CN117480165A

CN117480165A - Compound and organic electroluminescent element

Info

Publication number: CN117480165A
Application number: CN202280039408.2A
Authority: CN
Inventors: 长谷川司; 五郎丸英贵; 冈部一毅; 奈良麻优子
Original assignee: Mitsubishi Chemical Corp
Current assignee: Mitsubishi Chemical Corp
Priority date: 2021-06-04
Filing date: 2022-06-01
Publication date: 2024-01-30

Abstract

A compound represented by the following formula (1-1).(W ₁ 、W ₂ 、W ₃ is-CH or a nitrogen atom. W (W) ₁ 、W ₂ W and W ₃ At least one of which is a nitrogen atom. Xa (Xa) ¹ 、Ya ¹ 、Za ¹ Is a 1, 3-phenylene group which may have a substituent or a 1, 4-phenylene group which may have a substituent. Za (Za) ¹ At least one of which is a 1, 3-phenylene group. Xa (Xa) ² Ya ² Is phenyl which may have a substituent. Za (Za) ² Is an N-carbazolyl group which may have a substituent. f11 is 1 or 2. g11 is an integer of 1 to 5. h11 is an integer of 2 to 5. j11 is an integer of 1 to 6. f11+g11+h11+j11 is 5 or more. R is R ¹¹ Is a hydrogen atom or a substituent. ).

Description

Compound and organic electroluminescent element

Technical Field

The present invention relates to a compound that can be used for an organic electroluminescent element (hereinafter, sometimes referred to as an "organic light emitting diode (organic light emitting diode, OLED)" or an "element"). The present invention also relates to an organic electroluminescent element comprising the compound, a composition comprising the compound and an organic solvent, a method for forming a thin film using the composition, and a method for producing an organic electroluminescent element.

Background

In recent years, as a thin film type electroluminescent element, an organic electroluminescent element using an organic thin film has been developed instead of an organic electroluminescent element using an inorganic material. An organic electroluminescent element (OLED) generally has a hole injection layer, a hole transport layer, an organic light emitting layer, an electron transport layer, and the like between an anode and a cathode. Materials suitable for the respective layers are being developed, and the emission colors are also developed in red, green, and blue, respectively. In addition, research into coated OLEDs, which have higher material utilization efficiency and lower manufacturing costs than conventional vapor deposition types, is being advanced.

In the coating type OLED, a longer lifetime of the element or a driving with lower power consumption is required. Various factors are considered for the reasons that affect the life of the element or the improvement of the power consumption. For example, it is considered that the life of the material constituting the element has a great influence on the heat resistance and durability and crystallinity.

In order to manufacture an organic electroluminescent element by a wet film forming method, all materials used need to be soluble in an organic solvent and used as an ink. If the solubility of the material used is poor, it may be necessary to perform an operation such as heating for a long time, and thus the material may be degraded before use. If the state of the solution is not maintained in a uniform state for a long time, the material is precipitated from the solution, and the film formation by an inkjet device or the like is not performed.

The materials used in the wet film forming method are required to have solubility in two ways, namely, to be rapidly dissolved in an organic solvent and to be kept in a uniform state without precipitation after dissolution.

On the other hand, in order to manufacture an organic electroluminescent element by forming all organic layers by a wet film forming method by coating and forming organic layers in multiple layers, solvent resistance of ink applied thereto after wet film forming is required.

Patent document 1 and patent document 2 report that a triazine compound is used as a charge transport material as a host of a light-emitting layer.

Patent document 1: international publication No. 2007/043357

Patent document 2: international publication No. 2012/096263

In the technical field of organic electroluminescent devices, further improvement in device performance is always demanded.

In patent document 1 and patent document 2, no study has been made on wet film formation by bringing an electron transport layer into contact with a light-emitting layer containing a triazine compound.

The triazine compound having two carbazoles described in patent document 2 has low solvent solubility and poor film forming property by a wet film forming method.

Disclosure of Invention

The present invention provides a compound which has high solvent solubility and can be used for a light-emitting layer of an organic electroluminescent element to obtain an organic electroluminescent element with low voltage, high light-emitting efficiency and long service life. The present invention further provides a compound which is capable of insolubilizing a film containing the compound with respect to a specific solvent in order to enable wet film formation by bringing other layers into contact with the film containing the compound.

Further, the present invention provides an organic electroluminescent element comprising the compound, a composition comprising the compound and an organic solvent, a method for forming a thin film using the composition, and a method for producing an organic electroluminescent element.

The present inventors have found that the above problems can be solved by using a compound having a specific structure.

The gist of the present invention is as follows < 1 > - < 17 >.

< 1 > a compound represented by the following formula (1-1) or the following formula (1-2).

[ chemical 1]

(in the formula (1-1),

w1, W2 and W3 each independently represents-CH or a nitrogen atom, at least one of W1, W2 and W3 being a nitrogen atom,

xa1, ya1 and Za1 each independently represent a1, 3-phenylene group with or without a substituent, or a1, 4-phenylene group with or without a substituent,

at least one of Za1 is 1, 3-phenylene,

xa2 and Ya2 each independently represent a phenyl group having or not having a substituent,

za2 represents an N-carbazolyl group with or without a substituent,

f11 is either 1 or 2,

g11 is an integer of 1 to 5,

h11 is an integer of 2 to 5,

j11 is an integer of 1 to 6,

f11+g11+h11+j11 is 5 or more,

r11 represents a hydrogen atom or a substituent. )

[ chemical 2]

(in the formula (1-2),

At least one of Ya1 and Za1 is a1, 3-phenylene group with or without a substituent,

xa2 represents a phenyl group having or not having a substituent,

ya2 and Za2 each independently represent an N-carbazolyl group having or not having a substituent,

f11 is either 1 or 2,

g11 is an integer of 1 to 5,

h11 is an integer of 2 to 5,

j11 is an integer of 2 to 5,

f11+g11+h11+j11 is 6 or more,

r11 represents a hydrogen atom or a substituent. )

< 2 > the compound of < 1 > wherein at least one of Ya1 in said formula (1-2) is 1, 3-phenylene and at least one of Za1 is 1, 3-phenylene.

< 3 > Compounds of < 1 > or < 2 > wherein at least one of Xa1 in said formula (1-2) is 1, 3-phenylene.

< 4 > an organic electroluminescent element having an anode and a cathode on a substrate, an organic layer between the anode and the cathode,

the organic layer comprises a compound of any one of < 1 > to < 3 >.

The organic electroluminescent element as described in < 5 > to < 4 >, wherein the organic layer comprises a light-emitting layer comprising the compound.

A composition comprising at least a compound as claimed in any one of < 1 > to < 3 > and an organic solvent.

The composition of < 7 > as described in < 6 > further comprising a light-emitting material, and a charge transport material different from the compound represented by the formula (1-1) and the compound represented by the formula (1-2).

The composition of < 8 > to < 7 > wherein the charge transport material different from the compound represented by the formula (1-1) and the compound represented by the formula (1-2) is a compound represented by the following formula (240) and/or a compound represented by the following formula (260).

[ chemical 3]

(in the formula (240),

ar611 and Ar612 each independently represent a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms and having or not having a substituent.

R611 and R612 each independently represent a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms and having or not having a substituent.

G represents a single bond or a divalent aromatic hydrocarbon group having 6 to 50 carbon atoms and optionally having a substituent.

n611 and n612 are each independently an integer of 0 to 4. )

[ chemical 4]

(in the formula (260), ar21 to Ar35 each independently represent a hydrogen atom, a phenyl group having or not having a substituent, or a monovalent group in which 2 to 10 phenyl groups having or not having a substituent are linked in an unbranched or branched manner.)

The composition of < 9 > and < 8 >, wherein Ar611 and Ar612 in the formula (240) are each independently a monovalent group having a plurality of benzene rings bonded in a chain or branched manner, with or without a substituent.

The composition of < 10 > to < 8 > wherein R611 and R612 in the formula (240) are each independently a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms with or without a substituent.

< 11 > the composition of < 8 > wherein n611 and n612 in the formula (240) are each independently 0 or 1.

The composition of < 12 > as set forth in < 8 >, wherein in the formula (260), ar21, ar25, ar26, ar30, ar31 and Ar35 are hydrogen atoms,

ar22 to Ar24, ar27 to Ar29, and Ar32 to Ar34 are each independently a hydrogen atom, a phenyl group having or not having a substituent, or any one selected from the structures of the following formulae (261-1) to (261-9) having or not having a substituent.

[ chemical 5]

A method for forming a thin film, comprising the step of forming a thin film of the composition of any one of < 6 > to < 12 > by a wet film forming method.

< 14 > a method for producing an organic electroluminescent element, wherein the organic electroluminescent element has an anode and a cathode on a substrate, an organic layer is provided between the anode and the cathode,

The method for producing an organic electroluminescent element comprises the step of forming the organic layer by a wet film forming method using the composition of any one of < 6 > to < 12 >.

The method for manufacturing an organic electroluminescent element as described in < 15 > to < 14 >, wherein the organic layer is a light-emitting layer.

< 16 > a method for producing an organic electroluminescent element, wherein the organic electroluminescent element has an anode and a cathode on a substrate, an organic layer is provided between the anode and the cathode, the organic layer comprises a light-emitting layer and an electron transport layer,

the method for manufacturing an organic electroluminescent element comprises the following steps: a step of forming the light-emitting layer by a wet film formation method using the composition as described in any one of < 6 > to < 12 >; and

and forming the electron transport layer by a wet film forming method using a composition for forming an electron transport layer comprising an electron transport material and a solvent.

The method for producing an organic electroluminescent element according to claim 17 < 16, wherein the solvent contained in the composition for forming an electron transport layer is an alcohol-based solvent.

[ Effect of the invention ]

According to the present invention, there can be provided a compound which has high solvent solubility and which can provide an organic electroluminescent element having a low voltage, high luminous efficiency and long life when used in a light-emitting layer of the organic electroluminescent element.

The compound of the present invention is insoluble in a specific solvent and has excellent solvent resistance. Therefore, other layers can be formed by lamination on the film containing the compound of the present invention by a wet film forming method.

According to the present invention, an organic electroluminescent element having the compound, a composition containing the compound and an organic solvent, a thin film forming method, and a method for producing an organic electroluminescent element can be provided.

Drawings

Fig. 1 is a schematic cross-sectional view showing a structural example of an organic electroluminescent element according to the present invention.

[ symbolic description ]

1 substrate

2 anode

3 hole injection layer

4 hole transport layer

5 luminescent layer

6 electron transport layer

7 cathode

8 organic electroluminescent element

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail. The present invention is not limited to the following embodiments, and can be implemented by various modifications within the scope of the gist thereof.

In the present invention, "optionally substituted" means that the compound may have one or more substituents.

[ Compounds of the invention ]

The compound of the present invention is represented by the formula (1-1) or the formula (1-2) disclosed below.

Hereinafter, the compound represented by the formula (1-1) may be referred to as "compound (1-1)", and the compound represented by the formula (1-2) may be referred to as "compound (1-2)".

In addition, the compounds (1-1) and (1-2) are referred to as "compounds of the present invention".

The compounds of the present invention function as charge transport materials. That is, the compound of the present invention has a nitrogen atom-containing hetero six-membered ring, and thus can function as an electron-transporting material.

Therefore, the compound of the present invention is preferably a charge transport compound, that is, a charge transport host material, and is preferably an electron transport host material used as a light emitting layer in an organic electroluminescent element.

The substituents which may be present in the 1, 3-phenylene group, 1, 4-phenylene group, phenyl group and N-carbazolyl group in the formula (1-1) or the formula (1-2) disclosed below may be selected from the following substituent group Q.

Substituent group Q >

Substituent group Q is a group comprising alkyl, alkenyl, alkynyl, alkoxy, aryloxy, heteroaryloxy, alkoxycarbonyl, dialkylamino, diarylamino, arylalkylamino, acyl, halogen atom, haloalkyl, alkylthio, arylthio, silyl, siloxy, cyano, aralkyl, aromatic hydrocarbon group, and aromatic heterocyclic group. These substituents may also comprise any of linear, branched, and cyclic structures.

The substituent group Q may have the following structure.

Examples of the alkyl group include linear, branched, and cyclic alkyl groups having usually 1 or more, preferably 4 or more and usually 24 or less, preferably 12 or less, more preferably 8 or less, and still more preferably 6 or less, and methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-hexyl, cyclohexyl, and dodecyl groups are preferable.

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

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

The alkoxy group is an alkoxy group having usually 1 to 24 carbon atoms, preferably 12 carbon atoms, and more preferably methoxy and ethoxy groups.

Examples of the aryloxy group and the heteroaryloxy group include aryloxy groups having usually 4 or more, preferably 5 or more and usually 36 or less, preferably 24 or less carbon atoms, and preferred examples thereof include phenoxy group, naphthoxy group and pyridyloxy group.

The alkoxycarbonyl group is an alkoxycarbonyl group having usually 2 or more and usually 24 or less, preferably 12 or less, and preferably a methoxycarbonyl group or an ethoxycarbonyl group.

Examples of the dialkylamino group include a dialkylamino group having usually 2 or more and usually 24 or less, preferably 12 or less carbon atoms, and preferable examples thereof include a dimethylamino group and a diethylamino group.

The diarylamino group is a diarylamino group having usually 10 or more, preferably 12 or more and usually 36 or less, preferably 24 or less, and preferably a diphenylamino group or a xylylamino group.

The arylalkylamine group is an arylalkylamine group having usually 7 carbon atoms and usually 36 carbon atoms or less, preferably 24 carbon atoms or less, and preferably a phenylmethylamino group.

Examples of the acyl group include an acyl group having usually 2 carbon atoms and usually 24 or less, preferably 12, and preferably an acetyl group and a benzoyl group.

The halogen atom is preferably a fluorine atom or a chlorine atom.

The haloalkyl group is a haloalkyl group having usually 1 to 12 carbon atoms, preferably 6 carbon atoms, and preferably a trifluoromethyl group.

Examples of the alkylthio group include alkylthio groups having usually 1 to 24 carbon atoms, preferably 12 carbon atoms, and methylthio and ethylthio are preferable.

The arylthio group is usually 4 or more, preferably 5 or more and usually 36 or less, preferably 24 or less, and is preferably phenylthio, naphthylthio or pyridylthio.

The silane group is a silane group having usually 2 or more, preferably 3 or more and usually 36 or less, preferably 24 or less, and preferably a trimethylsilyl group or a triphenylsilyl group.

Examples of the siloxy group include siloxy groups having usually 2 or more, preferably 3 or more and usually 36 or less, preferably 24 or less carbon atoms, and examples thereof include trimethylsiloxy groups and triphenylsiloxy groups.

Cyano is-CN.

Examples of the aralkyl group include aralkyl groups having usually 7 or more, preferably 9 or more, usually 30 or less, preferably 18 or less, more preferably 10 or less carbon atoms such as benzyl group, 2-phenylethyl group, 2-phenylpropyl-2-yl group, 2-phenylbutyl-2-yl group, 3-phenylpentyl-3-yl group, 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 and the like.

The aromatic hydrocarbon group is an aromatic hydrocarbon group having usually 6 or more and usually 36 or less, preferably 24 or less, and preferably a phenyl group or a naphthyl group.

The aromatic heterocyclic group is an aromatic heterocyclic group having usually 3 or more, preferably 4 or more and usually 36 or less, preferably 24 or less, and preferably a thienyl group or a pyridyl group.

