WO2021166900A1

WO2021166900A1 - Organic electroluminescent element, organic el display device, and organic el lighting

Info

Publication number: WO2021166900A1
Application number: PCT/JP2021/005683
Authority: WO
Inventors: 良子梶山; 延軍李; 中井　敏光; 一毅岡部
Original assignee: 三菱ケミカル株式会社
Priority date: 2020-02-20
Filing date: 2021-02-16
Publication date: 2021-08-26
Also published as: JPWO2021166900A1; KR20220143826A; CN115136339A; TW202136369A

Abstract

This organic electroluminescent element comprises, on a substrate, a positive electrode, a negative electrode, and an organic layer between the positive electrode and the negative electrode. The organic layer has a hole transport layer, and a light-emitting layer adjacent to the hole transport layer. At least one of materials contained in the hole transport layer and at least one of materials contained in the light-emitting layer both have the same partial structure A represented by formula (31). The ring HA is an aromatic heterocyclic ring, which may have a substituent, of a single ring or 2-6 fused rings. Ar⁰ is an aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a monovalent group obtained by linking a plurality of at least two groups selected from an aromatic hydrocarbon group which may have a substituent and an aromatic heterocyclic group which may have a substituent. n1 is 0 or an integer equal to or less than the number in which Ar⁰ can be substituted for the ring HA.

Description

Organic electroluminescent element, organic EL display device and organic EL lighting

The present invention relates to an organic electroluminescent element, an organic EL display device having the organic electroluminescent element, and organic EL lighting.

Examples of the method for forming the organic layer in the organic electroluminescent device include a vacuum vapor deposition method and a wet film deposition method. Since the vacuum vapor deposition method is easy to stack, it has the advantages of improving charge injection from the anode and / or cathode and facilitating containment of excitons in the light emitting layer. On the other hand, the wet film forming method does not require a vacuum process, it is easy to increase the area, and by using a coating liquid in which a plurality of materials having various functions are mixed, a plurality of materials having various functions can be easily obtained. There are advantages such as being able to form a layer containing the above materials.
However, since the wet film deposition method is difficult to stack, the drive stability is inferior to that of the device by the vacuum vapor deposition method, and the drive stability has not reached the practical level except for a part.

A charge-transporting polymer having a crosslinkable group is desired and is being developed for laminating by a wet film formation method. For example, Patent Document 1 discloses an organic EL produced by laminating a plurality of layers by a wet film forming method.

International Publication No. 2013/080696

However, the stacking by the conventional wet film formation method has a problem in the hole transport efficiency between the laminated layers, for example, the light emitting layer and the hole transport layer.

Patent Document 1 discloses that the host compound of the light emitting layer should have a structure common to that of the compound constituting the hole transport layer from the viewpoint of charge transport. However, the disclosed structure is only a small part, and it is not clear what other structure can exert this effect. In addition, there is still room for study on the effects of the organic electroluminescent device as a whole, such as brightness and drive life.

An object of the present invention is to provide an organic electroluminescent device having high brightness and long drive life.

In an organic electroluminescent element having an anode, a cathode, and an organic layer between the anode and the cathode on a substrate, the present inventor has a light emitting layer in which the organic layer is adjacent to a hole transport layer and a hole transport layer. A specific structure containing an aromatic heterocycle having a monocyclic ring or a 2 to 6 fused ring, wherein both the material contained in the hole transport layer and the material contained in the light emitting layer have an electron attracting property. It has been found that the performance of the organic electroluminescent element is improved by including the material having the above as a partial structure.
The gist of the present invention is as follows [1] to [19].

[1] An organic electroluminescent device having an anode, a cathode, and an organic layer between the anode and the cathode on a substrate, wherein the organic layer is adjacent to a hole transport layer and the hole transport layer. At least one of the materials contained in the hole transport layer and at least one of the materials contained in the light emitting layer both have the same partial structure A represented by the following formula (31). An organic electroluminescent element having.

(In equation (31)
Ring HA represents an aromatic heterocycle of a monocyclic ring or a 2-6 condensed ring which may have a substituent.
The benzene ring in formula (31) may have a substituent.
Ar ⁰ is an aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or an aromatic hydrocarbon group which may have a substituent and Represents a monovalent group in which a plurality of two or more groups selected from aromatic heterocyclic groups which may have a substituent are linked.
n1 represents an integer less than or equal to the number in ^{which Ar 0} can be replaced with 0 or ring HA.
When n1 is 2 or more, a plurality of Ar ^0s may be the same or different. )

[2] The organic according to [1], wherein at least one of the material having the partial structure A contained in the hole transport layer and the material having the partial structure A contained in the light emitting layer has two or more partial structures A. Electric field light emitting element.

[3] The organic electric field according to [1] or [2], wherein the partial structure A represented by the formula (31) is a structure represented by any of the following formulas (33) to (35). Light emitting element.

(In formula (33) to formula (35),
Ar ⁰ and n1 are synonymous with those in the equation (31). The benzene ring in the formulas (33) to (35) may have a substituent.
X and Y each independently represent a C atom or an N atom.
When X and Y are C atoms, Ar ⁰ may be bonded. )

[4] The organic electroluminescent device according to [3], wherein X and Y are N atoms in the partial structure represented by the above formula (35).

[5] Described in any one of [1] to [4], wherein the material having the partial structure A contained in the hole transport layer is a polymer compound having a repeating unit represented by the following formula (1). Organic electric field light emitting element.

(In equation (1),
A represents a partial structure A.
G represents an aromatic hydrocarbon group that may have a substituent, or an N atom.
Ar ² may have a divalent aromatic hydrocarbon group which may have a substituent, a divalent aromatic heterocyclic group which may have a substituent, or a substituent. A divalent group in which a plurality of two or more groups selected from a good divalent aromatic hydrocarbon group and a divalent aromatic heterocyclic group which may have a substituent are directly or via a linking group are linked. Represents.
Ar ²⁰ is directly bonded, has a divalent aromatic hydrocarbon group which may have a substituent, or a plurality of divalent aromatic hydrocarbon groups which may have a substituent are linked. Represents a divalent group. )

[6] The G is a group consisting of any of a benzene ring which may have a substituent, a fluorene ring which may have a substituent, and a spirofluorene ring which may have a substituent. The organic electric field light emitting element according to [5].

[7] The organic electroluminescent device according to [5], wherein G is an N atom.

[8] The organic electric field emission according to [7], wherein the repeating unit represented by the formula (1) is a repeating unit represented by any of the following formulas (2) -1 to (2) -3. element.

(In equation (2) -1 to equation (2) -3,
A is synonymous with A in the above formula (1).
Q represents -C (R ⁵ ) (R ⁶ )-, -N (R ⁷ )-or -C (R ¹¹ ) (R ¹² ) -C (R ¹³ ) (R ¹⁴ )-.
R ¹ to R ⁴ each independently represent an alkyl group which may have a substituent, an alkoxy group which may have a substituent, or an aralkyl group which may have a substituent.
R ⁵ to R ⁷ and R ¹¹ to R ¹⁴ may independently have an alkyl group which may have a substituent, an alkoxy group which may have a substituent, and a substituent. Represents an aromatic hydrocarbon group which may have an aralkyl group or a substituent.
a and b are independently integers of 0 to 4.
c1 to c5 are independently integers of 0 to 3.
However, at least one of c3 and c5 is 1 or more.
d1 to d4 are independently integers of 1 to 4.
When ^{there are a plurality of R 1} , R ² , R ³ , and R ⁴ in the repeating unit, R ¹ , R ² , R ³ , and R ⁴ may be the same or different. )

[9] The organic electroluminescent device according to any one of [5] to [8], ^{wherein -Ar 20-} A in the formula (1) is represented by the following formula (15).

(In equation (15),
X and Y each independently represent a C atom or an N atom. The ring having X, Y and N corresponds to the ring HA in the formula (31).
Ar ¹ is a divalent aromatic hydrocarbon group which may have a substituent or a divalent aromatic hydrocarbon group in which two or more divalent aromatic hydrocarbon groups which may have a substituent are linked. Represents a group.
Ar ³ and Ar ⁴ may independently have an aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a substituent. Represents a monovalent group in which a plurality of two or more groups selected from a good aromatic hydrocarbon group and an aromatic heterocyclic group which may have a substituent are linked.
However, ^{in at least one of Ar 1} , Ar ³ , and Ar ⁴ , the structure bonded to the ring HA is a benzene ring.
* Represents the binding site with G. )

[10] The organic electroluminescent device according to [9], ^{wherein -Ar 20-} A in the above formula (1) is represented by the following formula (16).

(In equation (16),
X, Y, and * are synonymous with those in the above equation (15).
The ring having X, Y and N corresponds to ring HA as in the formula (15).
Ar ¹ 'is the direct bond or the formula (15) represents the residue of a case structure of bonding to the ring of HA Ar ¹ is a benzene ring.
Ar ³ ', Ar ^4', in the hydrogen atom or each said formula (15) ^represents the residue of a case structure that binds to Ar 3, Ar ⁴ rings HA is a benzene ring. )

[11] The organic electric field light emitting device according to any one of [5] to [10], wherein the material having the partial structure A contained in the hole transport layer further has a repeating unit represented by the following formula (3). ..

(In equation (3),
Ar ¹³ represents an aromatic hydrocarbon group which does not contain a partial structure A and may have a substituent or an aromatic heterocyclic group which may have a substituent.
Ar ¹⁴ may have a divalent aromatic hydrocarbon group which may have a substituent, a divalent aromatic heterocyclic group which may have a substituent, or a substituent. A divalent group in which a plurality of two or more groups selected from a good divalent aromatic hydrocarbon group and a divalent aromatic heterocyclic group which may have a substituent are directly or via a linking group are linked. Represents. )

[12] The light emitting layer contains a low molecular weight compound having the partial structure A, and the low molecular weight compound is a compound having a molecular weight of 5,000 or less represented by any of the following formulas (10) to (12). The organic electric field light emitting element according to [1] to [11].

(In equations (10) to (12),
A is the partial structure A.
B represents a single bond or any substructure.
na, nb and nc represent integers from 1 to 5.
When na, nb, and nc are 2 or more, the plurality of A, B, and AB may be the same or different. )

[13] The organic electroluminescent device according to [12], wherein the small molecule compound represented by the formula (10) is represented by the following formula (10A).

(In formula (10A),
HA represents any of the trivalent aromatic heterocyclic groups represented by the following structural formulas (10A-a), (10A-b) and (10A-c).
Xa ¹ , Ya ¹ , and Za ¹ each independently have a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms, which may have a substituent, or a carbon which may have a substituent. Represents a divalent aromatic heterocyclic group of numbers 3 to 30.
Each of Xa ² , Ya ² and Za ² independently has a hydrogen atom, an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or a carbon number which may have a substituent. Represents 3 to 30 aromatic heterocyclic groups.
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.
When g11, h11, and j11 are 2 or more, Xa ¹ , Ya ¹ , and Za ¹ may be the same or different.
R ³¹ represents a hydrogen atom or a substituent, and the four R ^31s may be the same or different. )

(In formulas (10A-a) to (10A-c), * represents the bonding position.)

[14] The organic electroluminescent device according to [13], wherein the small molecule compound represented by the formula (10) is represented by the following formulas (10A-1) to (10A-3).

(In formulas (10A-1) to (10A-3),
Xa ¹ , Ya ¹ , Za ¹ , Xa ² , Ya ² , and Za ² are synonymous with those in equation (10).
R ³³ represents a hydrogen atom or a substituent, and a plurality of R ³³ may be the same or different.
g11', h11' and j11'independently represent integers from 0 to 5.
When g11', h11', and j11' are 2 or more, the plurality of Xa ¹ , Ya ¹ , and Za ¹ may be the same or different. )

[15] The organic electroluminescent device according to [12], wherein the small molecule compound represented by the formula (10) is represented by the following formula (10B).

(In formula (10B),
A has the same meaning as in the above formula (10).
Xb ¹ , Yb ¹ , and Zb ¹ each independently may have a substituent or a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms, or a carbon which may have a substituent. Represents a divalent aromatic heterocyclic group of numbers 3 to 30.
p12, q12, and r12 each independently represent an integer of 0 to 6.
When p12, q12, and r12 are 2 or more, the plurality of Xb ¹ , Yb ¹ , and Zb ¹ may be the same or different.
q13 and r13 independently represent 0 or 1, respectively.
However, q12 and q13 are not 0 at the same time, and r12 and r13 are not 0 at the same time.
^{Yb 2} when q13 is 0 ^{and Zb 2} when r13 is 0 independently have a hydrogen atom, an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or a substituent. Represents an aromatic heterocyclic group having 3 to 30 carbon atoms which may have.
When q13 is 1, Yb ² is a direct bond.
When r13 is 1, Zb ² is a direct bond. )

[16] The organic electroluminescent device according to [15], wherein the small molecule compound represented by the formula (10) is represented by the following formula (10B-1).

(In equation (10B-1),
A, Xb ¹ , Yb ¹ , Zb ¹ , Yb ² , Zb ² , q13, and r13 are synonymous with those in the above formula (10B).
p12', q12' and r12'independently represent integers from 0 to 5.
When p12', q12', and r12'are 2 or more, a plurality of Xb ¹ , Yb ¹ , and Zb ¹ may be the same or different.
q15 and r15 are 4 or 5 independently, respectively.
R ³³ is a hydrogen atom or a substituent.
^{The plurality of R 33s} in the formula (10B-1) may be the same or different. )

[17] The organic electroluminescent device according to [12], wherein the small molecule compound represented by the formula (12) is represented by the following formula (12A).

(In formula (12A),
Rings HA and Ar ⁰ are synonymous with those in the above formula (31).
nc has the same meaning as in the above formula (12).
Each of Xc ¹ and Yc ¹ independently has a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or 3 to 30 carbon atoms which may have a substituent. Represents a divalent aromatic heterocyclic group of.
Each of Xc ² and Yc ² has a hydrogen atom, an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or an aromatic hydrocarbon group having 3 to 30 carbon atoms which may have a substituent. Represents an aromatic heterocyclic group.
Each of s11 and t11 independently represents an integer of 0 to 6.
When s11 and t11 are 2 or more, the plurality of Xc ¹ and Yc ¹ may be the same or different.
R ³¹ represents a hydrogen atom or a substituent.
u11 is the number of substitutable substituents ^{R 31.}
u12 is a number in which the substituent ^{Ar 0 can be substituted.}
If u11 is 2 or more, plural R ³¹ may be different even in the same. )

[18] An organic EL display device including the organic electroluminescent device according to any one of [1] to [17].

[19] An organic EL lighting provided with the organic electroluminescent device according to any one of [1] to [17].

According to the present invention, it is possible to provide an organic electroluminescent device having high brightness and a long drive life.

The reason why the organic electroluminescent device according to the embodiment of the present invention exerts the above effect is not clear, but the following can be considered.
The organic electroluminescent element of the present invention has a specific structure including an aromatic heterocyclic group having a monocyclic ring or a 2 to 6 fused ring, which is a structure having electron attraction (in the present invention, "partial structure A". (Hereinafter referred to as "partial structure A-containing material") is included in both the hole transport layer and the light emitting layer. In the partial structure A, LUMO is easily localized and the electronic durability is high. Therefore, it is considered that the deterioration of the hole transport layer due to the electrons leaking from the light emitting layer to the hole transport layer is suppressed. Further, the electrons localized near the interface of the light emitting layer of the hole transport layer are considered to contribute to recombination in the light emitting layer, and the luminous efficiency is considered to be improved. Furthermore, it is considered that the voltage is lowered by efficiently transporting electrons and holes.

It is the schematic of the cross section which shows the structural example of the organic electroluminescent element of this invention.

Hereinafter, embodiments of an organic electroluminescent device, an organic EL display device having the organic electroluminescent device, and organic EL lighting according to an embodiment of the present invention will be described in detail. The following description is an example (representative example) of an embodiment of the present invention, and the present invention is not specified in these contents unless the gist thereof is exceeded.

[Partial structure A]
The organic electroluminescent device of the present invention is an organic electroluminescent device having an anode, a cathode, and an organic layer between the anode and the cathode on a substrate, and the organic layer is a hole transport layer and the above. It has a light emitting layer adjacent to the hole transport layer, and at least one of the materials contained in the hole transport layer and at least one of the materials contained in the light emitting layer are both represented by the following formula (31). It is characterized by having the same partial structure A.

The partial structure A-containing material contained in the hole transport layer and the partial structure A-containing material contained in the light emitting layer are partial structures A represented by the above formula (31) and have the same partial structure A. This is an important constituent requirement of the present invention. The effect of the present invention can be obtained when the material contained in the hole transport layer and the material contained in the light emitting layer have a common partial structure A represented by the formula (31).

In the present invention, either one or both of the partial structure A-containing material contained in the hole transport layer and the partial structure A-containing material contained in the light emitting layer is a partial structure A-containing material having two or more partial structures A. Is more preferable. Particularly preferably, the partial structure A-containing material contained in the hole transport layer and the partial structure A-containing material contained in the light emitting layer are both partial structure A-containing materials having the same partial structure A. With such a combination, it is expected that the electronic durability of the organic electroluminescent device will be further improved, and the organic electroluminescent device will have high brightness and long life.

Here, the partial structure A-containing material having two or more of the same partial structure A is the same portion in one compound when the partial structure A-containing material having two or more of the same partial structure A is a small molecule compound. It means having two or more structures A. When the partial structure A-containing material having two or more of the same partial structure A is a polymer compound, it means having two or more of the same partial structure A in one repeating unit.

In the present invention, it is also preferable that either or both of the partial structure A-containing material contained in the hole transport layer and the partial structure A-containing material contained in the light emitting layer contains two or more kinds of materials having the partial structure A. .. With such a combination, it is expected that the electronic durability of the organic electroluminescent device will be further improved, and the organic electroluminescent device will have high brightness and long life.

The partial structure A-containing material contained in the hole transport layer is not particularly limited, but is preferably a polymer compound. As the partial structure A-containing material of the polymer compound, a polymer compound having a repeating unit represented by the formula (1) described later can be preferably mentioned.

The partial structure A-containing material contained in the light emitting layer is not particularly limited, but is preferably a small molecule compound.

When the material containing the partial structure A is a polymer compound, the number of the partial structures A contained in the polymer compound is preferably equal to or greater than the number of the partial structures A contained in the repeating unit of the polymer compound. When two partial structures A are present in all the repeating units of the polymer compound, the number of the partial structures A contained in the polymer compound is the repeating unit of the polymer compound × 2. When the polymer compound has a plurality of repeating units, at least one repeating unit may have a partial structure A.

The bonding method of the partial structure A in the partial structure A-containing material contained in the hole transport layer and the partial structure A-containing material contained in the light emitting layer is not particularly limited.

From the viewpoint of charge transportability and electron durability, the partial structure A is represented by the following formula (31) -2 in any of the partial structure A-containing materials of the hole transport layer and the light emitting layer. It is preferable that the benzene ring in A is bonded in the material containing the partial structure A.

(In formula (31) -2, * represents a binding site in the partial structure A-containing material.)

(HA)
In the partial structure A represented by the formula (31), HA represents an aromatic heterocycle which may have a substituent of a monocyclic ring or a 2 to 6 condensed ring. The ring-forming atom of the aromatic heterocycle is preferably any of a nitrogen atom, an oxygen atom, and a sulfur atom in addition to the carbon atom.

As the ring HA, as described later, a dibenzofuran ring, a dibenzothiophene ring, a pyridine ring, a pyrimidine ring, and a 1,3,5-triazine ring are preferable, and a 1,3,5-triazine ring is particularly preferable.

(Ar ⁰ )
In the partial structure A represented by the formula (31), Ar ⁰ is an aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a substituent. It represents a monovalent group in which a plurality of two or more groups selected from an aromatic hydrocarbon group which may have a group and an aromatic heterocyclic group which may have a substituent are linked.

The aromatic hydrocarbon group preferably has 6 or more carbon atoms and 60 or less carbon atoms. Specifically, 6-membered rings such as benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, acenaphthene ring, fluoranthene ring, and fluorene ring. Examples thereof include a monovalent group of a monocyclic ring or a 2 to 5 fused ring, or a monovalent group in which 2 to 10 rings selected from these are linked.
Preferably, it is a monovalent group in which a benzene ring, a naphthalene ring, a fluorene ring or a ring selected from these is linked by 2 to 10.

The aromatic heterocyclic group preferably has 3 or more carbon atoms and 60 or less carbon atoms. Specifically, a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrazole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carbazole ring, a pyroloymidazole ring, a pyrrolopyrazole ring, a pyrrolopyrrole ring, Thienopyrrole ring, thienothiophene ring, flopyrol ring, furan ring, thienofran ring, benzoisoxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring , Cinnoline ring, quinoxaline ring, phenanthridin ring, perimidine ring, quinazolin ring, quinazolinone ring, dibenzofuran ring, dibenzothiophene ring, indolocarbazole ring, phenanthrolin ring, etc. Examples thereof include a monovalent group of a fused ring or a monovalent group in which 2 to 10 of these are linked.
Preferably, a monovalent group of thiophene ring, pyrrole ring, imidazole ring, pyridine ring, pyrimidine ring, triazine ring, quinoline ring, quinazoline ring, carbazole ring, dibenzofuran ring, dibenzothiophene ring, indolocarbazole ring, phenanthroline ring or These are monovalent groups in which 2 to 10 are linked.

The same group is a plurality of monovalent groups in which two or more groups selected from an aromatic hydrocarbon group which may have a substituent and an aromatic heterocyclic group which may have a substituent are linked. It may be a linked group, or a group in which a plurality of different groups are linked may be used. The total number of linked aromatic hydrocarbon groups and / or aromatic heterocyclic groups is preferably 2 to 10.

Ar ⁰ is preferably an aromatic hydrocarbon group which may have a substituent or an aromatic hydrocarbon group substituted with an aromatic heterocyclic group which may have a substituent.

(Preferable Substructure A)
The partial structure A represented by the formula (31) is preferably a structure represented by the following formulas (33) to (35) from the viewpoint of charge transportability and electron durability.

The above formula (35) is preferably represented by the following formula (36) from the viewpoint of charge transportability and electron durability, and more preferably represented by the following formula (37).
In the structure represented by the formula (37), electrons are transferred by the biphenyl structure having high electron resistance, the electron durability of the compound is further improved, and as a result, the drive life of the organic electric field light emitting device is extended. It is thought that.
In the following formula (36), the three benzene rings may have a substituent. In the following formula (37), the four benzene rings may have a substituent.

The structure represented by the above formula (37) is more preferably the structure represented by the following formula (37-2).

“*” And “* 1” in the formula (37-2) are bond positions in the partial structure A-containing material contained in the hole transport layer or the partial structure A-containing material contained in the light emitting layer, or a bond of a substituent. Represents a position. In the formula (37-2), at least "* 1" is the bond position in the partial structure A-containing material contained in the hole transport layer or the partial structure A-containing material contained in the light emitting layer, or the bond position of the substituent. It is preferable that the S1 level and the T1 level are high because the conjugation of the electronically durable biphenyl structure does not spread, the excitons in the light emitting layer are not easily deactivated, and the luminous efficiency is high. From this point of view, it is more preferable that a substance other than a hydrogen atom is bonded to "* 1" and at least one "*".

In the above formulas (35), (36) and (37), X and Y are preferably N atoms. Therefore, the partial structures represented by the above equations (36) and (37) are the structures represented by the following equations (TzP) and (TzP-2) (hereinafter, "partial structure (TzP)" and "partial structure", respectively. It may be referred to as “structure (TzP-2)”), which is preferable from the viewpoint of electrification transportability and stability. The three benzene rings of the partial structure (TzP) and the four benzene rings of the partial structure (TzP-2) may have substituents.

The formula (TzP-2) is more preferably a structure represented by the following formula (TzP-3). The reason why the structure represented by the following formula (TzP-3) is preferable is the same as the reason why the structure represented by the above formula (37-2) is preferable.

“*” And “* 1” in the formula (37-2) are bond positions in the partial structure A-containing material contained in the hole transport layer or the partial structure A-containing material contained in the light emitting layer, or a bond of a substituent. Represents a position.

Further, in the organic electroluminescent device of the present invention, the partial structure A-containing material contained in the hole transport layer and the partial structure A-containing material contained in the light emitting layer have similar skeletons of a common structure as the partial structure A. The higher the degree, the better. A high degree of similarity of the skeletons of the common structure as the partial structure A means that the molecular weights of the matching partial structures A are large.

When the partial structure A represented by the formula (31) is any of the formulas (33) to (35), the partial structure A contained in the hole transport layer or the partial structure contained in the light emitting layer. In the A-containing material, the benzene ring portion of the partial structure A is preferably a bonding position in the partial structure A-containing material contained in the hole transport layer or the partial structure A-containing material contained in the light emitting layer.

Ar0 in the formulas (31), formulas (33) to (35), benzene rings in the formulas (31), formulas (33) to (37), formulas (TzP) and formulas (TzP-2). A good substituent can be selected from the following substituent group Z.

