JP2002047271A - Carbazole derivative, carbazole-based polymer and hole- transporting material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new carbazole derivative capable of providing a carbazole-based polymer having excellent hole-transporting ability and durability, and suitable as a hole-transporting material, and further to provide the carbazole-based polymer suitable as the hole-transporting material, and the hole-transporting material having the excellent hole-transporting ability and the durability. SOLUTION: This carbazole derivative is represented by formula (1), and the carbazole-based polymer is represented by formula (2) (in the formulas (1) and (2), R1 to R5 are each hydrogen, an alkyl group, a phenyl group or the like; and X is a single bond, a phenylene group or the like). The hole- transporting material includes the carbazole-based polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbazole derivative, a carbazole-based polymer, and a hole transporting material. More specifically, for example, a carbazole derivative and a carbazole-based polymer suitably used for obtaining an electroluminescence device and the like, and It relates to a hole transport material.

[0002]

2. Description of the Related Art In recent years, organic materials have begun to be used as a hole transporting material and an electron transporting material constituting an electroluminescent device. An organic electroluminescent device using such an organic material (hereinafter referred to as "organic EL device") has been developed.
Also called an "element." ) Is being actively researched. An organic material constituting such an organic EL element is required to have excellent durability and to obtain high luminous efficiency.

Conventionally, organic materials having a hole transporting property include diamine derivatives, N, N'-diphenyl-N,
Low molecular weight organic materials such as aromatic amine compounds such as N′-di (3-methylphenyl) -4,4 ′, diaminobiphenyl (hereinafter also referred to as “m-TPD”), and polymers such as polyvinylcarbazole Organic materials are known.
However, since the above-mentioned low-molecular organic material has poor physical or thermal durability, when the hole transport layer is formed by the low-molecular organic material, the organic EL element is driven or stored. During the hole transport layer will be altered,
There is a disadvantage that. In addition, since a high molecular weight organic material such as polyvinyl carbazole has a very high glass transition point (Tg), a hole transport layer having excellent durability, that is, a long service life can be obtained. And the luminous efficiency is low due to insufficient hole transport performance, which poses a practical problem.

[0004]

SUMMARY OF THE INVENTION The present invention has been made based on the above circumstances, and the first aspect of the present invention has been made.
An object of the present invention is to provide a novel carbazole derivative having excellent hole transporting performance and durability and capable of obtaining a carbazole-based polymer suitable as a hole transporting material. A second object of the present invention is to provide a carbazole polymer having excellent hole transport performance and durability and suitable as a hole transport material. A third object of the present invention is to provide a hole transporting material having excellent hole transporting performance and durability.

[0005]

The carbazole derivative of the present invention is represented by the following general formula (1).

[0006]

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[Wherein, R¹Represents a hydrogen atom, an alkyl group or
Represents a phenyl group;^Two, R^Three, R ^FourAnd R^FiveIs
Each independently a hydrogen atom, an alkyl group, an alkoxy group,
It represents a phenyl group or a dialkylamino group. X is simply
Bond or phenylene group, carbonyl group or this
Represents a divalent organic group containing one or both of
You. ]

The carbazole polymer of the present invention is characterized by having a structural unit represented by the following general formula (2).

[0009]

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[Wherein, R¹Represents a hydrogen atom, an alkyl group or
Represents a phenyl group;^Two, R^Three, R ^FourAnd R^FiveIs
Each independently a hydrogen atom, an alkyl group, an alkoxy group,
It represents a phenyl group or a dialkylamino group. X is simply
Bond or phenylene group, carbonyl group or this
Represents a divalent organic group containing one or both of
You. ]

The carbazole polymer of the present invention preferably contains the structural unit represented by the general formula (2) in an amount of 5% by mass or more.

The hole transport material of the present invention contains the carbazole polymer or a hole transport material containing the carbazole polymer and a polymer other than the carbazole polymer. A material, wherein the proportion of the structural unit represented by the general formula (2) in the entire polymer is 5% by mass or more.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

<Carbazole Derivative> The carbazole derivative of the present invention is represented by the above general formula (1). In the general formula (1), R ¹ represents a hydrogen atom, an alkyl group or a phenyl group. Here, specific examples of the alkyl group include an alkyl group having 1 to 18 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, and a dodecyl group. In the general formula (1), R ¹ is preferably an alkyl group having 1 to 3 carbon atoms such as a methyl group or an ethyl group, or a hydrogen atom.

