Charge transport ink composition

Abstract

As a charge transport ink composition that enables the achievement of a film that has charge transport characteristics, high transparency in the visible light region and excellent flatness, while being stable in terms of exposure to the atmosphere, the present invention provides a charge transport ink composition which is characterized by containing an amine compound represented by formula (P1), a charge transport material and an organic solvent. (In the formula, Rm 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; Rn 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 alternatively, Rm and Rn combine with each other to form an alkane triyl group having 3 to 40 carbon atoms. Meanwhile, the alkylene group having 1 to 20 carbon atoms and the alkenylene group having 2 to 20 carbon atoms for Rn, and the alkane triyl group for combined Rm and Rn are limited to those which form a -CH2-NH2 group if combined with -NH2 in formula (P1).)

Description

[Technical Field]

[0001] The present invention relates to a charge transport ink composition. [Background technology]

[0002] Organic electroluminescence (hereinafter referred to as OLED) elements have attracted attention due to their various advantages, such as high contrast, energy saving, and flexibility, and are being put to practical use in fields such as displays and lighting. OLED elements use multiple functional thin films, one of which is the hole injection layer, which handles the exchange of charges between the anode and the hole transport layer or light-emitting layer, and plays an important role in achieving low-voltage operation and high brightness in OLED elements.

[0003] Manufacturing methods for organic EL devices are broadly divided into dry processes, such as vapor deposition, and wet processes, such as spin coating and inkjet printing. Comparing these processes from the perspective of increasing the device area, wet processes can more efficiently produce films with high flatness over large areas than dry processes. Therefore, given the current demand for large-area manufacturing of organic EL devices, it is important to provide hole injection layers and other layers with excellent functionality that can be formed by wet processes.

[0004] One of the functions required for charge-transporting thin films such as hole injection layers is high transparency in the visible light region. In recent years, high transparency in the visible light region has been required because coloring of charge-transporting thin films reduces the color purity and color reproducibility of organic EL devices.

[0005] In view of this, various studies have been conducted to achieve high transparency in the visible light region. In Patent Document 1, a charge transporting thin film having high transparency in the visible light region is formed by using a composition containing metal oxide nanoparticles.

[0006] On the other hand, charge transport thin films such as hole injection layers are required to have excellent charge transport properties, high transparency in the visible light region, as well as film flatness and ink composition stability. Non-Patent Document 1 shows that reducing the surface roughness of the film improves the characteristics of organic EL devices. Furthermore, charge transport inks are generally susceptible to the effects of oxygen and moisture, and there is a concern that their performance may change due to oxidation or decomposition of compounds in the ink. Therefore, it is important from the perspective of reliability that charge transport inks are stable against exposure to the atmosphere. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2018 / 135582 [Non-patent literature]

[0008] [Non-Patent Document 1] Korean Journal of Chemical Engineering 2005, Vol. 22, p.643-647 Summary of the Invention [Problem to be solved by the invention]

[0009] With the recent development of the organic electroluminescence (EL) field, the performance requirements for functional thin films, including hole injection layers, that can be deposited using wet processes are increasing.

[0010] The present invention has been made in view of the above background, and an object of the present invention is to provide a charge transporting ink composition that has charge transport properties, gives a film with excellent flatness, and is stable against exposure to the atmosphere. [Means for solving the problem]

[0011] As a result of extensive research, the present inventors have found that when an amine compound is added to a charge transport ink composition containing a charge transport substance and an organic solvent, such as the composition disclosed in Patent Document 1, the use of an amine compound having a specific structure as the amine compound improves the flatness of the charge transport thin film and also improves the stability of the ink against exposure to the atmosphere, and have completed the present invention.

[0012] That is, the present invention provides the following charge transporting ink composition. 1. A charge transporting ink composition comprising an amine compound represented by the following formula (P1), a charge transporting substance, and an organic solvent: [ka] (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, and 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 bonded to each other to form an alkanetriyl group having 3 to 40 carbon atoms, and R n an 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 alkanetriyl group is limited to one that forms a —CH—NH group when bonded to —NH in formula (P1). 2. R above m is an alkyl group having 1 to 20 carbon atoms, and the R n is an alkylene group having 1 to 20 carbon atoms. 3. The charge transporting ink composition of 1 or 2, wherein the charge transporting substance is a polythiophene derivative containing a repeating unit represented by the following formula (1) or an amine adduct thereof: [ka] (In the formula, R 1 and R 2are 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-[ZO] p -R e or a sulfonic acid group, or R 1 and R 2 are bonded to each other, Y is an alkylene group having 1 to 40 carbon atoms which may contain an ether bond and which may be substituted with a sulfonic acid group, Z is an alkylene group having 1 to 40 carbon atoms which may be substituted with a halogen atom, p is an integer of 1 or more, and 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. 4. R above 1 is a sulfonic acid group, and the above R 2 is an alkoxy group having 1 to 40 carbon atoms or -O-[ZO] p -R e or the above R 1 and R 2 The charge transport ink composition of 3, wherein -OYO- is formed by bonding. 5. A charge transport ink composition according to any one of 1 to 4, further comprising a dopant substance. 6. The charge transport ink composition of 5, wherein the dopant substance comprises at least one selected from the group consisting of arylsulfonic acid compounds and heteropolyacid compounds. 7. The charge transport ink composition of any one of 1 to 6, further comprising metal oxide nanoparticles. 8. A charge-transporting thin film obtained from the charge-transporting ink composition of any one of 1 to 7. 9. An electronic device having a charge transport thin film of 8. 10. An electronic device in 9 that is an organic electroluminescent device. 11. A method for improving the storage stability of a charge transport ink composition comprising an amine compound, a charge transport substance, and an organic solvent, wherein the amine compound is an amine compound represented by the following formula (P1): [ka] (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, and 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 bonded to each other to form an alkanetriyl group having 3 to 40 carbon atoms, and R n an 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 alkanetriyl group is limited to one that forms a —CH—NH group when bonded to —NH in formula (P1). 12. A method for improving the flatness of a charge-transporting thin film obtained from a charge-transporting ink composition containing an amine compound, a charge-transporting substance, and an organic solvent, comprising: A method for improving the flatness of a charge-transporting thin film, characterized in that an amine compound represented by the following formula (P1) is used as the amine compound: [ka] (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, and 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 bonded to each other to form an alkanetriyl group having 3 to 40 carbon atoms, and R n an alkylene group having 1 to 20 carbon atoms and an alkenylene group having 2 to 20 carbon atoms, and R mand R n The alkanetriyl group is limited to one that forms a —CH—NH group when bonded to —NH in formula (P1). [Effects of the Invention]

