TWI614249B - Charge transport varnish, charge transporting film and organic electroluminescent element - Google Patents

Abstract

The present invention provides a charge-transporting varnish, a charge-transporting film, and an organic EL element that provide a film capable of achieving excellent brightness characteristics when applied to a hole injection layer of an organic EL element.

The charge-transporting varnish of the present invention is characterized by containing a charge-transporting substance composed of a thiophene derivative represented by formula (1), a dopant, and an organic solvent.

(Wherein R ¹ to R ²¹ each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, an aldehyde group, a hydroxyl group, a thiol group, a carboxylic acid group, an alkyl group, an alkenyl group, an alkynyl group, and a carbon number of 6 to 20 aryl group, -C (O) Y ¹ group, -OY ² group, -SY ³ group, -C (O) OY ⁴ group, -OC (O) Y ⁵ group, -C (O) NHY ⁶ group Or -C (O) NY ⁷ Y ⁸ base.)

Description

Charge-transporting varnish, charge-transporting film, and organic electroluminescent device

The present invention relates to a charge-transporting varnish, a charge-transporting film, and an organic electroluminescence (hereinafter referred to as an organic EL) element.

In the organic EL device, a charge-transporting thin film made of an organic compound can be used as a light-emitting layer or a charge-injection layer. In particular, the hole injection layer serves as the transfer of charge between the anode and the hole transporting layer or the light emitting layer, and achieves low voltage driving and high brightness of the organic EL element, and has important functions.

The formation method of the hole injection layer can be roughly divided into a dry process represented by the evaporation method and a wet process represented by the spin coating method. Compared to these processes, the wet process can efficiently produce a large area. High flatness film. Therefore, with the development of large-scale organic EL displays, a hole injection layer that can be formed by a wet process is expected.

In view of this situation, the present inventors have developed a charge-transporting material or a thin-film charge-transporting material that can be applied to various wet processes and also provides a hole injection layer suitable for an organic EL element, which can achieve excellent EL element characteristics. Compounds with good solubility in organic solvents for this material (See, for example, Patent Documents 1 to 4).

[Prior technical literature] [Patent Literature]

[Patent Document 1] International Publication No. 2008/032616

[Patent Document 2] International Publication No. 2008/129947

[Patent Document 3] International Publication No. 2006/025342

[Patent Document 4] International Publication No. 2010/058777

[Invention Summary]

The present invention is the same as the technology of the above-mentioned patent documents developed in the past, and an object of the present invention is to provide a charge-transporting varnish that imparts a thin film capable of achieving excellent characteristics when applied to a hole injection layer of an organic EL element.

In order to achieve the above-mentioned object, the present inventors have conducted careful research and found that a thin film obtained from a varnish containing a charge-transporting substance composed of a specific thiophene derivative, a dopant, and an organic solvent has high charge-transporting properties, and the film is suitable In the hole injection layer of the organic EL element, excellent brightness characteristics and excellent durability can be achieved, and the present invention has been completed.

That is, the present invention provides the following charge-transporting varnish, charge-transporting film, and organic EL device.

A charge-transporting varnish comprising a charge-transporting substance, a dopant, and an organic solvent composed of a thiophene derivative represented by formula (1).

(式中，R¹~R²¹各自獨立表示氫原子、鹵素原子、硝基、氰基、醛基、羥基、硫醇基、羧酸基、可經Z¹取代之碳數1~20之烷基、可經Z¹取代之碳數2~20之烯基、可經Z¹取代之碳數2~20之炔基、可經Z²取代之碳數6~20之芳基、-C(O)Y¹基、-OY²基、-SY³基、-C(O)OY⁴基、-OC(O)Y⁵基、-C(O)NHY⁶基或-C(O)NY⁷Y⁸基，Y¹~Y⁸各自獨立表示可經Z¹取代之碳數1~20之烷基、可經Z¹取代之碳數2~20之烯基、可經Z¹取代之碳數2~20之炔基或可經Z²取代之碳數6~20之芳基，Z¹表示鹵素原子、硝基、氰基、醛基、羥基、硫醇基、磺酸基、羧酸基或可經Z³取代之碳數6~20之芳基，Z²表示鹵素原子、硝基、氰基、醛基、羥基、硫醇基、磺酸基、羧酸基、可經Z³取代之碳數1~20之烷基、 可經Z³取代之碳數2~20之烯基或可經Z³取代之碳數2~20之炔基，Z³表示鹵素原子、硝基、氰基、醛基、羥基、硫醇基、磺酸基或羧酸基，n¹~n³各自獨立表示2~10之整數)。

(Wherein R ¹ to R ²¹ each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, an aldehyde group, a hydroxyl group, a thiol group, a carboxylic acid group, and an alkane having 1 to 20 carbon atoms which may be substituted by Z ¹ group, may be substituted with Z ¹ of the carbon atoms of the alkenyl group having 2 to 20, Z ¹ may be substituted with an alkynyl group of a carbon number of 2 to 20, Z ² may be substituted having 6 to 20 carbon atoms of the aryl group, -C ( O) Y ¹ group, -OY ² group, -SY ³ group, -C (O) OY ⁴ group, -OC (O) Y ⁵ group, -C (O) NHY ⁶ group, or -C (O) NY ⁷ group Y ^8, Y ¹ ~ Y ⁸ each independently represent Z ¹ may be substituted having 1 to 20 carbon atoms of the alkyl group, may be substituted with Z ¹ of the carbon atoms of the alkenyl group having 2 to 20, Z ¹ may be substituted with a carbon number of An alkynyl group of 2 to 20 or an aryl group of 6 to 20 carbon atoms that can be substituted by Z ² ; Z ¹ represents a halogen atom, a nitro group, a cyano group, an aldehyde group, a hydroxyl group, a thiol group, a sulfonic acid group, and a carboxylic acid group Or an aryl group having 6 to 20 carbon atoms which may be substituted by Z ³ , Z ² represents a halogen atom, a nitro group, a cyano group, an aldehyde group, a hydroxyl group, a thiol group, a sulfonic acid group, a carboxylic acid group, and may be substituted by Z ³ Alkyl group having 1 to 20 carbon atoms, alkenyl group having 2 to 20 carbon atoms which can be substituted with Z ³ or alkynyl group having 2 to 20 carbon atoms which can be substituted with Z ³ , Z ³ represents a halogen atom, a nitro group, a cyanide Group, aldehyde group, hydroxyl group, thiol group, sulfone Group or a carboxylic acid group, n ¹ ~ n ³ each independently represents an integer of from 2 to 10).

2. The charge-transporting varnish according to the aforementioned item 1, wherein the dopant contains a heteropolyacid.

3. The charge-transporting varnish according to item 1 or 2 above, further comprising an organosilane compound.

(式中，R¹⁰¹~R¹⁰⁴各自獨立表示氫原子或鹵素原子，但至少1個為鹵素原子)。 4. The charge-transporting varnish according to any one of items 1 to 3 above, which further comprises a tetracyanobenzoquinone dimethane compound represented by the following formula (6),

(In the formula, R ¹⁰¹ to R ¹⁰⁴ each independently represent a hydrogen atom or a halogen atom, but at least one is a halogen atom.)

5. A charge-transporting film characterized by using the charge-transporting varnish according to any one of items 1 to 4 above.

6. An organic electroluminescence device, comprising the charge-transporting film according to item 5 above.

7. The organic electroluminescent device according to the aforementioned item 6, wherein the charge transporting film is a hole injection layer or a hole transport layer.

8. A method for manufacturing a charge-transporting film, characterized in that the charge-transporting varnish according to any one of the foregoing items 1 to 4 is applied to a substrate Burners.

9. A method for manufacturing an organic electroluminescence device, characterized by using the charge-transporting film as described in item 4 above.

(式中，R¹~R²¹各自獨立表示氫原子、鹵素原子、硝基、氰基、醛基、羥基、硫醇基、羧酸基、可經Z¹取代之碳數1~20之烷基、可經Z¹取代之碳數2~20之烯基、可經Z¹取代之碳數2~20之炔基、可經Z²取代之碳數6~20之芳基、-C(O)Y¹基、-OY²基、-SY³基、-C(O)OY⁴基、-OC(O)Y⁵基、-C(O)NHY⁶基或-C(O)NY⁷Y⁸基，Y¹~Y⁸各自獨立表示可經Z¹取代之碳數1~20之烷基、可經Z¹取代之碳數2~20之烯基、可經Z¹取代之碳數2~20之炔基或可經Z²取代之碳數6~20之芳基，Z¹表示鹵素原子、硝基、氰基、醛基、羥基、硫醇基、磺酸基、羧酸基或可經Z³取代之碳數6~20之芳基，Z²表示鹵素原子、硝基、氰基、醛基、羥基、硫醇基、磺酸基、羧酸基、可經Z³取代之碳數1~20之烷基、 可經Z³取代之碳數2~20之烯基或可經Z³取代之碳數2~20之炔基，Z³表示鹵素原子、硝基、氰基、醛基、羥基、硫醇基、磺酸基或羧酸基，n¹~n³各自獨立表示2~10之整數)。 10. A charge-transporting material characterized by containing a charge-transporting substance and a dopant composed of a thiophene derivative represented by formula (1),

(Wherein R ¹ to R ²¹ each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, an aldehyde group, a hydroxyl group, a thiol group, a carboxylic acid group, and an alkane having 1 to 20 carbon atoms which may be substituted by Z ¹ group, may be substituted with Z ¹ of the carbon atoms of the alkenyl group having 2 to 20, Z ¹ may be substituted with an alkynyl group of a carbon number of 2 to 20, Z ² may be substituted having 6 to 20 carbon atoms of the aryl group, -C ( O) Y ¹ group, -OY ² group, -SY ³ group, -C (O) OY ⁴ group, -OC (O) Y ⁵ group, -C (O) NHY ⁶ group, or -C (O) NY ⁷ group Y ^8, Y ¹ ~ Y ⁸ each independently represent Z ¹ may be substituted having 1 to 20 carbon atoms of the alkyl group, may be substituted with Z ¹ of the carbon atoms of the alkenyl group having 2 to 20, Z ¹ may be substituted with a carbon number of An alkynyl group of 2 to 20 or an aryl group of 6 to 20 carbon atoms that can be substituted by Z ² ; Z ¹ represents a halogen atom, a nitro group, a cyano group, an aldehyde group, a hydroxyl group, a thiol group, a sulfonic acid group, and a carboxylic acid group Or an aryl group having 6 to 20 carbon atoms which may be substituted by Z ³ , Z ² represents a halogen atom, a nitro group, a cyano group, an aldehyde group, a hydroxyl group, a thiol group, a sulfonic acid group, a carboxylic acid group, and may be substituted by Z ³ Alkyl group having 1 to 20 carbon atoms, alkenyl group having 2 to 20 carbon atoms which can be substituted with Z ³ or alkynyl group having 2 to 20 carbon atoms which can be substituted with Z ³ , Z ³ represents a halogen atom, a nitro group, a cyanide Group, aldehyde group, hydroxyl group, thiol group, sulfone Group or a carboxylic acid group, n ¹ ~ n ³ each independently represents an integer of from 2 to 10).

The thiophene derivative used in the present invention is easily soluble in an organic solvent, and the thiophene derivative is dissolved in an organic solvent together with the dopant, and the charge-transporting varnish can be easily prepared.

