CN117441418A

CN117441418A - Aromatic compound and organic electroluminescent element

Info

Publication number: CN117441418A
Application number: CN202280039824.2A
Authority: CN
Inventors: 长谷川司; 冈部一毅; 李延军; 弘大辅
Original assignee: Mitsubishi Chemical Corp
Current assignee: Mitsubishi Chemical Corp
Priority date: 2021-06-04
Filing date: 2022-06-01
Publication date: 2024-01-23

Abstract

An organic electroluminescent element comprising an anode and a cathode on a substrate, wherein an organic layer is provided between the anode and the cathode, and wherein the organic layer comprises a layer containing an aromatic compound represented by the following formula (1).(Ar ¹ ～Ar ⁵ Is a hydrogen atom or an aromatic hydrocarbon group having 6 to 60 carbon atoms. Ar (Ar) ¹ 、Ar ² And Ar is a group ⁵ Is represented by the following formula (2) or formula (3). L (L) ¹ ～L ⁵ An aromatic hydrocarbon group having 6 to 60 carbon atoms. R is a specific substituent. )

Description

Aromatic compound and organic electroluminescent element

Technical Field

The present invention relates to an aromatic compound which can be used for an organic electroluminescent element (hereinafter, sometimes referred to as an "organic light emitting diode (organic light emitting diode, OLED)" or "element"). The present invention also relates to an organic electroluminescent element comprising the aromatic compound, a display device and a lighting device comprising the organic electroluminescent element, 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 continuously, and the development of luminescent colors is also advanced by 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 to influence the life of the element or the reason for improving the power consumption. For example, it is considered that the heat resistance and durability and crystallinity of the material constituting the element have a great influence on the life.

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 material used has poor solubility, it may be degraded before use because of a long-time heating operation or the like. If the solution state cannot be maintained in a uniform state for a long period of time, precipitation of the material from the solution occurs, and film formation by an inkjet device or the like cannot be performed.

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

In order to manufacture an organic electroluminescent element by forming all organic layers by a wet film forming method by multilayer lamination coating of organic layers, solvent resistance to ink applied thereon after wet film forming is required.

Patent document 1 reports an OLED material using an aromatic compound such as the following compound (C-1) or the following compound (C-2) as a charge transport material for a phosphorescent compound.

[ chemical 1]

Patent document 1: international publication No. 2007/043357

Disclosure of Invention

The compound has high solubility and a large band gap, but has a glass transition temperature as low as 99℃in the compound (C-1) and as low as 87℃in the compound (C-2), and thus has insufficient heat resistance. In addition, when a film is laminated on a film formed from the compound by a wet film forming method using an alcohol solvent, the solvent resistance against the alcohol solvent used is insufficient.

Disclosure of Invention

The present invention provides a compound having excellent heat resistance and solvent solubility, excellent solvent resistance to alcohol solvents in a film, and further having a large band gap.

The object of the present invention is to provide an organic electroluminescent element comprising the compound, a display device and a lighting device comprising the organic electroluminescent element, a composition comprising the compound and a solvent, a method for forming a thin film using the composition, and a method for producing an organic electroluminescent element.

[ means for solving the problems ]

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

The gist of the present invention is as follows < 1 > - < 32 >.

< 1 > an organic electroluminescent element having an anode and a cathode on a substrate, an organic layer between the anode and the cathode, wherein, in the organic electroluminescent element,

the organic layer has a layer containing an aromatic compound represented by the following formula (1).

[ chemical 2]

(in the formula (1),

Ar ¹ ～Ar ⁵ each independently represents a hydrogen atom or a monovalent aromatic hydrocarbon group having 6 or more and 60 or less carbon atoms and having or not having a substituent,

Ar ¹ 、Ar ² and Ar is a group ⁵ Is represented by the following formula (2) or the following formula (3).

L ¹ ～L ⁵ Each independently represents a divalent aromatic hydrocarbon group having 6 to 60 carbon atoms which may have a substituent.

R each independently represents an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyl group, a halogen atom, a haloalkyl group, an alkylthio group, an arylthio group, a silyl group, a siloxy group, an aralkyl group or an aromatic hydrocarbon group.

m1, m2 and m5 each independently represent an integer of 0 to 5.

m3 and m4 each independently represent an integer of 1 to 5.

n represents an integer of 0 to 10.

a1 and a2 each independently represent an integer of 0 to 3.

a3 represents an integer of 0 to 4.

a4 represents an integer of 0 or 1.

Where a4 is 0 when a3 is 4.

In Ar ¹ ～Ar ⁵ A substituent which may be contained in a monovalent aromatic hydrocarbon group having 6 or more and 60 or less of a carbon number, and L ¹ ～L ⁵ The substituent which the divalent aromatic hydrocarbon group having 6 to 60 carbon atoms may have is each independently an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyl group, a halogen atom, a haloalkyl group, an alkylthio group, an arylthio group, a silyl group, a siloxy group, an aralkyl group or an aromatic hydrocarbon group.

In the formula (1), ar ¹ -(L ¹ ) _m1 -、Ar ² -(L ² ) _m2 -、Ar ³ -(L ³ ) _m3 -、Ar ⁴ -(L ⁴ ) _m4 None of them are hydrogen atoms. )

[ chemical 3]

(in the formula (2) or (3),

asterisks indicate the bond with formula (1).

R ¹ ～R ²⁶ Each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyl group, a halogen atom, a haloalkyl group, an alkylthio group, an arylthio group, a silyl group, a siloxy group, an aralkyl group, or an aromatic hydrocarbon group. )

< 2 > according to < 1 >The organic electroluminescent element, wherein Ar ¹ And Ar is a group ² Ar when n is 1 or more ⁵ Or at least one Ar when n is 2 or more ⁵ Represented by the formula (2) or the formula (3).

< 3 > the organic electroluminescent element according to < 1 > or < 2 >, wherein L ¹ ～L ⁵ Each independently represents a phenylene group having a substituent or not, or a group obtained by linking two or more phenylene groups having a substituent or not.

< 4 > the organic electroluminescent element according to < 3 >, wherein L ¹ ～L ⁵ Each independently is a 1, 3-phenylene group with or without substituents.

The organic electroluminescent element according to any one of < 1 > to < 4 >, wherein the molecular weight of the aromatic compound is 1200 or more.

The organic electroluminescent element according to any one of < 1 > to < 5 >, wherein the layer containing the aromatic compound is a light-emitting layer.

< 7 > a display device having the organic electroluminescent element according to any one of < 1 > to < 6 >.

< 8 > an illumination device having the organic electroluminescent element according to any one of < 1 > to < 6 >.

< 9 > an aromatic compound represented by the following formula (1).

[ chemical 4]

(in the formula (1),

L ¹ ～L ⁵ Each independently of the otherAn aromatic hydrocarbon group having 6 to 60 carbon atoms and having a divalent carbon atom which may be substituted or not.

R each independently represents an alkyl group, an alkenyl group, an aryloxy group, an alkoxycarbonyl group, an acyl group, a halogen atom, a haloalkyl group, a silyl group, a siloxy group, an aralkyl group or an aromatic hydrocarbon group.

m1, m2 and m5 each independently represent an integer of 0 to 5.

m3 and m4 each independently represent an integer of 1 to 5.

n represents an integer of 0 to 10.

a1 and a2 each independently represent an integer of 0 to 3.

a3 represents an integer of 0 to 4.

a4 represents an integer of 0 or 1.

Where a4 is 0 when a3 is 4.

In Ar ¹ ～Ar ⁵ A monovalent aromatic hydrocarbon group having 6 to 60 carbon atoms, and L ¹ ～L ⁵ The substituents which the divalent aromatic hydrocarbon group having 6 to 60 carbon atoms may have are each independently an alkyl group, an alkenyl group, an aryloxy group, an alkoxycarbonyl group, an acyl group, a halogen atom, a haloalkyl group, a silyl group, a siloxy group, an aralkyl group or an aromatic hydrocarbon group.

[ chemical 5]

(in the formula (2) or (3),

asterisks indicate the bond with formula (1).

R ¹ ～R ²⁶ Each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an aryloxy group, an alkoxycarbonyl group, an acyl group, a halogen atom, a haloalkyl group, a silane group, a siloxane group, an aralkyl group, or an aromatic hydrocarbon group. )

< 10 > the aromatic compound of < 9 > wherein a1, a2 and a4 are 0.

< 11 > the aromatic compound of < 9 > wherein a4 is 1 and a3 is an integer of 0 to 3.

< 12 > the aromatic compound of < 11 > wherein a1, a2 and a3 are the same.

< 13 > an aromatic compound according to any one of < 9 > to < 12 >, wherein Ar ¹ And Ar is a group ² Ar when n is 1 or more ⁵ Or at least one Ar when n is 2 or more ⁵ Represented by the formula (2) or the formula (3).

< 14 > an aromatic compound according to any one of < 9 > to < 13 >, wherein L ¹ ～L ⁵ Each independently represents a phenylene group having a substituent or not, or a group obtained by linking two or more phenylene groups having a substituent or not.

< 15 > the aromatic compound of < 14 > wherein L ¹ ～L ⁵ Each independently is a1, 3-phenylene group with or without substituents.

An aromatic compound according to any one of < 9 > to < 15 > wherein the molecular weight is 1200 or more.

A composition comprising an aromatic compound according to any one of < 9 > to < 16 > and an organic solvent.

< 18 > the composition according to < 17 > further comprising a phosphorescent light-emitting material and a charge transport material.

< 19 > the composition according to < 18 >, wherein the charge transport material comprises a compound represented by the following formula (250) and/or a compound represented by the following formula (240).

[ chemical 6]

(in the formula (250),

w each independently represents CH or N, and at least one W is N.