[0013] By using the charge-transporting ink composition of the present invention, a charge-transporting thin film with excellent flatness can be obtained. Furthermore, the charge-transporting ink composition of the present invention has excellent stability against exposure to the atmosphere. This charge-transporting thin film can be suitably used as a thin film for electronic devices, including organic electroluminescence (EL) devices. [Brief explanation of the drawings]

[0014] [Figure 1] 1 shows absorption spectra of charge transporting ink compositions obtained in Examples and Comparative Examples. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention will be described in more detail below. The charge transport ink composition of the present invention comprises an amine compound represented by the following formula (P1), a charge transport material, and an organic solvent. In the present invention, the term "solid content" in relation to the charge transport ink composition of the present invention refers to components other than the solvent contained in the composition. Charge transportability is synonymous with conductivity and hole transportability. The charge transport ink composition of the present invention may itself have charge transportability, or a solid film obtained using the composition may have charge transportability.

[0016] [ka]

[0017] 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, and R nrepresents 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 bonded to each other to form an alkanetriyl group having 3 to 40 carbon atoms, and R n an 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 alkanetriyl group is limited to those which form a -CH2-NH2 group when bonded to -NH2 in formula (P1).

[0018] The alkyl group having 1 to 20 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, an n-tridecyl group, an n-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, an n-heptadecyl group, an n-octadecyl group, an n-nonadecyl group, and an n-eicosanyl group.

[0019] Examples of alkenyl groups having 2 to 20 carbon atoms include 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, and n-1-eicosenyl groups.

[0020] Examples of the aryl group having 6 to 20 carbon atoms include a phenyl group, a tolyl group, a 1-naphthyl group, a 2-naphthyl group, a 1-anthryl group, a 2-anthryl group, a 9-anthryl group, a 1-phenanthryl group, a 2-phenanthryl group, a 3-phenanthryl group, a 4-phenanthryl group, and a 9-phenanthryl group, with a phenyl group, a tolyl group, and a naphthyl group being preferred.

[0021] The alkylene group having 1 to 20 carbon atoms is a divalent group derived by removing two hydrogen atoms from an alkane, and may be linear, branched, or cyclic. Specific examples thereof include a methylene group, an ethylene group, a propylene group, a trimethylene group, a tetramethylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, a decylene group, an undecylene group, a dodecylene group, a tridecylene group, a tetradecylene group, a pentadecylene group, a hexadecylene group, a heptadecylene group, an octadecylene group, a nonadecylene group, and an eicosanylene group.

[0022] The alkenylene group having 2 to 20 carbon atoms is a divalent group derived by removing two hydrogen atoms from an alkene, and examples thereof include a vinylene group, a propenylene group, a butenylene group, a pentenylene group, a hexenylene group, a heptenylene group, an octenylene group, a nonenylene group, a decenylene group, an undecenylene group, a dodecenylene group, a tridecenylene group, a tetradecenylene group, a pentadecenylene group, a hexadecenylene group, a heptadecenylene group, an octadecenylene group, a nonadecenylene group, and an icocenylene group.

[0023] Examples of the arylene group having 6 to 20 carbon atoms include groups in which one hydrogen atom has been removed from the specific examples of the aryl group having 6 to 12 carbon atoms, such as a phenylene group, a naphthylene group, and a biphenylylene group.

[0024] The alkanetriyl group having 3 to 40 carbon atoms is a trivalent group derived by removing a hydrogen atom from an alkane, and examples thereof include a group represented by the following formula (K1).

[0025] [ka] (In the formula, n r represents an integer from 0 to 10, and n c represents an integer of 1 to 10, and * represents a bond.

[0026] Above R mAs the alkyl group, an alkyl group having 1 to 20 carbon atoms is preferable, an alkyl group having 1 to 10 carbon atoms is more preferable, an alkyl group having 1 to 8 carbon atoms is even more preferable, and an alkyl group having 1 to 5 carbon atoms is even more preferable.