The substituent group Q is also preferably an alkyl group, an alkoxy group, an aromatic hydrocarbon group, or an aromatic heterocyclic group. From the viewpoint of charge transport property, the substituent is preferably an aromatic hydrocarbon group or an aromatic heterocyclic group, more preferably an aromatic hydrocarbon group, and further preferably has no substituent. From the viewpoint of improving solubility, an alkyl group or an alkoxy group is preferable as a substituent.

Each substituent of the substituent group Q may further have a substituent. Examples of the substituent include the same groups as those described for the substituent (substituent group Q). Each substituent of the substituent group Q may further have an alkyl group having 8 or less carbon atoms, an alkoxy group having 8 or less carbon atoms, or a phenyl group, and more preferably an alkyl group having 6 or less carbon atoms, an alkoxy group having 6 or less carbon atoms, or a phenyl group. From the viewpoint of charge transport property, each substituent of the substituent group Q more preferably has no further substituent.

R in formula (1-1) or formula (1-2) disclosed later ¹¹ As described below.

＜R ¹¹ ＞

R in formula (1-1) or formula (1-2) ¹¹ Each independently is a hydrogen atom or a substituent.

As substituents other than hydrogen atoms, R ¹¹ Examples thereof include groups selected from the substituent group Q. The substituent group Q is also preferably an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent or an aromatic heterocyclic group having 3 to 30 carbon atoms which may have a substituent. From the viewpoints of improvement in durability and charge transport property, an aromatic hydrocarbon group which may have a substituent is further preferable. R when plural substituents are present in the formula (1-1) or the formula (1-2) ¹¹ In the case of (1), a plurality of R ¹¹ May be the same or different from each other.

As the aromatic hydrocarbon group having 6 to 30 carbon atomsA substituent which may be present, a substituent which may be present in an aromatic heterocyclic group having 3 to 30 carbon atoms, R as a substituent ¹¹ And optionally a substituent selected from the group Q of substituents.

[ Compound (1-1) ]

The compound (1-1) is a compound represented by the following formula (1-1).

[ chemical 6]

(in the formula (1-1),

W ₁ 、W ₂ w and W ₃ Each independently represents-CH or a nitrogen atom, W ₁ 、W ₂ W and W ₃ At least one of which is a nitrogen atom,

Xa ¹ 、Ya ¹ and Za ¹ Each independently represents a 1, 3-phenylene group which may have a substituent or a 1, 4-phenylene group which may have a substituent,

Za ¹ At least one of which is a 1, 3-phenylene group,

Xa ² ya ² Each independently represents a phenyl group which may have a substituent,

Za ² represents an N-carbazolyl group which may have a substituent,

f11 is either 1 or 2,

g11 is an integer of 1 to 5,

h11 is an integer of 2 to 5,

j11 is an integer of 1 to 6,

f11+g11+h11+j11 is 5 or more,

R ¹¹ each independently represents a hydrogen atom or a substituent. )

＜W ₁ 、W ₂ 、W ₃ ＞

W in formula (1-1) ₁ 、W ₂ W and W ₃ Each independently represents-CH or a nitrogen atom, W ₁ 、W ₂ W and W ₃ At least one of which is a nitrogen atom. From the viewpoint of electron transport property and electron durability, it is preferably at least W ₁ Is a nitrogen atom, more preferably at least W ₁ W and W ₂ Is a nitrogen atom, more preferably W ₁ 、W ₂ W and W ₃ All nitrogen atoms.

That is, from the viewpoint of improving electron transport properties, it is preferable that the group bonded at the para-position is bonded to two or three benzene rings at the para-position to expand the conjugation of W ₁ Is a nitrogen atom, further preferably except W ₁ W other than ₂ Or W ₃ One of which is a pyrimidine structure having a nitrogen atom, most preferably W ₁ 、W ₂ W and W ₃ Triazine structures all of which are nitrogen atoms.

＜-(Xa ¹ ) _g11 -Xa ² ＞

In the formula (1-1) - (Xa) ¹ ) _g11 -Xa ² Preferably selected from the following structures.

[ chemical 7]

In these structures, the hydrogen atom may also be substituted by a substituent selected from substituent group Q. Preferably, the hydrogen atom is an unsubstituted structure.

＜-(Ya ¹ ) _h11 -Ya ² ＞

In the formula (1-1) - (Ya) ¹ ) _h11 -Ya ² Preferably selected from the following structures.

[ chemical 8]

In these structures, the hydrogen atom may be substituted with a substituent selected from substituent group Q. Preferably, the hydrogen atom is an unsubstituted structure.

＜-(Za ¹ ) _j11 -Za ² ＞

In the formula (1-1) - (Za) ¹ ) _j11 -Za ² Preferably selected from the following structures.

[ chemical 9]

In these structures, the hydrogen atom may also be substituted with a substituent selected from substituent group Q. Preferably, the hydrogen atom is an unsubstituted structure.

< molecular weight of Compound (1-1) >)

The molecular weight of the compound (1-1) is preferably 3000 or less, more preferably 2500 or less, particularly preferably 2000 or less, and most preferably 1800 or less. The lower limit of the molecular weight of the compound (1-1) is preferably 930 or more, more preferably 1000 or more, particularly preferably 1200 or more.

Specific examples of the compound (1-1)

The specific structure of the compound (1-1) is not particularly limited, and examples thereof include the following compounds.

[ chemical 10]

[ chemical 11]

[ chemical 12]

[ chemical 13]

[ chemical 14]

[ 15]

[ 16]

[ chemical 17]

Process for producing Compound (1-1)

The compound (1-1) can be produced, for example, by the method described in examples.

< reason why Compound (1-1) exerts an effect >

In the compound (1-1), W ₁ The group bonded to the para position of (a) is bonded to two or three benzene rings at the para position to expand the conjugation, and it is considered that the lowest unoccupied molecular orbital (lowest unoccupied molecular orbital, LUMO) is distributed therein, and thus the electron transport property is excellent. In addition, it is considered that the reason is that ₁ Since the number of benzene rings bonded by para-conjugation is three or less, conjugation is not excessively long, and the light-emitting material has a wide energy gap, and when the light-emitting material is used as a host material for a light-emitting layer, it is preferable that the light-emitting material is not easily quenched. The compound (1-1) has at least one carbazolyl group and therefore has excellent resistance to alcohol solvents after film formation.

In the compound (1-1) containing W ₁ 、W ₂ W and W ₃ In the nitrogen-containing 6-membered ring of W ₃ The group bonded to the para position of (2) is 1, 3-phenylene and is therefore unconjugated. Therefore, it is considered that the compound (1-1) has a wide energy gap, and when it is used as a host material for a light-emitting layer, it is preferable that the light-emitting material is not easily quenched.

Za of Compound (1-1) ¹ At least one of (2) is 1, 3-phenylene and is therefore not associated with Za as a carbazolyl group ² Conjugation. Therefore, the compound (1-1) is considered to have a wide energy gap for use as a light-emitting layerIn the case of the host material, the light-emitting material is preferably not easily quenched.

Further, if- (Xa) ¹ ) _g11 -Xa ² 、-(Ya ¹ ) _h11 -Ya ² 、-(Za ¹ ) _j11 -Za ² In the preferred structure, the light-emitting material has a wide energy gap, and when the light-emitting material is used as a host material for a light-emitting layer, the light-emitting material is not easily quenched.

In addition, the compound (1-1) moderately contains a large amount of 1, 3-phenylene groups and does not contain a 1, 4-phenylene linking structure longer than a terphenyl (terphenyl) group, and thus is excellent in solubility. On the other hand, f11+g11+h11+j11 is 5 or more, and is considered to be hardly soluble in an alcohol solvent after film formation, that is, to have solvent resistance. F11+g11+h11+j11 is preferably 7 or more, more preferably 9 or more from the viewpoint of solvent resistance to an alcohol solvent after film formation, and is preferably 15 or less from the viewpoint of stability.

In addition, the compound (1-1) is represented by Za ² Since the N-carbazolyl group is present, the intermolecular interaction is enhanced, and the solvent resistance is excellent, and in particular, the solvent resistance is high relative to an alcohol solvent.

[ Compound (1-2) ]

The compound (1-2) is a compound represented by the following formula (1-2).

[ chemical 18]

(in the formula (1-2),

Ya ¹ za and Za ¹ At least one of (2) is a 1, 3-phenylene group which may have a substituent,

Xa ² represents a phenyl group which may have a substituent(s),

Ya ² za and Za ² Each independently represents an N-carbazolyl group which may have a substituent,

f11 is either 1 or 2,

g11 is an integer of 1 to 5,

h11 is an integer of 2 to 5,

j11 is an integer of 2 to 5,

f11+g11+h11+j11 is 6 or more,

R ¹¹ each independently represents a hydrogen atom or a substituent. )

＜W ₁ 、W ₂ 、W ₃ ＞

W in the formula (1-2) ₁ 、W ₂ W and W ₃ Each independently represents-CH or a nitrogen atom, W ₁ 、W ₂ W and W ₃ At least one of which is a nitrogen atom. From the viewpoint of electron transport property and electron durability, it is preferably at least W ₁ Is a nitrogen atom, more preferably at least W ₁ W and W ₂ Is a nitrogen atom, more preferably W ₁ 、W ₂ W and W ₃ All nitrogen atoms.

That is, from the viewpoint of improving electron transport properties, it is preferable that W is a group bonded at the para position, wherein two or three benzene rings are bonded at the para position to expand the conjugation ₁ Is a nitrogen atom, more preferably W ₁ W is provided ₂ Or W ₃ Pyrimidine structures in which one of them is a nitrogen atom, most preferably W ₁ 、W ₂ W and W ₃ Triazine structures all of which are nitrogen atoms.

＜-(Xa ¹ ) _g11 -Xa ² ＞

- (Xa) in the formula (1-2) ¹ ) _g11 -Xa ² Preferably selected from the following structures.

[ chemical 19]

＜-(Ya ¹ ) _h11 -Ya ² ＞

- (Ya) in the formula (1-2) ¹ ) _h11 -Ya ² Preferably selected from the following structures.

[ chemical 20]

In these structures, ya is included as ² The hydrogen atoms on all benzene rings, including the hydrogen atoms on the benzene ring of the N-carbazolyl group, may be substituted with a substituent selected from substituent group Q. Preferably, the hydrogen atom is an unsubstituted structure.

＜-(Za ¹ ) _j11 -Za ² ＞

- (Za) in the formula (1-2) ¹ ) _j11 -Za ² The following structures are preferred.

[ chemical 21]

In these structures, as Za ² The hydrogen atoms on all benzene rings, including the hydrogen atoms on the benzene ring of the N-carbazolyl group, may be substituted with a substituent selected from substituent group Q. Preferably, the hydrogen atom is an unsubstituted structure.

Preferred Structure of Compound (1-2)

In the formula (1-2), h11 is preferably 2 or more, more preferably 2 or 4.

Further, j11 is preferably 2 or more, more preferably 2 or 4.

When h11 and j11 are equal to or higher than the lower limit, the solubility becomes good and the stability becomes good.

Xa in the formula (1-2) ¹ At least one of (C) is preferably 1, 3-phenylene, more preferably Xa ¹ All being 1, 3-phenylene. By Xa ¹ The conjugated structure is 1, 3-phenylene, so that the conjugation is broken and the solubility is improved.

In the formula (1-2), ya is ¹ Is preferably 1, 3-phenylene, more preferably Ya ¹ All being 1, 3-phenylene. By Ya ¹ The conjugated structure is 1, 3-phenylene, so that the conjugation is broken and the solubility is improved.

In the formula (1-2), za ¹ At least one of (3) is preferably 1, 3-phenylene, more preferably Za ¹ All being 1, 3-phenylene. By Za ¹ The conjugated structure is 1, 3-phenylene, so that the conjugation is broken and the solubility is improved.

< molecular weight of Compound (1-2) >)

The molecular weight of the compound (1-2) is preferably 3000 or less, more preferably 2500 or less, particularly preferably 2000 or less, and most preferably 1800 or less. The lower limit of the molecular weight of the compound (1-2) is preferably 930 or more, more preferably 1000 or more, particularly preferably 1200 or more.

Specific examples of the compound (1-2)

The specific structure of the compound (1-2) is not particularly limited, and examples thereof include the following compounds.

[ chemical 22]

[ chemical 23]

[ chemical 24]

[ chemical 25]

[ chemical 26]

[ chemical 27]

[ chemical 28]

[ chemical 29]

< method for producing Compound (1-2) >)

The compound (1-2) can be produced, for example, by the method described in examples disclosed below.

< reason why Compound (1-2) exerts an effect >

In the compound (1-2), W ₁ Since the group bonded to the para position of (a) is a group in which two or three benzene rings are bonded to the para position, the conjugated structure is extended, and the Lowest Unoccupied Molecular Orbital (LUMO) is thought to be distributed therein, so that the electron transport property is excellent. In addition, it is considered that the reason is that ₁ The number of benzene rings bonded by para-conjugation is three or less, so that conjugation is not too long, and the light-emitting material is preferably not easily quenched when the light-emitting material is used as a host material for a light-emitting layer. The compound (1-2) has at least two carbazolyl groups and therefore has excellent resistance to alcohol solvents after film formation.

Containing W in Compound (1-2) ₁ 、W ₂ W and W ₃ In the nitrogen-containing 6-membered ring of W ₃ The group bonded to the para position of (2) is 1, 3-phenylene and is therefore unconjugated. Therefore, it is considered that the compound (1-2) has a wide energy gap, and when it is used as a host material for a light-emitting layer, it is preferable that the light-emitting material is not easily quenched.

Ya of Compound (1-2) ¹ Za and Za ¹ At least one of each is a 1, 3-phenylene group and thus is not compatible with Ya as an N-carbazolyl group ² Or Za ² Conjugation. Therefore, it is considered that the compound (1-2) has a wide energy gap, and when it is used as a host material for a light-emitting layer, it is preferable that the light-emitting material is not easily quenched.

Further, if- (Xa) ¹ ) _g11 -Xa ² 、-(Ya ¹ ) _h11 -Ya ² 、-(Za ¹ ) _j11 -Za ² In the preferred structure, the light-emitting layer has a wide energy gap, and when the light-emitting layer is used as a host material, the light-emitting material is not easily quenched.

In addition, the compound (1-2) contains W ₁ 、W ₂ W and W ₃ The phenylene group between the nitrogen-containing 6-membered ring and the carbazolyl group is three or more, and is excellent in solubility because it moderately contains a large amount of 1, 3-phenylene groups and does not contain a 1, 4-phenylene linkage structure longer than that of the terphenyl group. On the other hand, f11+g11+h11+j11 is 6 or more, and is considered to be hardly soluble in an alcohol solvent after film formation, that is, to have solvent resistance. F11+g11+h11+j11 is preferably 7 or more, more preferably 9 or more from the viewpoint of solvent resistance to an alcohol solvent after film formation, and is preferably 15 or less from the viewpoint of stability.

In addition, the compound (1-2) is represented by Ya ² Za and Za ² Since the N-carbazolyl group is present, the intermolecular interaction is enhanced, and the solvent resistance is excellent, and in particular, the solvent resistance is high relative to an alcohol solvent.

[ composition ]

The composition of the present invention comprises at least the compound of the present invention and an organic solvent.

