary amine is linked to a fluorene group, Hydrazone-based compounds, silazane-based compounds, quinacridone-based compounds, etc. can be mentioned.

Among the above-mentioned exemplary compounds, aromatic amine compounds are preferable, and aromatic tertiary amine compounds are particularly preferable from the viewpoint of amorphousness and visible light transparency. Here, the aromatic tertiary amine compound refers to a compound having an aromatic tertiary amine structure, and also includes a compound having a group derived from an aromatic tertiary amine.

The type of aromatic tertiary amine compound is not particularly limited, but because it is easy to obtain uniform light emission due to the surface smoothing effect, polymer compounds with a weight average molecular weight of 1,000 or more and 1,000,000 or less (polymerized compounds with consecutive repeating units) ) is desirable to use.

When forming the hole injection layer 3 by a wet film formation method, the material to be the hole injection layer is usually mixed with a solvent capable of dissolving it (solvent for the hole injection layer) to form a composition for film formation (composition for forming the hole injection layer) ) is prepared. Then, this composition for forming a hole injection layer is applied on the layer corresponding to the lower layer of the hole injection layer (usually the anode), formed into a film, and dried to form the hole injection layer 3.

The concentration of the hole-transporting compound in the composition for forming a hole injection layer is arbitrary as long as it does not significantly impair the effect of the present invention, but in terms of film thickness uniformity, it is preferable that it is lower, and on the other hand, in the hole injection layer Since defects are less likely to occur, a higher value is preferable. Specifically, it is preferably 0.01 mass% or more, more preferably 0.1 mass% or more, especially preferably 0.5 mass% or more, and on the other hand, 70 mass% or less is preferable, and 60 mass% or less is more preferable, It is especially preferable that it is 50% by mass or less.

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

Ether-based solvents include, for example, aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol-1-monomethyl ether acetate (PGMEA), and 1,2-dimethoxybenzene, 1,3- Aromatic ethers such as dimethoxybenzene, anisole, phenetol, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, and 2,4-dimethylanisole. You can.

Examples of the ester-based solvent 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, and cyclohexyl. Benzene, methylnaphthalene, etc. can be mentioned.

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

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

Formation of the hole injection layer 3 by a wet film formation method usually involves preparing a composition for forming a hole injection layer, and then applying this to a layer corresponding to the lower layer of the hole injection layer 3 (usually, the anode 2). ) is carried out by applying a film onto the surface and drying it.

After the hole injection layer 3 is formed, the coating film is usually dried by heating or reduced-pressure drying.

When forming the hole injection layer 3 by a vacuum deposition method, usually one or two or more types of constituent materials of the hole injection layer 3 are placed in a crucible installed in a vacuum container (two or more types of materials are used) In this case, each is usually placed in a different crucible), and the inside of the vacuum container is evacuated to about 10 ^-4 Pa with a vacuum pump. After that, the crucible is heated (when two or more types of materials are used, each crucible is usually heated), and the materials in the crucible are evaporated while controlling the evaporation amount (when two or more types of materials are used, each crucible is usually heated). evaporate while independently controlling the evaporation amount), and form a hole injection layer on the anode on the substrate placed facing the crucible. Additionally, when using two or more types of materials, their mixture can be placed in a crucible, heated, and evaporated to form a hole injection layer.

The degree of vacuum during deposition is not limited as long as it does not significantly impair the effect of the present invention, but is usually 0.1 × 10 ^-6 Torr (0.13 × 10 ^-4 Pa) or more, 9.0 × 10 ^-6 Torr (12.0 × 10 ^-4 Pa) or less. The deposition rate is not limited as long as it does not significantly impair the effect of the present invention, but is usually 0.1 Å/sec or more and 5.0 Å/sec or less. The film formation temperature during vapor deposition is not limited as long as it does not significantly impair the effect of the present invention, but is preferably performed at 10°C or higher and 50°C or lower.

In addition, the hole injection layer 3 may be crosslinked similarly to 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. Although the hole transport layer 4 is not an essential layer in the organic electroluminescent device of the present invention, 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. do. 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. Moreover, when the above-mentioned hole injection layer 3 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.

The material forming the hole transport layer 4 is preferably a material that has high hole transport properties and can efficiently transport injected holes. Therefore, it is desirable that the ionization potential is small, the transparency to visible light is high, the hole mobility is high, the stability is excellent, and impurities that become traps are unlikely to be generated during production or use. In addition, in many cases, since the hole transport layer 4 is in contact with the light-emitting layer 5, it quenches light emission from the light-emitting layer 5 or forms an exciplex between the light-emitting layer 5 and reduces efficiency. It is advisable not to do this.