Since the thin film produced from the charge-transporting varnish of the present invention exhibits high charge-transporting properties, it can be applied to films for electronic devices including organic EL elements. In particular, this film is suitable for a hole injection layer of an organic EL element, and an organic EL element having excellent brightness characteristics and durability can be obtained.

In addition, since the charge-transporting varnish of the present invention contains an organic silane compound or a tetracyanobenzoquinone dimethane compound, it can be fired at a lower temperature than in the past. The film produced at this time has high flatness and high charge-transportability.

In addition, the charge-transporting varnish of the present invention has good reproducibility and produces a film having excellent charge-transportability even when various wet processes capable of forming a large area are formed using a spin coating method, a slit coating method, or the like. , Can also fully respond to the recent progress in the field of organic EL elements.

In addition, the film obtained from the charge-transporting varnish of the present invention can also be used as an antistatic film or an anode buffer layer for an organic thin-film solar cell. use.

[Mode for Carrying Out the Invention] [Charge-transporting substance]

The charge-transporting varnish of the present invention contains a charge-transporting substance composed of a thiophene derivative represented by the following formula (1).

In the present invention, the charge transportability is synonymous with conductivity and synonymous with hole transportability. The charge-transporting substance may be a substance having a charge-transporting property in itself or a substance having a charge-transporting property when used with an electron-accepting substance. The charge-transporting varnish may be one having a charge-transporting property by itself, or a solid film obtained by using the charge-transporting varnish.

R ¹ to R ²¹ each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, an aldehyde group, a hydroxyl group, a thiol group, a carboxylic acid group, an alkyl group having 1 to 20 carbon atoms which may be substituted by Z ¹ , Z ¹ substituted alkenyl group with 2 to 20 carbon atoms, Z ¹ substituted carbon group with 2 to 20 alkynyl group, Z ² substituted carbon group with 6 to 20 aryl group, -C (O) Y ¹ Group, -OY ² group, -SY ³ group, -C (O) OY ⁴ group, -OC (O) Y ⁵ group, -C (O) NHY ⁶ group, or -C (O) NY ⁷ Y ⁸ group.

Y ¹ ~ Y ⁸ each independently represent an alkyl group may be substituted with Z ¹ of the carbon atoms of 1 to 20, Z ¹ may be substituted with the carbon atoms of the alkenyl group having 2 to 20, may be substituted with Z ¹ of the 2 to 20 carbon atoms Alkynyl or aryl having 6 to 20 carbon atoms which may be substituted by Z ² .

Z ¹ represents a halogen atom, a nitro group, a cyano group, an aldehyde group, a hydroxyl group, a thiol group, a sulfonic acid group, a carboxylic acid group, or an aryl group having 6 to 20 carbon atoms which may be substituted by Z ³ .

Z ² represents a halogen atom, a nitro group, a cyano group, an aldehyde group, a hydroxyl group, a thiol group, a sulfonic acid group, a carboxylic acid group, Z ³ may be substituted with an alkyl group of 1 to 20 carbon atoms, the substituent of Z ³ may be Alkenyl group having 2 to 20 carbon atoms or alkynyl group having 2 to 20 carbon atoms which can be substituted by Z ³ .

Z ³ represents a halogen atom, a nitro group, a cyano group, an aldehyde group, a hydroxyl group, a thiol group, a sulfonic acid group, or a carboxylic acid group.

n ¹ to n ³ each independently represent an integer of 2 to 10.

Examples of the halogen atom include fluorine, chlorine, bromine, and iodine atoms.

The alkyl group having 1 to 20 carbon atoms may be linear, branched, or cyclic. Examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, and iso. Butyl, s-butyl, t-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, etc. Chain or branched chain alkyl; cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, bicyclobutyl, dicyclopentyl, dicyclohexyl, Bicycloheptyl, bicyclooctyl, bicyclononyl, bicyclodecyl, and the like having a cyclic alkyl group having 3 to 20 carbon atoms.

Specific examples of alkenyl groups having 2 to 20 carbon atoms, for example: ethylene Group, n-1-propenyl, n-2-propenyl, 1-methylvinyl, n-1-butenyl, n-2-butenyl, n-3-butenyl, 2-methyl 1-propenyl, 2-methyl-2-propenyl, 1-ethylvinyl, 1-methyl-1-propenyl, 1-methyl-2-propenyl, n-1-pentene , N-1-decenyl, n-1-icosenyl, and the like.

Specific examples of the alkynyl group having 2 to 20 carbon atoms include ethynyl, n-1-propynyl, n-2-propynyl, n-1-butynyl, n-2-butynyl, n-3-butynyl, 1-methyl-2-propynyl, n-1-pentynyl, n-2-pentynyl, n-3-pentynyl, n-4-pentynyl , 1-methyl-n-butynyl, 2-methyl-n-butynyl, 3-methyl-n-butynyl, 1,1-dimethyl-n-propynyl, n- 1-hexynyl, n-1-decynyl, n-1-pentadeynyl, n-1-icosynyl and the like.

Specific examples of aryl groups having 6 to 20 carbon atoms include phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2- Fickey, 3-Ficky, 4-Ficky, 9-Ficky, etc.

R ¹ to R ^{21 are} preferably a hydrogen atom or an alkyl group having 1 to 20 carbon atoms which may be substituted by Z ¹ , and most preferably a hydrogen atom.

When R ¹ to R ²¹ and Y ¹ to Y ⁸ are an alkyl group, an alkenyl group, an alkynyl group, or an aryl group, Z ^{1 is} preferably a halogen atom or an aryl group having 6 to 20 carbon atoms which may be substituted by Z ³ . More preferred is phenyl which may be substituted by Z ³ , and most preferred is absent (ie, non-substituted).

Z ² is preferably a halogen atom or an alkyl group substituted by Z ³ of the carbon atoms of 1 to 20, more preferably a carbon number of Z ³ may be substituted with the alkyl group of 1 to 10, and more preferably may be substituted with Z ³ An alkyl group having 1 to 8 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms which can be substituted by Z ³ , is most preferably absent (ie, non-substituted).

Z ^{3 is} preferably a halogen atom, more preferably fluorine, and most preferably non-existent (ie, non-substituted).

Specific examples of the thiophene derivative represented by the formula (1) are listed below, but are not limited thereto.

[Production method of thiophene derivative]

The thiophene derivative used in the present invention can be synthesized according to methods described in, for example, Tetrahedron Letters, 2010, 51 (50), pp. 6673-6676, JP 2003-167972, and the like, but is not limited thereto.

Specifically, for example, triphenylamine or its derivative and thiophene or its derivative are used as starting materials. Coupling, Rightfield, Kosugi, Stille Coupling, Negishi coupling, Suzuki ‧Synthesis by coupling reaction of Miyaura coupling, Laoshan coupling, etc.

For example, triphenylamine or a derivative thereof represented by the formula (2) is subjected to halogenation or stylization, etc. In order to make a cross-coupling reaction with this, the formulae (3) to (5) are represented The thiophene derivative may be subjected to tinization or the like, or halogenated, and the coupling reaction may be performed.

(式中，R¹~R²¹及n¹~n³係與上述相同。)

(In the formula, R ¹ to R ²¹ and n ¹ to n ³ are the same as above.)

At this time, the input ratio of the thiophene or its derivative represented by the formulas (3) to (5) is generally about 0.5 to 1.5 equivalents relative to the triphenylamine or its derivative represented by the formula (2), respectively. It is about 0.9 ~ 1.3 equivalent.

The compounds represented by the formulae (2) to (5) may be commercially available products, or they may be synthesized by conventional methods.

[Dopant]

The charge-transporting varnish of the present invention contains a dopant. The dopant is not particularly limited, and either an organic dopant or an inorganic dopant can be used.

Among them, in the best aspect, the charge-transporting varnish of the present invention contains a heteropoly acid as a dopant, and therefore, it is possible to obtain not only the transparency represented by indium tin oxide (ITO), indium zinc oxide (IZO), etc. A thin film having high hole-receiving energy of an electrode and excellent charge-transporting property of high hole-receiving energy of a metal anode represented by aluminum.

Heteropoly acid refers to the chemical structure represented by the Keggin type represented by the formula (A1) or the Dawson type represented by the formula (A2). A structure in which a heteroatom is located at the center of the molecule, and oxoacid, isopoly acid, and polyoxo acid of different elements Polyacid obtained by condensation. The oxyacids of such heterogeneous elements include, for example, oxyacids of silicon (Si), phosphorus (P), and arsenic (As).

Specific examples of the heteropoly acid include, for example, phosphomolybdic acid, silomomolybdic acid, phosphotungstic acid, silototungstic acid, phosphotungstic molybdic acid, and the like. These can be used alone or in combination of two or more. The heteropolyacid used in the present invention can be obtained from a commercially available product, and can also be synthesized by a conventional method.

In particular, when the dopant is composed of one type of heteropoly acid, the one type of heteropoly acid is preferably phosphotungstic acid or phosphomolybdic acid, and more preferably phosphotungstic acid. When the dopant is composed of two or more types of heteropolyacid, at least one of the two or more types of heteropolyacid is preferably phosphotungstic acid or phosphomolybdic acid, and more preferably phosphotungstic acid.

In addition, the heteropolyacid has a structure represented by a general formula in quantitative analysis such as elemental analysis, and even if the number of elements is large or small, as long as it is obtained from a commercially available product or appropriately synthesized according to a conventional synthesis method In either case, it can be used in the present invention.

That is, for example, the general phosphotungstic acid is represented by the chemical formula H ₃ (PW ₁₂ O ₄₀ ) ‧nH ₂ O, and the phosphomolybdic acid is represented by the chemical formula H ₃ (PMo ₁₂ O ₄₀ ) ‧nH ₂ O, but in the quantitative analysis , Even if the amount of P (phosphorus), O (oxygen), W (tungsten), or Mo (molybdenum) in this formula is more or less, as long as it is obtained from a commercially available product, or according to a conventional synthesis method, it is appropriate All synthesizers can be used in the present invention. At this time, the mass of the heteropolyacid specified in the present invention does not refer to the mass of pure phosphotungstic acid (phosphotungstic acid content) in the composition or the commercially available product, but refers to the form and commercially available product. In the form that can be separated by the conventional synthesis method, it contains the full mass of hydrated water or other impurities.

The heteropoly acid contained in the charge-transporting varnish of the present invention is expressed by mass ratio, and can be set to about 1.0 to 70.0, preferably about 2.0 to 60.0, and more preferably about 2.5 to 55.0 relative to the charge transporting substance 1. , And more preferably about 2.5 ~ 25.0.

[Organic solvents]

As the organic solvent used in the preparation of the charge-transporting varnish, a highly soluble solvent that can well dissolve the charge-transporting substance and the dopant can be used.

As such a highly soluble solvent, for example, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, 1,3-dimethyl-2-imidazoline can be used. Organic solvents such as ketones. These solvents can be used singly or in combination of two or more kinds. The amount of the solvent used is 5 to 100% by mass based on the entire solvent used in the varnish.

Moreover, it is preferable that both the charge transporting substance and the dopant are completely dissolved in the solvent.

In the present invention, the varnish contains at least one kind of varnish having a viscosity of 10 to 200 mPa · s, especially 35 to 150 mPa · s at 25 ° C, and a boiling point of 50 to 300 ° C at normal pressure (atmospheric pressure). In particular, a high-viscosity organic solvent at 150 to 250 ° C makes it easy to adjust the viscosity of the varnish. As a result, it has good reproducibility and provides a film with high flatness. The varnish can be prepared according to the coating method used.