Xa ¹ 、Ya ¹ And Za ¹ Each independently represents a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or a divalent aromatic heterocyclic group having 3 to 30 carbon atoms which may have a substituent.

Xa ² 、Ya ² And Za ² Each independently represents a hydrogen atom, a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms with or without a substituent, or a monovalent aromatic heterocyclic group having 3 to 30 carbon atoms with or without a substituent.

g11, h11 and j11 each independently represent an integer of 0 to 6,

at least one of g11, h11, j11 is an integer of 1 or more.

In the case where g11 is 2 or more, a plurality of Xas are present ¹ May be the same or different.

When h11 is 2 or more, a plurality of Ya are present ¹ May be the same or different.

When j11 is 2 or more, a plurality of Za are present ¹ May be the same or different.

R ³¹ Represents a hydrogen atom or a substituent, four R ³¹ May be the same or different.

Wherein, when g11, h11 or j11 is 0, xa corresponds to each ² 、Ya ² 、Za ² Not a hydrogen atom. )

[ chemical 7]

(in 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 and optionally having a substituent.

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

< 20 > the composition according to < 19 > wherein at least two of the three W's in the formula (250) are N.

< 21 > the composition according to < 20 > wherein all W in said formula (250) are N.

< 22 > the composition according to < 19 >, wherein Ar in the formula (240) ⁶¹¹ And Ar is a group ⁶¹² Each independently represents a monovalent group in which a plurality of benzene rings are bonded in a chain or branched manner with or without a substituent.

< 23 > the composition according to < 19 >, wherein R in the formula (240) ⁶¹¹ And R is ⁶¹² Each independently represents a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms and having or not having a substituent.

< 24 > the composition according to < 19 >, wherein n in the formula (240) ⁶¹¹ And n ⁶¹² Each independently is 0 or 1.

A method for forming a thin film, comprising the step of forming a thin film from the composition of any one of < 17 > to < 24 > by a wet film forming method.

< 26 > a method for manufacturing an organic electroluminescent element having an anode and a cathode over a substrate and an organic layer between the anode and the cathode,

has a step of forming the organic layer by a wet film forming method using the composition of any one of < 17 > to < 24 >.

< 27 > the method for manufacturing an organic electroluminescent element according to < 26 >, wherein the organic layer is a light-emitting layer.

< 28 > a method for manufacturing an organic electroluminescent element having an anode and a cathode over a substrate and an organic layer between the anode and the cathode,

The organic layer comprises a light emitting layer and an electron transport layer,

comprising the following steps: a step of forming the light-emitting layer by a wet film formation method using the composition of any one of < 17 > to < 24 >; 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 < 29 > to < 28 > wherein the solvent contained in the composition for forming an electron transport layer is an alcohol-based solvent.

< 30 > an organic electroluminescent element having an anode and a cathode on a substrate, an organic layer between the anode and the cathode, wherein, in the organic electroluminescent element,

the organic layer comprises a light-emitting layer,

the light-emitting layer comprising an aromatic compound, a phosphorescent light-emitting material and a charge transport material according to any one of < 9 > to < 16 >,

the charge transport material includes a compound represented by the following formula (250) and/or a compound represented by the following formula (240).

[ chemical 8]

(in the formula (250),

w each independently represents CH or N, and at least one W is N.

Xa ² 、Ya ² And Za ² Each independently represents a hydrogen atom, a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms with or without a substituent, or a monovalent aromatic group having 3 to 30 carbon atoms with or without a substituentA heterocyclic group.

g11, h11 and j11 each independently represent an integer of 0 to 6,

at least one of g11, h11, j11 is an integer of 1 or more.

[ chemical 9]

(in the formula (240),

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

< 31 > the organic electroluminescent element according to < 30 >, wherein at least two of three W in the formula (250) are N.

< 32 > the organic electroluminescent element according to < 31 >, wherein all W in the formula (250) are N.

[ Effect of the invention ]

According to the present invention, an aromatic compound having excellent heat resistance, solvent solubility and a large band gap can be provided.

The aromatic compound of the present invention is also excellent in solvent resistance against alcohol solvents in films. Therefore, other layers may be laminated on the film containing the aromatic compound of the present invention by a wet film forming method.

According to the present invention, there can be provided: an organic electroluminescent element comprising the aromatic compound, a display device and a lighting device comprising the organic electroluminescent element, a composition comprising the compound and a solvent, a method for forming a thin film, and a method for producing the organic electroluminescent element.

Drawings

Fig. 1 is a cross-sectional view schematically showing an example of the structure 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, "with or without a substituent" means having one or more substituents or not.

[ aromatic Compounds of the invention ]

The aromatic compound contained in the organic layer of the organic electroluminescent element of the present invention is an aromatic compound represented by the following formula (1) (hereinafter, sometimes referred to as "aromatic compound (1)").

[ chemical 10]

(in the formula (1),

m1, m2 and m5 each independently represent an integer of 0 to 5.

m3 and m4 each independently represent an integer of 1 to 5.

n represents an integer of 0 to 10.

a1 and a2 each independently represent an integer of 0 to 3.

a3 represents an integer of 0 to 4.

a4 represents an integer of 0 or 1.

Where a4 is 0 when a3 is 4.

In Ar ¹ ～Ar ⁵ A monovalent aromatic hydrocarbon group having 6 to 60 carbon atoms, and L ¹ ～L ⁵ The substituent which the divalent aromatic hydrocarbon group having 6 to 60 carbon atoms may have is each independently an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyl group, a halogen atom, a haloalkyl group, an alkylthio group, an arylthio group, a silyl group, a siloxy group, an aralkyl group or an aromatic hydrocarbon group.

[ chemical 11]

(in the formula (2) or (3),

asterisks indicate the bond with formula (1).

< mechanism of action of aromatic Compound (1) >)

In the present invention, the mechanism of action by which an effective effect is obtained by the aromatic compound (1) is presumed as follows.

The aromatic compound (1) has one or more terphenyl groups represented by the formula (2) or (3) bonded at the para-position, and therefore has a high glass transition temperature.

The terphenyl group represented by formula (2) or (3) is bonded to formula (1) in the ortho-or meta-position, thereby suppressing expansion of pi-conjugated system, increasing the band gap, increasing the excited triplet level (T1), and decreasing the solubility and crystallinity.

The aromatic hydrocarbon structure represented by the formula (1) has a terphenyl group bonded at the para-position represented by the formula (2) or (3), and thus the solvent resistance of the film to alcohol solvents can be improved.

The aromatic hydrocarbon structure represented by the formula (1) has a terphenyl group bonded at the para position represented by the formula (2) or the formula (3), and the highest occupied molecular orbital (highest occupied molecular orbital, HOMO) and the lowest unoccupied molecular orbital (lowest unoccupied molecular orbital, LUMO) are likely to be locally present in the terphenyl group bonded at the para position represented by the formula (2) or the formula (3), whereby durability can be improved.

By using the aromatic compound (1), an organic electroluminescent element which is excellent in driving stability and can be driven at a low driving voltage and high efficiency can be easily provided.

The organic electroluminescent element of the present invention comprising the aromatic compound (1) is excellent in electrochemical stability, low in driving voltage and high in efficiency. Therefore, the organic electroluminescent element of the present invention can be considered to be applied to a flat panel display (for example, an office automation (office automation, OA) computer display or a wall-mounted television), a vehicle-mounted display element, a light source for displaying on a mobile phone or utilizing characteristics of a surface light emitting body (for example, a light source of a copier, a backlight of a liquid crystal display or an instrument), a display panel, and a sign lamp, and has great technical value.

＜Ar ¹ 、Ar ² 、Ar ⁵ ＞

Ar ¹ 、Ar ² And Ar is a group ⁵ Each independently represents a hydrogen atom or a monovalent aromatic hydrocarbon group having 6 to 60 carbon atoms which may have a substituent.

Ar from the stability point of view ¹ 、Ar ² And Ar is a group ⁵ Preferably, each independently has a structure represented by formula (3).

[ chemical 12]

(in the formula (2) or (3),

asterisks indicate the bond with formula (1).

Ar from the viewpoints of solubility and durability of the compound ¹ 、Ar ² And Ar is a group ⁵ Preferably a hydrogen atom, a monovalent group of a benzene ring, a monovalent group of a naphthalene ring, a structure represented by the formula (2) or (3), more preferably a hydrogen atom, a monovalent group of a benzene ring, a structure represented by the formula (2) or (3)The structure shown is more preferably a hydrogen atom, a monovalent group of a benzene ring, or a structure represented by the formula (3), and most preferably a structure represented by the formula (3).

Ar from the durability standpoint ¹ And Ar is a group ² Ar when n is 1 or more ⁵ Or at least one Ar when n is 2 or more ⁵ The structure represented by the formula (2) or the formula (3) is preferable, and the structure represented by the formula (3) is particularly preferable.

＜Ar ³ 、Ar ⁴ ＞

Ar ³ And Ar is a group ⁴ Each independently represents a hydrogen atom or a monovalent aromatic hydrocarbon group having 6 to 60 carbon atoms which may have a substituent.

Examples of the monovalent aromatic hydrocarbon group having 6 to 60 carbon atoms include benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, tetra-extended benzene ring,Monovalent radicals of rings, pyrene rings, benzanthracene rings, perylene rings, biphenyl rings or terphenyl rings.

Ar from the viewpoints of solubility and durability of the compound ³ 、Ar ⁴ Preferably, each independently represents a hydrogen atom, a monovalent group of a benzene ring, or a monovalent group of a naphthalene ring, and more preferably a hydrogen atom or a monovalent group of a benzene ring.