The material of the hole transport layer 4 may be any material that has conventionally been used as a constituent material of the hole transport layer, and examples include those exemplified as the hole transport compound used in the hole injection layer 3 described above. there is. In addition, arylamine derivatives, fluorene derivatives, spiro derivatives, carbazole derivatives, pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, phthalocyanine derivatives, porphyrin derivatives, silol derivatives, and oligothiamine derivatives. Examples include ophene derivatives, condensed polycyclic aromatic derivatives, and metal complexes.

Also, for example, polyvinylcarbazole derivatives, polyarylamine derivatives, polyvinyltriphenylamine derivatives, polyfluorene derivatives, polyarylene derivatives, polyarylene ether sulfone derivatives containing tetraphenylbenzidine, polyarylene vinyl Examples include lene derivatives, polysiloxane derivatives, polythiophene derivatives, and poly(p-phenylenevinylene) derivatives. These may be any of alternating copolymers, random polymers, block polymers, or graft copolymers. Additionally, it may be a polymer having a branch in the main chain and three or more terminal portions, or a so-called dendrimer.

Among them, polyarylamine derivatives and polyarylene derivatives are preferable.

As the polyarylamine derivative, a polymer containing a repeating unit represented by the following formula (II) is preferable. 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 of the repeating units.

[Formula 69]

(In formula (II), Ar ^a and Ar ^b each independently represent an aromatic hydrocarbon group that may have a substituent or an aromatic heterocyclic group that may have a substituent.)

Examples of polyarylene derivatives include polymers having an arylene group in the repeating unit, such as an aromatic hydrocarbon group that may have a substituent or an aromatic heterocyclic group that may have a substituent.

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

[Formula 70]

(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, an alkoxyphenyl group, or an alkyl group. Represents a carbonyl group, an alkoxycarbonyl group, or a carboxyl group. t and s each independently represent an integer from 0 to 3. When t or s is 2 or more, a plurality of R ^a or R ^b contained in one molecule may be the same. They may be different, and adjacent R ^a or R ^b may form a ring.)

[Formula 71]

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

Specific examples of It is a carbon atom that may have a substituent or a group formed by combining them.

In addition, the polyarylene derivative preferably has a repeating unit represented by the formula (III-3) below, in addition to the repeating unit represented by the formula (III-1) and/or formula (III-2). do.

[Formula 72]

(In formula (III-3), Ar ^c to Ar ⁱ each independently represent an aromatic hydrocarbon group that may have a substituent or an aromatic heterocyclic group that may have a substituent. v and w each independently represent 0 or It represents 1.)

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

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

The composition for forming a hole transport layer contains a solvent in addition to the hole transport compound described above. The solvent used is the same as that used in the composition for forming the hole injection layer. In addition, the film forming conditions, heating and drying conditions, etc. are the same as those for forming the hole injection layer 3.

In the case of forming a hole transport layer by vacuum deposition, the film formation conditions, etc. are the same as in the case of forming the hole injection layer 3.

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

Additionally, the hole transport layer 4 may be a layer formed by crosslinking a crosslinkable compound. A crosslinkable compound is a compound having a crosslinkable group, and forms a network-like polymer compound by crosslinking.

Examples of this crosslinkable group include groups derived from cyclic ethers such as oxetane and epoxy; Groups derived from unsaturated double bonds such as vinyl group, trifluorovinyl group, styryl group, acrylic group, methacryloyl group, and cinnamoyl group; Groups derived from benzocyclobutene, etc. can be mentioned.

The crosslinkable compound may be any of monomers, oligomers, and polymers. The crosslinkable compound may have only one type or two or more types in any combination and ratio.

As the crosslinkable compound, it is preferable to use a hole transporting compound having a crosslinkable group. Examples of the hole-transporting compound include those exemplified above, and examples of the cross-linking compound include those in which the cross-linking group is bonded to the main chain or side chain of these hole-transporting compounds. In particular, it is preferable that the crosslinkable group is bonded to the main chain through 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, and the crosslinkable group in the formula (II) or formulas (III-1) to (III-3) is directly or a linking group. It is preferable that it is a polymer having repeating units bonded through.

To form the hole transport layer 4 by crosslinking a crosslinkable compound, a composition for forming a hole transport layer is usually prepared by dissolving or dispersing the crosslinkable compound in a solvent, and then forming a film by wet film formation to crosslink it.

