Charge transportable ink composition

Abstract

As a charge transportable ink composition having charge transportability and high transparency in the visible light region, while forming a film excellent in flatness, stable to atmospheric exposure, provided is a charge transportable ink composition characterized by containing an amine compound represented by the following formula (P1), a charge transportable substance, and an organic solvent. (In the formula, R m represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, R n represents an alkylene group having 1 to 20 carbon atoms, an alkenylene group having 2 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, or R m is bonded to each other, and represents an alkane triyl group having 3 to 40 carbon atoms, R n an alkylene group having 1 to 20 carbon atoms, and an alkenylene group having 2 to 20 carbon atoms, and R n an alkane triyl group having 3 to 40 carbon atoms, and R m an alkylene group having 1 to 20 carbon atoms, and an alkenylene group having 2 to 20 carbon atoms, and R n an alkane triyl group having 3 to 40 carbon atoms, in the case of being bonded to -NH2 in formula (P1), is limited to forming a -CH2-NH2 group.) R m -O-R n -NH2 (P1).

Description

TECHNICAL FIELD

[0001] The present application relates to a charge transportable ink composition. BACKGROUND

[0002] An organic electroluminescence (hereinafter referred to as organic EL) element is attracting attention due to various advantages such as high contrast, energy saving, flexibility, and the like, and practical use is being promoted in the fields of displays, lighting, and the like. In the organic EL element, a plurality of functional thin films are used, and as one of them, a hole injection layer plays an important role in realizing low voltage driving and high luminance of the organic EL element by taking over the exchange of charges between an anode and a hole transport layer or a light-emitting layer.

[0003] The manufacturing method of the organic EL element is roughly divided into a dry method typified by a vapor deposition method and a wet method typified by a spin coating method, an inkjet method. If the two methods are compared from the viewpoint of the large-area of the element, the wet method can efficiently and large-area manufacture a film with high planarity compared to the dry method. Therefore, in the present, where large-area manufacturing of the organic EL element is required, it is important to provide a hole injection layer and the like with excellent functions that can be formed using the wet method.

[0004] One of the functions required for the charge transportable thin film such as the hole injection layer can be listed as high transparency in the visible light region. In terms of coloring of the charge transportable thin film, the color purity and color reproducibility of the organic EL element are reduced, and the like, and in recent years, high transparency in the visible light region is required.

[0005] In view of this, until now, various studies have been made in order to achieve high transparency in the visible light region. In Patent Literature 1, by using a composition containing metal oxide nanoparticles, formation of a charge transportable thin film with high transparency in the visible light region is achieved.

[0006] On the other hand, for the charge transportable thin film such as the hole injection layer, in addition to excellent charge transport characteristics, high transparency in the visible light region, the planarity of the film, the stability of the ink composition are required. In Non-Patent Literature 1, it is shown that by reducing the surface roughness of the film, the characteristics of the organic EL element are improved. In addition, the charge transportable ink is generally susceptible to the influence of oxygen, moisture, and the like, and it is possible that the performance changes due to oxidation, decomposition, and the like of the compounds in the ink. Therefore, from the viewpoint of reliability, it is important for the charge transportable ink to be stable to atmospheric exposure.

[0007] PRIOR ART DOCUMENTS

[0008] PATENT LITERATURE

[0009] Patent Literature 1: International Publication No. 2018 / 135582

[0010] NON-PATENT LITERATURE

[0011] Non-patent literature 1: Korean Journal of Chemical Engineering 2005, Vol. 22, pp. 643-647 SUMMARY

[0012] PROBLEMS TO BE SOLVED BY THE INVENTION

[0013] With the development of the organic EL field in recent years, the performance required for a functional thin film including a hole injection layer, which can be formed by a wet film formation method, is increasing.

[0014] The present invention was completed in view of the above background, and aims to provide a charge transportable ink composition having charge transportability, while forming a film excellent in flatness, and stable to atmospheric exposure.

[0015] MEANS FOR SOLVING THE PROBLEMS

[0016] The present inventors conducted intensive studies, and as a result, found that in a charge transportable ink composition including a charge transportable substance and an organic solvent, like the composition disclosed in the above-described patent literature 1, in the case where an amine compound is contained, by using an amine compound having a specific structure, the flatness of a charge transportable thin film is improved, and in addition, the stability of the ink to atmospheric exposure is improved, and completed the present invention.

[0017] That is, the present invention provides the following charge transportable ink composition.

[0018] 1. A charge transportable ink composition, characterized by containing: an amine compound represented by the following formula (P1), a charge transportable substance, and an organic solvent,

[0019] [Chemical Formula 1]

[0020] R m -O-R n -NH2 (P1)

[0021] In the formula, R m represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, R n represents an alkylene group having 1 to 20 carbon atoms, an alkenylene group having 2 to 20 carbon atoms, or an arylene group having 6 to 20 carbon atoms, or R m and R n are mutually bonded, and represent an alkane triyl group having 3 to 40 carbon atoms, R n an alkylene group having 1 to 20 carbon atoms, and an alkenylene group having 2 to 20 carbon atoms of R m and R nalkanetriyl group in the case where it is bonded to -NH2in formula (P1) is limited to form a -CH2-NH2group.

[0022] 2. The charge transportable ink composition according to 1, wherein the R m is an alkyl group having 1 to 20 carbon atoms, the R n is an alkylene group having 1 to 20 carbon atoms.

[0023] 3. The charge transportable ink composition according to 1 or 2, wherein the charge transportable substance is a polythiophene derivative containing a repeating unit represented by the following formula (1) or an amine adduct thereof,

[0024] [Chemical Formula 2]

[0025]

[0026] in the formula, R 1 and R 2 independently of each other are a hydrogen atom, an alkyl group having 1 to 40 carbon atoms, a fluoroalkyl group having 1 to 40 carbon atoms, an alkoxy group having 1 to 40 carbon atoms, a fluoroalkoxy group having 1 to 40 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, -O-[Z-O] p -R e or a sulfonic acid group, or are -O-Y-O- formed by bonding of R 1 and R 2 , Y being an alkylene group having 1 to 40 carbon atoms which can contain an ether bond and can be substituted with a sulfonic acid group, Z being an alkylene group having 1 to 40 carbon atoms which can be substituted with a halogen atom, p being an integer of 1 or more, R e is a hydrogen atom, an alkyl group having 1 to 40 carbon atoms, a fluoroalkyl group having 1 to 40 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

[0027] 4. The charge transportable ink composition according to 3, wherein the R 1 is a sulfonic acid group, the R 2 is an alkoxy group having 1 to 40 carbon atoms or -O-[Z-O] p -R e , or is -O-Y-O- formed by bonding of R 1 and R 2 .

[0028] 5. The charge transportable ink composition according to any one of 1 to 4, further comprising a dopant substance.

[0029] 6. The charge transportable ink composition according to 5, wherein the dopant substance contains at least one selected from an arylsulfonic acid compound and a heteropoly acid compound.

[0030] 7. The charge transportable ink composition according to any one of claims 1 to 6, further comprising metal oxide nanoparticles.

[0031] 8. A charge transportable thin film obtained from the charge transportable ink composition according to any one of claims 1 to 7.

[0032] 9. An electronic element having the charge transportable thin film according to claim 8.

[0033] 10. The electronic element according to claim 9, which is an organic electroluminescent element.

[0034] 11. A method for improving the storage stability of a charge transportable ink composition, which is a method for improving the storage stability of a charge transportable ink composition comprising an amine compound, a charge transportable substance, and an organic solvent, characterized by using, as the amine compound, an amine compound represented by the following formula (P1),

[0035] [Chem. 3]

[0036] R m -O-R n -NH2 (P1)

[0037] in the formula, R m represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, R n represents an alkylene group having 1 to 20 carbon atoms, an alkenylene group having 2 to 20 carbon atoms, or an arylene group having 6 to 20 carbon atoms, or R m and R n are mutually bonded, and represent an alkane triyl group having 3 to 40 carbon atoms, R n an alkylene group having 1 to 20 carbon atoms, and an alkenylene group having 2 to 20 carbon atoms of R m and R n an alkane triyl group in the case where the alkane triyl group of R

[0038] 12. A method for improving the planarity of a charge transportable thin film, which is a method for improving the planarity of a charge transportable thin film obtained from a charge transportable ink composition comprising an amine compound, a charge transportable substance, and an organic solvent, characterized by using, as the amine compound, an amine compound represented by the following formula (P1),

[0039] [Chem. 4]

[0040] R m -O-R n -NH2 (P1)

[0041] in the formula, R mR represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms. n Represents an alkylene group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, or R m With R n Mutually bonded, representing alkane triaryl groups with 3 to 40 carbon atoms, R n Alkylene groups with 1 to 20 carbon atoms and alkenylene groups with 2 to 20 carbon atoms, as well as R m and R n When the alkane trimethyl group is bonded to -NH2 in formula (P1), it is limited to forming -CH2-NH2 group.

[0042] The effects of the invention

[0043] By using the charge-transporting ink composition of the present invention, a charge-transporting film with excellent flatness can be obtained. Furthermore, the charge-transporting ink composition of the present invention exhibits excellent stability to atmospheric exposure. This charge-transporting film is suitable for use as a film in electronic components, primarily organic EL devices. Attached Figure Description

[0044] Figure 1 The absorption spectra are those of the charge-transporting ink compositions obtained in the examples and comparative examples. Detailed Implementation

[0045] The present invention will now be described in more detail.

[0046] The charge-transporting ink composition of the present invention comprises an amine compound represented by the following formula (P1), a charge-transporting substance, and an organic solvent. It should be noted that in the present invention, the term "solid component" in relation to the charge-transporting ink composition of the present invention refers to components other than the solvent contained in the composition. Furthermore, the term "charge-transporting" is synonymous with both conductivity and hole transport. The charge-transporting ink composition of the present invention can be a composition that inherently possesses charge-transporting properties, or a composition in which a solid film obtained using the composition possesses charge-transporting properties.

[0047] [Chemistry 5]

[0048] R m -OR n -NH2 (P1)

[0049] In the formula, R m R represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms. n Represents an alkylene group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, or Rm and R n bonded to each other, represent an alkane triyl group having 3 to 40 carbon atoms, R n alkylene group having 1 to 20 carbon atoms and an alkenylene group having 2 to 20 carbon atoms, and R m and R n The alkane triyl group of R

[0050] As the alkyl group having 1 to 20 carbon atoms, any of a linear, branched, or cyclic one can be mentioned, and as specific examples thereof, mention can be made of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n-eicosyl, and the like.

[0051] As the alkenyl group having 2 to 20 carbon atoms, mention can be made of ethenyl, n-1- propenyl, n-2-propenyl, 1-methylethenyl, n-1-butenyl, n-2-butenyl, n-3-butenyl, 2-methyl-1- propenyl, 2-methyl-2-propenyl, 1-ethylethenyl, 1-methyl-1-propenyl, 1-methyl-2-propenyl, n-1-pentenyl, n-1-decenyl, n-1-eicosenyl, and the like.

[0052] As the aryl group having 6 to 20 carbon atoms, mention can be made of phenyl, tolyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl, 9-phenanthryl, and the like, with phenyl, tolyl, and naphthyl being preferred.

[0053] As the alkylene group having 1 to 20 carbon atoms, a divalent group derived from removal of 2 hydrogen atoms from an alkane, any of a linear, branched, or cyclic one can be mentioned, and as specific examples thereof, mention can be made of methylene, ethylene, propylene, trimethylene, tetramethylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, tridecylene, tetradecylene, pentadecylene, hexadecylene, heptadecylene, octadecylene, nonadecylene, eicosylene, and the like.

[0054] As an alkenyl group with 2 to 20 carbon atoms, it is a divalent group derived from an olefin by removing two hydrogen atoms. Examples include vinylene, propenylene, butenylene, pentenylene, hexenylene, heptenylene, octene, nonenylene, decenylene, undecenylene, dodecenylene, tridecenylene, tetradecenylene, pentadecenylene, hexadecenylene, heptadecenylene, octadecenylene, nonadecenylene, and eicosene.

[0055] As arylene groups with 6 to 20 carbon atoms, examples of groups obtained by removing one hydrogen atom from specific examples of arylene groups with 6 to 12 carbon atoms mentioned above can be listed, such as phenylene, naphthylene, biphenylene, etc.

[0056] As alkane triaryl groups with 3 to 40 carbon atoms, these are trivalent groups derived from alkanes by removing hydrogen atoms. Examples include groups represented by the following formula (K1).