＜L ¹ ～L ⁵ ＞

Examples of the divalent aromatic hydrocarbon ring having 6 to 60 carbon atoms include benzene ring, naphthalene ring, anthracene ring, tetra-extended benzene ring, phenanthrene ring, and the like,A ring, a pyrene ring, a benzanthracene ring, or a perylene ring, or a divalent group in which two or more of these aromatic hydrocarbon rings are linked by direct bonding.

L ¹ ～L ⁵ Preferably, each independently is a phenylene group having a substituent or not, or a divalent group in which two or more, for example, two to five phenylene groups are linked by direct bonding, and more preferably is a 1, 3-phenylene group having a substituent or not from the viewpoint of solubility.

＜R＞

R each independently represents an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyl group, a halogen atom, a haloalkyl group, an alkylthio group, an arylthio group, a silyl group, a siloxy group, an aralkyl group or an aromatic hydrocarbon group. Specific examples of these substituents and preferred structures are described in substituent group Z described below.

From the viewpoints of heat resistance and durability, R is preferably an alkyl group, an alkenyl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyl group, a halogen atom, a haloalkyl group, a silyl group, a siloxy group, an aralkyl group, or an aromatic hydrocarbon group, more preferably an alkyl group, an alkoxy group, an aralkyl group, or an aromatic hydrocarbon group, further preferably an alkyl group having 10 or less carbon atoms, an aralkyl group having 30 or less carbon atoms, or an aromatic hydrocarbon group having 30 or less carbon atoms, and particularly preferably a benzene ring or a group in which two to five benzene rings are directly bonded.

＜m1～m5＞

m1, m2 and m5 each independently represent an integer of 0 to 5,

m3 and m4 each independently represent an integer of 1 to 5.

From the viewpoints of solubility and durability of the compounds, m1, m2 and m5 are preferably 4 or less, more preferably 3 or less, further preferably 2 or less, particularly preferably 1 or less, and most preferably 0.

From the viewpoints of solubility and durability of the compounds, m3 and m4 are 1 or more, preferably 4 or less, more preferably 3 or less, and particularly preferably 2 or less.

When m1 is 2 or more, a plurality of L' s ¹ May be the same or different. When m2 is 2 or more, a plurality of L ² May be the same or different. When m3 is 2 or more, a plurality of L' s ³ May be the same or different. In the case where m4 is 2 or more,multiple L ⁴ May be the same or different. When m5 is 2 or more, a plurality of L' s ⁵ May be the same or different.

＜Ar ¹ -(L ¹ ) _m1 -、Ar ² -(L ² ) _m2 -、Ar ⁵ -(L ⁵ ) _m5 -＞

Ar from the viewpoint of durability of the Compound ¹ -(L ¹ ) _m1 -、Ar ² -(L ² ) _m2 -、Ar ⁵ -(L ⁵ ) _m5 Preferably, at least one structure represented by the formula (2) or the formula (3), more preferably at least one structure represented by the formula (3), even more preferably at least two structures represented by the formula (3), even more preferably at least three structures represented by the formula (3), and particularly preferably all structures represented by the formula (3).

Ar ¹ -(L ¹ ) _m1 -、Ar ² -(L ² ) _m2 -、Ar ³ -(L ³ ) _m3 -、Ar ⁴ -(L ⁴ ) _m4 None of them are hydrogen atoms.

＜(L ³ ) _m3 、(L ⁴ ) _m4 ＞

From the viewpoints of solubility and durability of the compound, (L) ³ ) _m3 And (L) ⁴ ) _m4 At least one of the structures is preferably at least one selected from the group consisting of a partial structure represented by the following formula (11), a partial structure represented by the following formula (12), and a partial structure represented by the following formula (13).

[ chemical 13]

In each of the formulae (11) to (13), the symbol represents a bond to an adjacent structure or Ar ³ 、Ar ⁴ The hydrogen atom is a hydrogen atom. At least one of the two present indicates a bonding position with an adjacent structure. In the following description, the definitions are the same unless otherwise specified.

More preferably (L) ³ ) _m3 Sum (L) ⁴ ) _m4 At least one of the group (a) and (b) has a partial structure represented by formula (11) or a partial structure represented by formula (12).

Further preferably (L) ³ ) _m3 Sum (L) ⁴ ) _m4 Each having a partial structure represented by formula (11) or a partial structure represented by formula (12).

Particularly preferred is (L) ³ ) _m3 Sum (L) ⁴ ) _m4 The structure has a partial structure represented by formula (11) and a partial structure represented by formula (12), respectively.

The partial structure represented by the following formula (12) is preferable.

[ chemical 14]

The partial structure represented by the following formula (12) is more preferable.

[ 15]

As (L) from the viewpoints of solvent solubility and durability of the compound ³ ) _m3 Sum (L) ⁴ ) _m4 The partial structure of at least one of (2) is preferably a partial structure having the partial structure represented by formula (11) and a partial structure represented by formula (12).

The partial structure having the partial structure represented by the formula (11) and the partial structure represented by the formula (12) is more preferably a structure including a plurality of structures selected from the partial structure represented by the formula (11) and the partial structure represented by the formula (12), that is, a partial structure selected from at least one of the following formulas (14) to (18).

[ 16]

A structure including a plurality of structures selected from the partial structure represented by formula (11) and the partial structure represented by formula (12), for example, the partial structure represented by formula (14) is a partial structure which can be regarded as having one partial structure represented by formula (11) and two partial structures represented by formula (12), as shown in the following formula (14 a).

[ chemical 17]

Further preferably (L) ³ ) _m3 Sum (L) ⁴ ) _m4 At least one of which has a partial structure represented by formula (14) or a partial structure represented by formula (15).

The partial structure represented by the following formula (14) is preferable.

[ chemical 18]

The partial structure represented by the following formula (14) is more preferable.

[ chemical 19]

The partial structure represented by the following formula (15-2) is preferable as the partial structure represented by the formula (15).

[ chemical 20]

The partial structure represented by the following formula (15) is more preferable as the partial structure represented by the following formula (15-3).

[ chemical 21]

/>

The partial structure represented by the following formula (17) is preferable.

[ chemical 22]

The partial structure represented by the following formula (18) is preferable.

[ chemical 23]

(L ³ ) _m3 Sum (L) ⁴ ) _m4 More preferably, the composition has a partial structure represented by the following formula (19) or a partial structure represented by the following formula (20) as a partial structure including a partial structure represented by the formula (13).

[ chemical 24]

In the formulae (14) to (20), respectively, the symbol represents a bond to an adjacent structure, or Ar ³ 、Ar ⁴ The hydrogen atom is a hydrogen atom. At least one of the two is present to indicate a bonding position with an adjacent structure.

Of the partial structures represented by the formulas (14) to (20), the partial structure represented by the formula (14-3) and the partial structure represented by the formula (15-3) are preferable, and the formula (14-3) is more preferable.

＜L ¹ ～L ⁵ Preferred partial structure of (2)

In the formula (1)，L ¹ ～L ⁵ Preferably has a partial structure represented by formula (12-3), a partial structure represented by formula (14-3), or a partial structure represented by formula (15-3).

＜n＞

n represents an integer of 0 to 10.

From the viewpoints of solubility and durability of the compound, n is preferably 1 or more, more preferably 2 or more, and preferably 6 or less, more preferably 5 or less, and particularly preferably 4 or less.

＜a1～a4＞

a1 and a2 each independently represent an integer of 0 to 3.

a3 represents an integer of 0 to 4.

a4 represents an integer of 0 or 1.

Where a4 is 0 when a3 is 4.

From the viewpoints of solubility and durability of the compounds, a1 to a4 are preferably a combination of the following.

a1 An integer of a2=a4=0, and a3=0 to 4;

a1 A2=a4=0, and a3=0 or 1;

a1＝a2＝a3＝a4＝0；

a4 =1, and a1=a2=a3;

a4 =1, and a1 to a3 are each independently integers from 0 to 3;

a4 =1, and a1 to a3 are each independently 0 or 1;

a4 =1, and a1=a2=a3=0 or 1;

further preferred is

a1＝a2＝a3＝a4＝0；

a4 =1, and a1=a2=a3=0.

That is, from the viewpoints of solubility and durability of the compounds, a1 to a3 are preferably each independently 0 or 1, and most preferably 0.

＜R ¹ ～R ²⁶ ＞

R ¹ ～R ²⁶ Each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyl group, a halogen atom, a haloalkyl group, an alkylthio group, an arylthio group, a silyl group, a siloxy group, an aralkyl group, or an aromatic hydrocarbon group.

Specific examples of these substituents and preferred structures are described in substituent group Z described below.

From the viewpoint of durability, R ¹ ～R ²⁶ Preferably, each independently is a hydrogen atom, an alkyl group, an alkenyl group, an aryloxy group, an alkoxycarbonyl group, an acyl group, a halogen atom, a haloalkyl group, a silyl group, a siloxy group, an aralkyl group, or an aromatic hydrocarbon group, more preferably a hydrogen atom or an aromatic hydrocarbon group, and particularly preferably a hydrogen atom.

< substituent >

In Ar ¹ ～Ar ⁵ A substituent which may be contained in a monovalent aromatic hydrocarbon group having 6 or more and 60 or less of a carbon number, and L ¹ ～L ⁵ The substituents which the divalent aromatic hydrocarbon group having 6 to 60 carbon atoms may have are each independently an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyl group, a halogen atom, a haloalkyl group, an alkylthio group, an arylthio group, a silyl group, a siloxy group, an aralkyl group or an aromatic hydrocarbon group, and preferably are each independently an alkyl group, an alkenyl group, an aryloxy group, an alkoxycarbonyl group, an acyl group, a halogen atom, a haloalkyl group, a silyl group, a siloxy group, an aralkyl group or an aromatic hydrocarbon group.