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

[Luminous layer]

The light-emitting layer 5 is a layer that is excited by recombination of holes injected from the anode 2 and electrons injected from the cathode 7 to emit light 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. When there is a hole injection layer on the anode, the light-emitting layer is formed between the hole injection layer and the cathode, and forms a hole injection layer on the anode. When there is a transport layer, it is formed between the hole transport layer and the cathode.

As described above, the organic electroluminescent element in the present invention preferably contains the aromatic compound and the light-emitting material of the present invention as a light-emitting layer.

The film thickness of the light-emitting layer 5 is arbitrary as long as it does not significantly impair the effect of the present invention, but a thicker film is preferable in that defects are less likely to occur in the film, and a thinner film allows for a lower driving voltage. It is preferable because it is easy. For this reason, it is preferable that it is 3 nm or more, and it is more preferable that it is 5 nm or more, and on the other hand, it is generally preferable that it is 200 nm or less, and it is more preferable that it is 100 nm or less.

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

[Hole blocking layer]

A hole blocking layer may be formed between the light emitting layer 5 and the electron injection layer 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 on the cathode (7) side of the light emitting layer (5).

This hole blocking layer serves to prevent holes moving from the anode 2 from reaching the cathode 7 and to efficiently transport 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 a high triplet excitation level (T ₁ ). I can hear it.

Materials for the hole blocking layer that satisfy these conditions include, for example, bis(2-methyl-8-quinolinolato)(phenolato)aluminum and bis(2-methyl-8-quinolinolato). Mixed ligand complexes such as (triphenylsilanolato)aluminum, bis(2-methyl-8-quinolato)aluminum-μ-oxo-bis-(2-methyl-8-quinolilato)aluminum 2-nuclear metal complex metal complexes such as styryl compounds such as distyryl biphenyl derivatives (Japanese Patent Application Laid-Open No. 11-242996), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl) -Triazole derivatives such as 1,2,4-triazole (Japanese Patent Application Publication No. 7-41759), phenanthroline derivatives such as vasocuproin (Japanese Patent Application Publication No. 10-79297), etc. You can. Additionally, compounds having at least one pyridine ring substituted at the 2, 4, and 6 positions described in International Publication No. 2005/022962 are 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 wet film forming method, vapor deposition method, or other methods.

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

[Electron transport layer]

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

Specific examples of the electron transporting compound used in the electron transport layer include metal complexes such as aluminum complexes of 8-hydroxyquinoline (Japanese Patent Application Laid-Open No. 59-194393), 10-hydroxybenzo[h] ]Quinoline metal complex, oxadiazole derivative, distyrylbiphenyl derivative, silol derivative, 3-hydroxyflavone metal complex, 5-hydroxyflavone metal complex, benzoxazole metal complex, benzothiazole metal complex, trisbenzimi Dazolylbenzene (US Patent No. 5645948 specification), quinoxaline compound (Japanese Patent Application Laid-Open No. 6-207169), phenanthroline derivative (Japanese Patent Application Laid-Open No. 5-331459), 2-tert-butyl-9 , 10-N, N'-dicyanoanthraquinone diimine, n-type hydrogenated amorphous silicon carbide, n-type zinc sulfide, n-type zinc selenide, etc.

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 by laminating it on the hole blocking layer by a wet film forming method or a vacuum deposition method in the same manner as above. Typically, a vacuum deposition method is used.

In the present invention, as described above, an electron transport layer can be formed on the light-emitting layer containing the aromatic compound of the present invention by a wet film forming method.

[Electron injection layer]

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

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

Additionally, organic electron transport materials such as nitrogen-containing heterocyclic compounds such as vasophenanthroline and metal complexes such as aluminum complexes of 8-hydroxyquinoline are doped with alkali metals such as sodium, potassium, cesium, lithium, and rubidium. This (described in Japanese Patent Application Laid-Open No. 10-270171, Japanese Patent Application Publication No. 2002-100478, Japanese Patent Application Publication No. 2002-100482, etc.) is because electron injection and transport properties are improved, making it possible to achieve both excellent film quality. desirable.

The film thickness of the electron injection layer is usually 5 nm or more, preferably 10 nm or more, and is 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 electron transport layer 6 thereon by a wet film forming method or a vacuum evaporation method.

The details in the case of the wet film forming method are the same as in the case of the above-mentioned light emitting layer.

In some cases, the hole blocking layer, the electron transport layer, and the electron injection layer are formed into one layer by manipulating the electron transport material and the lithium complex co-dope.

