TWI856118B - Charge transport coatings - Google Patents

Abstract

The present invention provides a charge transport coating comprising (A) a monodisperse charge transport organic compound, (B) a blend and (C) an organic solvent, wherein the (B) blend comprises (B1) an aryl sulfonate compound, (B2) a halogenated tetracyanoquinodimethane, or (B3) a halogenated or cyanated benzoquinone.

Description

Charge transport coatings

The present invention relates to charge transport coatings.

The formation methods of organic functional layers such as hole injection layers used in organic electroluminescent (EL) elements can be roughly divided into dry processes represented by evaporation and wet processes represented by spin coating. When comparing these processes, wet processes can more efficiently produce large-area and highly flat thin films. Therefore, with the current promotion of large-area organic EL displays, a method that can form a hole injection layer in a wet process is desired. In view of such circumstances, the applicant of this case has developed a charge transporting material that can be applied to various wet processes and, when applied to the hole injection layer of an organic EL element, can provide a thin film with excellent EL element characteristics, or a compound that has good solubility in an organic solvent used therefor (for example, refer to patent documents 1 to 3).

In the manufacture of organic EL displays, when forming a hole injection layer or other organic functional layers in a wet process, generally, a partition wall (bank) is set to enclose the layer formation area, and an organic functional ink is applied to the opening of the partition wall. At this time, the ink applied in the opening climbs to the side of the partition wall, and the thickness of the peripheral portion of the coating in contact with the side of the partition wall is thicker than the central portion of the coating, resulting in the so-called crawling phenomenon. When such a crawling phenomenon occurs, the multiple organic functional layers formed between the electrodes cannot function in the layering sequence, and a leakage current path is formed. As a result, the desired device characteristics cannot be achieved. In addition, the climbing of organic functional layers such as the hole injection layer sometimes causes uneven light emission of the resulting organic EL element. Although patent documents 4 and 5 propose to suppress the climbing phenomenon, the development of organic EL displays using wet processes has been further accelerated, and expectations for the technology to suppress such climbing phenomenon are even higher. [Prior technical documents] [Patent document]

[Patent Document 1] International Publication No. 2008/129947 [Patent Document 2] International Publication No. 2015/050253 [Patent Document 3] International Publication No. 2017/217457 [Patent Document 4] Japanese Patent Publication No. 2009-104859 [Patent Document 5] Japanese Patent Publication No. 2011-103222

[Problem solved by the invention]

The present invention was made in view of the above-mentioned matters, and is intended to provide a charge transport coating that does not produce a creeping phenomenon, and when a thin film obtained from the coating is applied to a hole injection layer, etc., the charge transport coating can realize an organic EL element with excellent characteristics. [Means for Solving the Problem]

The inventors of the present invention have repeatedly conducted detailed studies to achieve the above-mentioned purpose and have found that when a charge transport coating containing (A) a monodisperse charge transporting organic compound, (B) a blend containing two predetermined types of compounds, and (C) an organic solvent is applied to the interior of a partition wall by a wet process, the coating can be extremely inhibited from climbing up, thereby completing the present invention.

That is, the present invention provides the following charge transporting coatings. 1. A charge transporting coating comprising (A) a monodisperse charge transporting organic compound, (B) a blend and (C) an organic solvent, wherein (B) the blend contains (B1) an aromatic sulfonate compound and (B2) a halogenated tetracyanoquinodimethane, or (B3) a halogenated or cyanated benzoquinone. 2. The charge transporting coating according to 1. above, wherein the monodisperse charge transporting organic compound is an aromatic amine derivative. 3. The charge transporting coating according to 2. above, wherein the aromatic amine derivative is a tertiary aromatic amine compound. 4. The charge transporting coating according to 3. above, wherein the tertiary aromatic amine compound has at least one nitrogen atom, and all nitrogen atoms have a tertiary aromatic amine structure. 5. The charge transport coating according to 4. above, wherein the tertiary arylamine compound has at least two nitrogen atoms, and all the nitrogen atoms have a tertiary arylamine structure. 6. The charge transport coating according to any one of 1. to 5. above, wherein the aryl sulfonate compound is represented by the following formula (B1) or (B1'). [In the formula, ^A1 is an m-valent alkyl group having 6 to 20 carbon atoms and containing one or more aromatic rings which may have a substituent, or an m-valent group derived from a compound represented by the following formula (B1a) or (B1b); (wherein, ^W1 and ^W2 are independently -O-, -S-, -S(O)- or -S(O2)-, or -N-, -Si-, -P- or -P(O)- which may have a substituent) ^A2 is -O-, -S- or -NH-; ^A3 is or is an (n+ ₁ )-valent aromatic group having 6 to 20 carbon atoms; ^X1 is an alkylene group having 2 to 5 carbon atoms, wherein -O-, -S- or a carbonyl group may be present between the carbon atoms of the alkylene group, and a part or all of the hydrogen atoms of the alkylene group may be further substituted by an alkyl group having 1 to 20 carbon atoms; ^X2 is a single bond, -O-, -S- or -NR-, and R is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms; ^X3 is a monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent; m is an integer satisfying 1≦m≦4; n is an integer satisfying 1≦n≦4]. 7. The charge transport coating according to 6. above, wherein the aryl sulfonate compound is a compound represented by any one of the following formulae (B1-1) to (B1-3). (wherein, ^Rs1 to ^Rs4 are each independently a hydrogen atom, or a linear or branched alkyl group having 1 to 6 carbon atoms, ^Rs5 is a monovalent alkyl group having 2 to 20 carbon atoms which may have a substituent; ^A11 is an m-valent group derived from perfluorobiphenyl, ^A12 is -O- or -S-, and ^A13 is an (n+1)-valent group derived from naphthalene or anthracene; m and n are the same as above) (wherein, R ^s6 and R ^s7 are each independently a hydrogen atom, or a linear or branched monovalent aliphatic alkyl group, R ^s8 is a linear or branched monovalent aliphatic alkyl group, but the total number of carbon atoms of R ^s6 , R ^s7 and R ^s8 is 6 or more; A ¹⁴ may have a substituent and is an m-valent alkyl group containing one or more aromatic rings; A ¹⁵ is -O- or -S-; A ¹⁶ is an (n+1)-valent aromatic group; m and n are the same as above) (wherein, R ^s9 to R ^s13 are each independently a hydrogen atom, a nitro group, a cyano group, a halogen atom, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, or a halogenated alkenyl group having 2 to 10 carbon atoms; R ^s14 to R ^s17 are each independently a hydrogen atom, or a linear or branched monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms; R ^s18 is a linear or branched monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, or -OR ^s19 , R ^s19 is a monovalent hydrocarbon group having 2 to 20 carbon atoms which may have a substituent; A ¹⁷ is -O-, -S- or -NH-; A ¹⁸ is an (n+1)-valent aromatic group; n is the same as described above). 8. (B2) The charge transport coating according to any one of 1. to 7. above, wherein the halogenated tetracyanoquinodimethane is represented by the following formula (B2). (In the formula, R ^q1 to R ^q4 are each independently a hydrogen atom or a halogen atom, but at least one of them is a halogen atom.) 9. (B3) The charge transporting coating according to any one of 1. to 8. above, wherein the halogenated or cyanated benzoquinone is represented by the following formula (B3). (wherein, ^Rq5 to ^Rq8 are each independently a hydrogen atom, a halogen atom or a cyano group, but at least one is a halogen atom or a cyano group.) 10. A charge transport coating according to any one of 1. to 9. above, wherein the molar ratio of the (B1) aryl sulfonate compound to the (B2) halogenated tetracyanoquinodimethane or the (B3) halogenated or cyanated benzoquinone is 0.01 to 50. 11. A charge transport coating according to any one of 1. to 10. above, wherein the molecular weight of the monodisperse charge transport organic compound is 200 to 9,000. 12. A charge transport coating according to any one of 1. to 11. above, wherein the organic solvent is a low-polarity organic solvent. 13. A charge transporting film obtained from any of the charge transporting coating materials described in 1. to 12. 14. An organic EL device having the charge transporting film described in 13. 15. An organic EL device described in 14. wherein the charge transporting film is a hole injection layer or a hole transport layer. [Effects of the Invention]

By using the charge transport coating of the present invention, even when the coating is applied inside the partition in a wet process, a charge transport thin film can be manufactured in which the climbing of the coating (so-called spreading) can be extremely suppressed. In addition, the charge transport thin film obtained by the charge transport coating of the present invention has excellent flatness and charge transport properties. Therefore, the charge transport coating of the present invention can be applied to thin films for electronic components represented by organic EL components, and is particularly suitable for the manufacture of thin films for organic EL displays.

[Type of implementation of the invention] [Charge transport coating]

The charge transport coating of the present invention is a charge transport coating comprising (A) a monodispersed charge transport organic compound, (B) a blend and (C) an organic solvent, wherein the (B) blend comprises (B1) an aryl sulfonate compound, (B2) a halogenated tetracyanoquinodimethane or (B3) a halogenated or cyanated benzoquinone.

[(A) Charge transporting organic compound] For the present invention, as the charge transporting organic compound, for example, those used in the field of organic EL in the past can be used. As specific examples, various charge transporting organic compounds can be cited, such as oligoaniline derivatives, N,N'-diarylbenzidine derivatives, N,N,N',N'-tetraarylbenzidine derivatives and other arylamine derivatives (aniline derivatives), oligothiophene derivatives, thienothiophene derivatives, thienothiophene derivatives and other thienothiophene derivatives, oligopyrrole and other pyrrole derivatives. Among them, arylamine derivatives and thiophene derivatives are preferred.

For the present invention, the aforementioned charge transporting organic compound must be monodisperse (i.e., the molecular weight distribution is 1). If an oligomer or polymer having a molecular weight distribution is used, the effect of suppressing the creeping phenomenon will become insufficient. The molecular weight of the aforementioned charge transporting organic compound is generally about 200 to 9,000 from the perspective of preparing a uniform coating that imparts a thin film with high flatness, but from the perspective of obtaining a thin film with excellent charge transport properties, it is preferably 300 or more, and more preferably 400 or more. From the perspective of being able to prepare a uniform coating that imparts high flatness and better reproducibility to a thin film, it is preferably 8,000 or less, more preferably 7,000 or less, more preferably 6,000 or less, and even more preferably 5,000 or less.

Examples of the charge transporting organic compound include Japanese Patent Application Publication No. 2002-151272, International Publication No. 2004/105446, International Publication No. 2005/043962, International Publication No. 2008/032617, International Publication No. 2008/032616, International Publication No. 2013/042623, International Publication No. 2014/141998, International Publication No. 2014/185208, International Publication No. 2015/050253, International Publication No. 2015/ International Publication No. 2015/137395, International Publication No. 2015/146912, International Publication No. 2015/146965, International Publication No. 2016/190326, International Publication No. 2016/136544, International Publication No. 2016/204079, etc.

Furthermore, the charge transporting organic compound is preferably a tertiary arylamine compound having at least one nitrogen atom, and all nitrogen atoms have a tertiary arylamine structure. That is, the tertiary arylamine compound has at least one nitrogen atom, and all nitrogen atoms have a structure in which three aromatic groups are bonded. Among the tertiary arylamine compounds, those having two or more nitrogen atoms are preferred.

Preferred examples of the tertiary arylamine compound include compounds represented by the following formula (A1) or (A2).

In formula (A2), ^R1 and ^R2 are each independently a hydrogen atom, a halogen atom, a nitro group, or an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a heteroaryl group having 2 to 20 carbon atoms which may be substituted by a cyano group or a halogen atom.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like.

The aforementioned alkyl group having 1 to 20 carbon atoms may be any of linear, branched, or cyclic. Specific examples thereof include linear or branched alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl; and cyclic alkyl groups having 3 to 20 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, bicyclobutyl, bicyclopentyl, bicyclohexyl, bicycloheptyl, bicyclooctyl, bicyclononyl, and bicyclodecyl.

The alkenyl group having 2 to 20 carbon atoms may be in any of a linear, branched or cyclic form, and specific examples thereof include vinyl, 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-pentenyl, n-1-decenyl, and n-1-eicosenyl.

The alkynyl group having 2 to 20 carbon atoms may be linear, branched or cyclic. Specific examples thereof 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-pentadecinyl, and n-1-eicosynyl.

Examples of the aryl group having 6 to 20 carbon atoms include phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthrenyl, 2-phenanthrenyl, 3-phenanthrenyl, 4-phenanthrenyl, and 9-phenanthrenyl.

Examples of the heteroaryl group having 2 to 20 carbon atoms include 2-thienyl, 3-thienyl, 2-furyl, 3-furyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 3-isoxazolyl, 4-isoxazolyl, 5-isoxazolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 3-isothiazolyl, 4-isothiazolyl, 5-isothiazolyl, 2-imidazolyl, 4-imidazolyl, 2-pyridyl, 3-pyridyl, and 4-pyridyl.