[0057] [Chemistry 6]

[0058]

[0059] (where n) r n represents an integer from 0 to 10. c Represents an integer from 1 to 10, with * indicating a bonded terminator.

[0060] As mentioned above, R m Preferably, it is an alkyl group with 1 to 20 carbon atoms, more preferably an alkyl group with 1 to 10 carbon atoms, even more preferably an alkyl group with 1 to 8 carbon atoms, and even more preferably an alkyl group with 1 to 5 carbon atoms.

[0061] As mentioned above, R n Preferably, the alkylene group has 1 to 20 carbon atoms, more preferably it has 1 to 10 carbon atoms, even more preferably it has 1 to 8 carbon atoms, and even more preferably it has 1 to 5 carbon atoms.

[0062] The above n r Preferably 1 to 3, more preferably 1 to 2, and even more preferably 1, wherein the above n c Preferably 1 to 3, more preferably 1 to 2, and even more preferably 1.

[0063] As mentioned above, n r With n c The combination of n is preferred. r and n c All are 1 to 3, with n being more preferred. r and n c Both are 1 to 2, further optimization of n r For 1 to 2, n c If the value is 1, then n can be further optimized.r and n c are each 1.

[0064] As specific examples of the amine compound represented by formula (P1), the following compounds can be exemplified, but are not limited thereto.

[0065] [Chemical Formula 7]

[0066]

[0067] In the charge transportable ink composition of the present application, the content of the amine compound represented by formula (P1) is not particularly limited, and is preferably 0.01 to 10 mass times, more preferably 0.01 to 8 mass times, further more preferably 0.01 to 6 mass times, and still further more preferably 0.01 to 4 mass times, with respect to the charge transportable substance 1, in terms of stability to atmospheric exposure, good reproducibility, and excellent planarity of the thin film.

[0068] As the charge transportable substance used in the present application, there is no particular limitation, and a charge transportable compound, a charge transportable oligomer, a charge transportable polymer, and the like used in the field of organic EL elements and the like can be appropriately selected and used.

[0069] As specific examples thereof, various charge transportable compounds such as an oligoaniline derivative, an N,N'-diarylbenzidine derivative, an N,N,N',N'-tetraarylbenzidine derivative, and the like arylamine derivative, an oligothiophene derivative, a thienothiophene derivative, a thienobenzothiophene derivative, and the like thiophene derivative, a pyrrole derivative such as an oligopyrrole, a charge transportable oligomer, a polythiophene derivative, a polyaniline derivative, a polypyrrone derivative, and the like charge transportable polymer, and the like, and a polythiophene derivative is particularly preferred.

[0070] In a preferable aspect, the charge transportable substance is a polythiophene derivative or an amine adduct thereof containing a repeating unit represented by formula (1).

[0071] [Chemical Formula 8]

[0072]

[0073] In the formula, R 1 and R 2 are each independently a hydrogen atom, an alkyl group having 1 to 40 carbon atoms, a fluoroalkyl group having 1 to 40 carbon atoms, an alkoxy group having 1 to 40 carbon atoms, a fluoroalkoxy group having 1 to 40 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, -O-[Z-O] p -R e or a sulfonic acid group, or R 1 and R 2—O—Y—O—, Y is an alkylene group having 1 to 40 carbon atoms which can contain an ether bond, can be substituted with a sulfonic acid group, Z is an alkylene group having 1 to 40 carbon atoms which can be substituted with a halogen atom, p is an integer of 1 or more, R e is a hydrogen atom, an alkyl group having 1 to 40 carbon atoms, a fluoroalkyl group having 1 to 40 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

[0074] As the alkyl group having 1 to 40 carbon atoms, any of a linear, branched, or cyclic one can be used, and as specific examples, in addition to the above-mentioned alkyl groups having 1 to 20 carbon atoms, dodecyl, tridecyl, and tetradecyl groups, etc. can be given. In the present application, an alkyl group having 1 to 18 carbon atoms is preferred, and an alkyl group having 1 to 8 carbon atoms is more preferred.

[0075] As the fluoroalkyl group having 1 to 40 carbon atoms, any of the alkyl groups having 1 to 40 carbon atoms in which at least one hydrogen atom on the carbon atom is substituted with a fluorine atom can be used, and as specific examples, fluoromethyl, difluoromethyl, perfluoromethyl, 1-fluoroethyl, 2-fluoroethyl, 1,2-difluoroethyl, 1,1-difluoroethyl, 2,2-difluoroethyl, 1,1,2-trifluoroethyl, 1,2,2-trifluoroethyl, 2,2,2-trifluoroethyl, 1,1,2,2-tetrafluoroethyl, 1,2,2,2-tetrafluoroethyl, perfluoroethyl, 1-fluoropropyl, 2-fluoropropyl, 3-fluoropropyl, 1,1-difluoropropyl, 1,2-difluoropropyl, 1,3-difluoropropyl, 2,2-difluoropropyl, 2,3-difluoropropyl, 3,3-difluoropropyl, 1,1,2-trifluoropropyl, 1,1,3-trifluoropropyl, 1,2,3-trifluoropropyl, 1,3,3-trifluoropropyl, 2,2,3-trifluoropropyl, 2,3,3-trifluoropropyl, 3,3,3-trifluoropropyl, 1,1,2,2-tetrafluoropropyl, 1,1,2,3-tetrafluoropropyl, 1,2,2,3-tetrafluoropropyl, 1,3,3,3-tetrafluoropropyl, 2,2,3,3-tetrafluoropropyl, 2,3,3,3-tetrafluoropropyl, 1,1,2,2,3-pentafluoropropyl, 1,2,2,3,3-pentafluoropropyl, 1,1,3,3,3-pentafluoropropyl, 1,2,3,3,3-pentafluoropropyl, 2,2,3,3,3-pentafluoropropyl, perfluoropropyl, perfluorobutyl, perfluoropentyl, perfluorohexyl, perfluoroheptyl, and perfluorooctyl groups, etc. can be given.

[0076] As the alkoxy group having 1 to 40 carbon atoms, any of a linear, branched, or cyclic alkyl group can be used, and specific examples include methoxy, ethoxy, n-propoxy, isopropoxy, cyclopropoxy, n-butoxy, isobutoxy, sec-butoxy, t-butoxy, n-pentoxy, n-hexyloxy, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, n-undecyloxy, n-dodecyloxy, n-tridecyloxy, n-tetradecyloxy, n-pentadecyloxy, n-hexadecyloxy, n-heptadecyloxy, n-octadecyloxy, n-nonadecyloxy, and n-icosyloxy.

[0077] As the fluoroalkoxy group having 1 to 40 carbon atoms, any of the alkoxy groups having 1 to 40 carbon atoms in which at least one hydrogen atom on the carbon atom is replaced with a fluorine atom can be used, and specific examples include fluoromethoxy, difluoromethoxy, perfluoromethoxy, 1-fluoroethoxy, 2-fluoroethoxy, 1,2-difluoroethoxy, 1,1-difluoroethoxy, 2,2-difluoroethoxy, 1,1,2-trifluoroethoxy, 1,2,2-trifluoroethoxy, 2,2,2-trifluoroethoxy, 1,1,2,2-tetrafluoroethoxy, 1,2,2,2-tetrafluoroethoxy, perfluoroethoxy, 1-fluoropropoxy, 2-fluoropropoxy, 3-fluoropropoxy, 1,1-difluoropropoxy, 1,2-difluoropropoxy, 1,3-difluoropropoxy, 2,2-difluoropropoxy, 2,3-difluoropropoxy, 3,3-difluoropropoxy, 1,1,2-trifluoropropoxy, 1,1,3-trifluoropropoxy, 1,2,3-trifluoropropoxy, 1,3,3-trifluoropropoxy, 2,2,3-trifluoropropoxy, 2,3,3-trifluoropropoxy, 3,3,3-trifluoropropoxy, 1,1,2,2-tetrafluoropropoxy, 1,1,2,3-tetrafluoropropoxy, 1,2,2,3-tetrafluoropropoxy, 1,3,3,3-tetrafluoropropoxy, 2,2,3,3-tetrafluoropropoxy, 2,3,3,3-tetrafluoropropoxy, 1,1,2,2,3-pentafluoropropoxy, 1,2,2,3,3-pentafluoropropoxy, 1,1,3,3,3-pentafluoropropoxy, 1,2,3,3,3-pentafluoropropoxy, 2,2,3,3,3-pentafluoropropoxy, and perfluoropropoxy.

[0078] As the alkylene group having 1 to 40 carbon atoms, any of a linear, branched, or cyclic alkylene group can be used, and specific examples include the same groups as the above-mentioned examples of the alkylene group.

[0079] As the aryl group having 6 to 20 carbon atoms, the same groups as the above-mentioned examples of the aryl group can be used. In the present application, a phenyl group, a tolyl group, and a naphthyl group are preferred.

[0080] As the aryloxy group having 6 to 20 carbon atoms, for example, a phenoxy group, an anthryloxy group, a naphthoxy group, a phenanthryloxy group, and a fluorenyloxy group can be used.

[0081] As the halogen atom, a fluorine atom, a chlorine atom, a bromine atom and an iodine atom can be mentioned.

[0082] In the above formula (1), R 1 and R 2 independently of one another are a hydrogen atom, a fluorine alkyl group having 1 to 40 carbon atoms, an alkoxy group having 1 to 40 carbon atoms, -O[C(R a R b )-C(R c R d )-O] p -R e , -OR f or a sulfonic acid group, or R 1 and R 2 are bonded to form -O-Y-O-.

[0083] R a to R d independently of one another represent a hydrogen atom, an alkyl group having 1 to 40 carbon atoms, a fluorine alkyl group having 1 to 40 carbon atoms or an aryl group having 6 to 20 carbon atoms, and as specific examples of these groups, the same groups as mentioned above can be mentioned.

[0084] wherein R a to R d independently of one another are a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a fluorine alkyl group having 1 to 8 carbon atoms or a phenyl group.

[0085] R e is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a fluorine alkyl group having 1 to 8 carbon atoms or a phenyl group, preferably a hydrogen atom, a methyl group, a propyl group or a butyl group.

[0086] Further, p is preferably 1 to 5, more preferably 1, 2 or 3.

[0087] R f is a hydrogen atom, an alkyl group having 1 to 40 carbon atoms, a fluorine alkyl group having 1 to 40 carbon atoms or an aryl group having 6 to 20 carbon atoms, preferably a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a fluorine alkyl group having 1 to 8 carbon atoms or a phenyl group, more preferably -CH2CF3.

[0088] In the present application, R 1 is preferably a hydrogen atom or a sulfonic acid group, more preferably a sulfonic acid group, and R 2 is preferably an alkoxy group having 1 to 40 carbon atoms or -O-[Z-O] p -R e , more preferably -O[C(R a R b )-C(R c R d )-O]p -R e or -OR f , further preferably -O[C(R a R b )-C(R c R d )-O] p -R e , -O-CH2CH2-O-CH2CH2-O-CH3, -O-CH2CH2-O-CH2CH2-OH or -O-CH2CH2-OH, or R 1 and R 2 bonded to each other to form -O-Y-O-.

[0089] For example, the above-mentioned polythiophene derivative according to the preferred embodiment of the present application contains a repeating unit of R 1 which is a sulfonic acid group, a repeating unit of R 2 which is a group other than a sulfonic acid group, or a repeating unit of R 1 and R 2 bonded to each other to form -O-Y-O-.

[0090] Preferably, the above-mentioned polythiophene derivative contains a repeating unit of R 1 which is a sulfonic acid group, a repeating unit of R 2 which is an alkoxy group having 1 to 40 carbon atoms or -O-[Z-O] p -R e , or a repeating unit of R 1 and R 2 bonded to each other to form -O-Y-O-.

[0091] More preferably, the above-mentioned polythiophene derivative contains a repeating unit of R 1 which is a sulfonic acid group, a repeating unit of R 2 which is -O[C(R a R b )-C(R c R d )-O] p -R e or -OR f .

[0092] Further preferably, the above-mentioned polythiophene derivative contains a repeating unit of R 1 which is a sulfonic acid group, a repeating unit of R 2 which is -O[C(R a R b )-C(R c R d )-O] p -R e , or a repeating unit of R 1 and R 2repeating units of -O-Y-O- formed by bonding.

[0093] More preferably, the above polythiophene derivative contains R 1 is a sulfonic acid group, R 2 repeating units of -O-CH2CH2-O-CH2CH2-O-CH3, -O-CH2CH2-O-CH2CH2-OH, or -O-CH2CH2-OH, or contains repeating units of R 1 and R 2 repeating units of groups represented by the following formulae (Yl) and (Y2) formed by bonding to each other.