[cathode]

The cathode 7 serves to inject electrons into a layer (electron injection layer or light emitting layer, etc.) on the light emitting layer 5 side.

As the material for the cathode 7, it is possible to use the material used for the anode 2, but in order to efficiently inject electrons, it is preferable to use a metal with a low work function, for example For example, metals such as tin, magnesium, indium, calcium, aluminum, and silver or alloys thereof are used. Specific examples include alloy electrodes with low work functions, such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy.

In terms of stability of the organic electroluminescent device, it is desirable to protect the cathode made of a metal with a low work function by laminating a metal layer with a high work function and stable to the atmosphere on the cathode. Examples of metals to be laminated include 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 floors]

The organic electroluminescent device of the present invention may further have other layers as long as the effect of the present invention is not significantly impaired. In short, between the anode and the cathode, you may have any of the other layers described above.

[Other element configuration]

The organic electroluminescent device of the present invention has a structure opposite to the above description, that is, for example, a cathode, an electron injection layer, an electron transport layer, a hole blocking layer, a light emitting layer, a hole transport layer, a hole injection layer, It is also possible to stack in the order of the anodes.

When applying the organic electroluminescent device of the present invention to an organic electroluminescent device, it may be used as a single organic electroluminescent device, or may be used as a configuration in which a plurality of organic electroluminescent devices are arranged in an array, and an anode may be used as an organic electroluminescent device. It may be used in a configuration where the and cathodes are arranged in an X-Y matrix.

[Method for manufacturing 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 may 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 manufacturing an organic electroluminescent device of the present invention may 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 may be, for example, a light-emitting layer.

In another aspect of the method for manufacturing an organic electroluminescent device of the present invention, the organic layer includes a light-emitting layer and an electron transport layer, and the light-emitting layer is formed by a wet film forming method using the composition for an organic electroluminescent device described above; , the process of forming the electron transport layer by a wet film forming method using a composition for an electron transport layer containing an electron transport material and a solvent may be included in this order. The solvent contained in the composition for the electron transport layer may be an alcohol-based solvent. Additionally, the electron transport layer formed by the wet film forming method can be formed to be laminated directly on the light emitting layer formed by the wet film forming method.

＜Organic EL display device＞

The organic EL display device (organic electroluminescent element display or display device) of the present invention includes the organic electroluminescent element of the present invention. There are no particular restrictions on the form or structure of the organic EL display device of the present invention, and it can be assembled by conventional methods using the organic electroluminescent device of the present invention.

For example, the organic EL display device of the present invention can be formed by the method described in “Organic EL Display” (Ahm Corporation, published on August 20, 2004, by Shizuo Tokito, Chihaya Adachi, and Hideyuki Murata). .

＜Organic EL lighting＞

The organic EL lighting (organic electroluminescent element lighting or lighting device) of the present invention includes the organic electroluminescent element of the present invention. There are no particular restrictions on the form or structure of the organic EL lighting of the present invention, and it can be assembled by conventional methods using the organic electroluminescent device of the present invention.

Example

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In addition, the values of various conditions and evaluation results in the examples below have meaning as preferable upper or lower limits in the embodiments of the present invention, and the preferable ranges are the values of the upper or lower limits described above and the values below. It may be a range defined by the values of examples or a combination of values between examples.

Additionally, in this specification, Ac means an acetyl group, Ph means a phenyl group, dppf means 1,1'-bis(diphenylphosphino)ferrocene, and DMSO means dimethyl sulfoxide. 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)

[Formula 73]

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), and aqueous tripotassium phosphate (2.0 mol/L). , 50 mL) were sequentially added and heated to 50°C. After that, PdCl ₂ (PPh ₃ ) ₂ (0.29 g, 0.41 mmol) was added, and the mixture was stirred at 65°C for 2 hours. After cooling to room temperature, saturated aqueous sodium chloride solution was added, and extraction was performed using toluene. The organic layer was washed with 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 (yield 21.6 g, 95%).

(Synthesis of Compound 1-d)

[Formula 74]

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 the mixture was heated to 50°C. Heated. 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 filtered product was dissolved in toluene, washed with 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 (quantity 20.5 g, yield 87%).