Among them, ^R1 and ^R2 are preferably a hydrogen atom, a fluorine atom, a cyano group, an alkyl group having 1 to 20 carbon atoms which may be substituted by a halogen atom, an aryl group having 6 to 20 carbon atoms which may be substituted by a halogen atom, or a heteroaryl group having 2 to 20 carbon atoms which may be substituted by a halogen atom. A hydrogen atom, a fluorine atom, a cyano group, an alkyl group having 1 to 10 carbon atoms which may be substituted by a halogen atom, or a phenyl group which may be substituted by a halogen atom is more preferred. A hydrogen atom or a fluorine atom is more preferred, and a hydrogen atom is most preferred.

In formulae (A1) and (A2), ^Ph1 is a group represented by formula (P1).

In formula (P1), the dashed line represents a bond. ^{R 3} to R ⁶ are each independently a hydrogen atom, a halogen atom, a nitro group or a cyano group, or an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a heteroaryl group having 2 to 20 carbon atoms which may be substituted by a halogen atom. As specific examples of these, the same ones as those described in the description of R ¹ and R ² can be cited.

Particularly, R ³ to R ⁶ are preferably a hydrogen atom, a fluorine atom, a cyano group, an alkyl group having 1 to 20 carbon atoms which may be substituted by a halogen atom, an aryl group having 6 to 20 carbon atoms which may be substituted by a halogen atom, or a heteroaryl group having 2 to 20 carbon atoms which may be substituted by a halogen atom. More preferably, they are a hydrogen atom, a fluorine atom, a cyano group, an alkyl group having 1 to 10 carbon atoms which may be substituted by a halogen atom, or a phenyl group which may be substituted by a halogen atom. More preferably, they are a hydrogen atom or a fluorine atom. Most preferably, a hydrogen atom is.

As a preferred group of Ph ¹ , 1,4-phenylene group can be mentioned, but the present invention is not limited to this.

In formula (A1), Ar ¹ is independently any one of the following formulae (Ar1-1) to (Ar1-11), and is particularly preferably any one of the following formulae (Ar1-1') to (Ar1-11').

In formula (Ar1-1) to (Ar1-11) and formula (Ar1-1') to (Ar1-11'), the dashed line is a bond. ^R7 to ^R27 , ^R30 to ^R51 and ^R53 to ^R154 are each independently a hydrogen atom, a halogen atom, a nitro group or a cyano group, or a diphenylamino group which may be substituted by a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a heteroaryl group having 2 to 20 carbon atoms. ^R28 and ^R29 are each independently an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms which may be substituted by ^Z1 . R ⁵² is an aryl group having 6 to 20 carbon atoms which may be substituted by Z ¹ or a heteroaryl group having 2 to 20 carbon atoms.

^Z1 is a halogen atom, a nitro group or a cyano group, or an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an alkynyl group having 2 to 20 carbon atoms ^which may be substituted by Z2. ^Z2 is a halogen atom, a nitro group or a cyano group, or an aryl group having 6 to 20 carbon atoms, or a heteroaryl group having 2 to 20 carbon atoms which may be substituted by ^Z3 . ^Z3 is a halogen atom, a nitro group or a cyano group.

Particularly, as ^R7 to ^R27 , ^R30 to ^R51 and ^R53 to ^R154 , a hydrogen atom, a fluorine atom, a cyano group, a diphenylamino group which may be substituted by a halogen atom, an alkyl group having 1 to 20 carbon atoms which may be substituted by a halogen atom, an aryl group having 6 to 20 carbon atoms which may be substituted by a halogen atom, or a heteroaryl group having 2 to 20 carbon atoms which may be substituted by a halogen atom is preferred; a hydrogen atom, a fluorine atom, a cyano group, an alkyl group having 1 to 10 carbon atoms which may be substituted by a halogen atom, or a phenyl group which may be substituted by a halogen atom is more preferred; a hydrogen atom or a fluorine atom is more preferred, and a hydrogen atom is most preferred.

R ²⁸ and R ²⁹ are preferably an aryl group having 6 to 14 carbon atoms which may be substituted by a halogen atom, or a heteroaryl group having 2 to 14 carbon atoms which may be substituted by a halogen atom, more preferably a phenyl group which may be substituted by a halogen atom, or a naphthyl group which may be substituted by a halogen atom, more preferably a phenyl group which may be substituted by a halogen atom, and even more preferably a phenyl group.

R ⁵² is preferably a hydrogen atom or an aryl group having 6 to 20 carbon atoms which may be substituted by Z ¹ , more preferably a hydrogen atom, a phenyl group which may be substituted by Z ¹ , or a naphthyl group which may be substituted by Z ¹ , more preferably a phenyl group which may be substituted by Z ¹ , and even more preferably a phenyl group.

In the formula (Ar1-10), (Ar1-11), (Ar1-10') and (Ar1-11'), ^Ar4 is independently an aryl group having 6 to 20 carbon atoms, wherein each aryl group may be substituted by a diarylamino group of an aryl group having 6 to 20 carbon atoms. Specific examples of the aryl group having 6 to 20 carbon atoms include the same ones as described above for ^R1 and ^R2 . Specific examples of the diarylamino group include diphenylamino, 1-naphthylphenylamino, di(1-naphthyl)amino, 1-naphthyl-2-naphthylamino, di(2-naphthyl)amino and the like.

Ar ⁴ is preferably phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl, 9-phenanthryl, p-(diphenylamino)phenyl, p-(1-naphthylphenylamino)phenyl, p-(di(1-naphthyl)amino)phenyl, p-(1-naphthyl-2-naphthylamino)phenyl, p-[di(2-naphthyl)amino]phenyl, and more preferably p-(diphenylamino)phenyl.

In formula (A1), Ar ² is independently any of the groups shown in formulas (Ar2-1) to (Ar2-18), but is particularly preferably any of the groups shown in formulas (Ar2-1'-1) to (Ar2-18'-2). In the following formula, Ar ⁴ is the same as above, DPA is a diphenylamine group, and the dotted line is a bonding bond.

In the formula (Ar2-16), (Ar2-16'-1) and (Ar2-16'-2), R ¹⁵⁵ is a hydrogen atom, an aryl group having 6 to 14 carbon atoms which may be substituted by Z ¹ , or a heteroaryl group having 2 to 14 carbon atoms which may be substituted by Z ^1. Examples of the aryl group and heteroaryl group include the same ones as those described in the description of R ¹ and R ² . Among them, R ¹⁵⁵ is preferably a hydrogen atom, a phenyl group which may be substituted by Z ¹ , a 1-naphthyl group which may be substituted by Z ¹ , a 2-naphthyl group which may be substituted by Z ¹ , a 2-pyridyl group which may be substituted by Z ¹ , a phenyl group which may be substituted by Z ¹ , a 3-pyridyl group which may be substituted by the phenyl group, or a 4-pyridyl group which may be substituted by Z ¹ , more preferably a phenyl group which may be substituted by Z ¹ , and still more preferably a phenyl group or a (2,3,5,6-tetrafluoro-4-(trifluoromethyl)phenyl) group.

In the formula (Ar2-17), (Ar2-17'-1) and (Ar2-17'-2), ^R156 and ^R157 are phenyl which may be substituted by ^Z1 , aryl having 6 to 14 carbon atoms which may be substituted by the phenyl, phenyl which may be substituted by ^Z1 , and heteroaryl having 2 to 14 carbon atoms which may be substituted by the phenyl. As the aforementioned aryl and heteroaryl, the same ones as those described in the explanation of ^R1 and ^R2 can be cited. Among them, ^R156 and ^R157 are preferably phenyl which may be substituted by ^Z1 , and aryl having 6 to 14 carbon atoms which may be substituted by the phenyl, and more preferably phenyl which may be substituted by ^Z1 , phenyl which may be substituted by the phenyl, phenyl which may be substituted by ^Z1 , 1-naphthyl which may be substituted by the phenyl, or 2-naphthyl which may be substituted by ^Z1 .

In formula (A2), Ar ³ is a group represented by any one of formulas (Ar3-1) to (Ar3-8), and is particularly preferably a group represented by any one of formulas (Ar3-1') to (Ar3-8'). In the following formula, DPA is the same as above, and the dotted line is a bonding bond.

In formula (A1), p is an integer of 1 to 10, but from the viewpoint of improving the solubility of the compound in organic solvents, 1 to 5 is preferred, 1 to 3 is more preferred, 1 or 2 is more preferred, and 1 is most preferred. In formula (A2), q is 1 or 2.

The aniline derivative represented by formula (A1) and the aniline derivative represented by formula (A2) can be produced, for example, according to the method described in International Publication No. 2015/050253.

Other preferred examples of the tertiary arylamine compound include compounds represented by the following formula (A3).

In formula (A3), r is an integer of 2 to 4. Ar ¹¹ is an r-valent aromatic group having 6 to 20 carbon atoms which may be substituted. The aromatic group is a group obtained by removing r hydrogen atoms from an aromatic ring of an aromatic compound having 6 to 20 carbon atoms. As the aromatic group, a group derived from a compound represented by any one of the following formulas (A3-1) to (A3-8) is particularly preferred.

In formulas (A3-3) and (A3-4), L ¹ to L ³ are each independently a single bond, -(CR ²⁰¹ R ²⁰² ) _s -, -C(O)-, -O-, -S-, -S(O)-, -S(O ₂ )-, or -NR ²⁰³ -. s is an integer from 1 to 6. In formulas (A3-5) to (A3-8), L ⁴ to L ¹³ are each independently a single bond, -CR ²⁰¹ R ²⁰² -, -C(O)-, -O-, -S-, -S(O)-, -S(O ₂ )-, or -NR ²⁰³ -. R ²⁰¹ and R ²⁰² are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, and R ²⁰¹ and R ²⁰² are bonded to each other and can form a ring together with the carbon atoms to which they are bonded. In addition, in -(CR ²⁰¹ R ²⁰² ) _s -, when s is 2 or more, each R ²⁰¹ and R ²⁰² may be the same or different. R ²⁰³ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms.

In addition, in the aforementioned aromatic group, part or all of the hydrogen atoms may be further substituted by a substituent. Examples of the aforementioned substituent include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitro group, a cyano group, a hydroxyl group, an amine group, a silanol group, a thiol group, a carboxyl group, a sulfonate group, a phosphoric acid group, a phosphoric acid ester group, an ester group, a thioester group, an amide group, a monovalent alkyl group, an organic oxygen group, an organic amine group, an organic silicon group, an organic thio group, an acyl group, a sulfonic acid group, etc., preferably a halogen atom, a nitro group, a cyano group, or a monovalent alkyl group having 1 to 20 carbon atoms.

Ar ¹¹ is preferably an optionally substituted 1,4-phenylene group, fluorene-2,7-diyl group, 9,9-dimethylfluorene-2,7-diyl group or the like, and more preferably an optionally substituted 1,4-phenylene group or biphenyl-4,4'-diyl group.

In formula (A3), Ar ¹² and Ar ¹³ are each independently a monovalent aromatic group having 6 to 20 carbon atoms substituted by Z ¹¹ , and Ar ¹² and Ar ¹³ are bonded to each other and can form a ring together with the nitrogen atom to which they are bonded. Ar ¹² and Ar ¹³ can be the same or different from each other. Z ¹¹ is a halogen atom, a nitro group or a cyano group, or a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic group which may be substituted by a halogen atom, or a polymerizable group.

Examples of the monovalent aromatic group include phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthrenyl, 2-phenanthrenyl, 3-phenanthrenyl, 4-phenanthrenyl, 9-phenanthrenyl, 2-biphenylyl, 3-biphenylyl, 4-biphenylyl and the like.

The monovalent aliphatic hydrocarbon may be in the form of a straight chain, a branched chain or a ring. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl and n-dodecyl; and alkenyl groups having 2 to 20 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, isopropenyl, 1-methyl-2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl and hexenyl.

Examples of the polymerizable group include those represented by the following formulae, but the group is not limited thereto.

In the formula, the dotted line is a bond. ^Ra is a hydrogen atom or a methyl group. ^Rb and ^Rd are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, preferably a methyl group or an ethyl group. ^Rc , ^Re and ^Rf are each independently a single bond or an alkylene group having 1 to 8 carbon atoms which may contain an oxygen atom, a sulfur atom or a nitrogen atom. ^Rg , ^Rh and ^Ri are each independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms such as a methyl group, an ethyl group or an n-propyl group.

Y ^a and Y ^b are each independently a single bond or a divalent aromatic group having 6 to 20 carbon atoms. Examples of the divalent aromatic group include 1,3-phenylene, 1,4-phenylene, 1,5-naphthylene, 1,6-naphthylene, 1,7-naphthylene, 2,6-naphthylene, and 4,4'-biphenylene. Among these, 1,3-phenylene or 1,4-phenylene is preferred.

Ar ^a is a monovalent aromatic group having 6 to 20 carbon atoms which may have a substituent. Examples of the monovalent aromatic group include the same as those mentioned above.

Z ¹¹ is preferably a methyl group, an ethyl group, a polymerizable group represented by the following formula, or the like. (In the formula, the dashed line is the bond.)

Preferred examples of Ar ¹² and Ar ¹³ include phenyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 2-ethylphenyl, 3-ethylphenyl, 4-ethylphenyl, 2-vinylphenyl, 3-vinylphenyl, 4-vinylphenyl, 1-naphthyl and 2-naphthyl.

The compound represented by formula (A3) can be synthesized by a known method, or a commercial product can be used.