[0094] [Chemical Formula 9]

[0095]

[0096] As a preferable specific example of the above polythiophene derivative, for example, a polythiophene containing at least one repeating unit represented by the following formulae (1-1) to (1-5) can be exemplified.

[0097] [Chemical Formula 10]

[0098]

[0099] Further, as a suitable structure of the above polythiophene derivative, for example, a polythiophene derivative having a structure represented by the following formula (la) can be exemplified. Note that in the following formulae, each unit can be bonded at random or as a block polymer.

[0100] [Chemical Formula 11]

[0101]

[0102] In the formula, a to d represent the molar ratio of each unit, and satisfy 0≤a≤l, 0≤b≤l, 0

[0103] Further, the above polythiophene derivative can be a homopolymer or a copolymer (statistically, including random, gradient, and block copolymers). As a polymer containing monomer A and monomer B, block copolymers include, for example, A-B diblock copolymers, A-B-A triblock copolymers, and (AB) m - multiblock copolymers. The polythiophene can contain repeating units derived from other types of monomers (e.g., thienothiophene, selenophene, pyrrole, furan, tellurophene, aniline, arylamine, and arylene (e.g., phenylene, phenylenevinylene, and fluorenylene, etc.), etc.).

[0104] In the present application, the content of the repeating unit represented by formula (1) in the polythiophene derivative is preferably more than 50 mol%, more preferably 80 mol% or more, further preferably 90 mol% or more, more further preferably 95 mol% or more, and most preferably 100 mol% of the total repeating units contained in the polythiophene derivative.

[0105] In the present application, depending on the purity of the initial monomer used for polymerization, the formed polymer can contain repeating units derived from impurities. In the present application, the term "homopolymer" as described above means a polymer containing repeating units derived from one kind of monomer, but can contain repeating units derived from impurities. In the present application, the above polythiophene derivative is preferably a polymer in which substantially all of the repeating units are the repeating unit represented by the above formula (1), and more preferably a polymer containing at least one of the repeating units represented by the above formulae (1-1) to (1-5).

[0106] In the present application, in the case where the above polythiophene derivative contains a repeating unit having a sulfonic acid group, from the viewpoint of further improving the solubility and dispersibility in organic solvents, it is preferable that at least a part of the sulfonic acid groups contained in the polythiophene derivative be added with an amine adduct of an amine compound.

[0107] As the amine compound which can be used in the formation of the amine adduct, there can be mentioned monalkylamine compounds such as methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, sec-butylamine, t-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, 2-ethylhexylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-nonadecylamine, n-icosylamine, primary amine compounds such as aniline, toluidine, 1-naphthylamine, 2-naphthylamine, 1-anthrylamine, 2-anthrylamine, 9-anthrylamine, 1-phenanthrylamine, 2-phenanthrylamine, 3-phenanthrylamine, 4-phenanthrylamine, 9-phenanthrylamine, dialkylamine compounds such as N-ethylmethylamine, N-methyln-propylamine, N-methylisopropylamine, N-methyln-butylamine, N-methylsec-butylamine, N-methyl-t-butylamine, N-methylisobutylamine, diethylamine, N-ethyln-propylamine, N-ethyisopropylamine, N-ethyln-butylamine, N-ethylsec-butylamine, N-ethyl-t-butylamine, di-n-propylamine, N-n-propylisopropylamine, N-n-propyln-butylamine, diisopropylamine, N-n-butyisopropylamine, N-t-butyisopropylamine, di-n-butylamine, di-sec-butylamine, diisobutylamine, aziridine (ethyleneimine), 2-methylaziridine (propyleneimine), 2,2-dimethylaziridine, azetidine (trimethyleneimine), 2-methylazetidine, pyrrolidine, 2-methylpyrrolidine, 3-methylpyrrolidine, 2,5-dimethylpyrrolidine, piperidine, 2,6-dimethylpiperidine, 3,5-dimethylpiperidine, 2,2,6,6-tetramethylpiperidine, hexamethyleneimine, heptamethyleneimine, octamethyleneimine, diarylamine compounds such as diphenylamine, N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine, 1,1'-binaphthylamine, 2,2'-binaphthylamine, 1,2'-binaphthylamine, carbazole, 7H-benzo[c]carbazole, 11H-benzo[a]carbazole, 7H-dibenzo[c,g]carbazole, 13H-dibenzo[a,i]carbazole, alkylarylamine compounds such as N-methylaniline, N-ethylaniline, N-n-propylaniline, N-isopropylaniline, N-n-butyIaniline, N-sec-butyIaniline, N-isobutyIaniline, N-methyl-1-naphthylamine, N-ethyl-1-naphthylamine, N-n-propyl-1-naphthylamine, indoline, isoindoline, 1,2,3,4-tetrahydroquinoline, 1,2,3,4-tetrahydroisoquinoline, and secondary amine compounds.N,N-Dimethylethylamine, N,N-Dimethyl-n-propylamine, N,N-Dimethylisopropylamine, N,N-Dimethyl-n-butylamine, N,N-Dimethyl-sec-butylamine, N,N-Dimethyl-tert-butylamine, N,N-Dimethylisobutylamine, N,N-Diethylmethylamine, N-methyl-n-propylamine, N-methyl-n-butylamine, N-methyl-n-butylamine, triethylamine, N,N-Diethyl-n-butylamine, N,N-Diisopropylethylamine, N,N-Di-n-butylethylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, triisobutylamine, 1-methylazacyclobutane, 1- Trialkylamine compounds such as methylpyrrolidine and 1-methylpiperidine; triarylamine compounds such as triphenylamine; alkyldiarylamine compounds such as N-methyldiphenylamine, N-ethyldiphenylamine, 9-methylcarbazole, and 9-ethylcarbazole; and dialkylarylamine compounds such as N,N-diethylaniline, N,N-di-n-propylaniline, N,N-diisopropylaniline, and N,N-di-n-butylaniline, etc., are preferred tertiary amine compounds, taking into account the balance between the solubility of the amine adduct and the charge transport properties of the resulting charge transport film. Trialkylamine compounds are more preferred, and triethylamine is even more preferred.

[0108] As for amine adducts, they can be obtained by adding polythiophene derivatives to the amine itself or its solution and stirring thoroughly.

[0109] In this invention, the above-mentioned polythiophene derivatives or their amine adducts may be products treated with a reducing agent.

[0110] In polythiophene derivatives or their amine adducts, the chemical structure of a portion of the repeating unit constituting them sometimes becomes an oxidized structure known as a "quinone structure." The term "quinone structure" is used in contrast to the term "benzene ring structure," which, as a structure containing an aromatic ring, refers to a structure in which the double bonds within the aromatic ring move outward (resulting in the disappearance of the aromatic ring) and form two exocyclic double bonds conjugated with the other double bonds remaining within the ring. The relationship between these two structures can be readily understood by those skilled in the art from the relationship between the structures of benzoquinone and hydroquinone. The quinone structure of the repeating unit of various conjugated polymers is well known to those skilled in the art. As an example, the quinone structure corresponding to the repeating unit of a polythiophene derivative containing the repeating unit represented by the above formula (1) is shown in the following formula (1').

[0111] [Chemistry 12]

[0112]

[0113] (where R is in the formula) 1 and R 2 As defined in equation (1) above.

[0114] The quinoid structure is generated in a process of oxidation reaction by a dopant, so-called doping reaction, in a polythiophene derivative containing a repeating unit represented by the above formula (1), and a part of a structure called "polaron structure" and "dipolaron structure" that imparts charge transportability is generated in the polythiophene derivative. These structures are known. In the production of an organic EL element, it is necessary to introduce "polaron structure" and / or "dipolaron structure", and in fact, when a film formed from a charge transportable ink composition is subjected to a firing treatment in the production of an organic EL element, the above-mentioned doping reaction is intentionally caused to achieve this. It is considered that the reason why the quinoid structure is contained in the polythiophene derivative before the doping reaction is caused is that the polythiophene derivative has undergone an unintended oxidation reaction equivalent to the doping reaction in the production process thereof, particularly in a sulfonation step therein.

[0115] The amount of the quinoid structure contained in the above polythiophene derivative has a correlation with the solubility and dispersibility of the polythiophene derivative in an organic solvent, and if the amount of the quinoid structure increases, the solubility and dispersibility tend to decrease. Therefore, the introduction of the quinoid structure after a film is formed from a charge transportable ink composition does not cause a problem, but if the quinoid structure is excessively introduced in the polythiophene derivative by the above unintended oxidation reaction, it sometimes causes an obstacle to the production of the charge transportable ink composition. It is known that there is a variation in the solubility and dispersibility in an organic solvent in polythiophene derivatives, and it is considered that one of the reasons is that the amount of the quinoid structure introduced in the polythiophene by the above unintended oxidation reaction varies depending on the difference in the production conditions of the respective polythiophene derivatives.

[0116] Therefore, if the above polythiophene derivative is subjected to a reduction treatment using a reducing agent, even if the quinoid structure is excessively introduced in the polythiophene derivative, the quinoid structure is reduced by reduction, the solubility and dispersibility of the polythiophene derivative in an organic solvent are improved, and thus a good charge transportable ink composition that forms a film excellent in uniformity can be stably produced.

[0117] As to the conditions of the reduction treatment, there is no particular limitation as long as the above quinoid structure can be reduced and appropriately converted into a non-oxidized structure, that is, the above benzene ring structure (for example, in a polythiophene derivative containing a repeating unit represented by the above formula (1), the quinoid structure represented by the above formula (1') is converted into a structure represented by the above formula (1)), and for example, the treatment can be performed by merely bringing the polythiophene derivative, amine adduct, and reducing agent into contact with or without an appropriate solvent.

[0118] As to such a reducing agent, there is no particular limitation as long as reduction is appropriately performed, and for example, ammonia water, hydrazine, and the like that are easily available as commercial products are appropriate.

[0119] Further, the amount of the reducing agent varies depending on the amount of the reducing agent used, and thus cannot be generally defined, but in relation to 100 parts by mass of the polythiophene derivative, amine adduct to be treated, it is usually 0.1 parts by mass or more from the viewpoint of appropriately performing reduction, and 10 parts by mass or less from the viewpoint of not leaving an excess of the reducing agent.

[0120] As an example of a specific method of the reduction treatment, the polythiophene derivative, amine adduct is stirred in 28% ammonia water at room temperature overnight. By this reduction treatment under a comparatively mild condition, the solubility and dispersibility of the polythiophene derivative, amine adduct in an organic solvent are sufficiently improved.

[0121] In the charge transportable ink composition of the present application, in the case of using the amine adduct of the polythiophene derivative, the above reduction treatment can be performed before the formation of the amine adduct, or can be performed after the formation of the amine adduct.

[0122] It should be noted that by the reduction treatment, the solubility and dispersibility of the polythiophene derivative or the amine adduct thereof in a solvent change, and as a result, the polythiophene derivative or the amine adduct thereof which was not dissolved in the reaction system at the start of the treatment is sometimes dissolved at the end of the treatment. In such a case, an organic solvent which is not compatible with the polythiophene derivative or the amine adduct thereof (in the case of a sulfonated polythiophene, acetone, isopropyl alcohol, etc.) is added to the reaction system, a precipitate of the polythiophene derivative or the amine adduct thereof is formed, and by performing a method such as filtration, the polythiophene derivative or the amine adduct thereof can be recovered.

[0123] The weight average molecular weight of the polythiophene derivative or the amine adduct thereof containing the repeating unit represented by formula (1) is preferably about 1000 to 1000000, more preferably about 5000 to 100000, and further preferably about 10000 to about 50000. By making the weight average molecular weight be the lower limit or more, a good conductivity is obtained with good reproducibility, and by making it be the upper limit or less, the solubility in a solvent is improved. It should be noted that the weight average molecular weight is a polystyrene-equivalent value using gel permeation chromatography.

[0124] The polythiophene derivative or the amine adduct thereof contained in the charge transportable ink composition of the present application can be a single one of the polythiophene derivative or the amine adduct thereof containing the repeating unit represented by formula (1), or two or more.

[0125] Furthermore, the polythiophene derivative containing the repeating unit represented by formula (1) can be a commercially available product, or a product polymerized using a known method with thiophene derivatives as starting materials. In either case, a product refined by methods such as reprecipitation or ion exchange is preferred. By using refined polythiophene derivatives, the characteristics of organic EL elements having films obtained from the charge-transporting ink composition of the present invention can be further improved.