In addition, R ² , R ³ ,
R ⁴ and R ⁵ represent a hydrogen atom, an alkyl group, an alkoxy group, a phenyl group or a dialkylamino group, all of which may be the same or a part or all thereof may be different.

Here, the alkyl group is not particularly limited, but is preferably an alkyl group having 1 to 8 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group and an octyl group. . In particular, when a polymer obtained from this carbazole derivative is used as a hole transporting material, in terms of obtaining high hole transporting performance,
A methyl group is preferable, and an alkyl group having a large number of carbon atoms (for example, having 8 carbon atoms) is preferable in that a polymer having high solubility in an organic solvent can be obtained. The alkoxy group is not particularly limited, but has 1 carbon atom such as a methoxy group, an ethoxy group, a propoxy group and a butoxy group.
To 8 are preferable, and particularly when a polymer obtained from this carbazole derivative is used as a hole transport material, high hole transport performance is obtained.
A methoxy group is preferred. As the dialkylamino group,
Although not particularly limited, a dimethylamino group, a diethylamino group, a dipropylamino group or the like having 1 carbon atom
Those having an alkyl group of from 8 to 8 are preferable, and in particular, when a polymer obtained from this carbazole derivative is used as a hole transporting material, a di-n-propylamino group, A di-i-propylamino group is preferred.

In the general formula (1), as a combination of R ² and R ³ , one of the two is a hydrogen atom and the other is an alkyl group.
^As a combination of ⁴ and R ⁵ , one in which either one is a hydrogen atom and the other is an alkyl group is preferable. Further, when each of R ^{2 to} R ⁵ is other than a hydrogen atom, it is preferable that each position is meta-position or para-position.

In the general formula (1), X represents a single bond, a phenylene group, a carbonyl group, or a divalent organic group containing one or both of them. Examples of the divalent organic group containing a carbonyl group include -COO-
(Oxycarbonyl group), -CONH- (iminocarbonyl group) or -CONHC
And a group represented by O- (ureylene group). Examples of the divalent organic group containing a phenylene group include -C
_And a group represented by ₆ H ₄ CH ₂ O—. Examples of the divalent organic group containing both a carbonyl group and a phenylene group include a group represented by the following formula (A) and a group represented by the following formula (B). here,
A phenylene group and a divalent organic group containing the same are represented by o
-, M-, or p-form,
It is preferably a body. In the general formula (1), X is preferably a group represented by the formula (A), a group represented by the formula (B), or a phenylene group.

[0019]

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[0020]

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[Wherein the number of repetitions n is 1 to 10. ]

Preferred specific examples of the carbazole derivative represented by the general formula (1) are, for example, those represented by the following formula (a), those represented by the following formula (b), and those represented by the following formula (c). And those represented by the following formula (d).

[0023]

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[0024]

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Such a carbazole derivative represented by the general formula (1) is obtained by, for example, starting from carbazole, a hydrogen atom bonded to the nitrogen of the carbazole and a hydrogen atom bonded to each carbon atom at the position numbers 3 and 6. It can be obtained by performing various substitution reactions on atoms. As a specific example, a method for producing the carbazole derivative represented by the above formula (a) will be described. First, a carbazole is reacted with, for example, nitrobenzene, so that a hydrogen atom bonded to the nitrogen of the carbazole is converted to a nitrophenyl group. And further, for example, by reacting bromine, the hydrogen atom bonded to each of the carbon atoms at position numbers 3 and 6 is replaced with a bromine atom, whereby the intermediate product (A) (3,6- Dibromo [N- (p-nitrophenyl) carbazole] is obtained. This synthesis step is shown in reaction formula (i).