[Substituent group Z]
Examples of the substituent group Z include the following substituents.
For example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, tert-butyl group, n-hexyl group, cyclohexyl group, dodecyl group and the like. , Usually 1 or more, preferably 4 or more, usually 24 or less, preferably 12 or less, linear, branched, or cyclic alkyl groups;
For example, an alkenyl group such as a vinyl group having a carbon number of usually 2 or more, usually 24 or less, preferably 12 or less;
For example, an alkynyl group having a carbon number of usually 2 or more, usually 24 or less, preferably 12 or less, such as an ethynyl group;
For example, an alkoxy group such as a methoxy group or an ethoxy group having a carbon number of usually 1 or more, usually 24 or less, preferably 12 or less;
For example, an aryloxy group or a heteroaryloxy group having a carbon number of usually 4 or more, preferably 5 or more, usually 36 or less, preferably 24, such as a phenoxy group, a naphthoxy group, and a pyridyloxy group;
For example, an alkoxycarbonyl group such as a methoxycarbonyl group or an ethoxycarbonyl group, which usually has 2 or more carbon atoms and usually has 24 or less, preferably 12 or less carbon atoms;
For example, a dialkylamino group such as a dimethylamino group or a diethylamino group, which usually has 2 or more carbon atoms and usually has 24 or less carbon atoms, preferably 12 or less carbon atoms;
For example, a diarylamino group having a carbon number of usually 10 or more, preferably 12 or more, usually 36 or less, preferably 24 or less, such as a diphenylamino group, a ditrilamino group, and an N-carbazolyl group;
For example, an arylalkylamino group having a carbon number of 7 or more, usually 36 or less, preferably 24 or less, such as a phenylmethylamino group;
For example, an acyl group such as an acetyl group or a benzoyl group having a carbon number of usually 2 or more, usually 24 or less, preferably 12 or less;
For example, halogen atoms such as fluorine atoms and chlorine atoms;
For example, a haloalkyl group having usually 1 or more carbon atoms and usually 12 or less, preferably 6 or less carbon atoms, such as a trifluoromethyl group;
For example, an alkylthio group having a carbon number of usually 1 or more, usually 24 or less, preferably 12 or less, such as a methylthio group and an ethylthio group;
For example, an arylthio group or a heteroarylthio group having a carbon number of usually 4 or more, preferably 5 or more, usually 36 or less, preferably 24 or less, such as a phenylthio group, a naphthylthio group, or a pyridylthio group;
For example, a silyl group such as a trimethylsilyl group or a triphenylsilyl group having a carbon number of usually 2 or more, preferably 3 or more, usually 36 or less, preferably 24 or less;
For example, a syroxy group having a carbon number of usually 2 or more, preferably 3 or more, usually 36 or less, preferably 24 or less, such as a trimethylsiloxy group or a triphenylsiloxy group;
Cyano group;
For example, a phenyl group, a naphthyl group, or the like, or a monovalent group in which a plurality of aromatic hydrocarbon rings having the same or different monocyclic or fused rings are linked, usually has 6 or more carbon atoms, and usually 36 or less, preferably 36 or less. Aromatic hydrocarbon groups of 24 or less;
For example, a monovalent group in which a plurality of aromatic heterocycles of the same or different monocyclic or condensed rings are linked, such as a thienyl group, usually has 3 or more carbon atoms, preferably 5 or more carbon atoms, and usually 36 or less, preferably 36 or less carbon atoms. Is 24 or less aromatic heterocyclic groups:
A monovalent aromatic group in which an aromatic hydrocarbon ring and an aromatic heterocyclic group are linked, and when there are a plurality of aromatic hydrocarbon rings or aromatic heterocyclic groups, they may be the same or different. A good, monovalent aromatic group having 8 or more and 36 or less carbon atoms, preferably 24 or less.

Among the above-mentioned substituent group Z, preferably, a monovalent aromatic in which the above-mentioned alkyl group, alkoxy group, aromatic hydrocarbon group, aromatic heterocyclic group, aromatic hydrocarbon ring and aromatic heterocyclic group are linked. It is a group. From the viewpoint of charge transportability, it has no substituent or has a monovalent aromatic group in which an aromatic hydrocarbon group, an aromatic heterocyclic group, an aromatic hydrocarbon ring and an aromatic heterocyclic group are linked. Is even more preferable.

Each substituent of the above-mentioned Substituent Group Z may further have a Substituent. Examples of these substituents include the same substituents as the above-mentioned substituents (substituent group Z). Preferably, it does not have a further substituent, or has an alkyl group having 6 or less carbon atoms, an alkoxy group having 6 or less carbon atoms, a phenyl group, or a crosslinkable group described later as a further substituent. From the viewpoint of charge transportability, it is more preferable to have no additional substituent.

[Polymer compound]
The polymer compound which is a partial structure A-containing material contained in the hole transport layer, which is one form of the present invention, is a polymer compound containing a repeating unit represented by the following formula (1) (hereinafter, “the present invention”. It may be referred to as a "polymer of the embodiment").

(G)
In the repeating unit represented by the formula (1), G represents an aromatic hydrocarbon group which may have a substituent or an N atom. G is a benzene ring, which may have a substituent, from the viewpoint of excellent charge transportability and the separation of LUMO distributed around the partial structure A and HOMO distributed in the main chain. A group consisting of a fluorene ring which may have a group or a spirofluorene ring which may have a substituent is preferable, and the structure shown in the following scheme 1 is more preferable. The following structure may have a substituent. In the figure, "-*" represents a binding site with ^{Ar 20.}

When G is an aromatic hydrocarbon group which may have a substituent, the substituent which may have is the substituent group Z, an aralkyl group having 7 to 40 carbon atoms, or an aralkyl group having 4 to 37 carbon atoms. It is preferable to use any one of the heterocyclic aralkyl groups of the above, or a combination thereof. Among them, in terms of durability, they are the same or different each time they appear, and they are an alkyl group having 1 to 24 carbon atoms, an aromatic group having 7 to 40 carbon atoms, and an aromatic group having a heterocycle having 3 to 37 carbon atoms. It is preferably a group, an arylamino group having 10 to 24 carbon atoms, an aromatic hydrocarbon group having 6 to 36 carbon atoms, or an aromatic heterocyclic group having 3 to 36 carbon atoms, and an alkyl having 1 to 12 carbon atoms. A group, an aralkyl group having 7 to 30 carbon atoms, a heterocyclic aralkyl group having 3 to 27 carbon atoms, an aromatic hydrocarbon group having 6 to 24 carbon atoms, or an aromatic heterocyclic group having 3 to 24 carbon atoms. More preferably, it is an aromatic hydrocarbon group having 6 to 24 carbon atoms.
From the viewpoint of charge transportability, it is the same or different each time it appears, and it is preferably an aromatic hydrocarbon group having 6 to 24 carbon atoms or an aromatic heterocyclic group having 3 to 24 carbon atoms, preferably phenyl. More preferably, it is a group, a naphthyl group, a fluorenyl group, a carbazolyl group, an indolocarbazolyl group, an indenocarbazolyl group, or an indenofluorenyl group. In particular, since the conjugation is broken when bound to the 9-position of spirobifluorene or fluorene, LUMO distributed in the partial structure A and HOMO distributed in the main chain are further localized into fluorenyl groups and indenofluorenyl groups. Is preferable. It is most preferable that G has no substituent because of ease of synthesis and charge transport stability.

G is preferably an N atom (nitrogen atom) from the viewpoint of excellent charge transportability, particularly excellent hole transportability.

(Ar ² , Ar ²⁰ )
In the repeating unit represented by the above formula (1), Ar ² is a divalent aromatic hydrocarbon group which may have a substituent and a divalent aromatic which may have a substituent. A plurality of two or more groups selected from a heterocyclic group or a divalent aromatic hydrocarbon group which may have a substituent and a divalent aromatic heterocyclic group which may have a substituent. Represents a concatenated divalent group.

Ar ²⁰ is directly bonded, has a divalent aromatic hydrocarbon group which may have a substituent, or a plurality of divalent aromatic hydrocarbon groups which may have a substituent are linked. Represents a divalent group.

The aromatic hydrocarbon groups of Ar ² and Ar ²⁰ preferably have 6 or more carbon atoms and 60 or less carbon atoms. Specifically, 6-membered rings such as benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, acenaphthene ring, fluoranthene ring, and fluorene ring. Examples thereof include a divalent group of a monocyclic ring or a 2 to 5 fused ring, or a divalent group in which 2 to 10 rings selected from these are linked.

The aromatic heterocyclic group of Ar ² preferably has 3 or more carbon atoms and 60 or less carbon atoms. Specifically, a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrazole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carbazole ring, a pyrroloymidazole ring, a pyrrolopyrazole ring, a pyrrolopyrrole ring, Thienopyrrole ring, thienothiophene ring, flopyrol ring, furan ring, thienofran ring, benzoisoxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring , Cinnoline ring, quinoxaline ring, phenanthridin ring, perimidine ring, quinazolin ring, quinazolinone ring, etc. Examples thereof include divalent groups in which ~ 10 are linked.

As a divalent group in which a plurality of two or more groups selected from an aromatic hydrocarbon group which may have a substituent of ^{Ar 2 and an aromatic heterocyclic group which may have a substituent are linked.} , The same group may be a group in which a plurality of the same groups are linked, or a group in which a plurality of different groups are linked may be used. When a plurality of groups are linked, it is preferable that the groups are linked by 2 to 10.

Ar ² has a divalent aromatic hydrocarbon group which may have a substituent and a divalent aromatic complex which may have a substituent because of its excellent charge transport property and durability. It is preferable that one or more groups selected from the ring groups are divalent groups bonded directly or via a linking group. If it has a linking group, an oxygen atom or a carbonyl group is preferable.
Since the triplet level can be increased by forming a non-conjugated structure with the aromatic ring, a structure in which the phenylene rings are linked by an oxygen atom or a carbonyl group is preferable.
A benzene ring or a fluorene ring is preferable from the viewpoint of improving charge transportability and excellent stability by expanding the π-conjugated system.
The main chain structure is such that the spread of the π-conjugated system is inhibited, the excited singlet energy level (S ₁ ) and the excited triplet energy level (T ₁ ) are increased, and quenching due to energy transfer from the luminescent exciter is suppressed. Therefore, from the viewpoint of excellent quenching efficiency, a twisted structure that bonds with a fluorene ring and phenylene having an alkyl group is particularly preferable.
Among them, a structure containing a phenylene group having a methyl group is particularly preferable from the viewpoint of difficulty in synthesizing or purifying a monomer intermediate.

Ar ²⁰ has one divalent aromatic hydrocarbon group which may have a direct bond or a substituent from the viewpoint of localizing LUMO distributed in the partial structure A and HOMO distributed in the main chain, respectively. A group having to 9 linked groups is preferable, and a group having 1 to 7 linked divalent aromatic hydrocarbon groups which may have a direct bond or a substituent is more preferable. Among them, a group in which 1 to 5 benzene rings which may have a substituent are linked is more preferable, and 3 benzene rings which may have a substituent are linked, and together with the benzene ring contained in A, Kur A terphenylene group is particularly preferred.
From the viewpoint that the main chain and the partial structure A are unconjugated and the LUMO distributed in the partial structure A and the HOMO distributed in the main chain are more localized, at least one benzene ring linked at the 1st and 3rd positions is provided. It is preferable to include it, and it is more preferable to include 2 or more.
In the case of a group in which a plurality of divalent aromatic hydrocarbon groups which may have a substituent are linked, it is preferable that all of them are directly bonded and linked from the viewpoint of charge transportability or durability.

When G is a nitrogen atom, the hole transportability is improved. Therefore, ^{as the partial structure of Ar 2} directly bonded to G, an aromatic hydrocarbon group which may have a substituent is preferable, and the substituent is used. A phenylene group which may have a substituent or a fluorenylene group which may have a substituent is more preferable, and a phenylene group which may have a substituent is particularly preferable. A benzene ring or a fluorene ring is preferably bonded to the benzene ring directly bonded to G, which is a nitrogen atom, and one or more phenylene groups are further between the benzene ring directly bonded to the nitrogen atom and the fluorene ring. A structure in which fluorene is connected is also preferable.

The ^{substituents that Ar 2} and Ar ²⁰ may have in cases other than direct bonding are the same as the substituents that may be possessed when G is an aromatic hydrocarbon group. From the viewpoint of ease of synthesis and charge transport stability, ^{it is most preferable that Ar 2} and Ar ²⁰ do not have a substituent.

^{From the viewpoint of excellent electronic durability, -Ar 20-} A in the repeating unit represented by the above formula (1) is preferably represented by the following formula (15), and is represented by the formula (16) described later. It is more preferable to be done.

(In equation (15),
X and Y each independently represent a C atom or an N atom. The ring having X, Y and N corresponds to the ring HA in the formula (31).
Ar ¹ is a divalent aromatic hydrocarbon group which may have a substituent or a divalent group in which two or more divalent aromatic hydrocarbon groups which may have a substituent are linked. show.
Ar ³ and Ar ⁴ may independently have an aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a substituent. Represents a monovalent group in which a plurality of two or more groups selected from a good aromatic hydrocarbon group and an aromatic heterocyclic group which may have a substituent are linked.
However, ^{in at least one of Ar 1} , Ar ³ , and Ar ⁴ , the structure bonded to the ring HA is a benzene ring.
* Represents the binding site with G. )

(Ar ¹ )
Ar ¹ is a divalent aromatic hydrocarbon group which may have a substituent or a divalent aromatic hydrocarbon group in which two or more divalent aromatic hydrocarbon groups which may have a substituent are linked. Represents a group. The aromatic hydrocarbon preferably has 6 or more carbon atoms and 60 or less carbon atoms. Specifically, 6-membered rings such as benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, acenaphthene ring, fluoranthene ring, and fluorene ring. A divalent group of a monocyclic ring or a 2 to 5 fused ring, or a divalent group in which 2 to 10 rings selected from these are linked is preferable.
As the ^{substituent that Ar 1} may have, any one of the substituent group Z or a combination thereof can be used. From the viewpoint of durability and charge transportability, it is preferable to select from the same substituents that ^{Ar 2 may have.}

(Ar ³ , Ar ⁴ )
Ar ³ and Ar ⁴ may independently have an aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a substituent. A monovalent group in which a plurality of two or more groups selected from a good aromatic hydrocarbon group and an aromatic heterocyclic group which may have a substituent are linked is preferable.

The aromatic hydrocarbon group preferably has 6 or more carbon atoms and 60 or less carbon atoms. Specifically, 6-membered rings such as benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, acenaphthene ring, fluoranthene ring, and fluorene ring. A monovalent group of a monocyclic ring or a 2 to 5 fused ring, or a monovalent group in which 2 to 10 rings selected from these are linked is preferable.

The aromatic heterocyclic group preferably has 3 or more carbon atoms and 60 or less carbon atoms. Specifically, a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrazole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carbazole ring, a pyrroloymidazole ring, a pyrrolopyrazole ring, a pyrrolopyrrole ring, Thienopyrrole ring, thienothiophene ring, flopyrol ring, furan ring, thienofran ring, benzoisoxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring , Cinnoline ring, quinoxaline ring, phenanthridin ring, perimidine ring, quinazolin ring, quinazolinone ring, etc. Examples include to 10 linked monovalent groups.

As a monovalent group in which a plurality of two or more groups selected from an aromatic hydrocarbon group and an aromatic heterocyclic group are linked, 2 to 10 structures selected from the aromatic hydrocarbon and the aromatic heterocyclic ring are linked. A monovalent group is preferred.

From the viewpoint of distributing LUMO, Ar ³ and Ar ⁴ are independently a-1 to a-4, b-1 to b-9, c-1 to c-5, and d-1 shown in Scheme 2 below. It is preferable to have a structure selected from ~ d-17 and e-1 to e-4.
Furthermore, from the viewpoint of promoting the spread of LUMO of the molecule by having an electron-attracting group, a-1 to a-4, b-1 to b-9, c-1 to c-5, d-1 to A structure selected from d-13 and e-1 to e-4 is preferable.
It is selected from a-1 to a-4, d-1 to d-13, and e-1 to e-4 from the viewpoint of the effect of confining excitons formed in the light emitting layer, which has a higher triplet level. The structure is preferred.
Structures selected from d-1 to d-13 and e-1 to e-4 are more preferred in order to prevent molecular aggregation.
The structure of the benzene ring of ^{Ar 3} = Ar ⁴ = d-3 is particularly preferable from the viewpoint of easy synthesis and excellent stability.
These structures may have substituents. In the figure, "-*" represents a binding site with ring HA. When there are a plurality of "-*", one of them represents a site that binds to the ring HA.

^{It is preferable that R 3A} and R ^3B of the above scheme 2 are linear, branched or cyclic alkyl groups which may independently have a substituent. The number of carbon atoms of the alkyl group is not particularly limited, but in order to maintain the solubility of the polymer, the number of carbon atoms is preferably 1 or more and 6 or less, more preferably 3 or less, and further preferably a methyl group or an ethyl group. ..

R ^3A and R ^3B may be the same or different. ^{It is preferable that all R 3A} and R ^3B have the same group because the charge can be uniformly distributed around the nitrogen atom and the synthesis is easy.

As the ^{substituents that Ar 3} and Ar ⁴ may have, any one of the substituent group Z or a combination thereof can be used. From the viewpoint of durability and charge transportability, it is preferable to select from the same substituents that ^{Ar 2 may have.}

(In equation (16),
X, Y, and * are synonymous with those in the above equation (15).
The ring having X, Y and N corresponds to ring HA as in the formula (15).
Ar 1 ^'is the direct bond or the formula (15) represents a residue when X corresponding to rings HA of Ar ^1, a structure bonding to the ring with Y and N is a benzene ring.
Ar ³ ', Ar ^4', in the hydrogen atom or each said formula ^(15), when X corresponding to rings HA of Ar 3, Ar ^4, a structure bonding to the ring with Y and N is a benzene ring Represents a residue. )

[Preferable repeating unit structure]
The repeating unit represented by the formula (1) is preferably a repeating unit represented by any of the following formulas (2) -1 to (2) -3.

(R ¹ and R ² )
^{R 1} and R ² in the repeating unit represented by the above formulas (2) -1 to (2) -3 each independently have an alkyl group and a substituent which may have a substituent. It is an alkoxy group which may be present, or an aralkyl group which may have a substituent. R ¹ and R ² are preferably linear, branched or cyclic alkyl groups, each of which may independently have a substituent. The number of carbon atoms of the alkyl group is not particularly limited, but in order to maintain the solubility of the polymer, the number of carbon atoms is preferably 1 or more and 6 or less, more preferably 3 or less, and further preferably a methyl group or an ethyl group. ..

When ^{there are a plurality of R 1} and R ² in the repeating unit, R ¹ and R ² may be the same or different. ^{It is preferable that all R 1} and R ² are the same group because the charge can be uniformly distributed around the nitrogen atom and the synthesis is easy.

(R ³ and R ⁴ )
^{R 3} and R ⁴ in the repeating unit represented by the above formulas (2) -1 to (2) -3 each independently have an alkyl group and a substituent which may have a substituent. It is an alkoxy group which may be present, or an aralkyl group which may have a substituent. It is preferable that R ³ and R ⁴ are linear, branched or cyclic alkyl groups each independently which may have a substituent. The carbon number of the alkyl group is not particularly limited, but in order to maintain the solubility of the polymer, the carbon number is preferably 1 or more, more preferably 4 or more, preferably 12 or less, and further preferably 8. The following is particularly preferable, and it is a hexyl group.

(R ⁵ to R ⁷ and R ¹¹ to R ¹⁴ )
R ⁵ to R ⁷ and R ¹¹ to R ¹⁴ may independently have an alkyl group which may have a substituent, an alkoxy group which may have a substituent, and a substituent. It is an aromatic hydrocarbon group which may have an aralkyl group or a substituent. R ⁵ to R ⁷ and R ¹¹ to R ¹⁴ may independently have an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or an aralkyl group which may have a substituent. It is preferably a good aromatic hydrocarbon group.

The alkyl group is not particularly limited, but a long one is preferable in order to easily improve the solubility of the polymer, and a short one is preferable in order to improve the stability of the film and the charge transportability. The alkyl group preferably has 1 or more and 24 or less carbon atoms, more preferably 12 or less, further preferably 8 or less, particularly preferably 6 or less, more preferably 2 or more, still more preferably 3 or more, and particularly preferably 4 or more. preferable. Further, the alkyl group may have a linear, branched or cyclic structure.
Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, tert-butyl group and n-hexyl. Examples include a group, an n-octyl group, a cyclohexyl group, a dodecyl group and the like.

The alkoxy group is not particularly limited, but since it is easy to improve the solubility of the polymer, the number of carbon atoms is preferably 1 or more and 24 or less, more preferably 12 or less, further preferably 8 or less, particularly preferably 6 or less, and 2 or more. Is more preferable, 3 or more is further preferable, and 4 or more is particularly preferable.
Specific examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, an i-butoxy group, a tert-butoxy group, a hexyloxy group and the like.

The aralkyl group is not particularly limited, but since it is easy to improve the solubility of the polymer, the number of carbon atoms is preferably 7 or more and 60 or less, more preferably 40 or less, more preferably 8 or more, further preferably 10 or more, and 12 or more. Is particularly preferable.
Specific examples of the aralkyl group include 1,1-dimethyl-1-phenylmethyl group, 1,1-di (n-butyl) -1-phenylmethyl group, and 1,1-di (n-hexyl). -1-phenylmethyl group, 1,1-di (n-octyl) -1-phenylmethyl group, phenylmethyl group, phenylethyl group, 3-phenyl-1-propyl group, 4-phenyl-1-n-butyl Group, 1-methyl-1-phenylethyl group, 5-phenyl-1-n-propyl group, 6-phenyl-1-n-hexyl group, 6-naphthyl-1-n-hexyl group, 7-phenyl-1 Examples thereof include -n-heptyl group, 8-phenyl-1-n-octyl group and 4-phenylcyclohexyl group.

The aromatic hydrocarbon group is not particularly limited, but the number of carbon atoms is preferably 6 or more and 60 or less, more preferably 30 or less, further preferably 24 or less, and 14 or less because it is easy to improve the solubility of the polymer. Especially preferable.
Specific examples of the aromatic hydrocarbon group include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzpyrene ring, a chrysen ring, a triphenylene ring, an acenaphthene ring, and a fluorene ring. Examples thereof include monovalent groups of 6-membered monocyclic rings or 2 to 5 fused rings, such as fluorene rings, or groups in which 2 to 8 ring structures selected from these are linked. It is preferably a single ring or a group in which 2 to 4 or less are linked.

From the viewpoint of improving charge transportability and durability, R ⁵ to R ⁷ are preferably an alkyl group or an aromatic hydrocarbon group, R ⁵ and R ⁶ are more preferably an alkyl group, and R ⁷ is an aromatic hydrocarbon. It is more preferably a group, and the preferred number of carbon atoms is as described above.
^{R 5} and R ⁶ are preferably an alkyl group having 3 or more and 8 or less carbon atoms or an aralkyl group having 9 or more and 40 or less carbon atoms in terms of improving solubility and excellent charge transportability.

Alkyl group of the ^R 1 ~ ^{R 4,} alkoxy group, aralkyl ^group, the alkyl group of R 5 ~ ^{R 7} and ^R 11 ^{~ R 14,} alkoxy groups, aralkyl groups and aromatic hydrocarbon groups may further have a substituent May be. Further, the substituent which may be possessed is ^{a group listed as a preferable group of the alkyl group of R 5} to R ⁷ and R ¹¹ to R ¹⁴ , an alkoxy group, an aralkyl group and an aromatic hydrocarbon group, or a cross-linking group described later. Sex groups can be mentioned.
Alkyl group of the ^R 1 ~ ^{R 4,} alkoxy group, aralkyl ^group, the alkyl group of R 5 ~ ^{R 7} and ^R 11 ^{~ R 14,} alkoxy groups, aralkyl groups and aromatic hydrocarbon groups, from the viewpoint of low voltage Is most preferably free of substituents.

Substituents that R ⁵ to R ⁷ and R ¹¹ to R ¹⁴ may further have are insoluble in a solvent when the polymer of the present embodiment is formed into a film and then another layer is applied to form a film and laminated. From the viewpoint of improvement, it is preferable to use a crosslinkable group described later. ^{Among them, it is preferable that any one of R 5} , R ⁶ , and R ¹¹ to R ¹⁴ has a cross-linking group described later as a further substituent because it does not hinder the charge transport property, and at least of ^{R 5} and R ^6. It is more preferable that one has a crosslinkable group described later as a further substituent.

(A, b, c1 to c5, d1 to d4)
In the repeating unit represented by the formulas (2) -1 to (2) -2, a and b are independently integers of 0 to 4. It is preferable that a and b are 2 or less, respectively, and it is more preferable that both a and b are 0 or 1 at the same time.

In the repeating unit represented by the formulas (2) -1 to (2) -3, c1 to c5 are independently integers of 0 to 3. However, at least one of c3 and c5 is 1 or more, and d1 to d4 are independently integers of 1 to 4.
It is preferable that c1 to c5 and d1 to d4 are independently 2 or less.
It is more preferable that both c1 and c2 are 0 or 1 at the same time. It is more preferable that c1 and c2 are 1 or more.
It is preferable that at least one of c3 or c4, or both c3 and c4 are 1 or more. It is more preferable that both c3 and c4 are 1.
c5 is preferably 1 or more.
It is more preferable that c1 and c2, c3 and c4, and d1 to d4 are equal to each other. It is more preferable that all of c1 to c5 and d1 to d4 are 1 or 2. It is particularly preferable that all of c1 to c5 and d1 to d4 are 1.