Other preferred examples of the tertiary arylamine compound include those represented by the following formula (A4).

In formula (A4), Ar ²¹ to Ar ²³ are each independently a divalent aromatic group having 6 to 20 carbon atoms. The divalent aromatic group is preferably a divalent group derived from a compound represented by formula (A3-1), (A3-3) or (A3-4).

Among them, Ar ²¹ to Ar ²³ are preferably 1,4-phenylene, biphenyl-4,4'-diyl, terphenyl-4,4"-diyl, etc., and more preferably 1,4-phenylene or biphenyl-4,4'-diyl.

In formula (A4), Ar ²⁴ to Ar ²⁹ are each independently a monovalent aromatic group having 6 to 20 carbon atoms substituted by Z ^21. Examples of the monovalent aromatic group include phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthrenyl, 2-phenanthrenyl, 3-phenanthrenyl, 4-phenanthrenyl, 9-phenanthrenyl, 2-biphenylyl, 3-biphenylyl, 4-biphenylyl and the like.

Z ²¹ is a halogen atom, a nitro group or a cyano group, a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms which may be substituted by a halogen atom, a nitro group or a cyano group, -N(Ar ³⁰ )(Ar ³¹ ), or a polymerizable group. The monovalent aliphatic alkyl group having 1 to 20 carbon atoms may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl and n-dodecyl; and alkenyl groups having 2 to 20 carbon atoms such as vinyl, 1-propenyl, 2-propenyl, isopropenyl, 1-methyl-2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl and hexenyl. As the polymerizable group, the same as those mentioned above can be mentioned.

Ar ³⁰ and Ar ³¹ are each independently an aryl group having 6 to 20 carbon atoms substituted by Z ²² , and these groups may be bonded to each other and to the nitrogen atom bonded thereto to form a ring. ^{Z 22} is a halogen atom, a nitro group or a cyano group, or a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms which may be substituted by a halogen atom, a nitro group or a cyano group.

Examples of the aryl group having 6 to 20 carbon atoms and the monovalent aliphatic alkyl group having 1 to 20 carbon atoms include the same as those mentioned above.

Ar ³⁰ and Ar ³¹ are preferably phenyl, 1-naphthyl, 2-naphthyl, or 1-biphenylyl, and more preferably phenyl or 1-biphenylyl.

Particularly preferred as -N(Ar ³⁰ )(Ar ³¹ ) are diphenylamino, phenyl(4-biphenylyl)amino, bis(4-biphenylyl)amino, N-carbazolyl and the like.

Z ²¹ is preferably an alkyl group having 1 to 10 carbon atoms, -N(Ar ³⁰ )(Ar ³¹ ) or the like.

Preferred examples of Ar ²⁴ to Ar ²⁹ include phenyl, 4-biphenylyl, 4-diphenylaminophenyl, 4-phenyl(4-biphenylyl)aminophenyl, bis(4-biphenylyl)aminophenyl, 4'-diphenylamino-4-biphenylyl, 4-phenyl(4-biphenylyl)amino-4-biphenylyl, 4'-bis(4-biphenylyl)amino-4-biphenylyl, N-carbazolylphenyl, and 4'-N-carbazolyl-4-biphenylyl.

The compound represented by formula (A4) can be synthesized by a known method, or a commercial product can be used.

Other preferred examples of the tertiary arylamine compound include those represented by the following formula (A5).

In formula (A5), Ar ⁴¹ and Ar ⁴² are each independently a phenyl group, a 1-naphthyl group or a 2-naphthyl group. R ³⁰¹ and R ³⁰² are each independently a hydrogen atom, and each aryl group is a diarylaminophenyl group of an aryl group having 6 to 20 carbon atoms, a chlorine atom, a bromine atom or an iodine atom. Examples of the aryl group include the same ones as those described in the description of R ¹ and R ² in formula (A2). ^{L 21} is a divalent linking group containing a propane-2,2-diyl group or a 1,1,1,3,3,3-hexafluoropropane-2,2-diyl group. x is an integer of 1 to 10.

The compound represented by formula (A5) can be synthesized by a known method, or a commercial product can be used.

The aforementioned tertiary arylamine compound is not limited to the aforementioned one if it has at least one nitrogen atom and all nitrogen atoms have a tertiary arylamine structure. Other tertiary arylamine compounds that can be used in the present invention include, for example, arylamine compounds described in International Publication No. 2005/094133, polymerizable compounds having a triarylamine partial structure and a polymerizable group described in Patent No. 5287455, triarylamine compounds described in Patent No. 5602191, and compounds described in paragraph [0054] of Patent No. 6177771.

As the tertiary arylamine compound, preferably, the following are mentioned, but the present invention is not limited thereto.

[(B) Admixture] The admixture as the (B) component in the charge transport coating of the present invention may contain (B1) an aryl sulfonate compound and (B2) a halogenated tetracyanoquinodimethane or (B3) a halogenated or cyanated benzoquinone.

[(B1) Aryl sulfonate compound] The aforementioned aryl sulfonate compound is not particularly limited as long as it is a compound having a sulfonate group bonded to an aromatic ring. In a preferred embodiment of the present invention, the molecular weight of the aforementioned aryl sulfonate compound is preferably 100 or more, preferably 200 or more, preferably 5,000 or less, preferably 4,000 or less, more preferably 3,000 or less, and more preferably 2,000 or less. In a preferred embodiment of the present invention, the number of sulfonate groups possessed by the aforementioned aryl sulfonate compound is preferably 2 or more, preferably 3 or more, preferably 6 or less, and more preferably 5 or less. In a preferred embodiment of the present invention, the aforementioned aryl sulfonate compound preferably contains an aromatic ring substituted with fluorine.

The arylsulfonate compound is preferably one represented by the following formula (B1) or (B1′).

In formula (B1) and (B1'), ^A1 is an m-valent alkyl group having 6 to 20 carbon atoms and containing one or more aromatic rings which may have substituents, or an m-valent group derived from a compound represented by the following formula (B1a) or (B1b) (i.e., a group obtained by removing m hydrogen atoms from the aromatic ring of the compound represented by the following formula (B1a) or (B1b)). (wherein ^W1 and ^W2 are each independently -O-, -S-, -S(O)- or -S( _O2 )-, or -N-, -Si-, -P- or -P(O)- which may have a substituent).

The m-valent hydrocarbon group having 6 to 20 carbon atoms and containing one or more aromatic rings is a group obtained by removing m hydrogen atoms from a hydrocarbon group having 6 to 20 carbon atoms and containing one or more aromatic rings. Examples of the hydrocarbon group having one or more aromatic rings include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, pyrene, and the like. Among these, the m-valent hydrocarbon group is preferably a group derived from benzene, biphenyl, and the like.

The aforementioned alkyl group is a group in which a part or all of the hydrogen atom may be further substituted by a substituent. The aforementioned substituent may be substituted by a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitro group, a cyano group, a hydroxyl group, an amine group, a silanol group, a thiol group, a carboxyl group, a sulfonate group, a phosphoric acid group, a phosphoric acid ester group, an ester group, a thioester group, an amide group, a monovalent alkyl group, an organic oxygen group, an organic amine group, an organic silicon group, an organic sulfur group, an acyl group, a sulfonic acid group, etc.

The monovalent alkyl group may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 10 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl and n-decyl; alkenyl groups having 2 to 10 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, isopropenyl, 1-methyl-2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl and hexenyl; aryl groups having 6 to 20 carbon atoms, such as phenyl, xylyl, tolyl, 1-naphthyl and 2-naphthyl; and aralkyl groups having 7 to 20 carbon atoms, such as benzyl and phenylethyl.

Examples of the organic oxy group include alkoxy, alkenyloxy, and aryloxy. Examples of the alkyl, alkenyl, and aryl groups included therein include the same as those mentioned above.

Examples of the organic amine group include alkylamine groups having 1 to 12 carbon atoms, such as methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, cyclohexylamine, heptylamine, octylamine, nonylamine, decylamine, and dodecylamine; dialkylamine groups in which each alkyl group is an alkyl group having 1 to 12 carbon atoms, such as dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, dicyclohexylamine, diheptylamine, dioctylamine, dinonylamine, and dodecylamine; and morpholino groups.

Examples of the organic silicon group include trialkylsilyl groups each of which is an alkyl group having 1 to 10 carbon atoms, such as trimethylsilyl, triethylsilyl, tripropylsilyl, tributylsilyl, tripentylsilyl, trihexylsilyl, pentyldimethylsilyl, hexyldimethylsilyl, octyldimethylsilyl, and decyldimethylsilyl.

Examples of the organic thio group include alkylthio groups having 1 to 12 carbon atoms, such as methylthio, ethylthio, propylthio, butylthio, pentylthio, hexylthio, heptylthio, octylthio, nonylthio, decylthio and dodecylthio.

Examples of the acyl group include acyl groups having 1 to 10 carbon atoms, such as methyl group, acetyl group, propionyl group, butyryl group, isobutyryl group, vanillyl group, isovinyl group and benzoyl group.

Furthermore, the carbon number of the monovalent alkyl group, organic oxygen group, organic amine group, organic silicon group, organic sulfur group and acyl group is preferably 1 to 8.

Among these substituents, a fluorine atom, a sulfonic acid group, an alkyl group, an organic oxygen group, and an organic silicon group are preferred.

In formula (B1), ^A2 is -O-, -S- or -NH-. Among them, -O- is preferred from the viewpoint of ease of synthesis.

In formula (B1), ^A3 is an (n+1)-valent aromatic group having 6 to 20 carbon atoms. The aforementioned aromatic group is a group obtained by removing (n+1) hydrogen atoms on the aromatic ring from an aromatic compound having 6 to 20 carbon atoms. In addition, the aromatic compound in the present invention represents an aromatic hydrocarbon and an aromatic heterocyclic compound. As the aforementioned aromatic compound, benzene, toluene, xylene, biphenyl, naphthalene, anthracene, pyrene, etc. can be cited, but among these, as the aromatic group represented by ^A3 , a group derived from naphthalene or anthracene is preferred.

In formula (B1) and (B1'), ^X1 is an alkylene group having 2 to 5 carbon atoms. The aforementioned alkylene group may be interposed between the carbon atoms (carbon-carbon bonds) by -O-, -S- or a carbonyl group, and part or all of the hydrogen atoms may be further replaced by an alkyl group having 1 to 20 carbon atoms. ^X1 is preferably an ethylene group, a trimethylene group, a methyleneoxymethylene group, a methylenethiomethylene group, or the like, and part or all of the hydrogen atoms of these groups may be further replaced by an alkyl group having 1 to 20 carbon atoms. Examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, bicyclohexyl and the like.

In formula (B1) and (B1'), ^X2 is a single bond, -O-, -S- or -NR-. R is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. The monovalent hydrocarbon group is preferably an alkyl group such as methyl, ethyl, or n-propyl. ^X2 is preferably a single bond, -O- or -S-, and more preferably a single bond or -O-.

In formula (B1) and (B1'), ^X3 is a monovalent alkyl group having 1 to 20 carbon atoms which may be substituted. The monovalent alkyl group may be any of a linear, branched, or cyclic group, and specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, and bicyclic hexyl; vinyl, 1-propenyl, 2-propenyl, isopropenyl, , 1-methyl-2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, hexenyl and other alkenyl groups having 2 to 20 carbon atoms; phenyl, xylyl, tolyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthrenyl, 2-phenanthrenyl, 3-phenanthrenyl, 4-phenanthrenyl, 9-phenanthrenyl, 2-biphenyl, 3-biphenyl, 4-biphenyl and other aryl groups having 6 to 20 carbon atoms; benzyl, phenylethyl, phenylcyclohexyl and other aralkyl groups having 7 to 20 carbon atoms. In addition, part or all of the hydrogen atoms of the above-mentioned monovalent alkyl groups may be further substituted with substituents. As the above-mentioned substituents, the same ones as those described in the description of A ¹ can be cited. As X ³ , an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms is preferred.

In formulas (B1) and (B1'), m is an integer satisfying 1≦m≦4, preferably 2. n is an integer satisfying 1≦n≦4, preferably 2.

The aryl sulfonate compounds represented by formula (B1) and (B1') have high solubility in a wide range of solvents including low polarity solvents, so the physical properties of the solution can be adjusted using a variety of solvents, and the coating characteristics are high. Therefore, it is preferred to coat in the sulfonate state and to generate sulfonic acid during the drying or calcining of the coating film. The temperature at which sulfonic acid is generated from the sulfonate is stable at room temperature and preferably below the calcination temperature, so 40 to 260°C is preferred. And if the high stability in the coating and the ease of release during calcination are taken into consideration, 80 to 230°C is preferred, and 120 to 180°C is more preferred.

The arylsulfonate compound represented by formula (B1) is preferably any one of the following formulas (B1-1) to (B1-3).

In formula (B1-1), A ¹¹ is an m-valent group derived from perfluorobiphenyl (i.e., a group obtained by removing m fluorine atoms from perfluorobiphenyl). A ¹² is -O- or -S-, but -O- is preferred. ^{A 13} is an (n+1)-valent group derived from naphthalene or anthracene (i.e., a group obtained by removing (n+1) hydrogen atoms from naphthalene or anthracene), but a group derived from naphthalene is preferred.