The high-viscosity organic solvent is not particularly limited, and examples thereof include cyclohexanol, ethylene glycol, ethylene glycol diglycidyl ether, 1,3-octanediol, diethylene glycol, dipropylene glycol, triethylene glycol, and tripropylene glycol. , 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, propylene glycol, hexanediol, and the like. These solvents can be used singly or in combination of two or more.

The addition ratio of the high-viscosity organic solvent to the entire solvent used in the varnish of the present invention is preferably in a range where solids do not precipitate, and in a range where solids do not precipitate, the addition ratio is preferably 5 to 80% by mass.

In addition, in order to improve the wettability of the substrate, adjust the surface tension of the solvent, adjust the polarity, and adjust the boiling point, etc., it is preferable to mix 1 to 90% by mass, and more preferably to mix 1 to the entire solvent used in the varnish. 50% by mass of other solvents.

Examples of such a solvent include ethylene glycol monobutyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, and diethylene glycol monoethyl ether acetate. , Diethylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether, diacetone alcohol, γ-butyrolactone, ethyl Lactate, n-hexyl acetate, diethylene glycol monomethyl ether, and the like, but are not limited thereto. These solvents can be used alone or Use by mixing 2 or more types.

The viscosity of the varnish of the present invention is suitable for the thickness of the film to be produced or the solid content concentration, but it is usually 1 to 50 mPa · s at 25 ° C.

The solid content concentration of the charge-transporting varnish in the present invention is appropriately set in consideration of the viscosity and surface tension of the varnish or the thickness of the film to be produced, but it is usually about 0.1 to 10.0% by mass. In the case of coatability, it is preferably 0.5 to 5.0% by mass, and more preferably 1.0 to 3.0% by mass.

[Organic Silane Compound]

The charge-transporting varnish of the present invention preferably contains an organic silane compound. The organic silane compound is, for example, a dialkoxysilane compound, a trialkoxysilane compound, or a tetraalkoxysilane compound. These can be used individually by 1 type or in combination of 2 or more types.

In particular, the organic silane compound preferably contains one selected from a dialkoxysilane compound and a trialkoxysilane compound, and more preferably contains a trialkoxysilane compound.

Examples of the dialkoxysilane compound, trialkoxysilane compound, and tetraalkoxysilane compound include formulas (B1) to (B3).

SiR ' ₂ (OR) ₂ (B1)

SiR '(OR) ₃ (B2)

Si (OR) ₄ (B3)

In the formula, R each independently represents an alkyl group may be substituted with Z ¹⁰¹ carbon atoms of 1 to 20, the sum may be substituted with Z ¹⁰¹ carbon atoms, alkenyl having 2 to 20, the sum may be substituted with Z ¹⁰¹ carbon atoms, alkynyl of 2 to 20 Group, an aryl group having 6 to 20 carbon atoms which may be substituted by Z ¹⁰² or a heteroaryl group having 2 to 20 carbon atoms which may be substituted by Z ¹⁰² . R 'each independently represent an alkyl group may be substituted with Z 1 of ¹⁰³ to 20 carbon atoms, the substituents Z may be the ¹⁰³ carbon atoms of the alkenyl group having 2 to 20, Z may be a substituted alkynyl group of ¹⁰³ carbon atoms of 2 to 20, the heteroaryl may be 2 to 20 substituted aryl group of Z ¹⁰⁴ carbon atoms, an aryl group of 6 to 20 may be substituted with Z ¹⁰⁴ or the number of carbon atoms.

Z ¹⁰¹ represents a halogen atom, an aryl group having 6 to 20 carbon atoms which may be substituted with Z ¹⁰⁵ or a heteroaryl group having 2 to 20 carbon atoms which may be substituted with Z ¹⁰⁵ .

Z ¹⁰² represents a halogen atom, an alkyl group may be substituted by Z ¹⁰⁵ of 1 to 20 carbon atoms, the sum may be substituted with Z ¹⁰⁵ carbon atoms of the alkenyl group having 2 to 20 or ¹⁰⁵ may be substituted with Z alkynyl of 2 to 20 carbon atoms of the group .

Z ¹⁰³ represents a halogen atom, an aryl group having 6 to 20 carbon atoms which can be substituted by Z ¹⁰⁵ , a heteroaryl group having 2 to 20 carbon atoms which can be substituted by Z ¹⁰⁵ , epoxycyclohexyl, glycidyloxy, methyl Propylene fluorenyloxy, propylene fluorenyloxy, ureido (-NHCONH ₂ ), thiol, isocyanate (-NCO), amine, -NHY ¹⁰¹ or -NY ¹⁰² Y ¹⁰³ .

Z ¹⁰⁴ represents a halogen atom, an alkyl group may be substituted with Z ¹⁰⁵ of 1 to 20 carbon atoms, the substituents Z may be the ¹⁰⁵ carbon atoms of the alkenyl group having 2 to 20, Z ¹⁰⁵ may be substituted alkynyl of 2 to 20 carbon atoms of the group , Epoxycyclohexyl, glycidyloxy, methacryloxy, propyleneoxy, ureido (-NHCONH ₂ ), thiol, isocyanate (-NCO), amine, -NHY ¹⁰¹ Base or -NY ¹⁰² Y ¹⁰³ base.

Y ¹⁰¹ ~ Y ¹⁰³ each independently represent an alkyl group may be substituted with Z ¹⁰⁵ of 1 to 20 carbon atoms, the sum may be substituted with Z ¹⁰⁵ carbon atoms of the alkenyl group having 2 to 20, carbon atoms can be substituted by Z 2 to 20 of the ¹⁰⁵ alkynyl group, Z ¹⁰⁵ may be a substituted aryl group of a carbon number of 6 to 20 aryl or heteroaryl group substituted by Z ¹⁰⁵ of the 2 to 20 carbon atoms.

Z ¹⁰⁵ represents a halogen atom, an amine group, a nitro group, a cyano group, or a thiol group.

Halogen atoms in formulas (B1) to (B3), alkyl groups having 1 to 20 carbon atoms, alkenyl groups having 2 to 20 carbon atoms, alkynyl groups having 2 to 20 carbon atoms, and aryl groups having 6 to 20 carbon atoms, for example There are the same as above.

R is preferably an alkyl group may be substituted by the Z ¹⁰¹ of 1 to 20 carbon atoms, may be substituted with the group Z ¹⁰¹ carbon atoms, alkenyl of 2 to 20, or it may be substituted with Z ¹⁰² carbon atoms of the aryl group having 6 to 20, more Jia Z ¹⁰¹ is substituted it may be an alkyl group having 1 to 6 carbon atoms, the substituents may be the Z ¹⁰¹ carbon atoms of the alkenyl group having 2 to 6 or, more preferably and Z ¹⁰¹ may be substituted by a substituted phenyl group of Z ¹⁰² An alkyl group having 1 to 4 carbon atoms or a phenyl group which may be substituted with Z ¹⁰² , and more preferably a methyl group or ethyl group which may be substituted with Z ¹⁰¹ .

Further, R ′ is preferably an alkyl group having 1 to 20 carbon atoms that can be substituted by Z ¹⁰³ or an aryl group having 6 to 20 carbon atoms that can be substituted by Z ¹⁰⁴ , and more preferably 1 to 20 carbon atoms that can be substituted by Z ¹⁰³ . An alkyl group of 10 or an aryl group having 6 to 14 carbon atoms that can be substituted by Z ¹⁰⁴ , and an alkyl group of 1 to 6 carbon atoms that can be substituted by Z ¹⁰³ or 6 to 10 carbon atoms that can be substituted by Z ¹⁰⁴ The aryl group is more preferably an alkyl group having 1 to 4 carbon atoms which may be substituted by Z ¹⁰³ or a phenyl group which may be substituted by Z ¹⁰⁴ .

Moreover, all of the plural R's may be the same or different, and all of the plural R's may be the same or different.

Z ^{101 is} preferably a halogen atom or an aryl group having 6 to 20 carbon atoms which can be substituted by Z ¹⁰⁵ , more preferably a fluorine atom or a phenyl group which can be substituted by Z ¹⁰⁵ , and most preferably is absent (ie, non-substituted).

In addition, Z ^{102 is} preferably a halogen atom or an alkyl group having 6 to 20 carbon atoms which may be substituted with Z ¹⁰⁵ , more preferably a fluorine atom or an alkyl group having 1 to 10 carbon atoms which may be substituted with Z ¹⁰⁵ , and most preferably not Exists (ie, non-substituted).

Further, Z ¹⁰³ is preferably a halogen atom, a phenyl group may be substituted by Z of ^{105, 105} may be substituted with Z of furanyl, epoxy cyclohexyl group, glycidoxy group, Bing Xixi methyl group, an oxygen Bing Xixi Group, urea group, thiol group, isocyanate group, amine group, phenylamino group which can be substituted by Z ¹⁰⁵ or diphenylamino group which can be substituted by Z ¹⁰⁴ , more preferably a halogen atom, and more preferably a fluorine atom Or does not exist (ie, non-substituted).

And, Z ¹⁰⁴ is preferably a halogen atom, an alkyl group may be substituted by Z ¹⁰⁵ of 1 to 20 carbon atoms, the substituents Z may be the ¹⁰⁵ furanyl, epoxy cyclohexyl group, glycidoxy group, methyl Bing Xixi group, Bing Xixi group, a ureido group, a thiol group, isocyanate group, amino group, Z may be a substituted phenyl group of ¹⁰⁵ or ¹⁰⁵ may be substituted with Z bis phenyl group, more preferably a halogen atom, Still more preferably, a fluorine atom is absent (ie, non-substituted).

Further, Z ^{105 is} preferably a halogen atom, more preferably a fluorine atom or is absent (ie, non-substituted).

Specific examples of the organosilane compound that can be used in the present invention are listed below, but are not limited thereto.

Specific examples of the dialkoxysilane compound include dimethyldimethoxysilane, dimethyldiethoxysilane, methylethyldimethoxysilane, diethyldimethoxysilane, Diethyldiethoxysilane, methylpropyldimethoxysilane, methylpropyldiethoxysilane, diisopropyldimethyl Oxysilane, phenylmethyldimethoxysilane, vinylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyl Methyldiethoxysilane, 3- (3,4-epoxycyclohexyl) ethylmethyldimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3 -Methacryloxypropylmethyldiethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, N- (2-amine Ethyl) aminopropylmethyldimethoxysilane, 3,3,3-trifluoropropylmethyldimethoxysilane and the like.

Specific examples of the trialkoxysilane compound include, for example, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, Propyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, pentyltrimethoxysilane, pentyltriethoxysilane, heptyltrimethoxysilane, heptyltriethoxy Silane, octyltrimethoxysilane, octyltriethoxysilane, dodecyltrimethoxysilane, dodecyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethyl Oxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxy Silane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltrisiloxane Ethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, (4- (trifluoromethyl) phenyl) silane, dodecyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, (triethoxysilane) ring Hexane, perfluoro Octylethyltriethoxysilane, triethoxyfluorosilane, tridecyl-1,1,2,2-tetrahydrooctyltriethoxysilane, pentafluorophenyltrimethoxysilane, pentafluoro Phenyltriethoxysilane, 3- (heptafluoroisopropoxy) propyltriethoxysilane, heptafluoro-1,1,2,2-tetrahydrodecyltriethoxysilane, triethyl Oxy-2-thienylsilane, 3- (triethoxysilyl) furan, and the like.