(Synthesis of Compound 1-e)

[Formula 75]

Compound 1-d (20.5 g, 34.4 mmol) and 1-bromo-4-iodobenzene (9.75 g, 34.4 mmol) were subjected to nitrogen bubbling to form an aqueous solution of toluene (100 mL), ethanol (50 mL), and tripotassium phosphate. (2.0 mol/L, 50 mL) was added sequentially and heated to 50°C. After that, PdCl ₂ (PPh ₃ ) ₂ (0.24 g, 0.34 mmol) was added, and the mixture was stirred at 65°C for 2 hours. After cooling to room temperature, saturated aqueous sodium chloride solution was added, and extraction was performed using toluene. The organic layer was washed with 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 (amount 17.8 g, yield 83%).

(Synthesis of Compound 1-f)

[Formula 76]

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 the mixture was heated to 50°C. Heated. 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 filtered product was dissolved in toluene, washed with 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 (amount 16.2 g, yield 90%).

(Synthesis of Compound (H-1))

[Formula 77]

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) and an aqueous solution of tripotassium phosphate (2.0 mol/L, 15 mL) were added in order. 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, saturated aqueous sodium chloride solution and 1 N dilute hydrochloric acid were added, and extraction was performed using dichloromethane. The organic layer was washed with 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) (amount 10.7 g, yield 81%).

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

(Synthesis of Compound 2-b)

[Formula 78]

Under a nitrogen atmosphere, dehydrated THF (100 mL) was added to compound 2-a (19.6 g, 50.9 mmol), and the mixture was cooled to -75°C. After that, n-BuLi (1.58 mol/L, 32.2 mL) was added dropwise, and the mixture was stirred at -75°C for 3 hours. The prepared solution was added dropwise to a dehydrated THF (100 mL) solution of cyanuric chloride (18.8 g, 101.8 mmol) cooled to -100°C. After raising the temperature to room temperature, saturated aqueous sodium chloride solution and 1 N diluted hydrochloric acid were added, and extraction was performed using ethyl acetate. The organic layer was washed with 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 (amount 6.5 g, yield 28%).

(Synthesis of Compound 2-d)

[Formula 79]

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, followed by THF (100 mL) and an aqueous solution of tripotassium phosphate (2.0 mol/L, 13 mL) were added in order. After that, Pd(PPh ₃ ) ₄ (0.12 g, 0.10 mmol) was added, and the mixture was heated and stirred at 55°C for 8 hours. After cooling to room temperature, saturated aqueous sodium chloride solution and 1 N dilute hydrochloric acid were added, and extraction was performed using dichloromethane. The organic layer was washed with 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 (amount 4.9 g, yield 66%).

(Synthesis of Compound 2-g)

[Formula 80]

Under a nitrogen atmosphere, compound 2-e (3.3 g, 9.28 mmol) and compound 2-f (3.6 g, 9.28 mmol) were bubbled with nitrogen and added toluene (40 mL), ethanol (20 mL), and an aqueous solution of tripotassium phosphate ( 2.0 mol/L, 20 mL) were added in order. After that, Pd(PPh ₃ ) ₄ (0.11 g, 0.093 mmol) was added, and the mixture was heated and stirred at 90°C for 4 hours. After cooling to room temperature, saturated aqueous sodium chloride solution was added, and extraction was performed using toluene. The organic layer was washed with 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 (amount 2.6 g, yield 45%).

(Synthesis of Compound 2-h)

[Formula 81]

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 the mixture was heated to 50°C. Heated. 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 filtered product was dissolved in dichloromethane, washed with 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 (amount 0.89 g, yield 32%).

(Synthesis of Compound (H-2))

[Formula 82]

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, followed by THF (30 mL) and an aqueous solution of tripotassium phosphate (2.0 mol/L, 3 mL) were added in order. After that, Pd(PPh ₃ ) ₄ (10 mg, 0.0088 mmol) was added, and the mixture was heated and stirred at 70°C for 5 hours. After cooling to room temperature, saturated aqueous sodium chloride solution and 1 N dilute hydrochloric acid were added, and extraction was performed using dichloromethane. The organic layer was washed with 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) (amount 0.69 g, yield 64%).

<Synthesis example of compound (H-3)>

(Synthesis of Compound 3-b)

[Formula 83]

Under a nitrogen atmosphere, dehydrated THF (100 mL) was added to compound 3-a (22.1 g, 57.3 mmol), and the mixture was cooled to -75°C. After that, n-BuLi (1.58 mol/L, 36.3 mL) was added dropwise, and the mixture was stirred at -75°C for 3 hours. The prepared solution was added dropwise to a dehydrated THF (100 mL) solution of cyanuric chloride (4.75 g, 25.8 mmol) cooled to -100°C. After raising the temperature to room temperature, saturated aqueous sodium chloride solution and 1 N diluted hydrochloric acid were added, and extraction was performed using ethyl acetate. The organic layer was washed with 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 (amount 5.5 g, yield 29%).