[0027] Above R n As the alkylene group, an alkylene group having 1 to 20 carbon atoms is preferred, an alkylene group having 1 to 10 carbon atoms is more preferred, an alkylene group having 1 to 8 carbon atoms is even more preferred, and an alkylene group having 1 to 5 carbon atoms is even more preferred.

[0028] Above n r is preferably 1 to 3, more preferably 1 to 2, and even more preferably 1, and the above n c is preferably 1 to 3, more preferably 1 to 2, and even more preferably 1. Above n r and n c As a combination of r and n c are both 1 to 3, and more preferably n r and n c are both 1 to 2, and more preferably n r is 1 to 2, and n c is 1, and more preferably n r and n c are both 1.

[0029] Specific examples of the amine compound represented by formula (P1) include, but are not limited to, the following compounds:

[0030] [ka]

[0031] In the charge-transporting ink composition of the present invention, the content of the amine compound represented by formula (P1) is not particularly limited, but from the viewpoints of stability against exposure to the atmosphere and obtaining a thin film with good reproducibility and excellent flatness, the content is about 0.01 to 10 times by mass, preferably about 0.01 to 8 times by mass, more preferably about 0.01 to 6 times by mass, and even more preferably about 0.01 to 4 times by mass relative to 1 unit of the charge-transporting substance.

[0032] The charge transporting substance used in the present invention is not particularly limited, and can be appropriately selected from charge transporting compounds, charge transporting oligomers, charge transporting polymers, etc. used in the field of organic EL devices. Specific examples thereof include various charge transporting compounds and charge transporting oligomers such as arylamine derivatives such as oligoaniline derivatives, N,N'-diarylbenzidine derivatives and N,N,N',N'-tetraarylbenzidine derivatives, thiophene derivatives such as oligothiophene derivatives, thienothiophene derivatives and thienobenzothiophene derivatives, and pyrrole derivatives such as oligopyrrole, and charge transporting polymers such as polythiophene derivatives, polyaniline derivatives and polypyrrole derivatives, with polythiophene derivatives being particularly preferred. In a preferred embodiment, the charge transporting substance is a polythiophene derivative containing a repeating unit represented by formula (1) or an amine adduct thereof.

[0033] [ka]

[0034] 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-[ZO] p -R e or a sulfonic acid group, or R 1 and R 2are bonded to each other, Y is an alkylene group having 1 to 40 carbon atoms which may contain an ether bond and which may be substituted with a sulfonic acid group, Z is an alkylene group having 1 to 40 carbon atoms which may be substituted with a halogen atom, p is an integer of 1 or more, and 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.

[0035] The alkyl group having 1 to 40 carbon atoms may be linear, branched, or cyclic, and specific examples include the alkyl groups having 1 to 20 carbon atoms exemplified above, as well as behenyl, triacontyl, and tetracontyl groups. In the present invention, alkyl groups having 1 to 18 carbon atoms are preferred, and alkyl groups having 1 to 8 carbon atoms are more preferred.

[0036] The fluoroalkyl group having 1 to 40 carbon atoms is not particularly limited as long as it is an alkyl group having 1 to 40 carbon atoms in which at least one hydrogen atom on a carbon atom is substituted with a fluorine atom, and specific examples thereof include a fluoromethyl group, a difluoromethyl group, a perfluoromethyl group, a 1-fluoroethyl group, a 2-fluoroethyl group, a 1,2-difluoroethyl group, a 1,1-difluoroethyl group, a 2,2-difluoroethyl group, a 1,1,2-trifluoroethyl group, a 1,2,2-trifluoroethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2-tetrafluoroethyl group, a 1,2,2,2-tetrafluoroethyl group, a perfluoroethyl group, a 1-fluoropropyl group, a 2-fluoropropyl group, a 3-fluoropropyl group, a 1,1-difluoropropyl group, a 1,2-difluoropropyl group, a 1,3-difluoropropyl group, a 2,2-difluoropropyl group, a 2,3-difluoropropyl group, a 3,3-difluoropropyl group, a 1,1,2-trifluoropropyl group, 1,1,3-trifluoropropyl group, 1,2,3-trifluoropropyl group, 1,3,3-trifluoropropyl group, 2,2,3-trifluoropropyl group, 2,3,3-trifluoropropyl group, 3,3,3-trifluoropropyl group, 1,1,2,2-tetrafluoropropyl group, 1,1,2,3-tetrafluoropropyl group, 1,2,2,3-tetrafluoropropyl group, 1,3,3,3-tetrafluoropropyl group, 2,2,3,3-tetrafluoropropyl group, 2 ,3,3,3-tetrafluoropropyl group, 1,1,2,2,3-pentafluoropropyl group, 1,2,2,3,3-pentafluoropropyl group, 1,1,3,3,3-pentafluoropropyl group, 1,2,3,3,3-pentafluoropropyl group, 2,2,3,3,3-pentafluoropropyl group, perfluoropropyl group, perfluorobutyl group, perfluoropentyl group, perfluorohexyl group, perfluoroheptyl group, and perfluorooctyl group.

[0037] The alkoxy group having 1 to 40 carbon atoms may have a linear, branched, or cyclic alkyl group, and specific examples thereof include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, a c-propoxy group, an n-butoxy group, an i-butoxy group, an s-butoxy group, a t-butoxy group, an n-pentoxy group, an n-hexoxy group, an n-heptyloxy group, an n-octyloxy group, an n-nonyloxy group, an n-decyloxy group, an n-undecyloxy group, an n-dodecyloxy group, an n-tridecyloxy group, an n-tetradecyloxy group, an n-pentadecyloxy group, an n-hexadecyloxy group, an n-heptadecyloxy group, an n-octadecyloxy group, an n-nonadecyloxy group, and an n-eicosanyloxy group.