[0126] It should be noted that sulfonation of conjugated polymers and sulfonated conjugated polymers (including sulfonated polythiophene) are described in U.S. Patent No. 8,017,241 to Seshadri et al. Additionally, sulfonated polythiophene is described in International Publications Nos. 2008 / 073149 and 2016 / 171935.

[0127] In this invention, at least a portion of the polythiophene derivative or its amine adduct containing repeating units represented by formula (1) contained in the charge-transfer ink composition is dissolved in an organic solvent.

[0128] In this invention, as a charge transporting material, a charge transporting material consisting of a polythiophene derivative or its amine adduct containing a repeating unit represented by formula (1) and other charge transporting compounds may be used together, preferably containing only a polythiophene derivative or its amine adduct containing a repeating unit represented by formula (1).

[0129] Regarding the content of charge-transporting substance in the charge-transporting ink composition of the present invention, it is generally appropriately determined within the range of 0.05 to 40% by mass, preferably 0.1 to 35% by mass, of the solid component, taking into account the required film thickness, viscosity of the ink composition, etc.

[0130] The charge transportable ink composition of the present application contains an organic solvent. As such an organic solvent, there is no particular limitation as long as the solid component is dispersed or dissolved. As specific examples thereof, for example, an aromatic or halogenated aromatic hydrocarbon solvent such as benzene, toluene, xylene, ethylbenzene, chlorobenzene, and the like; an aliphatic hydrocarbon such as n-heptane, n-hexane, cyclohexane, and the like; an ether-based solvent such as diethyl ether, tetrahydrofuran, dioxane, 1,2-dimethoxyethane, and the like; a ketone-based solvent such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and the like; an ester-based solvent such as ethyl acetate, n-hexyl acetate, ethyl lactate, γ-butyrolactone, propylene carbonate, diisopropyl malonate, and the like; a halogenated hydrocarbon solvent such as dichloromethane, dichloroethane, 1,2-dichloroethane, chloroform, and the like; an amide-based solvent such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, and the like; an alcohol-based solvent such as methanol, ethanol, isopropanol, n-propanol, cyclohexanol, diacetone alcohol, 2-benzoyl ethanol, and the like; a glycol ether-based solvent such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol diglycidyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, triethylene glycol monobutyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and the like; a glycol-based solvent such as ethylene glycol, propylene glycol, hexylene glycol, 1,3-octylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, and the like; and the like can be appropriately selected from among these.

[0131] Among these, in the present application, an amide-based solvent, a glycol ether-based solvent, and a glycol-based solvent are preferred, and 1,3-dimethyl-2-imidazolidinone, dipropylene glycol, and dipropylene glycol monomethyl ether are more preferred.

[0132] Note that these organic solvents can each be used alone or two or more of them can be used in combination.

[0133] In the charge transportable ink composition of the present application, water can also be contained as a solvent, and in terms of the content of water, it is preferred that the content of water be 10% by mass or less, more preferably 5% by mass or less, of the entire solvent, and it is most suitable to use only an organic solvent as a solvent. Note that "only an organic solvent" in this case means that only an organic solvent is used as a solvent, and the presence of "water" in a trace amount in the used organic solvent, the solid component, and the like is not denied.

[0134] The charge transportable ink composition of the present application can contain a metal oxide nanoparticle. By the term "nanoparticle", it means a fine particle of which the average particle diameter of primary particles is on the order of nanometers (typically 500 nm or less). The metal oxide nanoparticle means a metal oxide shaped into a nanoparticle.

[0135] The primary particle diameter of the metal oxide nanoparticle used in the present application is not particularly limited as long as it is on the order of nanometers, and if a film excellent in planarity is to be obtained with good reproducibility, it is preferably from 2 to 150 nm, more preferably from 3 to 100 nm, and further preferably from 5 to 50 nm. Note that the particle diameter is a measured value using a nitrogen adsorption isotherm by the BET method.

[0136] The metal constituting the metal oxide nanoparticle used in the present application includes, in addition to a metal in the usual sense, a semimetal.

[0137] As the metal in the usual sense, there is no particular limitation, and it is preferable to use one or two or more selected from the group consisting of tin (Sn), titanium (Ti), aluminum (Al), zirconium (Zr), zinc (Zn), niobium (Nb), tantalum (Ta), and tungsten (W).

[0138] On the other hand, by the term "semimetal", it means an element whose chemical and / or physical properties are intermediate between those of metals and nonmetals. A general definition of semimetals has not yet been established, and in the present application, six elements of boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), and tellurium (Te) are collectively taken as semimetals. These semimetals can be used alone, or two or more can be used in combination, and in addition, can be used in combination with a metal in the usual sense.

[0139] The metal oxide nanoparticle used in the present application preferably contains an oxide of one or two or more metals selected from the group consisting of boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), tin (Sn), titanium (Ti), aluminum (Al), zirconium (Zr), zinc (Zn), niobium (Nb), tantalum (Ta), and tungsten (W). Note that in the case where the metal is two or more in combination, the metal oxide can be a mixture of oxides of the respective individual metals, or can be a composite oxide containing a plurality of metals.

[0140] As specific examples of the metal oxide, there can be mentioned B2O3, B2O, SiO2, SiO, GeO2, GeO, As2O4, As2O3, As2O5, Sb2O3, Sb2O5, TeO2, SnO2, ZrO2, Al2O3, ZnO, and the like, with preference given to B2O3, B2O, SiO2, SiO, GeO2, GeO, As2O4, As2O3, As2O5, SnO2, SnO, Sb2O3, TeO2, and mixtures thereof, and with further preference given to SiO2.

[0141] The metal oxide nanoparticles contained in the charge transportable ink composition of the present application can be one alone or two or more.

[0142] The metal oxide nanoparticles contained in the charge transportable ink composition of the present application are preferably uniformly dispersed in the composition.

[0143] Note that the above metal oxide nanoparticles can contain one or more organic capping groups. The organic capping group can be reactive or non-reactive. As examples of the reactive organic capping group, there can be mentioned an organic capping group capable of cross-linking with the use of ultraviolet rays or a radical initiator.

[0144] In the charge transportable ink composition of the present application, the content of the metal oxide nanoparticles is not particularly limited, and from the viewpoint of inhibiting the aggregation of the particles in the charge transportable ink composition, the viewpoint of obtaining a thin film excellent in flatness with good reproducibility, and the like, it is preferable that the charge transportable ink composition contain 40 to 95 mass% of the solid content, more preferably 50 to 95 mass%, and most preferably 60 to 90 mass%.

[0145] In particular, in the present application, by using a metal oxide nanoparticle sol prepared by dispersing metal oxide nanoparticles, a composition in which the metal oxide nanoparticles are uniformly dispersed can be produced with good reproducibility.

[0146] That is, compared with the case where the metal oxide nanoparticles themselves are mixed and dispersed in a solvent together with a charge transportable substance or the like, by preparing a metal oxide nanoparticle sol in advance, mixing the sol with a mixture prepared by dissolving or dispersing a charge transportable substance or the like in a solvent, and the like, a charge transportable ink composition in which the metal oxide nanoparticles are uniformly dispersed can be produced with good reproducibility.

[0147] Such a metal oxide nanoparticle sol can be used as a commercially available product, and can also be prepared using a solvent and metal oxide nanoparticles that can be contained in the charge transportable ink composition of the present application, and a publicly known method.

[0148] In particular, in the production of the charge transportable ink composition of the present application, it is suitable to use a silica sol prepared by dispersing SiO2nanoparticles in a dispersion medium.

[0149] The silica sol is not particularly limited, and can be appropriately selected from publicly known silica sols.

[0150] The commercially available silica sol is generally in the form of a dispersion liquid. As the commercially available silica sol, there can be mentioned silica sols in which Si02nanoparticles are dispersed in various solvents such as water, methanol, methyl ethyl ketone, methyl isobutyl ketone, N,N-dimethylacetamide, ethylene glycol, isopropyl alcohol, methanol, ethylene glycol monopropyl ether, cyclohexanone, ethyl acetate, toluene, propylene glycol monomethyl ether acetate, and the like.

[0151] In particular, in the present application, the silica sol in which the dispersion medium is an alcohol-based solvent, a glycol-based solvent, or water is preferred, and the silica sol in which the dispersion medium is an alcohol-based solvent or a glycol-based solvent is more preferred. As the alcohol-based solvent or the glycol-based solvent, an alcohol or a glycol-based solvent that is water-soluble is preferred, and methanol, 2-propanol, ethylene glycol are more preferred.

[0152] As specific examples of the commercially available silica sol, there can be mentioned water-dispersible silica sols such as SNOWTEX (registered trademark) ST-O, ST-OS, ST-O-40, ST-OL, manufactured by Nissan Chemical Corporation; SILICADOL 20, 30, 40, manufactured by Japan Chemical Corporation; and the like, methanol silica sols such as MA-ST-M, MA-ST-L, IPA-ST, IPA-ST-L, IPA-ST-ZL, EG-ST, manufactured by Nissan Chemical Corporation; and the like, and organic silica sols, but are not limited to these.

[0153] The Si02nanoparticle concentration in the silica sol is generally about 5 to 50 mass%, and in the case where the Si02nanoparticle concentration is high, when the silica sol is mixed with a mixture in which a charge transport substance or the like is dissolved or dispersed in a solvent, the Si02nanoparticles sometimes coagulate depending on the kind of the solvent contained in the mixture, and therefore attention is required at the time of preparing the composition.

[0154] The charge transport ink composition of the present application contains an amine compound represented by formula (P1), a charge transport substance, and an organic solvent, and a dopant substance can be contained as necessary in order to improve the charge transport ability or the like. As the dopant substance, there is no particular limitation as long as it is dispersed or dissolved in at least one of the solvents used in the charge transport ink composition, and both inorganic and organic dopant substances can be used.

[0155] In the case where the charge transport ink composition of the present application contains a dopant substance, the content thereof is appropriately set in consideration of the kind, amount, and the like of the charge transport substance, and is generally in the range of 0.1 to 20.0 relative to 1 of the charge transport substance in terms of mass ratio.

[0156] As the inorganic doped substance, there are inorganic acids such as hydrogen chloride, sulfuric acid, nitric acid, phosphoric acid; metal halides such as aluminum chloride (III) (AlCl3), titanium chloride (IV) (TiCl4), boron tribromide (BBr3), boron trifluoride etherate (BF3-OEt2), iron chloride (III) (FeCl3), copper chloride (II) (CuCl2), antimony chloride (V) (SbCl5), antimony fluoride (V) (SbF5), arsenic fluoride (V) (AsF5), phosphorus fluoride (PF5), aluminum tris(4-bromophenyl) hexachloroantimonate (TBPAH); halogens such as Cl2, Br2, I2, ICl, ICl3, IBr, IF4; heteropoly acids such as phosphomolybdic acid, tungstic acid; and the like.

[0157] Further, as the organic doped substance, there are 7,7,8,8-tetracyanoquinodimethane (TCNQ), 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane, and the like; halogenated tetracyanoquinodimethane (halogenated TCNQ) such as 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, 2,5-dichloro-7,7,8,8-tetracyanoquinodimethane; benzoquinone derivatives such as tetrachloro-1,4-benzoquinone (chloranil), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ); arylsulfonic acid compounds such as benzene sulfonic acid, toluene sulfonic acid, p-styrene sulfonic acid, 2-naphthalene sulfonic acid, 4-hydroxybenzene sulfonic acid, 5-sulfosalicylic acid, p-dodecylbenzene sulfonic acid, dihexylbenzene sulfonic acid, 2,5-dihexylbenzene sulfonic acid, dibutyl naphthalene sulfonic acid, 6,7-dibutyl-2-naphthalene sulfonic acid, dodecyl naphthalene sulfonic acid, 3-dodecyl-2-naphthalene sulfonic acid, hexyl naphthalene sulfonic acid, 4-hexyl-1-naphthalene sulfonic acid, octyl naphthalene sulfonic acid, 2-octyl-1-naphthalene sulfonic acid, hexyl naphthalene sulfonic acid, 7-hexyl-1-naphthalene sulfonic acid, 6-hexyl-2-naphthalene sulfonic acid, dinonyl naphthalene sulfonic acid, 2,7-dinonyl-4-naphthalene sulfonic acid, dinonyl naphthalene disulfonic acid, 2,7-dinonyl-4,5-naphthalene disulfonic acid, 1,4-benzodioxane disulfonic acid derivatives described in International Publication No. 2005 / 000832, aryl sulfonic acid derivatives described in International Publication No. 2006 / 025342, dinonyl naphthalene sulfonic acid derivatives described in Japanese Patent Application Laid-Open No. 2005-108828, and the like; aromatic sulfonic acid compounds such as polystyrene sulfonic acid; non-aromatic sulfonic acid compounds such as 10-camphor sulfonic acid; and the like.