In formula (B1-1), R ^s1 to R ^s4 are each independently a hydrogen atom, or a linear or branched alkyl group having 1 to 6 carbon atoms, and R ^s5 is a monovalent hydrocarbon group having 2 to 20 carbon atoms which may be substituted.

Examples of the linear or branched alkyl group having 1 to 6 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-hexyl, etc. Among these, the alkyl group having 1 to 3 carbon atoms is preferred.

The aforementioned monovalent hydrocarbon group having 2 to 20 carbon atoms may be in any of a linear, branched, or cyclic form, and specific examples thereof include alkyl groups such as ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl; and aryl groups such as phenyl, naphthyl, and phenanthrenyl.

Among ^Rs1 to ^Rs4 , ^Rs1 or ^Rs3 is a straight chain alkyl group having 1 to 3 carbon atoms, and the others are preferably hydrogen atoms. Furthermore, ^Rs1 is a straight chain alkyl group having 1 to 3 carbon atoms, and ^Rs2 to ^Rs4 are preferably hydrogen atoms. The straight chain alkyl group having 1 to 3 carbon atoms is preferably a methyl group. Furthermore, ^Rs5 is preferably a straight chain alkyl group having 2 to 4 carbon atoms or a phenyl group.

In formula (B1-1), m is an integer satisfying 1≦m≦4, preferably 2. n is an integer satisfying 1≦n≦4, preferably 2.

In formula (B1-2), ^A14 is an m-valent alkyl group having 6 to 20 carbon atoms and containing one or more aromatic rings which may be substituted. The alkyl group is a group obtained by removing m hydrogen atoms from a alkyl group having 6 to 20 carbon atoms and containing one or more aromatic rings. Examples of the alkyl group include benzene, toluene, xylene, ethylbenzene, biphenyl, naphthalene, anthracene, phenanthrene, and the like.

In the above-mentioned alkyl group, part or all of the hydrogen atoms may be further substituted by a substituent, and examples of such a substituent include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitro group, a cyano group, a hydroxyl group, an amino group, a silanol group, a thiol group, a carboxyl group, a sulfonate group, a phosphoric acid group, a phosphoric acid ester group, an ester group, a thioester group, an amide group, a monovalent alkyl group, an organic oxygen group, an organic amino group, an organic silyl group, an organic thio group, an acyl group, a sulfonic acid group, and the like. Among these, A ¹⁴ is preferably a group derived from benzene, biphenyl, and the like.

In formula (B1-2), ^A15 is -O- or -S-, but -O- is preferred.

In formula (B1-2), ^A16 is an (n+1)-valent aromatic hydrocarbon group having 6 to 20 carbon atoms. The aromatic hydrocarbon group is a group obtained by removing (n+1) hydrogen atoms from the aromatic ring of an aromatic hydrocarbon compound having 6 to 20 carbon atoms. Examples of the aromatic hydrocarbon compound include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, pyrene, and the like. Among these, ^A16 is preferably a group derived from naphthalene or anthracene, and more preferably a group derived from naphthalene.

In formula (B1-2), R ^s6 and R ^s7 are each independently a hydrogen atom or a linear or branched monovalent aliphatic alkyl group. R ^s8 is a linear or branched monovalent aliphatic alkyl group. However, the total number of carbon atoms of R ^s6 , R ^s7 and R ^s8 is 6 or more. The upper limit of the total number of carbon atoms of R ^s6 , R ^s7 and R ^s8 is not particularly limited, but is preferably 20 or less, more preferably 10 or less.

Specific examples of the aforementioned linear or branched monovalent aliphatic hydrocarbon group include alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-hexyl, n-octyl, 2-ethylhexyl, and decyl; and alkenyl groups having 2 to 20 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, isopropenyl, 1-methyl-2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, and hexenyl.

R ^s6 is preferably a hydrogen atom, and R ^s7 and R ^s8 are preferably an alkyl group having 1 to 6 carbon atoms. In this case, R ^s7 and R ^s8 may be the same or different.

In formula (B1-2), m is an integer satisfying 1≦m≦4, preferably 2. n is an integer satisfying 1≦n≦4, preferably 2.

In formula (B1-3), R ^s9 to R ^s13 are each independently a hydrogen atom, a nitro group, a cyano group, a halogen atom, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, or a halogenated alkenyl group having 2 to 10 carbon atoms.

The aforementioned alkyl group having 1 to 10 carbon atoms may be any of linear, branched, or cyclic. Specific examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl.

The halogenated alkyl group having 1 to 10 carbon atoms is not particularly limited as long as a part or all of the hydrogen atoms of the alkyl group having 1 to 10 carbon atoms are substituted by halogen atoms. The halogenated alkyl group may be any of a linear, branched, or cyclic group, and specific examples thereof include trifluoromethyl, 2,2,2-trifluoroethyl, 1,1,2,2,2-pentafluoroethyl, 3,3,3-trifluoropropyl, 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, and 1,1,2,2,3,3,4,4,4-nonafluorobutyl.

The aforementioned halogenated alkenyl group having 2 to 10 carbon atoms is not particularly limited as long as a part or all of the hydrogen atoms of the alkenyl group having 2 to 10 carbon atoms are substituted by halogen atoms. Specific examples thereof include perfluorovinyl, perfluoro-1-propenyl, perfluoro-2-propenyl, perfluoro-1-butenyl, perfluoro-2-butenyl, and perfluoro-3-butenyl.

Among them, R ^s9 is preferably a nitro group, a cyano group, a halogenated alkyl group having 1 to 10 carbon atoms, a halogenated alkenyl group having 2 to 10 carbon atoms, etc., more preferably a nitro group, a cyano group, a halogenated alkyl group having 1 to 4 carbon atoms, a halogenated alkenyl group having 2 to 4 carbon atoms, etc., and more preferably a nitro group, a cyano group, a trifluoromethyl group, a perfluoropropenyl group, etc. Moreover, R ^s10 to R ^s13 are preferably a halogen atom, and more preferably a fluorine atom.

In formula (B1-3), ^A17 is -O-, -S- or -NH-, preferably -O-.

In formula (B1-3), A ¹⁸ is an (n+1)-valent aromatic hydrocarbon group having 6 to 20 carbon atoms. The aromatic hydrocarbon group is a group obtained by removing (n+1) hydrogen atoms from the aromatic ring of an aromatic hydrocarbon compound having 6 to 20 carbon atoms. Examples of the aromatic hydrocarbon compound include benzene, toluene, xylene, biphenyl, naphthalene, anthracene, pyrene, and the like. Among these, A ¹⁸ is preferably a group derived from naphthalene or anthracene, and more preferably a group derived from naphthalene.

In formula (B1-3), R ^s14 to R ^s17 are each independently a hydrogen atom, or a linear or branched monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms. The monovalent aliphatic alkyl group may be any of a linear, branched or cyclic group, and specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, cyclopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl and n-dodecyl; and alkenyl groups having 2 to 20 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, isopropenyl, 1-methyl-2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl and hexenyl. Among them, an alkyl group having 1 to 20 carbon atoms is preferred, an alkyl group having 1 to 10 carbon atoms is more preferred, and an alkyl group having 1 to 8 carbon atoms is even more preferred.

In formula (B1-3), R ^s18 is a linear or branched monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, or -OR ^s19 . R ^s19 is a monovalent hydrocarbon group having 2 to 20 carbon atoms which may be substituted.

As the linear or branched monovalent aliphatic alkyl group having 1 to 20 carbon atoms represented by R ^s18 , the same ones as those described in the description of R ^s14 to R ^s17 can be cited. When R ^s18 is a monovalent aliphatic alkyl group, R ^s18 is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, and even more preferably an alkyl group having 1 to 8 carbon atoms.

As the monovalent alkyl group having 2 to 20 carbon atoms represented by R ^s19 , examples of the monovalent aliphatic alkyl group include phenyl, naphthyl, phenanthryl and other aryl groups, in addition to methyl. Among them, R ^s19 is preferably a linear alkyl group having 2 to 4 carbon atoms or a phenyl group. In addition, examples of the substituent group which may have a monovalent alkyl group include a fluorine atom, an alkoxy group having 1 to 4 carbon atoms, a nitro group, a cyano group and the like.

In formula (B1-3), n is an integer satisfying 1≦n≦4, and 2 is preferred.

As the arylsulfonate compound represented by the formula (B1-3), one represented by the following formula (B1-3-1) or (B1-3-2) is particularly preferred.

In formula (B1-3-1) and (B1-3-2), ^A17 , ^A18 , ^Rs9 to ^Rs17 , ^Rs19 and n are the same as those described above. ^Rs20 is a linear or branched monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, and specific examples thereof include those described in the description of ^Rs18 .

In the arylsulfonate compound represented by formula (B1-3-1), among ^Rs14 to ^Rs17 , ^Rs14 or ^Rs16 is a straight-chain alkyl group having 1 to 3 carbon atoms, and the rest are preferably hydrogen atoms. Further, ^Rs14 is a straight-chain alkyl group having 1 to 3 carbon atoms, and ^Rs15 to ^Rs17 are preferably hydrogen atoms. The straight-chain alkyl group having 1 to 3 carbon atoms is preferably a methyl group. Moreover, ^Rs19 is preferably a straight-chain alkyl group having 2 to 4 carbon atoms or a phenyl group.

For the arylsulfonate compound represented by formula (B1-3-2), the total carbon number of ^Rs14 , ^Rs16 and ^Rs20 is preferably 6 or more. The upper limit of the total carbon number of ^Rs14 , ^Rs16 and ^Rs20 is preferably 20 or less, and more preferably 10 or less. In this case, ^Rs14 is preferably a hydrogen atom, and ^Rs16 and ^Rs20 are preferably an alkyl group having 1 to 6 carbon atoms. In addition, ^Rs16 and ^Rs20 may be the same or different from each other.

The arylsulfonate compound represented by formula (B1) may be used alone or in combination of two or more.

Specific examples of preferred arylsulfonate compounds include the following, but the compounds are not limited thereto.

The aryl sulfonate compound represented by formula (B1) can be synthesized, for example, by reacting a sulfonate compound represented by formula (B1A) with a halogenating agent as shown in the following process A to synthesize a sulfonyl halide represented by formula (B1B) (hereinafter also referred to as step 1), and reacting the sulfonyl halide with a compound represented by formula (B1C) (hereinafter also referred to as step 2). (In the formula, A ¹ to A ³ , X ¹ to X ³ , m and n are the same as those described above. ^{M +} is a monovalent cation such as a sodium ion, a potassium ion, a pyridinium ion, a quaternary ammonium ion, etc. Hal is a halogen atom such as a chlorine atom or a bromine atom).

The sulfonate compound represented by formula (B1A) can be synthesized according to a known method.

As the halogenating agent used in step 1, there can be mentioned thionyl chloride, oxalyl chloride, phosphorus oxychloride, phosphorus (V) chloride and the like, but thionyl chloride is preferred. The amount of the halogenating agent used is not particularly limited as long as it is 1 mole or more of the sulfonate compound, but it is preferred to use 2 to 10 times the mass ratio of the sulfonate compound.

As the reaction solvent used in step 1, a solvent that does not react with the halogenating agent is preferred, and examples thereof include chloroform, dichloroethane, carbon tetrachloride, hexane, heptane, and the like. In addition, the reaction can also be carried out without a solvent, and in this case, it is preferred to use a halogenating agent in an amount greater than that which can form a uniform solution at the end of the reaction. In addition, to promote the reaction, a catalyst such as N,N-dimethylformamide can be used. The reaction temperature can be about 0 to 150°C, but preferably 20 to 100°C and below the boiling point of the halogenating agent used. After the reaction is completed, the crude product obtained by decompression concentration is generally used in the next step.

Examples of the compound represented by formula (B1C) include ethylene glycol ethers such as propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol monophenyl ether, ethylene glycol monobutyl ether, and ethylene glycol monohexyl ether; and alcohols such as 2-ethyl-1-hexanol, 2-butyl-1-octanol, 1-octanol, and 3-nonanol.

For step 2, a base may also be used. Examples of the base include sodium hydride, pyridine, triethylamine, diisopropylethylamine, etc., but sodium hydride, pyridine, and triethylamine are preferred. The amount of the base used is preferably 1 times the molar amount of the solvent relative to the sulfonyl halide.

As the reaction solvent used in step 2, various organic solvents can be used, but tetrahydrofuran, dichloroethane, chloroform, and pyridine are preferred. Although the reaction temperature is not particularly limited, it is preferably 0 to 80°C. After the reaction is completed, the pure aryl sulfonate compound can be obtained by post-treatment and purification using conventional methods such as reduced pressure concentration, liquid separation extraction, water washing, reprecipitation, recrystallization, and chromatography. In addition, by subjecting the obtained pure aryl sulfonate compound to heat treatment, a high-purity sulfonic acid compound can be obtained.

In addition, the aryl sulfonate compound represented by formula (B1) can be synthesized from the sulfonic acid compound represented by formula (B1D) as shown in the following process B. In the following process B, the halogenating agent, the compound represented by formula (B1C), the reaction solvent and other components used in the reactions of the first and second steps can be the same as those used in steps 1 and 2 in process A. (wherein, A ¹ to A ³ , X ¹ to X ³ , Hal, m and n are the same as above).

