JP2002134277A - Material for electroluminescence and electroluminescence element, and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a material for electroluminescence, which can obtain an electroluminescence element, which has high luminescence efficiency and outstanding durability, and can form an organic material layer certainly according to an easy process, and to provide the electroluminescence element, which has an electric charge transporting layer obtained from the material, and its manufacturing method. SOLUTION: The material for electroluminescence consists of a unit (AC), which has hole transporting nature structure units of 80 to 100 mol%, and bridge constructing nature structure units of 0n to 20 mol%, and a unit (ABC), which has hole transporting nature structure units of 40 to 60 mol%, electron transporting nature structure units of 40 to 60 mol%, and bridge constructing nature structure units of 0 to 20 mol%. A rate of the sum total of the hole transporting nature structure units and the electron transporting nature structure units of the unit (ABC), and the hole transporting nature structure units of the unit (AC) is 50:50 to 5:95 in mol ratio, and a rate of the bridge constructing nature structure units to all the structure units is 0.1 to 30 mol%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroluminescent material suitable for producing an electroluminescent device by a wet method, an electroluminescent device having a charge transport layer obtained from the electroluminescent material, and a method for producing the same. About.

[0002]

2. Description of the Related Art In recent years, organic materials have begun to be used as charge transporting materials such as hole transporting materials and electron transporting materials, and light emitting materials, which constitute electroluminescent devices. Organic electroluminescence using such organic materials has been started. Research on devices is being actively conducted. An organic material constituting such an organic electroluminescence element is required to have excellent durability and to obtain high luminous efficiency.

[0003] Conventionally, organic materials having hole transport performance include diamine derivatives, N, N'-diphenyl-N,
Low molecular weight organic materials such as arylamine compounds such as N'-di (3-methylphenyl) -4,4'-diaminobiphenyl and high molecular weight organic materials such as polyvinylcarbazole are known. However, since the low-molecular-weight organic material has poor physical or thermal durability, when the hole-transporting layer is formed of the low-molecular-weight organic material, the low-molecular-weight organic material is used during driving or storage of the electroluminescent element. In addition, there is a disadvantage that the hole transport layer is deteriorated. Further, since a high molecular weight organic material such as polyvinyl carbazole has a very high glass transition point (Tg), a hole transporting layer having excellent durability can be obtained. However, the driving voltage is very high. Since the hole transport performance is not sufficient, the luminous efficiency is low, and there is a practical problem. On the other hand, as the electron transporting material, 2- (4-biphenylyl) -5- (4-tert-butylphenyl)-
Although 1,3,4-oxadiazole (hereinafter, also referred to as “PBD”) is known, there is a problem that a thin film made of this PBD lacks stability.

[0004] Further, when an electroluminescent element is formed from the above-mentioned conventional organic materials, there are the following problems. As a method of forming an organic material layer in an electroluminescent element, a dry method in which an organic material layer is formed by vacuum-depositing an organic material, and a method in which a solution in which an organic material is dissolved is applied and dried by applying Wet processes are known for forming. Among them, in the dry method, the steps are complicated and it is difficult to cope with mass production, and there is a limit in forming a layer having a large area. On the contrary,
The wet method is advantageous in comparison with the dry method in that the process is simple and can cope with mass production, and an organic material layer having a large area can be easily formed. When a plurality of organic material layers, for example, a charge transport layer and a light emitting layer are formed by such a wet method, the charge transport material is dissolved on the surface of the substrate on which the charge transport layer is to be formed. A charge transport layer forming solution is applied and dried to form a charge transport layer, and then, on the surface of the charge transport layer, a light emitting material forming solution formed by dissolving a light emitting material is applied and dried. A light emitting layer is formed. However, in forming the light emitting layer, when the light emitting layer forming solution is applied to the surface of the charge transporting layer, the charge transporting layer is dissolved in the light emitting layer forming solution, and further, the charge transporting material is coated with the light emitting layer forming solution. Therefore, it is difficult to form an intended light emitting layer without damaging the charge transport layer.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a first object of the present invention is to provide an electroluminescent device having high luminous efficiency and excellent durability. An object of the present invention is to provide an electroluminescent material which can be obtained and can form an organic material layer reliably by a simple process. A second object of the present invention is to provide an electroluminescent element having high luminous efficiency, excellent durability, and capable of reliably forming an organic material layer by a simple process. A third object of the present invention is to provide an electroluminescent device which can produce an electroluminescent device having high luminous efficiency and excellent durability, and which can surely form an organic material layer by a simple process. It is to provide a manufacturing method of.

[0006]

The electroluminescent material of the present invention comprises 80 to 100 mol% of a structural unit derived from a monofunctional hole transporting monomer and 0 to 20 mol% of a structural unit derived from a polyfunctional crosslinking monomer. (AC), a structural unit derived from a monofunctional hole transporting monomer, 40 to 60 mol%, a structural unit derived from a monofunctional electron transporting monomer, 40 to 60 mol%, and a polyfunctional crosslinking monomer. A unit (ABC) composed of 0 to 20 mol% of structural units,
The ratio of the sum of the structural units derived from the monofunctional hole transporting monomer and the structural units derived from the monofunctional electron transporting monomer in BC) to the structural unit derived from the monofunctional hole transporting monomer in the unit (AC) But,
The molar ratio is 50:50 to 5:95, and the ratio of the structural unit derived from the polyfunctional crosslinking monomer in all the structural units constituting the unit (AC) and the unit (ABC) is 0.1. -10 mol%.

In the electroluminescent material of the present invention, the unit (ABC) is the same as the structural unit derived from a monofunctional hole transporting monomer except for the structural unit derived from a polyfunctional crosslinking monomer. The structural units derived from the monomer are alternately present, and the structural unit derived from the polyfunctional crosslinkable monomer is the unit (A
It is preferable that they exist in a dispersed state in (BC).

[0008] The electroluminescent material of the present invention may be a block copolymer composed of a block component composed of the unit (AC) and a block component composed of the unit (ABC). Further, the electroluminescent material of the present invention comprises a copolymer comprising the unit (AC) and the unit (ABC)
And a resin composition comprising a copolymer comprising Further, the electroluminescence material of the present invention comprises a block copolymer composed of a block component composed of the unit (AC) and a block component composed of the unit (ABC), and a copolymer composed of the unit (AC). And a copolymer comprising the above-mentioned unit (ABC).

The electroluminescent device of the present invention is characterized by having at least an anode layer, a charge transport layer obtained from the above-described electroluminescent material, a light emitting layer, and a cathode layer.

In the method for producing an electroluminescent device according to the present invention, a charge transport layer forming solution obtained by dissolving the above electroluminescent material in an organic solvent is applied to the surface of a substrate on which a charge transport layer is to be formed. Forming a charge transport layer by heat treatment, forming a light emitting layer by applying a light emitting layer forming solution in which a light emitting material is dissolved in an organic solvent to the surface of the charge transport layer and performing heat treatment. Characterized by a step of performing

[0011]

Embodiments of the present invention will be described below in detail. [Electroluminescent Material] The electroluminescent material of the present invention comprises 80 to 100 mol% of a structural unit derived from a monofunctional hole transporting monomer (hereinafter also referred to as “hole transporting structural unit”) and a polyfunctional crosslinkable material. A unit (A) comprising 0 to 20 mol% of a structural unit derived from a monomer (hereinafter, also referred to as a “crosslinkable structural unit”)
C), 40 to 60 mol% of a hole transporting structural unit, 40 to 60 mol% of a structural unit derived from a monofunctional electron transporting monomer (hereinafter, also referred to as “electron transporting structural unit”), and a crosslinkable structural unit. Unit consisting of 0 to 20 mol% (A
BC).

