JP2020152746A - Composition for organic electroluminescent element, organic electroluminescent element, display device, and lighting device - Google Patents

Abstract

To enable production of an organic electroluminescent element by wet deposition and provide an organic electroluminescent element with a lower driving voltage and a longer driving life than the prior art.SOLUTION: A composition for an organic electroluminescent element comprises a compound represented by the specified formula (1), a compound represented by the specified formula (2) which has a maximum emission wavelength longer than the compound represented by the formula (1), and a solvent.SELECTED DRAWING: None

Description

The present invention relates to a composition for an organic electroluminescent device that is useful for forming a light emitting layer of an organic electroluminescent device (hereinafter, may be referred to as an "organic EL device"). The present invention also relates to an organic electroluminescent device having a light emitting layer formed by using the composition for an organic electroluminescent device, a display device having the organic electroluminescent device, and a lighting device.

Various electronic devices that use organic EL elements, such as organic EL lighting and organic EL displays, have been put into practical use. Since the applied voltage of the organic electroluminescent element is low, the power consumption is low and it is possible to emit three primary colors. Therefore, it has begun to be applied not only to large display monitors but also to small and medium-sized displays such as mobile phones and smartphones. ..
An organic electroluminescent device is manufactured by stacking a plurality of layers such as a light emitting layer, a charge injection layer, and a charge transport layer. Currently, most organic electroluminescent devices are manufactured by depositing an organic material under vacuum, but the vacuum vapor deposition method complicates the vapor deposition process and is inferior in productivity. It is extremely difficult to increase the size of lighting and display panels with organic electroluminescent devices manufactured by the vacuum deposition method.

In recent years, a wet film forming method (coating method) has been studied as a process for efficiently manufacturing an organic electroluminescent element that can be used for a large-scale display or lighting. The wet film deposition method has an advantage that a stable layer can be easily formed as compared with the vacuum film deposition method, and is therefore expected to be mass-produced for displays and lighting devices and applied to large-scale devices.
In order to manufacture an organic electroluminescent device by a wet film formation method, all the materials used must be soluble in an organic solvent and can be used as ink. If the material used is inferior in solubility,
Since operations such as heating for a long time are required, the material may deteriorate before use.
Further, if the uniform state cannot be maintained for a long time in the solution state, the material is precipitated from the solution, and the film formation by an inkjet device or the like becomes impossible. The material used in the wet film formation method dissolves quickly in an organic solvent and maintains a uniform state without precipitation after dissolution.
Solubility in the two senses is required.

The advantage of the wet film deposition method over the vacuum film deposition method is that more material types can be used in one layer. In the vacuum deposition method, it becomes difficult to control the vapor deposition rate to be constant as the number of material types increases, whereas in the wet film deposition method, even if the material types increase, as long as each material is dissolved in the organic solvent Inks with a constant component ratio can be produced.
In recent years, attempts have been made to improve the performance of organic electroluminescent devices by using two or more types of iridium complexes in ink to increase the luminous efficiency of the organic electroluminescent device or lower the drive voltage by taking advantage of this advantage. (For example, Patent Documents 1 and 2).

On the other hand, focusing on the chemical structure of the material, an attempt has been made to use an iridium complex containing a carbazole ring via an arylene group as a ligand as a light emitting material (for example, Patent Document 3).
).

International Publication No. 2015/192939 International Publication No. 2016/125560 International Publication No. 2003/084973

However, the above-mentioned prior art is not sufficient in terms of the performance of the organic electroluminescent device for lighting and display applications.
The present invention provides an organic electroluminescent device which can produce an organic electroluminescent device by a wet film forming method, has a lower driving voltage than the conventional one, and has a long driving life.

As a result of diligent studies in view of the above problems in order to take advantage of the wet film formation method in which more material types can be used in one layer, the present inventor has obtained a carbazole ring having a hole transport property as a ligand. The iridium complex contained in is used as a hole transporting assist dopant instead of a light emitting material, and an iridium complex having a longer maximum emission wavelength than the hole transporting assist dopant is used as a light emitting material. We have found that the performance of an organic electroluminescent element is improved by preparing an organic electroluminescent element in which a material is dissolved in a solvent and using the composition to prepare an organic electroluminescent element, and completed the present invention. It was.

Since the composition for an organic electroluminescent device of the present invention contains an iridium complex containing a carbazole ring as a ligand as a hole transporting assist dopant, it is possible to produce an organic electroluminescent device having a lower driving voltage than before. is there. Further, in the composition for an organic electroluminescent device of the present invention, since the recombination region in the light emitting layer expands to the side far from the anode due to the presence of the hole transporting assist dopant, the load associated with recombination and light emission Since the bias is reduced, it is possible to manufacture an organic electroluminescent device having a longer drive life than the conventional one.

That is, the gist of the present invention is as follows.
[1] Contains a compound represented by the following formula (1), a compound represented by the following formula (2) having a longer maximum emission wavelength than the compound represented by the following formula (1), and a solvent. Composition for organic electroluminescent device.

[In the above formula, R ^{1 to} R ⁴ are independently alkyl groups having 1 to 20 carbon atoms and 7 carbon atoms, respectively.
~ 40 (hetero) aralkyl groups, 1 to 20 carbon alkoxy groups, 3 to 20 carbon atoms (
Hetero) aryloxy group, alkylsilyl group having 1 to 20 carbon atoms, 6 to 2 carbon atoms
Arylsilyl group with 0 carbon atoms, alkylcarbonyl group with 2 to 20 carbon atoms, arylcarbonyl group with 7 to 20 carbon atoms, alkylamino group with 1 to 20 carbon atoms, arylamino group with 6 to 20 carbon atoms, or carbon number of carbon atoms. Any of 3 to 30 (hetero) aryl groups, or a combination thereof. When having a plurality of substituents, they may be the same or different. These groups may further have a substituent.

a is an integer of 0 to 4, and b and c are integers of 0 to 3.
Ring A is a pyridine ring, a pyrazine ring, a pyrimidine ring, an imidazole ring, an oxazole ring,
It is any one of a thiazole ring, a quinoline ring, an isoquinoline ring, a quinazoline ring, a quinoxaline ring, an azatriphenylene ring, and a carboline ring.
Ring A may have a substituent, and the substituents are a fluorine atom, a chlorine atom, a bromine atom, an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, and a carbon number of carbon atoms. 1-20
Alkoxy group, (hetero) aryloxy group having 3 to 20 carbon atoms, alkylsilyl group having 1 to 20 carbon atoms, arylsilyl group having 6 to 20 carbon atoms, and 2 carbon atoms. Alkoxycarbonyl groups of ~ 20, arylcarbonyl groups of 7-20 carbon atoms,
It is either 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, or a combination thereof. Also,
Adjacent substituents bonded to ring A may be bonded to each other to further form a ring.

X ¹ represents a direct bond or CR ¹² R ¹³ .
Independently, R ¹² and R ¹³ have a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and 3 to 20 carbon atoms.
(Hetero) aryloxy group, alkylsilyl group having 1 to 20 carbon atoms, 6 carbon atoms
Arylsilyl group having ~ 20 carbonyl group, alkylcarbonyl group having 2 to 20 carbon atoms, 7 to 2 carbon atoms
Represents an arylcarbonyl group of 0, an alkylamino group of 1 to 20 carbon atoms, an arylamino group of 6 to 20 carbon atoms, or a (hetero) aryl group of 3 to 30 carbon atoms, but these groups further comprise a substituent. You may have.

L ¹ represents an auxiliary ligand, and m is an integer of 1 to 3. When there are a plurality of co-ligands, they may be different or the same. ]

[In formula (2), R ⁵ is an alkyl group having 1 to 20 carbon atoms and 7 to 4 carbon atoms, respectively.
A (hetero) aralkyl group of 0, 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, and 6 to 20 carbon atoms. Arylsilyl group, alkylcarbonyl group with 2 to 20 carbon atoms, arylcarbonyl group with 7 to 20 carbon atoms, alkylamino group with 1 to 20 carbon atoms, arylamino group with 6 to 20 carbon atoms, or 3 to 30 carbon atoms Any (hetero) aryl group of, or a combination thereof. These groups may further have a substituent.

d is an integer from 0 to 4.
Ring B is a pyridine ring, a pyrazine ring, a pyrimidine ring, an imidazole ring, an oxazole ring,
It is any one of a thiazole ring, a quinoline ring, an isoquinoline ring, a quinazoline ring, a quinoxaline ring, an azatriphenylene ring, and a carboline ring.
Ring B may have a substituent, and the substituents are a fluorine atom, a chlorine atom, a bromine atom, an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, and a carbon number of carbon atoms. 1-20
Alkoxy group, (hetero) aryloxy group having 3 to 20 carbon atoms, alkylsilyl group having 1 to 20 carbon atoms, arylsilyl group having 6 to 20 carbon atoms, and 2 carbon atoms. Alkoxycarbonyl groups of ~ 20, arylcarbonyl groups of 7-20 carbon atoms,
It is either 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, or a combination thereof. When having a plurality of substituents, they may be the same or different. Further, adjacent substituents bonded to the ring A may be bonded to each other to further form a ring.

L ² represents an auxiliary ligand, and n is an integer of 1 to 3. When there are a plurality of co-ligands, they may be different or the same. ]
[2] The composition for an organic electroluminescent device according to [1], wherein the formula (1) contains a compound represented by the formula (1-1).

[In the formula (1-1), R ^{1 to} R ⁴ , a, b, c, rings A, L ¹ , and m are R ¹ in the formula (1).
It is synonymous with ~ R ⁴ , a, b, c, rings A, L ¹ , m. ]
[3] The composition for an organic electroluminescent device according to [2], wherein the formula (1-1) contains a compound represented by the formula (1-2).

[In the above formula (1-2), R ^{1 to} R ⁴ , a, b, c, rings A, L ¹ , m are R ^{1 to} R ⁴ , a, b, c, in the formula (1-1). It is synonymous with rings A, L ¹ , and m. ]
[4] The composition for an organic electroluminescent device according to any one of [1] to [3], wherein m in the formula (1) is 3.
[5] Any one of claims 1 to 3, wherein m in the formula (1) is less than 3, and L ¹ has at least one of the formulas (3), (4), and (5). The composition for an organic electroluminescent device according to.

[In the above formulas (3), (4) and (5), R ⁶ and R ⁷ are synonymous with the above R ^{1 to} R ⁴ . ]
[6] An organic electroluminescent device having a light emitting layer formed by using the organic electroluminescent device composition according to any one of [1] to [5].
[7] A display device having the organic electroluminescent device according to [6].
[8] A lighting device having the organic electroluminescent element according to [7].

INDUSTRIAL APPLICABILITY According to the present invention, an organic electroluminescent device can be produced by a wet film forming method, and an organic electroluminescent device having a lower driving voltage and a longer driving life can be provided.

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

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments, and can be variously modified and implemented within the scope of the gist thereof.
In the present specification, the (hetero) aralkyl group, the (hetero) aryloxy group, and the (hetero) aryl group are an aralkyl group that may contain a heteroatom and an aryloxy group that may contain a heteroatom, respectively. Represents an aryl group, which may contain a heteroatom. "May contain a heteroatom" means that one or more carbon atoms forming the main skeleton of an aryl group, an aralkyl group or an aryloxy group are substituted with a heteroatom. , Heteroatoms include nitrogen atom, oxygen atom, sulfur atom, phosphorus atom,
Examples thereof include a silicon atom, and a nitrogen atom is particularly preferable from the viewpoint of durability.