Specific examples of the tetraalkoxysilane compound include tetramethoxysilane, tetraethoxysilane, and tetrapropoxysilane.

Among these, 3,3,3-trifluoropropylmethyldimethoxysilane, triethoxy (4- (trifluoromethyl) phenyl) silane, and 3,3,3- Trifluoropropyltrimethoxysilane, perfluorooctylethyltriethoxysilane, pentafluorophenyltrimethoxysilane, pentafluorophenyltriethoxysilane, etc.

The content of the organosilane compound in the charge-transporting varnish of the present invention is generally about 0.1 to 50% by mass relative to the total mass of the charge-transporting substance and the dopant, but if consideration is given to suppressing the charge-transportability of the obtained film When it is lowered and the hole injection energy of the layer laminated on the opposite side of the anode such as the hole transport layer or the light emitting layer by contacting the hole injection layer is improved, it is preferably about 0.5 to 40% by mass. It is preferably about 0.8 to 30% by mass, and even more preferably about 1 to 20% by mass.

[Tetracyanobenzoquinone dimethane compound]

The charge-transporting varnish of the present invention preferably contains a tetracyanoquinodimethane compound represented by formula (6). When the obtained thin film is used as a hole injection layer of an organic EL device by containing a tetracyanobenzoquinone dimethane compound, the brightness is further improved. And other characteristics. In addition, when the varnish is fired at a low temperature, a film having high flatness and high charge transportability can be produced with good reproducibility.

In the formula, R ¹⁰¹ to R ¹⁰⁴ each independently represent a hydrogen atom or a halogen atom, but at least one of them is a halogen atom. The halogen atom is, for example, the same as described above, preferably a fluorine atom or a chlorine atom, and more preferably a fluorine atom. In addition, at least two of R ¹⁰¹ to R ¹⁰⁴ are preferably halogen atoms, more preferably at least three are halogen atoms, and all of them are most preferably halogen atoms.

Specific examples of the tetracyanobenzoquinone dimethane compound include tetrafluorotetracyanobenzoquinone dimethane (F4TCNQ), tetrachlorotetracyanobenzoquinone dimethane, 2-fluorotetracyanobenzoquinone dimethane, 2 -Chlorotetracyanobenzoquinone dimethane, 2,5-difluorotetracyanobenzoquinone dimethane, 2,5-dichlorotetracyanobenzoquinone dimethane, and the like. Tetracyanobenzoquinone dimethane compound, particularly preferred is F4TCNQ.

The content of the tetracyanobenzoquinone dimethane compound in the charge-transporting varnish of the present invention is preferably 0.0001 to 1 equivalent, more preferably 0.001 to 0.5 equivalent, and still more preferably 0.01 to 0.2 equivalent with respect to the thiophene derivative. .

[Other ingredients]

The charge-transporting varnish of the present invention may contain other charge-transporting substances in addition to the above-mentioned thiophene derivative as long as the effect of the present invention is not impaired. The charge-transporting varnish of the present invention may contain other substances in place of the heteropoly acid as a dopant.

Examples of other charge-transporting substances include the oligoaniline derivatives described in Japanese Patent Application Laid-Open No. 2002-151272, the oligoaniline compounds described in International Publication No. 2004/105446, and the oligoaniline compounds described in International Publication No. 2005/043962. A compound of 1,4-dithiin ring, an oligoaniline compound described in International Publication No. 2008/032617, an oligoaniline compound described in International Publication No. 2008/032616, and International Publication No. 2013 / An aryldiamine compound described in No. 042623.

In particular, other charge-transporting substances are preferably aniline derivatives. When considering the solubility in organic solvents, the molecular weight is preferably 4,000 or less, more preferably 3,000 or less, and even more preferably 2,000 or less.

In the present invention, examples of the aniline derivative suitable for use as another charge transporting substance include those represented by formula (7).

B ¹ represents a single bond, -NH-, -CH _2- , -S-, or -O-, and is preferably a single bond or -NH-.

R ²⁰¹ ~ R ²⁰⁶ each independently represent a hydrogen atom, a halogen atom, an alkyl group may be substituted with Z ²⁰¹ carbon atoms of 1 to 20, Z ²⁰¹ may be substituted by an alkenyl group having a carbon number of 2 to 20, may be Z ²⁰¹ substituted alkynyl group having a carbon number of 2 to 20, Z ²⁰² may be substituted having 6 to 20 carbon atoms of the aryl group may be substituted with Z ²⁰² 2 to 20 carbon atoms of the hetero aryl group, -OY ²⁰¹ group, -SY ²⁰² group, -NHY ²⁰³ , -NY ²⁰⁴ Y ²⁰⁵ group, or -NHC (O) Y ²⁰⁶ group. Y ²⁰¹ ~ Y ²⁰⁶ each independently represent an alkyl group may be substituted with Z ²⁰¹ 1 to 20 of carbon atoms, may be substituted with Z ²⁰¹ carbon atoms of the alkenyl group having 2 to 20, Z ²⁰¹ may be replaced by 2 carbon atoms ~ 20 alkynyl group, the heteroatoms may be the aryl group having 2 to 20 substituted by Z ²⁰² carbon atoms, an aryl group of 6 to 20 or may be substituted with Z ²⁰² carbon atoms. Specific examples of such a halogen atom, an alkyl group, an alkenyl group, an alkenyl group, an aryl group, and a heteroaryl group may be the same as those described above.

Z ²⁰¹ represents a halogen atom, a nitro group, a cyano group, an aldehyde group, a hydroxyl group, a thiol group, a sulfonic acid group, a carboxylic acid group, may be substituted with Z ²⁰³ carbon atoms of an aryl group of 6 to 20 or Z ²⁰³ may be the Heteroaryl groups having 2 to 20 carbon atoms.

Z ²⁰² represents a halogen atom, a nitro group, a cyano group, an aldehyde group, a hydroxyl group, a thiol group, a sulfonic acid group, a carboxylic acid group, an alkyl group may be substituted by the Z ²⁰³ carbon atoms of 1 to 20, Z ²⁰³ may be the Alkenyl having 2 to 20 carbon atoms substituted or alkynyl having 2 to 20 carbon atoms substituted by Z ²⁰³ .

Z ²⁰³ represents a halogen atom, a nitro group, a cyano group, an aldehyde group, a hydroxyl group, a thiol group, a sulfonic acid group, or a carboxylic acid group.

R ²⁰¹ to R ^{204 are} preferably a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms that can be substituted by Z ²⁰¹ , an aryl group having 6 to 20 carbon atoms that can be substituted by Z ²⁰² , and Z ²⁰¹ The substituted alkoxy group having 1 to 20 carbons (that is, Y ²⁰¹ is a -OY ²⁰¹ group having 1 to 20 alkyl groups which can be substituted by Z ²⁰¹ ), more preferably a hydrogen atom, a fluorine atom, or Alkyl groups having 1 to 10 carbon atoms replaced by Z ²⁰¹ , aryl groups having 6 to 14 carbon atoms that can be replaced by Z ²⁰² , alkoxy groups 1 to 10 carbon atoms that can be replaced by Z ²⁰¹ , and more It is preferably a hydrogen atom, a fluorine atom, an alkyl group having 1 to 6 carbon atoms that can be replaced by Z ²⁰¹ , an aryl group having 6 to 10 carbon atoms that can be replaced by Z ²⁰² , and 1 to 6 carbon atoms that can be replaced by Z ²⁰¹ The alkoxy group is more preferably a hydrogen atom, a fluorine atom, an alkyl group having 1 to 6 carbon atoms which can be substituted by Z ²⁰¹ , and an alkoxy group having 1 to 6 carbon atoms which can be substituted by Z ²⁰¹ . Is a hydrogen atom.

In addition, R ²⁰⁵ and R ^{206 are} preferably a hydrogen atom, a halogen atom, and each alkyl group is a dialkylamino group having 1 to 20 carbon atoms which may be substituted by Z ²⁰¹ (ie, Y ²⁰⁴ and Y ²⁰⁵ (A group of -NY ²⁰⁴ Y ^{205 which is} an alkyl group having 1 to 20 carbon atoms which may be substituted by Z ²⁰¹ ), or a diaryl group whose respective aryl group is an aryl group having 6 to 20 carbon atoms which may be substituted by Z ²⁰² Amine group (i.e., Y ²⁰⁴ and Y ²⁰⁵ are -NY ²⁰⁴ Y ²⁰⁵ groups having 6 to 20 aryl groups which can be substituted by Z ²⁰¹ ), more preferably a hydrogen atom, a fluorine atom, and their respective alkyl groups may be The dialkylamino group of the alkyl group having 1 to 20 carbon atoms substituted by Z ²⁰¹ , or the respective aryl group is a diarylamino group of the aryl group having 6 to 20 carbon atoms that can be substituted by Z ²⁰² , and More preferably, it is a hydrogen atom, and each aryl group is a diarylamino group having 6 to 20 carbon aryl groups which can be substituted by Z ²⁰² , and more preferably, a simultaneous hydrogen atom or each aryl group is Z ²⁰² Diarylamino group with 6 to 20 carbon atoms.

In formula (7), p and q each independently represent an integer of 0 or more, and satisfy 2 ≦ p + q ≦ 20, preferably 2 ≦ p + q ≦ 8, more preferably 2 ≦ p + q ≦ 6, and More preferably, it is 2 ≦ p + q ≦ 4.

In particular R ²⁰¹ ~ R ²⁰⁶ and Y ²⁰¹ ~ Y ²⁰⁶ In, Z ²⁰¹ is a substituted preferably Z ²⁰² may be the carbon atoms of the aryl group having 6 to 20, more preferably the substituted phenyl group may be Z ^202, most preferably Does not exist (ie, non-substituted).

And, Z is preferably ²⁰² may be substituted by an alkyl group having a carbon number of 1 to ²⁰¹ Z of 20, more preferably a carbon number of Z may be substituted alkyl group having 1 to ²⁰¹ of the 10, and more preferably ²⁰¹ Z may be substituted by the The alkyl group having 1 to 8 carbons, and more preferably the alkyl group having 1 to 6 carbons which can be substituted by Z ²⁰¹ , is most preferably absent (ie, non-substituted).

Z ^{203 is} preferably a halogen atom, more preferably fluorine, and most preferably non-existent (ie, non-substituted).

Hereinafter, in the present invention, specific examples of aniline derivatives suitable as other charge-transporting substances are listed, but the invention is not limited thereto.