The monofunctional hole transporting monomers include N
Using carbazole derivatives such as -vinylcarbazole, 3,6-dimethyl-9-vinylcarbazole, 3,6-diethyl-9-vinylcarbazole, 3-methyl-9-vinylcarbazole and 3-ethyl-9-vinylcarbazole Can be. Among these, N-vinylcarbazole and 3,6-dimethyl-9-vinylcarbazole are preferred.

The monofunctional electron transporting monomers include 2-
β-naphthyl-5- (4-vinylphenyl) -1,3,3
4-oxadiazole, 2-α-naphthyl-5- (4-
Vinylphenyl) -1,3,4-oxadiazole, 2
Oxadiazole derivatives such as -phenyl-5- (4-vinylphenyl) -oxadiazole and 2- (p-phenylphenyl) -5- (4-vinylphenyl) -oxadiazole can be used. Among them, 2-
β-naphthyl-5- (4-vinylphenyl) -1,3,3
4-oxadiazole is preferred.

The polyfunctional crosslinkable monomer has two or more reactive functional groups in one molecule, and at least one functional group is a monofunctional hole transporting monomer or a monofunctional electron transporting monomer. Those that can be copolymerized with are used. Examples of the reactive functional group include a group having an ethylenically unsaturated double bond such as a vinyl group and an isopropenyl group (hereinafter, also referred to as a “double bond-containing group”), an epoxy group, an isocyanate group, and a carboxyl group. A hydroxy group, and the like. Examples of the polyfunctional crosslinking monomer include those having two or more double bond-containing groups, those having a double bond-containing group and an epoxy group, those having a double bond-containing group and an isocyanate group. And those having a double bond-containing group and a carboxyl group (including an anhydride), those having a double bond-containing group and a hydroxy group, and the like.

Specific examples of the monomer having two or more double bond-containing groups include divinyl ether, trimethylolpropane triacrylate, divinylbenzene and the like. Specific examples of the monomer having a double bond-containing group and an epoxy group include glycidyl acrylate,
Glycidyl methacrylate and the like can be mentioned. Specific examples of the monomer having a double bond-containing group and an isocyanate group include ethoxy methacrylate isocyanate. Specific examples of the monomer having a double bond-containing group and a carboxyl group include maleic anhydride. Specific examples of the monomer having a double bond-containing group and a hydroxy group include 2-hydroxyethyl acrylate.

In the electroluminescent material of the present invention, the ratio of the total of the hole transporting structural unit and the electron transporting structural unit in the unit (ABC) to the ratio of the hole transporting structural unit in the unit (AC) is mol. In a ratio of 50:50 to 5:95, preferably 40:50.
60 to 10:90. When the proportion of the hole transporting structural unit and the electron transporting structural unit in the unit (ABC) is too small, the obtained electroluminescent material has insufficient hole trapping performance. On the other hand, when the proportion of the hole transporting structural unit in the unit (AC) is too small, the obtained electroluminescent material has insufficient electron trapping performance, which is not preferable.

In the unit (ABC), except for the crosslinkable structural unit, the hole transportable structural unit and the electron transportable structural unit are alternately present, and the crosslinkable structural unit is contained in the unit (ABC). Preferably, it exists in a dispersed state.

In the electroluminescent material of the present invention, the proportion of the crosslinkable structural unit in all the structural units in the unit (AC) and the unit (ABC) is 0.1 to 10 mol%, preferably 0.1 to 10 mol%. It is 5 to 5 mol%. If the proportion of the crosslinkable structural unit is too small, the charge transport layer obtained by the electroluminescent material has low organic solvent resistance,
The wet method makes it difficult to form a light emitting layer on the surface of the charge transport layer without damaging the charge transport layer. On the other hand, when the proportion of the crosslinkable structural unit is too large, gelation or the like occurs during production, or the coating film formed due to an excessive crosslink density tends to be brittle, and furthermore, electroluminescence Characteristics may be significantly reduced. In the electroluminescent material of the present invention, when the proportion of the crosslinkable structural unit satisfies the above range, the crosslinked structural unit is contained only in the unit (AC), but is contained only in the unit (ABC). Or may be contained in both of them.

In the present invention, the unit (ABC) and the unit (AC) may be present in any state, for example, as a block component constituting a block copolymer or as a copolymer itself. Good. Specifically, the electroluminescent material of the present invention can be constituted by the following first to third embodiments.

First embodiment: a block component obtained by copolymerizing a monofunctional hole transporting monomer, a monofunctional electron transporting monomer and a polyfunctional crosslinking monomer [unit (AB)
C)] and a block component [unit (AC)] obtained by copolymerizing a monofunctional hole transporting monomer and a polyfunctional crosslinking monomer. Second Embodiment: Monofunctional Hole Transport [Unit (ABC)] obtained by copolymerizing a functional monomer, a monofunctional electron transporting monomer and a polyfunctional crosslinking monomer with a monofunctional hole transporting monomer and a polyfunctional crosslinking monomer A resin composition comprising a copolymer [unit (AC)], a third embodiment: a block component obtained by copolymerizing a monofunctional hole transporting monomer, a monofunctional electron transporting monomer, and a polyfunctional crosslinking monomer [ Unit (ABC)] and a block component [unit (AC)] obtained by copolymerizing a monofunctional hole transporting monomer and a polyfunctional crosslinking monomer. A block copolymer, a monofunctional hole-transporting monomer, monofunctional electron transporting monomer and a multifunctional crosslinking monomer is copolymerized copolymer [unit (AB
C)] and a copolymer [unit (AC)] obtained by copolymerizing a monofunctional hole transporting monomer and a polyfunctional crosslinking monomer.

[First Embodiment] The electroluminescent material according to the first embodiment comprises a block component (hereinafter referred to as a block component) obtained by copolymerizing a monofunctional hole transporting monomer, a monofunctional electron transporting monomer and a polyfunctional crosslinking monomer. ,
Also referred to as “block component (abc)”. ) And a block component obtained by copolymerizing a monofunctional hole transporting monomer and a polyfunctional crosslinking monomer (hereinafter referred to as “block component (a
c) ". )), And the block component (abc) is a hole transporting structural unit except for a crosslinkable structural unit. And the electron-transporting structural unit are alternately present, and the crosslinkable structural unit is preferably present in a dispersed state in the block component (abc).

The weight average polymerization degree of the block component (abc) in the specific block copolymer is preferably from 5 to 5,000. When the weight average degree of polymerization is less than 5, the obtained electroluminescent material tends to have insufficient heat resistance and stability.
When the weight average degree of polymerization exceeds 5,000, the resulting material for electroluminescence tends to have a remarkably high solution viscosity.

The weight average degree of polymerization of the block component (ac) in the specific block copolymer is from 10 to 500.
It is preferably 0. When the weight average degree of polymerization is less than 10, the obtained electroluminescent material tends to have insufficient heat resistance, stability and mechanical strength. On the other hand, when the weight average degree of polymerization exceeds 5,000 In the meantime, the obtained electroluminescent material tends to have a remarkably high solution viscosity.

The weight average molecular weight of the specific block copolymer is, for example, from 1,000 to 100,000 in terms of polystyrene by gel permeation chromatography.
0, preferably 10,000 to 500,000. When the weight average molecular weight is less than 1000, the obtained electroluminescent material may have insufficient heat resistance, stability in a thin film state, and mechanical strength. On the other hand, when the weight average molecular weight is 10,000
When it exceeds 00, the obtained material for electroluminescence tends to have a remarkably high solution viscosity, and in the production of an electroluminescence device,
It is not preferable because the handleability is lowered and the solution is liable to string.

The above-mentioned specific block copolymer is preferably a monofunctional hole-transporting monomer, a monofunctional electron-transporting monomer under the condition that the monofunctional hole-transporting monomer and the monofunctional electron-transporting monomer can be alternately copolymerized. A living polymer forming a block component (abc) is prepared by copolymerizing a functional monomer and a polyfunctional crosslinkable monomer, and a monofunctional hole transporting monomer and a polyfunctional crosslinkable monomer are copolymerized with the living polymer. To form a block component (ac). As such a living polymerization method, it is preferable to use a living cationic polymerization method or a living radical polymerization method.