The sulfonic acid compound represented by formula (B1D) can be synthesized according to a known method.

The arylsulfonate compound represented by formula (B1') can be synthesized according to conventional methods, for example, according to the method described in Patent No. 5136795.

[(B2) Tetracyanoquinodimethane halogenide] The tetracyanoquinodimethane halogenide is preferably one represented by the following formula (B2).

In formula (B2-1), ^Rq1 to ^Rq4 are each independently a hydrogen atom or a halogen atom, but at least one of them is a halogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, preferably a fluorine atom or a chlorine atom, and more preferably a fluorine atom. Furthermore, at least two of ^Rq1 to ^Rq4 are halogen atoms, more preferably at least three are halogen atoms, and most preferably all of them are halogen atoms.

Examples of the tetracyanoquinodimethane derivative include 7,7,8,8-tetracyanoquinodimethane (TCNQ), 2-fluoro-7,7,8,8-tetracyanoquinodimethane, 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane, tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), tetrachloro-7,7,8,8-tetracyanoquinodimethane, 2-fluoro-7,7,8,8-tetracyanoquinodimethane, 2-chloro-7,7,8,8-tetracyanoquinodimethane, 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane, and 2,5-dichloro-7,7,8,8-tetracyanoquinodimethane. Among these, F4TCNQ is preferred.

[(B3) Halogenated or cyanated benzoquinone] The halogenated or cyanated benzoquinone is preferably a benzoquinone represented by formula (B3).

In formula (B2-2), R ^q5 to R ^q8 are each independently a hydrogen atom, a halogen atom or a cyano group, but at least one is a halogen atom or a cyano group. As the aforementioned halogen atom, the same as those shown above can be cited, preferably a fluorine atom or a chlorine atom, and more preferably a fluorine atom. In addition, at least two of R ^q5 to R ^q8 are preferably halogen atoms or cyano groups, preferably at least three are halogen atoms or cyano groups, and even more preferably all are halogen atoms or cyano groups.

Specific examples of the halogenated or cyanated benzoquinone include 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), tetrachloro-1,4-benzoquinone (chloranil), trifluoro-1,4-benzoquinone, tetrafluoro-1,4-benzoquinone, tetrabromo-1,4-benzoquinone, tetracyano-1,4-benzoquinone, etc. Among them, 2,3-dichloro-5,6-dicyano-p-benzoquinone, trifluorobenzoquinone, tetrafluorobenzoquinone, and tetracyanobenzoquinone are preferred, DDQ, chloranil, tetrafluoro-1,4-benzoquinone, and tetracyano-1,4-benzoquinone are more preferred, and DDQ is even more preferred.

In the blend of component (B), the content of the aryl sulfonate compound (B1) is generally about 0.01 to 50, preferably about 0.1 to 20, and more preferably about 1.0 to 10, calculated as a molar ratio, to the (B2) halogenated tetracyanoquinodimethane or (B3) halogenated or cyanated benzoquinone. In addition, the content ratio (D/H) of the total content of the blend of component (B) to the content ratio of the blend of the charge transporting organic compound is generally about 0.01 to 50, preferably about 0.1 to 10, and more preferably about 1.0 to 5.0, calculated as a molar ratio.

Furthermore, (B2) halogenated tetracyanoquinodimethane may be used alone or in combination of two or more thereof, and (B3) halogenated or cyanated benzoquinone may be used alone or in combination of two or more thereof. Furthermore, (B2) halogenated tetracyanoquinodimethane and (B3) halogenated or cyanated benzoquinone may be used in combination.

[(C) Organic solvent] As (C) organic solvent, any solvent that can dissolve or disperse the aforementioned components or the optional components described below is not particularly limited, but from the perspective of excellent process suitability, it is preferred to use a low-polarity solvent. For the present invention, a so-called low-polarity solvent is defined as a solvent having a specific conductivity of less than 7 at a frequency of 100 kHz, and a so-called high-polarity solvent is defined as a solvent having a specific conductivity of 7 or more at a frequency of 100 kHz.

Examples of the low polarity solvent include chlorine-based solvents such as chloroform and chlorobenzene; aromatic hydrocarbon-based solvents such as toluene, xylene, tetrahydronaphthalene, cyclohexylbenzene, and decylbenzene; aliphatic alcohol-based solvents such as 1-octanol, 1-nonanol, and 1-decanol; tetrahydrofuran, dioxane, anisole, 4-methoxytoluene, 3-phenoxytoluene, benzhydryl ether, diethylene glycol dimethyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, and the like. Ether solvents include ether, triethylene glycol butyl methyl ether, etc.; ester solvents such as methyl benzoate, ethyl benzoate, butyl benzoate, isoamyl benzoate, bis(2-ethylhexyl) phthalate, dimethyl phthalate, diisopropyl malonate, dibutyl maleate, dibutyl oxalate, hexyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, and diethylene glycol monobutyl ether acetate.

Examples of the highly polar solvent include amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylisobutylamide, N-methylpyrrolidone, and 1,3-dimethyl-2-imidazolidinone; ketone solvents such as ethyl methyl ketone, isophorone, and cyclohexanone; cyano solvents such as acetonitrile and 3-methoxypropionitrile; ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, and the like; Polyhydric alcohol solvents such as 1,3-butanediol, 2,3-butanediol, etc.; monohydric alcohol solvents other than aliphatic alcohols such as diethylene glycol monomethyl ether, diethylene glycol monophenyl ether, triethylene glycol monomethyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, benzyl alcohol, 2-phenoxyethanol, 2-benzyloxyethanol, 3-phenoxybenzyl alcohol, tetrahydrofurfuryl alcohol, etc.; sulfoxide solvents such as dimethyl sulfoxide, etc.

(C) The amount of organic solvent used is generally 0.1 to 20% by mass, preferably 0.5 to 10% by mass, from the viewpoint of suppressing the precipitation of the charge transporting organic compound and ensuring a sufficient film thickness. The so-called solid component refers to the components contained in the coating except the solvent. The aforementioned solvent may be used alone or in combination of two or more.

[Other components] The charge transport coating of the present invention may further contain an organic silane compound for the purpose of adjusting the film properties of the obtained charge transport thin film. Examples of the organic silane compound include a dialkoxysilane compound, a trialkoxysilane compound, or a tetraalkoxysilane compound. In other words, the organic silane compound is preferably a dialkoxysilane compound or a trialkoxysilane compound, and more preferably a trialkoxysilane compound. The organic silane compound may be used alone or in combination of two or more.

When the coating of the present invention contains an organic silane compound, the content of the organic silane compound in the solid component is generally about 0.1 to 50 mass %, but when considering the balance between improving the flatness of the obtained thin film or suppressing the decrease in charge transport properties, the content is preferably about 0.5 to 40 mass %, more preferably about 0.8 to 30 mass %, and even more preferably about 1 to 20 mass %.

The charge transport coating of the present invention may also contain an amine compound from the viewpoint of obtaining a highly uniform coating by dissolving the charge transport organic compound or admixture in a solvent. The content of the amine compound is usually about 0.1 to 50% by mass in the solid component.

The preparation method of the charge transport coating is not particularly limited, but for example, a method of adding the charge transport organic compound and the blend, and other components as necessary, to an organic solvent in any order or simultaneously. In addition, if there are plural organic solvents, each component is first dissolved in one solvent in sequence or simultaneously, and other solvents may be added thereto, or each component may be dissolved in a mixed solvent of plural organic solvents in sequence or simultaneously.

The charge transport coating of the present invention is preferably prepared by dissolving each component in an organic solvent and then filtering using a sub-micron filter, etc., from the viewpoint of obtaining a flatter and higher-quality thin film with good reproducibility.

The viscosity of the charge transport coating of the present invention is usually 1~50mPa･s at 25℃. In addition, the surface tension of the charge transport coating of the present invention is usually 20~50mN/m at 25℃. The viscosity is the value measured by TVE-25 type viscometer manufactured by Toki Industry Co., Ltd. The surface tension is the value measured by CBVP-Z type automatic surface tension meter manufactured by Kyowa Interface Science Co., Ltd. The viscosity and surface tension of the coating can be adjusted by changing the aforementioned solvent type or the ratio thereof, the solid component concentration, etc., taking into account various factors such as the desired film thickness.

[Charge transport film] The charge transport film of the present invention can be formed by coating the charge transport coating of the present invention on a substrate and firing it.

As the coating method, there can be cited dipping method, rotary coating method, transfer printing method, roll coating method, brush coating method, inkjet method, spray method, slit coating method, etc., but it is not limited to these. It is preferable to adjust the viscosity and surface tension of the coating according to the coating method.

Furthermore, the firing environment of the charge transport coating after application is not particularly limited. Not only can it be an atmospheric environment, but a uniform film surface and a thin film with charge transport properties can also be obtained in an inert gas such as nitrogen or in a vacuum. Usually, by firing the coating in an atmospheric environment, a thin film with higher charge transport properties can be obtained with excellent reproducibility.

The firing temperature is usually appropriately set within the range of about 100 to 260°C, taking into account the purpose of the obtained thin film, the degree of charge transport properties given to the obtained thin film, the type of solvent or the boiling point, etc. In addition, in order to achieve a more uniform film formation during firing or to allow a reaction on a substrate, a temperature change of two or more stages may be added, and heating may be performed using an appropriate machine such as a heating plate or an oven.

The film thickness of the charge transport film is not particularly limited, but when used as a functional layer between the anode and the light-emitting layer such as a hole injection layer, a hole transport layer, or a hole injection and transport layer of an organic EL element, 5 to 300 nm is preferred. As a method of changing the film thickness, there can be cited methods such as changing the solid component concentration in the coating or changing the amount of liquid on the substrate during coating.

Although the charge transport thin film of the present invention can be formed by the method described above, it is preferred that the charge transport thin film be formed inside the partition wall of a substrate with the partition wall by using the charge transport coating of the present invention.

The substrate with the partition wall is not particularly limited as long as it is a substrate formed with a predetermined pattern by a known photolithography method. In addition, there are usually a plurality of openings defined by the partition wall on the substrate. The size of the opening is usually 100 to 210 μm on the long side, 40 μm×100 μm on the short side, and the land angle is 20 to 80°. The material of the substrate is not particularly limited, but examples thereof include indium tin oxide (ITO) used as an anode material for electronic components, transparent electrode materials represented by indium zinc oxide (IZO); metal anode materials represented by metals such as aluminum, gold, silver, copper, indium, etc., or alloys thereof; polymer anode materials such as polythiophene derivatives or polyaniline derivatives having high charge transport properties, etc., and those that can be planarized are preferred.

After the charge transport coating of the present invention is applied to the partition wall of the substrate with the partition wall by inkjet method, the pressure is reduced, and further heating is performed as necessary, and the solvent is removed from the charge transport coating applied to the partition wall to produce a charge transport thin film, and a substrate with a charge transport thin film can be produced. When other functional films are laminated on the charge transport thin film, electronic components such as organic EL components can be produced. At this time, the environment during inkjet coating is not particularly limited, and can be any of an atmospheric environment, an inert gas environment such as nitrogen, and a reduced pressure environment.

The decompression degree (vacuum degree) during decompression is not particularly limited, but is usually below 1,000 Pa, preferably below 100 Pa, more preferably below 50 Pa, more preferably below 25 Pa, and more preferably below 10 Pa. The decompression time is not particularly limited, but is only about 0.1 to 60 minutes, preferably about 1 to 30 minutes. The conditions for firing (heating) are the same as the above conditions.

According to the method described above, the coating creeping up inside the partition wall can be effectively suppressed. Specifically, as the later-described accumulation index, it is usually 83% or more, preferably 86% or more, more preferably 89% or more, more preferably 92% or more, and more preferably 95% or more. The accumulation index can be obtained by the formula (B/A)×100(%), when the partition wall (bank) width is A(μm), the film thickness of the charge transport film in the center of the partition wall (bank) is B(μm), and the film thickness range of +10% is B(μm).

[Organic EL element] The organic EL element of the present invention has a pair of electrodes, and between these electrodes, there is a functional layer composed of the charge transporting thin film of the present invention.

As representative structures of organic EL elements, the following (a) to (f) can be cited, but are not limited thereto. In addition, for the following structures, an electron blocking layer can be provided between the light-emitting layer and the anode, and a hole (hole) blocking layer can be provided between the light-emitting layer and the cathode, as necessary. In addition, the hole injection layer, the hole transport layer, or the hole injection transport layer can also function as an electron blocking layer, and the electron injection layer, the electron transport layer, or the electron injection transport layer can also function as a hole blocking layer. And any functional layer can be provided between the layers as necessary. (a) Anode/hole injection layer/hole transport layer/luminescent layer/electron transport layer/electron injection layer/cathode (b) Anode/hole injection layer/hole transport layer/luminescent layer/electron injection transport layer/cathode (c) Anode/hole injection transport layer/luminescent layer/electron transport layer/electron injection layer/cathode (d) Anode/hole injection transport layer/luminescent layer/electron injection transport layer/cathode (e) Anode/hole injection layer/hole transport layer/luminescent layer/cathode (f) Anode/hole injection transport layer/luminescent layer/cathode

The so-called "hole injection layer", "hole transport layer" and "hole injection and transport layer" refer to layers formed between the light-emitting layer and the anode, and have the function of transporting holes from the anode to the light-emitting layer. When there is only one layer of hole transport material between the light-emitting layer and the anode, this is the "hole injection and transport layer". When there are two or more layers of hole transport material between the light-emitting layer and the anode, the layer closer to the anode is the "hole injection layer" and the other layers are the "hole transport layer". In particular, a thin film that not only has excellent hole acceptance from the anode but also has excellent hole injection properties to the hole transport (light-emitting) layer is used for the hole injection (transport) layer.