[Hole transport assisted dopant]
The composition for an organic electroluminescent device of the present invention contains a compound represented by the following formula (1) as a hole transporting assist dopant.

[In the above formula, R ^{1 to} R ⁴ are independently alkyl groups having 1 to 20 carbon atoms and 7 carbon atoms, respectively.
~ 40 (hetero) aralkyl groups, 1 to 20 carbon alkoxy groups, 3 to 20 carbon atoms (
Hetero) aryloxy group, alkylsilyl group having 1 to 20 carbon atoms, 6 to 2 carbon atoms
Arylsilyl group with 0 carbon atoms, alkylcarbonyl group with 2 to 20 carbon atoms, arylcarbonyl group with 7 to 20 carbon atoms, alkylamino group with 1 to 20 carbon atoms, arylamino group with 6 to 20 carbon atoms, or carbon number of carbon atoms. Any of 3 to 30 (hetero) aryl groups, or a combination thereof. When having a plurality of substituents, they may be the same or different. These groups may further have a substituent.

a is an integer of 0 to 4, and b and c are integers of 0 to 3.
Ring A is a pyridine ring, a pyrazine ring, a pyrimidine ring, an imidazole ring, an oxazole ring,
It is any one of a thiazole ring, a quinoline ring, an isoquinoline ring, a quinazoline ring, a quinoxaline ring, an azatriphenylene ring, and a carboline ring.
Ring A may have a substituent, and the substituents are a fluorine atom, a chlorine atom, a bromine atom, an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, and a carbon number of carbon atoms. 1-20
Alkoxy group, (hetero) aryloxy group having 3 to 20 carbon atoms, alkylsilyl group having 1 to 20 carbon atoms, arylsilyl group having 6 to 20 carbon atoms, and 2 carbon atoms. Alkoxycarbonyl groups of ~ 20, arylcarbonyl groups of 7-20 carbon atoms,
It is either 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, or a combination thereof. Also,
Adjacent substituents bonded to ring A may be bonded to each other to further form a ring.

X ¹ represents a direct bond or CR ¹² R ¹³ .
Independently, R ¹² and R ¹³ have a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and 3 to 20 carbon atoms.
(Hetero) aryloxy group, alkylsilyl group having 1 to 20 carbon atoms, 6 carbon atoms
Arylsilyl group having ~ 20 carbonyl group, alkylcarbonyl group having 2 to 20 carbon atoms, 7 to 2 carbon atoms
Represents an arylcarbonyl group of 0, an alkylamino group of 1 to 20 carbon atoms, an arylamino group of 6 to 20 carbon atoms, or a (hetero) aryl group of 3 to 30 carbon atoms, but these groups further comprise a substituent. You may have.

L ¹ represents an auxiliary ligand, and m is an integer of 1 to 3. When there are a plurality of co-ligands, they may be different or the same. ]

[In formula (2), R ⁵ is an alkyl group having 1 to 20 carbon atoms and 7 to 4 carbon atoms, respectively.
A (hetero) aralkyl group of 0, 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, and 6 to 20 carbon atoms. Arylsilyl group, alkylcarbonyl group with 2 to 20 carbon atoms, arylcarbonyl group with 7 to 20 carbon atoms, alkylamino group with 1 to 20 carbon atoms, arylamino group with 6 to 20 carbon atoms, or 3 to 30 carbon atoms Any (hetero) aryl group of, or a combination thereof. These groups may further have a substituent.

d is an integer from 0 to 4.
Ring B is a pyridine ring, a pyrazine ring, a pyrimidine ring, an imidazole ring, an oxazole ring,
It is any one of a thiazole ring, a quinoline ring, an isoquinoline ring, a quinazoline ring, a quinoxaline ring, an azatriphenylene ring, and a carboline ring.
Ring B may have a substituent, and the substituents are a fluorine atom, a chlorine atom, a bromine atom, an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, and a carbon number of carbon atoms. 1-20
Alkoxy group, (hetero) aryloxy group having 3 to 20 carbon atoms, alkylsilyl group having 1 to 20 carbon atoms, arylsilyl group having 6 to 20 carbon atoms, and 2 carbon atoms. Alkoxycarbonyl groups of ~ 20, arylcarbonyl groups of 7-20 carbon atoms,
It is either 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, or a combination thereof. When having a plurality of substituents, they may be the same or different. Further, adjacent substituents bonded to the ring A may be bonded to each other to further form a ring.

L ² represents an auxiliary ligand, and n is an integer of 1 to 3. When there are a plurality of co-ligands, they may be different or the same. ]
From the viewpoint of durability, R ^{1 to} R ⁴ are 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. More preferably, it is an alkyl group having 1 to 20 carbon atoms and 7 to 20 carbon atoms.
It is more preferable that it is a (hetero) aralkyl group of 40 or a (hetero) aryl group having 3 to 20 carbon atoms. A is preferably 0 in terms of ease of production, and the hole transportability is further enhanced. It is preferably 1 or 2 in terms of enhancing solubility, and more preferably 1. b and c are preferably 0 in terms of ease of production, and preferably 1 in terms of further enhancing hole transportability and enhancing solubility.

As the ring A, an aromatic ring or an aromatic heterocycle can be used. These include pyridine ring, pyrimidine ring, imidazole ring, quinoline ring, isoquinoline ring, quinazoline ring,
It is any one of a quinoxaline ring, an azatriphenylene ring, and a carboline ring, and a pyridine ring is more preferable from the viewpoint of durability. Any of quinoline ring, isoquinoline ring, quinazoline ring, quinoxaline ring, azatriphenylene ring, and carboline ring is preferable in that excitons are easily generated on the hole transporting assist dopant and the luminous efficiency is enhanced. .. Of these, any of a quinoline ring, an isoquinoline ring, and a quinazoline ring is preferable in terms of durability.

The hydrogen atom on the ring A has an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, and a (hetero) aralkyl group having 3 to 20 carbon atoms in terms of durability and enhanced solubility. It is preferably substituted with a hetero) aryl group. Further, it is preferable that the hydrogen atom on the ring A is not substituted in terms of ease of production. When the hydrogen atom on the ring A is substituted with a phenyl group or a naphthyl group which may have a substituent, excitons are easily generated on the hole transporting assist dopant, so that the luminous efficiency is improved. Preferred in terms of points.

Adjacent substituents attached to ring A may be bonded to each other to form a further ring. Further, the substituent may further have a substituent.
Since there are many structures having a high hole transport property including a carbazole ring, m 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 more preferably selected from the following chemical formulas. The broken line in the chemical formula represents a coordination bond. 2
One of the case where the organic ligand L ¹ is present, the organic ligand L ¹ may be different structures from each other. Also, when m is 3, L ¹ does not exist.

When m in the formula (1) is less than 3, for example, L ¹ has at least one of the formula (3), the formula (4), and the formula (5).

In the above formulas (3), (4) and (5), R ⁶ and R ⁷ are selected from the same group as the substituents that can be selected as R ^{1 to} R ⁴ , and the preferred examples are also the same. e and f are preferably 0 in terms of ease of production, preferably 1 or 2 in terms of enhancing solubility, and even more preferably 1.
R ⁸ to R ¹⁰ 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. Represents an atom. More preferably, R ⁸ and R ¹⁰ are methyl or t-butyl groups, and R ⁹ is a hydrogen atom or an alkyl or phenyl group having 1 to 20 carbon atoms.

The hole transporting assist dopant contained in the composition for an organic electroluminescent device of the present invention has the formula (
It is more preferable from the viewpoint of durability that X ^{1 in} 1) is a direct bond to form a carbazole ring, that is, a compound represented by the formula (1-1).

[In the above formula (1-1), R ^{1 to} R ⁴ , a, b, c, rings A, L ¹ , m are R ^{1 to} R ⁴ , a, b, c, ring A in the formula (1). , L ¹ , and m. ]
Formula (1-1) ^R 1 ^{to R} 4 in the, a, b, c, preferred examples of the ring ^{A, L} 1, m is, ^R 1 ^{to R} 4 in Formula (1) described above, a, b, c , Rings A, L ¹ , and m.
Further, the hole transporting assist dopant contained in the composition for an organic electroluminescent device of the present invention is represented by the formula (1-2), in which the 3-position of the carbazole ring is bonded to a phenyl group bonded to iridium. It is preferable that the structure has high durability and high charge transporting ability.

[In the above formula (1-2), R ^{1 to} R ⁴ , a, b, c, rings A, L ¹ , m are R ^{1 to} R ⁴ , a, b, c, in the formula (1-1). It is synonymous with rings A, L ¹ , and m. ]
Formula (1-2) ^R 1 ^{to R} 4 in the, a, b, c, preferred examples of the ring ^{A, L} 1, m is, ^R 1 ^{to R} 4 in Formula (1) described above, a, b, c , Rings A, L ¹ , and m.
Preferred specific examples of the hole transporting assist dopant are shown below, but the present invention is not limited thereto.

[Luminous dopant]
The composition for an organic electroluminescent device of the present invention contains a compound represented by the following formula (2) as a luminescent dopant. The luminescent dopant has a longer maximum emission wavelength than the hole transporting assist dopant described above. Therefore, when the hole transporting assist dopant is in the excited state, energy is transferred to the luminescent dopant having a smaller excitation energy. Therefore, after the luminescent dopant is in the excited state, the luminescent dopant emits light. Can be observed.

[In the above formula (2), R ⁵ is an alkyl group having 1 to 20 carbon atoms and 7 carbon atoms, respectively.
~ 40 (hetero) aralkyl groups, 1 to 20 carbon alkoxy groups, 3 to 20 carbon atoms (
Hetero) aryloxy group, alkylsilyl group having 1 to 20 carbon atoms, 6 to 2 carbon atoms
Arylsilyl group with 0 carbon atoms, alkylcarbonyl group with 2 to 20 carbon atoms, arylcarbonyl group with 7 to 20 carbon atoms, alkylamino group with 1 to 20 carbon atoms, arylamino group with 6 to 20 carbon atoms, or carbon number of carbon atoms. Any of 3 to 30 (hetero) aryl groups, or a combination thereof. These groups may further have a substituent.

d is an integer from 0 to 4.
Ring B is a pyridine ring, a pyrazine ring, a pyrimidine ring, an imidazole ring, an oxazole ring,
It is any one of a thiazole ring, a quinoline ring, an isoquinoline ring, a quinazoline ring, a quinoxaline ring, an azatriphenylene ring, and a carboline ring.
Ring B may have a substituent, and the substituents are a fluorine atom, a chlorine atom, a bromine atom, an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, and a carbon number of carbon atoms. 1-20
Alkoxy group, (hetero) aryloxy group having 3 to 20 carbon atoms, alkylsilyl group having 1 to 20 carbon atoms, arylsilyl group having 6 to 20 carbon atoms, and 2 carbon atoms. Alkoxycarbonyl groups of ~ 20, arylcarbonyl groups of 7-20 carbon atoms,
It is either 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, or a combination thereof. When having a plurality of substituents, they may be the same or different. Further, adjacent substituents bonded to the ring A may be bonded to each other to further form a ring.