Both c1 and c2 in the repeating unit represented by the formula (2) -1 is 1 or 2 simultaneously, and, when both a and b is 2 or 1, ^{R 1} and ^{R 2} are, Most preferably, they are connected to each other at symmetrical positions.
Formula (2) both c3 and c4 in the repeating unit represented by -2 1 or 2 simultaneously, and, when both a and b is 2 or 1, ^{R 1} and ^{R 2} are, Most preferably, they are connected to each other at symmetrical positions.

Here, ^{regarding the fact that R 1} and R ² are coupled to each other at symmetrical positions, an example in the case where Q = C, c1 = c2 = 1, and a = b = 2 in the above equation (2) -1. As an example, the following equations (1-1) and (1-2) will be described.
The fact that R ¹ and R ² are bonded to each other at symmetrical positions means that the bonding positions of ^{R 1} and R ² are relative to the fluorene ring of the main chain in the following equations (1-1) and (1-2). Is the target. At this time, 180 degree rotation about the main chain is regarded as the same structure. For example, in the following formulas (1-1), 'and ^{R 2'} ^{R 1} and the target, ^{R 1} "and ^{R 2"} and it is the target, the equation (1-1) and (1-2) Consider the same structure.

(Concrete example)
Specific examples of the preferred repeating unit structure include the following structures.

[Terminal group]
In the present embodiment, the terminal group refers to the structure of the terminal portion of the polymer formed by the end cap agent used at the end of the polymerization of the polymer. The terminal group of the polymer of this embodiment is usually a hydrocarbon group. From the viewpoint of charge transportability, the hydrocarbon group preferably has 1 or more and 60 or less carbon atoms, more preferably 1 or more and 40 or less, and further preferably 1 or more and 30 or less.

The terminal group preferably includes the following.
For example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, tert-butyl group, n-hexyl group, cyclohexyl group, dodecyl group and the like. , Usually 1 or more, preferably 4 or more, usually 24 or less, preferably 12 or less, linear, branched, or cyclic alkyl groups;
For example, an alkenyl group such as a vinyl group having a carbon number of usually 2 or more, usually 24 or less, preferably 12 or less;
For example, an alkynyl group having a carbon number of usually 2 or more, usually 24 or less, preferably 12 or less, such as an ethynyl group;
For example, an aromatic hydrocarbon ring group having a carbon number of usually 6 or more, usually 36 or less, preferably 24 or less, such as a phenyl group or a naphthyl group:

These hydrocarbon groups may further have a substituent. Further, the substituent which may be possessed is preferably an alkyl group or an aromatic hydrocarbon group. When there are a plurality of these substituents which may be further present, they may be bonded to each other to form a ring.
The substituent that the hydrocarbon group of the terminal group may further have is preferably an alkyl group or an aromatic hydrocarbon group from the viewpoint of charge transportability and durability, and more preferably an aromatic hydrocarbon. It is a group.

[Soluble group]
The polymer of the present embodiment preferably has a soluble group for soluble expression in a solvent. The soluble group in the present embodiment is a group having a linear or branched alkyl group or alkylene group having 3 or more and 24 or less carbon atoms, preferably 12 or less carbon atoms. Among these, an alkyl group, an alkoxy group, or an aralkyl group is preferable, and for example, an n-propyl group, a 2-propyl group, an n-butyl group, an isobutyl group, an n-hexyl group, an n-octyl group and the like. .. More preferably, it is an n-hexyl group or an n-octyl group. The soluble group may have a substituent.

(Number of soluble groups)
It is preferable that the number of soluble groups contained in the polymer of the present embodiment is large in that it is easy to obtain a polymer solution that can be used in the wet film forming method. On the other hand, when another layer is formed on the layer formed by using the polymer of the present embodiment by the wet film forming method, the film thickness is less reduced due to the lower layer being dissolved in the solvent. Less is preferable.

The number of soluble groups contained in the polymer of the present embodiment can be expressed by the number of moles per gram of the polymer.
When the number of soluble groups contained in the polymer of the present embodiment is expressed in terms of the number of moles per 1 g of the polymer, it is usually 4.0 mmol or less, preferably 3.0 mmol or less, more preferably 3.0 mmol or less per 1 g of the polymer. It is 2.0 mmol or less, and usually 0.1 mmol or more, preferably 0.5 mmol or more.
When the number of soluble groups is within the above range, the polymer is easily dissolved in a solvent, and a composition containing a polymer suitable for a wet film forming method can be easily obtained. Further, since the soluble group density is appropriate and the solubility in an organic solvent after drying with a heating solvent is sufficient, a multilayer laminated structure can be formed by a wet film forming method.

The number of soluble groups per gram of the polymer can be calculated from the molar ratio of the charged monomer at the time of synthesis and the structural formula by removing the terminal group from the polymer.
Explaining the case of the polymer 1 represented by the formula (HT-1) used in Example 1 described later, as shown below, in the polymer 1, the molecular weight of the repeating unit excluding the terminal group is 748 on average. The average number of hexyl groups, which is 4 and is a soluble group, is 1.3 per repeating unit. When this is calculated by simple proportionality, the number of soluble groups per 1 g of molecular weight is calculated to be 1.74 mmol.

[Crosslinkable group]
The polymer of this embodiment may have a crosslinkable group. The crosslinkable group in the polymer of the present embodiment may be present in the repeating unit represented by the formula (1), and is in a repeating unit different from the repeating unit represented by the formula (1). May be present in. In particular, it is preferable to have a crosslinkable group in the aromatic hydrocarbon group or the aromatic heterocyclic group bonded as a side chain because the crosslinking reaction can easily proceed.
By having a crosslinkable group, it is possible to make a large difference in solubility in an organic solvent before and after a reaction (poor solubility reaction) caused by irradiation with heat and / or active energy rays.

A crosslinkable group is a group that forms a new chemical bond by reacting with a group constituting another molecule located in the vicinity of the crosslinkable group by irradiation with heat and / or active energy rays. To say. In this case, the reacting group may be the same group as the crosslinkable group or a different group.

As the crosslinkable group, a cyclobutene ring fused to the aromatic ring and a group containing an alkenyl group bonded to the aromatic ring are preferable, and a group selected from the following crosslinkable group group K is more preferable. It is preferable that the crosslinkable group is contained in the polymer in a form further substituted with the substituent having each structure.

(Crosslinkable group K)
The crosslinkable group K has the structure shown below.

In the crosslinkable group group K, R ²¹ to R ²³ each independently represent a hydrogen atom or an alkyl group. R ²⁴ to R ²⁶ each independently represent an alkyl group or an alkoxy group. p represents an integer of 1 to 4, q represents an integer of 1 to 4, and r represents an integer of 1 to 4.
When p is 2 or more, the plurality of R ^24s may be the same or different, and adjacent R ^24s may be bonded to each other to form a ring.
When q is 2 or more, a plurality of R ^25s may be the same or different, and adjacent R ^25s may be bonded to each other to form a ring.
When r is 2 or more, the plurality of R ^26s may be the same or different, and adjacent R ^26s may be bonded to each other to form a ring.
Ar ²¹ and Ar ²² each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group which may have a substituent.
"-*" Is a binding site.

Examples ^{of the alkyl group of R 21} to R ²⁶ include a linear or branched chain alkyl group having 6 or less carbon atoms. For example, a methyl group, an ethyl group, an n-propyl group, a 2-propyl group, an n-butyl group, an isobutyl group and the like. More preferably, it is a methyl group or an ethyl group. Since ^{the alkyl groups of R 21} to R ²⁶ have 6 or less carbon atoms, it is considered that the film formed by the polymer of the present embodiment is likely to be insolubilized without sterically inhibiting the cross-linking reaction. ..

Examples ^{of the alkoxy group of R 24} to R ²⁶ include a linear or branched chain alkoxy group having 6 or less carbon atoms. For example, a methoxy group, an ethoxy group, an n-propoxy group, a 2-propoxy group, an n-butoxy group and the like. More preferably, it is a methoxy group or an ethoxy group. When the ^{number of carbon atoms of R 24} to R ²⁶ is 6 or less, it is considered that the film formed by the polymer of the present embodiment is likely to be insolubilized without sterically inhibiting the cross-linking reaction.

Examples of the aromatic hydrocarbon group which may have a substituent of Ar ²¹ and Ar ²² include a single ring of a 6-membered ring such as a benzene ring and a naphthalene ring having one free valence, or 2 to 2 to. Examples include a 5-fused ring. In particular, a benzene ring having one free valence is preferable.
Ar ²² may be a group in which two or more aromatic hydrocarbon groups which may have a substituent are bonded. Examples of such a group include a biphenylene group and a terphenylene group, and a 4,4'-biphenylene group is preferable.
Examples of the aromatic heterocyclic group which may have a substituent of Ar ²¹ and Ar ²² include a single ring of a 6-membered ring having one free valence, such as a pyridine ring and a triazine ring, or 2 to 2 to Examples include a 5-fused ring. In particular, a triazine ring having one free valence is preferable.
The ^{substituents that Ar 21} and Ar ²² may have are the same as those of the above-mentioned substituent group Z.

Ionization of arylvinylcarbonyl groups such as cinnamoyl groups, benzocyclobutene rings having a monovalent free valence, and 1,2-dihydrocyclobuta [a] naphthalene rings having a monovalent free valence as crosslinkable groups. A group that undergoes an addition reaction is preferable in that it further improves the electrochemical stability of the device.

Among the crosslinkable groups, the cyclobutene ring fused to an aromatic ring having a monovalent free valence and the 1,2-dihydrocyclobutane having a monovalent free valence are particularly stable in the structure after cross-linking. [A] A group containing a naphthalene ring is preferable, and among them, a benzocyclobutene ring or a 1,2-dihydrocyclobuta [a] naphthalene ring having a monovalent free valence is more preferable. As the crosslinkable group, a 1,2-dihydrocyclobuta [a] naphthalene ring having a monovalent free valence in that the crosslinking reaction temperature is low is particularly preferable.

(Number of crosslinkable groups)
It is preferable that the crosslinkable group contained in the polymer of the present embodiment is sufficiently insolubilized by crosslinking, and it becomes easy to form another layer on the crosslinkable group by a wet film forming method. On the other hand, it is preferable that the number of crosslinkable groups is small in that cracks are unlikely to occur in the formed layer, unreacted crosslinkable groups are unlikely to remain, and the organic electroluminescent device tends to have a long life.

In the polymer of the present embodiment, the number of crosslinkable groups present in one polymer chain is preferably 1 or more, more preferably 2 or more, and preferably 200 or less, more preferably 100 or less. ..

The number of crosslinkable groups contained in the polymer of the present embodiment can be represented by the number per 1000 molecular weight of the polymer.
When the number of crosslinkable groups contained in the polymer of the present embodiment is expressed by the number per 1000 molecular weight of the polymer, it is usually 3.0 or less, preferably 2.0 or less, more preferably 2.0 or less per 1000 molecular weight. The number is 1.0 or less, and usually 0.01 or more, preferably 0.05 or more.

When the number of crosslinkable groups is within the above range, cracks and the like are unlikely to occur, and a flat film can be easily obtained from the polymer of the present embodiment. Further, since the cross-linking density is appropriate, there are few unreacted cross-linking groups remaining in the layer after the cross-linking reaction, and it is unlikely to affect the life of the obtained device.
Further, since the poor solubility in the organic solvent after the crosslinking reaction is sufficient, it is easy to form a multilayer laminated structure by the wet film forming method.

The number of crosslinkable groups per 1000 molecular weight of the polymer can be calculated from the molar ratio of the charged monomer at the time of synthesis and the structural formula by removing the terminal group from the polymer.
Explaining the case of the polymer 1 represented by the formula (HT-1) used in Example 1 described later, in the polymer 1, the molecular weight of the repeating unit excluding the terminal group is 748.4 on average, and cross-linking is performed. The number of sex groups is 0.15 per repeating unit. When this is calculated by simple proportionality, the number of crosslinkable groups per 1000 molecular weight is calculated to be 0.20.

[Content of repeating unit]
In the polymer of the present embodiment, the content of the repeating unit represented by the formula (1) is not particularly limited, but it is usually contained in the polymer in an amount of 5 mol% or more, preferably 10 mol% or more, and 15 It is more preferably contained in an amount of mol% or more, and particularly preferably contained in an amount of 20 mol% or more. In the polymer of the present embodiment, the repeating unit may be composed of only the repeating unit represented by the formula (1), but for the purpose of balancing various performances when the organic electroluminescent device is used, the formula (1) It may have a repeating unit different from that of 1). In that case, the content of the repeating unit represented by the formula (1) in the polymer is usually 99 mol% or less, preferably 95 mol% or less.

[Preferable repeating unit that may be contained elsewhere]
It is also preferable that the polymer of the present embodiment further contains a repeating unit represented by the following formula (3). The repeating unit represented by the formula (3) is preferably a repeating unit represented by any of the following (3) -1, formula (3) -2 or formula (3) -3.

(In equations (3) -1 to (3) -3,
Ar ⁷ represents an aromatic hydrocarbon group which does not contain a partial structure A and may have a substituent or an aromatic heterocyclic group which may have a substituent.
Q represents -C (R ⁵ ) (R ⁶ )-, -N (R ⁷ )-or -C (R ¹¹ ) (R ¹² ) -C (R ¹³ ) (R ¹⁴ )-.
R ¹ to R ⁴ each independently represent an alkyl group which may have a substituent, an alkoxy group which may have a substituent, or an aralkyl group which may have a substituent.
R ⁵ to R ⁷ and R ¹¹ to R ¹⁴ may independently have an alkyl group which may have a substituent, an alkoxy group which may have a substituent, and a substituent. Represents an aromatic hydrocarbon group which may have an aralkyl group or a substituent.
a and b are independently integers of 0 to 4.
c1 to c5 are independently integers of 0 to 3.
However, at least one of c3 and c5 is 1 or more.
d1 to d4 are independently integers of 1 to 4.
When ^{there are a plurality of R 1} , R ² , R ³ , and R ⁴ in the repeating unit, R ¹ , R ² , R ³ , and R ⁴ may be the same or different.
However, ^Q, R 1 ~ ^{R 4,} the formula (2) -1 ^Q in ~ the formula (2) ^-3, and it may take the same structure as R 1 - ^{R 4,} preferred ranges are also the same. Therefore, the same reference numerals are used, but they may be different.
c1 to c5 and d1 to d4 can take the same values as c1 to c5 and d1 to d4 in the formulas (2) -1 to (2) -3, and the preferable range is also the same. Therefore, the same reference numerals are used, but they may be different. )

(Ar ⁷ )
In the repeating units represented by the formulas (3) -1 to (3) -3, Ar ⁷ may independently have a substituent containing no partial structure A in each repeating unit. Represents an aromatic heterocyclic group which may have an aromatic hydrocarbon group or a substituent.

The aromatic hydrocarbon group preferably has 6 or more carbon atoms and 60 or less carbon atoms. Specifically, 6-membered rings such as benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzpyrene ring, chrysene ring, triphenylene ring, acenaphthene ring, fluoranthene ring, and fluorene ring. Examples thereof include a monocyclic ring, a 2 to 5 fused ring, or a monovalent group in which a plurality of rings selected from these are linked. When a plurality of them are linked, a monovalent group in which 2 to 10 are linked is preferable.

The aromatic heterocyclic group preferably has 3 or more carbon atoms and 60 or less carbon atoms. Specifically, a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carbazole ring, a pyroloymidazole ring, a pyrrolopyrazole ring, a pyrrolopyrrole ring, Thienopyrrole ring, thienothiophene ring, flopyrrole ring, furan ring, thienofran ring, benzoisoxazole ring, benzoisothiazole ring, benzimidazole ring, pyrazine ring, pyridazine ring, quinoline ring, isoquinoline ring, cinnoline ring, quinoxalin ring, phenant Examples thereof include a 5- to 6-membered monocyclic ring, a 2- to 4-condensed ring, or a monovalent group in which a plurality of rings selected from these are linked, such as a lysine ring, a perimidine ring, a quinazoline ring, and a quinazolinone ring. When a plurality of them are linked, a monovalent group in which 2 to 10 are linked is preferable.

Ar ⁷ is preferably an aromatic hydrocarbon group which may have a substituent from the viewpoint of excellent charge transportability and durability. Among them, a monovalent group of a benzene ring or a fluorene ring which may have a substituent, that is, a phenyl group or a fluorenyl group which may have a substituent is more preferable, and a substituent may be provided. A fluorenyl group is more preferred, and a 2-fluorenyl group, which may have a substituent, is particularly preferred.

The ^{substituent that the aromatic hydrocarbon group of Ar 7} may have is not particularly limited as long as it does not significantly reduce the characteristics of the polymer of the present embodiment. Preferably, a group selected from the substituent group Z or the crosslinkable group is mentioned. As the substituent, an alkyl group, an alkoxy group, an aromatic hydrocarbon group, an aromatic heterocyclic group not corresponding to the partial structure A or the crosslinkable group is preferable, and an alkyl group is more preferable.

From ^{the viewpoint of solubility in a coating solvent, Ar 7} is preferably a fluorenyl group substituted with an alkyl group having 1 to 24 carbon atoms, and particularly a 2-fluorenyl group substituted with an alkyl group having 4 to 12 carbon atoms. preferable. Further, a 9-alkyl-2-fluorenyl group in which the alkyl group is substituted at the 9-position of the 2-fluorenyl group is preferable, and a 9,9'-dialkyl-2-fluorenyl group in which the alkyl group is 2-substituted is particularly preferable. Since at least one of the 9-position and the 9'-position is a fluorenyl group substituted with an alkyl group, the solubility in a solvent and the durability of the fluorene ring are likely to be improved. Further, since both the 9-position and the 9'-position are substituted with an alkyl group, the solubility in a solvent and the durability of the fluorene ring are likely to be further improved.
It ^{is preferable that Ar 7} contains the crosslinkable group because the insolubility in the solvent is improved when the film is laminated and coated after the film formation.

From the viewpoint of insolubilization, it is preferable that the further substituent contains a repeating unit represented by the formulas (3) -1 to (3) -3 containing at least one of the above-mentioned crosslinkable groups. The crosslinkable group is preferably further substituted with a substituent which the aromatic hydrocarbon group represented by ^{Ar 7 may have.}

(Concrete example)
Specific examples of the repeating unit structure represented by the formulas (3) -1 to (3) -3 include the following structures.

[Other repeating units]
The polymer of the present embodiment may further contain a repeating unit represented by the following formula (4) or the following formula (5) in terms of charge transportability and durability.

In formula (4), R ⁸ and R ⁹ are each independently a hydrogen atom, an alkyl group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, or a substituent. Represents an aromatic heterocyclic group which may have a group.

In formula (5), Ar ¹⁰ has a divalent aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a substituent. Two or more groups selected from a divalent aromatic hydrocarbon group which may be present and a divalent aromatic heterocyclic group which may have a substituent are linked directly or via a linking group. Represents a valence group.

(R ⁸ and R ⁹ )
Examples of the alkyl group, aromatic hydrocarbon group and aromatic heterocyclic group of R ⁸ and R ⁹ include the alkyl group exemplified as the substituent group Z, the aromatic hydrocarbon group and the aromatic heterocyclic group. The substituents that these groups may have are preferably a group similar to the substituent group Z or the crosslinkable group.

(Ar ¹⁰ )
As ^{a specific structure of Ar 10,} a divalent group similar to ^{Ar 2 in the} above formula (1) can be mentioned. The substituents that these groups may have are preferably a group similar to the substituent group Z or the crosslinkable group.

[Molecular weight of polymer]
The weight average molecular weight (Mw) of the polymer of the present embodiment is usually 3,000,000 or less, preferably 1,000,000 or less, more preferably 500,000 or less, still more preferably 200,000 or less, particularly preferably. Is 100,000 or less, usually 10,000 or more, preferably 15,000 or more.

When the weight average molecular weight of the polymer is not more than the above upper limit value, solubility in a solvent is obtained, and the film forming property tends to be excellent. When the weight average molecular weight of the polymer is at least the above lower limit value, the decrease in the glass transition temperature, the melting point and the vaporization temperature of the polymer may be suppressed, and the heat resistance may be improved. In addition, the coating film after the cross-linking reaction may be sufficiently insoluble in the organic solvent.

The number average molecular weight (Mn) of the polymer of the present embodiment is usually 2.5 million or less, preferably 750,000 or less, more preferably 400,000 or less, particularly preferably 100,000 or less, and usually 2 It is 3,000 or more, preferably 4,000 or more, more preferably 8,000 or more, and even more preferably 20,000 or more.

The dispersity (Mw / Mn) in the polymer of the present embodiment is preferably 3.5 or less, more preferably 2.5 or less, and particularly preferably 2.0 or less. The smaller the value of the dispersion, the better, so the lower limit is ideally 1. When the dispersity of the polymer is not more than the above upper limit value, purification is easy, and solubility in a solvent and charge transporting ability are good.

Usually, the weight average molecular weight and the number average molecular weight of the polymer are determined by SEC (size exclusion chromatography) measurement. In the SEC measurement, the higher the molecular weight component, the shorter the elution time, and the lower the molecular weight component, the longer the elution time. By conversion, the weight average molecular weight and the number average molecular weight are calculated.

[Preferable polymer]
The polymer of the present embodiment is most preferably represented by any of the following formulas (6a) to (6h).

In each of the polymers of the formulas (6a) to (6h), A, Q, R ¹ , R ² , R ³ , and R ⁴ are the same as those in the formulas (2) -1 to (2) -3. Ar ⁷ is the same as in the above equations (3) -1 to (3) -3. At least one A or Ar ^{7 in} each polymer preferably has the above-mentioned crosslinkable group. n and m represent the number of repetitions.

[Concrete example]
Below, the weight of the present embodiment other than the polymer 1 represented by the formula (HT-1) and the polymers represented by the formulas (HT-2) and (HT-4) used in the examples described later. A specific example of coalescence is shown. The polymer of the present embodiment is not limited to these. The numbers in the following chemical formulas represent the molar ratio of repeating units.
These polymers may be any of a random copolymer, an alternating copolymer, a block copolymer, a graft copolymer and the like, and the arrangement order of the repeating units is not limited.

[Method for producing polymer]
The method for producing the polymer of the present embodiment is not particularly limited. For example, it can be produced by a polymerization method by Suzuki reaction, a polymerization method by Grignard reaction, a polymerization method by Yamamoto reaction, a polymerization method by Ullmann reaction, a polymerization method by Buchwald-Hartwig reaction, or the like.

In the case of the polymerization method by the Ullmann reaction and the polymerization method by the Buchwald-Hartwig reaction, for example, the aryl dihalide represented by the following formula (1a) (E represents a halogen atom such as I, Br, Cl, F) and the formula. The polymer of the present embodiment is synthesized by reacting with the primary aminoaryl represented by (1b) and further reacting with the dial halide represented by the formula (2a).

In the above ^{^{formula, A, R 1 ~ R 2}} , Q, a, b, c1, d1 has the same meaning as the formula (2) -1 to (2) -3. n and m represent the number of repetitions.

In the above polymerization method, the reaction for forming an N-aryl bond is usually carried out in the presence of a base such as potassium carbonate, tert-butoxysodium or triethylamine. It can also be carried out in the presence of a transition metal catalyst such as a copper or palladium complex.

[Small molecule compound]
The partial structure A-containing material contained in the light emitting layer, which is one embodiment of the present invention, is preferably a small molecule compound. The partial structure A-containing material of the small molecule compound is a compound having a molecular weight of 5,000 or less represented by the following formula (10), the following formula (11), or the following formula (12) (hereinafter, these compounds are referred to as “these compounds”. It may be referred to as a "small molecule compound of the present embodiment").

(B)
B in the above formula (10) and the above formula (11) is not particularly limited, but preferably a functional group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, and the like. It is selected from an aromatic heterocyclic group which may have a substituent, or an aromatic hydrocarbon group which may have a substituent and an aromatic heterocyclic group which may have a substituent 2 Examples thereof include a group in which a plurality of the above groups are directly linked or linked via a linking group.

Functional groups include a structure having hole transportability, a structure having electron transportability, a structure that suppresses charge transport, a structure that imparts solubility in an organic solvent, a structure that inhibits crystallization and improves amorphousness, and a structure. Alternatively, a group containing a structure having luminescence is preferable.
As the structure having hole transportability, an aromatic amine structure, that is, a group containing at least one aromatic hydrocarbon group bonded to a nitrogen atom of the amine is preferable.

Two or more groups selected directly from an aromatic hydrocarbon group, an aromatic heterocyclic group, an aromatic hydrocarbon group which may have a substituent and an aromatic heterocyclic group which may have a substituent are directly Alternatively, as a plurality of groups linked via a linking group, those based on the same structure as ^{Ar 0 in the above formula (31) are preferable.}

As the position of A to which B is bonded, it is preferable that at least one B is bonded to the ring HA in the partial structure A.

The small molecule compound of this embodiment is preferably a charge transport material in the light emitting layer. The small molecule compound of the present embodiment is preferably a compound represented by the above formula (10) or the above formula (12).

The compound represented by the formula (10) is preferably a compound represented by the following formula (10A) or the following formula (10B). The compound represented by the formula (12) is preferably a compound represented by the following formula (12A).