The so-called "electron injection layer", "electron transport layer" and "electron injection transport layer" refer to layers formed between the light-emitting layer and the cathode, and have the function of transporting electrons from the cathode to the light-emitting layer. If only one layer of electron transport material is provided between the light-emitting layer and the cathode, this is the "electron injection transport layer". If two or more layers of electron transport material are provided between the light-emitting layer and the cathode, the layer closer to the cathode is the "electron injection layer" and the other layers are the "electron transport layer".

The so-called "luminescent layer" is an organic layer with luminescent function. When a doping system is used, it contains a host material and a doping material. In this case, the host material mainly has the function of promoting the recombination of electrons and holes, so that the excitons are confined in the luminescent layer, and the doping material has the function of efficiently making the excitons obtained by recombination emit light. In the case of phosphorescent elements, the host material mainly has the function of confining the excitons generated in the doping in the luminescent layer.

The charge transport film of the present invention can be used as a functional layer disposed between the anode and the light-emitting layer of an organic EL element, and is more suitable as a hole injection layer, a hole transport layer, or a hole injection and transport layer. It is more suitable as a hole injection layer.

When an organic EL element is produced using the charge transport coating of the present invention, the materials used and the production method are as shown below, but are not particularly limited to these.

An example of a method for producing an organic EL element having a hole injection layer formed of a charge transporting thin film obtained from the charge transporting coating of the present invention is shown below. In addition, the electrode is preferably cleaned with alcohol, pure water, etc., or surface treated in advance by UV ozone treatment, oxygen-plasma treatment, etc., within a range that does not adversely affect the electrode.

On the anode substrate, a hole injection layer is formed by using the charge transport coating of the present invention by the aforementioned method. This is introduced into a vacuum evaporation device, and the hole transport layer, the luminescent layer, the electron transport layer/hole blocking layer, the electron injection layer, and the cathode metal are evaporated in sequence. Alternatively, for this method, instead of forming the hole transport layer and the luminescent layer by evaporation, a hole transport layer forming composition containing a hole transporting polymer and a luminescent layer forming composition containing a luminescent polymer are used to form these layers by a wet process. In addition, an electron blocking layer can be provided between the luminescent layer and the hole transport layer as necessary.

As the aforementioned anode material, transparent electrodes represented by ITO and IZO, or metals represented by aluminum, or metal anodes composed of such alloys, preferably those that undergo planarization treatment, can be cited. Polythiophene derivatives or polyaniline derivatives having high charge transport properties can also be used. In addition, as other metals constituting the metal anode, gold, silver, copper, indium, or alloys thereof can be cited, but are not limited thereto.

As materials for forming the aforementioned hole transport layer, there can be cited triarylamines such as (triphenylamine) dimer derivatives, [(triphenylamine) dimer] spirodimer, N,N'-bis(naphthalene-1-yl)-N,N'-bis(phenyl)-benzidine (α-NPD), 4,4',4"-tris[3-methylphenyl(phenyl)amino]triphenylamine (m-MTDATA), 4,4',4"-tris[1-naphthalene(phenyl)amino]triphenylamine (1-TNATA), and oligothiophenes such as 5,5"-bis-{4-[bis(4-methylphenyl)amino]phenyl}-2,2':5',2"-terthiophene (BMA-3T).

Examples of materials for forming the aforementioned light-emitting layer include metal complexes such as aluminum complexes of 8-hydroxyquinoline, metal complexes of 10-hydroxybenzo[h]quinoline, bis(phenylene glycol)benzene derivatives, bis(phenylene glycol)aryl derivatives, metal complexes of (2-hydroxyphenyl)benzothiazole, and low molecular weight light-emitting materials such as silole derivatives; and systems in which light-emitting materials and electron transfer materials are mixed in polymer compounds such as poly(p-phenylene glycol), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene glycol], poly(3-alkylthiophene), and polyvinylcarbazole, but the present invention is not limited to these.

When the luminescent layer is formed by evaporation, it may be co-evaporated with a luminescent adduct. Examples of the luminescent adduct include metal complexes such as tris(2-phenylpyridine)iridium(III) (Ir(ppy) ₃ ), naphthacene derivatives such as rubrene, quinacridone derivatives, and condensed polycyclic aromatic rings such as perylene, but the present invention is not limited thereto.

Examples of materials for forming the electron transport layer/hole blocking layer include oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, phenylquinoxaline derivatives, benzimidazole derivatives, pyrimidine derivatives, and the like, but the present invention is not limited thereto.

Examples of materials for forming the electron injection layer include metal oxides such as lithium oxide (Li ₂ O), magnesium oxide (MgO), and aluminum oxide (Al ₂ O ₃ ), and metal fluorides such as lithium fluoride (LiF) and sodium fluoride (NaF), but are not limited thereto.

Examples of the cathode material include aluminum, magnesium-silver alloy, aluminum-lithium alloy, etc., but the present invention is not limited thereto.

Examples of materials for forming the electron blocking layer include bis(phenylpyrazole)iridium, but the material is not limited thereto.

Examples of the hole transporting polymer include poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(N,N'-bis{p-butylphenyl}-1,4-diaminophenylene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(N,N'-bis{p-butylphenyl}-1,1'-biphenylene-4,4-diamine)], poly[(9,9-bis{1'-penten-5'-yl}fluorenyl-2,7-diyl)-co-(N,N'-bis{p-butylphenyl}-1,4-diaminophenylene)], poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine]-terminated With Polysilsesquioxane, poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)], etc.

Examples of the aforementioned luminescent polymer include polyfluorene derivatives such as poly(9,9-dialkylfluorene) (PDAF), polyphenylene vinylene derivatives such as poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene) (MEH-PPV), polythiophene derivatives such as poly(3-alkylthiophene) (PAT), and polyvinylcarbazole (PVCz).

The materials constituting the anode and cathode and the layers formed therebetween are different depending on whether a device having a bottom emission structure or a top emission structure is manufactured, so appropriate materials are selected in consideration of this point.

Generally, in bottom emission devices, a transparent anode is used on the substrate side to extract light from the substrate side, and in top emission devices, a reflective anode made of metal is used to extract light from the transparent electrode (cathode) side opposite to the substrate. Therefore, for example, for the anode material, when manufacturing bottom emission devices, transparent anodes such as ITO are used, and when manufacturing top emission devices, reflective anodes such as Al/Nd are used.

The organic EL element of the present invention can be sealed with a water scavenger or the like as necessary in accordance with a prescribed method to prevent degradation of the characteristics.

As described above, the charge transport film of the present invention can be used as a functional layer of an organic EL element, but can also be used as a functional layer of other electronic elements such as organic photoelectric conversion elements, organic thin film solar cells, organic calcium refractive index photoelectric conversion elements, organic integrated circuits, organic electric field effect transistors, organic thin film transistors, organic light-emitting transistors, organic optical detectors, organic photoreceptors, organic electric field extinction elements, light-emitting electrochemical cells, quantum dot light-emitting diodes, quantum lasers, organic laser diodes, and organic plasma light-emitting elements. [Examples]

The present invention will be described in more detail below with reference to synthesis examples, production examples, embodiments and comparative examples, but the present invention is not limited to the following embodiments.

The apparatus used is shown below. (1) MALDI-TOF-MS: autoflex III smartbeam manufactured by Bruker (2) ¹ H-NMR: JNM-ECP300 FT NMR SYSTEM manufactured by NEC Corporation (3) Substrate cleaning: Substrate cleaning device manufactured by Choshu Industry Co., Ltd. (reduced pressure plasma method) (4) Coating application: Rotary coater MS-A100 manufactured by Mikasa Co., Ltd. (5) Film thickness measurement and surface shape measurement: Surf coder ET-4000A micro-shape measuring machine manufactured by Kosaka Laboratory (6) Component manufacturing: Multi-function evaporation device system C-E2L1G1-N manufactured by Choshu Industry Co., Ltd. (7) Component current density measurement: Multi-channel made by EHCIVL measuring device (8) Inkjet device: Cluster Technology Co., Ltd.'s dedicated Driver WAVE BUILDER (model: PIJD-1), inkjetlado with camera observation device, Automatic stage Inkjet Designer, and inkjet head PIJ-25NSET

The reagents used are as follows. MMA: methyl methacrylate HEMA: 2-hydroxyethyl methacrylate HPMA: 4-hydroxyphenyl methacrylate HPMA-QD: a compound synthesized by the condensation reaction of 1 mol of 4-hydroxyphenyl methacrylate and 1.1 mol of 1,2-naphthoquinone-2-bis(azolozide)-5-sulfonyl chloride CHMI: N-cyclohexylmaleimide PFHMA: 2-(perfluorohexyl)ethyl methacrylate MAA: methyl acrylate AIBN: α,α’-azobis(isobutyronitrile) QD1: a compound synthesized by the condensation reaction of 1 mol of 4-hydroxyphenyl methacrylate and 1.1 mol of 1,2-naphthoquinone-2-bis(azolozide)-5-sulfonyl chloride Compound synthesized by the condensation reaction of α,α,α’-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene 1 mol and 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride 1.5 mol GT-401: Butanetetracarboxylic acid tetra(3,4-epoxycyclohexylmethyl) modified ε-caprolactone (trade name: Epolide GT-401, manufactured by Daicellu Co., Ltd.) PGME: Propylene glycol monomethyl ether PGMEA: Propylene glycol monomethyl ether acetate CHN: Cyclohexanone TMAH: Tetramethylammonium hydroxide

[1] Preparation of a substrate with a partition wall (bank) (1) Synthesis of acrylic polymer [Synthesis Example 1-1] MMA (10.0 g), HEMA (12.5 g), CHMI (20.0 g), HPMA (2.50 g), MAA (5.00 g) and AIBN (3.20 g) were dissolved in PGME (79.8 g) and reacted at 60-100°C for 20 hours to obtain an acrylic polymer P1 solution (solid content concentration 40% by mass). The Mn of the acrylic polymer P1 was 3,700 and the Mw was 6,100.

[Synthesis Example 1-2] HPMA-QD (2.50 g), PFHMA (7.84 g), MAA (0.70 g), CHMI (1.46 g) and AIBN (0.33 g) were dissolved in CHN (51.3 g) and reacted by stirring at 110°C for 20 hours to obtain an acrylic polymer P2 solution (solid content concentration 20% by mass). The Mn of the acrylic polymer P2 was 4,300 and the Mw was 6,300.

Furthermore, the number average molecular weight (Mn) and weight average molecular weight (Mw) of the acrylic polymers P1 and P2 can be measured by gel permeation chromatography (GPC) under the following conditions. ･Chromatograph: GPC apparatus LC-20AD manufactured by Shimadzu Corporation ･Column: Shodex KF-804L and 803L (manufactured by Showa Denko Co., Ltd.) and TSK-GEL (manufactured by Tosoh Corporation) connected in series ･Column temperature: 40°C ･Detector: UV detector (254nm) and RI detector ･Eluent: Tetrahydrofuran ･Column flow rate: 1 mL/min

(2) Preparation of positive photosensitive resin composition [Preparation Example 1] Acrylic polymer P1 solution (5.04 g), acrylic polymer P2 solution (0.05 g), QD1 (0.40 g), GT-401 (0.09 g) and PGMEA (6.42 g) were mixed and stirred at room temperature for 3 hours to form a uniform solution, thereby obtaining a positive photosensitive resin composition.

(3) Preparation of a substrate with a partition wall (bank) [Preparation Example 2] The positive photosensitive resin composition obtained in Preparation Example 1 was applied to an ITO-glass substrate that had been ozone-cleaned for 10 minutes using UV-312 manufactured by Technovision Co., Ltd. using a rotary coater, and the substrate was pre-baked on a heating plate (100°C, 120 seconds) to form a film with a thickness of 1.2 μm. On the film, a rectangular pattern with a long side of 200 μm and a short side of 100 μm was drawn through a photomask, and the film was exposed to ultraviolet light with a wavelength of 365 nm at 175 mJ/ ^cm2 using an ultraviolet irradiation device PLA-600FA manufactured by Canon Co., Ltd. After that, the film was immersed in a 1.0 mass % TMAH aqueous solution for 120 seconds for development, and then washed with ultrapure water for 20 seconds. Next, the film formed with the rectangular pattern was baked (230°C, 30 minutes) to harden it until a substrate with partition walls was obtained.