In addition, other substances that become a dopant include benzenesulfonic acid, tosic acid, p-styrenesulfonic acid, 2-naphthalenesulfonic acid, 4-hydroxybenzenesulfonic acid, 5- Sulfosalicylic Acid, p-dodecylbenzenesulfonic acid, dihexylbenzenesulfonic acid, 2,5-dihexylbenzenesulfonic acid, dibutylnaphthalenesulfonic acid, 6,7-dibutyl- 2-naphthalenesulfonic acid, dodecylnaphthalenesulfonic acid, 3-dodecyl-2-naphthalenesulfonic acid, hexylnaphthalenesulfonic acid, 4-hexyl-1-naphthalenesulfonic acid, octylnaphthalenesulfonic acid, 2-octyl 1-naphthalenesulfonic acid, hexylnaphthalenesulfonic acid, 7-hexyl-1-naphthalenesulfonic acid, 6-hexyl-2-naphthalenesulfonic acid, dinonylnaphthalenesulfonic acid, 2,7-dinonyl-4-naphthalenesulfonic acid Sulfonic acid, dinonylnaphthalenedisulfonic acid, 2,7-dinonyl-4,5-naphthalenedisulfonic acid, 1,4-benzodioxane disulfonic acid described in International Publication No. 2005/000832 Compounds, arylsulfonic acid compounds described in International Publication No. 2006/025342, arylsulfonic acid compounds described in International Publication No. 2009/096352, arylfluorene compounds such as polystyrenesulfonic acid; 10-camphorsulfonic acid Acid Non-arylfluorene compounds; 7,7,8,8-tetracyanoquinone dimethane (TCNQ), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), etc. Of organic oxidants.

Among these, other substances that become dopants are preferably arylsulfonic acid compounds. When considering the solubility in organic solvents, the molecular weight is preferably 3,000 or less, more preferably 2,000 or less, and even more preferably 1,000. the following.

In the present invention, examples of the arylsulfonic acid compound suitable as a dopant include those represented by formula (8) or (9).

In formula (8), A ¹ represents -O- or -S-, preferably -O-. A ² represents a naphthalene ring or an anthracene ring, and is preferably a naphthalene ring. A ³ represents a di- to tetravalent perfluorobiphenyl, j represents the number of bonds between A ¹ and A ³ , and satisfies the integer of 2 ≦ j ≦ 4, and A ³ is a divalent perfluorobiphenyl, preferably Is perfluorobiphenyl-4,4-diyl, and j is preferably 2. m represents the number of sulfonic acid groups bonded to A ² and is an integer satisfying 1 ≦ m ≦ 4, but is preferably 2.

In formula (9), A ⁴ to A ⁸ each independently represent a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group having 1 to 20 carbon atoms, or a halogen group having 2 to 20 carbon atoms. Alkenyl, at least three of A ⁴ to A ⁸ are halogen atoms. k represents the number of sulfonic acid groups bonded to the naphthalene ring, and is an integer satisfying 1 ≦ k ≦ 4, but is preferably 2 to 4, and more preferably 2.

Examples of the halogenated alkyl group having 1 to 20 carbon atoms include trifluoromethyl, 2,2,2-trifluoroethyl, 1,1,2,2,2-pentafluoroethyl, 3,3,3 -Trifluoroprop Base, 2,2,3,3,3-pentafluoropropyl, 1,1,2,2,3,3,3-heptafluoropropyl, 4,4,4-trifluorobutyl, 3,3 , 4,4,4-pentafluorobutyl, 2,2,3,3,4,4,4-heptafluorobutyl, 1,1,2,2,3,3,4,4,4-nine Fluorobutyl etc. Examples of the halogenated alkenyl group having 2 to 20 carbon atoms include perfluorovinyl group, 1-perfluoropropenyl group, perfluoroallyl group, and perfluorobutenyl group.

Examples of the halogen atom and the alkyl group having 1 to 20 carbon atoms are the same as those described above. The halogen atom is preferably a fluorine atom.

Among these, A ⁴ to A ^{8 are} preferably a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, or a halogenation group having 2 to 10 carbon atoms. Alkenyl, and at least 3 of A ⁴ to A ⁸ are fluorine atoms, more preferably hydrogen atom, fluorine atom, cyano group, alkyl group having 1 to 5 carbon atoms, fluorinated alkyl group having 1 to 5 carbon atoms or carbon Fluorinated alkenyl groups of 2 to 5, and at least 3 of A ⁴ to A ⁸ are fluorine atoms, and more preferably hydrogen atoms, fluorine atoms, cyano groups, perfluoroalkyl groups or carbon numbers of 1 to 5 Perfluoroalkenyl of 1 to 5, and A ⁴ , A ⁵ and A ⁸ are fluorine atoms.

In addition, a perfluoroalkyl group means a group in which all hydrogen atoms of an alkyl group are replaced by fluorine atoms, and a perfluoroalkenyl group means a group in which all hydrogen atoms of an alkenyl group are replaced by fluorine atoms.

Specific examples of the arylsulfonic acid compound suitable as the dopant of the present invention are exemplified, but are not limited thereto.

[Charge-transporting material]

The charge-transporting material of the present invention contains a charge-transporting substance and a dopant composed of a thiophene derivative represented by formula (1). Such a charge-transporting material exhibits good solubility in an organic solvent. As described above, by dissolving the charge-transporting material in an organic solvent, a charge-transporting varnish can be easily produced.

[Charge Transporting Film]

The charge-transporting varnish of the present invention is coated on a substrate, and a charge-transporting film can be formed on the substrate by firing.

The coating method of the varnish is not particularly limited. For example, there are a dipping method, a spin coating method, a transfer printing method, a roll coating method, a bristle coating method, an inkjet method, and a spray method. Better.

In addition, when the varnish of the present invention is used, the firing environment is not particularly limited, not only in the atmospheric environment, but also in an inert gas such as nitrogen or a vacuum. In addition, a thin film having a uniform film-forming surface and high charge-transporting properties can also be obtained.

The use of the obtained thin film in consideration of the firing temperature and the degree of charge transport properties imparted to the obtained thin film can be appropriately set within a range of about 100 to 260 ° C. However, the obtained thin film is used as a hole injection layer of an organic EL device. It is preferably about 140 to 250 ° C, and more preferably about 145 to 240 ° C.

One of the characteristics of the varnish of the present invention is that it can be fired at a low temperature of less than 200 ° C. Even under such firing conditions, the film produced has high flatness and high charge transportability.

In addition, during firing, a temperature change of two or more stages may be applied for the purpose of exhibiting a higher uniform film-forming property or allowing a reaction to proceed on the substrate. Heating may be performed using a suitable device such as a hot plate or an oven.

The thickness of the charge-transporting thin film is not particularly limited. When used as a hole injection layer of an organic EL device, it is preferably 5 to 200 nm. The method of changing the film thickness includes, for example, a method of changing the solid content concentration in the varnish, or changing the amount of the solution on the substrate during coating.

[Organic EL element]

Examples of the materials or manufacturing methods used in the production of OLED elements using the charge-transporting varnish of the present invention include the following, but are not limited thereto.

The electrode substrate used is preferably cleaned by washing with liquid such as lotion, alcohol, pure water in advance. For example, the anode substrate is preferably surface treated with UV ozone treatment, oxygen-plasma treatment, etc. before use. . However, when the anode material is mainly composed of organic matter, the surface treatment may not be performed.

An example of a method for manufacturing an OLED device having a hole injection layer composed of a thin film obtained from the charge-transporting varnish of the present invention is shown below.

According to the method described above, the charge-transporting varnish of the present invention is coated on the anode substrate, and a hole injection layer is formed on the electrode after firing. This was introduced into a vacuum evaporation device, and a hole transporting layer, a light emitting layer, an electron transporting layer, an electron transporting layer / hole blocking layer, an electron injection layer, and a cathode metal were sequentially vapor-deposited to form an OLED element. In addition, if necessary, an electron blocking layer may be provided between the light emitting layer and the hole transporting layer.

Examples of the anode material include metal anodes such as transparent electrodes represented by indium tin oxide (ITO), indium zinc oxide (IZO), metals represented by aluminum, or alloys thereof, and the like is preferred.化 Processor. It is also possible to use a polythiophene derivative or a polyaniline derivative having a high charge-transporting property.

In addition, other metals constituting the metal anode include rhenium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, yttrium, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, cadmium, Indium, thallium, lanthanum, cerium, praseodymium, neodymium, giant, thorium, thorium, thorium, thorium, thorium, ', thorium, thorium, thorium, thorium, thorium, tungsten, thallium, thallium, thallium, iridium, platinum, gold, titanium, Lead, bismuth, or the like, but not limited thereto.

Examples of the material forming the hole transport layer include (triphenylamine) dimer derivatives, [(triphenylamine) dimer] spiro dimers, and N, N'-bis (naphthalene-1- Group) -N, N'-bis (phenyl) -benzidine (α-NPD), N, N'-bis (naphthalene-2-yl) -N, N'-bis (phenyl) -benzidine, N, N'-bis (3-methylphenyl) -N, N'-bis (phenyl) -benzidine, N, N'-bis (3-methylphenyl) -N, N'-bis (Phenyl) -9,9-spirobifluorene, N, N'-bis (naphthalene-1-yl) -N, N'-bis (phenyl) -9,9-spirobifluorene, N, N ' -Bis (3-methylphenyl) -N, N'-bis (phenyl) -9,9-dimethyl-fluorene, N, N'-bis (naphthalene-1-yl) -N, N ' -Bis (phenyl) -9,9-dimethyl-fluorene, N, N'-bis (3-methylphenyl) -N, N'-bis (phenyl) -9,9-diphenyl -Fluorene, N, N'-bis (naphthalene-1-yl) -N, N'-bis (phenyl) -9,9-diphenyl-fluorene, N, N'-bis (naphthalene-1-yl) ) -N, N'-bis (phenyl) -2,2'-dimethylbenzidine, 2,2 ', 7,7'-tetra (N, N-diphenylamino) -9,9 -Spirobifluorene, 9,9-bis [4- (N, N-bis-biphenyl-4-yl-amino) phenyl] -9H-fluorene, 9,9-bis [4- (N, N-bis-naphthalene-2-yl-amino) phenyl] -9H-fluorene, 9,9-bis [4- (N-naphthalene-1-yl-N-phenylamino) -phenyl]- 9H-fluorene, 2,2 ', 7,7'-tetrakis [N-naphthyl (phenyl) -amino] -9,9-spirobifluorene, N, N'-bis (phenanthrene-9-yl) -N, N'-double ( ) -Benzidine, 2,2'-bis [N, N-bis (biphenyl-4-yl) amino] -9,9-spirobifluorene, 2,2'-bis (N, N- Diphenylamino) -9,9-spirobifluorene, di- [4- (N, N-bis (p-tolyl) amino) -phenyl] cyclohexane, 2,2 ', 7, 7'-tetrakis (N, N-bis (p-tolyl) amino) -9,9-spirobifluorene, N, N, N ', N'-tetra-naphthalen-2-yl-benzidine, N , N, N ', N'-tetra- (3-methylphenyl) -3,3'-dimethylbenzidine, N, N'-bis (naphthyl) -N, N'-bis (naphthalene -2-yl) -benzidine, N, N, N ', N'-tetrakis (naphthyl) -benzidine, N, N'-bis (naphthalene-2-yl) -N, N'-diphenyl Benzidine-1,4-diamine, N ¹ , N ⁴ -diphenyl-N ¹ , N ⁴ -bis (m-tolyl) benzene-1,4-diamine, N ² , N ² , N ⁶ , N ⁶ -tetraphenylnaphthalene-2,6-diamine, tris (4- (quinolin-8-yl) phenyl) amine, 2,2'-bis (3- (N, N-bis (p -Tolyl) amino) phenyl) biphenyl, 4,4 ', 4 "-tri [3-methylphenyl (phenyl) amino] triphenylamine (m-MTDATA), 4,4' Triarylamines such as 4,4 "-tri [1-naphthyl (phenyl) amino] triphenylamine (1-TNATA), 5,5" -bis- {4- [bis (4-methyl Phenyl) amino] phenyl} -2,2 ': 5', 2 "-triptythiophene (BMA-3T) and the like.