As the Ar ¹ ～Ar ⁵ 、L ¹ ～L ⁵ May have a substituent, the R and R ¹ ～R ²⁶ Specifically, the substituents described in the substituent group Z below are exemplified.

Substituent group Z >

Substituent group Z is a substituent group including an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyl group, a halogen atom, a haloalkyl group, an alkylthio group, an arylthio group, a silyl group, a siloxy group, a cyano group, an aralkyl group, and an aromatic hydrocarbon group.

Examples of the alkyl group include: a methyl group; an ethyl group; branched, straight-chain or cyclic propyl; branched, straight-chain or cyclic butyl; branched, straight or cyclic pentyl; branched, straight-chain, or cyclic hexyl; branched, straight-chain or cyclic octyl; branched, straight chain or cyclic nonyl; a linear, branched or cyclic alkyl group having not less than 1, preferably not less than 4, and not more than 24, preferably not more than 10, carbon atoms such as a branched, linear or cyclic dodecyl group. From the viewpoint of stability of the compound, methyl, ethyl, branched, straight-chain or cyclic propyl, branched, straight-chain or cyclic butyl are preferable; particularly preferred is a branched propyl group.

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.

Examples of the alkoxy group include an alkoxy group having usually 1 to 24 carbon atoms, preferably 12 carbon atoms, such as a methoxy group and an ethoxy group.

Examples of the aryloxy group include an aryloxy group or a heteroaryloxy group having usually 4 or more carbon atoms, preferably 5 or more carbon atoms and usually 36 or less carbon atoms, preferably 24 or less carbon atoms, such as a phenoxy group, a naphthyloxy group and a pyridyloxy group.

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

Examples of the acyl group include acyl groups 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.

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

Examples of the haloalkyl group include haloalkyl groups having usually 1 to 12 carbon atoms, preferably 6 carbon atoms, such as trifluoromethyl.

Examples of the alkylthio group include alkylthio groups having usually 1 to 24 carbon atoms, preferably 12 carbon atoms, such as a methylthio group and an ethylthio group.

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

Examples of the silane group include silane groups 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 trimethylsilyl group and triphenylsilyl group.

Examples of the siloxy group include 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.

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.

Examples of the aromatic hydrocarbon group include benzene ring, naphthalene ring, anthracene ring, tetra-extended benzene ring, phenanthrene ring, and the like,An aromatic hydrocarbon group having a carbon number of usually 6 or more and usually 30 or less, preferably 18 or less, and more preferably 10 or less, such as a ring, pyrene ring, benzanthracene ring, perylene ring, or the like.

Among the substituent groups Z, an alkyl group, an alkoxy group, an aralkyl group, and an aromatic hydrocarbon group are preferable, an alkyl group having 10 or less carbon atoms, an aralkyl group having 30 or less carbon atoms, and an aromatic hydrocarbon group having 30 or less carbon atoms are more preferable, an aromatic hydrocarbon group having 30 or less carbon atoms is more preferable, and a substituent-free group is particularly preferable.

Each substituent of the substituent group Z may have a further substituent. As further substituents of these, the same substituents as the substituents (substituent group Z) can be used. The substituents of the substituent group Z preferably have no further substituents.

< molecular weight >

The molecular weight of the aromatic compound (1) is preferably 1000 or more, more preferably 1100 or more, particularly preferably 1200 or more, most preferably 1300 or more, and preferably 5000 or less, more preferably 4000 or less, particularly preferably 3000 or less, most preferably 2000 or less.

Specific example >

Specific examples of the aromatic compound (1) are shown below, but the present invention is not limited to these.

[ chemical 25]

[ chemical 26]

[ chemical 27]

[ chemical 28]

[ chemical 29]

[ chemical 30]

[ 31]

[ chemical 32]

[ 33]

[ chemical 34]

[ 35]

Process for producing aromatic compound (1)

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

Use of aromatic Compound (1)

The aromatic compound (1) is preferably an organic layer used in an organic electroluminescent element, and the organic layer is preferably a light-emitting layer. In the case where the aromatic compound (1) is used for the light-emitting layer, it is preferable to use the aromatic compound as a host material for the light-emitting layer.

The organic layer containing the aromatic compound (1) may be formed by vapor deposition or wet film formation. Since the organic layer containing the aromatic compound (1) can be formed into a more uniform film, it is particularly preferably formed by a wet film forming method.

[ aromatic Compounds of the invention ]

The aromatic compound of the present invention is an aromatic compound represented by the following formula (1), and is one form of the aromatic compound (1).

[ 36]

(in the formula (1),

m1, m2 and m5 each independently represent an integer of 0 to 5.

m3 and m4 each independently represent an integer of 1 to 5.

n represents an integer of 0 to 10.

a1 and a2 each independently represent an integer of 0 to 3.

a3 represents an integer of 0 to 4.

a4 represents an integer of 0 or 1.

Where a4 is 0 when a3 is 4.

[ 37]

/>

(in the formula (2) or (3),

asterisks indicate the bond with formula (1).

In the aromatic compound of the present invention, R, ar in the formula (1) ¹ ～Ar ⁵ A monovalent aromatic hydrocarbon group having 6 to 60 carbon atoms, and L ¹ ～L ⁵ R in the formula (2) and the formula (3) is a substituent which may be contained in a divalent aromatic hydrocarbon group having 6 to 60 carbon atoms ¹ ～R ²⁶ The description of the aromatic compound (1) is applicable to the same as the aromatic compound (1), except that these are further limited based on the aromatic compound (1).

The preferred form and specific examples of the aromatic compound of the present invention are the same as those of the aromatic compound (1).

[ composition ]

When the organic layer containing the aromatic compound of the present invention is subjected to a wet film forming method, at least the composition containing the aromatic compound of the present invention represented by the above formula (1) and an organic solvent is subjected to a wet film forming. The composition of the present invention comprises at least the aromatic compound of the present invention and an organic solvent.

The composition of the present invention may contain only one kind of the aromatic compound of the present invention, or may contain two or more kinds.

The composition of the present invention preferably further comprises a luminescent material, preferably a phosphorescent luminescent material, and a charge transport material. The composition of the present invention can be preferably 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 aromatic compound of the present invention by wet film formation.

The organic solvent is not particularly limited as long as it is an organic solvent in which the aromatic compound of the present invention and a light-emitting 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 viewpoint of viscosity and boiling point, alkanes, aromatic hydrocarbons, aromatic ethers, and aromatic esters are preferable, aromatic hydrocarbons, aromatic ethers, and aromatic esters are more preferable, and aromatic hydrocarbons and aromatic esters are particularly preferable.

These organic solvents may be used singly or in any combination and ratio.

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, there is a possibility that 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 in 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 means a component that mainly emits light 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 materials)

Phosphorescent light-emitting materials refer to materials that exhibit luminescence from an excited triplet state. For example, a metal complex compound having Ir, pt, eu, or the like is typical thereof, and the material structure is preferably a metal complex.

Among the metal complexes, phosphorescent organometallic complexes that emit light through a triplet state include wiener (Werner) type complexes or organometallic complex compounds that contain 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).

[ 38]

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 with or without a substituent, or an aromatic heterocyclic structure with or without a substituent.

Ring A2 represents an aromatic heterocyclic structure with or without 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 plural ones are present, they may be the same or different.

Ar in formula (202) ²⁰¹ 、Ar ²⁰³ Each independently represents an aromatic hydrocarbon ring structure with or without a substituent, or an aromatic heterocyclic structure with or without a substituent.

Ar ²⁰² An aromatic hydrocarbon ring structure with or without a substituent, an aromatic heterocyclic structure with or without a substituent, or an aliphatic hydrocarbon structure with or without 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 And 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 with B ²⁰¹ And B ²⁰² Together forming a group of bidentate ligands. In a plurality of presence B ²⁰¹ -L ²⁰⁰ -B ²⁰² In the case of (2), they 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 ²⁰² The number of substitutions is an integer of 0 or more as an upper limit.

j is as follows ²⁰¹ The number of substitutions is an integer of 0 or more as an upper limit.

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

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 triphenylene ring (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, and a quinazoline ring, and most preferred are a pyridine ring, an imidazole ring, a benzothiazole ring, a quinoline ring, a quinoxaline ring, and a 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 either of them is an aromatic hydrocarbon ring structure having a substituent or not, the aromatic hydrocarbon ring structure is preferably an aromatic hydrocarbon ring having 6 to 30 carbon atoms,

specifically, benzene ring, naphthalene ring, anthracene ring, triphenylene ring, acenaphthene ring, fluor anthracene 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 either one of the fluorene rings is a fluorene ring with or without a substituent, the 9-position and 9' -position of the fluorene ring are preferably substituted or bonded to an adjacent structure.

In Ar ²⁰¹ 、Ar ²⁰² 、Ar ²⁰³ In the case where the benzene ring is one having a substituent or not, at least one benzene ring is preferably bonded to an adjacent structure in the ortho-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 is an aromatic heterocyclic structure having a substituent or not, the heterocyclic aromatic structure is preferably an aromatic heterocyclic ring having 3 to 30 carbon atoms which contains 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 is a carbazole ring with or without a substituent, the N-position of the carbazole ring is preferably substituted or bonded to an adjacent structure.

In Ar ²⁰² In the case of an aliphatic hydrocarbon structure having a substituent or not, the aliphatic hydrocarbon structure is an aliphatic hydrocarbon structure having a linear, branched or cyclic structure, preferably an aliphatic hydrocarbon having 1 to 24 carbon atoms, more preferably 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 representing 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 which 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 by 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 by 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 of substituent group S, and the like.