(Synthesis of Compound (H-3))

[Formula 84]

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, followed by THF (30 mL) and an aqueous solution of tripotassium phosphate (2.0 mol/L, 10 mL) were added in order. 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, saturated aqueous sodium chloride solution and 1 N dilute hydrochloric acid were added, and extraction was performed using dichloromethane. The organic layer was washed with 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) (quantity 0.72 g, yield 50%).

(Synthesis of comparative compound (C-2))

[Formula 85]

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, followed by THF (15 mL) and an aqueous solution of tripotassium phosphate (2.0 mol/L, 5 mL) were added in order. 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, saturated aqueous sodium chloride solution and 1 N dilute hydrochloric acid were added, and extraction was performed using dichloromethane. The organic layer was washed with 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) (amount 1.0 g, yield 60%).

(Synthesis of comparative compound (C-3))

[Formula 86]

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, followed by THF (20 mL) and an aqueous solution of tripotassium phosphate (2.0 mol/L, 6 mL) were added in order. 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) (amount 1.3 g, yield 68%).

<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 band gap (Eg) calculated from the absorption edge of the absorption spectrum.

The results are shown in Table 1.

In addition, the comparative compounds (C-1) to (C-3) shown below were used.

<Solubility evaluation of compounds (H-1) to (H-3) and comparative compounds (C-1) to (C-3)>

In addition, as an evaluation of the solubility of each compound in cyclohexylbenzene (CHB), prepare a cyclohexylbenzene solution of about 1 to 2 mL (concentration of each compound: 12.0 mass%), and check whether each compound is dissolved in the solution. was evaluated. The results are shown in Table 2. “○” in the column “12.0 mass% CHB solution” in Table 2 means that the compound was dissolved in the solution, and “×” means that the compound was not dissolved in the solution.

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

[Formula 87]

<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 in which the compound to be tested was dissolved in toluene at 1.5% by mass. 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, and 150 µl of test solvent was added dropwise onto the substrate and left to stand for 60 seconds to conduct a solvent resistance test.

After that, the substrate was rotated at 1500 rpm for 30 seconds and then at 4000 rpm for 30 seconds to spin out the dropwise solvent. The substrate was dried on a hot plate at 100°C for 10 minutes. The change in film thickness before and after the solvent resistance test was estimated from the difference in each film thickness.

The film thickness after film formation of each compound and the test solvent used are as follows.

(Compound (H-1))

A 54 nm thick film 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 54 nm thick film 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 54 nm thick film was formed using 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 confirmed.

×: A decrease in film thickness of 5 nm or more was confirmed.

The results of the solvent resistance test are shown in Table 3.

[Example 1]

An organic electroluminescent device was produced by the following method.

An indium/tin oxide (ITO) transparent conductive film deposited to a thickness of 50 nm on a glass substrate (manufactured by Geomatec, sputter-deposited product) was patterned into stripes 2 mm wide using conventional photolithography techniques and hydrochloric acid etching. This formed an anode. The substrate on which the ITO pattern was formed in this way is cleaned in the following order: ultrasonic cleaning with an aqueous surfactant solution, washing with ultrapure water, ultrasonic cleaning with ultrapure water, and washing with ultrapure water, followed by drying with compressed air, and finally ultraviolet ozone cleaning. was carried out.

As a composition for forming a hole injection layer, a composition was prepared by dissolving 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) in ethyl benzoate. did.

[Formula 88]

This solution was spin-coated on the substrate in the air and dried on a hot plate in the air 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 in a nitrogen glove box on the substrate on which the hole injection layer was applied and deposited, 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 film thickness of 40 nm. It was used as a hole transport layer.

[Formula 89]

Subsequently, as the material of the light-emitting layer, the compound (H-1) of the present invention is used at a concentration of 2.3% by weight, the compound (HH-1) having the following structure is 2.3% by weight, and (D-1) is used at a concentration of 1.4% by weight. It was dissolved in cyclohexylbenzene to prepare a composition for forming a light-emitting layer.

[Formula 90]

This solution was spin-coated in a nitrogen glove box on the substrate on which the hole transport layer was applied and deposited, dried on a hot plate in the nitrogen glove box at 120°C for 20 minutes to form a uniform thin film with a film thickness of 40 nm, and a light emitting layer was formed. It was done as follows.