[0026]

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The intermediate product (A) thus obtained
And the intermediate product (B) (3,6-bis (m-tolylphenylamino) [N- (p -Nitrophenyl) carbazole]), and the nitro group is converted to an amino group by, for example, performing a hydrogenation reaction on the intermediate product (B), whereby the intermediate product (C) (3,6- Bis (m-tolylphenylamino) [N- (p-aminophenyl) carbazole] is obtained. This synthesis step is represented by reaction formula (ii)
And the reaction formula (iii).

[0028]

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[0029]

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By reacting the obtained intermediate product (C) with, for example, methacryloyl chloride, a carbazole derivative represented by the formula (a) can be produced.

A method for producing the carbazole derivative represented by the formula (b) will be described. The carbazole derivative represented by the formula (b) can be produced by synthesizing the product (C) and reacting the intermediate product (C) with, for example, 2-isocyanatoethyl methacrylate.

<Carbazole Polymer> The carbazole polymer (carbazole derivative polymer) of the present invention has a structural unit represented by the general formula (2) (hereinafter, referred to as “specific structural unit”). Is obtained by polymerizing or copolymerizing the carbazole derivative represented by the general formula (1).

The carbazole polymer of the present invention comprises only a specific structural unit, that is, a carbazole derivative monomer represented by the general formula (1) (hereinafter, referred to as “specific monomer”) alone. Even a polymer having a specific structural unit and another structural unit, that is, a specific monomer and a monomer copolymerizable therewith (hereinafter, referred to as a “copolymerizable monomer”). And a copolymer of

In the carbazole polymer of the present invention,
In the case of a copolymer of a specific monomer and a copolymerizable monomer, the content of the specific structural unit is 5% by mass or more, particularly 1%.
It is preferably at least 0% by mass. When the content of the specific structural unit is less than 5% by mass, when this carbazole-based polymer is used as a hole transport material, the hole transport performance and durability tend to be low.

As the copolymerizable monomer, for example, N-vinylcarbazole, N- (4-vinylphenyl)
Carbazole derivatives other than specific monomers such as carbazole and N-biphenylvinylcarbazole;
A vinyl aromatic amine such as a compound represented by the following formula (f), a compound represented by the following formula (g), p-vinyltriphenylamine, p-methacryloyltriphenylamine, etc. Monomers having a hole transporting ability can be mentioned, and N-vinylcarbazole is particularly preferred. These copolymerizable monomers can be used alone or in combination of two or more.

[0036]

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The weight average molecular weight of such a carbazole polymer is, for example, from 1,000 to 100,000 in terms of polystyrene by gel permeation chromatography.
0, particularly preferably 5000 to 300,000. When the weight average molecular weight is less than 1000, the obtained hole transporting material may be insufficient in 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 obtained hole transport material tends to have a remarkably high solution viscosity, and when the organic EL device is manufactured using the hole transport material, the handling property is poor. And the stringiness of the solution occurs, which is not preferable. Further, the ratio M between the weight average molecular weight and the number average molecular weight M
w / Mn is not particularly limited, but is preferably a polymer having a uniform molecular weight, that is, a polymer having a relatively small ratio Mw / Mn.

The carbazole polymer can be prepared by subjecting a specific monomer or a mixture of a specific monomer and a copolymerizable monomer to an appropriate polymerization method, for example, a radical polymerization method, an anion polymerization method or a cationic polymerization method. And can be produced by polymerization. In order to obtain a carbazole polymer having a narrow molecular weight distribution, a living radical polymerization method, a living anion polymerization method or a living cation polymerization method is used.