[0038] The fluoroalkoxy group having 1 to 40 carbon atoms is not particularly limited as long as it is an alkoxy group having 1 to 40 carbon atoms in which at least one hydrogen atom on a carbon atom is substituted with a fluorine atom, and specific examples thereof include a fluoromethoxy group, a difluoromethoxy group, a perfluoromethoxy group, a 1-fluoroethoxy group, a 2-fluoroethoxy group, a 1,2-difluoroethoxy group, a 1,1-difluoroethoxy group, a 2,2-difluoroethoxy group, and a 1,1,2-trifluoroethoxy group. , 1,2,2-trifluoroethoxy group, 2,2,2-trifluoroethoxy group, 1,1,2,2-tetrafluoroethoxy group, 1,2,2,2-tetrafluoroethoxy group, perfluoroethoxy group, 1-fluoropropoxy group, 2-fluoropropoxy group, 3-fluoropropoxy group, 1,1-difluoropropoxy group, 1,2-difluoropropoxy group, 1,3-difluoropropoxy group, 2,2-difluoropropoxy group, 2,3-difluoropropoxy group, 3 ,3-difluoropropoxy group, 1,1,2-trifluoropropoxy group, 1,1,3-trifluoropropoxy group, 1,2,3-trifluoropropoxy group, 1,3,3-trifluoropropoxy group, 2,2,3-trifluoropropoxy group, 2,3,3-trifluoropropoxy group, 3,3,3-trifluoropropoxy group, 1,1,2,2-tetrafluoropropoxy group, 1,1,2,3-tetrafluoropropoxy group, 1,2,2,3-tetrafluoropropoxy group Examples thereof include a silyl group, a 1,3,3,3-tetrafluoropropoxy group, a 2,2,3,3-tetrafluoropropoxy group, a 2,3,3,3-tetrafluoropropoxy group, a 1,1,2,2,3-pentafluoropropoxy group, a 1,2,2,3,3-pentafluoropropoxy group, a 1,1,3,3,3-pentafluoropropoxy group, a 1,2,3,3,3-pentafluoropropoxy group, a 2,2,3,3,3-pentafluoropropoxy group, and a perfluoropropoxy group.

[0039] The alkylene group having 1 to 40 carbon atoms may be linear, branched, or cyclic, and specific examples thereof include the same groups as those exemplified above.

[0040] Examples of the aryl group having 6 to 20 carbon atoms include the same groups as those exemplified above. In the present invention, a phenyl group, a tolyl group, and a naphthyl group are preferred.

[0041] Examples of the aryloxy group having 6 to 20 carbon atoms include a phenoxy group, an anthracenoxy group, a naphthoxy group, a phenanthrenoxy group, and a fluorenoxy group.

[0042] Halogen atoms include fluorine atoms, chlorine atoms, bromine atoms and iodine atoms.

[0043] In the above formula (1), R 1 and R 2 are each independently a hydrogen atom, a fluoroalkyl group having 1 to 40 carbon atoms, an alkoxy group having 1 to 40 carbon atoms, or —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 is preferably -OYO-, which is formed by bonding. R a ~R d are each independently 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, and specific examples of these groups are the same as those listed above. Among them, R a ~R d are preferably each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a fluoroalkyl group having 1 to 8 carbon atoms, or a phenyl group. R e is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a fluoroalkyl group having 1 to 8 carbon atoms, or a phenyl group, and is preferably a hydrogen atom, a methyl group, a propyl group, or a butyl group. Furthermore, p is preferably 1 to 5, and more preferably 1, 2 or 3.

[0044] R f represents 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, but is preferably a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a fluoroalkyl group having 1 to 8 carbon atoms, or a phenyl group, and more preferably -CHCF.

[0045] In the present invention, 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-[ZO] p -R e , more preferably —O[C(R a R b )-C(R c R d )-O] p -R e -OR f , and even more 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 are combined together to form -OYO-.

[0046] For example, the polythiophene derivative according to a preferred embodiment of the present invention is R 1 is a sulfonic acid group, and R 2 contains a repeating unit other than a sulfonic acid group, or R 1 and R 2 The repeating unit includes a repeating unit -OYO- formed by bonding of the following. Preferably, the polythiophene derivative is R 1 is a sulfonic acid group, and R 2 is an alkoxy group having 1 to 40 carbon atoms or -O-[ZO] p -Re or R 1 and R 2 The repeating unit includes a repeating unit -OYO- formed by bonding of the following. More preferably, the polythiophene derivative is R 1 is a sulfonic acid group, and R 2 But -O[C(R a R b )-C(R c R d )-O] p -R e -OR f The repeating unit is Even more preferably, the polythiophene derivative is R 1 is a sulfonic acid group, and R 2 But -O[C(R a R b )-C(R c R d )-O] p -R e or R 1 and R 2 The repeating unit includes a repeating unit -OYO- formed by bonding of the following. More preferably, the polythiophene derivative is R 1 is a sulfonic acid group, and R 2 is —O—CH2CH2—O—CH2CH2—O—CH3, —O—CH2CH2—O—CH2CH2—OH, or —O—CH2CH2—OH, or R 1 and R 2 are bonded to each other to form repeating units which are groups represented by the following formulae (Y1) and (Y2).