[2] Synthesis of Charge Transporting Organic Compounds [Synthesis Example 2-1] Synthesis of Aniline Derivative A

After placing 1.00 g of N1-(4-aminophenyl)benzene-1,4-diamine, 8.89 g of 2-bromo-9-phenyl-9H-carbazole, 112 mg of sodium acetate and 3.47 g of tert-butoxysodium in a flask, the flask was substituted with nitrogen. Then, 30 mL of toluene and 2.75 mL of a pre-prepared toluene solution of di-tert-butyl(phenyl)phosphine (concentration 81.0 g/L) were added and stirred at 90°C for 6 hours. After stirring, the reaction mixture was cooled to room temperature, and the cooled reaction mixture, toluene and ion exchange water were mixed and separated. The obtained organic layer was dried with sodium sulfate and concentrated. The concentrated solution was filtered through silica gel, 0.2 g of activated carbon was added to the obtained filtrate, and stirred at room temperature for 30 minutes. Afterwards, the activated carbon was removed by filtration and the filtrate was concentrated. The concentrated solution was dropped into a mixed solvent of methanol and ethyl acetate (500 mL/500 mL), and the obtained slurry was stirred at room temperature overnight, then the slurry was filtered and the filtrate was recovered. The obtained filtrate was dried to obtain the target aniline derivative A (yield 5.88 g, yield 83%). ¹ H-NMR (500MHz, THF-d ₈ ) δ [ppm]: 8.02-8.10(m, 10H), 7.48-7.63(m, 22H), 7.28-7.39(m, 14H), 7.19-7.24(m, 10H), 7.02-7.09(m, 12H). MALDI-TOF-MS m/Z found: 1404.88 ([M] ⁺ calcd: 1404.56).

[Synthesis Example 2-2] Synthesis of Aniline Derivative B According to the method described in International Publication No. 2015/050253, an aniline derivative B represented by the following formula was synthesized.

[3] Synthesis of blends [Synthesis Example 3-1] Synthesis of aryl sulfonate C According to the method described in International Publication No. 2017/217455, aryl sulfonate C represented by the following formula was synthesized.

[Synthesis Example 3-2] Synthesis of aryl sulfonate D First, according to the method described in International Publication No. 2015/111654, the aryl sulfonic acid D' represented by the following formula was synthesized. To the aryl sulfonic acid D' (4.97 g, 10 mmol), thionyl chloride (25 g) and N,N-dimethylformamide (0.4 mL) as a catalyst were added, and after heating and refluxing for 1 hour, thionyl chloride was removed to obtain a solid containing the acyl chloride of the aryl sulfonic acid D'. This compound does not need to be purified above and can be used directly in the next step. The above-mentioned solid chloroform (30 mL) and pyridine (20 mL) were added, and 6.24 g (60 mmol) of propylene glycol monoethyl ether was added at 0°C. After heating to room temperature, stirring was performed for 1.5 hours. After distilling off the solvent, water was added, and extraction was performed with ethyl acetate. The organic layer was dried with sodium sulfate. After filtration and concentration, the obtained crude product was purified by silica gel column chromatography (hexane/ethyl acetate) to obtain 1.32 g of aryl sulfonate D as a white solid (yield 20% (second-stage yield from aryl sulfonic acid D')). The results of ¹ H-NMR and LC/MS are shown below. ¹ H-NMR (500MHz, CDCl ₃ ): δ 0.89-0.95(m, 6H), 1.34 and 1.39(a pair of d, J=6.5Hz, 6H), 3.28-3.50(m, 8H), 4.81-4.87(m, 2H), 7.26(s, 1H), 8.22( d, J=9.0Hz, 1H), 8.47(s, 1H), 8.54(d, J=9.0Hz, 1H), 8.68(s, 1H). LC/MS (ESI ⁺ ) m/z; 687 [M+NH ₄ ] ⁺

[4] Preparation of charge transport coating [Example 1-1] 5.00 g of triethylene glycol butyl methyl ether, 3.00 g of diisopropyl malonate and 2.00 g of dimethyl phthalate were added to 0.183 g of aniline derivative A, 0.325 g of aryl sulfonate C and 0.018 g of F4TCNQ, and the mixture was stirred at room temperature to dissolve. The resulting solution was filtered with a PTFE syringe filter with a pore size of 0.2 μm to prepare charge transport coating A.

[Example 1-2] 5.00 g of triethylene glycol butyl methyl ether, 3.00 g of diisopropyl malonate and 2.00 g of dimethyl phthalate were added to 0.257 g of aniline derivative A, 0.245 g of aryl sulfonate D and 0.025 g of F4TCNQ, and the mixture was stirred at room temperature to dissolve. The resulting solution was filtered with a PTFE syringe filter having a pore size of 0.2 μm to prepare a charge transport coating B.

[Example 1-3] 5.00 g of triethylene glycol butyl methyl ether, 3.00 g of diisopropyl malonate and 2.00 g of dimethyl phthalate were added to 0.184 g of aniline derivative A, 0.327 g of aryl sulfonate C and 0.015 g of DDQ, and the mixture was stirred at room temperature to dissolve. The resulting solution was filtered with a PTFE syringe filter with a pore size of 0.2 μm to prepare a charge transport coating C.

[Example 1-4] 5.00 g of triethylene glycol butyl methyl ether, 3.00 g of diisopropyl malonate and 2.00 g of dimethyl phthalate were added to 0.183 g of aniline derivative B, 0.325 g of aryl sulfonate C and 0.018 g of F4TCNQ, and the mixture was stirred at room temperature to dissolve. The resulting solution was filtered with a PTFE syringe filter having a pore size of 0.2 μm to prepare a charge transport coating D.

[Example 1-5] 5.00 g of triethylene glycol butyl methyl ether, 3.00 g of diisopropyl malonate and 2.00 g of dimethyl phthalate were added to 0.257 g of aniline derivative B, 0.245 g of aryl sulfonate D and 0.025 g of F4TCNQ, and the mixture was stirred at room temperature to dissolve. The resulting solution was filtered with a PTFE syringe filter having a pore size of 0.2 μm to prepare a charge transport coating E.

[Example 1-6] 5.00 g of triethylene glycol butyl methyl ether, 3.00 g of diisopropyl malonate and 2.00 g of dimethyl phthalate were added to 0.184 g of aniline derivative B, 0.327 g of aryl sulfonate C and 0.015 g of DDQ, and the mixture was stirred at room temperature to dissolve. The resulting solution was filtered with a PTFE syringe filter having a pore size of 0.2 μm to prepare a charge transport coating F.

[Comparative Example 1-1] 5.00 g of triethylene glycol butyl methyl ether, 3.00 g of diisopropyl malonate and 2.00 g of dimethyl phthalate were added to 0.479 g of aniline derivative A and 0.047 g of F4TCNQ, and the mixture was stirred at room temperature to dissolve. The resulting solution was filtered with a PTFE syringe filter having a pore size of 0.2 μm to prepare a charge transport coating G.

[Comparative Example 1-2] 5.00 g of triethylene glycol butyl methyl ether, 3.00 g of diisopropyl malonate and 2.00 g of dimethyl phthalate were added to 0.487 g of aniline derivative A and 0.039 g of DDQ, and the mixture was stirred at room temperature to dissolve. The resulting solution was filtered with a PTFE syringe filter with a pore size of 0.2 μm to prepare a charge transport coating H.

[Comparative Example 1-3] 5.00 g of triethylene glycol butyl methyl ether, 3.00 g of diisopropyl malonate and 2.00 g of dimethyl phthalate were added to 0.479 g of aniline derivative B and 0.047 g of F4TCNQ, and the mixture was stirred at room temperature to dissolve. The resulting solution was filtered with a PTFE syringe filter having a pore size of 0.2 μm to prepare a charge transport coating I.

[Comparative Example 1-4] 5.00 g of triethylene glycol butyl methyl ether, 3.00 g of diisopropyl malonate and 2.00 g of dimethyl phthalate were added to 0.487 g of aniline derivative B and 0.039 g of DDQ, and the mixture was stirred at room temperature to dissolve. The resulting solution was filtered with a PTFE syringe filter with a pore size of 0.2 μm to prepare a charge transport coating J.

[Comparative Example 1-5] 5.00 g of triethylene glycol butyl methyl ether, 3.00 g of diisopropyl malonate and 2.00 g of dimethyl phthalate were added to 0.180 g of the polymer H1 (TFB polymer, LT-N148 manufactured by Luminescence Technology) represented by the following formula (H1), 0.120 g of aryl sulfonate C and 0.002 g of F4TCNQ, and the mixture was stirred at room temperature to dissolve. The resulting solution was filtered with a PTFE syringe filter having a pore size of 0.2 μm to prepare a charge transport coating K.

[Comparative Example 1-6] 5.00 g of triethylene glycol butyl methyl ether, 3.00 g of diisopropyl malonate and 2.00 g of dimethyl phthalate were added to 0.180 g of polymer H1, 0.120 g of aryl sulfonate D and 0.002 g of F4TCNQ, and stirred at room temperature to dissolve. The resulting solution was filtered with a PTFE syringe filter with a pore size of 0.2 μm to prepare a charge transport coating L.

[5] Fabrication and property evaluation of single-layer devices (SLD) [Example 2-1] After applying the charge transport coating A to an ITO substrate using a rotary coater, the coating was dried at 120°C for 1 minute in the atmosphere and then sintered at 200°C for 15 minutes to form a uniform thin film with a thickness of 50 nm on the ITO substrate. As an ITO substrate, a 25 mm × 25 mm × 0.7 t glass substrate with a patterned ITO film of 150 nm in thickness formed on the surface was used. Before use, impurities on the surface were removed using an O ₂ plasma cleaning device (150 W, 30 seconds). Next, for the ITO substrate with the thin film formed, an evaporation device (vacuum degree 1.0×10 ^-5 Pa) was used to form an aluminum film of 80 nm at 0.2 nm/sec to produce a single-layer device A. In order to prevent the degradation of characteristics due to the influence of oxygen, water, etc. in the air, the components were sealed with a sealing substrate and their characteristics were evaluated. The sealing was performed according to the following procedure. In a nitrogen environment with an oxygen concentration of less than 2ppm and a dew point of less than -76°C, the components were placed between the sealing substrates, and the sealing substrates were bonded together with an adhesive (Moresco Moisture Cut WB90US(P) manufactured by MORESCO Co., Ltd.). At this time, a water scavenger (HD-071010W-40 manufactured by Dynic Co., Ltd.) was placed in the sealing substrate together with the components. The bonded sealing substrates were irradiated with UV light (wavelength: 365nm, irradiation amount: 6,000mJ/ ^cm2 ), then subjected to a heat treatment (annealing) at 80°C for 1 hour to cure the adhesive.

[Example 2-2] A single-layer element B is manufactured in the same manner as in Example 2-1 except that the charge transport coating A is replaced with the charge transport coating B.

[Example 2-3] A single-layer element C is manufactured in the same manner as in Example 2-1 except that the charge transport coating A is replaced with the charge transport coating C.

[Example 2-4] A single-layer device D was produced in the same manner as Example 2-1 except that the charge transport coating D was used instead of the charge transport coating A and the sintering was performed at 230°C for 15 minutes.

[Example 2-5] A single-layer device E was produced in the same manner as in Example 2-1 except that the charge transport coating E was used instead of the charge transport coating A and the sintering was performed at 230°C for 15 minutes.

[Example 2-6] A single-layer device F was produced in the same manner as in Example 2-1 except that the charge transport coating F was used instead of the charge transport coating A and the sintering was performed at 230°C for 15 minutes.

[Comparative Example 2-1] A single-layer device G was manufactured in the same manner as in Example 2-1 except that the charge transport coating G was used instead of the charge transport coating A.

[Comparative Example 2-2] A single-layer device H was manufactured in the same manner as in Example 2-1 except that the charge transport coating H was used instead of the charge transport coating A.

[Comparative Example 2-3] A single-layer device I was produced in the same manner as in Example 2-1 except that the charge transport coating I was used instead of the charge transport coating A and the sintering was performed at 230°C for 15 minutes.

[Comparative Example 2-4] A single-layer device J was produced in the same manner as in Example 2-1 except that the charge transport coating J was used instead of the charge transport coating A and the sintering was performed at 230°C for 15 minutes.

The current density of the manufactured single-layer device when driven at 3 V was measured. The results are shown in Table 1.

As shown in Table 1, the thin film made from the charge transport coating of the present invention exhibits good charge transport properties.

[6] Fabrication and property evaluation of single-hole device (HOD) For the following examples and comparative examples, the same ITO substrate as described above was used. [Example 3-1] After the charge transport coating A was applied to the ITO substrate using a rotary coater, it was dried at 120°C for 1 minute in the atmosphere and then sintered at 200°C for 15 minutes to form a 50nm uniform thin film on the ITO substrate. On top of it, a thin film of α-NPD and aluminum was sequentially laminated using an evaporation device (vacuum degree 1.0× ^10-5 Pa) to obtain a single-hole device A. The evaporation was carried out at an evaporation rate of 0.2nm/sec. The film thicknesses of the α-NPD and aluminum thin films were 30nm and 80nm, respectively. After the device was sealed in the same manner as in Example 2-1, the characteristics were evaluated.

[Example 3-2] A single-hole device B was produced in the same manner as in Example 3-1 except that the charge transporting coating material B was used instead of the charge transporting coating material A.