When a carbazole-based polymer is obtained by a usual radical polymerization method, azo compounds such as azobisisobutyronitrile (AIBN), peroxides such as benzoyl peroxide (BPO), and tetraethylthiuram disulfide are used. A radical polymerization method using a known radical initiator such as a dithiocarbamate derivative as a polymerization catalyst can be used. When a carbazole polymer is obtained by a living radical polymerization method,
A living radical polymerization method using a catalyst system in which an N-oxy radical such as 2,6,6-tetramethyl-1-piperidine-N-oxide (TEMPO) is combined with the above radical polymerization initiator, atom transfer polymerization, or the like. A living radical polymerization method can be used. The usage ratio of such a radical polymerization catalyst is 1 to 0.00001 mol per 1 mol of the monomer. In such a radical polymerization method, as a polymerization solvent, an amide solvent such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, benzene, toluene,
Xylene, hexane, hydrocarbon solvents such as cyclohexane, γ-butyrolactone, ester solvents such as ethyl lactate, cyclohexylbenzophenone, cyclohexanone, 2-ethylpentanone, ketone solvents such as ethyl isoamyl ketone, cyclic ethers such as tetrahydrofuran and Ether solvents such as aliphatic ethers such as diethylene glycol dimethyl ether can be used. The reaction temperature is, for example, 0 to 200 ° C., and the reaction time is, for example, 0.5 to 72 hours.

When a carbazole polymer is obtained by a usual anionic polymerization method, for example, an olefin catalyst such as naphthyl sodium, an alkyllithium such as methyllithium, ethyllithium and butyllithium, an aryllithium such as phenyllithium, diethylzinc An anion polymerization method using an organometallic compound of a metal such as an alkali metal or an alkaline earth metal such as an alkyl complex such as alkyl zinc, lithium alkyl magnesium or lithium alkyl barium as an anion polymerization catalyst can be used. In particular, it is preferable to use an organic lithium compound such as n-butyllithium, sec-butyllithium, and phenyllithium as the anion polymerization catalyst. When a carbazole polymer is obtained by a living anionic polymerization method, butyl lithium,
A living anionic polymerization method using a catalyst such as ethyl lithium or ethyl sodium can be used. The use ratio of such an anionic polymerization catalyst is 1.0 to 0.0001 mol per 1 mol of the monomer. In such an anionic polymerization method, as a 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 to 100 ° C., and the reaction time is:
For example, 0.25 to 48 hours.

When a carbazole-based polymer is obtained by a usual cationic polymerization method, a known cationic polymerization catalyst such as a Lewis acid such as trifluoroborate and tin tetrachloride, an inorganic acid such as sulfuric acid and hydrochloric acid, and a cation exchange resin is used. The cationic polymerization method used can be used. Also,
When a carbazole polymer is obtained by a living cationic polymerization method, a living cationic polymerization method using a catalyst such as HI or HI-ZnI ² can be used. The use ratio of such a cationic polymerization catalyst is 0.01 to 0.00001 mol per 1 mol of the monomer. In such a cationic polymerization method, polymerization solvents include halogenated hydrocarbons represented by methylene chloride and chlorobenzene, cyclic ethers such as dibutyl ether, diphenyl ether, dioxane and tetrahydrofuran, and highly polar solvents such as acetonitrile and nitrobenzene. Etc. can be used. The reaction temperature is, for example, -150 to 50 ° C, and the reaction time is, for example, 0.5 minutes to 24 hours.

<Hole Transport Material> The hole transport material of the present invention is a carbazole polymer having a specific structural unit represented by the general formula (2) (hereinafter, referred to as a “specific carbazole polymer”). Is contained. This hole transporting material includes a specific carbazole polymer and a polymer other than the specific carbazole polymer (hereinafter referred to as “other ).) Here, the specific carbazole polymer is
One type may be used alone, or two or more types may be used in combination.

When the hole transport material of the present invention comprises a specific carbazole polymer and another polymer, the content of the specific structural unit in the total polymer is 5% by mass or more, particularly 10% by mass. % Is preferable. When the content ratio of the specific structural unit is less than 5% by mass,
An organic EL device constituted by using this hole transport material,
The light emission starting voltage is high, the light emission efficiency is low, and the durability is low.

Other polymers include, for example, polyvinyl carbazole, poly (4-vinylphenyl) carbazole, polyvinyltriphenylamine, vinylcarbazole and 2- (4-vinylphenyl) -5-naphthyl-1,3,3 Examples thereof include known polymers having a hole-transporting ability such as a copolymer with 5-oxadiazole. Preferably, poly (4-vinylphenyl) carbazole, polyvinyltriphenylamine, vinylcarbazole and 2- (4-vinylphenyl) -5-naphthyl-1,
Copolymers with 3,5-oxadiazole can be mentioned. One or more of these other polymers may be contained in the hole transport material.