When a specific block copolymer is obtained by the living cationic polymerization method, for example, in a suitable polymerization solvent, cationic polymerization capable of alternately copolymerizing a monofunctional hole transporting monomer and a monofunctional electron transporting monomer is used. In the presence of a catalyst, a monofunctional hole transporting monomer, a monofunctional electron transporting monomer, and a polyfunctional crosslinking monomer are cationically polymerized to remove the crosslinkable structural unit, thereby excluding the hole transporting structural unit and the electron transporting structural unit. Are alternately present, and a cross-linkable structural unit is dispersed in the polymer to form a cationic living polymer, and a monofunctional hole transporting monomer and a polyfunctional cross-linking monomer are added to the cationic living polymer. Cationic polymerization.

In the above, as the polymerization solvent, halogenated hydrocarbons represented by methylene chloride, chlorobenzene and the like, ether solvents such as dibutyl ether, diphenyl ether, dioxane and tetrahydrofuran, and highly polar solvents such as acetonitrile and nitrobenzene, etc. Can be used. As the cationic polymerization catalyst,
A catalyst such as HI-ZnI ₂ , I ₂ , I ₂ -HI can be used, and a catalyst obtained by combining a Lewis acid such as a metal halide ether complex with a base can also be used. The proportion of such a cationic polymerization catalyst used is a monofunctional hole transporting monomer to be polymerized first,
The amount is 0.0001 to 0.5 mol per 1 mol of the total of the monofunctional electron transporting monomer and the polyfunctional crosslinking monomer. The reaction temperature is, for example, -150 to 50 ° C. Further, the monofunctional hole transporting monomer and the polyfunctional crosslinking monomer for forming the block component (ac) may be added to the reaction system after forming the cationic living polymer [block component (abc)]. May be added to the reaction system before forming the cationic living polymer.

When a specific block copolymer is obtained by living radical polymerization, a radical polymerization catalyst capable of alternately copolymerizing a monofunctional hole transporting monomer and a monofunctional electron transporting monomer in an appropriate polymerization solvent. In the presence of, by radical polymerization of a monofunctional hole transporting monomer, a monofunctional electron transporting monomer and a polyfunctional crosslinking monomer, when the crosslinking structural unit is removed,
The hole-transporting structural units and the electron-transporting structural units are basically alternately bonded to form a radical living polymer in which crosslinkable structural units are dispersed in a polymer. Radical polymerizes a monofunctional hole transporting monomer and a polyfunctional crosslinking monomer.

In the above, polymerization solvents include amide solvents such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone, hydrocarbon solvents such as benzene, toluene, xylene, hexane and cyclohexane, γ-butyrolactone, ethyl lactate and the like. Esters,
Ketone solvents such as cyclohexylbenzophenone and cyclohexanone can be used. As the radical polymerization catalyst, peroxide, 4-methylsulfonyloxy-2,2 ', 6,6'-tetramethyl-1-piperidine-N-oxide, 2,2', 5,5'-tetramethyl Pyrrolideine oxide, 4-oxo-2,2 ', 6
A sulfide-based catalyst or a system comprising a combination with an N-oxy radical such as 6'-tetramethyl-1-piperidine-N-oxide can be used. In addition, azobisisobutyronitrile and the like can be used. The usage ratio of such a radical polymerization catalyst is 0.0001 to 0.5 mol per 1 mol of the monomer. The reaction temperature is determined by the energy required for the end-protected living group to be cleaved, for example, from room temperature to 200 ° C. Further, the monofunctional hole transporting monomer and the monofunctional crosslinking monomer for forming the block component (ac) are a radical living polymer [block component (ab
c)] may be added to the reaction system after the formation, or may be added to the reaction system before forming the radical living polymer.

[Second Aspect] The electroluminescent material according to the second aspect is a copolymer obtained by copolymerizing a monofunctional hole transporting monomer, a monofunctional electron transporting monomer and a polyfunctional crosslinking monomer. Hereinafter, also referred to as “copolymer (abc)”) and a copolymer obtained by copolymerizing a monofunctional hole transporting monomer and a polyfunctional crosslinking monomer (hereinafter, also referred to as “copolymer (ac)”). .)
And a copolymer (ab
c) Except for the crosslinkable structural unit, the hole transportable structural unit and the electron transportable structural unit are present alternately, and the crosslinkable structural unit is present in a dispersed state in the copolymer (abc). It is preferred that

<Copolymer (abc)> Copolymer (abc)
c) preferably comprises converting the monofunctional hole-transporting monomer, the monofunctional electron-transporting monomer and the polyfunctional crosslinkable monomer under conditions in which the monofunctional hole-transporting monomer and the monofunctional electron-transporting monomer can be copolymerized alternately. It is obtained by copolymerization. The weight average molecular weight of the copolymer (abc) is, for example, 1150 to 1,000,000 in terms of polystyrene by gel permeation chromatography,
In particular, it is preferably 11500 to 500000.
When the weight average molecular weight is less than 1150, the obtained electroluminescent material may have insufficient heat resistance, stability in a thin film state, and mechanical strength. On the other hand, when the weight average molecular weight is 100
If it exceeds 0000, the resulting electroluminescent material is likely to have a remarkably high solution viscosity, and in the production of the electroluminescent element, the handling property is reduced and the stringiness of the solution is generated. Absent.

As a method of copolymerizing a monofunctional hole transporting monomer, a monofunctional electron transporting monomer and a polyfunctional crosslinking monomer, a method in which a monofunctional hole transporting monomer and a monofunctional electron transporting monomer can be alternately copolymerized. It is preferable that, if such a method, various methods such as a radical polymerization method, an anion polymerization method or a cationic polymerization method,
Preferably their corresponding living radical polymerization methods,
A living anionic polymerization method or a living cationic polymerization method can be used.

The copolymer (ab) is prepared by a radical polymerization method.
In the case of obtaining c), the radical polymerization catalyst includes
Peroxides such as benzoyl peroxide and t-butyl hydroperoxide, and azo compounds such as 1,1′-azobis (1-acetoxy-1-phenylethane), azobisisobutyronitrile, and azobisisobutyrate Can be used. Among these, 1,1′-azobis (1-acetoxy-1-phenylethane) and azobisisobutyronitrile are preferred. The usage ratio of such a radical polymerization catalyst is 0.0
001 to 0.5 mol. Also, as the polymerization solvent,
Amide solvents such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone; hydrocarbon solvents such as benzene, toluene, xylene, hexane and cyclohexane; esters such as γ-butyrolactone and ethyl lactate; ketones such as cyclohexylbenzophenone and cyclohexanone A system solvent and cyclic ethers such as tetrahydrofuran can be used. The reaction temperature is
For example, it is 0 to 100 ° C.

The copolymer (ab) is prepared by anionic polymerization.
In the case of obtaining c), the anionic polymerization catalyst includes:
Alkaline metal compounds such as potassium naphthalene and butyl lithium, and alkaline earth metal compounds such as art-type complexes of barium and aluminum can be used. Of these, butyl lithium and naphthalene lithium are preferred. The use ratio of such an anionic polymerization catalyst is 0.0001 to 0.1 mol per 1 mol of the monomer. As the polymerization solvent, aromatic hydrocarbons such as toluene and benzene, aliphatic hydrocarbons such as hexane and heptane, and ether compounds such as tetrahydrofuran can be used. The reaction temperature is, for example, 0 to 100.
° C.