(In formula (10A),
HA represents any of the trivalent aromatic heterocyclic groups represented by the following structural formulas (10A-a), (10A-b) and (10A-c).
Xa ¹ , Ya ¹ , and Za ¹ each independently have a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms, which may have a substituent, or a carbon which may have a substituent. Represents a divalent aromatic heterocyclic group of numbers 3 to 30.
Each of Xa ² , Ya ² and Za ² independently has a hydrogen atom, an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or a carbon number which may have a substituent. Represents 3 to 30 aromatic heterocyclic groups.
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.
When g11, h11, and j11 are 2 or more, Xa ¹ , Ya ¹ , and Za ¹ may be the same or different.
R ³¹ represents a hydrogen atom or a substituent. The four R ^31s may be the same or different. )

(In formulas (10A-a) to (10A-c), * represents the bonding position.)

In the formulas (10A), (10B), and (12A), the aromatic hydrocarbon ring of the aromatic hydrocarbon group having 6 to 30 carbon atoms is preferably a 6-membered single ring or a 2 to 5 condensed ring. .. Specific examples thereof include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a fluorene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzpyrene ring, a chrysene ring, a triphenylene ring, and a fluoranthene ring. More preferably, it is a monocyclic ring or a 2-3 condensed ring, and specific examples thereof include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, and a fluorene ring. Of these, a benzene ring, a naphthalene ring, a phenanthrene ring, and a fluorene ring are preferable, and a benzene ring or a fluorene ring is more preferable.

In the formulas (10A), (10B), and (12A), the aromatic heterocycle of the aromatic heterocyclic group having 3 to 30 carbon atoms is a 5- or 6-membered single ring, or a 2 to 5 condensation thereof. Rings are preferred. Specifically, furan ring, benzofuran ring, dibenzofuran ring, thiophene ring, benzothiophene ring, dibenzothiophene ring, pyrol ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, indolocarbazole ring, Pyrroylmidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, flopyrol ring, flofuran ring, thienofuran ring, benzoisoxazole ring, benzoisothiazole ring, benzoimidazole ring, pyridine ring, pyrazine ring, pyridazine ring , Pyrimide ring, triazine ring, quinoline ring, isoquinoline ring, shinoline ring, quinoxaline ring, perimidine ring, quinazoline ring, quinazolinone ring and the like.
Of these, the thiophene ring, pyrrole ring, imidazole ring, pyridine ring, pyrimidine ring, triazine ring, quinoline ring, quinazoline ring, carbazole ring, dibenzofuran ring, dibenzothiophene ring, indolocarbazole ring, phenanthroline ring, or indolocarbazole ring are preferable. It is more preferably a pyridine ring, a pyrimidine ring, a triazine ring, a quinoline ring, a quinazoline ring, a carbazole ring, a dibenzofuran ring, a dibenzothiophene ring, or an indolocarbazole ring, and more preferably a carbazole ring, a dibenzofuran ring, or a dibenzo ring. It is a thiophene ring or an indolocarbazole ring.

^{Xa 2} , Ya ² , Za ² in the formula (10A) ^{, Yb 2} in the case of q13 = 0 in the formula (10B) ^{, Zb 2} in the case of r13 = 0, ^{Xc 2} , Yc in the formula (12A). ^{In 2} , a particularly preferable aromatic hydrocarbon ring is a benzene ring, a naphthalene ring or a phenanthrene ring, and a particularly preferable aromatic heterocycle is a carbazole ring, a dibenzofuran ring, a dibenzothiophene ring, or an indolocarbazole ring, which is aromatic. Group hydrocarbon rings are more preferred.

When it is a substituent, R ³¹ is preferably an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent or an aromatic having 3 to 30 carbon atoms which may have a substituent. It is a group heterocyclic group. From the viewpoint of improving durability and charge transportability, it is more preferable that the aromatic hydrocarbon group may have a substituent. When there are a plurality of R ^{31s as} substituents, they may be different from each other.

The above-mentioned hydrocarbon aromatic ring having 6 to 30 carbon atoms may have a substituent, a heteroaromatic ring having 3 to 30 carbon atoms may have a substituent, and the substituent R ³¹ has. The substituents may be the same as the substituents listed in the substituent group Z or the crosslinkable group in the polymer of the present embodiment, and the preferred substituents are also the same. The same applies to the substituents that the substituents may further have.

The compound represented by the formula (10A) is more preferably a compound represented by the following general formulas (10A-1) to (10A-3).

(In formulas (10A-1) to (10A-3),
Xa ¹ , Ya ¹ , Za ¹ , Xa ² , Ya ² , and Za ² are synonymous with those in equation (10).
R ³³ represents a hydrogen atom or a substituent. The plurality of R ^33s may be the same or different.
g11', h11' and j11'independently represent integers from 0 to 5.
When g11', h11', and j11' are 2 or more, the plurality of Xa ¹ , Ya ¹ , and Za ¹ may be the same or different. )

In each of the above formulas (10A-1) to (10A-3), a partial structure in which one of the three benzene rings is bonded to the central pyridine ring, pyrimidine ring, or triazine ring is partially formed. ^{R 33} , which can be regarded as the structure A and is bonded to the benzene ring constituting the partial structure A, corresponds to ^{R 31} in the formula (10A).

The compound represented by the formula (10B) is preferably a compound represented by the following formula (10B-1).

A group when ^{R 33} is a substituent in the formulas (10A-1) to (10A-3) and (10B-1), and a substitution which may be further possessed when ^{R 33 is a substituent.} group is the same as the ^{R 31.}

[Molecular weight]
The molecular weight of the small molecule compound of the present embodiment is usually 5,000 or less, preferably 4,000 or less, particularly preferably 3,000 or less, most preferably 2,000 or less, usually 300 or more, preferably 350 or more. , More preferably 400 or more. Since the molecular weight of the small molecule compound of the present embodiment contains the required partial structure A, the molecular weight is usually equal to or higher than the above lower limit.

[Concrete example]
Specific examples of the small molecule compound of this embodiment are shown below. The small molecule compounds of this embodiment are not limited to these.

[Light emitting dopant]
It is also preferable that the partial structure A-containing material, which is a small molecule compound contained in the light emitting layer according to one embodiment of the present invention, is a light emitting dopant. The light emitting dopant is preferably a compound represented by the following formula (40). In the following formula (40), the ring HA in the partial structure A represented by the formula (31) ^{corresponds to the triazine ring, and Ar 0} corresponds to the pyridine ring. ^{R 44 in the} formula (40) may have an aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or an aromatic which may have a substituent. When two or more groups selected from group aromatic heterocyclic groups which may have a group hydrocarbon group and a substituent are linked to be a monovalent group, n1 is 2 and the other Ar. ⁰ is R ⁴⁴ .

In the above formula (40), R ⁴¹ , R ⁴² , and R ⁴³ independently have an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, and an alkoxy having 1 to 20 carbon atoms. Group, (hetero) aryloxy group with 3 to 20 carbon atoms, alkylsilyl group with 1 to 20 carbon atoms, arylsilyl group with 6 to 20 carbon atoms, alkylcarbonyl group with 2 to 20 carbon atoms, 7 to 20 carbon atoms Arylcarbonyl group, alkylamino group having 1 to 20 carbon atoms, arylamino group having 6 to 20 carbon atoms, or (hetero) aryl group having 3 to 30 carbon atoms. These groups may further have substituents. When a ^{plurality of R 41} , R ⁴² , and R ⁴³ exist, they may be the same or different from each other. If R ¹ there are a plurality bonded R ¹ adjacent to each other may form a ring.
a40 is an integer of 0 to 4, b40 is an integer of 0 to 3, and c40 is an integer of 0 to 5.

R ⁴⁴ independently has a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an alkyl group having 1 to 20 carbon atoms, a (hetero) arylyl group having 7 to 40 carbon atoms, and an alkoxy group having 1 to 20 carbon atoms. , A (hetero) aryloxy group having 3 to 20 carbon atoms, an alkylsilyl group having 1 to 20 carbon atoms, an arylsilyl group having 6 to 20 carbon atoms, an alkylcarbonyl group having 2 to 20 carbon atoms, and 7 to 20 carbon atoms. It is an arylcarbonyl group, an alkylamino group having 2 to 20 carbon atoms, an arylamino group having 6 to 20 carbon atoms, or a (hetero) aryl group having 3 to 20 carbon atoms. These groups may further have substituents. When a ^{plurality of R 44s} exist, they may be the same or different from each other.
L ¹ represents an organic ligand, and m40 is an integer of 1 to 3.

R ⁴¹ to R ⁴⁴ are independent of each other, and from the viewpoint of durability, an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, an arylamino group having 6 to 20 carbon atoms, or a carbon. More preferably, it is a (hetero) aryl group having 3 to 30 carbon atoms or a (hetero) aryl group having 3 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, or the like. It is more preferably an (hetero) aryl group having 3 to 20 carbon atoms, and even more preferably an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 40 carbon atoms or an aryl group having 6 to 20 carbon atoms. preferable.
The ^{substituent that R 41} to R ⁴⁴ may further have is preferably a substituent selected from the substituent group Z.
When a40 is 2 or more, two adjacent R ^41s may be combined with each other to form a ring.

Examples of a plurality of R ^{41s in} which adjacent R ^41s are bonded to each other to form a ring include fluorene, naphthalene, dibenzothiophene, and dibenzofuran. From the viewpoint of stability, fluorene is particularly preferable.
From the viewpoint of lengthening the emission wavelength, ^{it is preferable that adjacent R 41s} are bonded to each other to form a ring.

Further, from the viewpoint of not lengthening the emission wavelength, ^{it is preferable that the adjacent R 41s} do not bond with each other to form a ring. That is, it is preferable that a40 in the formula (40) is 1, or a40 is 2 or more, and adjacent R ^41s do not have a ring bonded to each other.

The a40 is preferably 0 from the viewpoint of easy production, preferably 1 or 2 from the viewpoint of enhancing durability and solubility, and further preferably 1. b40 is preferably 0 from the viewpoint of easy production, and preferably 1 from the viewpoint of enhancing solubility.
Since there are many structures having a high electron acceptability including a triazine ring and LUMO is more stabilized, m40 is preferably 2 or 3, and more preferably 3.

L ¹ is an organic ligand and is not particularly limited, but is preferably a monovalent bidentate ligand, and is more preferably selected from the following chemical formulas. The broken line in the following chemical formula represents a coordination bond. When two organic ligands L ¹ is present, the organic ligand L ¹ may have a different structure from each other. In addition, when m40 is 3, ^{L 1} does not exist.
For m40 is less than 3 in the formula (40), ^{L 1} is represented by the following formula (3), Equation (4), and preferably has at least one structure selected from the group consisting of Formula (5).

In the above formulas (3), (4) and (5), R ⁴⁹ and R ⁵⁰ are synonymous with ^{R 41} in the above formula (40). That is, ^{it is selected from the same group as the substituent selected as R 41} , and the preferred example is also the same, and may further have a substituent. When a ^{plurality of R 49} and R ⁵⁰ exist, they may be the same or different from each other.

R ⁵¹ to R ⁵³ are independently substituted with an alkyl group having 1 to 20 carbon atoms which may be substituted with a hydrogen atom and a fluorine atom, a phenyl group which may be substituted with an alkyl group having 1 to 20 carbon atoms, or a phenyl group which may be substituted with an alkyl group having 1 to 20 carbon atoms. It is a halogen atom.

G is an integer from 0 to 4. h is an integer from 0 to 4.

Ring B ⁴⁰ is a pyridine ring, a pyrimidine ring, an imidazole ring, a quinoline ring, an isoquinoline ring, a quinazoline ring, a quinoxaline ring, an azatriphenylene ring, a carboline ring, a benzothiazole ring, or a benzoxazole ring. Ring B ⁴⁰ may further have a substituent.

The ^{substituents that R 49} , R ⁵⁰ , and ring B ⁴⁰ may further have are preferably substituents selected from the substituent group Z.
Further preferable R ⁴⁹ and R ⁵⁰ are independently alkyl groups having 1 to 20 carbon atoms or aryl groups having 6 to 30 carbon atoms which may be substituted with alkyl groups having 1 to 20 carbon atoms. Here, the aryl group having 6 to 30 carbon atoms is a group in which a plurality of monocyclic, bicyclic condensed rings, tricyclic condensed rings, monocyclic, dicyclic fused rings, or tricyclic condensed rings are linked.

G and h are preferably 0 from the viewpoint of easy production, preferably 1 or 2 from the viewpoint of enhancing solubility, and even more preferably 1.

R ⁵¹ to R ⁵³ are independently substituted with an alkyl group having 1 to 20 carbon atoms which may be substituted with a hydrogen atom and a fluorine atom, and a phenyl group or a halogen which may be substituted with an alkyl group having 1 to 20 carbon atoms, respectively. Representing an atom, preferably R ⁵¹ and R ⁵³ are methyl or t-butyl groups, and R ⁵² is a hydrogen atom, an alkyl or phenyl group having 1 to 20 carbon atoms.

From the viewpoint of durability, the ring B ⁴⁰ is preferably a pyridine ring, a pyrimidine ring, or an imidazole ring, and more preferably a pyridine ring.
Hydrogen atoms on the ring B ^40, from the point of viewpoint and solubility of durability is enhanced, an alkyl group having 1 to 20 carbon atoms, having 7 to 40 carbon atoms (hetero) aralkyl group or a C 3-20, It is preferably substituted with a (hetero) aryl group.
The hydrogen atom on ring B ⁴⁰ is preferably not substituted from the viewpoint of easy production.
Since the hydrogen atom on the ring B ⁴⁰ is likely to generate excitons when used as an organic electroluminescent device, a phenyl group or a naphthyl group which may have a substituent may be used from the viewpoint of increasing the luminous efficiency. It is preferably replaced with. The substituent that the phenyl group or the naphthyl group may have is preferably a substituent selected from the above-mentioned Substituent Group Z.

Ring B ⁴⁰ is preferably a quinoline ring, an isoquinoline ring, a quinazoline ring, a quinoxaline ring, an azatriphenylene ring, or a carboline ring from the viewpoint of increasing the luminous efficiency because excitons are easily generated on the assist dopant. .. Of these, a quinoline ring, an isoquinoline ring, and a quinazoline ring are more preferable in terms of durability and red emission.
A more preferred ^{substituent of ring B 40} is an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms which may be substituted with an alkyl group having 1 to 20 carbon atoms. Here, the aryl group having 6 to 20 carbon atoms is a group in which a plurality of monocyclic, bicyclic condensed rings, tricyclic condensed rings, monocyclic, dicyclic fused rings, or tricyclic condensed rings are linked.

A light-emitting dopant in the light-emitting layer which is an embodiment of the present invention, compound Examples of the compound represented by the formula (40), R ⁴⁴ is a phenyl group which may have a substituent group, i.e., the following formula It is preferably the compound represented by (40-1).

In the above ^{^{^{formulas, R 41, R 42, R}}} 43, a40, b40, c40, L 1, m40 is, ^R 41 in formula ^{^{(40), R 42, R}} 43, a40, b40, c40, and L 1, m40 Each is synonymous.
R ⁴⁵ has the same meaning as ^{R ^43,} ^{R 43} and ^{R 45} may be different even in the same. When a ^{plurality of R 43} and R ⁴⁵ exist, they may be the same or different from each other.
d40 is an integer from 0 to 5.

From ^{the viewpoint of durability, R 43} and R ⁴⁵ have an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, an arylamino group having 6 to 20 carbon atoms, or an arylamino group having 3 to 30 carbon atoms. It is preferably an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, or a (hetero) aryl group having 3 to 20 carbon atoms. , An alkyl group having 1 to 20 carbon atoms or an aralkyl group having 7 to 40 carbon atoms is more preferable.
The ^{substituent that R 43} and R ⁴⁵ may further have is preferably a substituent selected from the substituent group Z.

C40 and d40 are preferably 0 from the viewpoint of easy production, preferably 1 or 2 from the viewpoint of enhancing durability and solubility, and further preferably 1. b40 is preferably 0 from the viewpoint of easy production, and preferably 1 from the viewpoint of enhancing solubility.

The light emitting dopant represented by the formula (40) contained in the light emitting layer according to one embodiment of the present invention ^{preferably has a structure in which a40 is 2 or more and adjacent R 41s} are bonded to each other to form a fluorene ring. Among them, the compound represented by the following formula (40-2) is preferable.

In the above ^formula, ^{R 42 ~ R 44, b40,} c40, L 1, m40 are each the ^{^{R 42 ~ R 44, b40,}} c40, L 1, m40 synonymous in the formula (40).
R ⁵⁴ to R ⁵⁶ are substituents. When a ^{plurality of R 54} to R ⁵⁶ exist, they may be the same or different from each other.
i40 is an integer from 0 to 4.

R ⁵⁴ is a ^{substituent that substitutes for R 51} ^{when R 51} is a phenyl group, and is preferably a substituent selected from the substituent group Z. R ⁵⁴ is more preferably an aromatic hydrocarbon group having 6 to 30 carbon atoms, which may be substituted with an alkyl group having 1 to 20 carbon atoms and an alkyl group having 1 to 20 carbon atoms. Here, the aromatic hydrocarbon group having 6 to 30 carbon atoms is a monocyclic, 2 to 4 ring fused ring, or a group in which a plurality of monocyclic or 2 to 4 ring fused rings are linked. R ⁵⁴ is more preferably an alkyl group having 1 to 20 carbon atoms, and even more preferably an alkyl group having 1 to 8 carbon atoms.

R ^55, ^{R 56} ^is a substituent in which a part or ^{R 41} in ^{R 41} is substituted on ^{R 41} when there was a methyl group, preferably each independently, an alkyl group having 1 to 20 carbon atoms, carbon atoms It may be substituted with an alkyl group having 1 to 20 carbon atoms, an aromatic hydrocarbon group having 6 to 30 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms. It is an aromatic hydrocarbon group having 6 to 30 carbon atoms. Here, the aromatic hydrocarbon group having 6 to 30 carbon atoms is a monocyclic, 2 to 4 ring fused ring, or a group in which a plurality of monocyclic or 2 to 4 ring fused rings are linked. R ⁵⁵ and R ⁵⁶ are more preferably aromatic hydrocarbon groups having 6 or 12 carbon atoms which may be substituted with an alkyl group having 1 to 20 carbon atoms or an alkyl group having 1 to 20 carbon atoms. More preferably, it is an alkyl group having 1 to 8 carbon atoms or an aromatic hydrocarbon group having 6 carbon atoms which may be substituted with an alkyl group having 1 to 8 carbon atoms. Here, the aromatic hydrocarbon structure having 6 carbon atoms has a benzene structure, and the aromatic hydrocarbon structure having 12 carbon atoms has a biphenyl structure.

Specific examples of preferable alkyl groups in R ⁵⁴ to R ⁵⁶ include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-octyl group, isopropyl group and isobutyl. Examples thereof include a group, an isopentyl group, a t-butyl group, a cyclohexyl group, a 2-ethylhexyl group and the like.

Specific examples of preferable aromatic hydrocarbon groups in R ⁵⁴ to R ⁵⁶ include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzpyrene ring, a chrysene ring, a triphenylene ring, and a fluorantene ring. , Biphenyl group, terphenyl group and other monovalent groups.

Specific examples of the preferred alkoxy group in R ⁵⁴ to R ⁵⁶ include a methoxy group, an ethoxy group, a propyloxy group, an isopropyloxy group, a hexyloxy group, a cyclohexyloxy group, an octadecyloxy group and the like.

The compound that becomes the light emitting dopant represented by the formula (40-1) contained in the light emitting layer which is one form of the present invention is more preferably the compound represented by the following formula (40-3).

In the above ^{^{^{formulas, R 42, R 43, R}}} 45, b40, c40, d40, L 1, m40 is, ^R 42 in the formula ^{^{(40-1), R 43, R}} 45, b40, c40, d40, L 1, It is synonymous with m40.
^R ⁵⁴ ~ R 56, i40 are each synonymous with ^R 54 ^~ ^R 56, i40 in Equation (40-2).

Hereinafter, preferred specific examples of the compound represented by the formula (40), which is a light emitting dopant contained in the light emitting layer, which is one embodiment of the present invention other than those shown in the examples, will be shown, but the present invention is limited thereto. It's not a thing.

[Hole transport layer]
The hole transport layer of the organic electroluminescent device of the present invention (hereinafter, may be referred to as “hole transport layer of the present embodiment”) is preferably a material containing a partial structure A of the polymer of the present embodiment described above. Include as.
The hole transport layer of the present embodiment may contain one type of the polymer of the present embodiment, or may contain two or more types in any combination and in any ratio.

The content of the polymer of the present embodiment in the hole transport layer of the present embodiment is usually 1 to 100% by weight, preferably 5 to 100% by weight, and more preferably 10 to 100% by weight. The above range is preferable because the charge transportability of the hole transport layer of the present embodiment is improved, the drive voltage is reduced, and the drive stability is improved.

When the polymer of the present embodiment is not 100% by weight in the hole transport layer of the present embodiment, examples of the components constituting the hole transport layer of the present embodiment include hole transporting compounds described later. Be done.

Since the organic electroluminescent device can be easily manufactured, the polymer of the present embodiment is preferably used for the hole transport layer of the present embodiment formed by the wet film forming method. The method of forming the hole transport layer by the wet film formation method and the like will be described later.

[Composition for forming a hole transport layer]
The hole transport layer forming composition for forming the hole transport layer of the present embodiment by the wet film forming method contains the polymer of the present embodiment. The composition for forming a hole transport layer of the present embodiment may contain one kind of the above polymer, or may contain two or more kinds in any combination and any ratio. ..

[Polymer content]
The content of the polymer in the composition for forming a hole transport layer of the present embodiment is usually 0.01 to 70% by weight, preferably 0.1 to 60% by weight, and more preferably 0.5 to 50% by weight. By weight%.
When it is within the above range, defects are unlikely to occur in the formed hole transport layer, and uneven film thickness is unlikely to occur, which is preferable.
The composition for forming a hole transport layer of the present embodiment may contain a solvent or the like in addition to the above polymer.

[solvent]
The composition for forming a hole transport layer of the present embodiment usually contains a solvent. The solvent is preferably one that dissolves the above polymer. Specifically, a solvent that dissolves the polymer in an amount of usually 0.05% by weight or more, preferably 0.5% by weight or more, and more preferably 1% by weight or more at room temperature is preferable.

Specific examples of the solvent include aromatic solvents such as toluene, xylene, mesityrene and cyclohexylbenzene; halogen-containing solvents such as 1,2-dichloroethane, chlorobenzene and o-dichlorobenzene; ethylene glycol dimethyl ether, ethylene glycol diethyl ether and propylene. Aliper ethers such as glycol-1-monomethyl ether acetate (PGMEA), 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetol, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, Ether-based solvents such as aromatic ethers such as 2,3-dimethylanisole and 2,4-dimethylanisole; aliphatic ester-based solvents such as ethyl acetate, n-butyl acetate, ethyl lactate and n-butyl lactate; phenyl acetate, Ester-based solvents such as phenyl propionate, methyl benzoate, ethyl benzoate, isopropyl benzoate, propyl benzoate, n-butyl benzoate and other aromatic esters; Examples thereof include organic solvents used in the composition for forming a hole transport layer and the composition for forming a hole transport layer.

One type of solvent may be used, or two or more types may be used in any combination and in any ratio.

Among them, as the solvent contained in the composition for forming a hole transport layer of the present embodiment, the surface tension at 20 ° C. is usually less than 40 dyn / cm, preferably 36 dyn / cm or less, more preferably 33 dyn / cm or less. Certain solvents are preferred.

When a coating film is formed by a wet film forming method using the composition for forming a hole transport layer of the present embodiment and the polymer is crosslinked to form a hole transport layer, the affinity between the solvent and the substrate is high. Is preferable. This is because the uniformity of the film quality greatly affects the uniformity and stability of the light emission of the organic electroluminescent device. Therefore, the composition for forming a hole transport layer used in the wet film forming method is required to have a low surface tension so that a uniform coating film having higher leveling property can be formed. Therefore, by using a solvent having a low surface tension as described above, a uniform layer containing the polymer can be formed, and a uniform crosslinked layer can be formed, which is preferable.

Specific examples of the low surface tension solvent include the above-mentioned aromatic solvents such as toluene, xylene, mesityrene and cyclohexylbenzene, aromatic ester solvents such as ethyl benzoate, aromatic ether solvents such as anisole, and trifluoro. Examples thereof include methoxyanisole, pentafluoromethoxybenzene, 3- (trifluoromethyl) anisole, and ethyl (pentafluorobenzoate).

On the other hand, as the solvent contained in the composition for forming a hole transport layer of the present embodiment, a solvent having a vapor pressure at 25 ° C. of usually 10 mmHg or less, preferably 5 mmHg or less, and usually 0.1 mmHg or more is used. preferable. By using such a solvent, a composition for forming a hole transport layer suitable for a process of producing a hole transport layer by a wet film forming method and suitable for the properties of the polymer of the present embodiment is prepared. Can be done.

In order to obtain a more uniform film, it is preferable that the solvent evaporates at an appropriate rate from the liquid film immediately after the film formation. Therefore, as described above, the boiling point of the solvent used is usually 80 ° C. or higher, preferably 100 ° C. or higher, more preferably 120 ° C. or higher, usually 350 ° C. or lower, preferably 300 ° C. or lower, more preferably 280 ° C. or lower. Is.
Specific examples of such a solvent include the above-mentioned aromatic solvents such as mesitylene and cyclohexylbenzene, aromatic ether solvents and aromatic ester solvents.

Moisture may cause performance deterioration of the organic electroluminescent element, and in particular, it may promote a decrease in brightness during continuous driving. Therefore, in order to reduce the water content remaining during the wet film formation as much as possible, among the above-mentioned solvents, those having a water solubility at 25 ° C. of 1% by weight or less are preferable, and those having a solubility of 0.1% by weight or less are preferable. Is more preferable.