L ² represents an organic ligand, and n is an integer of 1 to 3. ]
From the viewpoint of durability, R ⁵ is an alkyl group having 1 to 20 carbon atoms and (hetero) having 7 to 40 carbon atoms.
Aralkyl group, arylamino group with 6 to 20 carbon atoms, or (hetero) with 3 to 30 carbon atoms
More preferably an aryl group, an alkyl group having 1 to 20 carbon atoms, of 7 to 40 carbon atoms (hetero) aralkyl group, or having 3 to 20 carbon atoms and more preferably R ⁵ be a (hetero) aryl group A phenyl group which may have a substituent from the viewpoint of durability and solubility.
It is preferable to bond to the m-position of ring B and the p-position of iridium. That is, the equation (2) is
It is more preferable that the compound is represented by the following formula (2-1).

[In the above formula (2-1), R ¹¹ independently has an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and carbon. Number 3-2
0 (hetero) aryloxy group, alkylsilyl group having 1 to 20 carbon atoms, arylsilyl group having 6 to 20 carbon atoms, alkylcarbonyl group having 2 to 20 carbon atoms, 7 to 20 carbon atoms
Represents an arylcarbonyl group of 20, an alkylamino group having 1 to 20 carbon atoms, an arylamino group having 6 to 20 carbon atoms, or a (hetero) aryl group having 3 to 30 carbon atoms, but these groups further comprise a substituent. You may have. g is an integer from 0 to 4. ]
g is preferably 0 in terms of ease of production, preferably 1 or 2 in terms of durability and enhancement of solubility, and even more preferably 1.

From the viewpoint of durability, the ring B is preferably a pyridine ring, a pyrimidine ring, or an imidazole ring, and more preferably a pyridine ring. In addition, quinoline ring, isoquinoline ring, quinazoline ring, quinoxaline ring, azatriphenylene ring, and carboline ring are preferable in that excitons are easily generated on the hole transporting assist dopant and the light emission efficiency is enhanced. A quinoline ring, an isoquinoline ring, and a quinazoline ring are particularly preferable in terms of sex and red emission.

The hydrogen atom on the ring B has an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, and a (hetero) having 3 to 20 carbon atoms in terms of durability and enhanced solubility. ) It is preferably substituted with an aryl group. Further, it is preferable that the hydrogen atom on the ring B is not substituted because it is easy to produce. When the hydrogen atom on the ring B is substituted with a phenyl group or a naphthyl group which may have a substituent, excitons are easily generated when it is used as an organic electroluminescent element, so that the luminous efficiency Is preferable in that

Adjacent substituents bonded to ring B may be bonded to each other to further form a ring. L ² is an organic ligand and is not particularly limited, but is preferably a monovalent bidentate ligand, and a more preferable example is the same as that shown as a preferable example of L ¹ . Two organic ligands L ²
There When present, organic ligand L ² may have different structures from each other. Also, n is 3
In the case of, L ² does not exist.

Specific examples of the luminescent dopant are shown below, but the present invention is not limited thereto.

As an example of the combination of the hole transporting assist dopant and the luminescent dopant, a compound obtained by appropriately combining any compound of the hole transporting assist dopant specific example described above and any compound of the luminescent dopant specific example described above is appropriately combined. Can be used.
[Specific example of substituent]
The alkyl group having 1 to 20 carbon atoms may be a linear, branched or cyclic alkyl group, and more specifically, a methyl group, an ethyl group, an n-propyl group, an n-butyl group, or n.
-Pentyl group, n-hexyl group, n-octyl group, isopropyl group, isobutyl group, isopentyl group, t-butyl group, cyclohexyl group and the like can be mentioned. Of these, a linear alkyl group having 1 to 8 carbon atoms such as a methyl group, an ethyl group, an n-butyl group, an n-hexyl group and an n-octyl group is preferable.

As a specific example of the (hetero) aralkyl group having 7 to 40 carbon atoms, a linear alkyl group, a branched alkyl group, and a part of hydrogen atoms constituting a cyclic alkyl group are substituted with a (hetero) aryl group. More specifically, 2-phenyl-1-ethyl group, cumyl group, 5-phenyl-1-pentyl group, 6-phenyl-1-hexyl group, 7-phenyl-
Examples include 1-heptyl group and tetrahydronaphthyl group. Above all, 5-phenyl-1
-Pentyl group, 6-phenyl-1-hexyl group and 7-phenyl-1-heptyl group are preferable.

Specific examples of the alkoxy group having 1 to 20 carbon atoms 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. Of these, a hexyloxy group is preferable.
Specific examples of the (hetero) aryloxy group having 3 to 20 carbon atoms include a phenoxy group.
Examples include 4-methylphenyloxy groups. Of these, a phenoxy group is preferable.

Specific examples of the alkylsilyl group having 1 to 20 carbon atoms include a trimethylsilyl group.
Examples thereof include a triethylsilyl group, a triisopropylsilyl group, a dimethylphenyl group, a t-butyldimethylsilyl group and a t-butyldiphenylsilyl group, among which the triisopropyl group, the t-butyldimethylsilyl group and the t-butyldiphenylsilyl group are used. preferable.
Specific examples of the arylsilyl group having 6 to 20 carbon atoms include a diphenylpyridylsilyl group and a triphenylsilyl group, and a triphenylsilyl group is preferable.

Specific examples of the alkylcarbonyl group having 2 to 20 carbon atoms include an acetyl group, a propionyl group, a pivaloyl group, a caproyl group, a decanoyle group, a cyclohexylcarbonyl group and the like, and an acetyl group and a pivaloyl group are preferable.
Specific examples of the arylcarbonyl group having 7 to 20 carbon atoms include a benzoyl group, a naphthoyl group, an antryl group and the like, and a benzoyl group is preferable.

Specific examples of the alkylamino group having 1 to 20 carbon atoms include a methylamino group, a dimethylamino group, a diethylamino group, an ethylmethylamino group, a dihexylamino group, a dioctylamino group, a dicyclohexylamino group and the like, and among them, dimethyl. Amino groups and dicyclohexylamino groups are preferable.
Specific examples of the arylamino group having 6 to 20 carbon atoms include a phenylamino group, a diphenylamino group, a di (4-tolyl) amino group, a di (2,6-dimethylphenyl) amino group, and the like. A diphenylamino group and a di (4-tolyl) amino group are preferable.

The (hetero) aryl group having 3 to 30 carbon atoms means an aromatic hydrocarbon group and an aromatic heterocyclic group having one free valence, or a series of a plurality of aromatic hydrocarbons. ..
Specific examples 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, a fluorantene ring, and a furan ring, which have one free valence. Benzofuran ring, dibenzofuran ring, thiophene ring, benzothiophene ring, dibenzothiophene ring, pyrrol ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, pyrrolomidazole ring, pyrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole Ring, thienothiophene ring, flopilol ring, flofuran ring, thienoflan ring, benzoisoxazole ring, benzoisothiazole ring, benzimidazole ring, pyridine ring, pyrazine ring, pyridazine ring, pyrimidine ring, triazine ring, quinoline ring, isoquinoline ring, Cynoline ring,
Examples include groups such as a quinoxaline ring, a perimidine ring, a quinazoline ring, a quinazolinone ring, and an azulene ring. Examples of the group in which a plurality of aromatic hydrocarbons are linked include a biphenyl group, a terphenyl group, and the like.

Among the (hetero) aryl groups, a benzene ring, a naphthalene ring, a dibenzofuran ring, a dibenzothiophene ring, a carbazole ring, a pyridine ring, a pyrimidine ring, and a triazine ring having one free valence are preferable from the viewpoint of durability. Among them, it has one free valence and
It has an aryl group having 6 to 18 carbon atoms, such as a benzene ring, a naphthalene ring or a phenanthrene ring, which may be substituted with an alkyl group having 1 to 8 carbon atoms, or one free valence.
A pyridine ring which may be substituted with an alkyl group having 1 to 4 carbon atoms is more preferable, and a benzene ring which has one free atomic value and may be substituted with an alkyl group having 1 to 8 carbon atoms is preferable. , Aryl group having 6 to 18 carbon atoms such as a naphthalene ring or a phenanthrene ring is more preferable.

Examples of the combination of these substituents include a combination of an aryl group and an alkyl group.
A combination of an aryl group and an aralkyl group, or a combination of an aryl group and an alkyl group or an aralkyl group can be used.
As the combination of the aryl group and the aralkyl group, for example, a combination of a benzene, a biphenyl group, a terphenyl group, a 5-phenyl-1-pentyl group, and a 6-phenyl-1-hexyl group can be used. Further, from the viewpoint of increasing the luminous efficiency by lengthening the conjugation more than necessary, it is preferable to provide a methyl group in, for example, an aryl group adjacent to the ring A and the ring B.

[Maximum emission wavelength]
The method for measuring the maximum emission wavelength in the present invention is shown below.
Phosphorescence spectrum of a solution prepared by dissolving a compound in 2-methyl tetrahydrofuran at a concentration of 1 × 10 ^-4 mol / L or less at room temperature with a spectrophotometer (organic EL quantum yield measuring device C9920-02 manufactured by Hamamatsu Photonics Co., Ltd.). To measure. The wavelength indicating the maximum value of the obtained phosphorescence spectral intensity is defined as the maximum emission wavelength.

The luminescent dopant contained in the composition for an organic electroluminescent device of the present invention has a longer maximum emission wavelength than the hole transporting assist dopant.
The maximum emission wavelength of the luminescent dopant is preferably 580 nm or more, more preferably 590 nm or more, further preferably 600 nm or more, preferably 700 nm or less, and preferably 680 nm.
The following is more preferable. When the maximum emission wavelength is in this range, it tends to be possible to express a preferable color of a red light emitting material suitable as an organic electroluminescent element.

What is the maximum wavelength of the hole transporting assist dopant and the maximum wavelength of the luminescent dopant?
It is preferably separated by 10 nm or more.
Further, the luminescent dopant represented by the formula (2) has a mol concentration of 1 to 4 times, preferably 2 to 3 times that of the hole transporting assist dopant represented by the formula (1). preferable. As a result, the energy from the hole transporting assist dopant is transferred to the luminescent dopant with a high probability, so that the hole transporting assist dopant is less likely to emit light directly, and higher luminous efficiency can be obtained.

[Method for synthesizing iridium complex compound]
The hole transporting assist dopant and the luminescent dopant contained in the composition for an organic electroluminescent device of the present invention are iridium complex compounds. The method for synthesizing the iridium complex compound is shown below.
The ligand of the iridium complex compound can be synthesized by a combination of known methods and the like.
Ligand synthesis is performed by Suzuki-Miyaura coupling reaction between arylboronic acids and halogenated heteroaryls, Friedlayer cyclization reaction with 2-formyl or acylanilines, or acyl-aminopyridines in ortho positions with each other. (Chem. Rev. 20
09, 109, 2652, or Organic Reactions, 28 (2), 3
It can be synthesized by a known reaction such as 7-201).

<Method for synthesizing iridium complex compound>
The iridium complex compound can be synthesized by a combination of known methods using a ligand and iridium chloride n hydrate as raw materials. This will be described below.
As a method for synthesizing the iridium complex compound, a method via a chlorine-crosslinked iridium binuclear complex as shown in the following formula [A] using a phenylpyridine ligand as an example for easy understanding (MG Colombo). , TC Brunold, TC Riedener, HU
.. GudelInorg. Chem. , 1994, 33, 545-550), the following equation [B
] A method for obtaining a desired product after further exchanging chlorine crosslinks with acetylacetonate from a dikaryon complex to a mononuclear complex (S. Lamansky, P. Djurovich, D. Murph).
y, F. Abdel-Razzaq, R.M. Kwon, I.K. Tsyba, M. et al. Borz,
B. Mui, R.M. Bau, M.M. Thomasson, Inorg. Chem. , 20011,
40,1704-1711) and the like can be exemplified, but the present invention is not limited thereto.