The composition of the present invention may contain only one kind of compound (1-1) or two or more kinds thereof.

The composition of the present invention may contain only one kind of compound (1-2), or may contain two or more kinds.

One or more compounds (1-1) and one or more compounds (1-2) may also be contained in the composition of the present invention.

The composition of the present invention preferably further comprises a light-emitting material, and is suitably used as a composition for forming a light-emitting layer of an organic electroluminescent element.

[ organic solvent ]

The organic solvent contained in the composition of the present invention is a volatile liquid component for forming a layer containing the 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 compound of the present invention and a luminescent material described later are well dissolved as a solute.

Examples of the preferable organic solvents include: alkanes such as n-decane, cyclohexane, ethylcyclohexane, decalin and bicyclohexane; aromatic hydrocarbons such as toluene, xylene, mesitylene, phenylcyclohexane, tetrahydronaphthalene, and methylnaphthalene; halogenated aromatic hydrocarbons such as chlorobenzene, dichlorobenzene, trichlorobenzene, etc.; aromatic ethers such as 1, 2-dimethoxybenzene, 1, 3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2, 3-dimethyl anisole, 2, 4-dimethyl anisole, 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 fenchyl ketone (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, propylene glycol-1-monomethyl ether acetate (PGMEA), and the like.

Among these, from the viewpoints 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 particularly preferable.

These organic solvents may be used singly or in combination of two or more kinds in proportion.

The boiling point of the organic solvent used is usually 80℃or higher, preferably 100℃or higher, more preferably 120℃or higher, usually 380℃or lower, preferably 350℃or lower, more preferably 330℃or lower. If the boiling point of the organic solvent is lower than this range, the film formation stability may be lowered due to evaporation of the solvent from the composition during wet film formation. If the boiling point of the organic solvent exceeds this range, there is a possibility that the film formation stability may be lowered due to the solvent remaining after the film formation during the wet film formation.

In particular, by combining two or more organic solvents having a boiling point of 150 ℃ or higher among the above organic solvents, a uniform coating film can be produced. If the organic solvent having a boiling point of 150 ℃ or higher is one or less, a uniform film may not be formed at the time of coating.

[ luminescent Material ]

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

As the light emitting material, a known material can be used, and a fluorescent light emitting material or a phosphorescent light emitting material can be used alone or in combination of two or more. Phosphorescent materials are preferred from the viewpoint of internal quantum efficiency.

< phosphorescent Material >)

The phosphorescent material is a material which exhibits luminescence from an excited triplet state. For example, a metal complex compound having Ir, pt, eu, or the like is typical, and a material structure including a metal complex is preferable.

Among the metal complexes, phosphorescent organometallic complexes that emit light through a triplet state include wiener (Werner) type complexes or organometallic complex compounds containing a metal selected from groups 7 to 11 of the long periodic table (hereinafter, unless otherwise limited, the term "periodic table" is used to refer to the long periodic table) as a central metal. The phosphorescent material is preferably a compound represented by the following formula (201) or a compound represented by the following formula (205), and more preferably a compound represented by the following formula (201).

[ chemical 30]

In the formula (201), M is a metal selected from groups 7 to 11 of the periodic Table, and examples thereof include: ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum, gold, europium.

The ring A1 represents an aromatic hydrocarbon ring structure which may have a substituent or an aromatic heterocyclic structure which may have a substituent.

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

R ²⁰¹ 、R ²⁰² Each independently is a structure represented by the formula (202), "x" represents a bonding position to the ring A1 or the ring A2. R is R ²⁰¹ 、R ²⁰² May be the same or different. At R ²⁰¹ 、R ²⁰² Where there are plural, respectively, these may be the same or different.

Ar in formula (202) ²⁰¹ 、Ar ²⁰³ Each independently represents an aromatic hydrocarbon ring structure which may have a substituent, or an aromatic heterocyclic structure which may have a substituent.

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

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

B ²⁰¹ -L ²⁰⁰ -B ²⁰² A bidentate ligand representing an anionic nature. B (B) ²⁰¹ B (B) ²⁰² Each independently represents a carbon atom, an oxygen atom or a nitrogen atom. These atoms may be atoms constituting a ring. L (L) ²⁰⁰ Represents a single bond, or B ²⁰¹ B (B) ²⁰² Together forming a group of bidentate ligands. In the presence of a plurality of B ²⁰¹ -L ²⁰⁰ -B ²⁰² These may be the same or different.

In the formulas (201) and (202), i1 and i2 each independently represent an integer of 0 to 12 inclusive.

i3 is Ar which is capable of ²⁰² The number of substitutions is an integer of 0 or more as the upper limit.

j is Ar which can be selected from ²⁰¹ The number of substitutions is an integer of 0 or more as the upper limit.

k1 and k2 are each independently an integer of 0 or more, the upper limit of which is the number of rings A1 and A2 that can be substituted.

m is an integer of 1 to 3.

The aromatic hydrocarbon ring in the ring A1 is preferably an aromatic hydrocarbon ring having 6 to 30 carbon atoms, and specifically, a benzene ring, a naphthalene ring, an anthracene ring, a triphenyl ring, an acenaphthene ring, a fluoranthene ring, or a fluorene ring is preferable.

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

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

The aromatic heterocyclic ring in the ring A2 is preferably an aromatic heterocyclic ring having 3 to 30 carbon atoms and containing any one of a nitrogen atom, an oxygen atom and a sulfur atom as a hetero atom,

Specifically, there may be mentioned: pyridine ring, pyrimidine ring, pyrazine ring, triazine ring, imidazole ring, oxazole ring, thiazole ring, benzothiazole ring, benzoxazole ring, benzimidazole ring, quinoline ring, isoquinoline ring, quinoxaline ring, quinazoline ring, naphthyridine ring, phenanthridine ring,

more preferably 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, a quinazoline ring,

further preferred are a pyridine ring, an imidazole ring, a benzothiazole ring, a quinoline ring, an isoquinoline ring, a quinoxaline ring, a quinazoline ring,

most preferred are pyridine ring, imidazole ring, benzothiazole ring, quinoline ring, quinoxaline ring, quinazoline ring.

The preferable combination of the ring A1 and the ring A2 is (benzene ring-pyridine ring), (benzene ring-quinoline ring), (benzene ring-quinoxaline ring), (benzene ring-quinazoline ring), (benzene ring-imidazole ring), or (benzene ring-benzothiazole ring) when expressed as (ring A1-ring A2).

The substituents which the rings A1 and A2 may have may be arbitrarily selected, and are preferably one or more substituents selected from the substituent group S described below.

In Ar ²⁰¹ 、Ar ²⁰² 、Ar ²⁰³ In the case where any of the aromatic hydrocarbon ring structures which may have a substituent is used, the aromatic hydrocarbon ring structure is preferably an aromatic hydrocarbon ring having 6 to 30 carbon atoms,

Specifically, benzene ring, naphthalene ring, anthracene ring, triphenyl ring, acenaphthene ring, fluoranthene ring, fluorene ring are preferable,

more preferably a benzene ring, a naphthalene ring, and a fluorene ring,

most preferably a benzene ring.

In Ar ²⁰¹ 、Ar ²⁰² 、Ar ²⁰³ In the case where any one of the fluorene rings may have a substituent, the 9-position and 9' -position of the fluorene ring are preferably substituted or bonded to adjacent structures.

In Ar ²⁰¹ 、Ar ²⁰² 、Ar ²⁰³ In the case where any one of the benzene rings which may have a substituent is a benzene ring, at least one benzene ring is preferably bonded to an adjacent structure in the ortho-position or meta-position, and more preferably at least one benzene ring is bonded to an adjacent structure in the meta-position.

In Ar ²⁰¹ 、Ar ²⁰² 、Ar ²⁰³ In the case where any one of the heterocyclic aromatic structures which may have a substituent(s), the heterocyclic aromatic structure is preferably a 3 to 30 carbon-atom-containing heterocyclic aromatic ring containing any one of a nitrogen atom, an oxygen atom and a sulfur atom as a hetero atom,

specifically, there may be mentioned: pyridine ring, pyrimidine ring, pyrazine ring, triazine ring, imidazole ring, oxazole ring, thiazole ring, benzothiazole ring, benzoxazole ring, benzimidazole ring, quinoline ring, isoquinoline ring, quinoxaline ring, quinazoline ring, naphthyridine ring, phenanthridine ring, carbazole ring, dibenzofuran ring, dibenzothiophene ring,

Preferably a pyridine ring, pyrimidine ring, triazine ring, carbazole ring, dibenzofuran ring, dibenzothiophene ring.

In Ar ²⁰¹ 、Ar ²⁰² 、Ar ²⁰³ In the case where any one of the carbazole rings may have a substituent, the N-position of the carbazole ring is preferably a substituent or bonded to an adjacent structure.

In Ar ²⁰² In the case of an aliphatic hydrocarbon structure which may have a substituent, the aliphatic hydrocarbon structure is an aliphatic hydrocarbon structure having a straight chain, a branched chain, or a cyclic structure, preferably an aliphatic hydrocarbon having 1 to 24 carbon atoms, more preferably an aliphatic hydrocarbon having 1 to 12 carbon atoms, and still more preferably an aliphatic hydrocarbon having 1 to 8 carbon atoms.

i1 and i2 are each independently an integer of 0 to 12, preferably an integer of 1 to 12, more preferably an integer of 1 to 8, and even more preferably an integer of 1 to 6. Within this range, the solubility and charge transport properties are expected to be improved.

i3 is preferably an integer of 0 to 5, more preferably an integer of 0 to 2, and even more preferably 0 or 1.

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

k1 and k2 are each independently an integer of preferably 0 to 3, more preferably an integer of 1 to 3, further preferably 1 or 2, and particularly preferably 1.

Ar ²⁰¹ 、Ar ²⁰² 、Ar ²⁰³ The substituent may be optionally selected, but is preferably one or more substituents selected from the substituent group S described later, more preferably a hydrogen atom, an alkyl group, an aryl group, particularly preferably a hydrogen atom, an alkyl group, and most preferably unsubstituted (hydrogen atom).

When not specifically described, the substituent is preferably a group selected from the following substituent groups S.

Substituent group S >

Alkyl group is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms, still more preferably an alkyl group having 1 to 8 carbon atoms, and particularly preferably an alkyl group having 1 to 6 carbon atoms.

Alkoxy groups are preferably alkoxy groups having 1 to 20 carbon atoms, more preferably alkoxy groups having 1 to 12 carbon atoms, and still more preferably alkoxy groups having 1 to 6 carbon atoms.

The aryloxy group is preferably an aryloxy group having 6 to 20 carbon atoms, more preferably an aryloxy group having 6 to 14 carbon atoms, still more preferably an aryloxy group having 6 to 12 carbon atoms, particularly preferably an aryloxy group having 6 carbon atoms.

The heteroaryloxy group is preferably a heteroaryloxy group having 3 to 20 carbon atoms, more preferably a heteroaryloxy group having 3 to 12 carbon atoms.

An alkylamino group is preferably an alkylamino group having 1 to 20 carbon atoms, more preferably an alkylamino group having 1 to 12 carbon atoms.

Arylamine groups are preferably arylamine groups having 6 to 36 carbon atoms, more preferably arylamine groups having 6 to 24 carbon atoms.

Aralkyl group is preferably an aralkyl group having 7 to 40 carbon atoms, more preferably an aralkyl group having 7 to 18 carbon atoms, and still more preferably an aralkyl group having 7 to 12 carbon atoms.

The heteroarylalkyl group is preferably a heteroarylalkyl group having 7 to 40 carbon atoms, more preferably a heteroarylalkyl group having 7 to 18 carbon atoms.

Alkenyl is preferably an alkenyl group having 2 to 20 carbon atoms, more preferably an alkenyl group having 2 to 12 carbon atoms, still more preferably an alkenyl group having 2 to 8 carbon atoms, and particularly preferably an alkenyl group having 2 to 6 carbon atoms.

Alkynyl is preferably an alkynyl group having 2 to 20 carbon atoms, more preferably an alkynyl group having 2 to 12 carbon atoms.

Aryl is preferably an aryl group having 6 to 30 carbon atoms, more preferably an aryl group having 6 to 24 carbon atoms, still more preferably an aryl group having 6 to 18 carbon atoms, and particularly preferably an aryl group having 6 to 14 carbon atoms.

Heteroaryl is preferably a heteroaryl group having 3 to 30 carbon atoms, more preferably a heteroaryl group having 3 to 24 carbon atoms, still more preferably a heteroaryl group having 3 to 18 carbon atoms, and particularly preferably a heteroaryl group having 3 to 14 carbon atoms.

Alkylsilane group, preferably alkylsilane group having 1 to 20 carbon atoms in the alkyl group, more preferably alkylsilane group having 1 to 12 carbon atoms in the alkyl group.

Arylsilane groups, preferably arylsilane groups having 6 to 20 carbon atoms of the aryl group, more preferably arylsilane groups having 6 to 14 carbon atoms of the aryl group.

Alkylcarbonyl group, preferably alkylcarbonyl group having 2 to 20 carbon atoms.

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

More than one hydrogen atom in the above groups may be substituted with a fluorine atom, or more than one hydrogen atom may be substituted with a deuterium atom.

Hydrogen atom, deuterium atom, fluorine atom, cyano group, or-SF ₅ 。

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

(preferred groups in substituent group S)

In these substituent groups S,

preferably alkyl, alkoxy, aryloxy, arylamino, aralkyl, alkenyl, aryl, heteroaryl, alkylsilane, arylsilane, a group in which one or more hydrogen atoms of these groups are replaced with fluorine atoms, a fluorine atom, cyano, or-SF ₅ ，

More preferably alkyl, arylamino, aralkyl, alkenyl, aryl, heteroaryl, groups in which one or more hydrogen atoms of these groups are replaced with fluorine atoms, cyano groups, or-SF ₅ ，

Further preferred are alkyl, alkoxy, aryloxy, arylamino, aralkyl, alkenyl, aryl, heteroaryl, alkylsilane, arylsilane,

particularly preferred are alkyl, arylamine, aralkyl, alkenyl, aryl, heteroaryl,

most preferred are alkyl, arylamino, aralkyl, aryl, heteroaryl groups.

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

(preferred Structure of formula (201))

In the structure represented by the formula (202) in the formula (201), it is preferable that

(i) Structure having benzene ring-linked group

(ii) Having a structure in which an aromatic hydrocarbon group or an aromatic heterocyclic group having an alkyl group or an aralkyl group bonded to the ring A1 or the ring A2

(iii) A dendritic structure is bonded to the ring A1 or the ring A2.

(i) Ar in the structure having a benzene ring-bonded group ²⁰¹ Is a benzene ring structure, i1 is 1-6, and at least one benzene ring is bonded with an adjacent structure at an ortho-position or a meta-position.

With this structure, it is expected to improve solubility and charge transport properties.

(ii) Ar in the structure having an aromatic hydrocarbon group or an aromatic heterocyclic group to which an alkyl group or an aralkyl group is bonded to the ring A1 or the ring A2 ²⁰¹ Is an aromatic hydrocarbon structure or an aromatic heterocyclic structure, i1 is 1 to 6, ar ²⁰² Is aliphatic hydrocarbon structure, i2 is 1-12, preferably 3-8, ar ²⁰³ Is benzene ring structure, i3 is 0 or 1.

In the case of this structure, ar is preferable ²⁰¹ The aromatic hydrocarbon structure is more preferably a structure in which one to five benzene rings are bonded, and is more preferably one benzene ring.