The copolymer (ab) is prepared by a cationic polymerization method.
In the case of obtaining c), the cationic polymerization catalyst includes:
An ether complex of boron fluoride, a halogen such as hydrogen iodide, or a metal halide such as tin tetrachloride can be used. Among these, boron fluoride ethyl ether complex, hydrogen iodide, and tin tetrachloride are preferable. The use ratio of such a cationic polymerization catalyst is 0.0001 to 0.1 mol per 1 mol of the monomer. As the polymerization solvent, halogenated hydrocarbons represented by methylene chloride, chlorobenzene and the like, cyclic ethers such as dibutyl ether, diphenyl ether, dioxane, tetrahydrofuran and the like, highly polar solvents such as acetonitrile, nitrobenzene and the like can be used. . The reaction temperature is, for example, -150 to 50 ° C.

<Copolymer (ac)> Copolymer (ac)
Is obtained by copolymerizing a monofunctional hole transporting monomer and a polyfunctional crosslinking monomer. The weight average molecular weight of this copolymer (ac) is, for example, 100 in terms of polystyrene by gel permeation chromatography.
It is preferably from 0 to 1,000,000, particularly preferably from 5,000 to 500,000. When the weight average molecular weight is less than 1000, the obtained electroluminescent material may have insufficient heat resistance, stability in a thin film state, and mechanical strength. On the other hand, when the weight average molecular weight exceeds 1,000,000, the resulting electroluminescent material tends to have a remarkably high solution viscosity, and in the production of the electroluminescent element, the handling property is reduced, and the solution yarn It is not preferable because it causes pulling.

Various methods can be used for copolymerizing the monofunctional hole transporting monomer and the polyfunctional crosslinking monomer, for example, a radical polymerization method, an anionic polymerization method or a cationic polymerization method, preferably their corresponding living radical polymerization methods, A living anionic polymerization method or a living cationic polymerization method can be used.

Copolymer (ac) by radical polymerization
In the case where is obtained, as the radical polymerization catalyst, an azo compound such as azobisisobutyronitrile (AIBN);
Known compounds such as peroxides such as benzoyl peroxide (BPO) and dithiocarbamate derivatives such as tetraethylthiuram disulfide can be used. In particular, 2,
Living radical polymerization is preferably performed by a catalyst system in which an N-oxy radical such as 2,6,6-tetramethyl-1-piperidine-N-oxide (TEMPO) is combined with a radical initiator. The usage ratio of such a radical polymerization catalyst is 0.0001 to 0.5 mol per 1 mol of the monomer. As the polymerization solvent, dimethylformamide, dimethylacetamide,
Amide solvents such as N-methylpyrrolidone, benzene,
Hydrocarbon solvents such as toluene, xylene, hexane and cyclohexane, esters such as γ-butyrolactone and ethyl lactate, ketone solvents such as cyclohexylbenzophenone and cyclohexanone, and cyclic ethers such as tetrahydrofuran can be used. The reaction temperature is, for example, -10 to 150C.

Copolymer (ac) by anionic polymerization
In the case of obtaining an anion polymerization catalyst, an alkali metal, an organometallic compound of a metal such as an alkaline earth metal is used, for example, an olefin catalyst such as naphthyl sodium, an alkyl lithium such as methyl lithium, ethyl lithium, butyl lithium, etc. And aryl complexes such as phenyllithium, alkyl zinc such as diethyl zinc, lithium alkyl magnesium, and art complexes such as lithium alkyl barium. Among these, n-butyllithium, sec-butyllithium,
Organolithium compounds such as phenyllithium are preferred.
As the polymerization solvent, hydrocarbons such as benzene, toluene, hexane, heptane, and cyclohexane, and ether compounds such as tetrahydrofuran and dioxane can be used. The reaction temperature is, for example, −50.
１００100 ° C.

Copolymer (ac) by cationic polymerization
In the case where is obtained, as the cationic polymerization catalyst, known catalysts such as Lewis acids such as trifluoroborate and tin tetrachloride, inorganic acids such as sulfuric acid and hydrochloric acid, and cation exchange resins can be used. In particular, it is preferable to perform living cationic polymerization using a catalyst such as HI or HI-ZnI ₂ . The use ratio of such a cationic polymerization catalyst is 0.0001 to 0.1 mol per 1 mol of the monomer. As the polymerization solvent, halogenated hydrocarbons represented by methylene chloride, chlorobenzene and the like, cyclic ethers such as dibutyl ether, diphenyl ether, dioxane, tetrahydrofuran and the like, highly polar solvents such as acetonitrile, nitrobenzene and the like can be used. .
The reaction temperature is, for example, -150 to 50 ° C.

The electroluminescent material in the second embodiment is obtained by mixing the above-mentioned copolymer (abc) and the above-mentioned copolymer (ac). The ratio of the copolymer (abc) to the copolymer (ac) is determined by the sum of the hole transporting structural unit and the electron transporting structural unit in the copolymer (abc) and the hole transporting property in the copolymer (ac). The ratio with the structural unit is 50:50 to 9 in a molar ratio.
The range is 5: 5, and the ratio of the crosslinkable structural unit to the total structural unit in the copolymer (abc) and the copolymer (ac) is 0.1 to 10 mol%. The copolymer (abc) is usually, but not particularly limited to, a copolymer (abc).
10 to 100 parts by weight of copolymer (ac) based on 100 parts by weight
0 parts by weight, preferably 100 to 800 parts by weight.

[Third Aspect] The electroluminescent material according to the third aspect is composed of a resin composition comprising a specific block copolymer, a copolymer (abc), and a copolymer (ac). And obtained by mixing the three. Specific block copolymers and copolymers (ab
The ratio of c) to the copolymer (ac) depends on the block component (abc) and the copolymer (ab) of the specific block copolymer.
c) the sum of the hole transporting structural units and the electron transporting structural units in each of the above, and the sum of the hole transporting structural units in each of the block component (ac) and the copolymer (ac) of the specific block copolymer. Is a molar ratio of 5
0:50 to 95: 5, and the ratio of the crosslinkable structural unit in all the structural units in the specific block copolymer, copolymer (abc) and copolymer (ac) is 0. It is not particularly limited as long as it is in the range of 0.1 to 10 mol%, but usually the copolymer (abc) is 10 to 1000 parts by weight, preferably 100 to 800 parts by weight, per 100 parts by weight of the specific block copolymer. Parts by weight, copolymer (a
c) is 50 to 1000 parts by weight, preferably 100 to 80 parts by weight
0 parts by weight.

According to the material for electroluminescence as described above, a unit having a hole transporting structural unit and a unit having an electron transporting structural unit (ABC) and a unit having a hole transporting structural unit (AC) are provided. A charge transporting layer in which hole transporting ability and electron transporting ability are efficiently expressed can be formed. As a result, an electroluminescent device having high luminous efficiency and high durability can be obtained. Further, since each of the unit (ABC) and the unit (AC) is a chain polymer component and is soluble in an organic solvent, a charge transport forming solution in which the electroluminescent material is dissolved is prepared. Thereby, the charge transport layer can be formed by a wet method. Moreover, since each of the unit (ABC) and the unit (AC) has a crosslinkable structural unit,
For example, a cross-linking reaction can be caused by heat treatment, whereby a charge transport layer made of a cross-linked polymer can be formed. Therefore, when the light emitting layer is formed by a wet method on the surface of the charge transporting layer obtained from the electroluminescent material of the present invention, the charge transporting layer does not dissolve in the light emitting layer forming solution.
The intended light emitting layer can be reliably formed without damaging the charge transport layer.

[Electroluminescence Element] The electroluminescence element of the present invention has at least an anode layer, a charge transport layer obtained from the above-described electroluminescence material, a light emitting layer, and a cathode layer. Hereinafter, a specific configuration example according to the electroluminescent element of the present invention will be described.