Materials for forming the light-emitting layer include, for example, ginseng (8-hydroxyquinoline) aluminum (III) (Alq ₃ ), bis (8-hydroxyquinoline) zinc (II) (Znq ₂ ), and bis (2-methyl- 8-hydroxyquinoline) -4- (p-phenylphenol) aluminum (III) (BAlq), 4,4'-bis (2,2-diphenylvinyl) biphenyl, 9,10-bis ( Naphthalene-2-yl) anthracene, 2-t-butyl-9,10-bis (naphthalene-2-yl) anthracene, 2,7-bis [9,9-bis (4-methylphenyl) -fluorene -2-yl] -9,9-bis (4-methylphenyl) fluorene, 2-methyl-9,10-bis (naphthalene-2-yl) anthracene, 2- (9,9-cyclocyclobis (Fluoren-2-yl) -9,9-cyclocyclobifluorene, 2,7-bis (9,9-cyclocyclobifluoren-2-yl) -9,9-cyclocyclobifluorene, 2- [9, 9-bis (4-methylphenyl) -fluoren-2-yl] -9,9-bis (4-methylphenyl) fluorene, 2,2'-difluorenyl-9,9-cyclocyclobis Samarium, 1,3,5-ginsyl (fluoren-1-yl) benzene, 9,9-bis [4- (fluorenyl) phenyl] -9H-fluorene, 2,2'-bi (9,10-di Phenylanthracene), 2,7-difluorenyl-9,9-cyclocyclobifluorene, 1,4-bis (fluoren-1-yl) benzene, 1,3-bis (fluoren-1-yl) benzene, 6,13-bis (biphenyl-4-yl) fused pentabenzene, 3,9-bis (naphthalene-2-yl) fluorene, 3,10-bis (naphthalene-2-yl) fluorene, reference [4- ( Fluorenyl) -phenyl] amine, 10,10'-bis (biphenyl-4-yl) -9,9'-bisanthracene, N, N'-bis (naphthalene-1-yl) -N, N ' -Diphenyl- [1,1 ': 4', 1 ": 4", 1 "'-tetraphenyl] -4,4"'-diamine 4,4'-bis [10- (naphthalene-1-yl) anthracene-9-yl] biphenyl, dibenzo {[f, f ']-4,4', 7,7'-tetraphenyl} Diindenyl [1,2,3-cd: 1 ', 2', 3'-lm] fluorene, 1- (7- (9,9'-bisanthracene-10-yl)-9,9-dimethyl -9H-fluoren-2-yl) fluorene, 1- (7- (9,9'-bisanthracene-10-yl) -9,9-dihexyl-9H-fluoren-2-yl) fluorene, 1, 3-bis (carbazole-9-yl) benzene, 1,3,5-ginsyl (carbazole-9-yl) benzene, 4,4 ', 4 "-ginsyl (carbazole-9-yl) triphenyl Amine, 4,4'-bis (carbazole-9-yl) biphenyl (CBP), 4,4'-bis (carbazole-9-yl) -2,2'-dimethylbiphenyl, 2, 7-bis (carbazol-9-yl) -9,9-dimethylfluorene, 2,2 ', 7,7'-(carbazol-9-yl) -9,9-cyclobicyclofluorene, 2,7-bis (carbazole-9-yl) -9,9-bis (p-tolyl) fluorene, 9,9-bis [4- (carbazole-9-yl) -phenyl] fluorene, 2 , 7-bis (carbazol-9-yl) -9,9-cyclocyclobifluorene, 1,4-bis (triphenylsilyl) benzene, 1,3-bis (triphenylsilyl) benzene, Bis (4-N, N-diethylamino-2-methylphenyl) -4-methylphenylmethane, 2,7-bis (carbazole-9-yl) -9,9-dioctyl Hydrazone, 4,4 "-bis (triphenylsilyl) -p-terphenyl, 4,4'-bis (triphenylsilyl) biphenyl, 9- (4-t-butylphenyl) -3,6-bis (triphenylsilyl) -9H-carbazole, 9- (4-t-butylphenyl) -3,6-bis (trityl) -9H-carbazole 9- (4-t-butylphenyl) -3,6-bis (9- (4-methoxyphenyl) -9H-fluoren-9-yl) -9H-carbazole, 2,6- Bis (3- (9H-carbazol-9-yl) phenyl) pyridine, triphenyl (4- (9-phenyl-9H-fluoren-9-yl) phenyl) silane, 9,9-dimethyl -N, N-diphenyl-7- (4- (1-phenyl-1H-benzo [d] imidazol-2-yl) phenyl) -9H-fluoren-2-amine, 3,5- Bis (3- (9H-carbazole-9-yl) phenyl) pyridine, 9,9-cyclocyclobisfluoren-2-yl-diphenyl-phosphine oxide, 9,9 '-(5- (tri Phenylsilyl) -1,3-phenylene) bis (9H-carbazole), 3- (2,7-bis (diphenylphosphonium) -9-phenyl-9H-fluorene-9- ) -9-phenyl-9H-carbazole, 4,4,8,8,12,12-hexa (p-tolyl) -4H-8H-12H-12C-azadibenzo [cd, mn ] Fluorene, 4,7-bis (9H-carbazole-9-yl) -1,10-morpholine, 2,2'-bis (4- (carbazole-9-yl) phenyl) biphenyl, 2 , 8-bis (diphenylphosphonium) dibenzo [b, d] thiophene, bis (2-methylphenyl) diphenylsilane, bis [3,5-bis (9H-carbazole-9) -Yl) phenyl] diphenylsilane, 3,6-bis (carbazole-9-yl) -9- (2-ethyl-hexyl) -9H-carbazole, 3- (diphenylphosphonium) ) -9- (4- (diphenylphosphonium) phenyl) -9H-carbazole, 3,6-bis [(3,5-diphenyl) phenyl] -9-phenylcarbazole, etc. , And can also be co-evaporated with luminescent dopants A light emitting layer is formed by plating.

Examples of the light-emitting dopant include 3- (2-benzothiazolyl) -7- (diethylamino) coumarin, 2,3,6,7-tetrahydro-1,1,7,7 -Tetramethyl-1H, 5H, 11H-10- (2-benzothiazolyl) quinazino (9,9a, 1gh) coumarin, quinacridone, N, N'-dimethyl -Quinacridone, tris (2-phenylpyridine) iridium (III) (Ir (ppy) ₃ ), bis (2-phenylpyridine) (acetylacetonate) iridium (III) (Ir ( ppy) ₂ (acac)), tris [2- (p-tolyl) pyridine] iridium (III) (Ir (mppy) ₃ ), 9,10-bis [N, N-bis (p-tolyl) amine Yl] anthracene, 9,10-bis [phenyl (m-tolyl) amino] anthracene, bis [2- (2-hydroxyphenyl) thiazolato] zinc (II), N ¹⁰ , N ¹⁰ , N ¹⁰ , N ¹⁰ -tetra (p-tolyl) -9,9'-bianthracene-10,10'-diamine, N ¹⁰ , N ¹⁰ , N ¹⁰ , N ¹⁰ -tetraphenyl -9,9, -Bienthracene-10,10'-diamine, N ¹⁰ , N ¹⁰ -Diphenyl-N ¹⁰ , N ¹⁰ -Dinaphthyl-9,9'-Bianthran-10,10'- Diamine, 4,4'-bis (9-ethyl-3-carbazole vinylidene) -1,1'-biphenyl, fluorene, 2,5,8,11-tetra-t-butylfluorene, 1,4-bis [2- (3-N-ethylcarbazolyl) vinyl] benzene, 4,4'-bis [4- (di-p-tolylamino) styryl] biphenyl, 4- (di-p-tolylamino) -4 '-[(di-p-toluene Aminoamino) styryl] fluorene, bis [3,5-difluoro-2- (2-pyridyl) phenyl- (2-carboxypyridyl)] iridium (III), 4,4'-bis [ 4- (diphenylamino) styryl] biphenyl, bis (2,4-difluorophenylpyridine) tetra (1-pyrazolyl) borate iridium (III), N, N'-bis (Naphthalene-2-yl) -N, N'-bis (phenyl) -tris (9,9-dimethylarylene), 2,7-bis {2- [phenyl (m-tolyl) Amine] -9,9-dimethyl-fluoren-7-yl} -9,9-dimethyl-fluorene, N- (4-((E) -2- (6 ((E) -4- (Diphenylamino) styryl) naphthalene-2-yl) vinyl) phenyl) -N-phenylaniline, fac-iridium (III), (1-phenyl-3-methylbenzimidazole) Chloro-2-ylidene-C, C ² ), mer-iridium (III) ginseng (1-phenyl-3-methylbenzimidazoline-2-ylidene-C, C ² ), 2,7- Bis [4- (diphenylamino) styryl] -9,9-cyclocyclodifluorene, 6-methyl-2- (4- (9- (4- (6-methylbenzo [d ] Thiazol-2-yl) phenyl) anthracene-10-yl) phenyl) benzo [d] thiazole, 1,4-bis [4- (N, N-diphenyl) amino] styrylbenzene , 1,4-bis (4- (9H-carbazole-9-yl) styryl) benzene, (E) -6- (4- (diphenylamino) styryl) -N, N- Diphenylnaphthalene-2-amine, bis (2,4-difluorophenylpyridine) (5- (pyridin-2-yl) -1H-tetrazole) iridium (III), bis (3-trifluoromethyl -5- (2-pyridine (Pyridyl) pyrazole) ((2,4-difluorobenzyl) diphenylphosphinate) iridium (III), bis (3-trifluoromethyl-5- (2-pyridyl) pyrazole) (Benzyl diphenyl phosphinate) iridium (III), bis (1- (2,4-difluorobenzyl) -3-methylbenzimidazolium) (3- (trifluoromethyl)- 5- (2-pyridyl) -1,2,4-triazole) iridium (III), bis (3-trifluoromethyl-5- (2-pyridyl) pyrazole) (4 ', 6'- Difluorophenylpyridine ester) iridium (III), bis (4 ', 6'-difluorophenylpyridine) (3,5-bis (trifluoromethyl) -2- (2'-pyridyl) pyrrole) Iridium (III), bis (4 ', 6'-difluorophenylpyridine) (3- (trifluoromethyl) -5- (2-pyridyl) -1,2,4-triazole) iridium (III ), (Z) -6-Trisyl-N- (6-trisyl (Mesityl) quinoline-2 (1H) -subunit) quinoline-2-amine-BF ₂ , (E) -2- (2- (4- (dimethylamino) styryl) -6-methyl-4H-pyran-4-ylidene) malononitrile, 4- (dicyanomethylene) -2- Methyl-6-julonidyl-9-alkenyl-4H-pyran, 4- (dicyanomethylene) -2-methyl-6- (1,1,7,7-tetramethyl Julonidyl-9-alkenyl) -4H-pyran, 4- (dicyanomethylene) -2-t-butyl-6- (1,1,7,7-tetramethyljulo Niddin-4-yl-vinyl) -4H-pyran, tris (dibenzylidenemethane) phenanthroline hydrazone (III), 5,6,11,12-tetraphenyl Tetrabenzo, bis (2-benzo [b] thiophen-2-yl-pyridine) (acetamidineacetone) iridium (III), tris (1-phenylisoquinoline) iridium (III), bis (1- Phenylisoquinoline) (Ethylacetone) iridium (III), bis [1- (9,9-dimethyl-9H-fluoren-2-yl) -isoquinoline] (Ethylacetone) iridium (III ), Bis [2- (9,9-dimethyl-9H-fluoren-2-yl) quinoline] (acetamidineacetone) iridium (III), tris [4,4'-di-t-butyl- (2,2 ')-dipyridine] ruthenium (III) ‧bis (hexafluorophosphate), tris (2-phenylquinoline) iridium (III), bis (2-phenylquinoline) (acetamidineacetone) ) Iridium (III), 2,8-di-t-butyl-5,11-bis (4-t-butylphenyl) -6,12-diphenyltetrane, bis (2 -Phenylbenzothiazole) (acetamidineacetone) iridium (III), 5,10,15,20-tetraphenyltetrabenzoporphyrin platinum, fluorene (II) bis (3-trifluoromethyl-5- (2-pyridine) -pyrazole) dimethylphenylphosphine, fluorene (II) bis (3- (trifluoromethyl) -5- (4-t-butylpyridyl) -1,2,4- Triazole) diphenylmethylphosphine, fluorene (II) bis (3- (trifluoromethyl) -5- (2-pyridyl) -1,2,4-triazole) dimethylphenylphosphine,锇 (II) bis (3- (trifluoromethyl) -5- (4-t-butylpyridyl) -1,2,4-triazole) dimethylphenylphosphine, bis [2- (4 -n-hexylphenyl) quinoline] (acetamidineacetone) iridium (III), tris [2- (4-n-hexane Phenyl) quinoline] iridium (III), tris [2-phenyl-4-methylquinoline] iridium (III), bis (2-phenylquinoline) (2- (3-methylphenyl) Pyridyl ester) iridium (III), bis (2- (9,9-diethyl-fluoren-2-yl) -1-phenyl-1H-benzo [d] imidazolato (acetamidineacetone) iridium (III), bis (2-phenylpyridine) (3- (pyridin-2-yl) -2H-chromene-2-onate) iridium (III), bis (2-phenylquinoline) (2,2,6,6-tetramethylheptane-3,5-dione) iridium (III), bis (phenylisoquinoline) (2,2,6,6-tetramethylheptane -3,5-dionic acid) iridium (III), iridium (III) bis (4-phenylthieno [3,2-c] pyridine-N, C ² ) acetamidine, (E) -2- (2-t-butyl-6- (2- (2,6,6-trimethyl-2,4,5,6-tetrahydro-1H-pyrrolo [3,2,1-ij] quinoline -8-yl) vinyl) -4H-pyran-4-ylidene) malononitrile, bis (3-trifluoromethyl-5- (1-isoquinolinyl) pyrazole) (methyldiphenyl Phosphine) ruthenium, bis [(4-n-hexylphenyl) isoquinoline] (acetamidineacetone) iridium (III), platinum (II) octaethylporphine, bis (2-methyldibenzo [ f, h] quinoxaline) (acetamidineacetone) iridium (III), tris [(4-n-hexylphenyl) hydroxyquinoline] iridium (III), and the like.