The content of the solvent contained in the composition for forming a hole transport layer of the present embodiment is usually 10% by weight or more, preferably 30% by weight or more, and particularly preferably 50% by weight or more. When the content of the solvent is at least the above lower limit, the flatness and uniformity of the formed layer can be improved.

[Electron accepting compound]
The composition for forming a hole transport layer of the present embodiment may further contain an electron-accepting compound from the viewpoint of reducing resistance.
As the electron-accepting compound, a compound having an oxidizing power and an ability to accept one electron from the above polymer is preferable. Specifically, a compound having an electron affinity of 4 eV or more is preferable, and a compound having an electron affinity of 5 eV or more is more preferable.

Examples of such an electron-accepting compound include a triarylboron compound, a metal halide, a Lewis acid, an organic acid, an onium salt, a salt of an arylamine and a metal halide, and a salt of an arylamine and a Lewis acid. Examples thereof include one kind or two or more kinds of compounds selected from the group consisting of two or more kinds.

Specifically, onium salts substituted with organic groups such as 4-isopropyl-4'-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate, triphenylsulfonium tetrafluoroborate (International Publication No. 2005/089024), ( International Publication No. 2017/164268); High valence inorganic compounds such as iron chloride (III) (Japanese Patent Laid-Open No. 11-251067), ammonium peroxodisulfate; cyano compounds such as tetracyanoethylene; tris (pentafluorophenyl) Examples include aromatic boron compounds such as borane (Japanese Patent Laid-Open No. 2003-31365); fullerene derivatives, iodine and the like.

The composition for forming a hole transport layer of the present embodiment may contain one kind of the above-mentioned electron-accepting compound alone, or may contain two or more kinds in any combination and ratio. good.

When the composition for forming a hole transport layer of the present embodiment contains an electron-accepting compound, the content of the electron-accepting compound is usually 0.0005% by weight or more, preferably 0.001% by weight or more, and is usually used. It is 20% by weight or less, preferably 10% by weight or less.
The ratio of the electron-accepting compound to the polymer in the hole transport layer forming composition is usually 0.5% by weight or more, preferably 1% by weight or more, more preferably 3% by weight or more, and usually 80% by weight. % Or less, preferably 60% by weight or less, more preferably 40% by weight or less.

When the content of the electron-accepting compound in the composition for forming a hole transport layer is at least the above lower limit, the electron acceptor accepts electrons from the polymer and the formed hole transport layer has low resistance, which is preferable. When the content of the electron-accepting compound in the composition for forming a hole transport layer is not more than the above upper limit, defects are unlikely to occur in the formed hole transport layer, and uneven film thickness is unlikely to occur, which is preferable.

[Cation radical compound]
The composition for forming a hole transport layer of the present embodiment may further contain a cationic radical compound.
As the cation radical compound, an ionic compound composed of a cation radical, which is a chemical species obtained by removing one electron from a hole transporting compound, and a counter anion is preferable. However, when the cation radical is derived from a hole-transporting polymer compound, the cation radical has a structure in which one electron is removed from the repeating unit of the polymer compound.

The cation radical is preferably a chemical species obtained by removing one electron from the hole transporting compound described later. A chemical species obtained by removing one electron from a preferable compound as a hole transporting compound is preferable from the viewpoints of amorphousness, visible light transmittance, heat resistance, solubility and the like.

Here, the cationic radical compound can be produced by mixing the hole transporting compound described later and the electron accepting compound described above. That is, by mixing the hole transporting compound and the electron accepting compound, electron transfer occurs from the hole transporting compound to the electron accepting compound, and the hole transporting compound is composed of a cationic radical and a counter anion. A cationic ion compound is produced.

When the composition for forming a hole transport layer of the present embodiment contains a cation radical compound, the content of the cation radical compound in the composition for forming a hole transport layer is usually 0.0005% by weight or more, preferably 0. It is 001% by weight or more, usually 40% by weight or less, preferably 20% by weight or less. When the content of the cationic radical compound is at least the lower limit, the formed hole transport layer has low resistance, which is preferable. When the content of the cationic radical compound is not more than the upper limit, defects are less likely to occur in the formed hole transport layer, and uneven film thickness is less likely to occur, which is preferable.

In the composition for forming a hole transport layer of the present embodiment, in addition to the above-mentioned components, the components contained in the composition for forming a hole injection layer and the composition for forming a hole transport layer, which will be described later, are contained in the composition described below. It may be contained in.

[Light emitting layer]
The light emitting layer of the organic electroluminescent device of the present invention (hereinafter, may be referred to as “light emitting layer of the present embodiment”) preferably contains the above-mentioned low molecular weight compound of the present embodiment as a partial structure A-containing material.
The light emitting layer of the present embodiment may contain one kind of the small molecule compound of the present embodiment, or may contain two or more kinds in any combination and any ratio.

The light emitting layer of the present embodiment contains at least the low molecular weight compound of the present embodiment and the light emitting material, and the low molecular weight compound of the present embodiment functions as a host material of the light emitting material.
As the light emitting material, a phosphorescent light emitting material or a fluorescent light emitting material can be used.

The content of the light emitting material contained in the light emitting layer of the present invention is usually 0.1 to 50% by weight, preferably 0.2 to 40% by weight, and more preferably 0.5 to 35% by weight. When the content of the light emitting material is within the above range, high luminous efficiency can be obtained.

The content of the small molecule compound of the present embodiment in the light emitting layer of the present embodiment is usually 5% by weight or more, preferably 10% by weight or more, more preferably 20% by weight, as the content in the material other than the light emitting material. As described above, it is particularly preferably 30% by weight or more, usually 100% by weight or less, preferably 90% by weight or less, still more preferably 80% by weight or less, and particularly preferably 70% by weight or less. The above range is preferable because it is considered that the charge transportability of the light emitting layer of the present embodiment is improved, the driving voltage is reduced, and the driving stability is improved.

When the light emitting layer of the present embodiment contains a light emitting material and other components other than the small molecule compound of the present embodiment, examples of the other components include a charge transport material described later. The content of other components such as the charge transport material described later in the light emitting layer of the present embodiment is usually 0% by weight or more, preferably 10% by weight or more, more preferably 10% by weight or more, as the content in the material other than the light emitting material. It is 20% by weight or more, particularly preferably 30% by weight, usually 95% by weight or less, preferably 90% by weight or less, still more preferably 80% by weight or less, and particularly preferably 70% by weight or less. The above range is preferable because it is considered that the carrier balance of electrons and holes in the light emitting layer is good, the luminous efficiency is improved, the charge transportability is improved, the voltage is lowered, and the drive stability is improved.

Since the organic electroluminescent device can be easily manufactured, the small molecule compound of the present embodiment is preferably used for the light emitting layer of the present embodiment formed by the wet film formation method. The method of forming the light emitting layer by the wet film forming method will be described later.

[Composition for forming a light emitting layer]
The composition for forming a light emitting layer for forming the light emitting layer of the present embodiment by the wet film forming method contains the low molecular weight compound of the present embodiment. The composition for forming a light emitting layer of the present embodiment may contain one kind of the above-mentioned small molecule compound, or may contain two or more kinds in any combination and any ratio.

[Content of small molecule compounds]
The total content of solids such as the small molecule compound, the light emitting material, and the charge transport material in the composition for forming a light emitting layer of the present embodiment is usually 0.01 to 70% by weight, preferably 0.1 to 0.1. It is 60% by weight, more preferably 0.5 to 50% by weight.
When it is within the above range, defects are unlikely to occur in the formed light emitting layer, and uneven film thickness is unlikely to occur, which is preferable.
The composition for forming a light emitting layer of the present embodiment may contain a solvent or the like in addition to the components such as the small molecule compound, the light emitting material, and the charge transport material.

[solvent]
The composition for forming a light emitting layer of the present embodiment usually contains a solvent.

As the solvent, the same solvent as the solvent contained in the composition for forming a hole transport layer can be selected and used. The properties required for the solvent are similar, and so are the preferred solvents.

The amount of the solvent used is arbitrary as long as the effect of the present invention is not significantly impaired, but the content in the light emitting layer forming composition is preferably 1% by mass or more, more preferably 10% by mass or more, and particularly preferably 50. It is 9% by mass or more, preferably 99.99% by mass or less, more preferably 99.9% by mass or less, and particularly preferably 99% by mass or less.

[Phosphorescent layer]
When the light emitting layer of the present embodiment is a phosphorescent light emitting layer containing a phosphorescent light emitting material as a light emitting material, the following materials are preferable as the phosphorescent light emitting material.

<Phosphorescent material>
The phosphorescent material refers to a material that emits light from an excited triplet state. For example, a metal complex compound having Ir, Pt, Eu, etc. is a typical example, and a material containing a metal complex is preferable as the structure of the material.

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

[Compound represented by formula (201)]

In the formula (201), the ring A1 represents an aromatic hydrocarbon ring structure which may have a substituent or an aromatic heterocyclic structure which may have a substituent.
Ring A2 represents an aromatic heterocyclic structure which may have a substituent.
R ²⁰¹ and R ²⁰² are structures independently represented by the equation (202). “*” Represents a binding site with ring A1 or ring A2. R ²⁰¹ and R ²⁰² may be the same or different. When ^{there are a plurality of R 201} and R ²⁰² , they may be the same or different.
Ar ²⁰¹ and Ar ²⁰³ each independently represent an aromatic hydrocarbon structure which may have a substituent or an aromatic heterocyclic structure which may have a substituent.
Ar ²⁰² has an aromatic hydrocarbon structure which may have a substituent, an aromatic heterocyclic structure which may have a substituent, or an aliphatic hydrocarbon structure which may have a substituent. show.
Substituents bonded to ring A1, substituents bonded to ring A2, or substituents bonded to ring A1 and substituents bonded to ring A2 may be bonded to each other to form a ring.
B ^201- L ^200- B ²⁰² represents an anionic bidentate ligand. B ²⁰¹ and B ²⁰² each independently represent a carbon atom, an oxygen atom, or a nitrogen atom, and these atoms may be atoms constituting a ring. L ²⁰⁰ represents a single bond, or ^represents an atomic group together with ^{B 201} and ^{B 202} constituting the bidentate ligand. When ^{there are a plurality of B 201-} L ^200- B ²⁰² , they may be the same or different.
i1 and i2 independently represent integers of 0 or more and 12 or less.
i3 is an integer of 0 or more up to a number substitutable for ^{Ar 202.}
j1 is an integer of 0 or more up to a number substitutable for ^{Ar 201.}
k1 and k2 are independently integers of 0 or more, up to a number substitutable for rings A1 and A2, respectively.
m1 is an integer of 1 to 3.

Unless otherwise specified, as the above-mentioned substituent, a group selected from the following substituent group Z'is preferable.

<Substituent group Z'>
Aryl group: An alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms, further preferably an alkyl group having 1 to 8 carbon atoms, and particularly preferably an alkyl group having 1 to 6 carbon atoms. -Aalkoxy group: An alkoxy group having 1 to 20 carbon atoms, more preferably an alkoxy group having 1 to 12 carbon atoms, further preferably an alkoxy group having 1 to 6 carbon atoms, and an aryloxy group: preferably 6 to 20 carbon atoms. Aryloxy group, more preferably an aryloxy group having 6 to 14 carbon atoms, further preferably an aryloxy group having 6 to 12 carbon atoms, particularly preferably an aryloxy group having 6 carbon atoms or a heteroaryloxy group: preferably carbon. Heteroaryloxy group having 3 to 20, more preferably heteroaryloxy group / alkylamino group having 3 to 12 carbon atoms: preferably an alkylamino group having 1 to 20 carbon atoms, more preferably an alkyl having 1 to 12 carbon atoms. Amino group / arylamino group: preferably an arylamino group having 6 to 36 carbon atoms, more preferably an arylamino group / aralkyl group having 6 to 24 carbon atoms: preferably an aralkyl group having 7 to 40 carbon atoms, more preferably carbon. Aralkyl groups having 7 to 18 carbon atoms, more preferably arylyl groups having 7 to 12 carbon atoms / heteroaralkyl groups: preferably heteroaralkyl groups having 4 to 40 carbon atoms, more preferably heteroaralkyl groups having 4 to 18 carbon atoms / alkenyl. Group: An alkenyl group having 2 to 20 carbon atoms, more preferably an alkenyl group having 2 to 12 carbon atoms, further preferably an alkenyl group having 2 to 8 carbon atoms, and particularly preferably an alkenyl group having 2 to 6 carbon atoms, alkynyl. Group: preferably an alkynyl group having 2 to 20 carbon atoms, more preferably an alkynyl group / aryl group having 2 to 12 carbon atoms: preferably an aryl group having 6 to 30 carbon atoms, more preferably an aryl group having 6 to 24 carbon atoms. An aryl group having 6 to 18 carbon atoms, particularly preferably an aryl group having 6 to 14 carbon atoms or a heteroaryl group: preferably a heteroaryl group having 3 to 30 carbon atoms, more preferably having 3 to 24 carbon atoms. Heteroaryl groups, more preferably heteroaryl groups having 3 to 18 carbon atoms, particularly preferably heteroaryl groups having 3 to 14 carbon atoms / alkylsilyl groups: preferably alkylsilyl groups having 1 to 20 carbon atoms. , More preferably an alkylsilyl group / arylsilyl group having an alkyl group having 1 to 12 carbon atoms: preferably an arylcy having an aryl group having 6 to 20 carbon atoms. Arylsilyl group / alkylcarbonyl group having 6 to 14 carbon atoms, more preferably an aryl group: preferably an alkylcarbonyl group having 2 to 20 carbon atoms, an arylcarbonyl group: preferably an aryl having 7 to 20 carbon atoms. Substituents having a carbonyl group or more may have one or more hydrogen atoms replaced with fluorine atoms, or one or more hydrogen atoms may have been replaced with heavy hydrogen atoms.
Unless otherwise specified, the aryl group is an aromatic hydrocarbon group and the heteroaryl group is an aromatic heterocyclic group.
-Hydrogen atom, deuterium atom, fluorine atom, cyano group, or -SF ₅

(Preferable group in substituent group Z')
Of the above substituent group Z',
Preferably, an alkyl group, an alkoxy group, an aryloxy group, an arylamino group, an aralkyl group, an alkenyl group, an aryl group, a heteroaryl group, an alkylsilyl group, an arylsilyl group, and one or more hydrogen atoms of these groups are present. A group replaced by a fluorine atom, a fluorine atom, a cyano group, -SF ₅ ,
More preferably, an alkyl group, an alkoxy group, an aryloxy group, an arylamino group, an aralkyl group, an alkenyl group, an aryl group, a heteroaryl group, and a group in which one or more hydrogen atoms of these groups are replaced with fluorine atoms. , Fluorine atom, cyano group, -SF ₅ ,
More preferably, it is an alkyl group, an alkoxy group, an aryloxy group, an arylamino group, an aralkyl group, an alkenyl group, an aryl group or a heteroaryl group.
Particularly preferred are an alkyl group, an arylamino group, an aralkyl group, an alkenyl group, an aryl group, and a heteroaryl group.
Most preferably, it is an alkyl group, an arylamino group, an aralkyl group, an aryl group, or a heteroaryl group.

(Substituent substituting for Z')
These substituent group Z'may further have a substituent selected from the substituent group Z'as a substituent. The preferred group, the more preferable group, the more preferable group, the particularly preferable group, and the most preferable group of the substituents which may be possessed are the same as the preferable groups in the substituent group Z'.

<Ring A1>
Ring A1 represents an aromatic hydrocarbon ring structure which may have a substituent or an aromatic heterocyclic structure which may have a substituent.

The aromatic hydrocarbon ring of ring A1 is preferably an aromatic hydrocarbon ring having 6 to 30 carbon atoms. Specifically, a benzene ring, a naphthalene ring, an anthracene ring, a triphenylyl ring, an acenaphthene ring, a fluoranthene ring, and a fluorene ring are preferable.
As the aromatic heterocycle of ring A1, an aromatic heterocycle having 3 to 30 carbon atoms containing any of a nitrogen atom, an oxygen atom, and a sulfur atom as a heteroatom is preferable, and a furan ring and a benzofuran ring are more preferable. , Thiophene ring, benzothiophene ring.
The ring A1 is more preferably a benzene ring, a naphthalene ring, or a fluorene ring, particularly preferably a benzene ring or a fluorene ring, and most preferably a benzene ring.

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

The aromatic heterocycle of ring A2 is preferably an aromatic heterocycle having 3 to 30 carbon atoms, which contains any of a nitrogen atom, an oxygen atom, or a sulfur atom as a hetero atom. Specifically, pyridine ring, pyrimidine ring, pyrazine ring, triazine ring, imidazole ring, oxazole ring, thiazole ring, benzothiazole ring, benzoxazole ring, benzoimidazole ring, quinoline ring, isoquinoline ring, quinoxalin ring, quinazoline ring, Examples thereof include a naphthylidine ring and a 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 quinazoline ring and a quinazoline ring. Preferred are a pyridine ring, an imidazole ring, a benzothiazole ring, a quinoline ring, an isoquinoline ring, a quinazoline ring, and a quinazoline ring, and most preferably a pyridine ring, an imidazole ring, a benzothiazole ring, a quinoline ring, a quinazoline ring, and a quinazoline ring. be.

(Combination of ring A1 and ring A2)
As a preferable combination of ring A1 and ring A2, when expressed as (ring A1-ring A2), (benzene ring-pyridine ring), (benzene ring-quinoline ring), (benzene ring-quinoxaline ring), (benzene ring- Quinazoline ring), (benzene ring-imidazole ring), (benzene ring-benzothiazole ring).

(Substituents of ring A1 and ring A2)
The substituents that the rings A1 and A2 may have can be arbitrarily selected, but preferably one or a plurality of substituents selected from the substituent group Z'.

<Ar ²⁰¹ , Ar ²⁰² , Ar ²⁰³ >
Ar ²⁰¹ and Ar ²⁰³ each independently represent an aromatic hydrocarbon ring structure which may have a substituent or an aromatic heterocyclic structure which may have a substituent.
Ar ²⁰² has an aromatic hydrocarbon ring structure which may have a substituent, an aromatic heterocyclic structure which may have a substituent, or an aliphatic hydrocarbon structure which may have a substituent. Represents.

(Aromatic hydrocarbon rings of ^{Ar 201} , Ar ²⁰² , Ar ²⁰³⁾
When ^{any one of Ar 201} , Ar ²⁰² , and Ar ²⁰³ has an aromatic hydrocarbon structure which may have a substituent, the aromatic hydrocarbon structure is preferably an aromatic hydrocarbon having 6 to 30 carbon atoms. It is a ring. Specific examples thereof include a benzene ring, a naphthalene ring, an anthracene ring, a triphenylyl ring, an acenaphthene ring, a fluoranthene ring and a fluorene ring, more preferably a benzene ring, a naphthalene ring and a fluorene ring, and most preferably a benzene ring. ..

(9,9'of Fluorene)
When any of Ar ²⁰¹ , Ar ²⁰² , and Ar ^{203 is} a fluorene ring which may have a substituent, the 9-position and 9'-position of the fluorene ring have a substituent or are bonded to an adjacent structure. Is preferable.

(О-, m-phenylene)
When ^{either Ar 201} or Ar ^{202 is} a benzene ring which may have a substituent, at least one benzene ring is preferably bonded to an adjacent structure at the ortho-position or the meta-position, and at least one. It is more preferable that one benzene ring is bonded to an adjacent structure at the meta position.

(Aromatic heterocycles of ^{Ar 201} , Ar ²⁰² , Ar ²⁰³⁾
When ^{any one of Ar 201} , Ar ²⁰² , and Ar ^{203 is} an aromatic heterocyclic structure which may have a substituent, the aromatic heterocyclic structure is preferably a nitrogen atom, an oxygen atom, or a heteroatom as a heteroatom. It is an aromatic heterocycle containing any of the sulfur atoms and having 3 to 30 carbon atoms. Specifically, pyridine ring, pyrimidine ring, pyrazine ring, triazine ring, imidazole ring, oxazole ring, thiazole ring, benzothiazole ring, benzoxazole ring, benzimidazole ring, quinoline ring, isoquinoline ring, quinoxalin ring, quinazoline ring, Examples thereof include a naphthylidine ring, a phenanthridin ring, a carbazole ring, a dibenzofuran ring and a dibenzothiophene ring, and more preferably a pyridine ring, a pyrimidine ring, a triazine ring, a carbazole ring, a dibenzofuran ring and a dibenzothiophene ring.

(N position of carbazole)
If any of Ar ²⁰¹ , Ar ²⁰² , and Ar ^{203 is} a carbazole ring which may have a substituent, the N-position of the carbazole ring may have a substituent or be bonded to an adjacent structure. preferable.

(Alphatic hydrocarbon of ^{Ar 202)}
When Ar ²⁰² is an aliphatic hydrocarbon structure which may have a substituent, it is an aliphatic hydrocarbon structure having a straight chain, a branched chain, or a cyclic structure, preferably having 1 or more and 24 or less carbon atoms. Yes, more preferably the carbon number is 1 or more and 12 or less, and more preferably the carbon number is 1 or more and 8 or less.

<I1, i2, i3, j1, k1, k2>
(Preferable range of i1 and i2)
i1 represents an integer of 0 to 12, preferably an integer of 1 to 12, more preferably 1 to 8, and even more preferably an integer of 1 to 6. Within this range, the solubility and charge transportability are expected to be improved.

(Preferable range of i3)
i3 preferably represents an integer of 0 to 5, more preferably 0 to 2, more preferably 0 or 1.

(Preferable range of j1)
j1 preferably represents an integer of 0 to 2, and is more preferably 0 or 1.

(Preferable range of k1 and k2)
k1 and k2 preferably represent an integer of 0 to 3, more preferably 1 to 3, more preferably 1 or 2, and particularly preferably 1.

<Preferable substituents of ^{Ar 201} , Ar ²⁰² , Ar ^203>
The ^{substituents that Ar 201} , Ar ²⁰² , and Ar ²⁰³ may have can be arbitrarily selected, but preferably one or a plurality of substituents selected from the substituent group Z'. The preferred group is also the same as that of the substituent group Z', but more preferably a hydrogen atom, an alkyl group or an aryl group, particularly preferably a hydrogen atom or an alkyl group, and most preferably an unsubstituted (hydrogen atom). be.

<Preferable structure of formula (201)>
Among the compounds represented by the formula (201), compounds having the following structures are preferable.

(Phenylene connection type)
A structure having a group in which benzene rings are linked.
That is, Ar ²⁰¹ is bonded to a benzene ring structure, i1 is 1 to 6, and at least one of the benzene rings is bonded to an adjacent structure at the ortho-position or the meta-position.
With this structure, it is expected that the solubility is improved and the charge transportability is improved.

((Phenylene)-(Aralkill)-(Alkyl))
A structure having an aromatic hydrocarbon group or an aromatic heterocyclic group having an alkyl group or an aralkyl group bonded to the ring A1 or the ring A2.
That is, Ar ²⁰¹ is an aromatic hydrocarbon structure or an aromatic heterocyclic structure, i1 is 1 to 6, Ar ²⁰² is an aliphatic hydrocarbon structure, i2 is 1 to 12, preferably 3 to 8, and Ar ²⁰³ is a benzene ring structure. , I3 is 0 or 1.
Preferably, Ar ²⁰¹ has the aromatic hydrocarbon structure, more preferably a structure in which 1 to 5 benzene rings are linked, and more preferably one benzene ring.
With this structure, it is expected that the solubility is improved and the charge transportability is improved.

(Dendron)
A structure in which dendron is bound to ring A1 or ring A2.
For example, Ar and Ar ²⁰² have a benzene ring structure, Ar ²⁰³ has a biphenyl or terphenyl structure, i1 and i2 have 1 to 6, i3 has 2, and j has 2.
With this structure, it is expected that the solubility is improved and the charge transportability is improved.

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

The ^{structure represented by B 201-} L ^200- B ²⁰² is preferably a structure represented by the following formula (203) or (204).

(In formula (203), R ²¹¹ , R ²¹² , and R ²¹³ represent substituents.)

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

<Phosphorescent material represented by the preferred formula (201)>
The phosphorescent material represented by the formula (201) is not particularly limited, and specific examples thereof include the following structures. In the following, "Ph" represents a "phenyl group" and "Me" represents a "methyl group".

[Compound represented by formula (205)]

In formula (205), M ² represents a metal. T represents a carbon atom or a nitrogen atom. R ⁹² to R ⁹⁵ each independently represent a substituent. However, when T is a nitrogen atom, there are no ^{R 94} and R ^95.

In formula (205), M ² represents a metal. As a specific example, the above-mentioned metal can be mentioned as a metal selected from the 7th to 11th groups of the periodic table. Of these, ruthenium, rhodium, palladium, silver, renium, osmium, iridium, platinum or gold are preferable, and divalent metals such as platinum and palladium are particularly preferable.

In formula (205), R ⁹² and R ⁹³ are independently hydrogen atom, halogen atom, alkyl group, aralkyl group, alkenyl group, cyano group, amino group, acyl group, alkoxycarbonyl group, carboxyl group and alkoxy group, respectively. , Alkylamino group, aralkylamino group, haloalkyl group, hydroxyl group, aryloxy group, aromatic hydrocarbon group or aromatic heterocyclic group.