(iii) Ar in the dendritic structure bonded to ring A1 or ring A2 ²⁰¹ 、Ar ²⁰² Is of benzene ring structure, ar ²⁰³ Is biphenyl or terphenyl structure, i1 and i2 are 1-6, i3 is 2, j is 2.

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

[ 31]

In the formula (203), R ²¹¹ 、R ²¹² 、R ²¹³ Represents a substituent.

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

[ chemical 32]

In the formula (204), the ring B3 represents an aromatic heterocyclic structure containing a nitrogen atom which may have a substituent. Ring B3 is preferably a pyridine ring.

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

The phosphorescent material represented by the above formula (201) is not particularly limited, and the following structures are specifically exemplified.

Hereinafter, me means a methyl group, and Ph means a phenyl group.

[ 33]

[ chemical 34]

[ 35]

[ 36]

/>

Next, a compound represented by the following formula (205) will be described.

[ 37]

In the formula (205), M ² Representing a metal. T represents a carbon atom or a nitrogen atom. R is R ⁹² ～R ⁹⁵ Each independently represents a substituent. Wherein, in the case where T is a nitrogen atom, R is absent ⁹⁴ R is R ⁹⁵ 。

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

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

Further, in the case where T is a carbon atom, R ⁹⁴ R is R ⁹⁵ Respectively and independently represent R ⁹² R is R ⁹³ Substituents indicated by the same illustrative examples. In the case where T is a nitrogen atom, there is no R directly bonded to the T ⁹⁴ Or R is ⁹⁵ 。

R ⁹² ～R ⁹⁵ May further have a substituent. The substituent may be R ⁹² R is R ⁹³ And the substituents listed. Further, R ⁹² ～R ⁹⁵ Any two or more of the groups may be linked 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, particularly preferably 3000 or less. The molecular weight of the phosphorescent material is usually 1000 or more, preferably 1100 or more, and more preferably 1200 or more. It is considered that, in this molecular weight range, the phosphorescent light-emitting materials are not aggregated with each other and are uniformly mixed with the compound and/or other charge transport material of the present invention, whereby a light-emitting layer having high light-emitting efficiency can be obtained.

The molecular weight of the phosphorescent material is preferably large in terms of high Tg, melting point, decomposition temperature, etc., excellent heat resistance of the phosphorescent material and the formed light-emitting layer, less occurrence of degradation of film quality due to gas generation, recrystallization, migration of molecules, etc., increase in impurity concentration accompanying thermal decomposition of the material, etc. The molecular weight of the phosphorescent material is preferably small in terms of easy purification of the organic compound.

[ Charge transport Material ]

When the composition of the present invention is a composition for forming a light-emitting layer, it is preferable that a charge transport material other than the compound of the present invention is contained as a further host material in addition to the compound of the present invention.

The charge transport material used as the host material of the light-emitting layer is a material having a skeleton excellent in charge transport property, and is preferably selected from electron transport materials, hole transport materials, and bipolar materials capable of transporting both electrons and holes. Further, in the present invention, the charge transport material means a material which also includes a material for adjusting charge transport property.

Specific examples of the skeleton having excellent charge transport properties include: aromatic structures, aromatic amine structures, triarylamine structures, dibenzofuran structures, naphthalene structures, phenanthrene structures, phthalocyanine structures, porphyrin structures, thiophene structures, benzyl phenyl structures, fluorene structures, quinacridone structures, benzophenanthrene structures, carbazole structures, pyrene structures, anthracene structures, phenanthroline structures, quinoline structures, pyridine structures, pyrimidine structures, triazine structures, oxadiazole structures, imidazole structures, or the like.

In the composition of the present invention, the compound of the present invention functions as an electron transporting material, and therefore, it is preferable to further contain a hole transporting material as a charge transporting material. The hole-transporting material is a compound having a structure excellent in hole-transporting property, and in the skeleton excellent in charge-transporting property, the structure excellent in hole-transporting property is preferably a carbazole structure, a dibenzofuran structure, a triarylamine structure, a naphthalene structure, a phenanthrene structure, or a pyrene structure, and more preferably a carbazole structure, a dibenzofuran structure, or a triarylamine structure. The compound represented by the following formula (240) is particularly preferred.

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, more preferably a compound having a condensed ring structure of two or more three or more or a compound having at least one condensed ring of five or more. By being these compounds, the following effects are easily obtained: the rigidity of the molecule increases and suppresses the extent of molecular movement in response to heat. Further, in terms of charge transport property and durability of the material, it is preferable that the condensed rings of three or more rings and the condensed rings of five or more rings have an aromatic hydrocarbon ring or an aromatic heterocyclic ring.

Specific examples of the condensed ring structure having three or more rings include: an anthracene structure, a phenanthrene structure, a pyrene structure,Structure, naphthacene structure, benzophenanthrene structure, fluorene structure, benzofluorene structure, indenofluorene structure, indolofluorene structure, carbazole structure, indenocarbazole structure, indolocarbazole structure, dibenzofuran structure, dibenzothiophene structure, and the like.

From the viewpoints of charge transport property and solubility, at least one selected from the group consisting of a phenanthrene structure, a fluorene structure, an indenofluorene structure, a carbazole structure, an indenocarbazole structure, an indolocarbazole structure, a dibenzofuran structure, and a dibenzothiophene structure is preferable. From the viewpoint of durability with respect to electric charges, a carbazole structure or an indolocarbazole structure is further preferable.

Among the charge transport materials used as the host material of the light-emitting layer, a compound having a structure in which a plurality of benzene rings are linked, that is, a compound represented by the following formula (260), is preferable as a material for adjusting charge transport properties. It is considered that the inclusion of the compound as a host material allows the exciton generated in the light-emitting layer to recombine well and thus improves the light-emitting efficiency, and that the charge transport property in the light-emitting layer is appropriately adjusted, so that the deterioration of the light-emitting material is suppressed and the driving life is prolonged.

When the composition of the present invention is a composition for forming a light-emitting layer, it is preferable that the composition of the present invention contains a compound represented by the following formula (240) and/or a compound represented by the following formula (260) in addition to the compound of the present invention having excellent electron transport properties. Such a compound is preferably contained as a further host material from the viewpoint of charge balance adjustment in the light-emitting layer and the viewpoint of light-emitting 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. The light-emitting layer formed using a material having excellent flexibility is preferably a light-emitting layer of an organic electroluminescent element 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 still more preferably 10,000 or more and 100,000 or less.

The charge transport material used as the host material of the light-emitting layer is preferably low-molecular from the viewpoints of ease of synthesis and purification, ease of design of electron transport performance and hole transport performance, and ease of viscosity adjustment when dissolved in an organic solvent. When the charge transport material used as the host material included in the light-emitting layer is a low-molecular material, the molecular weight is preferably 5,000 or less, more preferably 4,000 or less, particularly preferably 3,000 or less, most preferably 2,000 or less, usually 800 or more, and preferably 900 or more. When a layer formed so as to contact with the light-emitting layer is formed by a wet film formation method, the molecular weight of the charge transport material is preferably 1000 or more, more preferably 1100 or more, and particularly preferably 1200 or more.

< Compound represented by formula (240) >)

[ 38]

(in the formula (240),

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

R ⁶¹¹ 、R ⁶¹² Each independently represents 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 、n ⁶¹² Each independently is an integer of 0 to 4. )

(Ar ⁶¹¹ 、Ar ⁶¹² )

The number of carbon atoms of the aromatic hydrocarbon group is usually 6 to 50, preferably 6 to 30, more preferably 6 to 18. Specific examples of the aromatic hydrocarbon group include benzene ring, naphthalene ring, anthracene ring, tetralin ring, phenanthrene ring,A monovalent group having an aromatic hydrocarbon structure in which a carbon number of a ring, a pyrene ring, a benzanthracene ring, a perylene ring or the like is usually 6 or more and usually 30 or less, preferably 18 or less, more preferably 14 or less, or a monovalent group having a structure in which a plurality of structures selected from these structures are bonded in a chain or branched manner. When a plurality of aromatic hydrocarbon rings are linked, a structure in which two to eight are linked is usually used, and a structure in which two to five are linked is preferable. In aromatic hydrocarbon ringsIn the case of connecting a plurality of the structures, the same structure may be linked, or different structures may be linked.

Ar ⁶¹¹ 、Ar ⁶¹² Preferably each independently of the other

Phenyl group,

A monovalent group in which a plurality of benzene rings are bonded in a chain or branched manner,

one or more benzene rings and at least one naphthalene ring are bonded in a chain or branched manner,

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

One or more benzene rings and at least one tetraextending benzene ring are bonded in a chain or branched manner,

more preferably, the monovalent group is a monovalent group in which a plurality of benzene rings are bonded in a chain or branched manner. In any case, the order of bonding is not problematic.

Ar ⁶¹¹ 、Ar ⁶¹² Particularly, a monovalent group in which a plurality of benzene rings which may have a substituent are bonded to each other in a chain or branched manner is preferable, and a monovalent group in which a plurality of benzene rings are bonded to each other in a chain or branched manner is most preferable.

The number of benzene rings, naphthalene rings, phenanthrene rings and tetra-extended benzene rings bonded is usually 2 to 8, preferably 2 to 5, as described above. Among them, a monovalent group having one to four benzene rings attached thereto, a monovalent group having one to four benzene rings and naphthalene rings attached thereto, a monovalent group having one to four benzene rings and phenanthrene rings attached thereto, or a monovalent group having one to four benzene rings and tetralin rings attached thereto is preferable.

These aromatic hydrocarbon groups may have a substituent. The substituent which the aromatic hydrocarbon group may have may be selected from the following substituent group Z2. Preferred substituents are the preferred substituents in substituent group Z2 described below.

Ar from the viewpoints of solubility and durability of the compound ⁶¹¹ 、Ar ⁶¹² Preferably having at least one partial structure selected from the following formulae (72-1) to (72-7).

[ 39]

In each of the formulas (72-1) to (72-7), at least one of the two groups represents a bond to an adjacent structure or a hydrogen atom, and the bonding position to an adjacent structure is represented. In the following description, the definitions are the same unless otherwise specified.

More preferably Ar ⁶¹¹ 、Ar ⁶¹² At least one of the formulae (72-1) to (72-4) and (72-7).

Further preferably Ar ⁶¹¹ 、Ar ⁶¹² Each having at least one partial structure selected from the group consisting of the formulae (72-1) to (72-3) and (72-7).

Ar is particularly preferred ⁶¹¹ 、Ar ⁶¹² Each having at least one partial structure selected from the group consisting of formula (72-1), formula (72-2) and formula (72-7).

As the formula (72-2), the following formula (72-2-2) is preferable.

[ 40]

As the formula (72-2), the following formula (72-2-3) is more preferable.

[ chemical 41]

In addition, ar is used as Ar from the viewpoints of solubility and durability of the compound ⁶¹¹ 、Ar ⁶¹² The partial structure of at least one of the above is preferably represented by the following formula (72-1) and the partial structure represented by the following formula (72-2).

(R ⁶¹¹ 、R ⁶¹² )

R ⁶¹¹ 、R ⁶¹² Are respectively independentThe monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms which may have a substituent is a halogen atom such as deuterium atom or fluorine atom.

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

Examples of the aromatic hydrocarbon group include monovalent groups of an aromatic hydrocarbon ring having 6 to 30 carbon atoms, more preferably 6 to 18 carbon atoms, and particularly preferably 6 to 10 carbon atoms.

As monovalent aromatic hydrocarbon groups, in particular with Ar ⁶¹¹ The same applies to the aromatic hydrocarbon groups, and phenyl is particularly preferred.

These aromatic hydrocarbon groups may have a substituent. The substituent which the aromatic hydrocarbon group may have is as described above, and specifically, may be selected from the substituent group Z2 described below. Preferred substituents are the preferred substituents in substituent group Z2 described below.

(n ⁶¹¹ 、n ⁶¹² )

n ⁶¹¹ 、n ⁶¹² Each independently is an integer of 0 to 4. n is n ⁶¹¹ 、n ⁶¹² Each independently is preferably 0 to 2, more preferably 0 or 1.

(substituent)

In Ar ⁶¹¹ 、Ar ⁶¹² 、R ⁶¹¹ 、R ⁶¹² In the case of a monovalent or divalent aromatic hydrocarbon group, the substituent which may be present is preferably a substituent selected from the substituent group Z2 described below.

Substituent group Z2 >

Substituent group Z2 is a group including an alkyl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an alkoxycarbonyl group, a dialkylamine group, a diarylamino group, an arylalkylamine group, an acyl group, a halogen atom, a haloalkyl group, an alkylthio group, an arylthio group, a silane group, a siloxane group, a cyano group, an aromatic hydrocarbon group, and an aromatic heterocyclic group. These substituents may also include any of linear, branched, and cyclic structures.

The substituent group Z2 has the following structure.

For example, a linear, branched, or cyclic alkyl group having a carbon number of usually 1 or more, preferably 4 or more and usually 24 or less, preferably 12 or less, more preferably 8 or less, and still more preferably 6 or less, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-hexyl, cyclohexyl, dodecyl;

for example, an alkoxy group having usually 1 to 24 carbon atoms, preferably 12 carbon atoms, such as methoxy group and ethoxy group;

for example, an aryloxy group or a heteroaryloxy group having a carbon number of usually 4 or more, preferably 5 or more and usually 36 or less, preferably 24 or less such as a phenoxy group, a naphthyloxy group or a pyridyloxy group;

an alkoxycarbonyl group having usually 2 or more and usually 24 or less, preferably 12 or less carbon atoms such as a methoxycarbonyl group and an ethoxycarbonyl group;

for example, a dialkylamino group having a carbon number of usually 2 or more and usually 24 or less, preferably 12 or less, such as a dimethylamino group and a diethylamino group;

for example, a diarylamino group having a carbon number of usually 10 or more, preferably 12 or more and usually 36 or less, preferably 24 or less, such as a diphenylamino group and a xylylamino group;

An arylalkyl group having usually 7 carbon atoms and usually 36 or less, preferably 24 or less, such as a phenylmethylamino group;

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

halogen atoms such as fluorine atom and chlorine atom;

haloalkyl groups having usually 1 to 12 carbon atoms, preferably 6 carbon atoms, such as trifluoromethyl;

alkylthio groups having usually 1 to 24 carbon atoms, preferably 12 carbon atoms, such as methylthio and ethylthio;

for example, an arylthio group having usually 4 or more, preferably 5 or more and usually 36 or less, preferably 24 or less carbon atoms such as a phenylthio group, a naphthylthio group and a pyridylthio group;

for example, a silyl group having a carbon number of usually 2 or more, preferably 3 or more and usually 36 or less, preferably 24 or less, such as a trimethylsilyl group and a triphenylsilyl group;

for example, a siloxy group having usually 2 or more carbon atoms, preferably 3 or more carbon atoms and usually 36 or less carbon atoms, preferably 24 or less carbon atoms such as trimethylsiloxy group and triphenylsiloxy group;

cyano group;

for example, an aromatic hydrocarbon group having a carbon number of usually 6 or more and usually 36 or less, preferably 24 or less such as a phenyl group or a naphthyl group;

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

The substituent group Z2 is preferably an alkyl group, an alkoxy group, a diarylamino group, an aromatic hydrocarbon group, or an aromatic heterocyclic group. From the viewpoint of charge transport property, the substituent is preferably an aromatic hydrocarbon group or an aromatic heterocyclic group, more preferably an aromatic hydrocarbon group, and further preferably has no substituent. From the viewpoint of improving solubility, an alkyl group or an alkoxy group is preferable as a substituent.