Examples of the material forming the electron transporting layer / hole blocking layer include 8-hydroxyquinoline-lithium, 2,2 ', 2 "-(1,3,5-benzyltolyl) -tris (1-phenyl) -1-H-benzimidazole), 2- (4-biphenyl) 5- (4-t-butylphenyl) -1,3,4-oxadiazole, 2,9-dimethyl- 4,7-diphenyl-1,10-phenanthroline, 4,7-diphenyl-1,10-phenanthroline, bis (2-methyl-8-quinoline) -4- (phenyl Phenolato) aluminum, 1,3-bis [2- (2,2'-dipyridine- 6-yl) -1,3,4-oxadiazol-5-yl] benzene, 6,6'-bis [5- (biphenyl-4-yl) -1,3,4-oxadiazole-2 -Yl] -2,2'-dipyridine, 3- (4-biphenyl) -4-phenyl-5-t-butylphenyl-1,2,4-triazole, 4- (naphthalene- 1-yl) -3,5-diphenyl-4H-1,2,4-triazole, 2,9-bis (naphthalene-2-yl) -4,7-diphenyl-1,10-phenanthrene Ringoline, 2,7-bis [2- (2,2'-dipyridin-6-yl) -1,3,4-oxadiazol-5-yl] -9,9-dimethylfluorene, 1 , 3-bis [2- (4-t-butylphenyl) -1,3,4-oxadiazol-5-yl] benzene, tris (2,4,6-trimethyl-3- (pyridine -3-yl) phenyl) borane, 1-methyl-2- (4- (naphthalene-2-yl) phenyl) -1H-imidazole [4,5f] [1,10] phenanthroline, 2 -(Naphthalene-2-yl) -4,7-diphenyl-1,10-phenanthroline, phenyl-diamidinophosphine oxide, 3,3 ', 5,5'-tetra [(m- Pyridyl) -phenyl-3-yl] biphenyl, 1,3,5-tri [(3-pyridyl) -phenyl-3-yl] benzene, 4,4'-bis (4,6-diphenyl -1,3,5-triazin-2-yl) biphenyl, 1,3-bis [3,5-bis (pyridin-3-yl) phenyl] benzene, bis (10-hydroxybenzo [h] Quinoline) beryllium, diphenylbis (4- (pyridin-3-yl) phenyl) silane, 3,5-bis (fluoren-1-yl) pyridine, and the like.

Examples of the material for forming the electron injection layer include lithium oxide (Li ₂ O), magnesium oxide (MgO), aluminum oxide (Al ₂ O ₃ ), lithium fluoride (LiF), sodium fluoride (NaF), and fluoride Magnesium (MgF ₂ ), cesium fluoride (CsF), strontium fluoride (SrF ₂ ), molybdenum trioxide (MoO ₃ ), aluminum, Li (acac), lithium acetate, lithium benzoate, and the like.

Examples of the cathode material include aluminum, magnesium-silver alloy, aluminum-lithium alloy, lithium, sodium, potassium, and cesium.

Examples of the material forming the electron blocking layer include tris (phenylpyrazole) iridium.

PLED element using the charge-transporting varnish of the present invention The production method is not particularly limited, and examples thereof include the following methods.

In the above-mentioned OLED device manufacturing, instead of performing a vacuum evaporation operation of a hole transporting layer, a light emitting layer, an electron transporting layer, and an electron injection layer, by sequentially forming a hole transporting polymer layer and a light emitting polymer layer, A PLED element having a charge-transporting film formed of the charge-transporting varnish of the present invention is produced.

Specifically, an anode substrate is coated with the charge-transporting varnish of the present invention, a hole injection layer is prepared by the above method, and a hole-transporting polymer layer and a light-emitting polymer layer are sequentially formed thereon, and then A cathode electrode was evaporated to form a PLED element.

The cathode and anode materials used can be the same as those used in the production of the above OLED elements, and can perform the same cleaning treatment and surface treatment.

Methods for forming the hole-transporting polymer layer and the light-emitting polymer layer include, for example, adding a solvent to the hole-transporting polymer material or the light-emitting polymer material, or adding a dopant to the solvent to dissolve the material. Or a method of uniformly dispersing and coating on a hole injection layer or a hole-transporting polymer layer, and then firing to form a film.

Examples of hole-transporting polymer materials include poly [(9,9-dihexylfluorene-2,7-diyl) -co- (N, N'-bis {p-butylphenyl} -1 , 4-diaminophenylene)], poly [(9,9-dioctylfluorene-2,7-diyl) -co- (N, N'-bis {p-butylphenyl} -1 , 1'-biphenylene-4,4-diamine)], poly [(9,9-bis {1'-pentene-5'-yl} fluorene-2,7-diyl) -co- ( N, N'-bis {p-butylphenyl} -1,4-diaminophenylene)], poly [N, N'-bis (4-but Phenyl) -N, N'-bis (phenyl) -benzidine], poly [(9,9-bis (dioctyl) fluorene-2,7-diyl) -co- (4,4 ' -(N- (p-butylphenyl)) diphenylamine)] and the like.

Light-emitting polymer materials include, for example, polyfluorene derivatives such as poly (9,9-dialkylfluorene) (PDAF), and poly (2-methoxy-5- (2'-ethylhexyloxy)- Polyphenylene vinylene derivatives such as 1,4-phenylene vinylene (MEH-PPV), polythiophene derivatives such as poly (3-alkylthiophene) (PAT), polyvinylcarbazole ( PVCz) and so on.

Examples of the solvent include toluene, xylene, and chloroform. Examples of the dissolution or uniform dispersion method include methods such as stirring, heating and stirring, and ultrasonic dispersion.

The coating method is not particularly limited, and examples thereof include an inkjet method, a spray method, a dipping method, a spin coating method, a transfer printing method, a roll coating method, and a bristle coating method. The coating is preferably performed under an inert gas such as nitrogen or argon.

Examples of the firing method include a method of heating in an oven or a hot plate under an inert gas or in a vacuum.

[Example]

Hereinafter, the present invention will be described more specifically with reference to synthesis examples and examples, but the present invention is not limited to the following examples. The equipment used is as follows.

(1) Substrate cleaning: Substrate cleaning device made by Changzhou Industry Co., Ltd. (decompression plasma system)

(2) Coating of varnish: Mikasa (strand), spin coater MS-A100

(3) Film thickness measurement: Surfcorder ET-4000, a micro-shape measuring machine manufactured by Kosaka Laboratory

(4) Production of EL elements: Multi-function vapor deposition system C-E2L1G1-N made by Changzhou Industry Co., Ltd.

(5) Measurement of EL element brightness, etc .: (with) Tech world, I-V-L measurement system

(6) EL element life measurement (durability evaluation): (stock) organic EL brightness life evaluation system PEL-105S manufactured by Eetch Sea

(7) NMR measurement: JNM-ECX300 FT NMR SYSTEM manufactured by Japan Electronics Co., Ltd.

(8) MS measurement: Bruker (stock) autoflex III smartbem

[Synthesis Example 1] Synthesis of thiophene derivative 1 (formula (1-1)) [1] Synthesis of 5-tributylstannyl-2,2'-bisthiophene

4.0 g of 2,2'-bisthiophene (manufactured by Tokyo Chemical Industry Co., Ltd.) was placed in a reaction vessel, and after nitrogen substitution, 120 mL of tetrahydrofuran was added and cooled to -78 ° C. While maintaining -78 ° C, 14.7 mL (concentration: 1.64 mol / L) of n-hexane solution of n-butyllithium was dropped, and then stirred for 30 minutes. After dripping 7.8 mL (d1.20) of tri-n-butylchlorostannane into it, After stirring for 10 minutes, the temperature was raised to room temperature and stirred. After 6 hours, the reaction solution was concentrated, and 50 mL of n-hexane was added to the obtained residue, and insoluble matter was removed by filtration (cake washing: 30 mL of n-hexane). The obtained filtrate was concentrated and dried to obtain 12.64 g of a dark red oil containing 5-tributylstannyl-2,2'-bisthiophene. Without further purification, the yield in this step was 100% (theoretical yield 10.96 g), and the purity (10.96 / 12.64 × 100 = 86.7%) was calculated and used as the raw material in the next step.