When T is a carbon atom, R ⁹⁴ and R ⁹⁵ independently represent substituents represented by the same examples as ^{R 92} and R ^{93, respectively.} When T is a nitrogen atom, there is no ^{R 94} or R ^{95 that directly binds to the T.}
R ⁹² to R ⁹⁵ may further have a substituent. The substituent can be the above-mentioned substituent.
Any two or more groups of R ⁹² to R ⁹⁵ may be connected to each other to form a ring.

<Molecular weight of phosphorescent material>
The molecular weight of the phosphorescent material is preferably 5000 or less, more preferably 4000 or less, particularly preferably 3000 or less, usually 800 or more, preferably 1000 or more, still more preferably 1200 or more. Within this molecular weight range, it is considered that the phosphorescent materials do not aggregate and are uniformly mixed with the charge transport material, so that a light emitting layer having high luminous efficiency can be obtained.

The molecular weight of the phosphorescent material is high in Tg, melting point, decomposition temperature, etc., and the phosphorescent material and the formed light emitting layer are excellent in heat resistance, and the film quality due to gas generation, recrystallization, molecular migration, etc. It is preferable that it is large in that it is unlikely that a decrease in the concentration of impurities or an increase in the concentration of impurities due to thermal decomposition of the material will occur. On the other hand, the molecular weight of the phosphorescent material is preferably small in that the organic compound can be easily purified.

[Host material for phosphorescent layer]
The light emitting layer of the present embodiment contains the low molecular weight compound of the present embodiment as a host material, but when the light emitting layer is a phosphorescent light emitting layer, it is preferable to include the following materials as other host materials.

The host material of the light emitting layer is a material having a skeleton excellent in charge transportability, and is preferably selected from an electron transporting material, a hole transporting material, and a bipolar material capable of transporting both electrons and holes.

(Skeleton with excellent charge transport)
Specific examples of the skeleton having excellent charge transport properties include an aromatic structure, an aromatic amine structure, a triarylamine structure, a dibenzofuran structure, a naphthalene structure, a phenanthrene structure, a phthalocyanine structure, a porphyrin structure, a thiophene structure, and a benzylphenyl structure. Examples thereof include a fluorene structure, a quinacridone structure, a triphenylene structure, a carbazole structure, a pyrene structure, an anthracene structure, a phenanthrene structure, a quinoline structure, a pyridine structure, a pyrimidine structure, a triazine structure, an oxadiazole structure or an imidazole structure.

(Electronic transportable material)
As the electron transporting material, a compound having a pyridine structure, a pyrimidine structure, and a triazine structure is more preferable, and a compound having a pyrimidine structure and a triazine structure is preferable from the viewpoint of being a material having excellent electron transportability and a relatively stable structure. Is more preferable.

(Hole transport material)
The hole transporting material is a compound having a structure excellent in hole transporting property, and among the central skeletons having excellent hole transporting property, a carbazole structure, a dibenzofuran structure, a triarylamine structure, a naphthalene structure, a phenanthrene structure or The pyrene structure is preferable as a structure having excellent hole transportability, and a carbazole structure, a dibenzofuran structure or a triarylamine structure is more preferable.

(Condensed ring structure of 3 or more rings)
The host material of the light emitting layer preferably has a condensed ring structure of 3 or more rings, and is further preferably a compound having 2 or more condensed ring structures of 3 or more rings or a compound having at least one condensed ring structure of 5 or more rings. preferable. By using these compounds, the rigidity of the molecule is increased, and the effect of suppressing the degree of molecular motion in response to heat can be easily obtained. Further, it is preferable that the condensed ring having 3 or more rings and the condensed ring having 5 or more rings have an aromatic hydrocarbon ring or an aromatic heterocycle in terms of charge transportability and material durability.

Specific examples of the fused ring structure having three or more rings include anthracene structure, phenanthrene structure, pyrene structure, chrysene structure, naphthacene structure, triphenylene structure, fluorene structure, benzofluorene structure, indenofluorene structure, and indolofluorene structure. Examples thereof include a carbazole structure, an indenocarbazole structure, an indolocarbazole structure, a dibenzofuran structure, and a dibenzothiophene structure. From the viewpoint of charge transportability and solubility, at least one selected from the group consisting of phenanthrene structure, fluorene structure, indenofluorene structure, carbazole structure, indenocarbazole structure, indolocarbazole structure, dibenzofuran structure and dibenzothiophene structure is selected. preferable. A carbazole structure or an indolocarbazole structure is more preferable from the viewpoint of resistance to electric charge.

From the viewpoint of durability against electric charge of the organic electroluminescent device, it is preferable that at least one of the host materials of the light emitting layer is a material having a pyrimidine skeleton or a triazine skeleton.

(Molecular weight range)
The host material of the light emitting layer is preferably a polymer material from the viewpoint of excellent flexibility. A light emitting layer formed by using a material having excellent flexibility is preferable as a light emitting layer of an organic electroluminescent element formed on a flexible substrate. When the host material contained 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 more preferably 10,000 or more. It is 100,000 or less.

The host material of the light emitting layer is a small molecule in terms of ease of synthesis and purification, ease of designing electron transport performance and hole transport performance, and ease of viscosity adjustment when dissolved in a solvent. Is preferable. When the host material contained in the light emitting layer is a low molecular weight material, the molecular weight is preferably 5,000 or less, more preferably 4,000 or less, particularly preferably 3,000 or less, and most preferably 2,. It is 000 or less, usually 300 or more, preferably 350 or more, and more preferably 400 or more.

[Fluorescent light emitting layer]
When the light emitting layer of the present embodiment is a fluorescent light emitting layer, it is preferable that the light emitting layer is a blue fluorescent light emitting layer using the following blue fluorescent light emitting material as the fluorescent light emitting material.

<Blue fluorescent light emitting material>
The light emitting material for the blue fluorescent light emitting layer is not particularly limited, but a compound represented by the following formula (211) is preferable.

In the above formula (211), Ar ²⁴¹ represents an aromatic hydrocarbon condensed ring structure which may have a substituent. Ar ²⁴² and Ar ²⁴³ represent an alkyl group which may independently have a substituent, an aromatic hydrocarbon group, or a group to which these are bonded. n41 is an integer of 1 to 4.

Ar ²⁴¹ preferably represents an aromatic hydrocarbon condensed ring structure having 10 to 30 carbon atoms. Specific structures include naphthalene ring, acenaphthene ring, fluorene ring, anthracene ring, phenatren ring, fluoranthene ring, pyrene ring, tetracene ring, chrysene ring, perylene ring and the like. More preferably, it has an aromatic hydrocarbon condensed ring structure having 12 to 20 carbon atoms. Specific structures include an acenaphthene ring, a fluorene ring, an anthracene ring, a phenatren ring, a fluoranthene ring, a pyrene ring, a tetracene ring, a chrysene ring, and a perylene ring. More preferably, it has an aromatic hydrocarbon condensed ring structure having 16 to 18 carbon atoms. Specific structures include a fluoranthene ring, a pyrene ring, and a chrysene ring.

N41 is an integer of 1 to 4, preferably 1 to 3, more preferably 1 to 2, and most preferably 2.

(Substituents of ^{Ar 241} and Ar ²⁴² and Ar ²⁴³⁾
The ^{substituents that Ar 241} , Ar ²⁴² , and Ar ²⁴³ may have are preferably a group selected from the substituent group Z', more preferably a hydrocarbon group contained in the substituent group Z', and further. It is preferably a hydrocarbon group among the groups preferred as the substituent group Z'.

[Host material for blue fluorescent light emitting layer]
In the light emitting layer of the present embodiment, the small molecule compound of the present embodiment is used as the host material of the light emitting material, but when the blue fluorescent light emitting material is used, the following materials are preferable as the other host materials.

The host material for the blue fluorescent light emitting layer is not particularly limited, but a compound represented by the following formula (212) is preferable.

In the above formula (212), R ²⁴¹ and R ²⁴² have structures independently represented by the following formula (213). ^R243 represents a substituent. When ^{there are a plurality of R 243s} , they may be the same or different. n43 is an integer from 0 to 8.

In the above formula (213), Ar ²⁴⁴ and Ar ²⁴⁵ independently represent an aromatic hydrocarbon structure which may have a substituent or a heteroaromatic ring structure which may have a substituent. When ^{a plurality of Ar 244} and Ar ²⁴⁵ exist, they may be the same or different. n44 is an integer from 1 to 5. n45 is an integer from 0 to 5.

Ar ²⁴⁴ is preferably an aromatic hydrocarbon structure which is a monocyclic or condensed ring having 6 to 30 carbon atoms, which may have a substituent, and more preferably it may have a substituent. , An aromatic hydrocarbon structure which is a monocyclic or condensed ring having 6 to 12 carbon atoms.

Ar ²⁴⁵ preferably has an aromatic hydrocarbon structure which is a monocyclic or fused ring having 6 to 30 carbon atoms, which may have a substituent, or may have a substituent, which has 6 carbon atoms. It has an aromatic heterocyclic structure which is a fused ring of to 30 and more preferably has an aromatic hydrocarbon structure which is a monocyclic ring or a fused ring having 6 to 12 carbon atoms or which may have a substituent. It is an aromatic heterocyclic structure which is a fused ring having 12 carbon atoms which may have a substituent.

N44 is preferably an integer of 1 to 3, and more preferably 1 or 2. n45 is preferably 0 to 3, more preferably 0 to 2.

(Substituents of ^{R 243} , Ar ²⁴⁴ , Ar ²⁴⁵⁾
The substituents R ²⁴³ and Ar ²⁴⁴ and Ar ²⁴⁵ may have a substituent preferably a group selected from the substituent group Z', and more preferably a hydrocarbon contained in the substituent group Z'. It is a group, more preferably a hydrocarbon group among the groups preferred as the substituent group Z'.

(Molecular weight)
The molecular weight of the light emitting material for the blue fluorescent light emitting layer and its host material is preferably 5,000 or less, more preferably 4,000 or less, particularly preferably 3,000 or less, and most preferably 2,000 or less. , Usually 300 or more, preferably 350 or more, more preferably 400 or more.

[Organic electroluminescent device]
The organic electroluminescent device of the present embodiment is an organic electroluminescent device having an anode, a cathode, and an organic layer between the anode and the cathode on a substrate, and the organic layer is a hole transport layer and a hole transport layer. A partial structure A having a light emitting layer adjacent to the hole transport layer, and at least one of the materials contained in these hole transport layers and at least one of the materials contained in the light emitting layer have the same partial structure A. It is characterized by being a contained material.

The preferred embodiments of the hole transport layer of the present embodiment containing the partial structure A-containing material and the light emitting layer of the present embodiment containing the partial structure A-containing material are as described above.

As an example of the structure of the organic electroluminescent device of the present embodiment, FIG. 1 shows a schematic view (cross section) of a structural example of the organic electroluminescent device 10. In FIG. 1, 1 is a substrate, 2 is an anode, 3 is a hole injection layer, 4 is a hole transport layer, 5 is a light emitting layer, 6 is a hole blocking layer, 7 is an electron transport layer, and 8 is an electron injection layer. 9 represents each cathode.

Hereinafter, an example of an embodiment such as a layer structure of an organic electroluminescent device and a general forming method thereof will be described with reference to FIG.

In the present embodiment, the wet film forming method is a film forming method, that is, as a coating method, for example, a spin coating method, a dip coating method, a die coating method, a bar coating method, a blade coating method, a roll coating method, a spray coating method, and the like. A method of forming a film by adopting a wet film forming method such as a capillary coating method, an inkjet method, a nozzle printing method, a screen printing method, a gravure printing method, or a flexographic printing method, and drying the coating film. Among these film forming methods, a spin coating method, a spray coating method, an inkjet method, a nozzle printing method and the like are preferable.

[substrate]
The substrate 1 serves as a support for an organic electroluminescent element, and usually a quartz or glass plate, a metal plate, a metal foil, a plastic film, a sheet, or the like is used. Of these, a glass plate or a transparent synthetic resin plate such as polyester, polymethacrylate, polycarbonate, or polysulfone is preferable. The substrate is preferably made of a material having a high gas barrier property because the organic electroluminescent element is unlikely to be deteriorated by the outside air. Therefore, particularly when a material having a low gas barrier property 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 property.

[anode]
The anode 2 has a function of injecting holes into the layer on the light emitting layer 5 side.
The anode 2 is usually a metal such as aluminum, gold, silver, nickel, palladium, platinum; a metal oxide such as an oxide of indium and / or tin; a metal halide such as copper iodide; carbon black and poly (3). -Methylthiophene), polypyrrole, polyaniline and other conductive polymers.

The anode 2 is usually formed by a dry method such as a sputtering method or a vacuum vapor deposition method. When forming an anode using metal fine particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, conductive polymer fine powder, etc., disperse them in an appropriate binder resin solution. It can also be formed by applying it on a substrate. In the case of a conductive polymer, a thin film can be formed directly on the substrate by electrolytic polymerization, or an anode can be formed by applying the conductive polymer on the substrate (Appl. Phys. Lett., Volume 60, 2711 p., 1992).

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

The thickness of the anode 2 may be determined according to the required transparency, material, and the like. When particularly high transparency is required, a thickness having a visible light transmittance of 60% or more is preferable, and a thickness having a visible light transmittance of 80% or more is more preferable. The thickness of the anode 2 is usually 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less. When transparency is not required, the thickness of the anode 2 may be arbitrarily set according to the required strength and the like. In this case, the anode 2 may have the same thickness as the substrate.

When another layer is formed on the surface of the anode 2, impurities on the anode 2 are removed and the ionization potential thereof is formed by treating the surface of the anode 2 with ultraviolet rays / ozone, oxygen plasma, argon plasma, or the like. It is preferable to improve the hole injection property.

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

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

The hole injection layer may be formed by either a vacuum vapor deposition method or a wet film deposition method. In terms of excellent film forming property, it is preferably formed by a wet film forming method.

The hole injection layer 3 preferably contains a hole transporting compound, and more preferably contains a hole transporting compound and an electron accepting compound. Further, it is preferable to contain a cationic radical compound in the hole injection layer, and it is particularly preferable to contain a cationic radical compound and a hole transporting compound.

The general method for forming the hole injection layer will be described below. In the organic electroluminescent device of the present embodiment, the hole injection layer is preferably formed by a wet film forming method using the composition for an organic electroluminescent device.

<Hole transporting compound>
The composition for forming a hole injection layer usually contains a hole transporting compound that becomes the hole injection layer 3. In the case of the wet film formation method, the composition for forming a hole injection layer usually also contains a solvent. The composition for forming a hole injection layer preferably has high hole transportability and can efficiently transport the injected holes. Therefore, it is preferable that the hole mobility is high and impurities that serve as traps are unlikely to be generated during production or use. Further, it is preferable that the stability is excellent, the ionization potential is small, and the transparency to visible light is high. In particular, when the hole injection layer 3 is in contact with the light emitting layer 5, those that do not quench the light emitted from the light emitting layer 5 or those that form an exciplex with the light emitting layer 5 and do not reduce the luminous efficiency are preferable.

As the hole transporting compound, a compound having an ionization potential of 4.5 eV to 6.0 eV is preferable from the viewpoint of a charge injection barrier from the anode 2 to the hole injection layer 3. Examples of hole-transporting compounds include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, compounds in which a tertiary amine is linked with a fluorene group, and hydrazone. Examples thereof include system compounds, silazane compounds, and quinacridone compounds.

Among the above-mentioned exemplified compounds, aromatic amine compounds are preferable, and aromatic tertiary amine compounds are particularly preferable, from the viewpoint of amorphousness and visible light transmission. The aromatic tertiary amine compound is a compound having an aromatic tertiary amine structure, and also includes a compound having a group derived from an aromatic tertiary amine.

The type of the aromatic tertiary amine compound is not particularly limited, but a polymer compound having a weight average molecular weight of 1000 or more and 1000,000 or less (polymerized compound in which repeating units are continuous) is easy to obtain uniform light emission due to the surface smoothing effect. ) Is preferably used.

Since the hole injecting layer 3 can improve the conductivity of the hole injecting layer by oxidizing the hole transporting compound, the hole injecting layer 3 contains the above-mentioned electron-accepting compound and the above-mentioned cationic radical compound. Is preferable.

Cationic radical compounds derived from polymer compounds such as PEDOT / PSS (Adv. Mater., 2000, Vol. 12, p. 481) and emeraldine hydrochloride (J. Phys. Chem., 1990, Vol. 94, p. 7716) It is also produced by oxidative polymerization (dehydrogenation polymerization).

The oxidative polymerization referred to here is to chemically or electrochemically oxidize a monomer in an acidic solution using peroxodisulfate or the like. In the case of this oxidative polymerization (dehydropolymerization), a cation radical obtained by removing one electron from a repeating unit of a polymer, which is polymerized by oxidizing a monomer and has an anion derived from an acidic solution as a counter anion, is generated. Generate.

<Formation of hole injection layer by wet film formation method>
When the hole injection layer 3 is formed by the wet film formation method, the material to be the hole injection layer 3 is usually mixed with a soluble solvent (solvent for the hole injection layer) to form a composition for film formation (positive). A composition for forming a hole injection layer) is prepared, and this composition for forming a hole injection layer is applied onto a layer corresponding to the lower layer of the hole injection layer 3 (usually, an anode 2) to form a film, and then dried. It is formed by letting it.

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, but it is preferably low in terms of film thickness uniformity, and hole injection Higher is preferable in that defects are less likely to occur in the layer. Specifically, it is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, particularly preferably 0.5% by weight or more, and 70% by weight or less. Is more preferable, and it is more preferably 60% by weight or less, and particularly preferably 50% by weight or less.

Examples of the solvent include ether solvents, ester solvents, aromatic hydrocarbon solvents, amide solvents and the like.

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

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. Be done.

Examples of the amide-based solvent include N, N-dimethylformamide, N, N-dimethylacetamide and the like.
In addition to these, dimethyl sulfoxide and the like can also be used.

The formation of the hole injection layer 3 by the wet film formation method is usually performed on the layer corresponding to the lower layer of the hole injection layer 3 (usually, the anode 2) after preparing the composition for forming the hole injection layer. It is carried out by applying a film to the film and drying it.
In the hole injection layer 3, the coating film is usually dried by heating, vacuum drying, or the like after the film formation.

<Formation of hole injection layer by vacuum deposition method>
When the hole injection layer 3 is formed by the vacuum deposition method, usually one or more of the constituent materials of the hole injection layer 3 (the above-mentioned hole transporting compound, electron accepting compound, etc.) are vacuumed. Place in a crucible installed inside the container (when using two or more materials, usually put each in a separate crucible), ^{exhaust the inside of the vacuum container to about 10-4} Pa with a vacuum pump, and then heat the crucible. (When two or more types of materials are used, each crucible is usually heated), and the material in the crucible is evaporated while controlling the amount of evaporation (when two or more types of materials are used, each is usually independent). Evaporates while controlling the amount of evaporation) to form the hole injection layer 3 on the anode 2 on the substrate 1 placed facing the crucible. When two or more kinds of materials are used, a mixture thereof can be placed in a crucible and heated and evaporated to form a hole injection layer.

The degree of vacuum during vapor deposition is not limited as long as the effect of the present invention is not significantly impaired, but is usually 0.1 × 10 ^-6 Torr (0.13 × 10 ^-4 Pa) or more, 9.0 × 10 ^-6 Torr ( It is 12.0 × 10 ^-4 Pa) or less. The vapor deposition rate is not limited as long as the effect of the present invention is not significantly impaired, but is usually 0.1 Å / sec or more and 5.0 Å / sec 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, but is preferably 10 ° C. or higher and 50 ° C. or lower.
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 has a function of transporting holes from the anode 2 side to the light emitting layer 5. The hole transport layer 4 of the present embodiment preferably contains the polymer of the present embodiment as the partial structure A-containing material. The hole transport layer 4 is usually formed between the anode 2 and the light emitting layer 5. When there is the hole injection layer 3 described above, the hole transport layer 4 is formed between the hole injection layer 3 and the light emitting layer 5.

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

The hole transport layer 4 may be formed by either a vacuum vapor deposition method or a wet film deposition method. In terms of excellent film forming property, it is preferably formed by a wet film forming method.

The general method for forming the hole transport layer will be described below. The hole transport layer of the present embodiment is preferably formed by a wet film forming method using the above-mentioned hole transport layer forming composition.

The hole transport layer 4 usually contains a hole transport compound. As the hole-transporting compound contained in the hole-transporting layer 4, the polymer of the present embodiment or, when the polymer has a crosslinkable group, a polymer in which the polymer is crosslinked is preferable. Further, in addition to the above polymer, two or more 3 represented by the hole transporting compound, preferably 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl. Aromatic diamine containing a secondary amine in which two or more fused aromatic rings are replaced with nitrogen atoms (Japanese Patent Laid-Open No. 5-234681), 4,4', 4''-tris (1-naphthylphenylamino) triphenyl Aromatic amine compounds having a starburst structure such as amines (J. Lumin., 72-74, pp. 985, 1997), aromatic amine compounds consisting of triphenylamine tetramers (Chem. Commun., 2175). P. 1996), Spiro compounds such as 2,2', 7,7'-tetrax- (diphenylamino) -9,9'-spirobifluorene (Synth. Metals, Vol. 91, p. 209, 1997), It may contain a carbazole derivative such as 4,4'-N, N'-dicarbazolebiphenyl and the like. Further, it contains polyvinylcarbazole, polyvinyltriphenylamine (Japanese Patent Laid-Open No. 7-53953), polyarylene ether sulfone containing tetraphenylbenzidine (Polym. Adv. Tech., Vol. 7, p. 33, 1996) and the like. But it may be.

<Formation of hole transport layer by wet film formation method>
When the hole transport layer 4 is formed by the wet film forming method, usually, in the same manner as when the hole injection layer 3 is formed by the wet film forming method, instead of the hole injection layer forming composition. It is formed using a composition for forming a hole transport layer.

When the hole transport layer 4 is formed by the wet film formation method, the hole transport layer forming composition usually further contains a solvent. As the solvent used in the hole transport layer forming composition, the same solvent as the solvent used in the hole injection layer forming composition described above can be used.
The concentration of the hole-transporting compound in the composition for forming a hole-transporting layer can be in the same range as the concentration of the hole-transporting compound in the composition for forming a hole-injecting layer.
The hole transport layer 4 can be formed by the wet film formation method in the same manner as the hole injection layer 3 film formation method described above.

<Formation of hole transport layer by vacuum deposition method>
Even when the hole transport layer 4 is formed by the vacuum vapor deposition method, it is usually positive instead of the constituent material of the hole injection layer 3 in the same manner as when the hole injection layer 3 is formed by the vacuum vapor deposition method. It can be formed by using the constituent material of the hole transport layer 4. The film formation conditions such as the degree of vacuum, the vapor deposition rate, and the temperature at the time of vapor deposition can be the same as those at the time of vacuum deposition of the hole injection layer 3.

[Light emitting layer]
The light emitting layer 5 is a layer having a function of emitting light by being excited by recombination of holes injected from the anode 2 and electrons injected from the cathode 9 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 9. The light emitting layer 5 is formed between the hole transport layer 4 and the cathode 9.

The film thickness of the light emitting layer 5 is arbitrary as long as the effect of the present invention is not significantly impaired, but a thicker one is preferable in that defects are less likely to occur in the film. On the other hand, a thinner one is preferable because it is easy to obtain a low drive voltage. Therefore, the film thickness of the light emitting layer 5 is preferably 3 nm or more, more preferably 5 nm or more, usually 200 nm or less, and further preferably 100 nm or less.

The light emitting layer 5 contains at least a material having a light emitting property (light emitting material) and preferably a material having a charge transporting property (charge transporting material). The light emitting layer of the present embodiment contains at least a light emitting material and a small molecule compound of the present embodiment as a partial structure A-containing material.

The general light emitting material and the method of forming the light emitting layer will be described below. In the organic electroluminescent device of the present embodiment, the light emitting layer is preferably formed by a wet film forming method using the above-mentioned composition for forming a light emitting layer.

<Luminescent material>
The light emitting material is not particularly limited as long as it emits light at a desired light emitting wavelength and the effect of the present invention is not impaired, and a known light emitting material can be applied. The light emitting material may be either a fluorescent light emitting material or a phosphorescent light emitting material, but a material having good luminous efficiency is preferable, and a phosphorescent light emitting material is preferable from the viewpoint of internal quantum efficiency.

Examples of the fluorescent light emitting material include the following materials.

Examples of the fluorescent light emitting material (blue fluorescent light emitting material) that gives blue light emission include naphthalene, perylene, pyrene, anthracene, coumarin, chrysene, p-bis (2-phenylethenyl) benzene, and derivatives thereof.

The fluorescent light-emitting material giving green luminescence (green fluorescent material), for example, quinacridone derivatives, coumarin _{_{derivatives, Al (C 9 H 6 NO}} ) aluminum complex such as _3.

Examples of the fluorescent light emitting material (yellow fluorescent light emitting material) that gives yellow light emission include rubrene, a perimidone derivative, and the like.

Examples of the fluorescent light emitting material (red fluorescent light emitting material) that gives red light emission include DCM (4- (dimethyanomethylene) -2-methyl-6- (p-dimethylaminostylyl) -4H-pyran) compounds, benzopyran derivatives, and rhodamine derivatives. , Benzothioxanthene derivatives, azabenzothioxanthene and the like.