[0158] These inorganic and organic doped substances can be used singly or in combination of two or more.

[0159] In the present application, among these dopant substances, arylsulfonic acid compounds are suitable, as examples of the preferred arylsulfonic acid compounds, arylsulfonic acid compounds represented by formula (H1) or (H2) can be listed.

[0160] [Chemical Formula 13]

[0161]

[0162] A 1 represents O or S, preferably O.

[0163] A 2 represents a naphthalene ring or an anthracene ring, preferably a naphthalene ring.

[0164] A 3 represents a perfluorobiphenyl group having a valence of 2 to 4, and s represents 1 the number of bonds to A 3 , is an integer satisfying 2 ≤ s ≤ 4, preferably s is 2. 3 A 2 is a perfluorobiphenyldiyl group, preferably a perfluorobiphenyl-4,4'-diyl group, and s is 2.

[0165] q represents the number of sulfonic acid groups bonded to A 2 , is an integer satisfying 1 ≤ q ≤ 4, and 2 is most suitable.

[0166] A 4 ~A 8 independently represent a hydrogen atom, a halogen atom, a cyano group, an alkyl group having a carbon atom number of 1 to 20, a halogenated alkyl group having a carbon atom number of 1 to 20, or a halogenated alkenyl group having a carbon atom number of 2 to 20, at least three of A 4 ~A 8 are halogen atoms.

[0167] As the halogenated alkyl group having a carbon atom number of 1 to 20, trifluoromethyl group, 2,2,2-trifluoroethyl group, 1,1,2,2,2-pentafluoroethyl group, 3,3,3-trifluoropropyl group, 2,2,3,3,3-pentafluoropropyl group, 1,1,2,2,3,3,3-heptafluoropropyl group, 4,4,4-trifluorobutyl group, 3,3,4,4,4-pentafluorobutyl group, 2,2,3,3,4,4,4-heptafluorobutyl group, 1,1,2,2,3,3,4,4,4-nonafluorobutyl group, and the like can be listed.

[0168] As the halogenated alkenyl group having a carbon atom number of 2 to 20, perfluorovinyl group, perfluoropropenyl (allyl) group, perfluorobutenyl group, and the like can be listed.

[0169] Further, as examples of the halogen atom and the alkyl group having a carbon atom number of 1 to 20, the same groups as described above can be listed, and as the halogen atom, a fluorine atom is preferred.

[0170] Among these, A 4~A 8 Preferably, at least 3 of the groups represented by ~A are hydrogen atoms, halogen atoms, cyano groups, alkyl groups having 1 to 10 carbon atoms, haloalkyl groups having 1 to 10 carbon atoms, or haloalkenyl groups having 2 to 10 carbon atoms, and A 4 ~A 8 Preferably, at least 3 of the groups represented by ~A are hydrogen atoms, halogen atoms, cyano groups, alkyl groups having 1 to 5 carbon atoms, haloalkyl groups having 1 to 5 carbon atoms, or haloalkenyl groups having 2 to 5 carbon atoms, and A 4 ~A 8 Preferably, at least 3 of the groups represented by ~A are hydrogen atoms, halogen atoms, cyano groups, perfluoroalkyl groups having 1 to 5 carbon atoms, or perfluoroalkenyl groups having 1 to 5 carbon atoms, and A 4 , A 5 , and A 8 are fluorine atoms.

[0171] It should be noted that the perfluoroalkyl group is a group in which all the hydrogen atoms of an alkyl group are replaced with fluorine atoms, and the perfluoroalkenyl group is a group in which all the hydrogen atoms of an alkenyl group are replaced with fluorine atoms.

[0172] r represents the number of sulfonic acid groups bonded to the naphthalene ring and is an integer satisfying 1 < r < 4, preferably 2 to 4, and 2 is most suitable.

[0173] In the case where an organic compound is used as the dopant material, in terms of the molecular weight, it is preferably 3000 or less, and more preferably 2500 or less, if the solubility in an organic solvent is taken into consideration.

[0174] In particular, the molecular weight of the arylsulfonic acid compound used as the dopant material is not particularly limited, and it is preferably 2000 or less, and more preferably 1500 or less, if the solubility in an organic solvent is taken into consideration.

[0175] Examples of the arylsulfonic acid compound that can be suitably used in the present application include the following compounds, but are not limited to these.

[0176] [Chemical Formula 14]

[0177]

[0178] In the charge-transporting ink composition of the present application, an amine compound represented by formula (P1) and other amine compounds can be contained for the purpose of improving the dispersibility, solubility, or the like of the charge-transporting substance such as a polythiophene derivative or an amine adduct thereof.

[0179] Such other amine compounds are not particularly limited as long as they are soluble in at least one of the solvents used in the ink composition, and can be one kind alone or two or more kinds.

[0180] As specific examples of the primary amine compounds, there can be mentioned monoalkylamine compounds such as methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, sec-butylamine, t-butylamine, n-pentylamine, n-hexylamine, n-heptylamine, n-octylamine, 2-ethylhexylamine, n-nonylamine, n-decylamine, n-undecylamine, n-dodecylamine, n-tridecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-heptadecylamine, n-octadecylamine, n-nonadecylamine, n-icosylamine, etc.; monoarylamine compounds such as aniline, toluidine, 1-naphthylamine, 2-naphthylamine, 1-anthrylamine, 2-anthrylamine, 9-anthrylamine, 1-phenanthrylamine, 2-phenanthrylamine, 3-phenanthrylamine, 4-phenanthrylamine, 9-phenanthrylamine, etc.

[0181] As specific examples of the secondary amine compounds, there can be mentioned dialkylamine compounds such as N-ethylmethylamine, N-methyl-n-propylamine, N-methyl- isopropylamine, N-methyl-n-butylamine, N-methyl-sec-butylamine, N-methyl-t-butylamine, N-methyl-isobutylamine, diethylamine, N-ethyl-n-propylamine, N-ethyl- isopropylamine, N-ethyl-n-butylamine, N-ethyl-sec-butylamine, N-ethyl-t-butylamine, dipropylamine, N-n-propyl-isopropylamine, N-n-propyl-n-butylamine, N-n-propyl-sec-butylamine, diisopropylamine, N-n-butyl-isopropylamine, N-t-butyl-isopropylamine, di-n-butylamine, di-sec-butylamine, diisobutylamine, aziridine (ethyleneimine), 2-methylaziridine (propyleneimine), 2,2-dimethylaziridine, azetidine (trimethyleneimine), 2-methylazetidine, pyrrolidine, 2-methylpyrrolidine, 3-methylpyrrolidine, 2,5-dimethylpyrrolidine, piperidine, 2,6-dimethylpiperidine, 3,5-dimethylpiperidine, 2,2,6,6-tetramethylpiperidine, hexamethyleneimine, heptamethyleneimine, octamethyleneimine, etc.; diarylamine compounds such as diphenylamine, N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine, 1,1'-binaphthylamine, 2,2'-binaphthylamine, 1,2'-binaphthylamine, carbazole, 7H-benzo[c]carbazole, 11H-benzo[a]carbazole, 7H-dibenzo[c,g]carbazole, 13H-dibenzo[a,i]carbazole, etc.; alkylarylamine compounds such as N-methylaniline, N-ethylaniline, N-n-propylaniline, N-isopropylaniline, N-n-butylaniline, N-sec-butylaniline, N-isobutylaniline, N-methyl-1-naphthylamine, N-ethyl-1-naphthylamine, N-n-propyl-1-naphthylamine, indoline, isoindoline, 1,2,3,4-tetrahydroquinoline, 1,2,3,4-tetrahydroisoquinoline, etc.

[0182] As specific examples of the tertiary amine compounds, there can be mentioned trialkylamine compounds such as N,N-dimethylethylamine, N,N-dimethyl-n-propylamine, N,N-dimethylisopropylamine, N,N-dimethyl-n-butylamine, N,N-dimethyl-sec-butylamine, N,N-dimethyl-tert-butylamine, N,N-dimethylisobutylamine, N,N-diethylmethylamine, N-methyldi-n-propylamine, N-methyldiisopropylamine, N-methyldi-n-butylamine, N-methyldiisobutylamine, triethylamine, N,N-diethyl-n-butylamine, N,N-diisopropylethylamine, N,N-di-n-butylethylamine, tri-n-propylamine, triisopropylamine, tri-n-butylamine, triisobutylamine, 1-methylazetidine, 1-methylpyrrolidine, 1-methylpiperidine, and the like; triarylamine compounds such as triphenylamine; alkyl diarylamine compounds such as N-methyldiphenylamine, N-ethyldiphenylamine, 9-methylcarbazole, 9-ethylcarbazole, and the like; dialkylarylamine compounds such as N,N-diethylphenylamine, N,N-di-n-propylphenylamine, N,N-diisopropylphenylamine, N,N-di-n-butylphenylamine, and the like; and the like.

[0183] In particular, in the case where the charge transportable ink composition of the present application contains other amine compounds, the other amine compounds preferably contain primary amine compounds, and preferably contain monoalkylamines, particularly monoalkylamines having 2 or more and 20 or less carbon atoms, from the viewpoint of the ability to improve the dispersibility and solubility of the charge transportable substance such as the polythiophene derivative or the amine adduct thereof used in the present application.

[0184] In the case where the charge transportable ink composition of the present application contains other amine compounds, the content thereof is usually 10 times or less by mass, relative to the charge transportable substance such as the polythiophene derivative or the amine adduct thereof used in the present application.

[0185] In addition, heteropoly acids can also be suitably used as the dopant substance. The so-called heteropoly acid is a structure in which a heteroatom is located at the center of a molecule, represented by a Keggin type represented by Formula (A) or a Dawson type represented by Formula (B), and is a polyacid obtained by condensation of a homoacid such as vanadium (V), molybdenum (Mo), tungsten (W), or the like with an oxygen-containing acid of a different element. As the oxygen-containing acid of the different element, there can be mainly mentioned oxygen-containing acids of silicon (Si), phosphorus (P), arsenic (As).

[0186] [Chemical Formula 15]

[0187]

[0188] As specific examples of the heteropoly acids, there can be mentioned phosphomolybdic acid, silicomolybdic acid, phosphotungstic acid, silicotungstic acid, phosphotungstomolybdic acid, and the like, which can be used alone or in combination of two or more. Note that the heteropoly acid used in the present application can be obtained as a commercial product, and can also be synthesized by a publicly known method.

[0189] In particular, in the case where only one heteropoly acid is contained, the one heteropoly acid preferably contains tungsten. That is, phosphotungstic acid, silicotungstic acid, phosphotungstic molybdic acid, and the like are preferred, and phosphotungstic acid and silicotungstic acid are more preferred.

[0190] Note that, in the case of the heteropoly acid, even if the number ratio of elements is more or less than the structure represented by the general formula, as long as it is a product obtained as a commercial product or a product appropriately synthesized according to a publicly known synthesis method, it can be used in the present application.

[0191] That is, for example, generally, phosphotungstic acid is represented by the chemical formula H3(PW 12 O 40 ) • nH2O, but in quantitative analysis, even if the number of P (phosphorus), O (oxygen), or W (tungsten) in the formula is more or less, as long as it is a product obtained as a commercial product or a product appropriately synthesized according to a publicly known synthesis method, it can be used in the present application. In this case, the mass of the heteropoly acid specified in the present application is not the mass of pure phosphotungstic acid (phosphotungstic acid content) in a synthetic product or a commercial product, but means the total mass in a state where water of hydration, other impurities, and the like are contained in a form that can be obtained as a commercial product and a form that can be separated using a publicly known synthesis method.

[0192] The charge transportable ink composition of the present application can contain a publicly known organosilane compound. By containing such an organosilane compound in the charge transportable ink composition, in the case where a charge transportable film obtained from the ink composition is used as a hole injection layer of an organic EL element, it is possible to improve the hole injection property to a hole transport layer provided in contact therewith.

[0193] As the organosilane compound, an alkoxysilane is preferred, and a trialkoxysilane and a tetraalkoxysilane are more preferred. As the above alkoxysilane, tetraethoxysilane, tetramethoxysilane, tetraisopropoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, and the like can be exemplified. Of these, in the present application, tetraethoxysilane (TEOS), tetramethoxysilane, and tetraisopropoxysilane can be suitably used. These organosilane compounds can be used alone or two or more in combination.