FIG. 1 is an explanatory cross-sectional view showing a first configuration example of the electroluminescent device of the present invention.
In this electroluminescent element, an anode layer (hole injection electrode layer) 2 is provided on a transparent substrate 1,
A charge transport layer 10 obtained from the above-described electroluminescent material is provided on the anode layer 2, and a light emitting layer 15 is provided on the charge transport layer 10. A layer (electron injection electrode layer) 3 is provided. The anode layer 2 and the cathode layer 3 are connected to a DC power source 5.
It is connected to the.

In the above, as the transparent substrate 1, a glass substrate, a transparent resin substrate, a quartz glass substrate or the like can be used. The anode layer 2 is made of a material having a large work function (for example, 4 eV or more), for example, ITO.
A film, a tin oxide (SnO ₂ ) film, a copper oxide (CuO) film, a zinc oxide (ZnO) film, or the like can be used. As a light-emitting material constituting the light-emitting layer 15, a metal complex of hydroxyquinoline represented by trisquinolinolate aluminum, a metal complex of hydroxybenzoxazole, a metal complex of hydroxybenzthiazole, or the like can be used. The cathode layer 3 has a small work function (for example, 4 e
V or less) A material made of a material, for example, a metal film made of aluminum, calcium, magnesium, lithium, indium, or the like, an alloy film of these metals, or an alloy film of these metals and another metal can be used. . The thickness of each of the charge transport layer 10 and the light emitting layer 15 is
Although not particularly limited, usually, 5 to 1000 n
m, preferably in the range of 15 to 200 nm.

Such an electroluminescent device can be manufactured, for example, as follows. First, an anode layer 2 is formed on the surface of a transparent substrate 1, and a charge transport layer forming solution obtained by dissolving the electroluminescent material of the present invention in an appropriate organic solvent is applied to the surface of the anode layer 2. By heating the obtained coating film, the organic solvent in the coating film is removed, and the polymer constituting the electroluminescent material undergoes a crosslinking reaction, whereby the charge transport layer 10 is formed. Is done.

In the above, as a method for forming the anode layer 2, a vacuum evaporation method, a sputtering method, or the like can be used. Alternatively, a commercially available material in which, for example, an ITO film is formed on the surface of a transparent substrate such as a glass substrate can be used.

As the organic solvent for preparing the solution for forming the charge transport layer, an electroluminescent material [specific block copolymer, copolymer (abc) or copolymer (ac)] to be used can be dissolved. Examples thereof include halogenated hydrocarbons such as chloroform, chlorobenzene, and tetrachloroethane, amide solvents such as dimethylformamide and N-methylpyrrolidone, ethyl lactate, pegmia, ethylethoxypropionate, and methylamyl. Ketone and the like. These organic solvents can be used alone or in combination of two or more. Among them, it is preferable to use an organic solvent having an appropriate evaporation rate, specifically, an organic solvent having a boiling point of about 70 to 150 ° C., in that a thin film having a uniform thickness can be obtained. The use ratio of the organic solvent varies depending on the type of the electroluminescent material, but is usually a ratio at which the concentration of the electroluminescent material in the charge transport layer forming solution is 0.1 to 10% by weight.
As a means for applying the charge transport layer forming solution, for example, a spin coating method, a dipping method, a roll coating method, an ink jet method, or the like can be used.

The conditions for the heat treatment of the coating film are appropriately set according to the type of the electroluminescent material, the presence or absence of the crosslinking agent, the type of the organic solvent, and the like. For 5 to 180 minutes.
The crosslinking reaction of the electroluminescent material can be performed only by heat treatment, but a crosslinking agent can be used for the purpose of accelerating the crosslinking reaction.
Examples of such a crosslinking agent include the above-mentioned copolymers [specific block copolymers, copolymers (abc) and copolymers (a
c)] can be used. Such a crosslinking agent may be added to the solution for forming the charge transport layer, and its use ratio is 10% by weight or less of the polymer constituting the electroluminescent material. However, from the viewpoint that a charge transporting layer with few impurities can be formed, it is preferable to perform a crosslinking reaction only by heat treatment without using a crosslinking agent.

The thus formed charge transport layer 10
On the surface of the light-emitting layer, a light-emitting layer forming solution in which a light-emitting material for forming a light-emitting layer is dissolved in an organic solvent is applied. The organic solvent in the film is removed and the light emitting layer 15 is removed.
Is formed. In the above, as the organic solvent for preparing the light emitting layer forming solution, various ones can be used as long as they can dissolve the light emitting material, and specific examples thereof include cyclohexanone and methyl isobutyl ketone. Ketones, cellosolves such as methyl cellosolve,
Examples include alcohols such as octanol, esters such as ethyl lactate and γ-butyrolactone, and halogenated organic compounds such as tetrachloroethane and chlorobenzene. The usage ratio of the organic solvent varies depending on the type of the light emitting material, but is usually a ratio at which the concentration of the light emitting material in the light emitting layer forming solution is 0.1 to 10% by weight. As a means for applying the light emitting layer forming solution, for example, a spin coating method, a dipping method, a roll coating method, an ink jet method, or the like can be used.

Then, on the surface of the formed light emitting layer 15,
For example, the cathode layer 3 is formed by a vacuum evaporation method or a sputtering method, and thus, the electroluminescent element having the configuration shown in FIG. 1 is manufactured.

In the above-described electroluminescent device, when a DC voltage is applied between the anode layer 2 and the cathode layer 3 by the DC power supply 5, the light emitting layer 15 emits light, and this light is emitted from the anode layer 2 and the glass. Radiated through the substrate 1.
According to the electroluminescent device having such a configuration, the charge transport layer 10 is made up of a unit (ABC) having a hole transporting structural unit and an electron transporting structural unit and a unit (AC) having a hole transporting structural unit. Since it is formed of such an electroluminescent material, the hole transporting ability and the electron transporting ability are efficiently exhibited, and as a result, a high luminous efficiency is obtained, and a high durability and a long service life are obtained. In addition, the charge transport layer 1
Since the unit (ABC) and the unit (AC) of the electroluminescent material for forming 0 are chain polymer components and are soluble in an organic solvent, the electroluminescent material is By preparing the dissolved charge transport forming solution, the charge transport layer 10 can be formed by a wet method. In addition, since each of the unit (ABC) and the unit (AC) has a crosslinkable structural unit, the formation of the charge transport layer 10 is performed by heat-treating the coating film with the solution for forming the charge transport layer. As a result of the cross-linking reaction of the polymer, a charge transport layer made of a cross-linked polymer can be formed. Therefore, when forming the light emitting layer 15,
Even if the light emitting layer forming solution is applied to the surface of the charge transport layer 10,
The charge transport layer 10 is not dissolved in the light emitting layer forming solution, whereby the intended light emitting layer 15 can be reliably formed without damaging the charge transport layer 10.

FIG. 2 is an explanatory sectional view showing a second example of the structure of the electroluminescent device of the present invention.
The electroluminescent element according to the first configuration example except that an electron transport layer 20 is provided on the light emitting layer 15 and the cathode layer 3 is provided on the electron transport layer 20. This is the same configuration as. Examples of the material constituting the electron transport layer 20 include metal complexes of quinoline-based compounds such as 8-hydroxyquinoline derivatives, bisnaphthyloxadiazole, pt-butylphenyl-biphenyl-oxadiazole, and 2-naphthyl-5-. An oxadiazole-based compound such as phenyl-oxadiazole, or a polymer containing these residues in a side chain can be used. Such an electron transport layer 20 is formed by a dry method such as a vacuum evaporation method or a sputtering method, or by dissolving an electron transport material in an appropriate solvent, and then applying the solution by a spin coating method, a dipping method, an inkjet method, a printing method, or the like. It can be formed by a wet method of coating and drying. In particular, by co-evaporating the above electron transport material and an alkali metal or an alkaline earth metal,
Preferably, the electron transport layer 20 is formed. According to the electroluminescent device according to the second configuration example,
The same effects as those of the electroluminescent device according to the first configuration example can be obtained. In addition, since the electron transport layer 20 is formed, the escape of holes (holes) is prevented, the transport of electrons is smoothed, the emission start voltage is further reduced, and the emission efficiency is further improved. Can be achieved.