(preferred Structure of formula (201))

Among the structures represented by the formula (202) in the formula (201), it is preferable that (i) the structure has a group to which a benzene ring is bonded, (ii) the structure has 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, and (iii) the structure has a tree-like motif (dendron) 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 ring A1 or 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 ²⁰¹ The aromatic hydrocarbon structure is preferably a structure in which one to five benzene rings are linked, and more preferably one benzene ring.

(iii) Ar in the structure in which a dendron is 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), at B ²⁰¹ -L ²⁰⁰ -B ²⁰² Among the structures represented, the structure represented by the following formula (203) or formula (204) is preferable.

[ 39]

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.

[ 40]

In the formula (204), the ring B3 represents an aromatic heterocyclic structure containing a nitrogen atom with or without 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.

[ chemical 41]

[ chemical 42]

[ chemical 43]

[ 44]

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

[ 45]

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 And R is 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 And R is 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, when T is a carbon atom, R ⁹⁴ And R is ⁹⁵ Respectively and independently represent R ⁹² And R is ⁹³ The same illustrations represent substituents. 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 And R is ⁹³ And the substituents listed. Further, R is 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, phosphorescent 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 to contain a charge transport material as a further host material in addition to the aromatic 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.

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, triphenylene structures, carbazole structures, pyrene structures, anthracene structures, phenanthroline structures, quinoline structures, pyridine structures, pyrimidine structures, triazine structures, oxadiazole structures, imidazole structures, or the like.

The electron-transporting material is more preferably a compound having a pyridine structure, a pyrimidine structure and/or a triazine structure, which is excellent in electron-transporting property and relatively stable in structure, and further preferably a compound having a pyrimidine structure and/or a triazine structure. Particularly preferred is a compound represented by the following formula (250).

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.

When the composition of the present invention is a composition for forming a light-emitting layer, it is preferable that the composition further contains, as a host material, a compound represented by the following formula (250) and/or a compound represented by the following formula (240), in addition to the aromatic compound of the present invention. From the viewpoint of charge balance adjustment in the light-emitting layer and the viewpoint of light-emitting efficiency, it is preferable to include such a material as a further host material.

The charge transport material used as the host material of the light-emitting layer is preferably a compound having a condensed ring structure of three or more rings, more preferably a compound having a condensed ring structure of two or more rings or a compound having at least one condensed ring of five or more rings. 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,A structure, a naphthacene structure, a triphenylene structure, a fluorene structure, a benzofluorene structure, an indenofluorene structure, an indolofluorene structure, a carbazole structure, an indenocarbazole structure, an indolocarbazole structure, a dibenzofuran structure, a 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.

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. In the case where 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 a solvent. In the case where 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 600 or more, preferably 800 or more. When a layer formed by contact with the light-emitting layer is formed by a wet film formation method, the molecular weight of the low-molecular charge transport material is preferably 1000 or more, more preferably 1100 or more, and particularly preferably 1200 or more.

< Compound represented by formula (250) >)

[ chemical 46]

(in the formula (250),

w each independently represents CH or N, and at least one W is N.

Xa ¹ 、Ya ¹ And Za ¹ Each independently represents a divalent group having 6 to 30 carbon atoms with or without a substituentAn aromatic hydrocarbon group, or a divalent aromatic heterocyclic group having 3 to 30 carbon atoms which may have a substituent.

g11, h11 and j11 each independently represent an integer of 0 to 6,

at least one of g11, h11, j11 is an integer of 1 or more.

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

(W)

W in formula (250) represents CH or N, at least one of which is N. From the viewpoints of electron transport property and electron durability, at least two of W are preferably N, and more preferably all are N.

＜Xa ¹ 、Ya ¹ 、Za ¹ 、Xa ² 、Ya ² 、Za ² ＞

As Xa in formula (250) ¹ 、Ya ¹ 、Za ¹ In the case of a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, and Xa ² 、Ya ² 、Za ² An aromatic hydrocarbon group having 6 to 30 carbon atoms, in the case of a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms with or without a substituentThe aromatic hydrocarbon ring is preferably a single ring of six-membered ring, or two to five condensed rings. Specifically, there may be mentioned: benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, fluorene ring, perylene ring, tetracene ring, pyrene ring, benzopyrene ring,Ring, triphenylene ring, fluoranthene ring, indenofluorene ring, and the like. Among them, a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, or a fluorene ring is preferable, a benzene ring, a naphthalene ring, a phenanthrene ring, or a fluorene ring is more preferable, and a benzene ring, a naphthalene ring, or a fluorene ring is further preferable.

As Xa in formula (250) ¹ 、Ya ¹ 、Za ¹ In the case of a divalent aromatic heterocyclic group having 3 to 30 carbon atoms which may have a substituent, and Xa ² 、Ya ² 、Za ² In the case of a monovalent aromatic heterocyclic group having 3 to 30 carbon atoms which may have a substituent, the aromatic heterocyclic group is preferably a monocyclic ring of a five-membered ring or a six-membered ring, or a two to five condensed rings. Specifically, there may be mentioned: furan ring, benzofuran ring, dibenzofuran ring, thiophene ring, benzothiophene ring, dibenzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, indolocarbazole ring, indenocarbazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, furopyrrole ring, furan ring, thienofuran ring, benzisoxazole ring, benzisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, cinnoline ring, quinoxaline ring, piperidine ring, quinazoline ring, quinazolinone ring, and the like. Among them, a thiophene ring, a pyrrole ring, an imidazole ring, a pyridine ring, a pyrimidine ring, a triazine ring, a quinoline ring, a quinazoline ring, a carbazole ring, a dibenzofuran ring, a dibenzothiophene ring, an indolocarbazole ring, a phenanthroline ring, or an indenocarbazole ring is preferable, a pyridine ring, a pyrimidine ring, a triazine ring, a quinoline ring, a quinazoline ring, a carbazole ring, a dibenzofuran ring, or a dibenzothiophene ring is more preferable, and a carbazole ring, a dibenzofuran ring, or a dibenzothiophene ring is more preferable Dibenzothiophene ring.

Xa in formula (250) ¹ 、Ya ¹ 、Za ¹ 、Xa ² 、Ya ² And Za ² In particular, the aromatic hydrocarbon ring is preferably a benzene ring, naphthalene ring or phenanthrene ring. Particularly preferred aromatic heterocycles are carbazole, dibenzofuran or dibenzothiophene rings.

(g11、h11、j11)

g11, h11 and j11 each independently represent an integer of 0 to 6, and at least one of g11, h11 and j11 is an integer of 1 or more. From the viewpoints of charge transport property and durability, g11 is preferably 2 or more, or at least one of h11 and j11 is preferably 3 or more.

From the viewpoints of charge transport property, durability, and solubility in an organic solvent, the compound represented by formula (250) preferably has 8 to 18 total rings including a ring having three W in the center.

(R ³¹ )

Regarding R when used as a substituent ³¹ The aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent or the aromatic heterocyclic group having 3 to 30 carbon atoms which may have a substituent is preferable. From the viewpoints of durability improvement and charge transport property, R ³¹ More preferably an aromatic hydrocarbon group having a substituent or not. R in the presence of a plurality of substituents ³¹ May be different from each other.

R as a substituent which may be contained in the aromatic hydrocarbon group having 6 to 30 carbon atoms or a substituent which may be contained in the aromatic heterocyclic group having 3 to 30 carbon atoms ³¹ The substituent which may be present may be selected from the following substituent group Z2.

(substituent group Z2)

Substituent group Z2 is a group comprising alkyl, alkoxy, aryloxy, heteroaryloxy, alkoxycarbonyl, dialkylamino, diarylamino, arylalkylamino, acyl, halogen atom, haloalkyl, alkylthio, arylthio, silyl, siloxy, cyano, aromatic hydrocarbon, and aromatic heterocyclic group. These substituents may also comprise 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 arylalkylamine group having a carbon number of usually 7 or more and usually 36 or less, preferably 24 or less, such as a phenylmethylamino group;

for example, an acyl group having a carbon number of usually 2 or more and usually 24 or less, preferably 12, such as an acetyl group or 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 usually 6 or more and usually 36 or less, preferably 24 or less carbon atoms such as a phenyl group and 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 properties, the substituent is more preferably an aromatic hydrocarbon group or an aromatic heterocyclic group, still more preferably an aromatic hydrocarbon group, and particularly 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 Z2 may have a further 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. From the viewpoint of charge transport property, each substituent of the substituent group Z2 more preferably has no further substituent.

(molecular weight)

The compound represented by formula (250) is a low molecular material. The molecular weight of the compound represented by the formula (250) is preferably 3,000 or less, more preferably 3,000 or less, further preferably 2,000 or less, particularly preferably 1,500 or less. The lower limit of the molecular weight of the compound is usually 300 or more, preferably 350 or more, more preferably 400 or more.

(specific example of the compound represented by the formula (250))

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

[ 47]

[ 48]

The composition of the present invention may contain only one kind of the compound represented by the formula (250), or may contain two or more kinds.

< Compound represented by formula (240) >)

[ 49]

(in the formula (240),

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

(Ar ⁶¹¹ 、Ar ⁶¹² )

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

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, tetra-extended benzene ring, phenanthrene ring, and the like,A monovalent group having an aromatic hydrocarbon structure in which a carbon number such as a ring, a pyrene ring, a benzanthracene ring, or a perylene ring 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 generally used, and a structure in which two to five are linked is preferable. In the case of connecting a plurality of aromatic hydrocarbon rings, the same structure may be connected, or different structures may be connected.