For example, the typical reaction conditions represented by the following formula [A] are as follows.
As a first step, a chlorine-crosslinked iridium binuclear complex is synthesized by a reaction of 2 equivalents of the first ligand and 1 equivalent of iridium chloride n hydrate. As the solvent, a mixed solvent of 2-ethoxyethanol and water is usually used, but a solvent-free solvent or another solvent may be used. Excessive amount of ligand
The reaction can also be promoted by using an additive such as a base. Other crosslinkable anionic ligands such as bromine can be used instead of chlorine.

The reaction temperature is not particularly limited, but usually 0 ° C. or higher is preferable, and 50 ° C. or higher is more preferable. Further, 250 ° C. or lower is preferable, and 150 ° C. or lower is more preferable. When the reaction temperature is within this range, only the desired reaction proceeds without accompanying by-products or decomposition reactions, and high selectivity tends to be obtained.

In the second step, a halogen ion scavenger such as silver trifluoromethanesulfonate is added and brought into contact with the second ligand to obtain the desired complex. Although ethoxyethanol or diglyme is usually used as the solvent, no solvent or other solvent can be used depending on the type of ligand, and a plurality of solvents can be mixed and used. It is not always necessary because the reaction may proceed without the addition of a halogen ion scavenger, but it increases the reaction yield and increases the reaction yield.
The addition of the scavenger is advantageous for the selective synthesis of facial isomers with higher quantum yields. The reaction temperature is not particularly limited, but is usually carried out in the range of 0 ° C. to 250 ° C.

The typical reaction conditions represented by the following formula [B] will be described.
The first-stage dikaryon complex can be synthesized in the same manner as in the formula [A].
In the second step, one equivalent or more of a 1,3-dione compound such as acetylacetone and a basic compound capable of extracting active hydrogen of the 1,3-dione compound such as sodium carbonate are added to the dinuclear complex. By reacting in an equivalent amount or more, it is converted into a mononuclear complex in which the 1,3-dionat ligand is coordinated. Usually, a solvent such as ethoxyethanol or dichloromethane that can dissolve the dinuclear complex of the raw material is used, but if the ligand is liquid, it can be carried out without a solvent. The reaction temperature is not particularly limited, but is usually carried out in the range of 0 ° C. to 200 ° C.

The third step is to react one or more equivalents of the second ligand. The type and amount of the solvent are not particularly limited, and may be solvent-free as long as the second ligand is liquid at the reaction temperature. The reaction temperature is also not particularly limited, but since the reactivity is slightly poor, the reaction is often carried out at a relatively high temperature of 100 ° C. to 300 ° C. Therefore, a solvent having a high boiling point such as glycerin is preferably used.
After the final reaction, purification is performed to remove unreacted raw materials, reaction by-products and solvents. Purification operations in ordinary synthetic organic chemistry can be applied, but purification is mainly performed by normal phase silica gel column chromatography as described in the above non-patent documents. A single or mixed solution of hexane, heptane, dichloromethane, chloroform, ethyl acetate, toluene, methyl ethyl ketone, and methanol can be used as the developing solution. Purification may be performed multiple times under different conditions. Other chromatography techniques (reverse phase silica gel chromatography, size exclusion chromatography, paper chromatography) and purification operations such as liquid separation washing, reprecipitation, recrystallization, suspension washing of powder, and vacuum drying are required. Can be applied.

[solvent]
The composition for an organic electroluminescent device of the present invention contains a solvent.
The composition for an organic electroluminescent device of the present invention is usually used for forming a layer or a film by a wet film forming method, and is particularly preferably used for forming a light emitting layer of an organic electroluminescent device.
The content of the hole transporting assist dopant in the composition for an organic electroluminescent device is usually 0.01% by weight or more, preferably 0.1% by weight or more, usually 20% by weight or less, preferably 1.
It is 0% by weight or less. By setting the content of the hole transporting assist dopant in this range, when the composition is used for an organic electroluminescent device, light is emitted from an adjacent layer (for example, a hole transporting layer or a hole blocking layer). Holes and electrons are efficiently injected into the layer, and the driving voltage can be reduced.

The composition for an organic electroluminescent device may contain only one type of hole transporting assist dopant, or may contain two or more types in combination.
The content of the luminescent dopant in the composition for an organic electroluminescent device is usually 0.01% by weight or more, preferably 0.1% by weight or more, usually 20% by weight or less, preferably 10% by weight or less. By setting the content of the luminescent dopant in this range, the excitation energy moves to an adjacent layer (for example, a hole transport layer or a hole blocking layer) when the composition is used for an organic electroluminescent device application. It is possible to improve the light emission efficiency because it is less likely to be extinguished due to the interaction between excitons.

If the composition for an organic electroluminescent device contains two or more types of luminescent dopants,
The dopant having the longest maximum emission wavelength is used as the luminescent dopant in the present invention.
The ratio of the content of the hole transporting assist dopant to the content of the light emitting dopant in the composition for the organic electroluminescent device is that the hole transporting assist dopant is superior in that the driving voltage can be further reduced. A large amount is preferable, and a large amount of luminescent dopant is preferable in that the width of the emission spectrum is narrowed and vivid light emission can be obtained.

The solvent contained in the composition for an organic electroluminescent device of the present invention is a volatile liquid component used for forming a layer containing a hole transporting assist dopant and a luminescent dopant by wet film formation.
The solvent is not particularly limited as long as it is a solvent in which the hole transporting assist dopant and the luminescent dopant, which are solutes, dissolve well. Further, it is preferably a solvent that dissolves a charge transporting compound described later. Preferred solvents include, for example, alkanes such as n-decane, cyclohexane, ethylcyclohexane, decalin and bicyclohexane; aromatic hydrocarbons such as toluene, xylene, mesitylene, phenylcyclohexane and tetralin; chlorobenzene, dichlorobenzene and trichlorobenzene. Halogenized aromatic hydrocarbons such as; 1, 2,
-Dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetol, 2-
Aromatic ethers such as methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, diphenyl ether; phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, Aromatic esters such as propyl benzoate and n-butyl benzoate; cyclohexanone, cyclooctanone,
Alicyclic ketones such as fencon; alicyclic alcohols such as cyclohexanol and cyclooctanol; aliphatic ketones such as methyl ethyl ketone and dibutyl ketone; aliphatic alcohols such as butanol and hexanol; ethylene glycol dimethyl ether and ethylene glycol diethyl Examples thereof include ethers and aliphatic ethers such as propylene glycol-1-monomethyl ether acetate (PGMEA). Of these, alkanes and aromatic hydrocarbons are preferable, and phenylcyclohexane in particular has a preferable viscosity and boiling point in the wet film forming process.

One of these solvents may be used alone, or two or more of these solvents may be used in any combination and ratio.
The boiling point of the solvent is usually 80 ° C. or higher, preferably 100 ° C. or higher, more preferably 150 ° C. or higher, and particularly preferably 200 ° C. or higher. In addition, the boiling point is usually 270 ° C. or lower, preferably 25.
It is 0 ° C. or lower, more preferably 240 ° C. or lower. If it falls below this range, the film formation stability may decrease due to solvent evaporation from the composition during wet film formation.

The content of the solvent is preferably 10 parts by weight or more, more preferably 50 parts by weight or more, particularly preferably 80 parts by weight or more, and preferably 99 parts by weight or more, based on 100 parts by weight of the composition.
It is 95 parts by weight or less, more preferably 99.9 parts by weight or less, and particularly preferably 99.8 parts by weight or less.
Normally, the thickness of the light emitting layer is about 3 to 200 nm, but if the solvent content is less than this lower limit, the viscosity of the composition becomes too high, and the film forming workability may decrease. On the other hand, if this upper limit is exceeded, the thickness of the film obtained by removing the solvent after the film formation cannot be increased, so that the film formation tends to be difficult.

[Charge transporting compound]
The composition for an organic electroluminescent device of the present invention preferably contains a charge transporting compound.
As the charge transporting compound, a compound conventionally used as a material for an organic electroluminescent device can be used. For example, triarylamine, biscarbazole, triaryltriazine, triarylpyrimidine and derivatives thereof, naphthalene, perylene, pyrene, anthracene, chrysene, naphthalene, phenanthrene, coronene, fluoranthene, benzo substituted with arylamino group or carbazolyl group. Phenanthrene, Fluoranthrene,
Condensed aromatic ring compounds such as acetonaphthofluoranthen can be mentioned.

Further, the charge transporting compound may be a polymer, and the polymer charge transporting compound includes 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, poly [2-methoxy-5- (2-hetylhexyloxy) -1,4-phenylene vinylene. ] And other polyphenylene vinylene-based materials.

One of these charge transporting compounds may be used alone, or two or more of these may be used in any combination and ratio.
[Organic electroluminescent device]
The organic electroluminescent device of the present invention includes a layer formed by a wet film forming method using the composition for an organic electroluminescent device of the present invention.

The organic electroluminescent element of the present invention preferably has at least an anode, a cathode, and at least one organic layer between the anode and the cathode on a substrate, and at least one of the organic layers is the present invention. Includes a layer formed by a wet film formation method using the composition for an organic electroluminescent element of.
The organic layer includes a light emitting layer.
The layer formed by the wet film formation method using the composition for an organic electroluminescent device of the present invention is preferably a light emitting layer.

In the present invention, 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 a capillary. We adopt methods such as coating method, inkjet method, nozzle printing method, screen printing method, gravure printing method, flexographic printing method, etc., and dry the film formed by these methods to form a film. The way to do it.

FIG. 1 is a schematic cross-sectional view showing a structural example suitable for the organic electroluminescent device 10 of the present invention. Figure 1
In the above, reference numeral 1 is a substrate, reference numeral 2 is an anode, reference numeral 3 is a hole injection layer, reference numeral 4 is a hole transport layer, reference numeral 5 is a light emitting layer, reference numeral 6 is a hole blocking layer, and reference numeral 7 is an electron transport layer. 8 is an electron injection layer, reference numeral 9
Represent each cathode.
As the material applied to these structures, known materials can be applied, and there is no particular limitation, but typical materials and manufacturing methods for each layer are described below as an example. In the following, when citations of publications, papers, etc., the relevant contents can be applied and applied as appropriate within the scope of common sense of those skilled in the art.

<Board 1>
The substrate 1 serves as a support for an organic electroluminescent element, and usually a quartz or glass plate, a metal plate or a metal foil, a plastic film, a sheet, or the like is used. Of these, glass plates and transparent synthetic resin plates such as polyester, polymethacrylate, polycarbonate, and polysulfone are preferable. The substrate 1 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. In particular, 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 1 to improve the gas barrier property.

<Anode 2>
The anode 2 has a function of injecting holes into the layer on the light emitting layer 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 or 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 the anode 2 is formed using metal fine particles such as silver, fine particles such as copper iodide, carbon black, conductive metal oxide fine particles, conductive polymer fine powder, etc., it is dispersed in an appropriate binder resin solution. It can also be formed by applying it on a substrate. In the case of a conductive polymer, the anode 2 can be formed by directly forming a thin film on the substrate by electrolytic polymerization or by coating the conductive polymer on the substrate (Appl. Phys. Lett., Volume 60, p. 2711, 1992).