Further, various dyes, laser dyes and the like may be added to the hole transport material of the present invention. And the amount of addition is 0.1 to the total mass of the hole transporting material.
The ratio is 1 to 10% by mass. For hole transport materials,
When a dye, a laser dye, or the like is added, the organic EL element formed using the hole transport material promotes light emission and has a long service life.

[0046]

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

[Synthesis of Carbazole Derivative] <Derivative Synthesis Example 1> In a flask equipped with a reflux device, 20 g of carbazole as a starting material, 15 g of potassium hydroxide as a metalating agent, and 80 ml of nitrobenzene were added in this order, and the mixture was added at room temperature. After stirring at 80 ° C., the temperature was raised to 80 ° C. over 1 hour while stirring the system.
After stirring for an hour, the system was immediately heated to 90 ° C.
The reaction solution was obtained by stirring for 5 hours. The obtained reaction solution was cooled and then filtered, and the obtained reaction product was dissolved in acetic acid and recrystallized to obtain a reaction product 15.
g was collected. It was confirmed that the obtained reaction product was N- (p-nitrophenyl) carbazole (hereinafter, referred to as “compound (1)”).

In a three-necked flask equipped with a dropping funnel, 5 g of compound (1) and 80 ml of acetic acid were charged, and after dissolving compound (1) in acetic acid, 8.2 g of bromine was added dropwise to this system at room temperature. A reaction solution was obtained by reacting for an hour. The obtained reaction solution was poured into 400 ml of ice water, and the reaction product was precipitated and collected, and was dissolved in tetrahydrofuran (THF) and recrystallized.
7 g of reaction product were obtained. The reaction product obtained is 3,6
-Dibromo [N- (p-nitrophenyl) carbazole] (hereinafter, referred to as “compound (2)”).

In an inert gas atmosphere, 5 g of compound (2) and tris (dibenzylideneacetone) dipalladium (Pd ₂ (db) were placed in a three-necked flask equipped with a reflux device.
a) ₃ ) 3100 mg and 3 g of sodium-t-butoxide were dissolved in 300 ml of m-xylene, and 6.2 g of m-tolylphenylamine and 91 mg of tris (t-butyl) phosphine were added thereto. After stirring at room temperature, the reaction was carried out by heating the system at 120 ° C. for 2 hours. The reaction solution was analyzed by high performance liquid chromatography (HPLC) to confirm that the reaction was completed. The reaction solution was washed with brine, then extracted with ether, dehydrated and dried, and then the solvent was removed. Then, a reaction product (solid) was obtained. The reaction product was dissolved in acetone, and purified by precipitation using methanol to recover 6 g of a reaction product. It was confirmed that the obtained reaction product was 3,6-bis (m-tolylphenylamino) [N- (p-nitrophenyl) carbazole] (hereinafter, referred to as “compound (3)”). .

A pressure reactor was charged with 5 g of compound (3) and palladium carbon (supporting 5% of palladium) in an amount of 10% by mass as a catalyst, and subjected to a hydrogenation reaction in the presence of a dimethylformamide (DMF) solvent. I let it. Thereafter, the catalyst was separated by filtration and purified using a column to obtain a reaction product. The obtained reaction product was 3,6-bis (m-tolylphenylamino) [N-
(P-aminophenyl) carbazole] (hereinafter referred to as “compound 4”), and its purity was 9
7% and the yield was 85%.

After reacting 3.1 g of the compound (4) with 0.53 g of methacryloyl chloride in the presence of twice the molar amount of triethylamine (a dehydrochlorinating agent) of the compound (4), triethylamine produced The reaction product was obtained by removing the hydrochloride and the remaining triethylamine. The obtained reaction product was analyzed for infrared absorption spectrum and nuclear magnetic resonance spectrum. The reaction product was found to be a carbazole derivative represented by the formula (a) (hereinafter referred to as “derivative (1)”). ) Was confirmed. The yield of the derivative (1) was 85%. FIG. 1 shows an infrared absorption spectrum, and FIG. 2 shows a nuclear magnetic resonance spectrum.