[0194] When the charge-transfer ink composition of the present invention contains an organosilane compound, its content in the solid component is generally about 0.1 to 50% by mass. If a balance is taken into account to improve the flatness of the obtained film and suppress the reduction of charge transferability, it is preferably about 0.5 to 40% by mass, more preferably about 0.8 to 30% by mass, and even more preferably about 1 to 20% by mass.

[0195] The viscosity of the charge-transporting ink composition of the present invention is typically 1–50 mPa·s at 25°C, and the surface tension is typically 20–50 mN / m at 25°C. The viscosity and surface tension of the charge-transporting ink composition of the present invention can be adjusted by considering various factors such as the coating method used, the required film thickness, and by changing the type of organic solvent used, their ratio, and the concentration of solid components.

[0196] Furthermore, regarding the concentration of solid components in the charge-transporting ink composition of the present invention, it is appropriately set considering factors such as the viscosity and surface tension of the charge-transporting ink composition and the thickness of the manufactured film, and is typically about 0.1 to 15% by mass. From the viewpoint of suppressing the aggregation of charge-transporting substances and metal oxide nanoparticles in the ink composition, it is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 6% by mass or less.

[0197] In preparing the charge-transporting ink composition of the present invention, as long as the solid components are uniformly dissolved or dispersed in the solvent, the amine compound represented by formula (P1), the charge-transporting substance, the solvent, and, as needed, the metal oxide nanoparticles and dopant substances can be mixed in any order. That is, for example, any method can be used as long as the solid components are uniformly dissolved or dispersed in the solvent, provided that the solid components are uniformly dissolved or dispersed in the solvent.

[0198] When using metal oxide nanoparticles, examples include adding an aqueous or organic solvent dispersion of the metal oxide nanoparticles at any time in the above methods; and adding a pre-prepared solution containing an amine compound represented by formula (P1) and a charge-transporting substance, as well as other components or solutions thereof, to the aqueous or organic solvent dispersion of the metal oxide nanoparticles.

[0199] Note that the charge transportable substance and the metal oxide nanoparticles can be aggregated or precipitated due to the kind and amount of the solvent mixed at the time of mixing, and attention should be paid to this.

[0200] In the production of the charge transportable ink composition, heating can be appropriately performed within a range where the components do not decompose or deteriorate.

[0201] In the present application, in order to obtain a thin film having higher planarity with good reproducibility, filtration using a submicron filter or the like can be performed at an intermediate stage of the production of the charge transportable ink composition or after mixing of all the components.

[0202] By applying the above-described charge transportable ink composition to a substrate and firing, a charge transportable thin film can be formed on the substrate.

[0203] The method of applying the ink composition is not particularly limited, and examples include dipping, spin coating, transfer printing, roll coating, brushing, inkjet, spraying, slit coating, and the like, and the viscosity and surface tension of the ink composition are preferably adjusted according to the method of application.

[0204] In addition, in the case of using the charge transportable ink composition of the present application, the firing atmosphere is not particularly limited, and a thin film having a uniform film surface and high charge transportability can be obtained not only in an atmospheric atmosphere but also in a non-reactive gas such as nitrogen or in a vacuum. The firing temperature is appropriately set within a range of about 100 to 260°C in consideration of the purpose of the obtained thin film, the degree of charge transportability imparted to the obtained thin film, the kind of solvent, the boiling point, and the like, and in the case where the obtained thin film is used as a hole injection layer of an organic EL element, the temperature is preferably about 140 to 250°C, and more preferably about 145 to 240°C. Note that, at the time of firing, a temperature change of two or more stages can be given for the purpose of exhibiting higher uniform film formation or causing a reaction on the substrate, and heating can be performed using appropriate equipment such as a hot plate or an oven.

[0205] The film thickness of the charge transportable thin film is not particularly limited, and is preferably 5 to 300 nm in the case where the thin film is used as a functional layer provided between an anode and a light-emitting layer, such as a hole injection layer, a hole transport layer, or a hole injection transport layer. As a method of changing the film thickness, there are methods of changing the concentration of solid components in the charge transportable ink composition or changing the amount of solution on a substrate at the time of application.

[0206] The organic EL element of the present application has a pair of electrodes, and a charge transport layer including the above-described charge transportable thin film of the present application is provided between the electrodes.

[0207] As representative configurations of the organic EL element, the following (a) to (f) can be given, but are not limited thereto. Note that in the following configurations, an electron-blocking layer or the like can be provided as necessary between the light-emitting layer and the anode, and a hole (hole) blocking layer or the like can be provided as necessary between the light-emitting layer and the cathode. In addition, the hole-injection layer, the hole-transport layer, or the hole-injection / transport layer can have a function as an electron-blocking layer or the like, and the electron-injection layer, the electron-transport layer, or the electron-injection / transport layer can have a function as a hole (hole) blocking layer or the like. Furthermore, an arbitrary functional layer can be provided as necessary between the layers.

[0208] (a) anode / hole-injection layer / hole-transport layer / light-emitting layer / electron-transport layer / electron-injection layer / cathode

[0209] (b) anode / hole-injection layer / hole-transport layer / light-emitting layer / electron-injection / transport layer / cathode

[0210] (c) anode / hole-injection / transport layer / light-emitting layer / electron-transport layer / electron-injection layer / cathode

[0211] (d) anode / hole-injection / transport layer / light-emitting layer / electron-injection / transport layer / cathode

[0212] (e) anode / hole-injection layer / hole-transport layer / light-emitting layer / cathode

[0213] (f) anode / hole-injection / transport layer / light-emitting layer / cathode

[0214] The "hole-injection layer", "hole-transport layer", and "hole-injection / transport layer" are layers formed between the light-emitting layer and the anode, and have a function of transporting holes from the anode to the light-emitting layer. In the case where only one layer of a hole-transport material is provided between the light-emitting layer and the anode, it is a "hole-injection / transport layer", and in the case where two or more layers of a hole-transport material are provided between the light-emitting layer and the anode, the layer close to the anode is a "hole-injection layer", and the other layer is a "hole-transport layer". In particular, the hole-injection (transport) layer uses a thin film which is excellent not only in the acceptance of holes from the anode but also in the injection of holes to the hole-transport (light-emitting) layer.

[0215] The "electron-injection layer", "electron-transport layer", and "electron-injection / transport layer" are layers formed between the light-emitting layer and the cathode, and have a function of transporting electrons from the cathode to the light-emitting layer. In the case where only one layer of an electron-transport material is provided between the light-emitting layer and the cathode, it is an "electron-injection / transport layer", and in the case where two or more layers of an electron-transport material are provided between the light-emitting layer and the cathode, the layer close to the cathode is an "electron-injection layer", and the other layer is an "electron-transport layer".

[0216] The "light-emitting layer" is an organic layer having a light-emitting function, and in the case of using a doping system, contains a host material and a dopant material. At this time, the host material mainly has a function of promoting recombination of electrons and holes and confining excitons within the light-emitting layer, and the dopant material has a function of efficiently emitting excitons resulting from recombination. In the case of a phosphorescent element, the host material mainly has a function of confining excitons generated by the dopant within the light-emitting layer.

[0217] The charge-transporting thin film produced from the charge-transporting ink composition of the present application is suitable as a functional layer formed between an anode and a light-emitting layer in an organic EL element, as a hole-injection layer, a hole-transporting layer, a hole-injection-transporting layer, as a hole-injection layer, a hole-transporting layer, and as a hole-injection layer.

[0218] As the use material and the production method when producing an EL element using the charge-transporting ink composition of the present application, the following use material and production method can be exemplified, but are not limited thereto.

[0219] An example of the production method of an OLED element having a hole-injection layer containing a thin film obtained from the charge-transporting ink composition of the present application is described below. Note that, in the case of an electrode, it is preferable to perform cleaning with alcohol, pure water, or the like in advance within a range that does not adversely affect the electrode; and to perform surface treatment with UV ozone treatment, oxygen-plasma treatment, or the like.

[0220] A hole-injection layer is formed using the above-described charge-transporting ink composition on an anode substrate by the above-described method. The hole-injection layer is introduced into a vacuum evaporation device, and a hole-transporting layer, a light-emitting layer, an electron-transporting layer / hole-blocking layer, an electron-injection layer, and a cathode metal are sequentially evaporated. Alternatively, in this method, instead of forming a hole-transporting layer and a light-emitting layer by evaporation, a hole-transporting layer-forming composition containing a hole-transporting high molecule and a light-emitting layer-forming composition containing a light-emitting high molecule are used, and these layers are formed by a wet method. Note that, as necessary, an electron-blocking layer can be provided between the light-emitting layer and the hole-transporting layer.

[0221] As the anode material, a transparent electrode represented by indium tin oxide (ITO), indium zinc oxide (IZO), a metal anode composed of a metal represented by aluminum, or an alloy thereof, or the like can be exemplified, and an anode material subjected to a planarization treatment is preferable. A polythiophene derivative or a polyaniline derivative having high charge transportability can also be used.

[0222] Note that, as another metal constituting the metal anode, gold, silver, copper, indium, an alloy thereof, or the like can be exemplified, but is not limited thereto.

[0223] As a material forming a hole-transporting layer, there can be mentioned (triphenylamine) dimer derivatives, [(triphenylamine) dimer] spirodimers, N,N'-bis(naphthalen-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-naphthyl(phenyl)amino]triphenylamine (1-TNATA), and the like triarylamines, 5,5"-bis-{4-[bis(4-methylphenyl)amino]phenyl}-2,2':5',2"-terthiophene (BMA-3T) and the like oligothiophenes.

[0224] As a material forming a light-emitting layer, there can be mentioned a system in which a light-emitting material and an electron-transporting material are mixed in the following high molecular compounds, but not limited to these: metal complexes such as an aluminum complex of 8-hydroxyquinoline, a metal complex of 10-hydroxybenzo[h]quinoline, a bisstyrylbenzene derivative, a bisstyrylarylene derivative, a metal complex of (2-hydroxyphenyl)benzothiazole, a thienyl derivative, and the like low molecular light-emitting materials; poly(p-phenylenevinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], poly(3-alkylthiophene), polyvinylcarbazole, and the like.

[0225] Further, in the case where the light-emitting layer is formed by evaporation, a light-emitting dopant can be co-evaporated, and as the light-emitting dopant, there can be mentioned metal complexes such as tris(2-phenylpyridine)iridium(III) (Ir(ppy)3), perylenediimide derivatives such as rubrene, quinacridone derivatives, fused polycyclic aromatic rings such as perylene, but not limited to these.

[0226] As a material forming an electron-transporting layer / hole-blocking layer, there can be mentioned oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, phenylquinoxaline derivatives, benzimidazole derivatives, pyrimidine derivatives, and the like, but not limited to these.

[0227] As a material forming an electron-injecting layer, there can be mentioned metal oxides such as lithium oxide (Li2O), magnesium oxide (MgO), aluminum oxide (Al2O3), metal fluorides such as lithium fluoride (LiF), sodium fluoride (NaF), and the like, but not limited to these.

[0228] As a cathode material, there can be mentioned aluminum, a magnesium-silver alloy, an aluminum-lithium alloy, and the like, but not limited to these.

[0229] As a material forming an electron-blocking layer, there can be mentioned iridium tris(phenylpyrazole), and the like, but not limited to these.

[0230] As the hole-transporting polymer, poly[(9,9-dihexylfluorene-2,7-diyl)-co-(N,N'-bis{p-butylphenyl}-1,4-diaminophenylene)], poly[(9,9-dioctylfluorene-2,7-diyl)-co-(N,N'-bis{p-butylphenyl}-1,1'-biphenyl-4,4-diamine)], poly[(9,9-bis{1'-penten-5'-yl}fluorene-2,7-diyl)-co-(N,N'-bis{p-butylphenyl}-1,4-diaminophenylene)], poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine] capped with a polysilsesquioxane, poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)], and the like can be exemplified.

[0231] As the light-emitting polymer, polyfluorene derivatives such as poly(9,9-dialkylfluorene) (PDAF), polyphenylacetylene derivatives such as poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylacetylene) (MEH-PPV), polythiophene derivatives such as poly(3-alkylthiophene) (PAT), and the like can be exemplified.

[0232] As the materials constituting the anode and the cathode and the layer formed therebetween, the materials are appropriately selected in consideration of which of the element having a bottom emission structure and the element having a top emission structure is to be manufactured.