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

(G)

The number of carbon atoms of the aromatic hydrocarbon group in G is usually 6 to 50, preferably 6 to 30, more preferably 6 to 18. Specific examples of the aromatic hydrocarbon group include benzene ring, naphthalene ring, anthracene ring, tetralin ring, phenanthrene ring,A divalent group having an aromatic hydrocarbon structure in which a carbon number of a ring, a pyrene ring, a benzanthracene ring, a perylene ring or the like is usually 6 or more and usually 30 or less, preferably 18 or less, more preferably 14 or less, or a divalent group having a structure in which a plurality of structures selected from these structures are bonded in a chain or branched manner. When a plurality of aromatic hydrocarbon rings are linked, a structure in which two to eight are linked is usually used, and a structure in which two to five are linked is preferable. When a plurality of aromatic hydrocarbon rings are linked, the same structure may be linked, or different structures may be linked.

G is preferably

A single bond,

Phenylene group,

A divalent group in which a plurality of benzene rings are bonded in a chain or branched manner,

divalent groups in which one or more benzene rings and at least one phenanthrene ring are bonded in a chain or branched manner, or

One or more benzene rings and at least one tetra-extended benzene ring are bonded in a chain or branched manner,

more preferably, the divalent group is a divalent group in which a plurality of benzene rings are bonded in a chain or branched manner. In either case, the order of bonding is not problematic.

The number of benzene rings, naphthalene rings, phenanthrene rings and tetra-extended benzene rings bonded is usually 2 to 8, preferably 2 to 5, as described above. Among them, a divalent group having one to four benzene rings and a naphthalene ring, a divalent group having one to four benzene rings and a phenanthrene ring, or a divalent group having one to four benzene rings and a tetralin ring is more preferable.

These aromatic hydrocarbon groups may have a substituent. The substituents which the aromatic hydrocarbon groups may have may be selected from the substituent group Z2. Preferred substituents are the preferred substituents in the substituent group Z2.

(molecular weight)

The compound represented by the formula (240) is a low molecular material, and the molecular weight thereof 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 is usually 300 or more, preferably 350 or more, more preferably 400 or more.

(specific examples of the compounds represented by the formula (240))

Preferred specific examples of the compound represented by the formula (240) are shown below, but the present invention is not limited to these.

[ chemical 42]

In the composition of the present invention, the compound represented by the formula (240) may be contained in one kind or two or more kinds.

Compounds represented by the formula (260)

[ chemical 43]

(in the formula (260), ar ²¹ ～Ar ³⁵ Each independently represents a hydrogen atom, a phenyl group which may have a substituent, or a monovalent group in which 2 to 10 phenyl groups which may have substituents are linked in an unbranched or branched manner. )

Ar in formula (260) ²¹ ～Ar ³⁵ When the phenyl group which may have a substituent or 2 to 10 phenyl groups which may have substituents are linked in an unbranched or branched manner, the substituent which may be provided by the phenyl group is preferably an alkyl group.

(alkyl group as substituent)

The alkyl group as a substituent is a linear, branched, or cyclic alkyl group having usually 1 to 12 carbon atoms, preferably 8 or less, more preferably 6 or less, and still more preferably 4 or less. Specifically, there may be mentioned: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-hexyl, cyclohexyl, 2-ethylhexyl.

In the formula (260), ar ²¹ 、Ar ²⁵ 、Ar ²⁶ 、Ar ³⁰ 、Ar ³¹ Ar and Ar ³⁵ Preferably a hydrogen atom. In addition, ar is preferably ²² ～Ar ²⁴ At least one of the groups is a phenyl group which can have the substituent or a monovalent group formed by linking 2 to 10 phenyl groups which can have the substituent in an unbranched or branched chain manner, and/or Ar ²² ～Ar ²⁴ At least one of (2), ar ²⁷ ～Ar ²⁹ At least one of the groups (a) is a monovalent group in which a phenyl group which may have the substituent or 2 to 10 phenyl groups which may have the substituent are linked in an unbranched or branched manner.

More preferably Ar ²² ～Ar ²⁴ 、Ar ²⁷ ～Ar ²⁹ Ar, ar ³² ～Ar ³⁴ Is a hydrogen atom, a phenyl group, or any one of structures selected from the following formulae (261-1) to (261-9).

These structures may have the substituent, for example, may be substituted with an alkyl group as the substituent. From the viewpoint of improving solubility, alkyl substitution is preferable. From the viewpoints of charge transport property and durability at the time of element driving, it is preferable that the compound has no substituent.

[ 44]

The compound represented by the formula (260) has such a structure, and thus it is considered that the charge transport property in the light-emitting layer can be appropriately controlled, and the light-emitting efficiency can be improved. In addition, by including such a structure, it is considered that the solubility and durability at the time of element driving are excellent.

(molecular weight)

The compound represented by the formula (260) is a low molecular material, and the molecular weight thereof 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 is usually 300 or more, preferably 350 or more, more preferably 400 or more.

(specific example of the compound represented by the formula (260))

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

[ 45]

[ chemical 46]

In the composition of the present invention, the compound represented by the formula (260) may be contained in one kind or two or more kinds.

[ other Components ]

The composition of the present invention may contain various other solvents as required in addition to the organic solvent and the light-emitting material. Examples of such other solvents include: amides such as N, N-dimethylformamide and N, N-dimethylacetamide, and dimethylsulfoxide.

The compositions of the present invention may also contain various additives such as leveling agents or defoamers.

When two or more layers are laminated by a wet film forming method, the composition of the present invention may contain a photocurable resin or a thermosetting resin for the purpose of preventing the layers from being dissolved and being cured but not dissolved after film formation.

[ proportion of the mixture ]

The concentration of the solid content in the composition of the present invention (the concentration of all solid content including the compound of the present invention, the light-emitting material, the host material other than the compound of the present invention, and optionally components (leveling agent, etc.) and the like) is usually 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.1% by mass or more, still more preferably 0.5% by mass or more, most preferably 1% by mass or more, and generally 80% by mass or less, preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less, and most preferably 20% by mass or less.

When the solid content concentration is in this range, it is preferable that a thin film having a desired film thickness is easily formed in a uniform thickness.

The preferable formulation ratio of the compound of the present invention and the light-emitting material to all host materials contained in the composition of the present invention, that is, the preferable formulation ratio of the compound of the present invention and the light-emitting material to all host materials contained in a light-emitting layer formed using the composition of the present invention (hereinafter, may be referred to as "light-emitting layer of the present invention") is as follows. The term "all host materials" means all host materials other than the compound of the present invention.

The mass ratio of the compound of the present invention to the total mass 100 of the host material in the composition of the present invention and the light-emitting layer of the present invention is usually 5 or more, preferably 10 or more, more preferably 15 or more, and is usually 99 or less, preferably 95 or less, more preferably 90 or less, further preferably 80 or less, and particularly preferably 70 or less.

The molar ratio of the compound of the present invention to the entire host material in the composition of the present invention and the light-emitting layer of the present invention is usually 5 mol% or more, preferably 10 mol% or more, more preferably 20 mol% or more, further preferably 25 mol% or more, particularly preferably 30 mol% or more, and is usually 90 mol% or less, preferably 80 mol% or less, more preferably 70 mol% or less, particularly preferably 60 mol% or less.

The mass ratio of the light-emitting material in the composition of the present invention and the light-emitting layer of the present invention is usually 0.1 or more, preferably 0.5 or more, more preferably 1 or more, particularly preferably 2 or more, and is usually 100 or less, preferably 60 or less, more preferably 50 or less, particularly preferably 40 or less, relative to the mass 100 of the entire host material. If the ratio is below the lower limit or exceeds the upper limit, the luminous efficiency may be significantly reduced.

[ method for producing composition ]

The composition of the present invention is prepared by dissolving a solute comprising the compound of the present invention, the luminescent material and a host material other than the compound of the present invention, if necessary, and various additive components such as a leveling agent or an antifoaming agent, if necessary, in the appropriate organic solvent.

In order to shorten the time required for this dissolution step, and to maintain the concentration of the solute in the composition of the present invention uniform, the solute is usually dissolved while stirring the liquid. The dissolution step may be performed at normal temperature, but may be performed by heating to dissolve the material even when the dissolution rate is low. After the dissolution step is completed, a filtration step such as filtration may be performed as needed.

[ Properties and Properties of the composition ]

< moisture concentration >)

In the case of producing an organic electroluminescent element by forming a layer by a wet film formation method using the composition of the present invention, if moisture is present in the composition, the moisture may be mixed into the formed film, and uniformity of the film may be impaired. Therefore, the moisture content in the composition of the present invention is preferably as small as possible. In addition, in general, since a material such as a cathode which is significantly degraded by moisture is often used in an organic electroluminescent element, it is considered that moisture remains in a film after drying when moisture is present in a composition, and the characteristics of the element may be lowered, which is not preferable.

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

As a method for measuring the concentration of water in the composition, the method described in Japanese Industrial Standard "method for measuring moisture of chemical" (Japanese Industrial Standard (Japanese Industrial Standards, JIS) K0068:2001) is preferable. For example, the analysis can be performed by the Karl Fischer's reagent method (JIS K0211-1348) or the like.

Uniformity >, uniformity

In order to improve the stability in the wet film forming process, for example, the ejection stability from the nozzle in the inkjet film forming method, the composition of the present invention is preferably in a uniform liquid state at ordinary temperature. The term "liquid state uniform at room temperature" means that the composition is a liquid containing a uniform phase and the composition does not contain a particle component having a particle diameter of 0.1 μm or more.

< Properties >

When the viscosity of the composition of the present invention is extremely low, for example, uneven coating due to excessive liquid film flow in the film formation step, poor ejection from the nozzles in inkjet film formation, and the like are liable to occur. When the viscosity of the composition of the present invention is extremely high, clogging of nozzles and the like in inkjet film formation are likely to occur.

Therefore, the viscosity of the composition of the present invention at 25℃is usually 2 mPas or more, preferably 3 mPas or more, more preferably 5 mPas or more, and is usually 1000 mPas or less, preferably 100 mPas or less, more preferably 50 mPas or less.

When the surface tension of the composition of the present invention is high, the following problems may occur: the wettability to the substrate is lowered, leveling property of the liquid film is poor, and film formation surface disorder is easily caused at the time of drying.

Thus, the surface tension of the composition of the invention at 20℃is generally less than 50mN/m, preferably less than 40mN/m.

When the composition of the present invention has a high vapor pressure, there are cases where problems such as a change in solute concentration due to evaporation of the organic solvent are likely to occur.

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

[ method of Forming thin film ]

The film forming method using the composition of the present invention in the film forming method of the present invention is a wet film forming method.

The wet film forming method is a method of forming a liquid film by applying a composition, drying the film, and removing an organic solvent to form a film. In the case where the composition of the present invention contains a light-emitting material, a light-emitting layer can be formed by this method.

The method comprises the following steps: for example, a film formation method by wet deposition using spin coating, dip coating, die coating, bar coating, blade coating, roll coating, spray coating, capillary coating, ink jet, nozzle printing, screen printing, gravure printing, flexographic printing, or the like is used as a coating method, and the coated film is dried to form a film. Among these film forming methods, spin coating, spray coating, inkjet method, nozzle printing method, and the like are preferable.

In the case of manufacturing an organic EL display device including an organic electroluminescent element, an inkjet method or a nozzle printing method is preferable, and an inkjet method is particularly preferable.

The drying method is not particularly limited, and natural drying, reduced pressure drying, heat drying, or reduced pressure drying while heating may be suitably used. In order to further remove the residual organic solvent, heat drying may be performed after natural drying or drying under reduced pressure.

In the drying under reduced pressure, the pressure is preferably reduced to a vapor pressure of the organic solvent contained in the composition of the present invention or lower.

In the case of performing the heat drying, the heating method is not particularly limited, and heating by a heating plate, heating in an oven, infrared heating, or the like may be used.

The heating temperature is usually 80℃or higher, preferably 100℃or higher, more preferably 110℃or higher, and preferably 200℃or lower, more preferably 150℃or lower.

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

As described later, in the organic electroluminescent element, an electron transport layer is formed on the light emitting layer. In the present invention, it is preferable to form a light-emitting layer by a wet film formation method using the composition of the present invention, and to form a layer such as an electron transport layer by a wet film formation method in contact with the light-emitting layer.

The composition for forming an electron transport layer, which is used when an electron transport layer is formed by a wet film forming method in contact with a light-emitting layer, contains at least an electron transport material and an organic solvent. The organic solvent of the composition for forming an electron transport layer is preferably an alcohol-based solvent (a solvent having an alcoholic hydroxyl group) in terms of the difficulty of the compound of the present invention and the excellent solvent resistance. The electron-transporting material of the composition for forming an electron-transporting layer is preferably an electron-transporting compound that is soluble in such an alcohol solvent.

The alcohol-based solvent is preferably an aliphatic alcohol having 3 or more carbon atoms.

In terms of easy dissolution of the electron-transporting material and easy formation of a flat film, an aliphatic alcohol having 6 or more carbon atoms is more preferable.

The aliphatic alcohols preferred as the alcohol-based solvents include: 1-butanol, isobutanol, 2-hexanol, 1-heptanol, 2-methyl-2-pentanol, 4-methyl-3-heptanol, 3-methyl-2-pentanol, 4-methyl-1-pentanol, 4-heptanol, 1-methoxy-2-propanol, 3-methyl-1-pentanol, 4-octanol, 3- (methylamino) -1-propanol, and the like. These alcohol solvents may be used in combination of two or more.

When the electron transport layer is formed by a wet film formation method, the wet film formation method is preferably used.

[ organic electroluminescent element ]

Fig. 1 shows a schematic view (cross section) of an example of the structure of an organic electroluminescent element 8 as an example of the structure of the organic electroluminescent element of the present invention. In fig. 1, 1 denotes a substrate, 2 denotes an anode, 3 denotes a hole injection layer, 4 denotes a hole transport layer, 5 denotes a light emitting layer, 6 denotes an electron transport layer, and 7 denotes a cathode.

[ substrate ]

The substrate 1 is a support for an organic electroluminescent element, and a plate of quartz or glass, a metal plate or foil, a plastic film or sheet, or the like can be generally used. Among these, a glass plate or a plate of transparent synthetic resin such as polyester, polymethacrylate, polycarbonate, polysulfone, or the like is preferable. In order to prevent deterioration of the organic electroluminescent element due to the external air, the substrate is preferably made of a material having high gas barrier properties. Therefore, in particular, when a material having low gas barrier properties such as a synthetic resin substrate is used, it is preferable to provide a dense silicon oxide film or the like on at least one surface of the substrate to improve the gas barrier properties.

[ Anode ]

The anode 2 is responsible for injecting holes into the layer on the light-emitting layer 5 side.

The anode 2 generally comprises: metals such as aluminum, gold, silver, nickel, palladium, platinum, etc.; metal oxides such as indium and/or tin oxides; halogenated metals such as copper iodide; carbon black, poly (3-methylthiophene), polypyrrole, polyaniline and other conductive polymers.