[0047] [ka]

[0048] Preferred specific examples of the polythiophene derivative include polythiophenes containing at least one repeating unit represented by the following formulas (1-1) to (1-5).

[0049]

Chem.

[0050] Further, examples of the preferred structure of the above polythiophene derivative include a polythiophene derivative having a structure represented by the following formula (1a). In the following formula, each unit may be randomly bonded or bonded as a block polymer.

[0051]

Chem.

[0052] In the formula, a to d represent the molar ratio of each unit, and satisfy 0 ≦ a ≦ 1, 0 ≦ b ≦ 1, 0 < a + b ≦ 1, 0 ≦ c < 1, 0 ≦ d < 1, and a + b + c + d = 1.

[0053] Furthermore, the above polythiophene derivative may be a homopolymer or a copolymer (including statistical, random, gradient, and block copolymers). As the polymer containing monomer A and monomer B, the block copolymer includes, for example, an A-B diblock copolymer, an A-B-A triblock copolymer, and an (AB) m - multiblock copolymer. The polythiophene may contain repeating units derived from other types of monomers (such as thienothiophene, selenophene, pyrrole, furan, tellurophene, aniline, arylamine, and arylene (such as phenylene, phenylenevinylene, and fluorene, etc.)).

[0054] In the present invention, 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, even more preferably 90 mol% or more, still more preferably 95 mol% or more, and most preferably 100 mol% among all the repeating units contained in the polythiophene derivative.

[0055] In the present invention, depending on the purity of the starting monomers used in the polymerization, the polymer formed may contain repeating units derived from impurities. In the present invention, the term "homopolymer" means a polymer containing repeating units derived from one type of monomer, but may also contain repeating units derived from impurities. In the present invention, the polythiophene derivative is preferably a polymer in which essentially all repeating units are repeating units represented by the above formula (1), and more preferably a polymer containing at least one of the repeating units represented by the above formulas (1-1) to (1-5).

[0056] In the present invention, when the polythiophene derivative contains a repeating unit having a sulfonic acid group, it is preferable to convert the polythiophene derivative into an amine adduct in which an amine compound is added to at least a part of the sulfonic acid groups contained in the polythiophene derivative, from the viewpoint of further improving solubility and dispersibility in organic solvents.

[0057] Amine compounds that can be used to form the amine adduct include methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, s-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, and n-octylamine. monoalkylamine compounds such as n-octadecylamine, n-nonadecylamine, and n-eicosanylamine; primary amine compounds such as monoarylamine compounds such as aniline, tolylamine, 1-naphthylamine, 2-naphthylamine, 1-anthrylamine, 2-anthrylamine, 9-anthrylamine, 1-phenanthrylamine, 2-phenanthrylamine, 3-phenanthrylamine, 4-phenanthrylamine, and 9-phenanthrylamine; primary amine compounds such as N-ethylmethylamine, N-methyl-n-propylamine, N-methylisopropylamine, and N-methylisopropylamine; N-ethyl-n-butylamine, N-methyl-s-butylamine, N-methyl-t-butylamine, N-methylisobutylamine, diethylamine, N-ethyl-n-propylamine, N-ethylisopropylamine, N-ethyl-n-butylamine, N-ethyl-s-butylamine, N-ethyl-t-butylamine, dipropylamine, Nn-propylisopropylamine, Nn-propyl-n-butylamine, Nn-propyl-s-butylamine, diisopropylamine, Nn-butylisopropylamine, Nt-butylisopropylamine, di(n-butyl) dialkylamine compounds such as di(s-butyl)amine, di(s-butyl)amine, 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, and octamethyleneimine;Diphenylamine, N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine, 1,1'-dinaphthylamine, 2,2'-dinaphthylamine, 1,2'-dinaphthylamine, carbazole, 7H-benzo[c]carbazole, 11H-benzo[a]carbazole, 7H-dibenzo[c,g]carbazole, 13H-dibenzo[a,i]carbazole and other diarylamine compounds; N-methylaniline, N-ethylaniline, Nn-propylaniline, N-iso ... secondary amine compounds such as alkylarylamine compounds, such as N,N-isopropylaniline, Nn-butylaniline, Ns-butylaniline, N-isobutylaniline, N-methyl-1-naphthylamine, N-ethyl-1-naphthylamine, Nn-propyl-1-naphthylamine, indoline, isoindoline, 1,2,3,4-tetrahydroquinoline, and 1,2,3,4-tetrahydroisoquinoline; Trialkylamine compounds such as dimethylisopropylamine, N,N-dimethyl-n-butylamine, N,N-dimethyl-s-butylamine, N,N-dimethyl-t-butylamine, N,N-dimethylisobutylamine, N,N-diethylmethylamine, N-methyldi(n-propyl)amine, N-methyldiisopropylamine, N-methyldi(n-butyl)amine, N-methyldiisobutylamine, triethylamine, N,N-diethyl-n-butylamine, N,N-diisopropylethylamine, N,N-di(n-butyl)ethylamine, tri(n-propyl)amine, tri(i-propyl)amine, tri(n-butyl)amine, tri(i-butyl)amine, 1-methylacetidine, 1-methylpyrrolidine, and 1-methylpiperidine; triarylamine compounds such as triphenylamine; alkyldiarylamine compounds such as N-methyldiphenylamine, N-ethyldiphenylamine, 9-methylcarbazole, and 9-ethylcarbazole;Examples of the tertiary amine compounds include dialkylarylamine compounds such as N,N-diethylaniline, N,N-di(n-propyl)aniline, N,N-di(i-propyl)aniline, and N,N-di(n-butyl)aniline. However, taking into consideration the balance between the solubility of the amine adduct and the charge transport properties of the resulting charge transport thin film, tertiary amine compounds are preferred, trialkylamine compounds are more preferred, and triethylamine is even more preferred; The amine adduct can be obtained by adding the polythiophene derivative to the amine itself or a solution thereof and stirring thoroughly.