[2] Synthesis of thiophene derivative 1

2.0 g of tributylphenylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) and 0.24 g of Pd (PPh ₃ ) _{4 were} placed in a reaction vessel, and after nitrogen substitution, 5 prepared by [1] prepared in advance was added. -100 mL of a dimethylformamide (DMF) solution of 7.8 g (purity 86.7%) of tributylstannyl-2,2'-bisthiophene. After stirring at 110 ° C for 2.5 hours, the reaction solution was reprecipitated with 1.5 L of methanol. The slurry was stirred at room temperature for 15 hours, and then filtered. 90 mL of toluene, 10 mL of ethanol, and 0.75 g of activated carbon were added to the obtained filtrate, and the mixture was stirred under reflux for 1 hour. Filtration was performed while hot, and the obtained filtrate was cooled to 0 ° C with stirring, and stirring was continued at 0 ° C for 2 hours. The slurry was filtered, and the filtrate was dried (80 ° C, 2 hours) to obtain the intended thiophene derivative 1 (1.4 g) (yield: 47%). The measurement results of ¹ H-NMR and TOF-MS are shown below.

¹ H-NMR (300 MHz, CDCl ₃ ) δ [ppm]: 7.51 (d, J = 8.4 Hz, 6H), 7.13-7.22 (m, 18H), 7.01-7.04 (m, 3H).

MALDI-TOF-MS m / Z found: 737.29 ([M] ⁺ calcd: 737.05).

[Example 1-1]

0.387 g of thiophene derivative 1 (0.077 g) and phosphotungstic acid (PTA, manufactured by Kanto Chemical Co., Ltd.) were dissolved in 7.5 g of N, N-dimethylacetamide. To the obtained solution, 7.5 g of diethylene glycol dimethyl ether was added, and after stirring, 0.014 g of pentafluorophenyltriethoxysilane was added thereto, and the charge-transporting varnish was prepared by stirring.

[Examples 1-2 and 1-3]

The method was the same as that of Example 1-1, except that the amounts of thiophene derivative 1 and PTA were set to 0.042 g and 0.422 g (Example 1-2), 0.022 g, and 0.353 g (Example 1-3). Modulates charge-transporting varnish.

[Example 1-4]

0.062 g of thiophene derivative and 0.309 g of PTA were dissolved in 1,3-dimethylformaldehyde In 3.6 g of 2-imidazolinone. To the obtained solution were added 2.4 g of 1,3-butanediol and 6.0 g of diethylene glycol dimethyl ether, and after stirring, 0.026 g of F4TCNQ (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the solution, and the charge was transferred by stirring. Sexual varnish.

[Example 1-5]

A charge-transporting varnish was prepared in the same manner as in Examples 1-4 except that the amounts of thiophene derivative 1 and PTA were set to 0.034 g and 0.337 g.

[Example 1-6]

Thiophene derivative 1 (0.052 g) and PTA (0.258 g) were dissolved in 3 g of 1,3-dimethyl-2-imidazolinone. To the obtained solution, 3 g of 1,3-butanediol and 4 g of diethylene glycol dimethyl ether were added, and after stirring, F4TCNQ (0.031 g) was added thereto to prepare a charge-transporting varnish.

[Example 2-1]

After applying the varnish obtained in Example 1-1 on an ITO substrate using a spin coater, it was dried at 50 ° C for 5 minutes, and then fired at 150 ° C for 10 minutes in an atmospheric environment to form 30 nm on the ITO substrate. A uniform film. The ITO substrate is a 25mm × 25mm × 0.7t glass substrate formed by patterning indium tin oxide (ITO) with a film thickness of 150nm on the surface. Before use, it is cleaned by an O ₂ plasma cleaning device (150W, 30 seconds) to remove impurities from the surface.

Next, N, N'-bis (1-naphthyl) -N, N'-bisphenyl was sequentially laminated on the ITO substrate on which the thin film was formed using a vapor deposition apparatus (vacuum degree: 1.0 × 10 ^-5 Pa). -Thin films of benzidine (α-NPD), ginseng (8-hydroxyquinoline) aluminum (III) (Alq ₃ ), lithium fluoride, and aluminum to obtain an organic EL device. At this time, regarding the evaporation rate, α-NPD, Alq _3, and aluminum were performed at 0.2 nm / sec, and lithium fluoride was performed at 0.02 nm / sec. The film thicknesses were 30 nm, 40 nm, 0.5 nm, and 120 nm, respectively.

In addition, in order to prevent deterioration of characteristics due to the influence of oxygen, water, and the like in the air, the organic EL element is sealed with a sealing substrate, and its characteristics are evaluated. Sealing is performed in the following order.

In a nitrogen environment with an oxygen concentration of 2 ppm or less and a dew point of -85 ° C or less, an organic EL element is housed between the sealing substrates, and the sealing substrate is bonded with an adhesive material (XNR5516Z-B1 made by Nagase Chemtex). At this time, a water-capturing agent (HD-071010W-40, manufactured by Dynic Co., Ltd.) was housed in the sealed substrate together with the organic EL element.

The bonded sealing substrate was irradiated with UV light (wavelength: 365 nm, irradiation amount: 6000 mJ / cm ² ), and then annealed at 80 ° C. for 1 hour to harden the adhesive material.

[Examples 2-2 to 2-6]

An organic EL device was produced in the same manner as in Example 2-1, except that the varnish obtained in Examples 1-2 to 1-6 was used instead of the varnish obtained in Example 1-1.

Measure the current density and brightness when the driving voltage of each component is 5V degree. The results are shown in Table 1.

As shown in Table 1, the varnish of the present invention can realize an organic EL element having excellent brightness characteristics.

The elements manufactured in Examples 2-1 to 2-6 were subjected to a durability test. The half-life of luminance (initial luminance 5,000 cd / m ² ) is shown in Table 2.

As shown in Table 2, an organic EL device having excellent durability can be realized by the varnish of the present invention.

Claims (10)

A charge-transporting varnish comprising a charge-transporting substance, a dopant, and an organic solvent composed of a thiophene derivative represented by formula (1),

(Wherein R ¹ to R ²¹ each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, an aldehyde group, a hydroxyl group, a thiol group, a carboxylic acid group, and an alkane having 1 to 20 carbon atoms which may be substituted by Z ¹ group, may be substituted with Z ¹ of the carbon atoms of the alkenyl group having 2 to 20, Z ¹ may be substituted with an alkynyl group of a carbon number of 2 to 20, Z ² may be substituted having 6 to 20 carbon atoms of the aryl group, -C ( O) Y ¹ group, -OY ² group, -SY ³ group, -C (O) OY ⁴ group, -OC (O) Y ⁵ group, -C (O) NHY ⁶ group, or -C (O) NY ⁷ group Y ^8, Y ¹ ~ Y ⁸ each independently represent Z ¹ may be substituted having 1 to 20 carbon atoms of the alkyl group, may be substituted with Z ¹ of the carbon atoms of the alkenyl group having 2 to 20, Z ¹ may be substituted with a carbon number of An alkynyl group of 2 to 20 or an aryl group of 6 to 20 carbon atoms that can be substituted by Z ² ; Z ¹ represents a halogen atom, a nitro group, a cyano group, an aldehyde group, a hydroxyl group, a thiol group, a sulfonic acid group, and a carboxylic acid group Or an aryl group having 6 to 20 carbon atoms which may be substituted by Z ³ , Z ² represents a halogen atom, a nitro group, a cyano group, an aldehyde group, a hydroxyl group, a thiol group, a sulfonic acid group, a carboxylic acid group, and may be substituted by Z ³ Alkyl group having 1 to 20 carbon atoms, alkenyl group having 2 to 20 carbon atoms which can be substituted with Z ³ or alkynyl group having 2 to 20 carbon atoms which can be substituted with Z ³ , Z ³ represents a halogen atom, a nitro group, a cyanide Group, aldehyde group, hydroxyl group, thiol group, sulfone Group or a carboxylic acid group, n ¹ ~ n ³ each independently represents an integer of from 2 to 10). For example, the charge-transporting varnish according to item 1 of the application, wherein the dopant includes a heteropoly acid. For example, the charge-transporting varnish according to item 1 or 2 of the patent application scope further comprises an organic silane compound. For example, the charge-transporting varnish according to any one of claims 1 to 3 in the patent application scope further comprises a tetracyanobenzoquinone dimethane compound represented by the following formula (6),

(In the formula, R ¹⁰¹ to R ¹⁰⁴ each independently represent a hydrogen atom or a halogen atom, but at least one is a halogen atom.) A charge-transporting film characterized by using a charge-transporting varnish according to any one of claims 1 to 4 of the scope of patent application. An organic electroluminescence device is characterized by having a charge-transporting film as described in item 5 of the patent application scope. For example, the organic electroluminescence device according to item 6 of the patent application, wherein the charge transporting film is a hole injection layer or a hole transport layer. A method for manufacturing a charge-transporting film, which is characterized in that a charge-transporting varnish according to any one of claims 1 to 4 is applied to a substrate Fired on wood. A method for manufacturing an organic electroluminescence element, which uses a charge-transporting film such as the item 4 in the scope of patent application. A charge transporting material characterized by containing a charge transporting substance and a dopant composed of a thiophene derivative represented by formula (1),

(Wherein R ¹ to R ²¹ each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, an aldehyde group, a hydroxyl group, a thiol group, a carboxylic acid group, and an alkane having 1 to 20 carbon atoms which may be substituted by Z ¹ group, may be substituted with Z ¹ of the carbon atoms of the alkenyl group having 2 to 20, Z ¹ may be substituted with an alkynyl group of a carbon number of 2 to 20, Z ² may be substituted having 6 to 20 carbon atoms of the aryl group, -C ( O) Y ¹ group, -OY ² group, -SY ³ group, -C (O) OY ⁴ group, -OC (O) Y ⁵ group, -C (O) NHY ⁶ group, or -C (O) NY ⁷ group Y ^8, Y ¹ ~ Y ⁸ each independently represent Z ¹ may be substituted having 1 to 20 carbon atoms of the alkyl group, may be substituted with Z ¹ of the carbon atoms of the alkenyl group having 2 to 20, Z ¹ may be substituted with a carbon number of An alkynyl group of 2 to 20 or an aryl group of 6 to 20 carbon atoms that can be substituted by Z ² ; Z ¹ represents a halogen atom, a nitro group, a cyano group, an aldehyde group, a hydroxyl group, a thiol group, a sulfonic acid group, and a carboxylic acid group Or an aryl group having 6 to 20 carbon atoms which may be substituted by Z ³ , Z ² represents a halogen atom, a nitro group, a cyano group, an aldehyde group, a hydroxyl group, a thiol group, a sulfonic acid group, a carboxylic acid group, and may be substituted by Z ³ Alkyl group having 1 to 20 carbon atoms, alkenyl group having 2 to 20 carbon atoms which can be substituted with Z ³ or alkynyl group having 2 to 20 carbon atoms which can be substituted with Z ³ , Z ³ represents a halogen atom, a nitro group, a cyanide Group, aldehyde group, hydroxyl group, thiol group, sulfone Group or a carboxylic acid group, n ¹ ~ n ³ each independently represents an integer of from 2 to 10).