[0233] Generally, in the element having a bottom emission structure, a transparent anode is used on the substrate side, and light is extracted from the substrate side, whereas in the element having a top emission structure, a reflective anode containing a metal is used, and light is extracted from the transparent electrode (cathode) side located in the direction opposite to the substrate, and thus, for example, as the anode material, a transparent anode such as ITO is used in the manufacture of the element having a bottom emission structure, and a reflective anode such as Al / Nd is used in the manufacture of the element having a top emission structure.

[0234] As the organic EL element of the present application, in order to prevent deterioration of characteristics, sealing can be performed as needed together with a water-trapping agent or the like in accordance with a conventional method.

[0235] The charge-transporting ink composition of the present application is, as described above, suitable for use in the formation of a functional layer formed between an anode and a light-emitting layer of an organic EL element, and in addition, can also be used in the formation of a charge-transporting film in electronic elements such as an organic photoelectric conversion element, an organic thin-film solar cell, an organic perovskite photoelectric conversion element, an organic integrated circuit, an organic field-effect transistor, an organic thin-film transistor, an organic light-emitting transistor, an organic optical checker, an organic light receiver, an organic electric-field extinction element, a light-emitting electrochemical cell, a quantum dot light-emitting diode, a quantum laser, an organic laser diode, and an organic plasmon light-emitting element.

[0236] The method for improving the storage stability of the charge transportable ink composition of the present application is a method for improving the storage stability of a charge transportable ink composition containing an amine compound, a charge transportable substance, and an organic solvent, and as the amine compound, an amine compound represented by the above formula (P1) is used. The suitable conditions for the solid components such as the amine compound and the charge transportable substance, the type and amount of the organic solvent, and the like are the same as described above.

[0237] The improvement in the storage stability of the charge transportable ink composition can be evaluated in terms of the change in absorbance. Specifically, when the absorbance of the charge transportable ink composition before atmospheric exposure at a wavelength of maximum absorption (e.g., 620 nm) is set as a (initial), the absorbance of the charge transportable ink composition after exposure for 10 days is set as a (atmospheric exposure), and the difference between the absorbances before and after atmospheric exposure (a (initial) - a (atmospheric exposure)) is set as Δa, the absolute value of the change rate (%) of the absorbance = Δa / a (initial) is usually 10% or less, in a preferred embodiment, 9% or less, in a more preferred embodiment, 8% or less, in a further preferred embodiment, 7% or less, and in a still further preferred embodiment, 6% or less.

[0238] The method for improving the flatness of the charge transportable thin film of the present application is a method for improving the flatness of a charge transportable thin film obtained from a charge transportable ink composition containing an amine compound, a charge transportable substance, and an organic solvent, and the suitable conditions for the amine compound, the charge transportable substance, and the like, the type and amount of the organic solvent, the formation conditions of the charge transportable thin film, and the like are the same as described above.

[0239] The improvement in the flatness of the charge transportable thin film can be evaluated in terms of the average surface roughness Ra. Specifically, when the charge transportable thin film formed on a substrate is measured using an atomic force microscope with a measurement range of 3 μm x 3 μm, the average surface roughness Ra (nm) is usually 2.80 nm or less, in a preferred embodiment, 2.70 nm or less, in a more preferred embodiment, 2.60 nm or less, and in a preferred embodiment, 2.50 nm or less.

[0240] In the present application, the average surface roughness (Ra) of the charge transportable thin film can be measured, for example, using an atomic force microscope Park-NX10 manufactured by Park Systems Co., Ltd. and an OMCL-AC160TS10M cantilever for average surface roughness measurement manufactured by Olympus Corporation.

[0241] Example

[0242] The following examples and comparative examples more specifically illustrate the present application, but the present application is not limited to the following examples. It should be noted that the apparatus used is as described below.

[0243] (1) Coating of the charge-transporting ink composition: spin coater MS-A100 manufactured by MIKASA Corporation

[0244] (2) Measurement of the average surface roughness (Ra) of the charge-transporting thin film: atomic force microscope Park-NX10 manufactured by Park Systems Corporation and cantilever for measuring the average surface roughness OMCL-AC 160TS10M manufactured by Olympus Corporation

[0245] (3) Solution absorption spectrum measurement of the ink composition: ultraviolet-visible near-infrared spectrophotometer UV-3600 manufactured by Shimadzu Science Corporation

[0246] (4) Production of the organic EL element: multi-functional vapor deposition device system C-E2L1G1-N manufactured by Chugoku Industry Corporation

[0247] (5) Measurement of the brightness and the like of the organic EL element: multi-channel IVL measuring device manufactured by EHC Corporation

[0248] [1] Synthesis of compounds

[0249] [Production Example 1]

[0250] An amine adduct of a polymer, i.e., a polythiophene derivative, containing a repeating unit represented by formula (1a) was synthesized according to the methods described in U.S. Patent No. 8017241 and International Publication No. 2016 / 171935, respectively, in order.

[0251] [Chemical 16]

[0252]

[0253] (In the formula, a to d are the same as described above.)

[0254] [Production Example 2]

[0255] An aryl sulfonic acid compound A represented by formula (b-1) was synthesized according to the method described in International Publication No. 2006 / 025342.

[0256] [Chemical 17]

[0257]

[0258] [2] Preparation of solutions and dispersions for preparing charge-transporting ink compositions

[0259] [Preparation Example 1]

[0260] A 1,3-dimethyl-2-imidazolidinone solution containing 10 mass% of arylsulfonic acid compound A was prepared. The above solution was prepared by stirring for 1 hour at 400 rpm and 50°C using a hot stirrer.

[0261] [Preparation Example 2]

[0262] ST-OS (manufactured by Nissan Chemical Industries, Ltd.) 100 g as a water-dispersed silica sol and dipropylene glycol monomethyl ether (manufactured by Showa Denko K.K., same hereinafter) were put into an eggplant flask, and the water contained in the ST-OS was replaced with the dipropylene glycol monomethyl ether using an evaporator to obtain a silica sol (silica concentration 9.43 mass%) with dipropylene glycol monomethyl ether as a dispersion medium.

[0263] [3] Preparation of charge transportable ink composition

[0264] [Example 1-1]

[0265] A 1,3-dimethyl-2-imidazolidinone solution containing 10 mass% of arylsulfonic acid compound A was prepared. The above solution was prepared by stirring for 1 hour at 400 rpm and 50°C using a hot stirrer.

[0266] To the obtained mixture, 1.05 g of a solution obtained by adding the amine adduct of the polythiophene derivative obtained in Production Example 1 0.10 g, 1,3-dimethyl-2-imidazolidinone (manufactured by Wako Pure Chemical Industries, Ltd., same hereinafter) 4.75 g and 3-ethoxypropylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.15 g, which had been stirred for 3 hours at 80°C using a hot stirrer, was added, and stirring was performed for 30 minutes at room temperature.

[0267] Next, to the obtained mixture, the silica sol with dipropylene glycol monomethyl ether as a dispersion medium obtained in Preparation Example 2 1.78 g was added, and stirring was performed for 30 minutes at room temperature.

[0268] Finally, the obtained mixture was filtered with a PP syringe filter having a pore size of 0.2 μm to obtain a charge transportable ink composition.

[0269] [Example 1-2]

[0270] In a triangular flask were placed 1,3-dimethyl-2-imidazolidinone 3.24 g, dipropylene glycol 5.17 g and dipropylene glycol monomethyl ether 3.55 g, and stirred at room temperature for 30 minutes using a stirrer. Then, 1,3-dimethyl-2-imidazolidinone solution of arylsulfonic acid compound A obtained in Preparation Example 1 0.21 g was added, and stirred at room temperature for 30 minutes using a stirrer.

[0271] In the resulting mixture, amine adduct of polythiophene derivative obtained in Production Example 1 0.10 g, 1,3-dimethyl-2-imidazolidinone 4.75 g and 3-isopropoxypropylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.15 g were added to 1.05 g of the mixture obtained by stirring at 80°C for 3 hours using a hot stirrer, and stirred at room temperature for 30 minutes.

[0272] Next, in the resulting mixture, silica sol in which dipropylene glycol monomethyl ether was used as a dispersion medium, which was obtained in Preparation Example 2, 1.78 g was added, and stirred at room temperature for 30 minutes.

[0273] Finally, the resulting mixture was filtered with a PP syringe filter having a pore size of 0.2 μm to obtain a charge transportable ink composition.

[0274] [Comparative Example 1-1]

[0275] In a triangular flask were placed 1,3-dimethyl-2-imidazolidinone 3.24 g, dipropylene glycol 5.17 g and dipropylene glycol monomethyl ether 3.55 g, and stirred at room temperature for 30 minutes using a stirrer. Then, 1,3-dimethyl-2-imidazolidinone solution of arylsulfonic acid compound A obtained in Preparation Example 1 0.21 g was added, and stirred at room temperature for 30 minutes using a stirrer.

[0276] In the resulting mixture, amine adduct of polythiophene derivative obtained in Production Example 1 0.10 g, 1,3-dimethyl-2-imidazolidinone 4.75 g and n-butylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.15 g were added to 1.05 g of the mixture obtained by stirring at 80°C for 3 hours using a hot stirrer, and stirred at room temperature for 30 minutes.

[0277] Next, in the resulting mixture, silica sol in which dipropylene glycol monomethyl ether was used as a dispersion medium, which was obtained in Preparation Example 2, 1.78 g was added, and stirred at room temperature for 30 minutes.

[0278] Finally, the resulting mixture was filtered with a PP syringe filter having a pore size of 0.2 μm to obtain a charge transportable ink composition.

[0279] [Comparative Example 1-2]

[0280] In a triangular flask was placed 1,3-dimethyl-2-imidazolidinone 3.24 g, dipropylene glycol 5.17 g, and dipropylene glycol monomethyl ether 3.55 g, and stirred at room temperature for 30 minutes using a stirrer. Then, the 1,3-dimethyl-2-imidazolidinone solution of the arylsulfonic acid compound A obtained in Preparation Example 1 0.21 g was added, and stirred at room temperature for 30 minutes using a stirrer.

[0281] In the obtained mixture, the amine adduct of the polythiophene derivative obtained in Production Example 1 0.10 g, 1,3-dimethyl-2-imidazolidinone 4.75 g, and isopentylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.15 g were added, and stirred at 80°C for 3 hours using a hot stirrer, and stirred at room temperature for 30 minutes.

[0282] Next, to the obtained mixture was added the silica sol obtained in Preparation Example 2 using dipropylene glycol monomethyl ether as a dispersion medium 1.78 g, and stirred at room temperature for 30 minutes.

[0283] Finally, the obtained mixture was filtered with a PP syringe filter having a pore size of 0.2 μm to obtain a charge transportable ink composition.

[0284] [Comparative Example 1-3]

[0285] The amine adduct of the polythiophene derivative obtained in Production Example 1 0.10 g was added to 1,3-dimethyl-2-imidazolidinone 4.75 g and 3-aminopropanol (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.15 g, and stirred at 80°C for 3 hours using a hot stirrer, but the amine adduct of the polythiophene derivative was not sufficiently dissolved nor dispersed, and a uniform composition was not prepared to a degree usable for formation of a charge transportable film.

[0286] [Comparative Example 1-4]

[0287] The amine adduct of the polythiophene derivative obtained in Production Example 1 0.10 g was added to 1,3-dimethyl-2-imidazolidinone 4.75 g and 2-amino-l-methoxybutane (manufactured by Tokyo Chemical Industry Co., Ltd.) 0.15 g, and stirred at 80°C for 3 hours using a hot stirrer, but the amine adduct of the polythiophene derivative was not sufficiently dissolved nor dispersed, and a uniform composition was not prepared to a degree usable for formation of a charge transportable film.

[0288] [Comparative Example 1-5]

[0289] The amine adduct of the polythiophene derivative obtained in Production Example 1, 0.10 g, was added to 1,3-dimethyl-2-imidazolidinone, 4.75 g, and bis(2-ethoxyethyl)amine (manufactured by Tokyo Kasei Kogyo Co., Ltd.), 0.15 g, and stirred at 80°C for 3 hours using a hot stirrer. The amine adduct of the polythiophene derivative was not sufficiently dissolved nor dispersed, and a uniform composition was not prepared to the extent that could be used for the formation of a charge transportable thin film.