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,

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

monovalent radicals formed by linking one or more benzene rings and at least one phenanthrene ring in a chain or branched manner, or

A monovalent group comprising one or more benzene rings and at least one tetraextended benzene ring bonded in a chain or branched manner,

these may have a substituent. 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 either case, the order of bonding may be arbitrary.

Ar ⁶¹¹ 、Ar ⁶¹² Particularly preferred are monovalent groups each independently having a plurality of benzene rings bonded in a chain or branched manner, each of which may have a substituent, and most preferred are monovalent groups each independently having a plurality of benzene rings bonded in a chain or branched manner.

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, preferred are monovalent groups having one to four benzene rings bonded thereto, monovalent groups having one to four benzene rings bonded thereto and naphthalene rings bonded thereto, monovalent groups having one to four benzene rings bonded thereto and phenanthrene rings bonded thereto, and monovalent groups having one to four benzene rings bonded thereto and tetralin rings bonded thereto.

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.

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).

[ 50]

/>

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

More preferably Ar ⁶¹¹ 、Ar ⁶¹² Has at least one partial structure selected from the group consisting of formula (72-1) to formula (72-4) and formula (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.

[ 51]

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

[ 52]

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

(R ⁶¹¹ 、R ⁶¹² )

R ⁶¹¹ 、R ⁶¹² Each independently represents a halogen atom such as a deuterium atom or a fluorine atom, or a monovalent aromatic hydrocarbon group having 6 to 50 carbon atoms and having or not having a substituent.

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

The aromatic hydrocarbon group is preferably a monovalent group 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, specifically with Ar ⁶¹¹ The same applies to preferred aromatic hydrocarbon groups, and phenyl is particularly preferred.

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

(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 provided is preferably a substituent selected from the substituent group Z2.

(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, tetra-extended benzene ring, phenanthrene ring, and the like,A divalent group having an aromatic hydrocarbon structure in which a carbon number such as a ring, a pyrene ring, a benzanthracene ring, or a perylene ring 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 generally used, and a structure in which two to five are linked is preferable. When a plurality of aromatic hydrocarbon rings are connected, the same structure may be connected, or different structures may be connected.

G is preferably

A single bond,

Phenylene group,

Divalent groups in which a plurality of benzene rings are bonded in a chain or branched manner,

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

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

A divalent group comprising one or more benzene rings and at least one tetraextended benzene ring 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 generally 2 to 8, preferably 2 to 5, as described above. Of these, a divalent group having one to four benzene rings bonded thereto, a divalent group having one to four benzene rings and a naphthalene ring bonded thereto, a divalent group having one to four benzene rings and a phenanthrene ring bonded thereto, or a divalent group having one to four benzene rings and a tetralin ring bonded thereto is further preferable.

(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 example of the compound 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.

[ 53]

The composition of the present invention may contain only one kind of the compound represented by the formula (240), or may contain 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, dimethyl sulfoxide, and the like.

The composition of the present invention may contain various additives such as leveling agents and defoaming agents.

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 solidified and insoluble after film formation.

< mix ratio >

The concentration of the solid content in the composition of the present invention (the concentration of all solid components including the aromatic compound of the present invention, the light-emitting material, the host material other than the aromatic compound of the present invention, and 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 usually 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 to easily form a thin film having a desired film thickness with a uniform thickness.

The preferable mixing ratio of the aromatic compound and the light-emitting material of the present invention to all host materials contained in the composition of the present invention, that is, the preferable mixing ratio of the compound and the light-emitting material of the present invention 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 whole host materials refer to the aromatic compound of the present invention and all host materials other than the aromatic compound of the present invention.

The mass ratio of the aromatic compound of the present invention to the total mass 100 of the host materials in the composition of the present invention and the light-emitting layer of the present invention is usually 1 or more, preferably 5 or more, more preferably 10 or more, still more preferably 15 or more, and is usually 90 or less, preferably 80 or less, more preferably 70 or less, and particularly preferably 50 or less.

The molar ratio of the aromatic 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 1 mol% or more, preferably 5 mol% or more, more preferably 10 mol% or more, particularly preferably 15 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 lower than the lower limit or exceeds the upper limit, the luminous efficiency may be significantly reduced.

Preparation method of the composition

The composition of the present invention is prepared by dissolving a solute comprising the aromatic compound of the present invention, a light-emitting material such as the phosphorescent light-emitting material, if necessary, a charge transport material, and a host material other than the aromatic compound of the present invention, and various additive components such as a leveling agent and 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 in the case where 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 water concentration in the composition, a method described in Japanese Industrial Standard "chemical moisture measurement method" (Japanese Industrial Standard (Japanese Industrial Standards, JIS K0068:2001) is preferable, and for example, analysis can be performed by the Karl Fischer's reagent method (JIS K0211-1348) or the like.

(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 liquid state which is uniform at normal 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.

(physical Properties)

When the viscosity of the composition of the present invention is extremely low, for example, uneven coating surface 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. The heat drying may be performed after the natural drying or the reduced pressure drying in order to further remove the residual organic solvent.

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 further 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.

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

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

The aliphatic alcohol having 6 or more carbon atoms is more preferable in terms of easy dissolution of the electron transporting material and easy formation of a flat film having a moderately high boiling point.

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 by mixing two or more kinds.

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

[ 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 transparent synthetic resin plate such as a glass plate, 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 performs a function of 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, and conductive polymers such as poly (3-methylthiophene), polypyrrole, polyaniline, and the like.

The anode 2 is usually formed by a dry method such as a sputtering method or a vacuum deposition method. When the anode is formed using fine metal particles such as silver, fine particles such as copper iodide, carbon black, fine conductive metal oxide particles, fine conductive polymer 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, a thin film may be formed directly on the substrate by electrolytic polymerization, or the conductive polymer may be coated on the substrate to form an anode (applied physical report, pp. 2711, 1992, 60).

The anode 2 is usually of a single-layer structure, but may be suitably formed of a laminated structure. In the case where the anode 2 has a laminated structure, a different conductive material 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 such that the transmittance of visible light is 60% or more, and more preferably such that 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 have 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, and argon plasma before forming the film, thereby removing impurities on the anode 2 and adjusting ionization energy thereof to improve hole injection property.

< hole injection layer >)

The layer that performs a 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 that perform 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 a composition having high hole transport properties and capable of efficiently transporting injected holes. 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 composition has excellent stability, small ionization energy 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 the light emission from the light-emitting layer is not quenched or an exciplex (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 an ionization energy 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 amorphism 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.

In the case of forming the hole injection layer 3 by a wet film forming method, a composition for film formation (composition for forming a hole injection layer) is generally prepared by mixing a material for forming the hole injection layer 3 with an organic solvent (solvent for a 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 applying the composition to 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.

In the case of forming the hole injection layer 3 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, each crucible is usually heated), and the evaporation amount of the material in the crucible is controlled while being evaporated (in the case of using two or more materials, the evaporation amount is usually controlled while being evaporated independently, respectively), and the hole injection layer 3 is formed on the anode 2 on the substrate 1 placed facing the crucible. In the case of using two or more materials, 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 that plays a role 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 typically 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 ionization energy is small, the transparency to light of visible light is high, 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 is reduced without quenching luminescence from the light emitting layer 5 or without forming an exciplex with the light emitting layer 5.

As a material of the hole transport layer 4, a material conventionally used as a constituent material of a hole transport layer may be used, 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 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 or a so-called dendrimer (dendrimer) having branches in the main chain and three or more terminal portions 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.

[ 54]

(in the formula (II), ar ^a And Ar is a group ^b Each independently represents an aromatic hydrocarbon group having or not having a substituent, or an aromatic heterocyclic group having or not having a substituent. )

As the polyarylene derivative, there may be mentioned a polymer having the following groups as its repeating units: an aromatic hydrocarbon group having or not having a substituent, or an arylene group such as an aromatic heterocyclic group having or not having a substituent.

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.

[ 55]

(in the formula (III-1), R ^a 、R ^b 、R ^c And R is ^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 adjacent ^a Or R is ^b May form a ring with each other. )

[ 56]

(in the formula (III-2), R ^e And R is ^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 contained in one molecule ^e And R is ^f R, which may be identical or different, are adjacent ^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 with or without a substituent, a nitrogen atom with or without a substituent, a silicon atom with or without a substituent, a phosphorus atom with or without a substituent, a sulfur atom with or without a substituent, a carbon atom with or without 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).

[ 57]

(in the formula (III-3), ar ^c ～Ar ⁱ Each independently represents an aromatic hydrocarbon group having or not having a substituent, or an aromatic heterocyclic group having or not having 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 wet film formation is followed by heat drying.

The hole transport layer-forming composition 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 also 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 oxetanes and epoxides; 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 with respect to the hole-transporting compound. 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.

< luminescent layer >)

The light-emitting layer 5 is a layer that performs a 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 according to the present invention is formed by the composition according to the present invention by a wet film formation method.

The light-emitting layer formed using the composition of the present invention preferably contains the aromatic compound of the present invention, a phosphorescent light-emitting material, and a charge transport material, and contains the compound represented by the formula (250) and/or the compound represented by the formula (240) as the charge transport 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 injection layer 6 described later. 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 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-quinolinolato) aluminum-mu-oxo-bis- (2-methyl-8-quinolinolato) aluminum binuclear metal complexes, styryl compounds such as distyrylbiphenyl 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), and phenanthroline derivatives such as bathocuproine (JP-A-10-79297), and the like. Furthermore, 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-type hydrogenated amorphous silicon carbide, N-type zinc sulfide, N-type zinc selenide, and the like.

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

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 transport material represented by a nitrogen-containing heterocyclic compound such as bathophenanthranthline 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-A10-270171, JP-A2002-100478 or JP-A2002-100482).