The substrate on which the light-emitting layer was formed was placed in a vacuum evaporation device, and the inside of the device was evacuated until the temperature became 2 x 10 ^-4 Pa or less.

Next, the following structural formula (ET-1) and 8-hydroxyquinolinolatrium were co-deposited at a film thickness ratio of 2:3 on the light emitting layer by vacuum evaporation to form an electron transport layer with a film thickness of 30 nm. .

[Formula 91]

Subsequently, a 2 mm wide striped shadow mask as a mask for cathode deposition was brought into close contact with the substrate so as to be perpendicular to the ITO stripe of the anode, and aluminum was heated with a molybdenum boat to form an aluminum layer with a film thickness of 80 nm. This formed a cathode. As described above, an organic electroluminescent element having a light emitting area portion of 2 mm x 2 mm was obtained.

[Example 2]

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

[Example 3]

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

[Comparative Example 1]

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

[Evaluation of device]

The current efficiency (cd/A) and external quantum efficiency (%) of the organic electroluminescent devices obtained in Examples 1 to 3 and Comparative Example 1 when emitting light at 1,000 cd/m 2 were measured. Additionally, when the device was continuously energized at a current density of 15 mA/cm2, the time (LT95) for the luminance to decrease to 95% of the initial luminance was measured. These measurement results are shown in Table 4. In Table 4, the values of Examples 1 to 3 represent relative values with the value of Comparative Example 1 set to 1. From the results in Table 4, it can be seen that performance is improved in organic electroluminescent devices using the compounds of the present invention.

[Example 4]

An organic electroluminescent device was produced in the same manner as in Example 1, except that the light emitting layer was formed as follows.

As a material for the light-emitting layer, compound (H-1) was dissolved in cyclohexylbenzene at a concentration of 2.7% by weight, the following compound (HH-2) at a concentration of 2.7% by weight, and compound (D-1) at a concentration of 1.6% by weight, and the light-emitting layer was prepared. A composition for forming was prepared.

[Formula 92]

The composition for forming a light-emitting layer is spin-coated on the substrate on which the hole transport layer was formed in a nitrogen glove box, 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 film thickness of 70 nm. It was used as a light emitting layer.

[Example 5]

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

[Example 6]

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

[Comparative Example 2]

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

[Evaluation of device]

The current efficiency (cd/A) and external quantum efficiency (%) of the organic electroluminescent devices obtained in Examples 4 to 6 and Comparative Example 2 when emitting light at 1,000 cd/m 2 were measured. Additionally, when electricity was continuously applied to the device at a current density of 15 mA/cm2, the time (LT97) for the luminance to decrease to 97% of the initial luminance was measured. These measurement results are shown in Table 5. In Table 5, the values of Examples 4 to 6 represent relative values with the value of Comparative Example 2 set to 1. From the results in Table 5, it was found that performance was improved in organic electroluminescent devices using the compounds of the present invention.

Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to these examples. It is clear to those skilled in the art that various changes or modifications can be made within the scope described in the patent claims, and they are naturally understood to fall within the technical scope of the present invention. In addition, each component in the above embodiment may be arbitrarily combined as long as it does not deviate from the spirit of the invention.

In addition, this application is based on a Japanese patent application (Japanese patent application 2021-094594) filed on June 4, 2021, the content of which is incorporated by reference in this application.

The present invention can provide an aromatic compound having excellent heat resistance, excellent solubility, excellent electron transport properties, and excellent durability against alcohol solvents in a thin film. Additionally, the present invention provides 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 thin film formation method, and a manufacturing method of the organic electroluminescent device. can do.

1: substrate
2: anode
3: hole injection layer
4: hole transport layer
5: light emitting layer
6: electron transport layer
7: cathode
8: Organic electroluminescent device

Claims (21)

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

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

(In equation (3), asterisk (*) indicates combination with equation (1),
L ² is a divalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, a divalent heteroaromatic group having 60 carbon atoms or less which may have a substituent, or a divalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, and It is a group in which a plurality of groups selected from divalent heteroaromatic groups having 60 carbon atoms or less which may have a substituent are connected,
Ar ² is a monovalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, a monovalent heteroaromatic group having 60 carbon atoms or less which may have a substituent, or a monovalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent; It is a group in which a plurality of groups selected from monovalent heteroaromatic groups having 60 or less carbon atoms that may have a substituent are connected,
a ² represents an integer from 1 to 5.)