Examples of the phosphorescent material include an organometallic complex containing a metal selected from Groups 7 to 11 of the long periodic table. Preferred metals selected from Groups 7 to 11 of the periodic table include ruthenium, rhodium, palladium, silver, renium, osmium, iridium, platinum, gold and the like.

As the ligand of the organic metal complex, a ligand in which a (hetero) aryl group such as a (hetero) arylpyridine ligand or a (hetero) arylpyrazole ligand is linked to a pyridine, pyrazole, phenanthroline or the like is preferable. In particular, a phenylpyridine ligand and a phenylpyrazole ligand are preferable. Here, the (hetero) aryl represents an aryl group or a heteroaryl group.

Specific preferred phosphorescent materials include tris (2-phenylpyridine) iridium, tris (2-phenylpyridine) ruthenium, tris (2-phenylpyridine) palladium, bis (2-phenylpyridine) platinum, and tris (2). Examples thereof include phenylpyridine complexes such as -phenylpyridine) osmium and tris (2-phenylpyridine) renium, and porphyrin complexes such as octaethyl platinum porphyrin, octaphenyl platinum porphyrin, octaethyl palladium porphyrin, and octaphenyl palladium porphyrin.

Polymer-based luminescent materials include poly (9,9-dioctylfluorene-2,7-diyl) and poly [(9,9-dioctylfluorene-2,7-diyl) -co- (4,4'-). (N- (4-sec-butylphenyl)) diphenylamine)], poly [(9,9-dioctylfluorene-2,7-diyl) -co- (1,4-benzo-2 {2,1'-3) } -Triazole)] and other polyfluorene-based materials, and poly [2-methoxy-5- (2-hepylhexyloxy) -1,4-phenylene vinylene] and other polyphenylene vinylene-based materials can be mentioned.

<Charge transport material>
The charge transporting material is a material having a positive charge (hole) or negative charge (electron) transport property. The charge transporting material is not particularly limited as long as the effects of the present invention are not impaired, and known charge transporting materials can be applied.

As the charge transporting material, a compound or the like conventionally used for the light emitting layer of the organic electroluminescent device can be used, and a compound used as a host material for the light emitting layer is particularly preferable.

Specific examples of the charge transporting material other than the low molecular weight compound of the present embodiment include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, and polythiophene compounds containing the polymer of the present embodiment. As a hole transporting compound in the hole injection layer such as a compound, a benzylphenyl compound, a compound in which a tertiary amine is linked with a fluorene group, a hydrazone compound, a silazane compound, a silanamine compound, a phosphamine compound, a quinacridone compound, etc. Examples thereof include the exemplified compounds. In addition, electron-transporting compounds such as anthracene-based compounds, pyrene-based compounds, carbazole-based compounds, pyridine-based compounds, phenanthroline-based compounds, oxadiazole-based compounds, and silol-based compounds can be mentioned.

Further, for example, two or more fused aromatic rings containing two or more tertiary amines represented by 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl are used as nitrogen atoms. Aromatic amine compounds having a starburst structure, such as substituted aromatic diamines (Japanese Patent Laid-Open No. 5-234681), 4,4', 4''-tris (1-naphthylphenylamino) triphenylamine, etc. Lumin., 72-74, 985, 1997), aromatic amine compounds consisting of triphenylamine tetramers (Chem. Commun., 2175, 1996), 2, 2', 7, 7 Fluorene compounds such as'-tetrax- (diphenylamino) -9,9'-spirobifluorene (Synth. Metals, Vol. 91, p. 209, 1997), 4,4'-N, N'-dicarbazolebiphenyl The compounds exemplified as the hole-transporting compounds in the hole-transporting layer such as carbazole-based compounds such as the above can also be preferably used.

In addition, 2- (4-biphenanthroline) -5- (p-talshalbutylphenyl) -1,3,4-oxadiazole (tBu-PBD), 2,5-bis (1-naphthyl)- Oxadiazole compounds such as 1,3,4-oxadiazole (BND), 2,5-bis (6'-(2', 2''-bipyridyl))-1,1-dimethyl-3,4 Examples thereof include silol compounds such as -diphenylcyrol (PyPySPyPy) and phenanthroline compounds such as vasophenanthroline (BPhen) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP, bathocuproine).

<Formation of light emitting layer by wet film formation method>
The light emitting layer 5 may be formed by a vacuum vapor deposition method or a wet film deposition method. The wet film forming method is preferable, and the spin coating method and the inkjet method are more preferable because of the excellent film forming property. In particular, when the hole transport layer 4 to be the lower layer of the light emitting layer 5 is formed by using the composition for forming the hole transport layer described above, laminating by the wet film formation method is easy. It is preferable to adopt it. When the light emitting layer 5 is formed by the wet film forming method, usually, in the same manner as when the hole injection layer is formed by the wet film forming method, instead of the composition for forming the hole injection layer described above, the above-mentioned composition is used. It is formed using a composition for forming a light emitting layer.

As a method for removing the solvent after the wet film formation, heating or depressurization can be used. As the heating means used in the heating method, a clean oven and a hot plate are preferable because heat is evenly applied to the entire film.

The heating temperature in the heating step is arbitrary as long as the effect of the present invention is not significantly impaired. A high temperature is preferable in terms of shortening the drying time, and a low temperature is preferable in terms of less damage to the material. The upper limit of the heating temperature is usually 250 ° C. or lower, preferably 200 ° C. or lower, and more preferably 150 ° C. or lower. The lower limit of the heating temperature is usually 30 ° C. or higher, preferably 50 ° C. or higher, and more preferably 80 ° C. or higher. A temperature at which the heating temperature exceeds the above upper limit is higher than the heat resistance of a commonly used charge transporting material or phosphorescent material, and may be decomposed or crystallized, which is not preferable. If the heating temperature is less than the above lower limit, it takes a long time to remove the solvent, which is not preferable. The heating time in the heating step is appropriately determined by the boiling point and vapor pressure of the solvent in the composition for forming the light emitting layer, the heat resistance of the material, and the heating conditions.

<Formation of light emitting layer by vacuum deposition method>
When the light emitting layer 5 is formed by the vacuum deposition method, one or more of the constituent materials of the light emitting layer 5 (the above-mentioned light emitting material, the low molecular weight compound of the present embodiment, the charge transporting compound, etc.) are usually used. Place in a crucible installed in a vacuum vessel (when using two or more materials, usually put each in a separate crucible), ^{exhaust the inside of the vacuum vessel to about 10-4} Pa with a vacuum pump, and then remove the crucible. Heat (usually heat each crucible when using two or more materials) and evaporate while controlling the amount of evaporation of the material in the crucible (usually each when using two or more materials). Evaporate while independently controlling the amount of evaporation) to form a light emitting layer 5 on the hole transport layer 4 placed facing the crucible. When two or more kinds of materials are used, a mixture thereof can be placed in a crucible and heated and evaporated to form the light emitting layer 5.

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

[Hole blocking layer]
A hole blocking layer 6 may be provided between the light emitting layer 5 and the electron injection layer 8 described later. The hole blocking layer 6 is a layer laminated on the light emitting layer 5 so as to be in contact with the interface of the light emitting layer 5 on the cathode 9 side.

The hole blocking layer 6 has a role of blocking holes moving from the anode 2 from reaching the cathode 9 and a role of efficiently transporting electrons injected from the cathode 9 toward the light emitting layer 5. Have. The physical properties required for the material constituting the hole blocking layer 6 are high electron mobility and low hole mobility, a large energy gap (difference between HOMO and LUMO), and an excited triplet level (T1). Is high.

Examples of the material of the hole blocking layer 6 satisfying such conditions include bis (2-methyl-8-quinolinolato) (phenolato) aluminum and bis (2-methyl-8-quinolinolato) (triphenylsilanorat) aluminum. Mixed ligand complexes such as, bis (2-methyl-8-quinolato) aluminum-μ-oxo-bis- (2-methyl-8-quinolilato) aluminum dinuclear metal complexes and other metal complexes, distyrylbiphenyl derivatives, etc. Styryl compounds (Japanese Patent Laid-Open No. 11-242996), 3- (4-biphenylyl) -4-phenyl-5- (4-tert-butylphenyl) -1,2,4-triazole and other triazole derivatives (specifically) Kaihei 7-417759), phenylintroline derivatives such as bathocuproine (Japanese Patent Laid-Open No. 10-79297), and the like can be mentioned. Further, a compound having at least one pyridine ring in which the 2, 4 and 6 positions are substituted as described in WO 2005/022962 is also preferable as a material for the hole blocking layer 6.

There is no limitation on the method of forming the hole blocking layer 6. Therefore, it can be formed by a wet film forming method, a thin film deposition method, or another method.
The film thickness of the hole blocking layer 6 is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 0.3 nm or more, preferably 0.5 nm or more, and usually 100 nm or less, preferably 50 nm or less.

[Electron transport layer]
The electron transport layer 7 is provided between the light emitting layer 5 and the electron injection layer 8 for the purpose of further improving the current efficiency of the device.

The electron transport layer 7 is formed of a compound capable of efficiently transporting electrons injected from the cathode 9 in the direction of the light emitting layer 5 between the electrodes to which an electric field is applied. The electron-transporting compound used in the electron-transporting layer 7 has high electron-injection efficiency from the cathode 9 or the electron-injection layer 8 and high electron mobility, and efficiently transports the injected electrons. It needs to be a compound that can.

Specific examples of the electron-transporting compound used in the electron-transporting layer include metal complexes such as an aluminum complex of 8-hydroxyquinolin (Japanese Patent Laid-Open No. 59-194393), 10-hydroxybenzo [h] quinoline. Metal Complex, Oxaziazole Derivative, Distyrylbiphenyl Derivative, Sirol Derivative, 3-Hydroxyflavon Metal Complex, 5-Hydroxyflavon Metal Complex, Benzoxazole Metal Complex, Benthiazole Metal Complex, Trisbenzimidazolylbenzene (US Patent No. 5645948) Specified specification), quinoxalin compound (Japanese Patent Laid-Open No. 6-207169), phenanthroline derivative (Japanese Patent Laid-Open No. 5-331459), 2-t-butyl-9,10-N, N'-dicyanoanthraquinone diimine, n-type. Examples thereof include hydride amorphous silicon carbide, n-type zinc sulfide, and n-type zinc selenium.

The film thickness of the electron transport layer 7 is usually 1 nm or more, preferably 5 nm or more, and usually 300 nm or less, preferably 100 nm or less.

The electron transport layer 7 is formed by laminating on the hole blocking layer 6 by a wet film deposition method or a vacuum vapor deposition method in the same manner as described above. Usually, the vacuum deposition method is used.

[Electron injection layer]
The electron injection layer 8 plays a role of efficiently injecting the electrons injected from the cathode 9 into the electron transport layer 7 or the light emitting layer 5.

In order to efficiently perform electron injection, the material forming the electron injection layer 8 is preferably a metal having a low work function. As an example, alkali metals such as sodium and cesium, alkaline earth metals such as barium and calcium, and the like are used. In this case, the film thickness of the electron injection layer 8 is usually preferably 0.1 nm or more and 5 nm or less.

Materials for forming the electron injection layer 8 include organic electron transport materials typified by nitrogen-containing heterocyclic compounds such as basophenanthroline and metal complexes such as aluminum complexes of 8-hydroxyquinoline, and sodium, potassium, cesium, and the like. Dope with an alkali metal such as lithium or rubidium (described in JP-A No. 10-270171, JP-A-2002-100478, JP-A-2002-1000482, etc.) also improves electron injection and transportability and is excellent. It is preferable because it makes it possible to achieve both film quality and film quality.
In this case, the film thickness of the electron injection layer 8 is usually 5 nm or more, preferably 10 nm or more, and usually 200 nm or less, preferably 100 nm or less.

The electron injection layer 8 is formed by laminating on the light emitting layer 5 or the hole blocking layer 6 or the electron transport layer 7 on the light emitting layer 5 by a wet film forming method or a vacuum vapor deposition method.
The details in the case of the wet film forming method are the same as in the case of the light emitting layer described above.

[cathode]
The cathode 9 plays a role of injecting electrons into a layer on the light emitting layer 5 side (electron injection layer 8 or light emitting layer 5 or the like).

As the material of the cathode 9, the material used for the anode 2 can be used. In order to efficiently inject electrons, it is preferable to use a metal having a low work function, and for example, a metal such as tin, magnesium, indium, calcium, aluminum, silver or an alloy thereof is used. Specific examples include alloy electrodes having a low work function such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy.

From the viewpoint of device stability, it is preferable to laminate a metal layer having a high work function and stable with respect to the atmosphere on the cathode 9 to protect the cathode made of a metal having a low work function. Examples of the metal to be laminated include metals such as aluminum, silver, copper, nickel, chromium, gold, and platinum.
The film thickness of the cathode 9 is usually the same as that of the anode 2.

[Other layers]
The organic electroluminescent device of the present embodiment may further have another layer as long as the effect of the present invention is not significantly impaired. That is, any of the above-mentioned other layers may be provided between the anode 2 and the cathode 9.

[Other element configurations]
The organic electroluminescent device of the present embodiment has a structure opposite to that described above, that is, the cathode 9, the electron injection layer 8, the electron transport layer 7, the hole blocking layer 6, the light emitting layer 5, and the holes on the substrate 1. It is also possible to stack the transport layer 4, the hole injection layer 3, and the anode 2 in this order. It is also possible to provide the organic electroluminescent device of the present invention between two substrates having at least one highly transparent substrate.

When the organic electroluminescent device of the present embodiment is applied to an organic electroluminescent device, it may be used as a single organic electroluminescent device or may be used in a configuration in which a plurality of organic electroluminescent devices are arranged in an array. , The anode and the cathode may be arranged in an XY matrix.

[Organic EL display device]
The organic EL display device (organic electroluminescent element display device) of the present embodiment uses the above-mentioned organic electroluminescent element. The model and structure of the organic EL display device of the present embodiment are not particularly limited, and can be assembled according to a conventional method using the above-mentioned organic electroluminescent element.
For example, the organic EL display device of the present invention can be used by the method described in "Organic EL Display" (Ohmsha, published on August 20, 2004, by Shizushi Tokito, Chihaya Adachi, Hideyuki Murata). Can be formed.

[Organic EL lighting]
The organic EL illumination (organic electroluminescent element illumination) of the present embodiment uses the above-mentioned organic electroluminescent element. The type and structure of the organic EL illumination of the present embodiment are not particularly limited, and can be assembled according to a conventional method using the above-mentioned organic electroluminescent element.

Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to the following examples, and the present invention can be arbitrarily modified and implemented without departing from the gist thereof.

[Synthesis Example 1: Synthesis of Polymer Compound with Partial Structure A]
<Synthesis of raw material monomer>

3-Bromo-3'-nitro-biphenyl (14.1 g, 50.5 mmol), bis (pinacolato) diboron (17.1 g, 60.6 mmol), potassium acetate (24.8 g,) in a 1000 ml flask under a nitrogen stream. 253.0 mmol) was added and nitrogen was substituted at room temperature. Then, 200 ml of 1,4-dioxane was added, and 1,1'-bis (diphenylphosphino) ferrocene-palladium (II) dichloride-dichloromethane [PdCl ₂ (dppf) CH ₂ Cl ₂ ] (1.24 g, 1. 52 mmol) was added, and the reaction was carried out at 100 ° C. for 8.5 hours.
The reaction mixture was filtered under reduced pressure, diluted with toluene, and roughly purified with activated clay. Further, the crude product was purified by column chromatography (developing solution: hexane / ethyl acetate = 80/20) to obtain Compound 1 (16.3 g, yield 99.5%).

Then, Compound 1 (8.7 g, 26.76 mmol), 1-bromo-3-iodobenzene (7.95 g, 28.1 mmol), potassium phosphate aqueous solution (2M, 40.1 ml), toluene (80 ml), ethanol. (40 ml) was placed in a flask, and the inside of the system was sufficiently substituted with nitrogen and heated to 65 ° C.
Bis (triphenylphosphine) palladium (II) dichloride (0.094 g, 0.134 mmol) was added thereto, and the mixture was stirred at 65 ° C. for 3 hours. Water was added to the reaction solution, and extraction was performed with toluene. The organic layer was dried over anhydrous magnesium sulfate and crudely purified from activated clay. The crude product was purified by column chromatography (developing solution: hexane / methylene chloride = 80/20) to obtain Compound 2 (8.6 g, yield 90.5%).

Under a nitrogen stream, 100 ml of dimethylsulfonate, compound 2 (8.55 g, 24.14 mmol), bis (pinacolato) diboron (7.36 g, 28.97 mmol), potassium acetate (7.1 g, 72.97 mmol) in a 300 ml flask. 42 mmol) was added, and the mixture was stirred at 60 ° C. for 30 minutes. Then, 1,1'-bis (diphenylphosphino) ferrocene-palladium (II) dichloride-dichloromethane [PdCl ₂ (dppf) CH ₂ Cl ₂ ] (0.99 g, 1.21 mmol) was added, and the temperature was 85 ° C. Reacted for 0 hours.
The reaction mixture was filtered under reduced pressure, the filtrate was extracted with toluene, dried over anhydrous magnesium sulfate, and purified with activated clay. Further, the crude product was purified by column chromatography (developing solution: hexane / ethyl acetate = 90/10) to obtain Compound 3 (9.3 g, yield 96.0%).

Then, Compound 3 (9.3 g, 23.18 mmol), 1-bromo-4-iodobenzene (6.88 g, 24.33 mmol), aqueous potassium phosphate solution (2M, 34.8 ml), toluene (80 ml), ethanol. (40 ml) was placed in a flask, and the inside of the system was sufficiently substituted with nitrogen and heated to 65 ° C.
Bis (triphenylphosphine) palladium (II) dichloride (0.081 g, 0.116 mmol) was added thereto, and the mixture was stirred at 65 ° C. for 3.5 hours. Water was added to the reaction solution, and extraction was performed with toluene. The organic layer was dried over anhydrous magnesium sulfate and crudely purified from activated clay. The crude product was purified by column chromatography (developing solution: hexane / methylene chloride = 75/25) to obtain Compound 4 (8.7 g, yield 87.2%).

Under a nitrogen stream, 100 ml of dimethylsulfonate, compound 4 (8.7 g, 20.22 mmol), bis (pinacolato) diboron (6.2 g, 24.26 mmol), potassium acetate (5.95 g, 60.) in a 300 ml flask. 66 mmol) was added, and the mixture was stirred at 60 ° C. for 30 minutes. Then, 1,1'-bis (diphenylphosphino) ferrocene-palladium (II) dichloride-dichloromethane [PdCl ₂ (dppf) CH ₂ Cl ₂ ] (0.83 g, 1.01 mmol) was added, and the temperature was 85 ° C. Reacted for 0 hours.
The reaction mixture was filtered under reduced pressure, the filtrate was extracted with toluene, dried over anhydrous magnesium sulfate, and purified with activated clay. Further, the crude product was purified by column chromatography (developing solution: hexane / methylene chloride = 50/50) to obtain Compound 5 (7.2 g, yield 75.0%).

Then, compound 5 (7.1 g, 14.87 mmol), commercially available 2-chloro-4,6-diphenyl-1,3,5-triazine (3.98 g, 14.87 mmol), potassium phosphate aqueous solution (2M, 23.0 ml), toluene (50 ml) and ethanol (25 ml) were placed in a flask, and the inside of the system was sufficiently replaced with nitrogen and heated to 65 ° C.
Tetrakis (triphenylphosphine) palladium (0) (0.52 g, 0.45 mmol) was added thereto, and the mixture was stirred at 85 ° C. for 4.0 hours. The precipitated insoluble material was filtered under reduced pressure, and the filtrate was washed with 50 ml of methylene chloride and added dropwise to 200 ml of ethanol. The precipitate was filtered under reduced pressure and dried to obtain Compound 6 (5.3 g, yield 61.2%).

Under a nitrogen stream, 500 ml tetrahydrofuran, 50 ml ethanol, compound 6 (5.3 g, 9.10 mmol), palladium / carbon (10%, about 55% wet product, 0.72 g) were placed in a 1000 ml flask, and 50 The mixture was stirred at ° C. for 15 minutes. Then, human lazine monohydrate (3.1 g) was added dropwise, and the reaction was carried out at this temperature for 3 hours.
The reaction mixture was filtered under reduced pressure with water-moist Celite, and the filtrate was concentrated to obtain Compound 7 (4.8 g, yield 95.1%).

In a 500 ml flask, compound 8 (8.0 g, 49 mmol), 1-bromo-1'-iodo-3,3'-biphenyl (17.7 g, 49 mmol), toluene 120 ml, ethanol 60 ml, 2M potassium phosphate aqueous solution (17.7 g, 49 mmol). 62 ml) was added and nitrogen bubbling was performed for 30 minutes. After adding tetrakis (triphenylphosphine) palladium (0) (1.43 g, 1.24 mmol), the mixture was heated and stirred at 90 ° C. for 3 hours. Then, the mixture was cooled to room temperature, water and toluene were added, and the mixture was separated and washed, and then the organic layer was dried over anhydrous magnesium sulfate. Then, the solvent was removed under reduced pressure. The obtained residue was purified by silica gel column chromatography (dichloromethane / hexane = 1/9) to obtain 15.5 g of Compound 9 as a colorless oil.

In a 500 ml flask, compound 9 (15.5 g, 44 mmol), 3-aminophenylboronic acid monohydrate (6.4 g, 41 mmol), toluene 100 ml, ethanol 50 ml, and 2 M potassium phosphate aqueous solution (55 ml) were placed. Nitrogen bubbling was performed for 30 minutes. After adding tetrakis (triphenylphosphine) palladium (0) (1.3 g, 1.15 mmol), the mixture was heated and stirred at 90 ° C. for 3.5 hours. Then, the mixture was cooled to room temperature, water and toluene were added, and the mixture was separated and washed, and then the organic layer was dried over anhydrous magnesium sulfate. Then, the solvent was removed under reduced pressure. The obtained residue was purified by silica gel column chromatography (ethyl acetate / hexane = 2/8) to obtain 7.8 g of Compound 10 as a pale yellow starch syrup.

In a 1 L flask, 270 ml of toluene, 135 ml of ethanol, 20.0 g (44.8 mmol) of compound 11, 50.72 g (179.3 mmol) of 1-bromo-4-iodotoluene, and 2 M aqueous potassium phosphate solution (191 ml). The solution containing the above was vacuum degassed and then replaced with nitrogen. It was heated under a nitrogen stream and stirred for 30 minutes. Then, 0.63 g (0.90 mmol) of bis (triphenylphosphine) palladium (II) dichloride was added, and the mixture was refluxed for 6 hours. Water was added to the reaction mixture, extracted with toluene, and treated with anhydrous magnesium sulfate and activated clay. After heating and refluxing the toluene solution, the insoluble material was filtered and recrystallized to obtain compound 12 as a colorless solid (yield 14.2 g, yield 60.2%).

Compound 14 was synthesized by the same method as that for compound 12 except that 1-bromo-4-iodobenzene was used instead of 5-bromo-2-iodotoluene.

Compound 12 (2.5 g, 4.7 mmol), Compound 13 (2.134 g, 6.1 mmol), Compound 10 (0.51 g, 1.4 mmol), Compound 7 (1.04 g, 1.9 mmol), tert- Sodium butoxy (3.48 g, 36.2 mmol) and toluene (71 ml) were charged, the inside of the system was sufficiently replaced with nitrogen, and the mixture was heated to 60 ° C. (solution A1).
Separately, in a 14 ml solution of tris (dibenzylideneacetone) dipalladium complex (86.0 mg, 0.09 mmol) in toluene, [4- (N, N-dimethylamino) phenyl] di-tert-butylphosphine (Amphos) (199). .4 mg, 0.8 mmol) was added and the mixture was heated to 60 ° C. (solution B1).

Solution B1 was added to solution A1 in a nitrogen stream, and a heating reflux reaction was carried out for 1.0 hour. After confirming that compounds 7, 10 and 13 had disappeared, compound 14 (1.78 g, 3.5 mmol) was added. After heating under reflux for 2 hours, bromobenzene (1.84 g, 11.7 mmol) was added, and the mixture was heated under reflux for 1 hour. The reaction mixture was allowed to cool and added dropwise to an ethanol / water (370 ml / 70 ml) solution to obtain an end-capped crude polymer.
The end-capped crude polymer was dissolved in toluene, reprecipitated in acetone, and the precipitated polymer was filtered off. The obtained polymer was dissolved in toluene, washed with dilute hydrochloric acid, and reprecipitated with ammonia-containing ethanol. The polymer collected by filtration was purified by column chromatography to obtain the target polymer 1 (2.5 g). The molecular weight and the like of the obtained polymer 1 were as follows.

Weight average molecular weight (Mw) = 20,600
Number average molecular weight (Mn) = 15,260
Dispersity (Mw / Mn) = 1.35

[Example 1]
An organic electroluminescent device was manufactured by the following method.
A transparent conductive film of indium tin oxide (ITO) deposited on a glass substrate to a thickness of 70 nm (manufactured by Sanyo Vacuum Co., Ltd., sputter-deposited product) is 2 mm wide using ordinary photolithography technology and hydrochloric acid etching. The stripes were patterned to form an anode. The substrate on which the ITO pattern is formed is washed in the order of ultrasonic cleaning with an aqueous surfactant solution, water washing with ultrapure water, ultrasonic cleaning with ultrapure water, and water washing with ultrapure water, and then dried with compressed air. Finally, UV ozone cleaning was performed.