[0058] In the present invention, the above polythiophene derivative or its amine adduct may be treated with a reducing agent before use. In polythiophene derivatives or their amine adducts, some of the repeating units constituting them may have an oxidized chemical structure called a "quinoid structure." The term "quinoid structure" is used in contrast to the term "benzenoid structure." The latter is a structure containing an aromatic ring, while the former refers to a structure in which a double bond within the aromatic ring moves out of the ring (resulting in the disappearance of the aromatic ring), resulting in the formation of two exocyclic double bonds conjugated with other double bonds remaining within the ring. Those skilled in the art can easily understand the relationship between these two structures from the relationship between the structures of benzoquinone and hydroquinone. Quinoid structures for the repeating units of various conjugated polymers are well known to those skilled in the art. As an example, the quinoid structure corresponding to the repeating unit of a polythiophene derivative containing the repeating unit represented by the above formula (1) is shown below in formula (1').

[0059] [ka] (In the formula, R 1 and R 2 is as defined in the above formula (1).

[0060] This quinoid structure is formed by a process in which a polythiophene derivative containing the repeating unit represented by formula (1) undergoes an oxidation reaction with a dopant, a process known as a doping reaction, and forms part of structures known as "polaron structures" and "bipolaron structures" that impart charge transport properties to the polythiophene derivative. These structures are known. The introduction of a "polaron structure" and / or a "bipolaron structure" is essential for the fabrication of organic EL devices. In fact, this is achieved by intentionally inducing the doping reaction during the baking process of a thin film formed from a charge transport ink composition during the fabrication of the organic EL device. The presence of a quinoid structure in the polythiophene derivative prior to the doping reaction is thought to be due to an unintended oxidation reaction, equivalent to the doping reaction, occurring during the polythiophene derivative's manufacturing process (particularly the sulfonation step therein).

[0061] There is a correlation between the amount of quinoid structures contained in the polythiophene derivative and the solubility and dispersibility of the polythiophene derivative in organic solvents; as the amount of quinoid structures increases, the solubility and dispersibility tend to decrease. Therefore, the introduction of quinoid structures after a thin film is formed from the charge-transporting ink composition does not cause any problems. However, if an excessive amount of quinoid structures is introduced into the polythiophene derivative due to the unintended oxidation reaction, it may cause problems in the production of the charge-transporting ink composition. It is known that polythiophene derivatives vary in solubility and dispersibility in organic solvents. One of the reasons for this is thought to be that the amount of quinoid structures introduced into the polythiophene due to the unintended oxidation reaction varies depending on the production conditions of each polythiophene derivative. Therefore, when the polythiophene derivative is subjected to a reduction treatment using a reducing agent, even if an excessive amount of quinoid structures has been introduced into the polythiophene derivative, the quinoid structures are reduced by the reduction, and the solubility and dispersibility of the polythiophene derivative in organic solvents are improved, making it possible to stably produce an excellent charge-transporting ink composition that gives a thin film with excellent homogeneity.

[0062] The conditions for the reduction treatment are not particularly limited as long as they can reduce the quinoid structure and appropriately convert it into a non-oxidized structure, i.e., the benzenoid structure (for example, in the case of a polythiophene derivative containing a repeating unit represented by formula (1) above, the quinoid structure represented by formula (1') above is converted into the structure represented by formula (1) above). For example, this treatment can be carried out by simply contacting the polythiophene derivative or the amine adduct with a reducing agent in the presence or absence of a suitable solvent. There are no particular limitations on the reducing agent as long as it can perform the reduction appropriately, but suitable examples include aqueous ammonia, hydrazine, and the like, which are readily available commercially. The amount of the reducing agent cannot be generally specified because it varies depending on the amount of reducing agent used. However, it is usually 0.1 parts by mass or more per 100 parts by mass of the polythiophene derivative or amine adduct to be treated in order to ensure appropriate reduction, and 10 parts by mass or less in order to prevent excess reducing agent from remaining.

[0063] In one example of a specific reduction method, the polythiophene derivative or amine adduct is stirred overnight in 28% aqueous ammonia at room temperature. Reduction under such relatively mild conditions sufficiently improves the solubility and dispersibility of the polythiophene derivative or amine adduct in organic solvents.

[0064] When an amine adduct of a polythiophene derivative is used in the charge transporting ink composition of the present invention, the reduction treatment may be carried out either before or after the formation of the amine adduct.