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 on 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 a 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 being stable to the atmosphere over 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 structure in which a plurality of organic electroluminescent elements are arranged in an array may be used, or a structure in which anodes and cathodes are arranged in an X-Y matrix may be used.

[ 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. The type or structure of the organic EL display 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.

For example, the organic EL display device of the present invention can be formed by a method described in "organic EL display (organic EL dub) (issue of omu corporation (Ohmsha) at 8/20/2004), ren Jingshi, the ampere thousand wave 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.

The organic electroluminescent element of the present invention is used in a display device such as an organic EL display or an illumination device such as an organic EL illumination. The organic electroluminescent element of the present invention can be used to form an organic EL display or an organic EL lighting by a method described in, for example, an "organic EL display (with a power unit) (omsha), release at 8/20/2004, ren Jingshi, an ampoul, or Tian Yingxing.

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 exceeding the gist thereof.

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, and DMSO means dimethyl sulfoxide.

Comparative compound 1 and comparative compound 2 were synthesized according to the method described in patent document 1 (international publication No. 2007/043357).

Synthesis example I-1: synthesis example of Compound (H-1)

< Synthesis of Compounds 1-c >

[ 58]

To compound 1-a (14.1 g,30.4 mmol) and compound 1-b (7.23 g,20.3 mmol) were added toluene (130 mL), ethanol (30 mL) and an aqueous tripotassium phosphate solution, which were subjected to nitrogen bubbling, in this order, under a nitrogen atmosphere(2.0 mol/L,30 mL) and heated to 60 ℃. After that, pd (PPh) ₃ ) ₄ (0.23 g,0.20 mmol) was stirred with heating at 90℃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 off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain compound 1-c (yield 9.0g, yield 72%).

(Synthesis of Compound (H-1))

[ 59]

To compound 1-c (2.0 g,3.26 mmol), compound 1-d (0.66 g,1.63 mmol) were successively added toluene (40 mL), ethanol (20 mL), and an aqueous tripotassium phosphate solution (2.0 mol/L,20 mL) which were nitrogen-bubbled under a nitrogen atmosphere, and heated to 60 ℃. After that, pd (PPh) ₃ ) ₄ (0.23 g,0.20 mmol) was heated and stirred at 90℃for 5 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 off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain compound (H-1) (yield 1.44g, yield 72%).

Synthesis example I-2: synthesis example of Compound (H-2)

< Synthesis of Compound 2-c >

[ chemical 60]

To compound 2-a (10.6 g,26.1 mmol), compound 2-b (16.2 g,57.4 mmol) were successively added toluene (130 mL), ethanol (65 mL), and an aqueous solution of tripotassium phosphate (2.0 mol/L,65 mL) with nitrogen bubbling, and heated to 50 ℃. Thereafter, pdCl is added ₂ (PPh ₃ ) ₂ (0.37 g,0.52 mmol) was stirred at 65 ℃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 off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain compound 2-c (yield 9.12g, yield 75%).

< Synthesis of Compound 2-d >

[ chemical 61]

To compound 2-c (9.12 g,19.6 mmol), bis (pinacolato diboron) (15.0 g,58.9 mmol), potassium acetate (11.5 g,117.6 mmol) was added anhydrous DMSO (200 mL) and heated to 50 ℃. Adding PdCl ₂ (dppf)CH ₂ Cl ₂ (0.80 g,0.98 mmol) was stirred at 90℃for 3 hours. After cooling to room temperature, distilled water was added, and suction filtration was performed. The filtrate was dissolved in toluene, washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and then distilled off 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 73%).

< Synthesis of Compound (H-2) ]

[ 62]

To compound 1-c (9.4 g,15.4 mmol), compound 2-d (3.9 g,6.99 mmol) were successively added toluene (60 mL), ethanol (30 mL), and an aqueous tripotassium phosphate solution (2.0 mol/L,30 mL) which were nitrogen-bubbled under a nitrogen atmosphere, and heated to 60 ℃. After that, pd (PPh) ₃ ) ₄ (0.081 g,0.070 mmol) was stirred with heating at 90℃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 off under reduced pressure. Subjecting the residue to silica gel column chromatography Thus, compound (H-2) was obtained (yield 8.0g, yield 83%).

Synthesis example I-3: synthesis of Compound (H-3)

< Synthesis of Compound 3-a >

[ 63]

To compound 1-c (4.60 g,7.5 mmol), bis (pinacolato diboron) (2.85 g,11.2 mmol), potassium acetate (2.21 g,22.5 mmol) was added anhydrous DMSO (60 mL) and heated to 50 ℃. Adding PdCl ₂ (dppf)CH ₂ Cl ₂ (0.31 g,0.38 mmol) was stirred at 90℃for 2 hours. After cooling to room temperature, distilled water was added, and suction filtration was performed. The filtrate was dissolved in toluene, washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and then distilled off under reduced pressure to remove the solvent. The residue was subjected to silica gel column chromatography to obtain compound 3-a (yield 4.88g, yield 98%).

< Synthesis of Compound (H-3) >)

[ 64]

To compound 3-a (4.88 g,7.39 mmol), compound 1-a (1.71 g,3.69 mmol) was added toluene (60 mL), ethanol (30 mL), and an aqueous tripotassium phosphate solution (2.0 mol/L,30 mL) in this order, which were nitrogen-bubbled, under a nitrogen atmosphere, and heated to 60 ℃. After that, pd (PPh) ₃ ) ₄ (0.085 g,0.074 mmol) was stirred with heating at 90℃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 off under reduced pressure. The residue was subjected to silica gel column chromatography to obtain compound (H-3) (yield 3.21g, yield 63%).

[ evaluation of Compounds ]

The following evaluations were performed on the following aromatic compounds of the present invention, namely, the compound (H-1), the compound (H-2) and the compound (H-3), and the comparative compound (C-1) and the comparative compound (C-2), which were synthesized in Synthesis examples I-1 to I-3.

[ 65]

Evaluation of Tg, ip, ea, eg

The glass transition temperature (Tg) of each compound was evaluated by differential scanning calorimetry (differential scanning calorimetry, DSC).

The ionization energy (Ip) of each compound was evaluated by a photoelectron spectroscopy.

The electron affinity (Ea) of each compound was calculated by subtracting Ip from the band gap (Eg) calculated from the absorption end of the absorption spectrum.

The results are shown in Table 1.

TABLE 1

< evaluation of solvent solubility >

As an evaluation of the solubility of each compound with respect to cyclohexylbenzene (cyclohexyl benzene, CHB), about 1 mL-2 mL of a cyclohexylbenzene solution (concentration of each compound: 2.0 mass%) was prepared, and whether each compound was dissolved in the solution was evaluated.

The compound (H-1), the compound (H-2) and the compound (H-3) of the present invention have a solubility of 2.0 mass% or more with respect to CHB, and exhibit good solubility, similarly to the comparative compound (C-1) and the comparative compound (C-2).

< evaluation of solvent resistance >

The solvent resistance of the obtained compound after film formation was evaluated as follows.

First, a solution in which a compound to be tested was dissolved in toluene at 1.5 mass% was prepared.

The solution was spin-coated onto 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 to be tested. The film thickness of each compound film formed is shown in table 2.

Then, a substrate on which a compound film was formed was set on a spin coater, 150. Mu.L of a test solvent was dropped onto the substrate, and the substrate was left to stand for 60 seconds after the dropping, to thereby conduct a solvent resistance test. As test solvent, 1-butanol was used.

Thereafter, the substrate was rotated at 1500rpm for 30 seconds, followed by rotation at 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 variation before and after the solvent resistance test was estimated from the respective film thickness differences.

The solvent resistance of the compound after film formation was evaluated on the basis of the following criteria.

O: no decrease in film thickness was found.

X: it was found that the film thickness was reduced in the range of 5nm or more and less than 15 nm.

X×: the film dissolves and disappears.

The results of the solvent resistance test are shown in table 2.

TABLE 2

From the above results, it is clear that the aromatic compound of the present invention is excellent in heat resistance and solvent solubility, and also excellent in solvent resistance to alcohol solvents and large in band gap in the film.

Element example II-1

An organic electroluminescent device was fabricated by the following method.

An Indium Tin Oxide (ITO) transparent conductive film was deposited to a thickness of 50nm on a glass substrate (manufactured by Ji Aoma technology (Geomatec)) and sputtered to a film product, which was patterned into stripes 2mm wide using a usual photolithography technique and hydrochloric acid etching, thereby forming 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, 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, thereby forming a uniform thin film having a film thickness of 40nm 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 functioning 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 2.3% by weight of the compound (H-1) of the present invention synthesized in synthesis example I-1, 1.15% by weight of the compound (EH-1), 1.15% by weight of the compound (EH-2) and 1.4% by weight of the compound (D-1) in cyclohexylbenzene.

[ 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 used 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 film thickness ratio was co-deposited on the light-emitting layer to form an electron transport layer having a film thickness of 30 nm.

[ 69]

Then, as a mask for cathode vapor deposition, a 2mm wide striped shadow mask (shadow mask) was closely attached to the substrate so as to be orthogonal 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.

Element example II-2

An organic electroluminescent device was produced in the same manner as in element example II-1, except that the compound (H-2) of the present invention synthesized in Synthesis example I-2 was used as a material of the light-emitting layer instead of the compound (H-1).

Element examples II-3

An organic electroluminescent device was produced in the same manner as in element example II-1, except that the compound (H-3) of the present invention synthesized in Synthesis example I-3 was used as a material of the light-emitting layer instead of the compound (H-1).

Element comparative example II-1

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

[ evaluation of element ]

The organic electroluminescent elements obtained in element examples II-1 to II-3 and element comparative example II-1 were subjected to a reaction of 1,000cd/m ² The current efficiency (cd/a) and the 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 values of element examples II-1 to II-3 represent relative values in which the value of element comparative example II-1 was set to 1.