The anode 2 usually has a single-layer structure, but may have a laminated structure as appropriate. When the anode 2 has a laminated structure, different conductive materials may be laminated on the first-layer 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 1.
When forming a film on the surface of the anode 2, impurities on the anode are removed and the ionization potential thereof is adjusted by performing treatments such as ultraviolet rays + ozone, oxygen plasma, and argon plasma before the film formation. It is preferable to improve the hole injection property.

<Hole injection layer 3>
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 2 side may be referred to as the hole injection layer 3. The hole injection layer 3 is preferably used because it enhances the function of transporting holes from the anode 2 to the light emitting layer 5. When the hole injection layer 3 is used, the hole injection layer 3 is usually formed on the anode 2.

The film thickness of the hole injection layer 3 is usually 1 nm or more, preferably 5 nm or more, and usually 1000 nm.
Below, it is preferably 500 nm or less.
The hole injection layer 3 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, the hole injection layer 3 preferably contains a cation radical compound, and particularly preferably contains a cation radical compound and a hole transporting compound.

(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 forming method, a solvent is usually further contained. It is preferable that the composition for forming a hole injection layer has high hole transportability and can efficiently transport the injected holes. For this reason, it is preferable that the hole mobility is high and impurities that serve as traps are unlikely to be generated during production or use. Also,
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, 4 is used from the viewpoint of a charge injection barrier from the anode 2 to the hole injection layer 3.
.. Compounds having an ionization potential of 5 eV to 6.0 eV are preferable. 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 1,000 or more and 1,000,000 or less (a polymerized compound in which repeating units are continuous) is easy to obtain uniform light emission due to the surface smoothing effect. Is preferably used. Preferred examples of the aromatic tertiary amine polymer compound include a polymer compound having a repeating unit represented by the following formula (I).

(In the formula (I), Ar ¹ and Ar ² each independently represent an aromatic group which may have a substituent or a complex aromatic group which may have a substituent. Ar ³ ~ Ar ⁵ each independently represents an aromatic group which may have a substituent or a complex aromatic group which may have a substituent. Q is from the following linking group group. It represents the linking group of choice. Further, two groups of Ar ^{1 to} Ar ⁵ that are bonded to the same N atom may be bonded to each other to form a ring.

The linking groups are shown below.

(In the above formulas, Ar ⁶ to Ar ¹⁶ are each independently, .R represents an heteroaromatic group optionally having also an aromatic group or a substituent substituted ^a ~ R ^b independently represents a hydrogen atom or an arbitrary substituent.)
The aromatic groups and heteroaromatic groups of Ar ^{1 to} Ar ¹⁶ include benzene ring, naphthalene ring, phenanthrene ring, thiophene ring, and pyridine ring from the viewpoint of solubility, heat resistance, and hole injection transportability of the polymer compound. Derived groups are preferable, and groups derived from benzene rings and naphthalene rings are more preferable.

Specific examples of the aromatic tertiary amine polymer compound having a repeating unit represented by the formula (I) include those described in Pamphlet No. 2005/089024.
(Electron accepting compound)
The hole injection layer 3 preferably contains an electron-accepting compound because the conductivity of the hole injection layer 3 can be improved by oxidizing the hole transporting compound.

As the electron-accepting compound, a compound having an oxidizing power and having an ability to accept one electron from the above-mentioned hole transporting compound is preferable, and specifically, a compound having an electron affinity of 4 eV or more is preferable, and an electron affinity is preferable. A compound having a value of 5 eV or more is more preferable.
Such an electron-accepting compound includes, for example, 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 or more compounds selected from the group. Specifically, an onium salt substituted with an organic group such as 4-isopropyl-4'-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate, triphenylsulfonium tetrafluoroborate (International Publication No. 2005/089024); chloride. High valence inorganic compounds such as iron (III) (Japanese Patent Laid-Open No. 11-251067), ammonium peroxodisulfate; cyano compounds such as tetracyanoethylene; tris (pentafluorophenyl) borane (Japanese Patent Laid-Open No. 2003-313665) Such as aromatic boron compounds; fullerene derivatives, iodine and the like.

(Cation 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. 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 above-mentioned compound as a hole transporting compound. 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.
The cationic radical compound can be produced by mixing the hole transporting compound and the electron accepting compound described above. By mixing the above-mentioned hole-transporting compound and 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.

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 (dehydrogenation), 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 3 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 (hole injection layer solvent) 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 to a layer corresponding to the lower layer of the hole injection layer 3 (usually, an anode 2).
) Is formed by a wet film formation method and dried. The film formed can be dried in the same manner as the drying method in forming the light emitting layer 5 by the wet film forming method.

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 Layer 3
Higher is preferable in that defects are less likely to occur. The concentration of the hole transporting compound in the composition for forming a hole injection layer is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, particularly preferably 0.5% by mass or more, and 70% by mass. % Or less is preferable, 60% by mass or less is further preferable, and 50% by mass or less is particularly preferable.

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), 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, methylnaphthalene and the like.

Examples of the amide 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 after preparing the composition for forming the hole injection layer.
This is performed by coating and forming a film on a layer corresponding to the lower layer of the hole injection layer 3 (usually, the anode 2) and drying. 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 3 by vacuum deposition method)
When the hole injection layer 3 is formed by the vacuum deposition method, it is usually a constituent material of the hole injection layer 3 (
Put one or more of the above-mentioned hole-transporting compounds, electron-accepting compounds, etc.) in a crucible installed in a vacuum vessel (when using two or more materials, usually put each in a separate crucible. After exhausting the inside of the vacuum vessel to about 10-4 Pa with a vacuum pump, heat the crucible (when using two or more types of materials, usually heat each crucible), and then use the material in the crucible. Evaporate while controlling the amount of evaporation (when using two or more types of materials, usually evaporate while controlling the amount of evaporation independently), and inject holes onto the anode 2 on the substrate placed facing the crucible. Layer 3 is formed. 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 hole injection layer 3.

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 (12)
.. It is 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 during vapor deposition is
It is not limited as long as the effect of the present invention is not significantly impaired, but is preferably carried out at 10 ° C. or higher and 50 ° C. or lower.

<Hole transport layer 4>
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 is not an essential layer in the organic electroluminescent device of the present invention, but the anode 2 to the light emitting layer 5
It is preferable to provide this layer in terms of enhancing the function of transporting holes to the holes. Hole transport layer 4
The hole transport layer 4 is usually formed between the anode 2 and the light emitting layer 5. When there is a hole injection layer 3, 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, and usually 300 nm.
Below, it is 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 hole transport layer 4 usually contains a hole transport compound that becomes the hole transport layer 4. Examples of the hole-transporting compound contained in the hole-transporting layer 4 include 4,4'-bis [N- (1-naphthyl).
-N-Phenylamino] Aromatic diamine containing two or more tertiary amines represented by biphenyl and having two or more fused aromatic rings replaced with nitrogen atoms (Japanese Patent Laid-Open No. 5-234681).
, 4, 4', 4''-Tris (1-naphthylphenylamino) Aromatic amine compounds having a starburst structure such as triphenylamine (J. Lumin., Vol. 72-74, 98)
Page 5, 1997), Aromatic amine compound consisting of a tetramer of triphenylamine (Che)
m. Commun. , 2175, 1996), 2,2', 7,7'-Tetrakis- (
Spiro compounds such as diphenylamino) -9,9'-spirobifluorene (Synth.M.
etals, Vol. 91, p. 209, 1997), carbazole derivatives such as 4,4'-N, N'-dicarbazole biphenyl and the like. Polyarylene ether sulfone containing polyvinylcarbazole, polyvinyltriphenylamine (Japanese Patent Laid-Open No. 7-53953), tetraphenylbenzidine (Polym. Adv. Tech., Vol. 7, 3, 3
3 pages, 1996) and the like can also be preferably used.

(Formation of hole transport layer 4 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 forming 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 the hole-transporting layer can be in the same range as the concentration of the hole-transporting compound in the composition for forming the hole-injecting layer.
The formation of the hole transport layer 4 by the wet film forming method can be performed in the same manner as the above-mentioned film forming method of the hole injection layer 3.
(Formation of hole transport layer 4 by vacuum deposition method)
When the hole transport layer 4 is formed by the vacuum vapor deposition method, holes are usually used instead of the constituent materials 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 using the constituent materials of the 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 vapor deposition of the hole injection layer 3.

<Light emitting layer 5>
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 injection layer 3 and the cathode 9 when the hole injection layer 3 is above the anode 2, and is positive when the hole transport layer 4 is above the anode 2. It 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. 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 even more preferably 100 nm or less.
The light emitting layer 5 is preferably formed by a wet coating method using the composition for an organic electroluminescent device of the present invention.

In addition to the light emitting layer formed by the wet coating method using the composition for an organic electroluminescent device of the present invention, a light emitting material and a charge transporting material may be contained, and other light emitting materials and the charge transporting material will be described in detail below. ..
(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 material (blue fluorescent material) that gives blue light include naphthalene.
Examples thereof include perylene, pyrene, anthracene, coumarin, chrysene, p-bis (2-phenylethenyl) benzene and derivatives thereof.
Examples of the fluorescent light emitting material (green fluorescent light emitting material) that gives green light emission include a quinacridone derivative, a coumarin derivative, and an aluminum complex such as Al (C9H6NO) 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.
As a fluorescent light emitting material (red fluorescent light emitting material) that gives red light emission, for example, DCM (4-
(Dicyanomethyrene) -2-methyl-6- (p-dimethyrene)
Examples thereof include laminostyl) -4H-pyran) compounds, benzopyran derivatives, rhodamine derivatives, benzothioxanthene derivatives, and azabenzothioxanthene.

As the phosphorescent material, for example, from the 7th to 11th groups of the long periodic table (hereinafter, unless otherwise specified, the term "periodic table" refers to the long periodic table). Examples thereof include an organic metal complex containing a selected metal. The metal selected from Groups 7 to 11 of the periodic table is preferably 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-ethylhexyloxy) -1,4-phenylene vinylene] and other polyphenylene vinylene-based materials can be mentioned.

(Charge transport material)
The charge transporting material is a material having positive charge (hole) or negative charge (electron) transportability, and is not particularly limited as long as the effects of the present invention are not impaired, and known materials can be applied.
As the charge transporting material, a compound or the like conventionally used for the light emitting layer 5 of the organic electroluminescent device can be used, and a compound used as a host material for the light emitting layer 5 is particularly preferable.

Specific examples of the charge transporting material include aromatic amine compounds, phthalocyanine compounds, porphyrin compounds, oligothiophene compounds, polythiophene compounds, benzylphenyl compounds, and compounds in which a tertiary amine is linked with a fluorene group. , Hydrazone-based compounds, silazane-based compounds, silanamine-based compounds, phosphamine-based compounds, quinacridone-based compounds, and other compounds exemplified as hole-transporting compounds in the hole injection layer 3, as well as anthracene-based compounds and pyrene-based compounds. , Carbazole-based compounds, pyridine-based compounds, phenanthroline-based compounds, oxadiazole-based compounds, silol-based compounds and other electron-transporting compounds.