[0065] Note that this reduction treatment changes the solubility or dispersibility of the polythiophene derivative or its amine adduct in the solvent, and as a result, the polythiophene derivative or its amine adduct, which was not dissolved in the reaction system at the start of the treatment, may become dissolved by the completion of the treatment. In such cases, the polythiophene derivative or its amine adduct can be recovered by a method such as adding an organic solvent incompatible with the polythiophene derivative or its amine adduct (acetone, isopropyl alcohol, etc., in the case of sulfonated polythiophene) to the reaction system to cause a precipitate of the polythiophene derivative or its amine adduct, and then filtering the precipitate.

[0066] The weight-average molecular weight of the polythiophene derivative or its amine adduct containing a repeating unit represented by formula (1) is preferably about 1,000 to 1,000,000, more preferably about 5,000 to 100,000, and even more preferably about 10,000 to about 50,000. By setting the weight-average molecular weight at or above the lower limit, good conductivity can be obtained with good reproducibility, while by setting it at or below the upper limit, solubility in solvents can be improved. The weight-average molecular weight is a polystyrene-equivalent value determined by gel permeation chromatography.

[0067] The polythiophene derivative or amine adduct thereof contained in the charge transport ink composition of the present invention may be a single polythiophene derivative or amine adduct thereof containing a repeating unit represented by formula (1), or two or more types thereof. The polythiophene derivative containing the repeating unit represented by formula (1) may be a commercially available product or may be polymerized by a known method using a thiophene derivative or the like as a starting material, but in either case, it is preferable to use a product purified by a method such as reprecipitation or ion exchange. The use of a purified product can further improve the properties of an organic EL device having a thin film obtained from the charge transport ink composition of the present invention.

[0068] Sulfonation of conjugated polymers and sulfonated conjugated polymers (including sulfonated polythiophenes) are described in U.S. Patent No. 8,017,241 to Seshadri et al., and sulfonated polythiophenes are described in WO 2008 / 073149 and WO 2016 / 171935.

[0069] In the present invention, at least a portion of the polythiophene derivative or its amine adduct containing the repeating unit represented by formula (1) contained in the charge transporting ink composition is dissolved in an organic solvent.

[0070] In the present invention, as the charge transport substance, a polythiophene derivative containing a repeating unit represented by formula (1) or an amine adduct thereof may be used in combination with a charge transport substance consisting of another charge transport compound, but it is preferable that only a polythiophene derivative containing a repeating unit represented by formula (1) or an amine adduct thereof is used.

[0071] The content of the charge transporting substance in the charge transporting ink composition of the present invention is usually determined appropriately within the range of 0.05 to 40% by mass, preferably 0.1 to 35% by mass, of the solid content, taking into consideration the desired film thickness, the viscosity of the ink composition, and the like.

[0072] The charge transport ink composition of the present invention contains an organic solvent. Such an organic solvent is not particularly limited as long as it disperses or dissolves solids. Specific examples include aromatic or halogenated aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and chlorobenzene; aliphatic hydrocarbons such as n-heptane, n-hexane, and cyclohexane; ether solvents such as diethyl ether, tetrahydrofuran, dioxane, and 1,2-dimethoxyethane; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethyl acetate, n-hexyl acetate, ethyl lactate, γ-butyrolactone, and propylene. Ester solvents such as carbonate and diisopropyl malonate; halogenated hydrocarbon solvents such as methylene chloride, dichloromethane, 1,2-dichloroethane, and chloroform; amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone; alcohol solvents such as methanol, ethanol, isopropanol, n-propanol, cyclohexanol, diacetone alcohol, and 2-benzooxyethanol; ethylene glycol The solvent may be appropriately selected from glycol ether solvents such as 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, and propylene glycol monomethyl ether acetate; and glycol solvents 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, and 1,4-butanediol. In the present invention, among these, amide-based solvents, glycol ether-based solvents and glycol-based solvents are preferred, and 1,3-dimethyl-2-imidazolidinone, dipropylene glycol and dipropylene glycol monomethyl ether are more preferred. These organic solvents can be used either alone or in combination of two or more.

[0073] The charge transport ink composition of the present invention may contain water as a solvent, but from the viewpoint of reproducibly obtaining an organic EL device having excellent durability, the water content is preferably 10% by mass or less of the total solvent, more preferably 5% by mass or less, and it is optimal to use only an organic solvent as the solvent. Note that "only an organic solvent" in this case means that only an organic solvent is used as the solvent, and does not deny the presence of trace amounts of "water" contained in the organic solvent or solid content used.

[0074] The charge transport ink composition of the present invention may contain metal oxide nanoparticles. Nanoparticles refer to fine particles whose primary particles have an average particle size on the order of nanometers (typically 500 nm or less). Metal oxide nanoparticles refer to metal oxides formed into nanoparticles. The primary particle diameter of the metal oxide nanoparticles used in the present invention is not particularly limited as long as it is nano-sized, but in consideration of obtaining a thin film with good reproducibility and excellent flatness, it is preferably 2 to 150 nm, more preferably 3 to 100 nm, and even more preferably 5 to 50 nm. The particle diameter is measured using a nitrogen adsorption isotherm by the BET method.

[0075] The metals constituting the metal oxide nanoparticles used in the present invention include metals in the usual sense as well as semimetals. The metal in the ordinary sense is not particularly limited, but it is preferable to use one 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). On the other hand, a metalloid refers to an element whose chemical and / or physical properties are intermediate between those of a metal and a nonmetal. Although a universal definition of a metalloid has not been established, in the present invention, a total of six elements, namely, boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), and tellurium (Te), are defined as metalloids. These metalloids may be used alone or in combination with two or more of them, or may be used in combination with metals in the usual sense.