The anode 2 is usually formed by a dry method such as a sputtering method or a vacuum deposition method. In the case of forming the 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, or the like, the anode may be formed by dispersing in an appropriate binder resin solution and applying the solution to a substrate. In the case of the conductive polymer, the anode may be formed by directly forming a thin film on the substrate by electrolytic polymerization or by coating the conductive polymer on the substrate (applied physical report (appl. Phys. Lett.), volume 60, page 2711, 1992).

The anode 2 is usually of a single-layer structure, but may be suitably made of a laminated structure. In the case where the anode 2 has a laminated structure, different conductive materials may be laminated on the anode of the first layer.

The thickness of the anode 2 may be determined according to the required transparency, material, and the like. In particular, when high transparency is required, the thickness is preferably a thickness at which the transmittance of visible light is 60% or more, and more preferably a thickness at which the transmittance of visible light is 80% or more. In this case, the thickness of the anode 2 is usually 5nm or more, preferably 10nm or more, and usually 1000nm or less, preferably 500nm or less. When transparency is not required, the thickness of the anode 2 may be any thickness depending on the required strength or the like. In this case, the anode 2 may be the same thickness as the substrate.

When forming a film on the surface of the anode 2, it is preferable to perform treatment such as ultraviolet/ozone, oxygen plasma, or argon plasma before forming the film, thereby removing impurities on the anode 2 and adjusting the free potential thereof to improve the hole injection property.

[ hole injection layer ]

The layer responsible for the function of transporting holes from the anode 2 side to the light-emitting layer 5 side is generally referred to as a hole injection transport layer or a hole transport layer. When there are two or more layers responsible for the function of transporting holes from the anode 2 side to the light-emitting layer 5 side, the layer closer to the anode 2 side may be referred to as a hole injection layer 3. In terms of enhancing the function of transporting holes from the anode 2 side to the light-emitting layer 5 side, it is preferable to form the hole injection layer 3. In the case of forming the hole injection layer 3, the hole injection layer 3 is typically formed on the anode 2.

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

The hole injection layer may be formed by vacuum evaporation or by a wet film formation method. In terms of excellent film forming properties, it is preferably formed by a wet film forming method.

A general method for forming the hole injection layer will be described below.

In the organic electroluminescent element of the present invention, the hole injection layer 3 is preferably formed by a wet film forming method using the following composition for forming a hole injection layer.

The composition for forming a hole injection layer generally contains a hole transporting compound for a hole injection layer that forms the hole injection layer 3. In the case of the wet film forming method, the composition for forming a hole injection layer generally further contains an organic solvent. The composition for forming a hole injection layer is preferably one which has high hole transport properties and can transport injected holes efficiently. Therefore, it is preferable that the hole mobility is high, and impurities which are likely to become traps are not easily generated at the time of manufacturing or at the time of use. In addition, it is preferable that the polymer has excellent stability, a small free 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 that light emission from the light-emitting layer is not quenched or an excitation complex (exciplex) is formed with the light-emitting layer, so that the light-emitting efficiency is not lowered.

As the hole-transporting compound for the hole injection layer, a compound having a free potential of 4.5eV to 6.0eV is preferable from the viewpoint of a charge injection barrier from the anode to the hole injection layer. Examples of such hole-transporting compounds include: aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzyl phenyl compounds, compounds obtained by linking tertiary amines with fluorenyl groups, hydrazone compounds, silazane compounds, quinacridone compounds, and the like.

Among the above-mentioned exemplary compounds, aromatic amine compounds are preferable in terms of amorphousness and visible light transmittance, and aromatic tertiary amine compounds are particularly preferable. Here, the aromatic tertiary amine compound also includes a compound having an aromatic tertiary amine structure, that is, a compound having a group derived from an aromatic tertiary amine.

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

When the hole injection layer 3 is formed by a wet film forming method, a composition for film formation (composition for hole injection layer formation) is generally prepared by mixing a material for forming the hole injection layer 3 with an organic solvent (solvent for hole injection layer) that can dissolve the material for forming the hole injection layer 3. The hole injection layer 3 is formed by applying the composition for forming a hole injection layer to a layer (typically, the anode 2) corresponding to the lower layer of the hole injection layer 3, and drying the film.

The concentration of the hole-transporting compound in the composition for forming a hole injection layer is arbitrary as long as the effect of the present invention is not significantly impaired, and is preferably low in terms of uniformity of film thickness, and is preferably high in terms of difficulty in occurrence of defects in the hole injection layer 3. Specifically, the content is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, particularly preferably 0.5% by mass or more, and on the other hand, preferably 70% by mass or less, more preferably 60% by mass or less, particularly preferably 50% by mass or less.

Examples of the organic solvent include an ether solvent, an ester solvent, an aromatic hydrocarbon solvent, and an amide solvent.

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

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 the aromatic hydrocarbon solvent include: toluene, xylene, cyclohexylbenzene, 3-isopropylbiphenyl, 1,2,3, 4-tetramethylbenzene, 1, 4-diisopropylbenzene, cyclohexylbenzene, methylnaphthalene, and the like.

Examples of the amide solvent include N, N-dimethylformamide and N, N-dimethylacetamide.

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

The formation of the hole injection layer 3 by the wet film formation method is usually performed by preparing a composition for forming a hole injection layer, then coating the composition on a layer (typically, the anode 2) corresponding to the lower layer of the hole injection layer 3, and drying the layer.

The hole injection layer 3 is usually formed by drying a coating film by heating or drying under reduced pressure after the film formation.

When the hole injection layer 3 is formed by the vacuum vapor deposition method, one or more of the constituent materials of the hole injection layer 3 are usually placed in a crucible provided in a vacuum vessel (in the case of using two or more materials, they are usually placed in different crucibles), and the inside of the vacuum vessel is evacuated to 10 by a vacuum pump ^-4 About Pa. Thereafter, the crucible is heated (in the case of using two or more materials, the respective crucibles are heated in general), and the evaporation amount of the materials in the crucible is controlled while being evaporated (in the case of using two or more materials, the respective materials are usually independent of each otherWhile controlling the amount of evaporation, and evaporating it), a hole injection layer 3 is formed on the anode 2 on the substrate 1 placed facing the crucible. When two or more materials are used, the hole injection layer 3 may be formed by placing a mixture of these materials in a crucible and heating the mixture to evaporate the mixture.

The vacuum degree at the time of vapor deposition is not limited as long as the effect of the present invention is not significantly impaired, and is usually 0.1X10 ^- ⁶ Torr(0.13×10 ^-4 Pa) or more and 9.0X10 ^-6 Torr(12.0×10 ^-4 Pa) is below. The vapor deposition rate is not limited as long as the effect of the present invention is not significantly impaired, and is usually Per second and->And/or less. The film formation temperature at the time of vapor deposition is not limited as long as the effect of the present invention is not significantly impaired, and is preferably 10℃to 50 ℃.

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

[ hole transport layer ]

The hole transport layer 4 is a layer responsible for the function of transporting holes from the anode 2 side to the light emitting layer 5 side. The hole transport layer 4 is not an essential layer for the organic electroluminescent element of the present invention, but is preferably formed in terms of enhancing the function of transporting holes from the anode 2 to the light-emitting layer 5. In the case of forming the hole transport layer 4, the hole transport layer 4 is generally formed between the anode 2 and the light-emitting layer 5. In the presence of the hole injection layer 3, a hole transport layer 4 is formed between the hole injection layer 3 and the light emitting layer 5.

As a material for forming the hole transport layer 4, a material having high hole transport property and capable of efficiently transporting injected holes is preferable. Therefore, it is preferable that the free potential is small, the transparency is high with respect to light of visible light, the hole mobility is large, the stability is excellent, and impurities which become traps are not easily generated at the time of manufacture or use. In addition, since the hole transport layer 4 is in contact with the light emitting layer 5 in many cases, it is preferable that the efficiency be reduced without extinction of light emitted from the light emitting layer 5 or formation of an excitation complex between the light emitting layer 5.

The material of the hole transport layer 4 may be any material that has been used as a constituent material of a hole transport layer, and examples thereof include a hole transport compound used for the hole injection layer 3. In addition, there may be mentioned: arylamine derivatives, fluorene derivatives, spiro derivatives, carbazole derivatives, pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, phthalocyanine derivatives, porphyrin derivatives, silole (silole) derivatives, oligothiophene derivatives, condensed polycyclic aromatic derivatives, metal complexes, and the like.

Examples of the material of the hole transport layer 4 include: polyvinylcarbazole derivatives, polyarylamine derivatives, polyvinyltriphenylamine derivatives, polyfluorene derivatives, polyarylene ether sulfone derivatives containing tetraphenylbenzidine, polyarylene vinylene derivatives, polysiloxane derivatives, polythiophene derivatives, poly (p-phenylacetylene) derivatives, and the like. These may be any of alternating copolymers, random polymers, block polymers, or graft copolymers. In addition, a polymer having branches in the main chain and three or more terminal portions, or a so-called dendrimer (dendrimer) may be used.

Among them, a polyarylene amine derivative or polyarylene derivative is preferable.

The polyarylamine derivative is preferably a polymer comprising a repeating unit represented by the following formula (II). Particularly preferred is a polymer composed of repeating units represented by the following formula (II), in which case Ar in each repeating unit ^a Or Ar ^b May be different.

[ 47]

(in the formula (II), ar ^a Ar and Ar ^b Each independently represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. )

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

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

[ 48]

(in the formula (III-1), R ^a 、R ^b 、R ^c R is R ^d Each independently represents an alkyl group, an alkoxy group, a phenylalkyl group, a phenylalkoxy group, a phenyl group, a phenoxy group, an alkylphenyl group, an alkoxyphenyl group, an alkylcarbonyl group, an alkoxycarbonyl group or a carboxyl group. t and s each independently represent an integer of 0 to 3. In the case where t or s is 2 or more, a plurality of R contained in one molecule ^a Or R is ^b R, which may be identical or different, are contiguous ^a Or R is ^b May form a ring with each other. )

[ 49]

(in the formula (III-2), R ^e R is R ^f R in the formula (III-1) independently of each other ^a 、R ^b 、R ^c Or R is ^d Are the same meaning. r and u each independently represent an integer of 0 to 3. When R or u is 2 or more, a plurality of R's contained in one molecule ^e R is R ^f R, which may be identical or different, are contiguous ^e Or R is ^f May form a ring with each other. X represents an atom or group of atoms constituting a 5-or 6-membered ring. )

Specific examples of X include an oxygen atom, a boron atom which may have a substituent, a nitrogen atom which may have a substituent, a silicon atom which may have a substituent, a phosphorus atom which may have a substituent, a sulfur atom which may have a substituent, a carbon atom which may have a substituent, and a group formed by bonding these.

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

[ 50]

(in the formula (III-3), ar ^c ～Ar ⁱ Each independently represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. V and w each independently represent 0 or 1. )

Specific examples of the above-mentioned formulae (III-1) to (III-3) and specific examples of the polyarylene derivative include those described in Japanese patent application laid-open No. 2008-98619.

In the case of forming the hole transport layer 4 by the wet film formation method, the hole transport layer forming composition is prepared in the same manner as the formation of the hole injection layer 3, and then the film is formed by wet film formation and then heated and dried.

The composition for forming a hole transport layer contains an organic solvent in addition to the hole transport compound. The organic solvent used is the same as that used in the composition for forming a hole injection layer. The film formation conditions, the heat drying conditions, and the like are the same as those in the case of forming the hole injection layer 3.

In the case of forming the hole transport layer 4 by the vacuum deposition method, the film formation conditions and the like are the same as those 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 property improvers, and the like, in addition to the hole transport compounds. Therefore, the hole transport layer-forming composition may contain various light-emitting materials, electron transport compounds, binder resins, coating property improvers, and the like, in addition to the hole transport compounds.

The hole transport layer 4 may be a layer formed by crosslinking a crosslinkable compound. The crosslinkable compound is a compound having a crosslinkable group, and is crosslinked to form a network polymer compound.

Examples of the crosslinkable group include groups derived from cyclic ethers such as oxetane and epoxy; a group derived from an unsaturated double bond such as a vinyl group, a trifluoroethyl group, a styryl group, an acrylic group, a methacryloyl group, a cinnamoyl group, or the like; radicals derived from benzocyclobutene, and the like.

The crosslinkable compound may be any of a monomer, an oligomer, and a polymer. The crosslinkable compound may be used alone, or two or more thereof may be used in any combination and ratio.

As the crosslinkable compound, a hole transporting compound having a crosslinkable group is preferably used.

Examples of the hole-transporting compound as the hole-transporting compound having a crosslinkable group include those exemplified above, and examples of the crosslinkable compound include those in which a crosslinkable group is bonded to a main chain or a side chain relative to these hole-transporting compounds. Particularly preferably, the crosslinkable group is bonded to the main chain via a linking group such as an alkylene group. In addition, the hole-transporting compound is preferably a polymer containing a repeating unit having a crosslinkable group, and more preferably a polymer having a repeating unit in which a crosslinkable group is bonded to a repeating unit represented by the above formula (II) or the formulae (III-1) to (III-3) directly or via a linking group.

When the hole transport layer 4 is formed by crosslinking a crosslinkable compound, a composition for forming a hole transport layer is generally prepared by dissolving or dispersing a crosslinkable compound in an organic solvent, and then film formation and crosslinking are performed by a wet film formation method.

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

[ light-emitting layer ]

The light-emitting layer 5 is a layer responsible for the function of emitting light by being excited by recombination of holes injected from the anode 2 and electrons injected from the cathode 7 when an electric field is applied between the pair of electrodes.

The light-emitting layer 5 is a layer formed between the anode 2 and the cathode 7. In the case where the hole injection layer 3 is present on the anode 2, the light-emitting layer 5 is formed between the hole injection layer 3 and the cathode 7. In the case where the hole transport layer 4 is present on the anode 2, the light-emitting layer 5 is formed between the hole transport layer 4 and the cathode 7.

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

As described above, the light-emitting layer 5 of the organic electroluminescent element of the present invention is formed by the composition of the present invention by a wet film forming method, and preferably contains the compound of the present invention and a light-emitting material.

The thickness of the light-emitting layer 5 is arbitrary as long as the effect of the present invention is not significantly impaired, but is preferably thick in terms of difficulty in occurrence of defects in the film, and is preferably thin in terms of easiness in formation of a low driving voltage.

The film thickness of the light-emitting layer 5 is preferably 3nm or more, more preferably 5nm or more, and on the other hand, preferably 200nm or less, more preferably 100nm or less.

[ hole blocking layer ]

A hole blocking layer may be provided between the light emitting layer 5 and an electron transport layer 6 described below. The hole blocking layer is a layer laminated on the light emitting layer 5 so as to contact the interface on the cathode 7 side of the light emitting layer 5.

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

Examples of the material of the hole blocking layer satisfying such a condition include: mixed ligand complexes such as bis (2-methyl-8-hydroxyquinoline) (phenol) aluminum, bis (2-methyl-8-hydroxyquinoline) (triphenylsilanol) aluminum, metal complexes such as bis (2-methyl-8-hydroxyquinoline) aluminum-mu-oxo-bis- (2-methyl-8-hydroxyquinoline) aluminum dinuclear metal complexes, styryl compounds such as distyryl biphenyl derivatives (JP-A-11-242996), triazole derivatives such as 3- (4-biphenyl) -4-phenyl-5- (4-tert-butylphenyl) -1,2, 4-triazole (JP-A-7-41759), phenanthroline derivatives such as bathocuproin (JP-A-10-79297), and the like. Further, a compound having at least one pyridine ring substituted at the 2,4,6 position described in International publication No. 2005/022962 is also preferable as a material for the hole blocking layer.