<Derivative Synthesis Example 2> Compound (4) was synthesized in the same manner as in Synthesis Example 1, 5 g of this compound (4) was dissolved in toluene in a flask equipped with a dropping funnel, and 2-isocyanatoethyl was added to the solution. Methacrylate 1.3
g was contacted dropwise at -70 ° C, and the temperature of the system was gradually raised to 30 ° C to complete the reaction. This reaction was quantitative. A reaction product was obtained by separating the obtained reaction solution using a column. The obtained reaction product was analyzed for infrared absorption spectrum and nuclear magnetic resonance spectrum. The reaction product was found to be a carbazole derivative represented by the above formula (b) (hereinafter referred to as “derivative (2)”). ) Was confirmed. Further, the purity of the derivative (2) was 98%. FIG.
FIG. 4 shows an infrared absorption spectrum, and FIG. 4 shows a nuclear magnetic resonance spectrum.

[Synthesis of carbazole-based polymer] <Polymer synthesis example 1> After replacing the inside of a pressure-resistant bottle having a volume of 50 ml with nitrogen gas, 20 mmol of the derivative (1) was introduced into the pressure-resistant bottle under a nitrogen stream. And 10 ml of N, N-dimethylformamide were charged, and the derivative (1) was dissolved in N, N-dimethylformamide.
While stirring this solution, 2 mmol of azobisisobutyronitrile as a radical polymerization catalyst was added to the solution, and the temperature of the system was raised from room temperature to 70 ° C. to increase the reaction temperature to 70 ° C.
Radical polymerization was carried out at a temperature of 18 ° C. for a reaction time of 18 hours to obtain a polymer solution. The polymer was coagulated by pouring the obtained polymer solution into 50 times the amount of methanol to recover the polymer. The polymer was purified by reprecipitation by a conventional method, and then dried under reduced pressure at 50 ° C. for 1 day. Hereinafter, the obtained polymer is referred to as polymer (A-
1). The obtained polymer (A-1) was subjected to a spectral analysis of an infrared absorption spectrum. As a result, the polymer (A-1) was found to be a carbazole-based polymer having the specific structural unit represented by the formula (a). It was confirmed that they were united. FIG. 5 shows an infrared absorption spectrum diagram.

The weight average molecular weight Mw of the polymer (A-1) is calculated by gel permeation chromatography (solvent: tetrahydrofuran) in terms of polystyrene.
10,300, and the ratio Mw / Mn between the weight average molecular weight and the number average molecular weight was 1.5.

<Polymer Synthesis Example 2> A polymer was obtained in the same manner as in Polymer Synthesis Example 1 except that 20 mmol of the derivative (1) was used instead of 20 mmol of the derivative (1). Hereinafter, the obtained polymer is referred to as polymer (A-2). The obtained polymer (A-2) was subjected to a spectral analysis of an infrared absorption spectrum and a nuclear magnetic resonance spectrum. As a result, the polymer (A-2) was found to have a specific structural unit represented by the above formula (b). It was confirmed to be a carbazole polymer composed of FIG. 6 shows an infrared absorption spectrum and FIG. 7 shows a nuclear magnetic resonance spectrum.

The weight average molecular weight Mw of the polymer (A-2) is calculated by gel permeation chromatography (solvent: tetrahydrofuran) in terms of polystyrene.
28,000, and the ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 1.65.

<Synthesis Example 3> Same as Polymer Synthesis Example 1 except that 20 mmol of the derivative (2) was used instead of 20 mmol of the derivative (1), and 20 mmol of N-vinylcarbazole was used together. To obtain a polymer. Hereinafter, the obtained polymer is referred to as a polymer (A-3). Also,
The carbazole polymer (A-3) was subjected to spectral analysis of infrared absorption spectrum. As a result, a carbazole composed of the specific structural unit represented by the formula (b) and a structural unit derived from N-vinylcarbazole was obtained. It was confirmed to be a polymer. FIG. 8 shows an infrared absorption spectrum diagram.