[0290] [4] Production of a charge transportable thin film and evaluation of average surface roughness Ra

[0291] [Example 2-1]

[0292] The charge transportable ink composition obtained in Example 1-1 was applied to an ITO substrate using a spin coater, and after heating at 120°C for 1 minute under the atmosphere, heating at 230°C for 15 minutes, a uniform thin film having a thickness of 30 nm was formed on the ITO substrate.

[0293] Note that, as the ITO substrate, a glass substrate of 25 mm x 25 mm x 0.7 t on which indium tin oxide (ITO) was patterned at a film thickness of 50 nm was used, and impurities on the surface were removed using an O2 plasma cleaning device (150 W, 30 seconds) before use.

[0294] [Example 2-2, Comparative Examples 2-1 to 2-2]

[0295] A uniform thin film having a thickness of 30 nm was formed on an ITO substrate in the same manner as in Example 2-1, except that the charge transportable ink composition obtained in Example 1-2, Comparative Examples 1-1 to 1-2, respectively, was used instead of the charge transportable ink composition of Example 1-1.

[0296] The average surface roughness Ra of the charge transportable thin film on the ITO substrate formed in Example 2-1, Example 2-2, Comparative Example 2-1, and Comparative Example 2-2 was evaluated using an atomic force microscope. Note that the measurement range of the atomic force microscope was 3 μm x 3 μm. The results are shown in Table 1.

[0297] [Table 1]

[0298] Average surface roughness Ra (nm) Example 2-1 2.31 Example 2-2 2.39 Comparative Example 2-1 2.94 Comparative Example 2-2 3.08

[0299] As shown in Table 1, the average surface roughness of the thin film formed from the charge transportable ink composition of the present application was lower than that of the thin film formed from the charge transportable ink composition of the comparative example. It is presumed that this is because, by using the amine compound represented by formula (P1) included in the charge transportable ink composition of the present application, more stable interaction of the amine compound with the charge transport substance can be achieved, and the aggregation of the charge transport substance in the heating step after coating the composition is moderated or inhibited.

[0300] [5] Evaluation of stability of charge transportable ink composition to atmospheric exposure

[0301] [Example 3-1]

[0302] The charge transportable ink composition obtained in Example 1-1, 0.2 g, was mixed with 1,3-dimethyl-2-imidazolidinone, 4.14 g, dipropylene glycol, 4.83 g, and dipropylene glycol monomethyl ether, 4.83 g, and the obtained mixture was subjected to absorption spectrum measurement.

[0303] Next, the charge transportable ink composition obtained in Example 1-1, 3.0 g, was added to a glass-made tube-shaped vial of 20 mL capacity, and atmospheric exposure was performed at room temperature for 10 days under the atmosphere with the cap of the vial open. The charge transportable ink composition subjected to atmospheric exposure, 0.2 g, was mixed with 1,3-dimethyl-2-imidazolidinone, 4.14 g, dipropylene glycol, 4.83 g, and dipropylene glycol monomethyl ether, 4.83 g, and the obtained mixture was subjected to absorption spectrum measurement.

[0304] Note that, in the absorption spectrum measurement, a quartz-made cuvette with an optical path length of 1 cm was used.

[0305] [Example 3-2, Comparative Examples 3-1 to 3-2]

[0306] Absorption spectrum measurement was performed in the same manner as in Example 3-1, except that the charge transportable ink compositions obtained in Example 1-2, Comparative Examples 1-1 to 1-2, respectively, were used instead of the charge transportable ink composition obtained in Example 1-1.

[0307] The measured absorption spectra are shown in Figure 1 . In addition, the absorbance of the charge transportable ink composition before atmospheric exposure (a (initial)), the absorbance of the charge transportable ink composition after exposure for 10 days (a (atmospheric exposure)), the difference in absorbance before and after atmospheric exposure (Δa), and the change rate (%) of absorbance at a wavelength of 620 nm at which there is a large absorption are shown in Table 2, respectively.

[0308] [Table 2]

[0309] a (initial) a (atmospheric exposure) Δa Example 3-1 0.371 0.352 0.019 Example 3-2 0.352 0.344 0.007 Comparative Example 3-1 0.425 0.326 0.099 Comparative Example 3-2 0.348 0.300 0.048

[0310] As Figure 1 As shown in Table 2, the change in absorbance of the charge transportable ink composition of the present application is smaller than that of the charge transportable ink composition of the comparative example. It is presumed that this is because, by using the amine compound represented by formula (P1) included in the charge transportable ink composition of the present application, stable interaction of the amine compound with the charge transport substance in the composition is enabled, and oxidation of the charge transport substance is suppressed.

[0311] [6] Manufacture and property evaluation of organic EL element

[0312] [Example 4-1]

[0313] The charge transportable ink composition obtained in Example 1-1 was applied to an ITO substrate using a spin coater, and after heating at 120°C for 1 minute under the atmosphere, heating at 230°C for 15 minutes, a uniform charge transportable thin film having a thickness of 30 nm was formed on the ITO substrate.

[0314] Note that, as the ITO substrate, a glass substrate of 25 mm x 25 mm x 0.7 t on which a patterned ITO film having a thickness of 150 nm was formed on the surface was used, and before use, the surface was cleaned of impurities using an O2 plasma cleaning device (150 W, 30 seconds).

[0315] Next, on the charge transportable thin film formed on the ITO substrate, an electron blocking material HTEB-01 manufactured by Kanto Chemical Co., Inc. was deposited at a rate of 0.2 nm / sec to a thickness of 10 nm, and further, a light emitting layer host material NS60 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. and a light emitting layer dopant material Ir(ppy)3 were co-deposited thereon. In the case of the co-deposition, the deposition rate was controlled so that the concentration of Ir(ppy)3 was 6%, and the materials were laminated to a thickness of 40 nm. Next, thin films of Alq3, lithium fluoride, and aluminum were sequentially laminated, and an organic EL element was obtained. At this time, in terms of the deposition rate, for Alq3 and aluminum, the deposition was performed at a rate of 0.2 nm / sec, and for lithium fluoride, the deposition was performed at a rate of 0.02 nm / sec, and the thicknesses were set to 20 nm, 0.5 nm, and 80 nm, respectively. - 5 Pa), at a rate of 0.2 nm / sec to a thickness of 30 nm.

[0316] On the film of α-NPD, an electron blocking material HTEB-01 manufactured by Kanto Chemical Co., Inc. was deposited to a thickness of 10 nm, and further, a light emitting layer host material NS60 manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. and a light emitting layer dopant material Ir(ppy)3 were co-deposited thereon. In the case of the co-deposition, the deposition rate was controlled so that the concentration of Ir(ppy)3 was 6%, and the materials were laminated to a thickness of 40 nm. Next, thin films of Alq3, lithium fluoride, and aluminum were sequentially laminated, and an organic EL element was obtained. At this time, in terms of the deposition rate, for Alq3 and aluminum, the deposition was performed at a rate of 0.2 nm / sec, and for lithium fluoride, the deposition was performed at a rate of 0.02 nm / sec, and the thicknesses were set to 20 nm, 0.5 nm, and 80 nm, respectively.

[0317] Note that the organic EL element was sealed with a sealing substrate to prevent deterioration of characteristics due to oxygen, water, and the like in the air, and the characteristics were evaluated. The sealing was performed according to the following procedure. The organic EL element was enclosed between the sealing substrates in a nitrogen atmosphere having an oxygen concentration of 2 ppm or lower and a dew point of -76 °C or lower, and the sealing substrates were bonded with an adhesive (manufactured by MORESCO, MORESCO MOISTURE CUT WB90US (P)). At this time, a water capturing agent (manufactured by Dynic Corporation, HD-071010W-40) was enclosed in the sealing substrates together with the organic EL element. After the bonded sealing substrates were irradiated with UV light (wavelength: 365 nm, irradiation amount: 6000 mJ / cm2), the adhesive was cured by annealing treatment at 80 °C for 1 hour. 2 ) after the bonded sealing substrates were irradiated with UV light (wavelength: 365 nm, irradiation amount: 6000 mJ / cm2), the adhesive was cured by annealing treatment at 80 °C for 1 hour.

[0318] [Example 4-2]

[0319] An organic EL element was obtained in the same manner as in Example 4-1, except that the charge transportable ink composition obtained in Example 1-2 was used instead of the charge transportable ink composition obtained in Example 1-1.

[0320] For each of the elements obtained in Example 4-1 and Example 4-2, the driving voltage, the current density and the luminous efficiency at the time of driving at a luminance of 10000 cd / m 2 , and the half-life of the luminance (time required for the initial luminance of 10000 cd / m 2 to reach half) were measured. The results are shown in Table 3.

[0321] [Table 3]

[0322]

[0323] The organic EL elements obtained in Example 4-1 and Example 4-2 each showed good element characteristics.

Claims

1. A charge-transfer ink composition, characterized in that, Includes: amine compounds, charge-transporting substances, and organic solvents represented by the following formula (P1). [Chemistry 1] In the formula, R m R is an alkyl group selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, and n-hexyl. n It is any alkylene group selected from methylene, ethylene, propylene, trimethylene, and tetramethylene. The charge-transporting substance is a polythiophene derivative or its amine adduct containing repeating units represented by the following formula (1). [Chemistry 2] In the formula, R 1 It is a sulfonic acid group, R 2 It is an alkoxy group with 1 to 40 carbon atoms or -O-[ZO]. p -R e , or for the R 1 and R 2 The bonded -OYO-, where Y is an alkylene group with 1 to 40 carbon atoms that may contain ether bonds and can be substituted with sulfonic acid groups, Z is an alkylene group with 1 to 40 carbon atoms that can be substituted with halogen atoms, p is an integer greater than or equal to 1, and R... e It is a hydrogen atom, an alkyl group having 1 to 40 carbon atoms, a fluoroalkyl group having 1 to 40 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

2. The charge-transfer ink composition according to claim 1, further comprising a dopant substance.

3. The charge-transfer ink composition according to claim 2, wherein, The dopant material comprises at least one selected from arylsulfonic acid compounds and heteropolyacid compounds.

4. The charge-transfer ink composition according to any one of claims 1 to 3, further comprising metal oxide nanoparticles.

5. A charge-transfer thin film obtained from the charge-transfer ink composition according to any one of claims 1 to 4.

6. An electronic component having the charge-transporting thin film according to claim 5.

7. The electronic component according to claim 6, wherein, The charge transport thin film is a hole injection layer, a hole transport layer, or a hole injection transport layer.

8. The electronic component according to claim 6 is an organic electroluminescent element.

9. A method for improving the storage stability of a charge-transfer ink composition, characterized in that: As the amine compound, an amine compound represented by the following formula (P1) is used. [Chemistry 3] In the formula, R m R is an alkyl group selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, and n-hexyl. n It is any alkylene group selected from methylene, ethylene, propylene, trimethylene, and tetramethylene. The charge-transporting substance is a polythiophene derivative or its amine adduct containing repeating units represented by the following formula (1). [Chemistry 4] In the formula, R 1 It is a sulfonic acid group, R 2 It is an alkoxy group with 1 to 40 carbon atoms or -O-[ZO]. p -R e , or for the R 1 and R 2 The bonded -OYO-, where Y is an alkylene group with 1 to 40 carbon atoms that may contain ether bonds and can be substituted with sulfonic acid groups, Z is an alkylene group with 1 to 40 carbon atoms that can be substituted with halogen atoms, p is an integer greater than or equal to 1, and R... e It is a hydrogen atom, an alkyl group having 1 to 40 carbon atoms, a fluoroalkyl group having 1 to 40 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

10. A method for improving the flatness of a charge-transfer thin film, comprising a charge-transfer ink composition containing an amine compound, a charge-transfer substance, and an organic solvent, characterized in that... As the amine compound, an amine compound represented by the following formula (P1) is used. [Chemistry 5] In the formula, R m R is an alkyl group selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, and n-hexyl. n It is any alkylene group selected from methylene, ethylene, propylene, trimethylene, and tetramethylene. The charge-transporting substance is a polythiophene derivative or its amine adduct containing repeating units represented by the following formula (1). [Chemistry 6] In the formula, R 1 It is a sulfonic acid group, R 2 It is an alkoxy group with 1 to 40 carbon atoms or -O-[ZO]. p -R e , or for the R 1 and R 2 The bonded -OYO-, where Y is an alkylene group with 1 to 40 carbon atoms that may contain ether bonds and can be substituted with sulfonic acid groups, Z is an alkylene group with 1 to 40 carbon atoms that can be substituted with halogen atoms, p is an integer greater than or equal to 1, and R... e It is a hydrogen atom, an alkyl group having 1 to 40 carbon atoms, a fluoroalkyl group having 1 to 40 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

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