As the charge transporting material, 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. Aromatic diamine substituted with nitrogen atom (Japanese Patent Laid-Open No. 5-234681), 4, 4', 4''-
Aromatic amine compounds having a starburst structure such as tris (1-naphthylphenylamino) triphenylamine (J. Lumin., 72-74, pp. 985, 1997)
, Aromatic amine compound consisting of a tetramer of triphenylamine (Chem.Commun)
.. , 2175, 1996), 2,2', 7,7'-Tetrakis- (diphenylamino) -9,9'-Fluorene compounds such as spirobifluorene (Synth. Metals)
, 91, 209, 1997), compounds exemplified as hole-transporting compounds of the hole-transporting layer 4, such as carbazole-based compounds such as 4,4'-N, N'-dicarbazolebiphenyl, are also preferably used. be able to. In addition, 2- (4-biphenylyl) -5- (p-tershall butylphenyl) -1,3,4-oxadiazole (tBu-PBD), 2,5-bis (1-naphthyl) -1,3 , 4-Oxadiazole (BND) and other oxadiazole compounds, 2,5-bis (6'-(2', 2 "-bipyridyl))-1,1-dimethyl-3
, Siror compounds such as 4-diphenylsilol (PyPySPyPy), phenanthroline compounds such as vasofenanthroline (BPhen), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP, vasocproin), etc. Be done.

(Formation of light emitting layer 5 by wet film formation method)
The organic electroluminescent device of the present invention has a light emitting layer formed by wet coating using the composition for an organic electroluminescent device of the present invention.
As the light emitting layer 5, a light emitting layer may be provided in addition to the light emitting layer formed by wet coating using the composition for an organic electroluminescent device of the present invention. The light emitting layer may be formed by either a vacuum vapor deposition method or a wet film forming method, but the wet film forming method is preferable because of its excellent film forming property.

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 3 is formed by the wet film forming method, the light emitting layer is emitted instead of the composition for forming the hole injection layer. The material to be layer 5 is formed by mixing a soluble solvent (solvent for light emitting layer) with a light emitting layer forming composition prepared.
Examples of the solvent include ether-based solvents, ester-based solvents, aromatic hydrocarbon-based solvents, amide-based solvents, alcan-based solvents, halogenated aromatic hydrocarbon-based solvents, and fats, which were mentioned for the formation of the hole injection layer 3. Examples thereof include a group alcohol solvent, an alicyclic alcohol solvent, an aliphatic ketone solvent and an alicyclic ketone solvent. The solvent used is as exemplified as the solvent of the iridium complex compound-containing composition of the present invention. Specific examples of the solvent are given below, but the present invention is not limited thereto as long as the effect of the present invention is not impaired.

For example, aliphatic ether solvents such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether and propylene glycol-1-monomethyl ether acetate (PGMEA); 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetol, 2 Aromatic ether solvents such as −methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, diphenyl ether; phenyl acetate, phenyl propionate, methyl benzoate, benzoic acid Aromatic ester solvents such as ethyl, propyl benzoate, n-butyl benzoate; toluene, xylene, mesitylene, cyclohexylbenzene, tetralin, 3-isopropylbiphenyl, 1,2,3,4-tetramethylbenzene, 1,4 − Diisopropylbenzene,
Aromatic hydrocarbon solvents such as methylnaphthalene; N, N-dimethylformamide, N, N-
Amid solvents such as dimethylacetamide; Alcan solvents such as n-decane, cyclohexane, ethylcyclohexane, decalin, bicyclohexane; halogenated aromatic hydrocarbon solvents such as chlorobenzene, dichlorobenzene and trichlorobenzene; butanol, hexanol and the like. Alibo alcohol solvents; alicyclic alcohol solvents such as cyclohexanol and cyclooctanol; aliphatic ketone solvents such as methyl ethyl ketone and dibutyl ketone; alicyclic ketone solvents such as cyclohexanone, cyclooctanone and fencon. Be done. Of these, alkane-based solvents and aromatic hydrocarbon-based solvents are particularly preferable.

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, the boiling point of the solvent used is usually 80 ° C. or higher, preferably 1 as described above.
It is 00 ° C. or higher, more preferably 120 ° C. or higher, usually 270 ° C. or lower, preferably 250 ° C. or lower, and more preferably 230 ° C. or lower.
The amount of the solvent used is arbitrary as long as the effect of the present invention is not significantly impaired, but the total content in the light emitting layer forming composition, that is, the iridium complex compound-containing composition is low in viscosity, so that the film forming operation can be performed. A large amount is preferable in terms of ease of execution, and a low value is preferable in terms of easy film formation with a thick film. As described above, the content of the solvent is preferably 1% by mass in the iridium complex compound-containing composition.
As mentioned above, more preferably 10% by mass or more, particularly preferably 50% by mass or more, preferably 9
It is 9.99% by mass or less, more preferably 99.9% by mass or less, and particularly preferably 99% by mass or less.

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, but 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.
More preferably, it is 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 exceeding the above upper limit is higher than the heat resistance of a commonly used charge transport 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 5 by vacuum vapor deposition method)
When the light emitting layer 5 is formed by the vacuum vapor deposition method, usually one or more kinds of constituent materials of the light emitting layer 5 (the above-mentioned light emitting material, charge transporting compound, etc.) are installed in a crucible in a vacuum vessel. (When using two or more types of 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 heat the crucible (two or more types of materials). When using, usually heat each crucible) and evaporate while controlling the amount of evaporation of the material in the crucible (when using two or more types of materials, usually evaporate while controlling the amount of evaporation independently. Let)
, The light emitting layer 5 is formed on the hole injection layer 3 or the hole transport layer 4 placed facing the crucible. When two or more kinds of materials are used, a mixture thereof can be put in a crucible and heated and evaporated to form a 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 (12)
.. It is 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 during vapor deposition is
It is not limited as long as the effect of the present invention is not significantly impaired, but is preferably carried out at 10 ° C. or higher and 50 ° C. or lower.

<Hole blocking layer 6>
A hole blocking layer 6 may be provided between the light emitting layer 5 and the electron injection layer 8 described later. 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 (excitation triplet level).
T1) is high.

Examples of the material of the hole blocking layer 6 satisfying such conditions include bis (2-methyl-8).
-Kinolinolato) (Phenorato) Aluminum, Bis (2-Methyl-8-Kinolinolato)
(Triphenylsilanorat) Mixed ligand complex such as aluminum, bis (2-methyl-8-
Kinolato) Aluminum-μ-oxo-bis- (2-methyl-8-quinolinolato) Metal complexes such as aluminum dinuclear metal complexes, styryl compounds such as distyrylbiphenyl derivatives (Japanese Patent Laid-Open No. 11-2429996), 3- ( 4-biphenylyl) -4-phenyl-5 (4)
Triazole derivatives such as -tert-butylphenyl) -1,2,4-triazole (Japanese Patent Laid-Open No. 7-41759), phenanthroline derivatives such as vasocproin (Japanese Patent Laid-Open No. 10)
-79297) and the like. A compound having at least one pyridine ring substituted at the 2, 4 and 6 positions described in WO 2005/022962 is also preferable as a material for the hole blocking layer 6.

The method for forming the hole blocking layer 6 is not limited, and the hole blocking layer 6 can be formed in the same manner as the method for forming the light emitting layer 5 described above.
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.
It is 3 nm or more, preferably 0.5 nm or more, usually 100 nm or less, preferably 50 nm or less.

<Electronic transport layer 7>
The electron transport layer 7 is provided between the light emitting layer 5 or the hole element layer 6 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. As the electron-transporting compound used in the electron-transporting layer 7, the electron-injecting efficiency from the cathode 9 or the electron-injecting layer 8 is high, and the injected electrons can be efficiently transported with high electron mobility. It needs to be a compound.

Examples of the electron-transporting compound satisfying such conditions include a metal complex such as an aluminum complex of 8-hydroxyquinolin (Japanese Patent Laid-Open No. 59-194393), a metal complex of 10-hydroxybenzo [h] quinoline, and an oxa. Diazole derivative, distyrylbiphenyl derivative, silol derivative, 3-hydroxyflavon metal complex, 5-hydroxyflavon metal complex, benzoxazole metal complex, benzothiazole metal complex, trisbenzimidazolylbenzene (US Pat. No. 5,645,948), Kinoxalin compound (Japanese Patent Laid-Open No. 6)
−207169), Phenanthroline derivative (Japanese Patent Laid-Open No. 5-331459),
Examples thereof include 2-t-butyl-9,10-N, N'-dicyanoanthraquinone diimine, n-type hydrogenated amorphous silicon carbide, n-type zinc sulfide, and n-type zinc selenide.

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 a wet film deposition method or a vacuum vapor deposition method in the same manner as the light emitting layer 5.
Alternatively, it is formed by laminating on the hole blocking layer 6. Usually, a vacuum deposition method is used.

<Electronic injection layer 8>
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.

The film thickness of the electron injection layer 8 is preferably 0.1 to 5 nm.
LiF, MgF2, Li2O, as an electron injection layer 8 at the interface between the cathode 9 and the electron transport layer 7.
Inserting an ultra-thin insulating film (thickness of about 0.1 to 5 nm) such as Cs2CO3 is also an effective method for improving the efficiency of the device (Appl. Phys. Lett., Vol. 70, p. 152).
1997; JP-A-10-74586; IEEE Trans. Electron.
Devices, Vol. 44, p. 1245, 1997; SID 04 Digist, 15
Page 4).

Further, an organic electron transport material typified by a nitrogen-containing heterocyclic compound such as basophenanthroline or a metal complex such as an aluminum complex of 8-hydroxyquinoline is doped with an alkali metal such as sodium, potassium, cesium, lithium, or rubidium (). Japanese Patent Application Laid-Open No. 10-270
171), JP-A-2002-100478, JP-A-2002-1000482, etc.) is preferable because the electron injection / transportability is improved and excellent film quality can be achieved at the same time. In this case, the film thickness is usually 5 nm or more, preferably 10 nm or more, usually 200 nm or less, preferably 100 nm or less.

The electron injection layer 8 is formed by a wet film deposition method or a vacuum vapor deposition method in the same manner as the light emitting layer 5.
Alternatively, it is formed by laminating on the hole blocking layer 6 or the electron transporting layer 7 on the hole blocking layer 6.
The details of the wet film forming method are the same as those of the light emitting layer 5 described above.
<Cathode 9>
The cathode 9 plays a role of injecting electrons into a layer on the light emitting layer 5 side (electron injection layer 8, light emitting layer 5, etc.). As the material of the cathode 9, the material used for the anode 2 can be used, but in order to efficiently inject electrons, it is preferable to use a metal having a low work function.
For example, metals such as tin, magnesium, indium, calcium, aluminum and silver or alloys thereof are used. Examples of the material of the cathode 9 include alloy electrodes having a low work function such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy.

In terms of device stability, it is preferable to laminate a metal layer having a high work function and stable to the atmosphere on the cathode 9 to protect the cathode 9 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 is usually the same as that of the anode 2.

<Other constituent layers>
Although the elements having the layer structure shown in FIG. 1 have been mainly described above, the above description will be given as long as the performance between the anode 2 and the cathode 9 and the light emitting layer 5 in the organic electroluminescent device of the present invention is not impaired. In addition to the certain layer, any layer may be provided, or any layer other than the light emitting layer 5 may be omitted.

For example, it is also effective to provide an electron blocking layer between the hole transporting layer 4 and the light emitting layer 5 for the same purpose as the hole blocking layer 8. In the electron blocking layer, the electrons moving from the light emitting layer 5 are the hole transporting layer 4.
By preventing the holes from reaching, the probability of recombination with holes in the light emitting layer 5 is increased, the generated excitons are confined in the light emitting layer 5, and the holes injected from the hole transport layer 4 are trapped. Has a role of efficiently transporting the light in the direction of the light emitting layer 5.