The weight average molecular weight Mw of the polymer (A-3) is calculated by gel permeation chromatography (solvent: tetrahydrofuran) in terms of polystyrene.
20,000, and the ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 1.65. Then, the polymer (A
-3) contained a specific structural unit of 50% by mass.

<Polymer Synthesis Example 4> Except that 20 mmol of the derivative (1) was used instead of 20 mmol of the derivative (1), and 10 mmol of the compound represented by the formula (c) was used together, A polymer was obtained in the same manner as in Combination Synthesis Example 1. Hereinafter, the obtained polymer is referred to as a polymer (A-4).
Further, with respect to the carbazole-based polymer (A-4),
As a result of spectral analysis of an infrared absorption spectrum, a carbazole-based compound comprising a specific structural unit represented by the formula (b) and a structural unit derived from a copolymerizable monomer represented by the formula (c) The polymer was confirmed to be a polymer. FIG. 9 shows an infrared absorption spectrum diagram.

The weight average molecular weight Mw of the polymer (A-4) is calculated by gel permeation chromatography (solvent: tetrahydrofuran) in terms of polystyrene.
28,000, and the ratio Mw / Mn of the weight average molecular weight to the number average molecular weight was 1.65. Then, the polymer (A
-4) contained 70% by mass of the specific structural unit.

[Production of Test Element] <Production Example 1> A polymer (A-1) was used as a hole transport material, and this was dissolved in tetrachloroethane as an organic solvent to form a hole transport layer. A coating solution was prepared. The coating liquid for forming a hole transport layer is applied by a spin coater onto a transparent substrate made of a 5 cm square glass substrate having an anode made of an ITO film formed on its surface, and then subjected to an organic solvent removal treatment. Then, a hole transport layer having a thickness of 25 nm made of the hole transport material of the present invention was formed. Next, on this hole transport layer, a light emitting layer made of trisquinolinolate aluminum having a thickness of 50 nm is formed by a vapor deposition method, and further thereon, a light emitting layer of 5 nm at 200 nm is formed.
By forming a cathode made of a square aluminum film, two test devices were produced. Hereinafter, the manufactured test device is referred to as a test device (1).

<Production Example 2> Two test elements were prepared in the same manner as in Production Example 1 except that the polymer (A-2) obtained in Polymer Synthesis Example 2 was used as the hole transport material. Produced.
Hereinafter, the manufactured test element is referred to as a test element (2).

<Production Example 3> Two test elements were prepared in the same manner as in Production Example 1 except that the polymer (A-3) obtained in Polymer Synthesis Example 3 was used as the hole transporting material. Produced.
Hereinafter, the manufactured test element is referred to as a test element (3).

<Production Example 4> Two test elements were prepared in the same manner as in Production Example 1 except that the polymer (A-4) obtained in Polymer Synthesis Example 4 was used as the hole transporting material. Produced.
Hereinafter, the manufactured test element is referred to as a test element (4).

<Production Example 5> As the hole transport material, the polymer (A-2) obtained in Polymer Synthesis Example 2, N-vinylcarbazole and 2- (4-vinylphenyl) -5-naphthyl- 1,3,4-oxadiazole copolymer (molar ratio 9: 1, weight average molecular weight (Mw) 19000)
) Were prepared in the same manner as in Production Example 1 except that a mixture of 1: 1 was used. Hereinafter, the manufactured test element is referred to as a test element (5). This hole transporting material contained 50% by mass of a specific structural unit in all the polymers.

<Comparative Production Example 1> N was used as the hole transport material.
-Two test elements were produced in the same manner as in Production Example 1 except that polyvinyl carbazole was used. Hereinafter, the manufactured test element is referred to as a comparative test element (1).

[Evaluation of Test Element] Light-emission starting voltage and maximum light-emitting luminance: Production Examples 1 to 5
DC voltage was applied to each of the test elements (1) to (5) and the comparative test element (1) according to Comparative Production Example 1 using an ITO film as an anode and an alloy film of magnesium and silver (MgAg) as a cathode. Is applied to cause the light emitting layer to emit light, and the maximum light emission luminance is measured by a luminance meter “LS-10”.
0 "(Minolta). In addition, the light emission starting voltage at that time is measured with a voltmeter “R8240” (ADVANT).
EST). The results are shown in Table 1 below.