[Example 3-3] Except that charge transport coating C is used instead of charge transport coating A, a single hole element C is produced in the same manner as in Example 3-1.

[Example 3-4] A single-hole device D was produced in the same manner as in Example 3-1 except that the charge transporting coating D was used instead of the charge transporting coating A and the device was fired at 230°C for 15 minutes.

[Example 3-5] A single-hole device E was produced in the same manner as in Example 3-1 except that the charge transport coating E was used instead of the charge transport coating A and the sintering was performed at 230°C for 15 minutes.

[Example 3-6] A single-hole device F was produced in the same manner as in Example 3-1 except that charge transport coating F was used instead of charge transport coating A and sintering was performed at 230°C for 15 minutes.

[Comparative Example 3-1] A single-hole device G was produced in the same manner as in Example 3-1 except that the charge transporting coating G was used instead of the charge transporting coating A.

[Comparative Example 3-2] A single-hole device H was produced in the same manner as in Example 3-1 except that the charge transporting coating material H was used instead of the charge transporting coating material A.

[Comparative Example 3-3] A single-hole device I was produced in the same manner as in Example 3-1 except that the charge transport coating I was used instead of the charge transport coating A and the sintering was performed at 230°C for 15 minutes.

[Comparative Example 3-4] A single-hole device J was produced in the same manner as in Example 3-1 except that the charge transport coating J was used instead of the charge transport coating A and the sintering was performed at 230°C for 15 minutes.

The current density of the manufactured single-hole device was measured when it was driven at 3 V. The results are shown in Table 2.

As shown in Table 2, the thin film made of the charge transport coating of the present invention exhibits good hole injection properties for α-NPD which is often used as a hole transport layer.

[7] Fabrication and Characteristic Evaluation of Organic EL Components For the following examples and comparative examples, the same ITO substrate as described above was used. [Example 4-1] After applying the charge transport coating A to the ITO substrate using a rotary coater, it was dried at 120°C for 1 minute in the atmosphere and then sintered at 200°C for 15 minutes to form a 50nm uniform thin film on the ITO substrate. On top of it, α-NPD was formed into a 30nm film at 0.2nm/sec using an evaporation device (vacuum degree 1.0× ^10-5 Pa). Next, CBP and Ir(PPy) ₃ were co-evaporated. For the co-evaporation, the evaporation rate was controlled to a concentration of 6% for Ir(PPy) ₃ and the layering was to 40nm. Next, an organic EL device A was obtained by laminating thin films of tris(8-hydroxyquinoline)aluminum(III) (Alq ₃ ), lithium fluoride, and aluminum. At this time, the evaporation rate was 0.2 nm/sec for Alq ₃ and aluminum, and 0.02 nm/sec for lithium fluoride, and the film thicknesses were 20 nm, 0.5 nm, and 80 nm, respectively. The device was sealed in the same manner as in Example 2-1, and the characteristics were evaluated.

[Example 4-2] An organic EL element B was produced in the same manner as in Example 4-1 except that the charge transporting coating material B was used instead of the charge transporting coating material A.

[Example 4-3] An organic EL element C was produced in the same manner as in Example 4-1 except that the charge transporting coating C was used instead of the charge transporting coating A.

[Example 4-4] An organic EL element D was produced in the same manner as in Example 4-1 except that charge transport coating D was used instead of charge transport coating A and the sintering was performed at 230°C for 15 minutes.

[Example 4-5] An organic EL element E was produced in the same manner as in Example 4-1 except that the charge transport coating E was used instead of the charge transport coating A and the sintering was performed at 230°C for 15 minutes.

[Example 4-6] An organic EL element F was produced in the same manner as in Example 4-1 except that charge transport coating F was used instead of charge transport coating A and the sintering was performed at 230°C for 15 minutes.

[Comparative Example 4-1] An organic EL element G was produced in the same manner as in Example 4-1 except that the charge transporting coating G was used instead of the charge transporting coating A.

[Comparative Example 4-2] An organic EL element H was produced in the same manner as in Example 4-1 except that the charge transporting coating H was used instead of the charge transporting coating A.

[Comparative Example 4-3] An organic EL element I was produced in the same manner as in Example 4-1 except that the charge transport coating I was used instead of the charge transport coating A and the sintering was performed at 230°C for 15 minutes.

[Comparative Example 4-4] An organic EL element J was produced in the same manner as in Example 4-1 except that the charge transport coating J was used instead of the charge transport coating A and the sintering was performed at 230°C for 15 minutes.

The luminance of the manufactured organic EL element was measured when it was driven at 8 V. The results are shown in Table 3.

As shown in Table 3, the thin film made of the charge transport coating of the present invention exhibits high organic EL characteristics.

[7] Preparation of a substrate with a charge transporting film by inkjet coating [Example 5-1] The charge transporting coating A is diluted with a solvent to a solid content concentration of 2.3% by mass, and is ejected from the rectangular opening (film forming area) on the substrate with a partition wall prepared in Preparation Example 2 using an inkjet device. When diluting the charge transporting coating, the dilution is performed so that the composition ratio of the mixed solvent in the coating does not change. The obtained coating is then immediately dried under reduced pressure (vacuum) of less than 10Pa at room temperature for 15 minutes, and then dried at 200°C for 15 minutes at normal pressure to form a charge transporting film in the partition wall, thereby obtaining a substrate A with a charge transporting film. Furthermore, the film thickness near the center of the opening of the discharged charge transport film is 90 to 110 nm.

[Example 5-2] Except that charge transport coating B is used instead of charge transport coating A, a substrate with a charge transport thin film is prepared in the same manner as in Example 5-1.

[Example 5-3] Except that charge transport coating C is used instead of charge transport coating A, a substrate with a charge transport thin film is prepared in the same manner as in Example 5-1.

[Example 5-4] Except that charge transport coating D is used instead of charge transport coating A, a substrate with a charge transport thin film is prepared in the same manner as in Example 5-1.

[Example 5-5] Except that charge transport coating E is used instead of charge transport coating A, a substrate with a charge transport thin film is prepared in the same manner as in Example 5-1.

[Example 5-6] Except that charge transport coating F is used instead of charge transport coating A, a substrate with a charge transport thin film is prepared in the same manner as in Example 5-1.

[Comparative Example 5-1] Except that charge transport coating G is used instead of charge transport coating A, a substrate with a charge transport thin film is prepared in the same manner as in Example 5-1.

[Comparative Example 5-2] Except that charge transport coating H is used instead of charge transport coating A, a substrate with a charge transport thin film is prepared in the same manner as in Example 5-1.

[Comparative Example 5-3] Except that charge transport coating I is used instead of charge transport coating A, a substrate with a charge transport thin film is prepared in the same manner as in Example 5-1.

[Comparative Example 5-4] Substrate K with a charge transport thin film was produced in the same manner as in Example 5-1 except that charge transport coating K was used instead of charge transport coating A. However, a concave-convex structure was generated on the film surface, and a flat film could not be obtained.

[Comparative Example 5-5] A substrate L with a charge transport thin film was prepared in the same manner as in Example 5-1 except that the charge transport coating L was used instead of the charge transport coating A. However, a concave-convex structure was generated on the film surface, and a flat film could not be obtained.

The extrapolation index of the produced charge transport film was calculated. The extrapolation index is (B/A)×100(%) when the width of the rib (bank) is A(μm) and the film thickness range of the charge transport film from the center of the rib (bank) is +10% as B(μm). The results are shown in Tables 4 to 5. In Examples 5-1 to 5-3 and 5-6 and Comparative Examples 5-1 and 5-2, the extrapolation index was calculated with the short side as the rib width, and in Examples 5-4 and 5-5 and Comparative Example 5-3, the extrapolation index was calculated with the long side as the rib width.

As shown in Tables 4 and 5, the charge transport thin film formed using the charge transport coating of the present invention has good flatness and shows a high plotting index of more than 95%. On the other hand, the charge transport thin film formed using the charge transport coating of the comparative example shows a lower plotting index than the example. In addition, when the polymer H1 (Comparative Examples 5-4 and 5-5) is used, a concavo-convex structure is generated on the film surface, and a flat film cannot be obtained.

Claims (14)

A charge transport coating, which is a charge transport coating containing (A) a monodisperse charge transport organic compound of an aromatic amine derivative, (B) a blend, and (C) an organic solvent, wherein (B) the blend contains (B1) an aromatic sulfonate compound and (B2) halogenated tetracyanoquinodimethane, or contains (B1) an aromatic sulfonate compound and (B3) halogenated or cyanated benzoquinone. As for the transportable coating of claim 1, the aforementioned arylamine derivative is a tertiary arylamine compound. As in claim 2, the charge transport coating, wherein the aforementioned tertiary arylamine compound has at least one nitrogen atom, and all nitrogen atoms have a tertiary arylamine structure. As in claim 3, the charge transport coating, wherein the aforementioned tertiary arylamine compound has at least 2 nitrogen atoms, and all nitrogen atoms have a tertiary arylamine structure. The charge transport coating of claim 1, wherein the aryl sulfonate compound is represented by the following formula (B1) or (B1′);

In the formula, ^A1 is an m-valent alkyl group having 6 to 20 carbon atoms and containing one or more aromatic rings which may have a substituent, or an m-valent group derived from a compound represented by the following formula (B1a) or (B1b);

wherein ^W1 and ^W2 are independently -O-, -S-, -S(O)- or -S( _{O2)-, or -N-, -Si-, -P- or -P(O)- which may have a substituent; A2 is -O-, -S- or -NH-; A3 is or is an (n+1} ^{) -valent} aromatic group having 6 to 20 carbon atoms; ^X1 is an alkylene group having 2 to 5 carbon atoms, wherein -O-, -S- or a carbonyl group may be present between the carbon atoms of the alkylene group, and a part or all of the hydrogen atoms of the alkylene group may be further substituted by an alkyl group having 1 to 20 carbon atoms; ^X2 is a single bond, -O-, -S- or -NR-, and R is a hydrogen atom or a monovalent alkyl group having 1 to 10 carbon atoms; X ³ is a monovalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent; m is an integer satisfying 1≦m≦4; and n is an integer satisfying 1≦n≦4]. The charge transport coating of claim 5, wherein the aryl sulfonate compound is any one of the following formulas (B1-1) to (B1-3);

In the formula, R ^s1 to R ^s4 are each independently a hydrogen atom, or a linear or branched alkyl group having 1 to 6 carbon atoms, R ^s5 is a monovalent alkyl group having 2 to 20 carbon atoms which may have a substituent; A ¹¹ is an m-valent group derived from perfluorobiphenyl, A ¹² is -O- or -S-, and A ¹³ is an (n+1)-valent group derived from naphthalene or anthracene; m and n are the same as above;

In the formula, R ^s6 and R ^s7 are each independently a hydrogen atom, or a linear or branched monovalent aliphatic alkyl group, R ^s8 is a linear or branched monovalent aliphatic alkyl group, but the total number of carbon atoms of R ^s6 , R ^s7 and R ^s8 is 6 or more; A ¹⁴ may have a substituent and is an m-valent alkyl group containing one or more aromatic rings, A ¹⁵ is -O- or -S-, and A ¹⁶ is an (n+1)-valent aromatic group; m and n are the same as above;

(wherein, R ^s9 to R ^s13 are each independently a hydrogen atom, a nitro group, a cyano group, a halogen atom, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, or a halogenated alkenyl group having 2 to 10 carbon atoms; R ^s14 to R ^s17 are each independently a hydrogen atom, or a linear or branched monovalent aliphatic alkyl group having 1 to 20 carbon atoms; R ^s18 is a linear or branched monovalent aliphatic alkyl group having 1 to 20 carbon atoms, or -OR ^s19 , R ^s19 is a monovalent alkyl group having 2 to 20 carbon atoms which may have a substituent; A ¹⁷ is -O-, -S- or -NH-; A ¹⁸ is an (n+1)-valent aromatic group; n is the same as above. The charge transport coating according to any one of claims 1 to 6, wherein the (B2) halogenated tetracyanoquinodimethane is represented by the following formula (B2);

In the formula, R ^q1 to R ^q4 are each independently a hydrogen atom or a halogen atom, but at least one of them is a halogen atom. The charge transport coating according to any one of claims 1 to 6, wherein the halogenated or cyanated benzoquinone (B3) is represented by the following formula (B3);

In the formula, R ^q5 to R ^q8 are each independently a hydrogen atom, a halogen atom or a cyano group, but at least one of them is a halogen atom or a cyano group. The charge transport coating of any one of claims 1 to 6, wherein the molar ratio of the (B1) aryl sulfonate compound to the (B2) halogenated tetracyanoquinodimethane or the (B3) halogenated or cyanated benzoquinone is 0.01 to 50. A charge transport coating as claimed in any one of claims 1 to 6, wherein the molecular weight of the monodisperse charge transport organic compound is 200 to 9,000. For a charge transport coating as claimed in any one of claims 1 to 6, the organic solvent contains a low polarity organic solvent. A charge transport film, which is obtained by containing a charge transport coating as described in any one of claims 1 to 11. An organic electroluminescent element having a charge transporting film as claimed in claim 12. As in claim 13, the organic electroluminescent element, wherein the charge transporting film is a hole injection layer or a hole transporting layer.