The method of forming the hole blocking layer is not limited. Therefore, the film can be formed by a wet film forming method, a vapor deposition method, or other methods.

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

[ Electron transport layer ]

In order to further improve the current efficiency of the element, an electron transport layer 6 is provided between the light emitting layer 5 and the cathode 7.

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

The electron-transporting compound used in the electron-transporting layer 6 is specifically exemplified by: metal complexes such as aluminum complexes of 8-hydroxyquinoline (Japanese patent application laid-open No. 59-194393), metal complexes of 10-hydroxybenzo [ h ] quinoline, oxadiazole derivatives, distyrylbiphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, tribenzimidazolylbenzene (U.S. Pat. No. 5645948), quinoxaline compounds (Japanese patent application laid-open No. 6-207169), phenanthroline derivatives (Japanese patent application laid-open No. 5-331459), 2-t-butyl-9, 10-N, N' -dicyanoanthraquinone diimine, N-hydrogenated amorphous silicon carbide, N-type zinc sulfide, N-type zinc selenide, and the like.

The electron transport layer 6 is formed by stacking on the hole blocking layer by a wet film forming method or a vacuum deposition method in the same manner as described above. Since the compound of the present invention is excellent in solvent resistance, the electron transport layer 6 can be formed on the light-emitting layer containing the compound of the present invention by a wet film forming method as described above.

As described above, the composition for forming an electron transport layer used in forming an electron transport layer by a wet film forming method in contact with a light emitting layer contains at least an electron transport material and an organic solvent. The organic solvent of the composition for forming an electron transport layer is preferably an alcohol-based solvent (a solvent having an alcoholic hydroxyl group) in terms of the difficulty of the compound of the present invention and the excellent solvent resistance. The electron-transporting material of the composition for forming an electron-transporting layer is preferably an electron-transporting compound that is soluble in such an alcohol solvent.

As described above, the alcohol-based solvent used as the solvent of the composition for forming an electron transport layer is preferably an alkyl alcohol having 6 or more carbon atoms in terms of easy dissolution of the electron transport material and easy formation of a flat film having a moderately high boiling point.

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

[ Electron injection layer ]

In order to efficiently inject electrons injected from the cathode 7 into the electron transport layer 6 or the light emitting layer 5, an electron injection layer may be provided between the electron transport layer 6 and the cathode 7.

In order to efficiently perform electron injection, the material forming the electron injection layer is preferably a metal having a low work function. As examples, alkali metals such as sodium and cesium, alkaline earth metals such as barium and calcium, and the like can be used.

The film thickness of the electron injection layer is usually preferably 0.1nm or more and 5nm or less.

Further, it is preferable that an organic electron-transporting material represented by a nitrogen-containing heterocyclic compound such as bathophenanthroline (bathophenanthroline) or a metal complex such as an aluminum complex of 8-hydroxyquinoline is doped with an alkali metal such as sodium, potassium, cesium, lithium or rubidium (described in JP-A-10-270171, JP-A-2002-100478 or JP-A-2002-100482).

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

The electron injection layer is formed by stacking the light-emitting layer 5 or the hole blocking layer or the electron transport layer 6 thereon by a wet film forming method or a vacuum vapor deposition method.

The details in the wet film formation method are the same as those in the case of the light-emitting layer.

There are also cases where the hole blocking layer, the electron transporting layer, and the electron injecting layer are formed as one layer by an operation of co-doping an electron transporting material with a lithium complex.

[ cathode ]

The cathode 7 functions as a layer (electron injection layer, light emitting layer, or the like) that injects electrons into the light emitting layer 5 side.

As the material of the cathode 7, a material used for the anode 2 can be used. For efficient electron injection, a metal having a low work function is preferably used as the material of the cathode 7, and for example, metals such as tin, magnesium, indium, calcium, aluminum, and silver, or alloys of these metals can be used. Specific examples include: low work function alloy electrodes such as magnesium-silver alloy, magnesium-indium alloy, aluminum-lithium alloy, and the like.

In terms of stability of the organic electroluminescent element, it is preferable to laminate a metal layer having a high work function and stable to the atmosphere on the cathode to protect the cathode containing a metal having a low work function. Examples of the metal to be laminated include: metals such as aluminum, silver, copper, nickel, chromium, gold, platinum, and the like.

The cathode typically has the same film thickness as the anode.

[ other layers ]

The organic electroluminescent element of the present invention may further have other layers as long as the effect of the present invention is not significantly impaired. That is, any of the other layers described above may be provided between the anode and the cathode.

[ other element Structure ]

The organic electroluminescent element of the present invention may have a structure opposite to the above description, that is, for example, a structure in which 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, and an anode are stacked in this order on a substrate is also possible.

When the organic electroluminescent element of the present invention is applied to an organic electroluminescent device, the organic electroluminescent element may be used as a single organic electroluminescent element, and a plurality of organic electroluminescent elements may be arranged in an array, or an anode and a cathode may be arranged in an X-Y matrix.

[ display device ]

The display device of the present invention (organic electroluminescent element display device: organic EL display device) includes the organic electroluminescent element of the present invention. Regarding the model or structure of the organic EL display device of the present invention, there is no particular limitation, and the organic electroluminescent element of the present invention may be used and assembled according to a conventional method.

For example, the organic EL display device of the present invention can be formed by a method described in "organic EL display" (issued by omu corporation (Ohmsha), 8/20/2004, ren Jingshi, adakilowave vector, and village Tian Yingxing).

[ Lighting device ]

The lighting device (organic electroluminescent element lighting device: organic EL lighting device) of the present invention includes the organic electroluminescent element of the present invention. The type or structure of the organic EL lighting device of the present invention is not particularly limited, and the organic electroluminescent element of the present invention may be used and assembled according to a conventional method.

Examples (example)

Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to the following examples unless the gist thereof is exceeded.

The values of the various conditions or evaluation results in the following examples have meanings as preferable values of the upper limit or the lower limit in the embodiment of the present invention, and preferable ranges may be ranges defined by combinations of the values of the upper limit or the lower limit and the values of the following examples or the values of the examples each other.

In the present specification, ac means acetyl, ph means phenyl, dppf means 1,1' -bis (diphenylphosphino) ferrocene, DMSO means dimethyl sulfoxide, bu means butyl, and THF means tetrahydrofuran.

In the following examples and comparative examples, the following compounds 1 to 3 and comparative compounds 1 to 6 were evaluated.

Compound C1-a and comparative compound 3 were synthesized according to the method described in international publication No. 2012/096263.

Compound C2-a, compound C5-a and comparative compound 6 were synthesized according to the methods described in international publication No. 2012/137958.

[ 51]

[ Synthesis and evaluation of Compounds ]

Example I-1: synthesis of Compound 1] < Synthesis of Compound 1-b >)

[ 52]

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

< Synthesis of Compounds 1-d >

[ 53]

To compound 1-b (4.7 g,10.3 mmol) and compound 1-c (4.5 g,10.3 mmol) were successively added THF (100 mL) subjected to nitrogen bubbling, and an aqueous tripotassium phosphate solution (2.0 mol/L,13 mL) under a nitrogen atmosphere. After that, pd (PPh) ₃ ) ₄ (0.12 g,0.10 mmol) was heated and stirred at 55℃for 8 hours. After cooling to room temperature, a saturated aqueous sodium chloride solution and 1N diluted hydrochloric acid were added, and extraction was performed using dichloromethane. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and then distilled under reduced pressure to remove the solvent. The residue was subjected to silica gel column chromatography to obtain compound 1-d (yield 4.9g, yield 66%).

< Synthesis of Compound 1 >

[ 54]

To compound 1-d (2.2 g,3.04 mmol) and compound 1-e (1.3 g,4.56 mmol) were successively added THF (30 mL) subjected to nitrogen bubbling, and an aqueous tripotassium phosphate solution (2.0 mol/L,5 mL) under nitrogen atmosphere. After that, pd (PPh) ₃ ) ₄ (35 mg,0.030 mmol) was stirred with heating at 70℃for 2 hours. After cooling to room temperature, a saturated aqueous sodium chloride solution and 1N diluted hydrochloric acid were added, and extraction was performed using dichloromethane. Washing with saturated aqueous sodium chloride solutionThe organic layer was dried over magnesium sulfate, and then the solvent was distilled off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain compound 1 (yield 1.9g, yield 67%).

Example I-2: synthesis of Compound 2

< Synthesis of Compound 2-c >

[ 55]

To compound 2-a (11.6 g,40.5 mmol), compound 2-b (14.5 g,40.5 mmol) were successively added toluene (100 mL), ethanol (50 mL), and an aqueous solution of tripotassium phosphate (2.0 mol/L,50 mL) subjected to nitrogen bubbling, and heated to 50 ℃. Thereafter, pdCl is added ₂ (PPh ₃ ) ₂ (0.29 g,0.41 mmol) was stirred at 65℃for 3 hours. After cooling to room temperature, a saturated aqueous sodium chloride solution was added, and extraction was performed using toluene. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and then distilled under reduced pressure to remove the solvent. The residue was subjected to silica gel column chromatography to obtain compound 2-c (yield 15.7g, yield 82%).

< Synthesis of Compound 2-d >

[ 56]

To compound 2-c (11.6 g,24.5 mmol), bis (pinacolato diboron) (9.3 g,36.7 mmol), potassium acetate (7.2 g,73.5 mmol) was added dehydrated DMSO (100 mL) and heated to 50 ℃. Adding PdCl ₂ (dppf)CH ₂ Cl ₂ (1.0 g,1.2 mmol) was stirred at 90℃for 8 hours. After cooling to room temperature, distilled water was added, and suction filtration was performed. The filtrate was dissolved in toluene, washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and distilled under reduced pressure to remove the solvent. The residue was subjected to silica gel column chromatography to obtain compound 2-d (yield 8.0g, yield 63%).

< Synthesis of Compound 2 >

[ 57]

To compound 1-d (1.4 g,1.97 mmol) and compound 2-d (1.1 g,2.17 mmol) were added THF (30 mL) subjected to nitrogen bubbling, followed by aqueous tripotassium phosphate (2.0 mol/L,3 mL) under nitrogen atmosphere. After that, pd (PPh) ₃ ) ₄ (23 mg, 0.020mmol) was heated and stirred at 70℃for 3 hours. After cooling to room temperature, a saturated aqueous sodium chloride solution and 1N diluted hydrochloric acid were added, and extraction was performed using dichloromethane. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and then distilled under reduced pressure to remove the solvent. The residue was subjected to silica gel column chromatography to obtain compound 2 (yield 2.0g, yield 93%).

Example I-3: synthesis of Compound 3

< Synthesis of Compound 3-b >

[ 58]

To compound 3-a (26.2 g,68.0 mmol) was added dehydrated THF (150 mL) under nitrogen and cooled to-75 ℃. Thereafter, n-BuLi (1.59 mol/L,43 mL) was added dropwise thereto, and the mixture was stirred at-75℃for 3 hours. The prepared solution was added dropwise to a solution of cyanuric chloride (25.1 g,136.1 mmol) in dehydrated THF (150 mL) cooled to-100 ℃. After warming to room temperature, a saturated aqueous sodium chloride solution and 1N diluted hydrochloric acid were added, and extraction was performed using ethyl acetate. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and then distilled under reduced pressure to remove the solvent. The residue was subjected to silica gel column chromatography to obtain compound 3-b (yield 9.0g, yield 29%).

< Synthesis of Compound 3 >

[ 59]

To compound 3-b (1.3 g,2.88 mmol) and compound 2-d (3.0 g,5.77 mmol) were successively added THF (60 mL) subjected to nitrogen bubbling, and an aqueous tripotassium phosphate solution (2.0 mol/L,20 mL). After that, pd (PPh) ₃ ) ₄ (67 mg,0.58 mmol) was stirred at 70℃for 4 hours. After cooling to room temperature, a saturated aqueous sodium chloride solution and 1N diluted hydrochloric acid were added, and extraction was performed using dichloromethane. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and then distilled under reduced pressure to remove the solvent. The residue was subjected to silica gel column chromatography to obtain compound 3 (yield 2.2g, yield 65%).

Example I-4: synthesis of Compound 4

< Synthesis of Compound 4-c >

[ chemical 60]

To compound 4-a (10 g,14.4 mmol) and compound 4-b (5.2 g,14.4 mmol) were successively added THF (60 mL) subjected to nitrogen bubbling, and an aqueous tripotassium phosphate solution (2.0 mol/L,20 mL). After that, pd (PPh) ₃ ) ₄ (160 mg,0.14 mmol) was stirred at 55℃for 7 hours. After cooling to room temperature, a saturated aqueous sodium chloride solution and 1N diluted hydrochloric acid were added, and extraction was performed using dichloromethane. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and then distilled under reduced pressure to remove the solvent. The residue was subjected to silica gel column chromatography to obtain compound 4-c (yield 6.9g, yield 51%).

< Synthesis of Compound 4 >

[ chemical 61]

To compound 4-c (8.5 g,9.1 mmol), compound 4-d (2.7 g,10 mmol)Toluene (50 mL), ethanol (28 mL), and an aqueous solution of tripotassium phosphate (2.0 mol/L,28 mL) were added in portions. After that, pd (PPh) ₃ ) ₄ (315 mg,0.27 mmol) was stirred at 95℃for 2 hours. After cooling to room temperature, a saturated aqueous sodium chloride solution was added, and extraction was performed using toluene. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and then distilled under reduced pressure to remove the solvent. The residue was subjected to silica gel column chromatography to obtain compound 4 (yield 9.7g, yield 80%).

Comparative example I-1: comparative Synthesis of Compound 1

[ 62]

To compound C1-a (0.89 g,1.53 mmol) and compound C1-b (0.66 g,1.53 mmol) were successively added THF (15 mL) subjected to nitrogen bubbling, and an aqueous tripotassium phosphate solution (2.0 mol/L,5 mL). After that, pd (PPh) ₃ ) ₄ (18 mg,0.015 mmol) and stirred at 70℃for 4 hours. After cooling to room temperature, a saturated aqueous sodium chloride solution and 1N diluted hydrochloric acid were added, and extraction was performed using dichloromethane. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and then distilled under reduced pressure to remove the solvent. The residue was subjected to silica gel column chromatography to obtain comparative compound 1 (yield 0.9g, yield 69%).

Comparative example I-2: comparative Synthesis of Compound 2

[ 63]

To compound C2-a (0.66 g,0.91 mmol) and compound C2-b (0.49 g,1.37 mmol) were added THF (15 mL) subjected to nitrogen bubbling, followed by aqueous tripotassium phosphate (2.0 mol/L,5 mL). After that, pd (PPh) ₃ ) ₄ (11 mg,0.0091 mmol) and stirred at 70℃for 2.5 hours. After cooling to room temperature, saturated aqueous sodium chloride solution and 1N diluted hydrochloric acid are added,and extracted with methylene chloride. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and then distilled under reduced pressure to remove the solvent. The residue was subjected to silica gel column chromatography to obtain comparative compound 2 (yield 0.9g, yield 98%).