[0068]

[Table 1]

As is clear from Table 1, according to the test elements (1) to (5) according to Production Examples 1 to 5, compared with the comparative test element (1) according to Comparative Production Example 1, It was confirmed that the hole transport performance was high.

[0070]

The carbazole derivative of the present invention is a novel carbazole derivative. According to this carbazole derivative, it has excellent hole transport performance and durability, and is suitable as a hole transport material. A polymer can be obtained. The carbazole-based polymer of the present invention has excellent hole transport performance and durability, and is suitable as a hole transport material. Since the hole transport material of the present invention contains the above-mentioned carbazole polymer, it has excellent hole transport performance and durability.

[Brief description of the drawings]

FIG. 1 is an infrared absorption spectrum of a carbazole derivative according to Derivative Synthesis Example 1 in Examples.

FIG. 2 is a nuclear magnetic resonance spectrum of a carbazole derivative according to a derivative synthesis example 1 in Examples.

FIG. 3 is an infrared absorption spectrum of a carbazole derivative according to derivative synthesis example 2 in Examples.

FIG. 4 is a nuclear magnetic resonance spectrum of a carbazole derivative according to derivative synthesis example 2 in Examples.

FIG. 5 is an infrared absorption spectrum of a carbazole-based polymer according to Polymer Synthesis Example 1 in Examples.

FIG. 6 is an infrared absorption spectrum of a carbazole-based polymer according to Polymer Synthesis Example 2 in Examples.

FIG. 7 is a nuclear magnetic resonance spectrum of a carbazole-based polymer according to Polymer Synthesis Example 2 in Examples.

FIG. 8 is an infrared absorption spectrum of a carbazole-based polymer according to Polymer Synthesis Example 3 in Examples.

FIG. 9 is an infrared absorption spectrum of a carbazole-based polymer according to Polymer Synthesis Example 4 in Examples.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 33/14 C08L 33/14 39/04 39/04 G03G 5/07 102 G03G 5/07 102 H05B 33 / 14 H05B 33/14 A 33/22 33/22 D (72) Inventor Yasunori Negoro 2-11-24 Tsukiji, Chuo-ku, Tokyo FSR term in JSR Corporation (reference) 2H068 AA20 AA21 BA64 BB45 BB47 GA13 3K007 AB03 CA01 CB01 FA01 4C204 BB03 BB09 CB25 DB31 EB03 FB04 FB09 FB10 FB20 GB32 4J002 BJ001 BJ002 GQ00 4J100 AB07P AB07Q AL08P AM21P AQ26P AQ26Q BA02Q BA31P BA31Q BA37P BC43P BC43Q BC44Q JA65P

Claims (5)

[Claims] 1. A carbazole represented by the following general formula (1):
Derivatives. Embedded image[Wherein, R¹Is a hydrogen atom, an alkyl group or a phenyl group
And R^Two, R^Three, R ^FourAnd R^FiveAre independent
To hydrogen, alkyl, alkoxy, phenyl, etc.
Or a dialkylamino group. X is a single bond or
Is a phenylene group, a carbonyl group or one of them
Or a divalent organic group containing both. ] 2. A structural unit represented by the following general formula (2):
A carbazole-based polymer characterized by having: Embedded image[Wherein, R¹Is a hydrogen atom, an alkyl group or a phenyl group
And R^Two, R^Three, R ^FourAnd R^FiveAre independent
To hydrogen, alkyl, alkoxy, phenyl, etc.
Or a dialkylamino group. X is a single bond or
Is a phenylene group, a carbonyl group or one of them
Or a divalent organic group containing both. ] 3. The carbazole-based polymer according to claim 2, comprising 5% by mass or more of the structural unit represented by the general formula (2). 4. A hole transport material comprising the carbazole-based polymer according to claim 2 or 3. 5. A hole transport material comprising the carbazole polymer according to claim 2 or 3 and a polymer other than the carbazole polymer, wherein the hole transport material is a total polymer. Wherein the proportion of the structural unit represented by the general formula (2) is 5% by mass or more.