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

TABLE 3

	Current efficiency	External quantum efficiency	LT95
				Element example II-1	1.00	1.01	1.46
Element example II-2	1.00	1.02	1.57
				Element example II-3	1.02	1.02	1.44
Element comparative example II-1	1.00	1.00	1.00

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.

Japanese patent applications 2021-094593 and 2021, 9 and 13, filed on 6/4/2021, are incorporated herein by reference in their entirety.

Claims

1. An organic electroluminescent element having an anode and a cathode on a substrate, and an organic layer between the anode and the cathode, characterized in that,

the organic layer has a layer containing an aromatic compound represented by the following formula (1),

in the formula (1), the components are as follows,

Ar ¹ 、Ar ² and Ar is a group ⁵ Is represented by the following formula (2) or the following formula (3);

L ¹ ～L ⁵ each independently is a divalent aromatic hydrocarbon group having 6 to 60 carbon atoms which may have a substituent;

r each independently represents an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyl group, a halogen atom, a haloalkyl group, an alkylthio group, an arylthio group, a silyl group, a siloxy group, an aralkyl group or an aromatic hydrocarbon group;

m1, m2 and m5 each independently represent an integer of 0 to 5;

m3 and m4 each independently represent an integer of 1 to 5;

n represents an integer of 0 to 10;

a1 and a2 each independently represent an integer of 0 to 3;

a3 represents an integer of 0 to 4;

a4 represents an integer of 0 or 1;

wherein a4 is 0 in the case where a3 is 4;

in Ar ¹ ～Ar ⁵ A monovalent aromatic hydrocarbon group having 6 to 60 carbon atoms, and L ¹ ～L ⁵ A divalent aromatic hydrocarbon group having 6 to 60 carbon atoms, each of which is independently an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an acyl group, a halogen atom, a haloalkyl group, an alkylthio group, an arylthio group, a silyl group, a siloxy group, an aralkyl group or an aromatic hydrocarbon group;

in the formula (1), ar ¹ -(L ¹ ) _m1 -、Ar ² -(L ² ) _m2 -、Ar ³ -(L ³ ) _m3 -、Ar ⁴ -(L ⁴ ) _m4 -none are hydrogen atoms;

in the formula (2) or the formula (3),

asterisks indicate the bond with formula (1);

2. The organic electroluminescent element according to claim 1, wherein Ar ¹ And Ar is a group ² Ar when n is 1 or more ⁵ Or at least one Ar when n is 2 or more ⁵ Represented by the formula (2) or the formula (3).

3. The organic electroluminescent element according to claim 1 or claim 2, wherein L ¹ ～L ⁵ Each independently represents a phenylene group having a substituent or not, or a group obtained by linking two or more phenylene groups having a substituent or not.

4. The organic electroluminescent element according to claim 3, wherein L ¹ ～L ⁵ Each independently is a 1, 3-phenylene group with or without substituents.

5. The organic electroluminescent element according to any one of claims 1 to 4, wherein the molecular weight of the aromatic compound is 1200 or more.

6. The organic electroluminescent element according to any one of claims 1 to 5, wherein the layer containing the aromatic compound is a light-emitting layer.

7. A display device having the organic electroluminescent element according to any one of claims 1 to 6.

8. A lighting device having the organic electroluminescent element as claimed in any one of claims 1 to 6.

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

in the formula (1), the components are as follows,

r each independently represents an alkyl group, an alkenyl group, an aryloxy group, an alkoxycarbonyl group, an acyl group, a halogen atom, a haloalkyl group, a silyl group, a siloxy group, an aralkyl group or an aromatic hydrocarbon group;

m1, m2 and m5 each independently represent an integer of 0 to 5;

m3 and m4 each independently represent an integer of 1 to 5;

n represents an integer of 0 to 10;

a1 and a2 each independently represent an integer of 0 to 3;

a3 represents an integer of 0 to 4;

a4 represents an integer of 0 or 1;

wherein a4 is 0 in the case where a3 is 4;

in Ar ¹ ～Ar ⁵ A monovalent aromatic hydrocarbon group having 6 to 60 carbon atoms, and L ¹ ～L ⁵ A divalent aromatic hydrocarbon group having 6 to 60 carbon atoms, each of which is independently an alkyl group, an alkenyl group, an aryloxy group, an alkoxycarbonyl group, an acyl group, a halogen atom, a haloalkyl group, a silyl group, a siloxy group, an aralkyl group or an aromatic hydrocarbon group;

in the formula (2) or the formula (3),

asterisks indicate the bond with formula (1);

R ¹ ～R ²⁶ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an aryloxy group, an alkoxycarbonyl group, an acyl group, a halogen atom, a haloalkyl group, a silane group, a siloxane group, an aralkyl group, or an aromatic hydrocarbon group.

10. The aromatic compound of claim 9, wherein a1, a2, and a4 are 0.

11. The aromatic compound according to claim 9, wherein a4 is 1 and a3 is an integer of 0 to 3.

12. The aromatic compound of claim 11, wherein a1, a2 and a3 are the same.

13. The aromatic compound according to any one of claims 9 to 12, wherein Ar ¹ And Ar is a group ² Ar when n is 1 or more ⁵ Or at least one Ar when n is 2 or more ⁵ Represented by the formula (2) or the formula (3).

14. The aromatic compound according to any one of claims 9 to 13, wherein L ¹ ～L ⁵ Each independently represents a phenylene group having a substituent or not, or a group obtained by linking two or more phenylene groups having a substituent or not.

15. The aromatic compound of claim 14, wherein L ¹ ～L ⁵ Each independently is a1, 3-phenylene group with or without substituents.

16. The aromatic compound according to any one of claims 9 to 15, wherein the molecular weight is 1200 or more.

17. A composition comprising the aromatic compound according to any one of claims 9 to 16 and an organic solvent.

18. The composition of claim 17, further comprising a phosphorescent light emitting material and a charge transporting material.

19. The composition of claim 18, wherein the charge transport material comprises a compound represented by the following formula (250) and/or a compound represented by the following formula (240),

in the formula (250), the amino acid sequence of the formula (250),

each W independently represents CH or N, at least one W being N;

Xa ¹ 、Ya ¹ and Za ¹ Each independently represents a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms with or without a substituent, or a divalent aromatic heterocyclic group having 3 to 30 carbon atoms with or without a substituent;

Xa ² 、Ya ² and Za ² Each independently represents a hydrogen atom, a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms with or without a substituent, or a monovalent aromatic heterocyclic group having 3 to 30 carbon atoms with or without a substituent;

g11, h11 and j11 each independently represent an integer of 0 to 6,

at least one of g11, h11 and j11 is an integer of 1 or more;

in the case where g11 is 2 or more, a plurality of Xas are present ¹ Can be in phaseAnd may be different from the above;

when h11 is 2 or more, a plurality of Ya are present ¹ May be the same or different;

when j11 is 2 or more, a plurality of Za are present ¹ May be the same or different;

R ³¹ Represents a hydrogen atom or a substituent, four R ³¹ May be the same or different;

wherein, when g11, h11 or j11 is 0, xa corresponds to each ² 、Ya ² 、Za ² Is not a hydrogen atom;

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 and having or not having a substituent;

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

20. The composition of claim 19, wherein at least two of the three W in formula (250) are N.

21. The composition of claim 20, wherein all of the W in formula (250) are N.

22. The composition of claim 19, wherein Ar in the formula (240) ⁶¹¹ And Ar is a group 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.

23. The composition of claim 19, wherein R in the formula (240) ⁶¹¹ And R is ⁶¹² Each independently represents a monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms and having or not having a substituent.

24. The composition of claim 19, wherein n in the formula (240) ⁶¹¹ And n ⁶¹² Each independently is 0 or 1.

25. A film forming method comprising the step of forming a film of the composition according to any one of claims 17 to 24 by a wet film forming method.

26. A method of manufacturing an organic electroluminescent element having an anode and a cathode over a substrate with an organic layer therebetween,

the method for producing an organic electroluminescent element, comprising the step of forming the organic layer by a wet film formation method using the composition according to any one of claims 17 to 24.

27. The method for manufacturing an organic electroluminescent element according to claim 26, wherein the organic layer is a light-emitting layer.

28. A method for manufacturing an organic electroluminescent element, characterized in that the organic electroluminescent element has an anode and a cathode on a substrate with an organic layer therebetween,

in the method for manufacturing the organic electroluminescent element, the organic layer comprises a light-emitting layer and an electron transport layer,

Comprising 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 17 to 24; and

29. The method for manufacturing an organic electroluminescent element according to claim 28, wherein the solvent contained in the composition for forming an electron transport layer is an alcohol-based solvent.

30. An organic electroluminescent element characterized by having an anode and a cathode on a substrate, an organic layer between the anode and the cathode,

the organic layer comprises a light-emitting layer,

the light-emitting layer comprising the aromatic compound according to any one of claim 9 to claim 16, a phosphorescent light-emitting material and a charge transport material,

the charge transport material comprises a compound represented by the following formula (250) and/or a compound represented by the following formula (240),

in the formula (250), the amino acid sequence of the formula (250),

each W independently represents CH or N, at least one W being N;

g11, h11 and j11 each independently represent an integer of 0 to 6,

at least one of g11, h11 and j11 is an integer of 1 or more;

in the case where g11 is 2 or more, a plurality of Xas are present ¹ May be the same or different;

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

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

31. The organic electroluminescent element according to claim 30, wherein at least two of three W in the formula (250) are N.

32. The organic electroluminescent element according to claim 31, wherein all of W in the formula (250) are N.