Comparative example I-4: comparative Synthesis of Compound 4

[ 64]

To compound C4-a (0.10 g,0.48 mmol), compound 2-d (0.50 g,0.96 mmol) were successively added THF (12 mL) subjected to nitrogen bubbling, and an aqueous tripotassium phosphate solution (2.0 mol/L,4 mL). After that, pd (PPh) ₃ ) ₄ (11 mg,0.0091 mmol) and stirred at 70℃for 6 hours. After cooling to room temperature, a saturated aqueous sodium chloride solution and 1N diluted hydrochloric acid were added, and extraction was performed using dichloromethane. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and then distilled under reduced pressure to remove the solvent. The residue was subjected to silica gel column chromatography to obtain comparative compound 4 (yield 0.3g, yield 67%).

Comparative example I-5: comparative Synthesis of Compound 5

[ 65]

To compound C5-a (1.26 g,3.33 mmol) and compound 2-b (2.42 g,6.66 mmol) were added THF (30 mL) subjected to nitrogen bubbling, followed by aqueous tripotassium phosphate (2.0 mol/L,10 mL). After that, pd (PPh) ₃ ) ₄ (77 mg,0.066 mmol) was stirred at 70℃for 3 hours. After cooling to room temperature, a saturated aqueous sodium chloride solution and 1N diluted hydrochloric acid were added, and extraction was performed using dichloromethane. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and then distilled under reduced pressure to remove the solvent. The residue was subjected to silica gel column chromatography to obtain comparative compound 5 (yield 1.2g, yield 38%))。

[ evaluation of solvent solubility of Compounds 1 to 3 and comparative Compounds 1 to 5]

The solubility of each compound with respect to Cyclohexylbenzene (CHB) was evaluated.

About 1 mL-2 mL of a cyclohexylbenzene solution (concentration of each compound: 2.0 mass% and 6.0 mass%) was prepared, and the solubility of Cyclohexylbenzene (CHB) was determined based on whether each compound was dissolved in the solution.

The results are shown in Table 1.

In the columns "2.0 mass% CHB solution" and "6.0 mass% CHB solution" in table 1, "o" means that the compound was dissolved in the solution, and "×" means that the compound was not dissolved in the solution.

In the column "precipitation test of 6.0 mass% CHB solution" in table 1, "ring" indicates that no compound was precipitated from the solution after 1 day of preparation of the 6.0 mass% CHB solution, and "×" indicates that no compound was precipitated from the solution after 1 day of preparation of the 6.0 mass% CHB solution.

TABLE 1

As is clear from table 1, the compound of the present invention has excellent solvent solubility in both the sense of being rapidly dissolved in an organic solvent and not being precipitated after dissolution and kept in a uniform state.

[ confirmation of solvent resistance of Compounds 1 to 3 and Compound 6 to be compared ]

The solvent resistance of each compound was confirmed as follows.

First, a solution in which a compound to be tested was dissolved in toluene at 1.5 wt% was prepared. The solution was spin-coated on a glass substrate dropwise in a nitrogen glove box, and dried on a hot plate at 100 ℃ for 10 minutes to form a compound film of the test object.

Then, a substrate having a compound film formed thereon was set on a spin coater, 150. Mu.L of 1-butanol was dropped onto the compound film as a test solvent, and the solution was allowed to stand for 60 seconds after the dropping to perform a solvent resistance test.

Thereafter, the substrate was rotated at 1500rpm for 30 seconds, followed by 4000rpm for 30 seconds and the dropped solvent was spun out.

The substrate was dried on a hot plate at 100℃for 10 minutes.

The film thickness of each compound film before and after the solvent resistance test was measured using a stylus type step meter, and the residual film ratio (= (film thickness after test/film thickness before test) ×100) was calculated as the ratio of the film thicknesses before and after the test.

Further, the residual film rate exceeds 100% and is a measurement error.

The results are shown in Table 2.

TABLE 2

	Residual film percentage (%)
		Compound 1	98.1
Compound 2	100.7
		Compound 3	101.1
Comparative Compound 6	90.6

As can be seen from Table 2, the compounds of the present invention exhibited high solvent resistance relative to alcohols.

[ production of organic electroluminescent device and evaluation of Performance ]

Example II-1

An organic electroluminescent device was fabricated by the following method.

An Indium Tin Oxide (ITO) transparent conductive film was deposited on a glass substrate to a thickness of 50nm (manufactured by Ji Aoma technology (Geomatec)), and then patterned into stripes 2mm wide by etching with hydrochloric acid using a general photolithography technique to form an anode. The substrate on which the ITO was patterned in the above manner was washed in the order of ultrasonic washing with an aqueous solution of a surfactant, water washing with ultrapure water, ultrasonic washing with ultrapure water, and water washing with ultrapure water, and then dried with compressed air, and finally subjected to ultraviolet ozone washing.

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

[ chemical 66]

The composition for forming a hole injection layer was spin-coated on the substrate in the atmosphere, and dried at 240℃for 30 minutes using a heating plate in the atmosphere to form a uniform thin film having a film thickness of 40nm, and was used as a hole injection layer.

Next, a charge transporting polymer compound having the following formula (HT-1) was dissolved in 1,3, 5-trimethylbenzene to prepare a 2.0 wt% solution.

The solution was spin-coated on a substrate having the hole injection layer formed thereon in a nitrogen glove box, and dried at 230 ℃ for 30 minutes using a heating plate in the nitrogen glove box, thereby forming a uniform thin film having a film thickness of 40nm, and setting the thin film as a hole transport layer.

[ 67]

Next, as a material of the light-emitting layer, a composition for forming a light-emitting layer was prepared by dissolving in cyclohexylbenzene at a concentration of 2.3 wt% of compound 1, 2.3 wt% of compound (H-1) below, and 1.4 wt% of compound (D-1) below.

[ chemical 68]

The composition for forming a light-emitting layer was spin-coated on a substrate having the hole transport layer formed thereon in a nitrogen glove box, and dried at 120 ℃ for 20 minutes using a heating plate in the nitrogen glove box, thereby forming a uniform thin film having a film thickness of 40nm, and was set as a light-emitting layer.

The substrate formed to the light-emitting layer was set in a vacuum vapor deposition apparatus, and the inside of the apparatus was evacuated to 2×10 ^-4 Pa or less.

Next, the following compound (ET-1) and lithium 8-hydroxyquinoline were prepared as 2:3, and forming an electron transport layer having a film thickness of 30 nm.

[ 69]

Then, as a mask for cathode vapor deposition, a 2mm wide shadow mask (shadow mask) was closely attached to the substrate so as to be perpendicular to the ITO stripes of the anode, and aluminum was heated by a molybdenum boat to form an aluminum layer having a film thickness of 80nm, thereby forming a cathode.

As described above, an organic electroluminescent element having a light emitting area portion with a size of 2mm×2mm was obtained.

Example II-2

An organic electroluminescent device was produced in the same manner as in example 1, except that compound 2 was used instead of compound 1 as a material of the light-emitting layer.

Example II-3

An organic electroluminescent device was produced in the same manner as in example 1, except that compound 3 was used instead of compound 1 as a material of the light-emitting layer.

Comparative example II-4

An organic electroluminescent device was produced in the same manner as in example 1, except that comparative compound 4 was used instead of compound 1 as a material of the light-emitting layer.

[ evaluation of element ]

The organic electroluminescent elements obtained in examples II-1 to II-3 and comparative example II-4 were set at 1,000cd/m ² The voltage (V), current efficiency (cd/A), and external quantum efficiency (%) at the time of light emission were measured. In addition, at 15mA/cm ² When the element was continuously energized, the time (LT 95) from the decrease in luminance to 95% of the initial luminance was measured. The measurement results are shown in Table 3. In Table 3, the voltage difference represents the value (V) obtained by subtracting the value of comparative example II-4 from the voltage of example II-1 to example II-3, and the relative current efficiency, the relative external quantum efficiency, and the relative lifetime represent the relative values of the values of example II-1 to example II-3 when the value of comparative example II-4 is 1.

From the results in table 3, it is apparent that the performance of the organic electroluminescent element using the compound of the present invention is improved.

TABLE 3

Examples II-4

An organic electroluminescent device was produced in the same manner as in example II-1 except that a light-emitting layer was formed as follows.

As a material of the light-emitting layer, a composition for forming a light-emitting layer was prepared by dissolving cyclohexylbenzene at a concentration of 2.7 wt% of compound 4, 2.7 wt% of compound (H-2) described below, and 1.6 wt% of compound (D-1).

[ 70]

The composition for forming a light-emitting layer was spin-coated on a substrate on which the hole transport layer was formed in a nitrogen glove box, and dried at 120 ℃ for 20 minutes using a heating plate in the nitrogen glove box, thereby forming a uniform thin film having a film thickness of 70nm, and setting the thin film as a light-emitting layer.

Examples II-5

An organic electroluminescent device was produced in the same manner as in example II-4, except that compound 3 was used instead of compound 4 as a material of the light-emitting layer.

Comparative example II-5

An organic electroluminescent device was produced in the same manner as in example II-4, except that comparative compound 4 was used instead of compound 4 as a material of the light-emitting layer.

[ evaluation of element ]

The organic electroluminescent elements obtained in example II-4, example II-5 and comparative example II-5 were set at 1,000cd/m ² The voltage (V), current efficiency (cd/A), and external quantum efficiency (%) at the time of light emission were measured. In addition, at 15mA/cm ² When the element is continuously energized, the time (LT 97) from the decrease in luminance to 97% of the initial luminance is measured. The measurement results are shown in Table 4. In Table 4, the voltage difference represents the value (V) obtained by subtracting the value of comparative example II-5 from the voltage of example II-4 or example II-5, and the relative current efficiency, the relative external quantum efficiency, and the relative lifetime represent the relative values of the values of example II-4 and example II-5 when the value of comparative example II-5 is 1.

From the results in table 4, it is apparent that the performance of the organic electroluminescent element using the compound of the present invention is improved.

TABLE 4

The present invention has been described in detail with reference to specific embodiments, but it will be apparent to those skilled in the art that various changes can be made without departing from the spirit and scope of the invention.

The present application is based on Japanese patent applications 2021-094592 filed on 6/4 of 2021 and Japanese patent applications 2021-148728 filed on 13/9 of 2021, which are incorporated by reference in their entirety.

Claims

1. A compound represented by the following formula (1-1) or the following formula (1-2),

in the formula (1-1),

Xa ¹ 、Ya ¹ and Za ¹ Each independently represents a 1, 3-phenylene group with or without a substituent, or a 1, 4-phenylene group with or without a substituent,

Za ¹ at least one of which is a 1, 3-phenylene group,

Xa ² ya ² Each independently represents a phenyl group having or not having a substituent,

Za ² represents an N-carbazolyl group with or without a substituent,

f11 is either 1 or 2,

g11 is an integer of 1 to 5,

h11 is an integer of 2 to 5,

j11 is an integer of 1 to 6,

f11+g11+h11+j11 is 5 or more,

R ¹¹ Each independently represents a hydrogen atom or a substituent;

in the formula (1-2),

Ya ¹ za and Za ¹ At least one of which is a 1, 3-phenylene group with or without a substituent,

Xa ² represents a phenyl group having or not having a substituent,

Ya ² za and Za ² Each independently represents an N-carbazolyl group having or not having a substituent,

f11 is either 1 or 2,

g11 is an integer of 1 to 5,

h11 is an integer of 2 to 5,

j11 is an integer of 2 to 5,

f11+g11+h11+j11 is 6 or more,

R ¹¹ each independently represents a hydrogen atom or a substituent.

2. The compound according to claim 1, wherein Ya in the formula (1-2) ¹ At least one of (a) is 1, 3-phenylene, za ¹ At least one of which is a 1, 3-phenylene group.

3. The compound according to claim 1 or claim 2, wherein Xa in the formula (1-2) ¹ At least one of which is a 1, 3-phenylene group.

4. An organic electroluminescent element having an anode and a cathode on a substrate with an organic layer therebetween, the element comprising the compound according to any one of claims 1 to 3.

5. The organic electroluminescent element according to claim 4, wherein the organic layer comprises a light-emitting layer comprising the compound.

6. A composition comprising at least a compound according to any one of claims 1 to 3 and an organic solvent.

7. The composition according to claim 6, further comprising a light-emitting material, and a charge transport material different from the compound represented by the formula (1-1) and the compound represented by the formula (1-2).

8. The composition according to claim 7, wherein the charge transport material different from the compound represented by the formula (1-1) and the compound represented by the formula (1-2) is a compound represented by the following formula (240) and/or a compound represented by the following formula (260),

in the formula (240), the amino acid sequence of the formula (240),

Ar ⁶¹¹ 、Ar ⁶¹² each independently represents a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms and having or not having a substituent;

R ⁶¹¹ 、R ⁶¹² each independently represents a deuterium atom, a halogen atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms with or without a substituent;

g represents a single bond or a divalent aromatic hydrocarbon group having 6 to 50 carbon atoms with or without a substituent;

n ⁶¹¹ 、n ⁶¹² each independently is an integer of 0 to 4;

Ar in formula (260) ²¹ ～Ar ³⁵ Independently of one another, represent a hydrogen atom, a group of atoms, or a group of atomsPhenyl group having no substituent or monovalent group in which 2 to 10 phenyl groups having or not having a substituent are linked in an unbranched or branched manner.

9. The composition of claim 8, wherein Ar in the formula (240) ⁶¹¹ Ar and Ar ⁶¹² Each independently represents a monovalent group having a plurality of benzene rings bonded in a chain or branched manner, with or without a substituent.

10. The composition of claim 8, wherein R in the formula (240) ⁶¹¹ R is R ⁶¹² Each independently represents a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms and having or not having a substituent.

11. The composition of claim 8, wherein n in the formula (240) ⁶¹¹ N is as follows ⁶¹² Each independently 0 or 1.

12. The composition of claim 8, wherein in the formula (260), ar ²¹ 、Ar ²⁵ 、Ar ²⁶ 、Ar ³⁰ 、Ar ³¹ Ar and Ar ³⁵ Is a hydrogen atom, and is preferably a hydrogen atom,

Ar ²² ～Ar ²⁴ 、Ar ²⁷ ～Ar ²⁹ ar, ar ³² ～Ar ³⁴ Each independently is a hydrogen atom, a phenyl group having or not having a substituent, or any one of structures selected from the following formulae (261-1) to (261-9) having or not having a substituent,

13. a thin film forming method comprising the step of forming a film of the composition according to any one of claims 6 to 12 by a wet film forming method.

14. A method for manufacturing an organic electroluminescent element, wherein an anode and a cathode are provided on a substrate of the organic electroluminescent element, an organic layer is provided between the anode and the cathode,

the method for producing an organic electroluminescent element comprises a step of forming the organic layer by a wet film formation method using the composition according to any one of claims 6 to 12.

15. The method for manufacturing an organic electroluminescent element according to claim 14, wherein the organic layer is a light-emitting layer.

16. A method for manufacturing an organic electroluminescent element, wherein the substrate of the organic electroluminescent element is provided with an anode and a cathode, an organic layer is arranged between the anode and the cathode, the organic layer comprises a light-emitting layer and an electron transport layer,

the method for manufacturing an organic electroluminescent element comprises the following steps: a step of forming the light-emitting layer by a wet film formation method using the composition according to any one of claims 6 to 12; and

17. The method for manufacturing an organic electroluminescent element according to claim 16, wherein the solvent contained in the composition for forming an electron transport layer is an alcohol-based solvent.