FIG. 3 is an explanatory sectional view showing a third example of the structure of the electroluminescent device of the present invention.
This electroluminescent device has an electron transport layer 20
An electron injection layer 25 is provided thereon, and the electron injection layer 25
The configuration is the same as that of the electroluminescent element according to the second configuration example except that the cathode layer 3 is provided thereon. As a material constituting the electron injection layer 25, Li
Metal fluorides such as F, MgF ₂ and CsF, Al ₂ O ₃ ,
The electron injection layer 25, which can be appropriately selected from a compound such as a metal oxide such as SrO or a complex of a metal such as aluminum in consideration of the work function of the material constituting the anode and the electron transport layer and the LUMO level, Electron transport layer 20
May be formed over the entire surface or may be formed in a state of being scattered on the surface.
It may be about 20 nm. Such an electron injection layer 25 is
It can be formed by a dry method such as a vacuum evaporation method and a sputtering method. According to the electroluminescent element according to the third configuration example, the first configuration example and the second
The same effect as that of the electroluminescence according to the configuration example can be obtained. Further, since the electron injection layer 25 is formed, the injection of electrons from the anode becomes smooth, the light emission starting voltage is further reduced, and the light emission efficiency can be further improved.

FIG. 4 is an explanatory sectional view showing a fourth configuration example of the electroluminescent device of the present invention.
This electroluminescent element is provided on the anode layer 2.
A hole injection layer 30 is provided, and the charge transport layer 10 is provided on the hole injection layer 30 except that the first
This is the same configuration as the electroluminescent element according to the configuration example. Examples of the material constituting the hole injection layer 30 include copper phthalocyanine, polyaniline, polythiophene, and a complex of polydioxythiophene and polystyrene sulfonic acid commercially available under the trade name “PEDOT” (manufactured by Bayer AG). Such a hole injection layer 30 may be formed by a dry method such as a vacuum evaporation method or a sputtering method, or by dissolving an electron transport material in an appropriate solvent, and then applying the solution to a spin coating method, a dipping method, an inkjet method,
It can be formed by a wet method of applying and drying by a printing method or the like. The thickness is 1 to 100 nm. According to the electroluminescent element according to the fourth configuration example, the same effect as that of the electroluminescence element according to the above-described first configuration example can be obtained. Further, since the hole injection layer 30 is formed, a hole injection failure can be prevented.

FIG. 5 is an explanatory sectional view showing a fifth example of the structure of the electroluminescent device of the present invention.
The electroluminescent device according to the fourth configuration example is different from the electroluminescent device in that an electron transport layer 20 is provided on a light emitting layer 15 and a cathode layer 3 is provided on the electron transport layer 20. This is the same configuration as. As a material for forming the electron transport layer 20, the same material as the electroluminescent element according to the second configuration example can be used. According to the electroluminescence element according to the fifth configuration example, the same effects as those of the electroluminescence elements according to the first, second, and fourth configuration examples can be obtained.

FIG. 6 is an explanatory sectional view showing a sixth example of the structure of the electroluminescent element of the present invention.
This electroluminescent device has an electron transport layer 20
An electron injection layer 25 is provided thereon, and the electron injection layer 25
The configuration is the same as that of the electroluminescent element according to the fifth configuration example except that the cathode layer 3 is provided thereon. As a material for forming the electron injection layer 25,
The same element as the electroluminescent element according to the above configuration example can be used. According to the electroluminescent element according to the sixth configuration example, the same effects as those of the electroluminescent elements according to the first to fourth configuration examples can be obtained.

[0059]

Hereinafter, embodiments of the present invention will be described.
The present invention is not limited to these. In the following, “parts” means “parts by weight”.

(1) Synthesis of Copolymer: [Synthesis Example 1 (Synthesis of Specific Block Copolymer)] 9.5 mmol of N-vinylcarbazole as a monofunctional hole transporting monomer, and as a monofunctional electron transporting monomer 2-
β-naphthyl-5- (4-vinylphenyl) -1,3,3
0.5 mmol of 4-oxadiazole and 1 mmol of azobisisobutyronitrile as a radical polymerization catalyst were placed in a 100 ml pressure bottle under a nitrogen stream, and the nitrogen gas in the pressure bottle was repeatedly replaced. Was.
Further, 0.2 mmol of divinylbenzene (a mixture of a meta-form and a para-form) as a polyfunctional crosslinkable monomer and dehydrated dimethylformamide 5 as a polymerization solvent in a pressure bottle.
By adding 0 ml and polymerizing the monomer at 60 ° C. for 24 hours, a structural unit derived from N-vinylcarbazole, 2-β-naphthyl-5- (4-vinylphenyl) -1,3,4- Consisting of a structural unit derived from oxadiazole and a structural unit derived from divinylbenzene, and excluding the structural unit derived from divinylbenzene,
Structural units derived from -vinylcarbazole and structural units derived from 2-β-naphthyl-5- (4-vinylphenyl) -1,3,4-oxadiazole are present alternately;
A block component (abc) in which a structural unit derived from divinylbenzene is dispersed in a block component, and a block component (a) including a structural unit derived from N-vinylcarbazole and a structural unit derived from divinylbenzene
c) to obtain a specific block copolymer. In the above polymerization, a change in the composition of the reaction system was checked at regular intervals, and N-vinylcarbazole and 2-
β-naphthyl-5- (4-vinylphenyl) -1,3,3
The procedure was performed while confirming that 4-oxadiazole was alternately polymerized. Hereinafter, the obtained specific block copolymer is referred to as a specific block copolymer (1).

For the specific block copolymer (1) obtained, the structural unit derived from N-vinylcarbazole in the block component (abc) and 2-β-naphthyl-5- (4-vinylphenyl) -1, The ratio of the total of the structural units derived from 3,4-oxadiazole to the structural unit derived from N-vinylcarbazole in the block component (ac), the ratio of divinylbenzene in all the structural units, the block component (abc ) Weight average degree of polymerization,
Table 1 shows the weight average polymerization degree of the block component (ac) and the weight average molecular weight of the specific block copolymer.

[Synthesis Examples 2-3 (Synthesis of Specific Block Copolymer)] N-vinylcarbazole and 2-β-naphthyl-5- (4-vinylphenyl) -1,3,4-oxadiazole A specific block copolymer was obtained in the same manner as in Synthesis Example 1, except that the amount of divinylbenzene was changed to the amount shown in Table 1 below without changing the amount. Hereinafter, the specific block copolymers obtained in Synthesis Examples 2 and 3 are referred to as specific block copolymers (2) and (3). About the obtained specific block copolymers (2) and (3), a structural unit derived from N-vinylcarbazole in the block component (abc) and 2-β-naphthyl-5- (4-vinylphenyl) -1 Of the structural units derived from 2,3,4-oxadiazole and N in the block component (ac)
-Ratio with structural units derived from vinyl carbazole, ratio of divinylbenzene in all structural units, weight average polymerization degree of block component (abc), block component (a
Table 1 shows the weight average polymerization degree of c) and the weight average molecular weight of the specific block copolymer.

[Synthesis Example 4 (Synthesis of Copolymer (abc))] N-vinylcarbazole (90 mmol) as a monofunctional hole transporting monomer and 2-β-naphthyl-5- (4- as a monofunctional electron transporting monomer Vinylphenyl)-
By using 10 mmol of 1,3,4-oxadiazole and 2.5 mmol of divinylbenzene as a polyfunctional crosslinking monomer, the same operation as in Synthesis Example 1 was performed to obtain
2-β- structural unit derived from N-vinylcarbazole
Naphthyl-5- (4-vinylphenyl) -1,3,4-
It consists of a structural unit derived from oxadiazole and a structural unit derived from divinylbenzene. Excluding the structural unit derived from divinylbenzene, the structural unit derived from N-vinylcarbazole and 2-β-naphthyl-5- (4- A copolymer (abc) in which structural units derived from (vinylphenyl) -1,3,4-oxadiazole are alternately present, and structural units derived from divinylbenzene are dispersed in the copolymer. Obtained. The proportion of divinylbenzene in all structural units in the obtained copolymer (abc) and the weight average molecular weight of the copolymer (abc) are shown in Table 1 below.