The characteristics required for the electron blocking layer are high hole transportability and an energy gap (HO).
The difference between MO and LUMO) is large, and the excited triplet level (T1) is high.
When the light emitting layer 5 is formed by the wet film forming method, it is preferable to form the electron blocking layer by the wet film forming method because the device can be easily manufactured.
Therefore, it is preferable that the electron blocking layer also has wet film formation compatibility, and the material used for such an electron blocking layer is a copolymer of dioctylfluorene and triphenylamine represented by F8-TFB (international). Publication No. 2004/084260) and the like.

The structure opposite to that of FIG. 1, 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, the hole transport layer 4, the hole injection layer 3, and the anode on the substrate 1. It is also possible to stack in the order of 2. It is also possible to provide the organic electroluminescent device of the present invention between two substrates having at least one highly transparent substrate.
It is also possible to have a structure in which a plurality of layers shown in FIG. 1 are stacked (a structure in which a plurality of light emitting units are stacked). In that case, the interface layer between the stages (between the light emitting units) (anode is ITO, cathode is A)
If, for example, V2O5 or the like is used as the charge generation layer instead of the two layers in the case of l), the barrier between the stages is reduced, which is more preferable from the viewpoint of luminous efficiency and drive voltage.

The present invention can be applied to any of a single element, an element having an array-arranged structure, and a structure in which an anode and a cathode are arranged in an XY matrix.
[Display device and lighting device]
The display device and the lighting device of the present invention use the organic electroluminescent element of the present invention as described above. The type and structure of the display device and the lighting device of the present invention are not particularly limited, and can be assembled according to a conventional method using the organic electroluminescent element of the present invention.

For example, the display device and lighting device of the present invention by the method described in "Organic EL Display" (Ohmsha, published on August 20, 2004, by Shizushi Tokito, Chihaya Adachi, Hideyuki Murata). Can be formed.

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 carried out without departing from the gist thereof. All the reactions described in the synthesis examples were carried out under a nitrogen stream, and the solvent used in the reaction was degassed by an appropriate method such as nitrogen bubbling, if necessary.
<Synthesis Example 1: Synthesis of Compound 1>

12.28 g of 1-bromo-3-n-hexylbenzene in a 500 ml eggplant-shaped flask
, 3-N-carbazolephenylboronic acid 14.54 g, tetrakis (triphenylphosphine) palladium (0) 1.82 g, 2M-tripotassium phosphate aqueous solution 75 ml, toluene 100 ml and ethanol 50 ml, put in an oil bath at 105 ° C. At 105
The mixture was stirred while refluxing for minutes. After cooling to room temperature, the aqueous phase was removed, the solvent was removed under reduced pressure, and the obtained residue was purified by silica gel column chromatography (neutral silica gel, developing solvent: dichloromethane / hexane). As a result, 3- N-Carbazole-3'
20.79 g of -n-hexyl-1,1'-biphenyl was obtained.

In a 1L eggplant-shaped flask, 3-N-carbazol-3'-n-hexyl-1,1'-biphenyl 20.79 g, N-bromosuccinate imide 8.14 g, dichloromethane 720
After adding ml and stirring at room temperature for 2 hours, 1.5 ml of trifluoroacetic acid was added and the mixture was further stirred for 105 minutes. When the residue obtained after removing the solvent under reduced pressure was tried to be purified by silica gel column chromatography (reverse phase silica gel, developing solvent: acetonitrile / tetrahydrofuran), 22.22 g of Intermediate 1 was added as a pale yellowish green oily substance. Obtained. However, according to the liquid chromatograph analysis of this product, the purity of the LC surface 100 value was 90%, including the raw material and impurities presumed to be excessively brominated.

In a 1 L eggplant-shaped flask, 22.22 g of Intermediate 1 (LC purity 90%), 15.44 g of bis (pinacolat) diboron, 21.75 g of potassium acetate, [1,1'-bis (diphenylphosphino) ferrocene] palladium ( II) 1.08 g of dichloride dichloromethane adduct and 250 ml of dimethyl sulfoxide were added, and the mixture was stirred in an oil bath at 90 ° C. for 140 minutes. Then, 400 ml of water was added, the mixture was extracted twice with 150 ml of dichloromethane, washed with 150 ml of saturated brine, and 20 ml of magnesium sulfate was added in a bulk to dry. The residue obtained by filtering and removing the solvent under reduced pressure was purified by silica gel column chromatography (neutral silica gel, developing solvent: dichloromethane / hexane).
10.27 g of Intermediate 2 was obtained as a colorless amorphous substance.

2- (3-Bromophenyl) -5-phenylpyridine in a 300 ml eggplant-shaped flask
Add 3.84 g, intermediate 2 6.35 g, tetrakis (triphenylphosphine) palladium (0) 0.31 g, 2M-tripotassium phosphate aqueous solution 20 ml, toluene 40 ml and ethanol 25 ml, and in an oil bath at 105 ° C for 6 hours. The mixture was stirred while refluxing. After cooling to room temperature, the aqueous phase was removed, the solvent was removed under reduced pressure, and the obtained residue was purified by silica gel column chromatography (neutral silica gel, developing solvent: dichloromethane / hexane) to obtain a pale yellow amorphous substance. 6.37 g of Intermediate 3 was obtained. 2
-(3-Bromophenyl) -5-phenylpyridine has been published in Patent Publication 2014-423436.
It was synthesized by the method described in No. 0.

Intermediate 3 5.97 g, Tris (acetylacetonato) in a 100 ml eggplant-shaped flask
1.14 g of iridium (III) and 22.5 g of glycerin were added, and the oil bath was heated from room temperature to 230 ° C. and stirred for 6 hours. After cooling to room temperature, wash the residue with 50 ml of water and
After dissolving in 100 ml of dichloromethane, 10 ml of magnesium sulfate was added in a bulk and dried. After filtration, the solvent is removed and the obtained residue is subjected to silica gel column chromatography (
Purification with neutral silica gel (developing solvent: dichloromethane / hexane) gave 0.91 g of compound 1 as an orange solid. The maximum emission wavelength of Compound 1 was 566 nm.

<Synthesis Example 2: Synthesis of Compound 2>

In a 1L eggplant-shaped flask, 9.99 g of 2-chloro-5-iodopyridine, intermediate 4 1
8.06g, Tetrakis (triphenylphosphine) palladium (0) 1.20g, 2
50 ml of M-tripotassium phosphate aqueous solution, 100 ml of toluene and 40 of ethanol
ml was added, and the mixture was stirred while refluxing in an oil bath at 100 ° C. for 7 hours. After cooling to room temperature
The aqueous phase was removed, the solvent was removed under reduced pressure, and the obtained residue was purified by silica gel column chromatography (neutral silica gel, developing solvent: dichloromethane / hexane). As a result, Intermediate 5 was obtained as a pale yellow amorphous substance. I got .48g. The intermediate 4 was synthesized by the method of the intermediate (9) described in Japanese Patent Publication No. 2016/194784A1.

Intermediate 5 16.48 g, m-methoxyphenylboronic acid 8 in a 1 L eggplant-shaped flask
.. 80g, Tetrakis (Triphenylphosphine) Palladium (0) 2.01g, 2M
-Tripotassium phosphate aqueous solution 60 ml, toluene 100 ml and ethanol 50 m
1 was added, and the mixture was stirred while refluxing in an oil bath at 100 ° C. for 4 hours. After cooling to room temperature, the aqueous phase was removed, the solvent was removed under reduced pressure, and the obtained residue was purified by silica gel column chromatography (neutral silica gel, developing solvent: dichloromethane / hexane) to obtain a pale yellow amorphous substance. 18.28 g of intermediate 6 was obtained.

18.28 g of Intermediate 6 and 40 ml of dry dichloromethane were placed in a 1 L eggplant-shaped flask and immersed in an ice-water bath. Then 1M-boron tribromide dichloromethane solution 40 with stirring
ml was syringe injected over 15 minutes. After further stirring at room temperature for 2 hours, 25 ml of a 1M-boron tribromide dichloromethane solution was added, followed by stirring at room temperature for 1 hour. Then water
I tried separatory washing with 500 ml, but the oil phase was suspended, so 2M-tripotassium phosphate aqueous solution
200 ml and 1 L of ethyl acetate were added, the suspended oil phase was removed from the solvent under reduced pressure, ethyl acetate was further added to the obtained yellow residue to remove the separated aqueous phase, and the ethyl acetate phase was removed from the solvent under reduced pressure.

18.20 g of the obtained yellow residue was placed in a 1 L eggplant-shaped flask, and dried dichloromethane 2
After dissolving in 00 ml and 14 ml of triethylamine, 12 ml of trifluoromethanesulfonic anhydride was added at room temperature, and heat was generated. After stirring for 1.5 hours as it is, the mixture was separated and washed with 1 L of water, the oil phase was removed from the solvent under reduced pressure, and the obtained residue was purified by silica gel column chromatography (neutral silica gel, developing solvent: dichloromethane / hexane). However, 9.62 g of Intermediate 7 was obtained as a brown amorphous substance.

4. In a 1L eggplant-shaped flask, intermediate 7 9.62g, bis (pinacolato) diboron 4.
Add 12 g, 6.95 g potassium acetate, 0.43 g of [1,1'-bis (diphenylphosphino) ferrocene] palladium (II) dichloride dichloromethane adduct and 80 ml of dimethyl sulfoxide, and stir for 90 minutes in an oil bath at 90 ° C. did. After that, 1 L of water was added, the mixture was extracted with 300 ml of dichloromethane, the oil phase was removed under reduced pressure, and the obtained residue was purified by silica gel column chromatography (neutral silica gel, developing solvent: dichloromethane). Was obtained in an amount of 3.45 g.

8 3.45 g of intermediate, 2-bromo-9,9-dimethyl-10 in a 1 L eggplant-shaped flask
Add -phenyl-9,10-dihydroacridine (manufactured by Tokyo Kasei Co., Ltd.) 2.36 g, tetrakis (triphenylphosphine) palladium (0) 0.13 g, 10 ml of 2M-tripotassium phosphate aqueous solution, 20 ml of toluene and 10 ml of ethanol. The mixture was stirred while refluxing in an oil bath at 105 ° C. for 2 hours. After cooling to room temperature, the aqueous phase was removed, the solvent was removed under reduced pressure, and the obtained residue was purified by silica gel column chromatography (neutral silica gel, developing solvent: dichloromethane / ethyl acetate). As a result, a pale yellow amorphous substance was obtained. As a result, 1.03 g of intermediate 9 was obtained.

Intermediate 9 1.03 g, Tris (acetylacetonato) in a 100 ml eggplant-shaped flask
Add 0.15 g of iridium (III) and 1 ml of glycerin, and heat the oil bath at 180 ° C.
The temperature was raised from 1 to 235 ° C. over 7.5 hours, and the mixture was further stirred at 235 ° C. for 2.5 hours. After cooling to room temperature, the temperature was raised again and the mixture was stirred at 245 ° C. for 35 hours. After cooling to room temperature, the residue was washed with 10 ml of water, and the obtained residue was purified by silica gel column chromatography (neutral silica gel, developing solvent: dichloromethane / hexane) to obtain 0.42 g of compound 2 as a yellow-orange solid. It was. The maximum emission wavelength of Compound 2 was 560 nm.

<Element Example>
[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 130 nm (manufactured by Sanyo Vacuum Co., Ltd., sputter-deposited product) is 2 mm wide using ordinary photolithography technology and hydrochloric acid etching. An anode was formed by patterning the stripes of. 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 a composition for forming a hole injection layer, 3.0% by weight of a hole-transporting polymer compound having a repeating structure of the following formula (P1) and 0.3% by weight of an oxidizing agent (HI1) were added to ethyl benzoate. A composition dissolved in was prepared.