As the composition for forming the hole injection layer, 100 parts by weight of the hole-transporting polymer compound having a repeating structure represented by the following formula (P-1) and the compound 20 represented by the following formula (HI-1). The parts by weight were weighed and dissolved in ethyl benzoate to prepare a composition having a solid content concentration of 3.0% by weight.

This composition for forming a hole injection layer is spin-coated on the substrate in the atmosphere and dried in the air at 240 ° C. for 30 minutes to form a uniform thin film having a film thickness of 40 nm, and hole injection is performed. Layered.

Next, 100 parts by weight of the charge-transporting polymer compound represented by the following formula (HT-1), which is the polymer 1 synthesized in Synthesis Example 1, is dissolved in cyclohexylbenzene and prepared from a 3.0% by weight solution. A composition for forming a hole transport layer was prepared.
This composition for forming a hole transport layer is spin-coated in a nitrogen glove box on a substrate coated with the hole injection layer and dried at 230 ° C. for 30 minutes on a hot plate in the nitrogen glove box to form a film. A uniform thin film having a thickness of 40 nm was formed to form a hole transport layer.

Subsequently, as the material of the light emitting layer, the compound represented by the following formula (H-1) is 15 parts by weight, the compound represented by the following formula (H-2) is 15 parts by weight, and the following formula (H-3) is used. Weigh 70 parts by weight of the compound represented by the compound and 20 parts by weight of the compound represented by the following formula (D-1), dissolve the compound in cyclohexylbenzene, and prepare a solution having a solid content concentration of 7.8% by weight for forming a light emitting layer. Prepared as a composition.

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

The substrate on which the film was formed up to the light emitting layer was installed in a vacuum vapor deposition apparatus, and the inside of the apparatus was exhausted until it became ^{2 × 10 -4 Pa or less.}

Next, the compound represented by the following formula (HB-1) and 8-hydroxyquinolinolatrithium are co-deposited on the light emitting layer at a film thickness ratio of 2: 3 by a vacuum deposition method at a rate of 1 Å / sec. Then, a hole blocking layer having a film thickness of 30 nm was formed.

Subsequently, a striped shadow mask having a width of 2 mm was brought into close contact with the substrate so as to be orthogonal to the ITO stripe of the anode as a mask for cathode vapor deposition, and installed in another vacuum vapor deposition apparatus.
Then, as the cathode, aluminum was heated by a molybdenum boat to form an aluminum layer having a film thickness of 80 nm at a vapor deposition rate of 1 to 8.6 Å / sec to form a cathode.
As described above, an organic electroluminescent device having a light emitting area portion having a size of 2 mm × 2 mm was obtained.

[Comparative Example 1]
Examples except that the material composition of the light emitting layer was changed to (H-4) :( H-5) :( H-3) :( D-1) = 15: 15: 70: 20 by weight ratio. An organic electric field light emitting device was manufactured in the same manner as in 1. (H-4) and (H-5) are represented by the following equations.

[Evaluation of element]
^{The voltage when a current of 10 mA / cm 2} is applied to the organic electroluminescent device obtained in Example 1 and Comparative Example 1 is measured, and the value obtained by subtracting the voltage of Comparative Example 1 from the voltage of Example 1 is relative. It was set to voltage. Further, the current luminous efficiency (cd / A) at that time was measured, and the relative current luminous efficiency of Example 1 when the current luminous efficiency of Comparative Example 1 was set to 1 was taken as the relative luminous efficiency.
Further, these organic electroluminescent elements are ^{driven at 40 mA / cm 2} , the 15% luminance attenuation lifetime (LT85) is measured, and the ratio when the 15% attenuation lifetime of Comparative Example 1 is set to 1 (hereinafter, “relative attenuation lifetime”). ".) Was requested.
They are shown in Table 1.

From Table 1, the organic field light emitting device of the present invention containing a compound having the same partial structure A and a structure represented by the formula (TzP) in the hole transport layer and the light emitting layer has a lower voltage and a longer life. I found out that
Here, the charge-transporting polymer compound represented by the formula (HT-1) and the compound represented by the formula (H-1) both used in Example 1 have a structure in which four benzene rings are linked to triazine. Therefore, it has a high degree of commonality, and this point is also considered to contribute to the extension of life.

[Example 2]
An organic electroluminescent device was manufactured by the following method.
A 2 mm wide stripe of indium tin oxide (ITO) transparent conductive film deposited on a glass substrate to a thickness of 50 nm (a sputtered film product manufactured by Geomatec) using ordinary photolithography technology and hydrochloric acid etching. The anode was formed by patterning. The substrate on which the ITO pattern is formed is washed in the order of ultrasonic cleaning with an aqueous surfactant solution, water washing with ultrapure water, ultrasonic cleaning with ultrapure water, and water washing with ultrapure water, and then dried with compressed air. Finally, UV ozone cleaning was performed.

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

This composition for forming a hole injection layer is spin-coated on the substrate in the atmosphere and dried on an atmospheric hot plate at 240 ° C. for 30 minutes to form a uniform thin film having a film thickness of 40 nm to form a hole injection layer. And said.

Next, as the hole transport layer material, 100 parts by weight of the charge transport polymer compound represented by the following formula (HT-2) is dissolved in cyclohexylbenzene, and the hole transport layer is composed of a 3.0% by weight solution. A composition for formation was prepared.
This composition for forming a hole transport layer is spin-coated in a nitrogen glove box on a substrate coated with the hole injection layer and dried in a hot plate in a nitrogen glove box at 230 ° C. for 30 minutes to form a film. A uniform thin film having a thickness of 40 nm was formed to form a hole transport layer.

Subsequently, as the material of the light emitting layer, 50 parts by weight of the compound represented by the formula (H-1) used in Example 1, 50 parts by weight of the compound represented by the following formula (H-6), and the above. The compound represented by the formula (D-1) was weighed in 15 parts by weight and dissolved in cyclohexylbenzene to prepare a solution having a solid content concentration of 5.0% by weight as a light emitting layer forming composition.

This composition for forming a light emitting layer is spin-coated on a substrate coated with the hole transport layer in a nitrogen glove box, dried on a hot plate in the nitrogen glove box at 120 ° C. for 20 minutes, and has a film thickness of 80 nm. A uniform thin film was formed to form a light emitting layer.

Next, the compound represented by the following formula (ET-1) and 8-hydroxyquinolinolatrithium are co-deposited on the light emitting layer at a film thickness ratio of 2: 3 by a vacuum deposition method at a rate of 1 Å / sec. Then, a hole blocking layer having a film thickness of 30 nm was formed.

[Comparative Example 2]
Organic electric field emission in the same manner as in Example 1 except that the material composition of the light emitting layer was changed to (H-4) :( H-6) :( D-1) = 50:50:15 by weight ratio. The element was manufactured. (H-4) is shown in Comparative Example 1.

[Evaluation of element]
The voltage and external quantum efficiency (EQE (%)) when the organic electroluminescent devices obtained in Example 2 and Comparative Example 2 were energized and ^{emitted with a brightness of 1000 cd / m 2 were determined.}
The value obtained by subtracting the voltage of Comparative Example 2 from the voltage of Example 2 is shown in Table 2 as a relative voltage.
The EQE of Example 2 when the EQE of Comparative Example 2 is 1, is shown in Table 2 as a relative EQE.
Further, as an evaluation of the drive life of the element, ^{the time (LT90 (hr)) in which the element is continuously energized at a current density of 60 mA / cm 2} and the brightness of the element decreases to 90% of the initial brightness is measured, and Comparative Example 2 The life of the LT90 of Example 2 when the LT90 of the above is set to 1 is shown in Table 2 as a relative life.

From Table 2, the organic field light emitting device of the present invention containing a compound having the same partial structure A and a structure represented by the formula (TzP) in the hole transport layer and the light emitting layer has a lower voltage and a longer life. I found out that

[Example 3]
As the material of the light emitting layer, 50 parts by weight of the compound represented by the following formula (H-7), 50 parts by weight of the compound represented by the following formula (H-8), and the above formula (D-1) are represented. The device was produced in the same manner as in Example 2 except that 15 parts by weight of the compound to be used was weighed and dissolved in cyclohexylbenzene to prepare a solution having a solid content concentration of 5.0% by weight as a composition for forming a light emitting layer. bottom.

[Example 4]
As the material of the light emitting layer, the compound represented by the formula (H-1) is represented by 50 parts by weight, the compound represented by the formula (H-8) is represented by 50 parts by weight, and the compound represented by the formula (D-1). The device was produced in the same manner as in Example 2 except that 15 parts by weight of the compound to be used was weighed and dissolved in cyclohexylbenzene to prepare a solution having a solid content concentration of 5.0% by weight as a composition for forming a light emitting layer. bottom.

[Comparative Example 3]
As the material of the light emitting layer, the compound represented by the formula (H-4) is represented by 50 parts by weight, the compound represented by the formula (H-8) is represented by 50 parts by weight, and the compound represented by the formula (D-1). The device was produced in the same manner as in Example 2 except that 15 parts by weight of the compound to be used was weighed and dissolved in cyclohexylbenzene to prepare a solution having a solid content concentration of 5.0% by weight as a composition for forming a light emitting layer. bottom.

[Comparative Example 4]
As the hole transport layer material, the charge transport polymer compound represented by the following formula (HT-3) is used instead of the charge transport polymer compound represented by the formula (HT-2). Made an element in the same manner as in Comparative Example 3.

[Evaluation of element]
The voltage and external quantum efficiency (EQE (%)) when the organic electroluminescent devices obtained in Examples 3 and 4 and Comparative Examples 3 and 4 were energized and ^{emitted with a brightness of 1000 cd / m 2 were determined.} ..
The values obtained by subtracting the voltage of Comparative Example 4 from the voltages of Example 3, Example 4, and Comparative Example 3 are shown in Table 3 as relative voltages.
Table 3 shows the EQEs of Example 3, Example 4, and Comparative Example 3 when the EQE of Comparative Example 4 was 1, as relative EQEs.
Further, as an evaluation of the drive life of the device, the time (LT95 (hr)) at which the brightness of the device drops to 95% of the initial brightness is measured by continuously energizing the device at a current density of ^{60 mA / cm 2, and Comparative Example 4} Table 3 shows the lifetimes of the LT95s of Example 3, Example 4, and Comparative Example 3 when the LT95 of 1 was set to 1, as relative lifetimes.

From Table 3, the organic field light emitting device of the present invention containing a compound having the same partial structure A and a structure represented by the formula (TzP) in the hole transport layer and the light emitting layer has a lower voltage and a longer life. I found out that

[Example 5]
As the material of the light emitting layer, 50 parts by weight of the compound represented by the following formula (H-9), 50 parts by weight of the compound represented by the above formula (H-6), and the following formula (D-2) are represented. The device was prepared in the same manner as in Example 3 except that 15 parts by weight of the compound to be used was weighed and dissolved in cyclohexylbenzene to prepare a solution having a solid content concentration of 5.0% by weight as a composition for forming a light emitting layer. bottom.

[Comparative Example 5]
As the hole transport layer material, the charge transport polymer compound represented by the formula (HT-3) was used instead of the charge transport polymer compound represented by the formula (HT-2), and the charge transport polymer compound represented by the formula (HT-3) was used. As the material of the light emitting layer, 50 parts by weight of the compound represented by the formula (H-9), 50 parts by weight of the compound represented by the formula (H-6), and the following formula (D-3). 15 parts by weight of the compound to be used was weighed and dissolved in cyclohexylbenzene to prepare a solution having a solid content concentration of 5.0% by weight as a composition for forming a light emitting layer. bottom.

[Evaluation of element]
The voltage and external quantum efficiency (EQE (%)) when the organic electroluminescent devices obtained in Example 5 and Comparative Example 5 were energized and ^{emitted with a brightness of 1000 cd / m 2 were determined.}
The value obtained by subtracting the voltage of Comparative Example 5 from the voltage of Example 5 is shown in Table 4 as a relative voltage.
The EQE of Example 5 when the EQE of Comparative Example 5 is set to 1 is shown in Table 4 as a relative EQE.
Further, as an evaluation of the drive life of the element, ^{the time (LT95 (hr)) in which the element is continuously energized at a current density of 60 mA / cm 2} and the brightness of the element decreases to 95% of the initial brightness is measured, and Comparative Example 5 The life of the LT95 of Example 5 when the LT95 of the above is set to 1 is shown in Table 4 as a relative life.

From Table 4, the organic field light emitting device of the present invention containing a compound having the same partial structure A and a structure represented by the formula (TzP) in the hole transport layer and the light emitting layer has a lower voltage and a longer life. I found out that

[Example 6]
As the hole transport layer material, the charge transport polymer compound represented by the following formula (HT-4) was used instead of the charge transport polymer compound represented by the formula (HT-2). As the material of the light emitting layer, 50 parts by weight of the compound represented by the following formula (H-10), 25 parts by weight of the compound represented by the following formula (H-11), and the following formula (H-12). 25 parts by weight of the compound to be used and 30 parts by weight of the compound represented by the following formula (D-4) are weighed and dissolved in cyclohexylbenzene to prepare a solution having a solid content concentration of 5.0% by weight for forming a light emitting layer. The element was produced in the same manner as in Example 2 except that it was prepared as a product.

[Comparative Example 6]
As the hole transport layer material, the charge transport polymer compound represented by the formula (HT-3) was used instead of the charge transport polymer compound represented by (HT-4). The element was manufactured in the same manner as in Example 6.

[Evaluation of element]
The external quantum efficiency (EQE (%)) when the organic electroluminescent devices obtained in Example 6 and Comparative Example 6 were energized and ^{emitted with a brightness of 1000 cd / m 2 was determined.} The EQE of Example 6 when the EQE of Comparative Example 6 is set to 1 is shown in Table 5 as a relative EQE.
Further, as an evaluation of the drive life of the element, the time (LT90 (hr)) at which the brightness of the element decreases to 90% of the initial brightness is measured by continuously energizing the element at a current density of ^{15 mA / cm 2, and Comparative Example 6} The life of the LT90 of Example 6 when the LT90 of the above is set to 1 is shown in Table 5 as a relative life.

From Table 5, it was found that the organic electroluminescent device of the present invention containing a compound having the same partial structure A in the hole transport layer and the light emitting layer has a lower voltage and a longer life.

Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the intent and scope of the invention.
This application is based on Japanese Patent Application No. 2020-0272324 filed on February 20, 2020, which is incorporated by reference in its entirety.

1 Substrate 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Light emitting layer 6 Hole blocking layer 7 Electron transport layer 8 Electron injection layer 9 Cathode 10 Organic electric field light emitting device

Claims

An organic electroluminescent device having an anode, a cathode, and an organic layer between the anode and the cathode on a substrate.
The organic layer has a hole transport layer and a light emitting layer adjacent to the hole transport layer.
An organic electric field light emitting device in which at least one of the materials contained in the hole transport layer and at least one of the materials contained in the light emitting layer both have the same partial structure A represented by the following formula (31).

(In equation (31)
Ring HA represents an aromatic heterocycle of a monocyclic ring or a 2-6 condensed ring which may have a substituent.
The benzene ring in formula (31) may have a substituent.
Ar 0 is an aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or an aromatic hydrocarbon group which may have a substituent and Represents a monovalent group in which a plurality of two or more groups selected from aromatic heterocyclic groups which may have a substituent are linked.
n1 represents an integer less than or equal to the number in which Ar 0 can be replaced with 0 or ring HA.
When n1 is 2 or more, a plurality of Ar 0s may be the same or different. )
The organic electric field light emitting device according to claim 1, wherein at least one of the material having the partial structure A contained in the hole transport layer and the material having the partial structure A contained in the light emitting layer has two or more partial structures A. ..
The organic electric field light emitting device according to claim 1 or 2, wherein the partial structure A represented by the formula (31) is a structure represented by any of the following formulas (33) to (35).

(In formula (33) to formula (35),
Ar 0 and n1 are synonymous with those in the equation (31). The benzene ring in the formulas (33) to (35) may have a substituent.
X and Y each independently represent a C atom or an N atom.
When X and Y are C atoms, Ar 0 may be bonded. )
The organic electroluminescent device according to claim 3, wherein X and Y are N atoms in the partial structure represented by the above formula (35).
The organic field light emitting device according to any one of claims 1 to 4, wherein the material having the partial structure A contained in the hole transport layer is a polymer compound having a repeating unit represented by the following formula (1). ..

(In equation (1),
A represents a partial structure A.
G represents an aromatic hydrocarbon group that may have a substituent, or an N atom.
Ar 2 may have a divalent aromatic hydrocarbon group which may have a substituent, a divalent aromatic heterocyclic group which may have a substituent, or a substituent. A divalent group in which a plurality of two or more groups selected from a good divalent aromatic hydrocarbon group and a divalent aromatic heterocyclic group which may have a substituent are directly or via a linking group are linked. Represents.
Ar 20 is directly bonded, has a divalent aromatic hydrocarbon group which may have a substituent, or a plurality of divalent aromatic hydrocarbon groups which may have a substituent are linked. Represents a divalent group. )
Claimed that G is a group consisting of any of a benzene ring which may have a substituent, a fluorene ring which may have a substituent, and a spirofluorene ring which may have a substituent. Item 5. The organic electric field light emitting element according to Item 5.
The organic electroluminescent device according to claim 5, wherein G is an N atom.
The organic electric field light emitting device according to claim 7, wherein the repeating unit represented by the formula (1) is a repeating unit represented by any of the following formulas (2) -1 to (2) -3.

(In equation (2) -1 to equation (2) -3,
A is synonymous with A in the above formula (1).
Q represents -C (R 5 ) (R 6 )-, -N (R 7 )-or -C (R 11 ) (R 12 ) -C (R 13 ) (R 14 )-.
R 1 to R 4 each independently represent an alkyl group which may have a substituent, an alkoxy group which may have a substituent, or an aralkyl group which may have a substituent.
R 5 to R 7 and R 11 to R 14 may independently have an alkyl group which may have a substituent, an alkoxy group which may have a substituent, and a substituent. Represents an aromatic hydrocarbon group which may have an aralkyl group or a substituent.
a and b are independently integers of 0 to 4.
c1 to c5 are independently integers of 0 to 3.
However, at least one of c3 and c5 is 1 or more.
d1 to d4 are independently integers of 1 to 4.
When there are a plurality of R 1 , R 2 , R 3 , and R 4 in the repeating unit, R 1 , R 2 , R 3 , and R 4 may be the same or different. )
The organic electroluminescent device according to any one of claims 5 to 8, wherein -Ar 20- A in the formula (1) is represented by the following formula (15).

(In equation (15),
X and Y each independently represent a C atom or an N atom. The ring having X, Y and N corresponds to the ring HA in the formula (31).
Ar 1 is a divalent aromatic hydrocarbon group which may have a substituent or a divalent aromatic hydrocarbon group in which two or more divalent aromatic hydrocarbon groups which may have a substituent are linked. Represents a group.
Ar 3 and Ar 4 may independently have an aromatic hydrocarbon group which may have a substituent, an aromatic heterocyclic group which may have a substituent, or a substituent. Represents a monovalent group in which a plurality of two or more groups selected from a good aromatic hydrocarbon group and an aromatic heterocyclic group which may have a substituent are linked.
However, in at least one of Ar 1 , Ar 3 , and Ar 4 , the structure bonded to the ring HA is a benzene ring.
* Represents the binding site with G. )
The organic electroluminescent device according to claim 9, wherein -Ar 20- A in the formula (1) is represented by the following formula (16).

(In equation (16),
X, Y, and * are synonymous with those in the above equation (15).
The ring having X, Y and N corresponds to ring HA as in the formula (15).
Ar 1 'is the direct bond or the formula (15) represents the residue of a case structure of bonding to the ring of HA Ar 1 is a benzene ring.
Ar 3 ', Ar 4', in the hydrogen atom or each said formula (15) represents the residue of a case structure that binds to Ar 3, Ar 4 rings HA is a benzene ring. )
The organic electric field light emitting device according to any one of claims 5 to 10, wherein the material having the partial structure A contained in the hole transport layer further has a repeating unit represented by the following formula (3).

(In equation (3),
Ar 13 represents an aromatic hydrocarbon group which does not contain a partial structure A and may have a substituent or an aromatic heterocyclic group which may have a substituent.
Ar 14 may have a divalent aromatic hydrocarbon group which may have a substituent, a divalent aromatic heterocyclic group which may have a substituent, or a substituent. A divalent group in which a plurality of two or more groups selected from a good divalent aromatic hydrocarbon group and a divalent aromatic heterocyclic group which may have a substituent are directly or via a linking group are linked. Represents. )
Claimed that the light emitting layer contains a small molecule compound having the partial structure A, and the small molecule compound is a compound having a molecular weight of 5,000 or less represented by any of the following formulas (10) to (12). Item 2. The organic electric field light emitting element according to Items 1 to 11.

(In equations (10) to (12),
A is the partial structure A.
B represents a single bond or any substructure.
na, nb and nc represent integers from 1 to 5.
When na, nb, and nc are 2 or more, the plurality of A, B, and AB may be the same or different. )
The organic electroluminescent device according to claim 12, wherein the small molecule compound represented by the formula (10) is represented by the following formula (10A).

(In formula (10A),
HA represents any of the trivalent aromatic heterocyclic groups represented by the following structural formulas (10A-a), (10A-b) and (10A-c).
Xa 1 , Ya 1 , and Za 1 each independently have a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms, which may have a substituent, or a carbon which may have a substituent. Represents a divalent aromatic heterocyclic group of numbers 3 to 30.
Each of Xa 2 , Ya 2 and Za 2 independently has a hydrogen atom, an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or a carbon number which may have a substituent. Represents 3 to 30 aromatic heterocyclic groups.
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.
When g11, h11, and j11 are 2 or more, Xa 1 , Ya 1 , and Za 1 may be the same or different.
R 31 represents a hydrogen atom or a substituent. The four R 31s may be the same or different. )

(In formulas (10A-a) to (10A-c), * represents the bonding position.)
The organic electroluminescent device according to claim 13, wherein the small molecule compound represented by the formula (10) is represented by the following formulas (10A-1) to (10A-3).

(In formulas (10A-1) to (10A-3),
Xa 1 , Ya 1 , Za 1 , Xa 2 , Ya 2 , and Za 2 are synonymous with those in equation (10).
R 33 represents a hydrogen atom or a substituent. The plurality of R 33s may be the same or different.
g11', h11' and j11'independently represent integers from 0 to 5.
When g11', h11', and j11' are 2 or more, the plurality of Xa 1 , Ya 1 , and Za 1 may be the same or different. )
The organic electroluminescent device according to claim 12, wherein the small molecule compound represented by the formula (10) is represented by the following formula (10B).

(In formula (10B),
A has the same meaning as in the above formula (10).
Xb 1 , Yb 1 , and Zb 1 each independently may have a substituent or a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms, or a carbon which may have a substituent. Represents a divalent aromatic heterocyclic group of numbers 3 to 30.
p12, q12, and r12 each independently represent an integer of 0 to 6.
When p12, q12, and r12 are 2 or more, the plurality of Xb 1 , Yb 1 , and Zb 1 may be the same or different.
q13 and r13 independently represent 0 or 1, respectively.
However, q12 and q13 are not 0 at the same time, and r12 and r13 are not 0 at the same time.
Yb 2 when q13 is 0 and Zb 2 when r13 is 0 independently have a hydrogen atom, an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or a substituent. Represents an aromatic heterocyclic group having 3 to 30 carbon atoms which may have.
When q13 is 1, Yb 2 is a direct bond.
When r13 is 1, Zb 2 is a direct bond. )
The organic electroluminescent device according to claim 15, wherein the small molecule compound represented by the formula (10) is represented by the following formula (10B-1).

(In equation (10B-1),
A, Xb 1 , Yb 1 , Zb 1 , Yb 2 , Zb 2 , q13, and r13 are synonymous with those in the above formula (10B).
p12', q12' and r12'independently represent integers from 0 to 5.
When p12', q12', and r12'are 2 or more, a plurality of Xb 1 , Yb 1 , and Zb 1 may be the same or different.
q15 and r15 are 4 or 5 independently, respectively.
R 33 is a hydrogen atom or a substituent.
The plurality of R 33s in the formula (10B-1) may be the same or different. )
The organic electroluminescent device according to claim 12, wherein the small molecule compound represented by the formula (12) is represented by the following formula (12A).

(In formula (12A),
Rings HA and Ar 0 are synonymous with those in the above formula (31).
nc has the same meaning as in the above formula (12).
Each of Xc 1 and Yc 1 independently has a divalent aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or 3 to 30 carbon atoms which may have a substituent. Represents a divalent aromatic heterocyclic group of.
Each of Xc 2 and Yc 2 has a hydrogen atom, an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or an aromatic hydrocarbon group having 3 to 30 carbon atoms which may have a substituent. Represents an aromatic heterocyclic group.
Each of s11 and t11 independently represents an integer of 0 to 6.
When s11 and t11 are 2 or more, the plurality of Xc 1 and Yc 1 may be the same or different.
R 31 represents a hydrogen atom or a substituent.
u11 is the number of substitutable substituents R 31.
u12 is a number in which the substituent Ar 0 can be substituted.
If u11 is 2 or more, plural R 31 may be different even in the same. )
An organic EL display device including the organic electroluminescent device according to any one of claims 1 to 17.
Organic EL lighting including the organic electroluminescent element according to any one of claims 1 to 17.