[Synthesis Example 5 (Synthesis of Copolymer (ac))]
Using 100 mmol of N-vinylcarbazole as a monofunctional hole transporting monomer and 2.5 mmol of divinylbenzene as a polyfunctional crosslinkable monomer, the same operation as in Synthesis Example 1 was performed to obtain a structure derived from N-vinylcarbazole. A copolymer (ac) consisting of units and a structural unit derived from divinylbenzene was obtained. The ratio of divinylbenzene in all structural units in the obtained copolymer (ac) and the weight average molecular weight of the copolymer (ac) are shown in Table 1 below.

[0065]

[Table 1]

Comparative Comparative Example N-vinylcarbazole and 2-β-naphthyl-5- (4-vinylphenyl) -1,3,3 were obtained in the same manner as in Synthetic Example 1 except that divirbenzene was not used. A block component obtained by alternately polymerizing 4-oxadiazole (hereinafter referred to as a “block component (a
b) ". ) And a block component obtained by polymerizing N-vinylcarbazole (hereinafter referred to as “block component (a)”).
That. ) Was synthesized. In the obtained comparative block copolymer, the structural unit derived from N-vinylcarbazole in the block component (ab) and 2-β-naphthyl-5-
The molar ratio of the total of the structural units derived from (4-vinylphenyl) -1,3,4-oxadiazole to the structural units derived from N-vinylcarbazole in the block component (a) is 10: 90 and the block component (a
The weight average polymerization degree of b) is 25, the weight average polymerization degree of the block component (a) is 160, and the weight average molecular weight is 350
00.

(2) Preparation of Solution for Forming Charge Transport Layer: [Preparation Example 1] The specific block copolymer (1) obtained in Synthesis Example 1 was used as an electroluminescence material, and the specific block copolymer was used. (1) A charge transport layer forming solution was prepared by dissolving 2.4 parts of cyclohexanone solvent in 200 parts. Hereinafter, the obtained charge transport layer forming solution is referred to as a charge transport layer forming solution (1).

[Preparation Example 2] The procedure of Preparation Example 2 was repeated, except that the specific block copolymer (2) obtained in Synthesis Example 2 was used as a material for electroluminescence instead of the specific block copolymer (1). A charge transport layer forming solution was prepared in the same manner as in Example 1. Hereinafter, the obtained charge transport layer forming solution is referred to as a charge transport layer forming solution (2).

[Preparation Example 3] The procedure of Preparation Example 3 was repeated, except that the specific block copolymer (3) obtained in Synthesis Example 3 was used as an electroluminescent material instead of the specific block copolymer (1). A charge transport layer forming solution was prepared in the same manner as in Example 1. Hereinafter, the obtained charge transport layer forming solution is referred to as a charge transport layer forming solution (3).

[Preparation Example 4] Instead of the specific block copolymer (1), the copolymer (ab) obtained in Synthesis Example 4 was used.
c) 0.5 part of the copolymer (a) obtained in Synthesis Example 5
c) A charge transport layer forming solution was prepared in the same manner as in Preparation Example 1, except that 15.33 parts was used as the material for electroluminescence. Hereinafter, the obtained charge transport layer forming solution is referred to as a charge transport layer forming solution (4). Further, the used electroluminescent material [copolymer (ab)
c) with the copolymer (ac)], the sum of the hole transporting structural unit and the electron transporting structural unit in the copolymer (abc) [unit (ABC)], and the copolymer (ac) [ Unit (AC)] and the hole transporting structural unit in a molar ratio of 10:90.

[Preparation Example 5] Instead of one part of the specific block copolymer (1), the specific block copolymer (1)
20 parts, 18 parts of the copolymer (abc) and 18 parts of the copolymer (a
c) A charge transport layer forming solution was prepared in the same manner as in Preparation Example 1, except that 62 parts was used as a material for electroluminescence. Hereinafter, the obtained charge transport layer forming solution is referred to as a charge transport layer forming solution (5). In the electroluminescent material [mixture of specific block copolymer (1) and copolymer (abc) and copolymer (ac)] used, the block component of specific block copolymer (1) was used. (Abc) and the sum of the hole transporting structural unit and the electron transporting structural unit in the copolymer (abc) [unit (ABC)], the block component (ac) and the copolymer of the specific block copolymer (1) Coalescence (ac)
The ratio with the hole transporting structural unit in [unit (AC)] is 20:80 in molar ratio.

[Comparative Preparation Example 1] Instead of the specific block copolymer (1), the copolymer (ab) obtained in Synthesis Example 4 was used.
c) A charge transport layer forming solution for comparison was prepared in the same manner as in Preparation Example 1, except that 4.5 parts was used as the material for electroluminescence. Hereinafter, the obtained charge transport layer forming solution is referred to as a charge transport layer forming solution (6).

[Comparative Preparation Example 2] Instead of the specific block copolymer (1), the copolymer (a) obtained in Synthesis Example 5
c) A charge transport layer forming solution for comparison was prepared in the same manner as in Preparation Example 1 except that 2.4 parts was used as the material for electroluminescence. Hereinafter, the obtained charge transport layer forming solution is referred to as a charge transport layer forming solution (7).

[Comparative Preparation Example 3] Except that 3.0 parts of the comparative block copolymer obtained in Comparative Synthesis Example was used as an electroluminescent material instead of the specific block copolymer (1). In the same manner as in Preparation Example 1, a charge transport layer forming solution for comparison was prepared. Hereinafter, the obtained charge transport layer forming solution is referred to as a charge transport layer forming solution (8).

(3) Preparation of light emitting layer forming solution: A composition comprising polymethyl methacrylate / bisnaphthyloxadiazole / coumarin-6 (weight ratio = 29: 69: 2) was used as the light emitting material, and the light emitting material was used. The light emitting layer forming solution was prepared by dissolving 3 parts in 100 parts of cyclohexanone.

(4) Manufacture of Electroluminescence Element: <Manufacture Example 1> A 5 cm square glass substrate on which an ITO film (anode layer) was formed was prepared, and the I substrate formed on this glass substrate was prepared.
After applying the charge transport layer forming solution (1) obtained in Preparation Example 1 to the surface of the TO film using a spin coater, the obtained coating film was subjected to a heat treatment at 250 ° C. for 15 minutes. As a result, a charge transport layer having a thickness of 25 nm was formed. Next, after applying a light emitting layer forming solution to the surface of the charge transport layer, the obtained coating film was dried at 40 ° C. for 60 minutes to form a light emitting layer having a thickness of 60 nm. In forming the light emitting layer, the charge transport layer did not dissolve in the light emitting layer forming solution. Then, the thickness of the light emitting layer is 100
5 mm square magnesium / silver alloy (weight ratio: 1)
0: 1) By forming a film (cathode layer), an electroluminescent device having the configuration shown in FIG. 1 was manufactured.

<Production Example 2> An electroluminescent device was produced in the same manner as in Production Example 1 except that the charge transport layer forming solution (2) was used instead of the charge transport layer forming solution (1). In the formation of the light emitting layer in Production Example 2, the charge transport layer was not dissolved in the light emitting layer forming solution.

<Production Example 3> An electroluminescent device was produced in the same manner as in Production Example 1 except that the charge transport layer forming solution (3) was used instead of the charge transport layer forming solution (1). In the formation of the light emitting layer in Production Example 3, the charge transport layer did not dissolve in the light emitting layer forming solution.