(In equation (4), asterisk (*) indicates combination with equation (1),
L ³ is a divalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, a divalent heteroaromatic group having 60 carbon atoms or less which may have a substituent, or a divalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, and It is a group in which a plurality of groups selected from divalent heteroaromatic groups having 60 carbon atoms or less which may have a substituent are connected,
a ³ represents an integer from 1 to 5.) According to claim 1,
G ¹ is an aromatic compound represented by the following formula (2).

(In equation (2), asterisk (*) indicates combination with equation (1),
L ¹ is a divalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, a divalent heteroaromatic group having 60 carbon atoms or less which may have a substituent, or a divalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, and It is a group in which a plurality of groups selected from divalent heteroaromatic groups having 60 carbon atoms or less, which may have a substituent, are connected,
Ar ¹ is a monovalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent, a monovalent heteroaromatic group having 60 carbon atoms or less which may have a substituent, or a monovalent aromatic hydrocarbon group having 60 carbon atoms or less which may have a substituent; It is a group in which a plurality of groups selected from monovalent heteroaromatic groups having 60 or less carbon atoms which may have a substituent are connected,
a ¹ represents an integer from 0 to 5.) According to claim 2,
An aromatic compound in which L ¹ to L ³ are each independently a phenyl group or a group containing a plurality of phenyl groups linked together. According to claim 2 or 3,
An aromatic compound in which L ¹ to L ³ are each independently a 1,3-phenylene group or a 1,4-phenylene group. The method according to any one of claims 1 to 4,
Aromatic compounds with a molecular weight of 1200 or more. An organic electroluminescent 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 electroluminescent device, wherein the material for the organic electroluminescent device is the aromatic compound according to any one of claims 1 to 5. According to claim 6,
An organic electroluminescent device, wherein the layer containing the material for the organic electroluminescent device is a light emitting layer. A display device comprising the organic electroluminescent element 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 electroluminescent device containing the aromatic compound according to any one of claims 1 to 5 and a solvent. According to claim 10,
Additionally, a composition for an organic electroluminescent device containing a phosphorescent material and a charge transport material. According to claim 11,
A composition for an organic electroluminescent device, wherein the charge transport material is a compound represented by the following formula (240), or a compound represented by the following formula (260).

(In equation (240),
Ar ⁶¹¹ and Ar ⁶¹² each independently represent a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent,
R ⁶¹¹ and R ⁶¹² are each independently a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent,
G represents a single bond or a divalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent,
n ⁶¹¹ and n ⁶¹² are each independently integers from 0 to 4.)

(In formula (260), Ar ²¹ to Ar ³⁵ each independently represent a hydrogen atom, a phenyl group which may have a substituent, or a monovalent group of 2 to 10 phenyl groups which may have a substituent, unbranched or branchedly connected. ) According to claim 12,
A composition for an organic electroluminescent device in which Ar ⁶¹¹ and Ar ⁶¹² in the formula (240) are each independently a monovalent group in which multiple benzene rings, which may have a substituent, are bonded in a chained or branched form. The method of claim 12 or 13,
A composition for an organic electroluminescent device in which R ⁶¹¹ and R ⁶¹² in the formula (240) are each independently a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent. The method according to any one of claims 12 to 14,
A composition for an organic electroluminescent device wherein n ⁶¹¹ and n ⁶¹² in the formula (240) are each independently 0 or 1. According to claim 12,
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, and structures selected from the following formulas (261-1) to (261-9), and these structures are A composition for an organic electroluminescent device which may have the above substituent.
A thin film forming method comprising the step of forming the composition for an organic electroluminescent device according to any one of claims 10 to 16 by a wet film forming method. A method of manufacturing an organic electroluminescent device having an anode and a cathode on a substrate and an organic layer between the anode and the cathode, comprising:
A method for producing an organic electroluminescent device, comprising the step of forming the organic layer by a wet film forming method using the composition for an organic electroluminescent device according to any one of claims 10 to 16. According to claim 18,
A method of manufacturing an organic electroluminescent device, wherein the organic layer is a light-emitting layer. A method of manufacturing an organic electroluminescent device having an anode and a cathode on a substrate and an organic layer between the anode and the cathode, comprising:
The organic layer includes a light-emitting layer and an electron transport layer,
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,
A method for producing an organic electroluminescent device, comprising the step of forming the electron transport layer by a wet film forming method using a composition for an electron transport layer containing an electron transport material and a solvent in this order. According to claim 20,
A method of manufacturing an organic electroluminescent device wherein the solvent contained in the composition for the electron transport layer is an alcohol-based solvent.