This solution was spin-coated on the substrate in the air, and the hot plate in the air was heated to 230 ° C.
It was dried in 30 minutes to form a uniform thin film having a film thickness of 42 nm, which was used as a hole injection layer.
Next, 100 parts by mass of the charge-transporting polymer compound having the following structural formula (HT-1) was dissolved in cyclohexylbenzene to prepare a 3.0 wt% solution.
This solution was spin-coated in a nitrogen glove box on a substrate coated with the hole injection layer and dried on a hot plate in the nitrogen glove box at 230 ° C. for 30 minutes to form a uniform thin film having a film thickness of 41 nm. It was formed and used as a hole transport layer.

Subsequently, as the material of the light emitting layer, the following structural formula (H-1) was used in an amount of 50 parts by mass, and the following structural formula (H-1) was used.
H-2) is 50 parts by mass, compound 1 is 17.1 mass, and the following structural formula (D-1) is 2.
Weighed 0 parts by weight and dissolved in cyclohexylbenzene to prepare a 8.0 wt% solution.

This solution was spin-coated in a nitrogen glove box on a substrate coated with the hole transport layer and dried on a hot plate in the nitrogen glove box at 120 ° C. for 20 minutes to form a uniform thin film having a film thickness of 80 nm. It was formed and used as a light emitting layer.
The substrate on which the light emitting layer was formed 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 following structural formula (HB-1) and 8-hydroxyquinolinola tritium were added 2: 3.
A hole blocking layer having a film thickness of 30 nm was formed by co-depositing on the light emitting layer at a rate of 1Å / sec by a vacuum vapor deposition method.

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 a cathode, aluminum is heated by a molybdenum boat, and the deposition rate is 1 to 8.
.. An aluminum layer having a film thickness of 80 nm was formed at 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.

[Example 2]
The light emitting layer composition is (H-1) :( H-2): Compound 2: (D-1) = 50: 50: 21 :.
An element was produced in the same manner as in Example 1 except that the value was 20. Compound 2 is contained in the light emitting layer in the same number of moles as compound 1 of Example 1. The maximum emission wavelength of D-1 is 605.
nm.

[Comparative Example 1]
The light emitting layer composition is (H-1) :( H-2) :( D-2) :( D-1) = 50: 50: 12
.. The device was manufactured in the same manner as in Example 1 except that the setting was 5:20. (D-2) is contained in the light emitting layer in the same number of moles as compound 1 in Example 1. The structural formula of (D-2) is shown below. The maximum emission wavelength of D-2 is 555 nm.

[Evaluation of element]
The obtained organic electroluminescent devices of Example 1, Example 2, and Comparative Example 1 have a brightness of 1000c.
The current efficiency (cd / A) when light was emitted at d / m ² was measured, and the relative value (relative current efficiency) when Comparative Example 1 was set to 100 is shown in Table 1 below. As shown in the results in Table 1, (D-2
), It was found that the efficiency of the organic electroluminescent device using the compound 1 or compound 2 of the present invention as the light emitting layer material is improved as compared with the organic electroluminescent device produced using the above.

[Example 3]
The composition of the light emitting layer is as follows: (H-1) :( H-2): Compound 1: (D-3) = 50: 50: 17.
The device was manufactured in the same manner as in Example 1 except that it was set to 1:20. The structural formula of (D-3) is shown below. The maximum emission wavelength of D-3 is 654 nm.

[Example 4]
The light emitting layer composition is (H-1) :( H-2): Compound 2: (D-3) = 50: 50: 21 :.
An element was produced in the same manner as in Example 1 except that the value was 20.
[Comparative Example 2]
The light emitting layer composition is (H-1) :( H-2) :( D-2) :( D-3) = 50: 50: 12
.. The device was manufactured in the same manner as in Example 1 except that the setting was 5:20.

[Evaluation of element]
The obtained organic electroluminescent devices of Example 3, Example 4, and Comparative Example 2 have a brightness of 1000c.
The current efficiency (cd / A) when light was emitted at d / m ² was measured, and the relative value (relative current efficiency) when Comparative Example 2 was set to 100 is shown in Table 2 below. As shown in the results in Table 1, (D-2
), It was found that the efficiency of the organic electroluminescent device using the compound 1 or compound 2 of the present invention as the light emitting layer material is improved as compared with the organic electroluminescent device produced using the above.

[Example 5]
The composition of the light emitting layer is as follows: (H-1) :( H-2): Compound 1: (D-4) = 50: 50: 17.
The device was manufactured in the same manner as in Example 1 except that it was set to 1:20. The structural formula of (D-4) is shown below. The maximum emission wavelength of D-4 is 635 nm.

[Comparative Example 3]
The light emitting layer composition is (H-1) :( H-2) :( D-2) :( D-4) = 50: 50: 12
.. The device was manufactured in the same manner as in Example 1 except that the setting was 5:20.
[Evaluation of element]
The current efficiency (cd / A) when the obtained organic electroluminescent devices of Example 5 and Comparative Example 3 were made to emit light at a brightness of 1000 cd / m ² was measured, and relative to the case where Comparative Example 2 was set to 100. The values are listed in Table 2 below. As shown in the results of Table 1, the organic electroluminescent device using the compound 1 of the present invention as the light emitting layer material has a comparison with the organic electroluminescent device manufactured by using (D-2).
It turned out to be more efficient.

_{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 electroluminescent device}

Claims (8)

Compounds represented by the following formula (1) and
A composition for an organic electroluminescent device containing a compound represented by the following formula (2), which has a longer maximum emission wavelength than the compound represented by the following formula (1), and a solvent.
[In the above formula, R ^{1 to} R ⁴ are independently alkyl groups having 1 to 20 carbon atoms and 7 carbon atoms, respectively.
~ 40 (hetero) aralkyl groups, 1 to 20 carbon alkoxy groups, 3 to 20 carbon atoms (
Hetero) aryloxy group, alkylsilyl group having 1 to 20 carbon atoms, 6 to 2 carbon atoms
Arylsilyl group with 0 carbon atoms, alkylcarbonyl group with 2 to 20 carbon atoms, arylcarbonyl group with 7 to 20 carbon atoms, alkylamino group with 1 to 20 carbon atoms, arylamino group with 6 to 20 carbon atoms, or carbon number of carbon atoms. Any of 3 to 30 (hetero) aryl groups, or a combination thereof. When having a plurality of substituents, they may be the same or different. These groups may further have a substituent.
a is an integer of 0 to 4, and b and c are integers of 0 to 3.
Ring A is a pyridine ring, a pyrazine ring, a pyrimidine ring, an imidazole ring, an oxazole ring,
It is any one of a thiazole ring, a quinoline ring, an isoquinoline ring, a quinazoline ring, a quinoxaline ring, an azatriphenylene ring, and a carboline ring.
Ring A may have a substituent, and the substituents are a fluorine atom, a chlorine atom, a bromine atom, an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, and a carbon number of carbon atoms. 1-20
Alkoxy group, (hetero) aryloxy group having 3 to 20 carbon atoms, alkylsilyl group having 1 to 20 carbon atoms, arylsilyl group having 6 to 20 carbon atoms, and 2 carbon atoms. Alkoxycarbonyl groups of ~ 20, arylcarbonyl groups of 7-20 carbon atoms,
It is either 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, or a combination thereof. Also,
Adjacent substituents bonded to ring A may be bonded to each other to further form a ring.
X ¹ represents a direct bond or CR ¹² R ¹³ .
Independently, R ¹² and R ¹³ have a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, and 3 to 20 carbon atoms.
(Hetero) aryloxy group, alkylsilyl group having 1 to 20 carbon atoms, 6 carbon atoms
Arylsilyl group having ~ 20 carbonyl group, alkylcarbonyl group having 2 to 20 carbon atoms, 7 to 2 carbon atoms
Represents an arylcarbonyl group of 0, an alkylamino group of 1 to 20 carbon atoms, an arylamino group of 6 to 20 carbon atoms, or a (hetero) aryl group of 3 to 30 carbon atoms, but these groups further comprise a substituent. You may have.
L ¹ represents an auxiliary ligand, and m is an integer of 1 to 3. When there are a plurality of co-ligands, they may be different or the same. ]
[In formula (2), R ⁵ is an alkyl group having 1 to 20 carbon atoms and 7 to 4 carbon atoms, respectively.
A (hetero) aralkyl group of 0, 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, and 6 to 20 carbon atoms. Arylsilyl group, alkylcarbonyl group with 2 to 20 carbon atoms, arylcarbonyl group with 7 to 20 carbon atoms, alkylamino group with 1 to 20 carbon atoms, arylamino group with 6 to 20 carbon atoms, or 3 to 30 carbon atoms Any (hetero) aryl group of, or a combination thereof. These groups may further have a substituent.
d is an integer from 0 to 4.
Ring B is a pyridine ring, a pyrazine ring, a pyrimidine ring, an imidazole ring, an oxazole ring,
It is any one of a thiazole ring, a quinoline ring, an isoquinoline ring, a quinazoline ring, a quinoxaline ring, an azatriphenylene ring, and a carboline ring.
Ring B may have a substituent, and the substituents are a fluorine atom, a chlorine atom, a bromine atom, an alkyl group having 1 to 20 carbon atoms, a (hetero) aralkyl group having 7 to 40 carbon atoms, and a carbon number of carbon atoms. 1-20
Alkoxy group, (hetero) aryloxy group having 3 to 20 carbon atoms, alkylsilyl group having 1 to 20 carbon atoms, arylsilyl group having 6 to 20 carbon atoms, and 2 carbon atoms. Alkoxycarbonyl groups of ~ 20, arylcarbonyl groups of 7-20 carbon atoms,
It is either 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, or a combination thereof. When having a plurality of substituents, they may be the same or different. Further, adjacent substituents bonded to the ring A may be bonded to each other to further form a ring.
L ² represents an auxiliary ligand, and n is an integer of 1 to 3. When there are a plurality of co-ligands, they may be different or the same. ] The composition for an organic electroluminescent device according to claim 1, wherein the formula (1) contains a compound represented by the formula (1-1).
[In the formula (1-1), R ^{1 to} R ⁴ , a, b, c, rings A, L ¹ , and m are R ¹ in the formula (1).
It is synonymous with ~ R ⁴ , a, b, c, rings A, L ¹ , m. ] The composition for an organic electroluminescent device according to claim 2, wherein the formula (1-1) contains a compound represented by the formula (1-2).
[In the above formula (1-2), R ^{1 to} R ⁴ , a, b, c, rings A, L ¹ , m are R ^{1 to} R ⁴ , a, b, c, in the formula (1-1). It is synonymous with rings A, L ¹ , and m. ] The composition for an organic electroluminescent device according to any one of claims 1 to 3, wherein m in the formula (1) is 3. The invention according to any one of claims 1 to 3, wherein m in the formula (1) is less than 3, and L ¹ has at least one of the formulas (3), (4), and (5). Composition for organic electroluminescent device.
[In the above formulas (3), (4) and (5), R ⁶ and R ⁷ are synonymous with the above R ^{1 to} R ⁴ . ] An organic electroluminescent device having a light emitting layer formed by using the organic electroluminescent device composition according to any one of claims 1 to 5. A display device having the organic electroluminescent element according to claim 6. A lighting device having the organic electroluminescent element according to claim 7.