<Production Example 4> An electroluminescent device was produced in the same manner as in Production Example 1, except that the charge transport layer forming solution (4) was used instead of the charge transport layer forming solution (1). In the formation of the light emitting layer in Production Example 4, the charge transport layer did not dissolve in the light emitting layer forming solution.

<Production Example 5> An electroluminescent device was produced in the same manner as in Production Example 1, except that the charge transport layer forming solution (5) was used instead of the charge transport layer forming solution (1). In the formation of the light emitting layer in Production Example 5, the charge transport layer did not dissolve in the light emitting layer forming solution.

<Comparative Production Example 1> An electroluminescent device was produced in the same manner as in Production Example 1, except that the charge transport layer forming solution (6) was used instead of the charge transport layer forming solution (1). In forming the light emitting layer in Comparative Production Example 1, the charge transport layer was not dissolved in the light emitting layer forming solution. <Comparative Production Example 2> An electroluminescent device was produced in the same manner as in Production Example 1, except that the charge transport layer forming solution (7) was used instead of the charge transport layer forming solution (1). In the formation of the light emitting layer in Comparative Production Example 2, the charge transport layer was not dissolved in the light emitting layer forming solution.

<Comparative Production Example 3> An ITO formed on a glass substrate in the same manner as in Production Example 1 except that the charge transport layer forming solution (8) was used instead of the charge transport layer forming solution (1). When a charge transport layer is formed on the surface of the film and a light emitting layer forming solution is applied to the surface of the charge transport layer, the charge transport layer dissolves in the light emitting layer forming solution and does not damage the charge transport layer. The light emitting layer could not be formed.

[Evaluation of Electroluminescent Element] (1) Luminance: Production Examples 1 to 5 and Comparative Production Examples 1 and 2
0 for each of the electroluminescent elements according to
By applying a DC voltage of −30 V, the electroluminescent element emits light, and the emission luminance of the element becomes
It measured with the luminance meter (-100 made by Minolta). (2) Durability: Each of the electroluminescent elements according to Production Examples 1 to 5 and Comparative Production Examples 1 and 2 was continuously illuminated under the condition that the initial light emission luminance was 300 cd / cm ^2, and the light emission luminance from the start of light emission (Half-life) of the electroluminescent element according to Comparative Production Example 2 was set to 100 (hereinafter, “half-life index”). Called.) The results are shown in Table 2 below.

[0084]

[Table 2]

As described above, according to Production Examples 1 to 5, the light emitting layer can be formed by the wet method without damaging the charge transporting layer. In addition, according to the electroluminescent elements according to Production Examples 1 to 5, it was confirmed that, compared to the electroluminescence elements according to Comparative Production Examples 1 and 2, a high luminous efficiency was obtained and excellent durability was obtained. .

[0086]

According to the electroluminescent material of the present invention, an electroluminescent device having high luminous efficiency and excellent durability can be obtained, and the organic material layer in the electroluminescent device can be formed by a simple process. It can be formed reliably. According to the electroluminescence device of the present invention, high luminous efficiency and excellent durability can be obtained, and the organic material layer can be surely formed by a simple process. According to the method for manufacturing an electroluminescent device of the present invention, an electroluminescent device having high luminous efficiency and excellent durability can be manufactured, and the organic material layer in the electroluminescent device can be reliably formed by a simple process. Can be formed.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view showing a first configuration example of an electroluminescence element according to the present invention.

FIG. 2 is an explanatory cross-sectional view showing a second configuration example of the electroluminescent element according to the present invention.

FIG. 3 is an explanatory cross-sectional view showing a third configuration example of the electroluminescent element according to the present invention.

FIG. 4 is an explanatory cross-sectional view showing a fourth configuration example of the electroluminescence element according to the present invention.

FIG. 5 is an explanatory sectional view showing a fifth configuration example of the electroluminescent element according to the present invention.

FIG. 6 is an explanatory cross-sectional view illustrating a sixth configuration example of the electroluminescent element according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent substrate 2 Anode layer 3 Cathode layer 5 DC power supply 10 Charge transport layer 15 Light emitting layer 20 Electron transport layer 25 Electron injection layer 30 Hole injection layer

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H05B 33/14 H05B 33/14 A (72) Inventor Mitsuhiko Sakakibara 2-11-24 Tsukiji, Chuo-ku, Tokyo Japan JS Stock Inside the company (72) Inventor Yasunori Negoro 2-11-24 Tsukiji, Chuo-ku, Tokyo Inside JSR Co., Ltd. (72) Inventor Hiroyuki Yasuda 2-11-24 Tsukiji, Chuo-ku, Tokyo Inside JSR Co., Ltd. (72 ) Inventor Tetsu Tanaka 629 Oshiba, Mobara-shi, Chiba Futaba Electronics Co., Ltd. (72) Inventor Tatsuo Fukuda 629 Oshiba, Mobara-shi, Chiba Futaba Electronics Co., Ltd. DB03 EB00 FA01 4J002 BC12X BJ00W BJ00X BP03Y GH00 GQ00 HA05 4J026 HA07 HA08 HA10 HA11 HA19 HA20 HA22 HA24 HA28 HA29 HA32 HA38 HA39 HB07 HB10 HB11 HB19 HB20 HB22 HB24 HB28 HB29 HB32 HB38 HB48

Claims (7)

[Claims] 1. A unit (AC) comprising 80 to 100 mol% of a structural unit derived from a monofunctional hole transporting monomer and 0 to 20 mol% of a structural unit derived from a polyfunctional crosslinking monomer. Structural unit 40- derived from monomer
A unit consisting of 60 mol%, 40 to 60 mol% of structural units derived from a monofunctional electron transporting monomer, and 0 to 20 mol% of structural units derived from a polyfunctional crosslinking monomer (AB
C), and the sum of the structural units derived from the monofunctional hole transporting monomer and the structural units derived from the monofunctional electron transporting monomer in the unit (ABC), and the unit (A
The ratio with the structural unit derived from the monofunctional hole transporting monomer in C) is 50:50 to 5:95 in molar ratio, and the total structure constituting the unit (AC) and the unit (ABC) An electroluminescent material, wherein the ratio of the structural unit derived from the polyfunctional crosslinking monomer in the unit is 0.1 to 10 mol%. 2. The unit (ABC) comprises a structural unit derived from a monofunctional hole transporting monomer and a structural unit derived from a monofunctional electron transporting monomer, except for a structural unit derived from a polyfunctional crosslinking monomer. And the structural unit derived from the polyfunctional crosslinking monomer is the unit (AB)
2. The material for electroluminescence according to claim 1, wherein the material is present in a dispersed state in C). 3. The electro-polymer according to claim 1, wherein the block copolymer is composed of a block component composed of a unit (AC) and a block component composed of a unit (ABC). Luminescent material. 4. A copolymer comprising units (AC),
The electroluminescent material according to claim 1 or 2, wherein the resin composition is a resin composition comprising a copolymer comprising a unit (ABC). 5. A block copolymer composed of a block component composed of a unit (AC) and a block component composed of a unit (ABC), a copolymer composed of a unit (AC), and a copolymer composed of a unit (ABC). The material for electroluminescence according to claim 1 or 2, which is a resin composition comprising a polymer. 6. An electroluminescent device comprising at least an anode layer, a charge transport layer obtained from the electroluminescent material according to claim 1, a light emitting layer, and a cathode layer. Luminescent element. 7. The method according to claim 1, wherein the charge transport layer is formed on
A charge transport layer formed by dissolving the electroluminescent material according to any one of claims 1 to 5 in an organic solvent and applying a heat treatment to form a charge transport layer. A method for producing an electroluminescent device, comprising a step of forming a light-emitting layer by applying a light-emitting layer forming solution in which a light-emitting material is dissolved in an organic solvent to a surface of a transport layer and performing a drying treatment. .