[0076] The metal oxide nanoparticles used in the present invention preferably contain oxides of one or more metals selected from 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). When two or more metals are used in combination, the metal oxide may be a mixture of oxides of individual metals or a composite oxide containing multiple metals.

[0077] Specific examples of metal oxides include B2O3, B2O, SiO2, SiO, GeO2, GeO, As2O4, As2O3, As2O5, Sb2O3, Sb2O5, TeO2, SnO2, ZrO2, Al2O3, and ZnO, with B2O3, B2O, SiO2, SiO, GeO2, GeO, As2O4, As2O3, As2O5, SnO2, SnO, Sb2O3, TeO2, and mixtures thereof being preferred, and SiO2 being more preferred.

[0078] The charge transport ink composition of the present invention may contain one type of metal oxide nanoparticles alone or two or more types.

[0079] The metal oxide nanoparticles contained in the charge transport ink composition of the present invention are preferably uniformly dispersed in the composition.

[0080] The metal oxide nanoparticles may contain one or more organic capping groups. The organic capping groups may be reactive or non-reactive. Examples of reactive organic capping groups include organic capping groups that can be crosslinked by ultraviolet light or a radical initiator.

[0081] In the charge transport ink composition of the present invention, the content of the metal oxide nanoparticles is not particularly limited, but from the viewpoint of suppressing particle aggregation in the charge transport ink composition and obtaining a thin film with excellent flatness and good reproducibility, the content is preferably 40 to 95 mass %, more preferably 50 to 95 mass %, and most preferably 60 to 90 mass %, of the solid content of the charge transport ink composition.

[0082] In particular, in the present invention, by using a metal oxide nanoparticle sol in which metal oxide nanoparticles are dispersed, a composition in which metal oxide nanoparticles are uniformly dispersed can be prepared with good reproducibility. In other words, rather than mixing and dispersing metal oxide nanoparticles themselves in a solvent together with a charge transporting substance, etc., a metal oxide nanoparticle sol is prepared in advance and then mixed with a mixture in which a charge transporting substance, etc. is dissolved or dispersed in a solvent, thereby enabling the reproducible production of a charge transporting ink composition in which metal oxide nanoparticles are uniformly dispersed. Such a metal oxide nanoparticle sol may be a commercially available product, or may be prepared by a known method using a solvent and metal oxide nanoparticles that may be contained in the charge transport ink composition of the present invention.

[0083] In particular, when preparing the charge transporting ink composition of the present invention, it is preferable to use a silica sol in which SiO2 nanoparticles are dispersed in a dispersion medium. The silica sol is not particularly limited, and can be appropriately selected from known silica sols. Commercially available silica sols are usually in the form of dispersions, such as SiO2 nanoparticles dispersed in various solvents, such as water, methanol, methyl ethyl ketone, methyl isobutyl ketone, N,N-dimethylacetamide, ethylene glycol, isopropanol, methanol, ethylene glycol monopropyl ether, cyclohexanone, ethyl acetate, toluene, and propylene glycol monomethyl ether acetate. In particular, in the present invention, silica sols in which the dispersion medium is an alcohol-based solvent, a glycol-based solvent, or water are preferred, and silica sols in which the dispersion medium is an alcohol-based solvent or a glycol-based solvent are more preferred. As the alcohol-based solvent or glycol-based solvent, water-soluble alcohols or glycol-based solvents are preferred, and methanol, 2-propanol, and ethylene glycol are more preferred.

[0084] Specific examples of commercially available silica sols include water-dispersed silica sols such as Snowtex (registered trademark) ST-O, ST-OS, ST-O-40, and ST-OL manufactured by Nissan Chemical Industries, Ltd., and Silicadol 20, 30, and 40 manufactured by Nippon Chemical Industries, Ltd.; and organosilica sols such as methanol silica sol, MA-ST-M, MA-ST-L, IPA-ST, IPA-ST-L, IPA-ST-ZL, and EG-ST manufactured by Nissan Chemical Industries, Ltd., but are not limited to these.

[0085] The concentration of SiO2 nanoparticles in silica sol is usually about 5 to 50 mass %. However, if the concentration of SiO2 nanoparticles is high, when the silica sol is mixed with a mixture in which a charge transporting substance or the like is dissolved or dispersed in a solvent, the SiO2 nanoparticles may aggregate depending on the type of solvent contained in the mixture; therefore, care must be taken when preparing the composition.

[0086] The charge transporting ink composition of the present invention contains an amine compound represented by formula (P1), a charge transporting substance, and an organic solvent, and may contain a dopant substance as needed to improve charge transportability, etc. The dopant substance is not particularly limited as long as it is dispersible or soluble in at least one solvent used in the charge transporting ink composition, and both inorganic and organic dopant substances can be used. When the charge transport ink composition of the present invention contains a dopant substance, the content thereof is appropriately set taking into consideration the type and amount of the charge transport substance, etc., but is usually in the range of 0.1 to 20.0 in mass ratio to 1 of the charge transport substance.

[0087] Inorganic dopant substances include inorganic acids such as hydrogen chloride, sulfuric acid, nitric acid, and phosphoric acid; metal halides such as aluminum chloride (III) (AlCl3), titanium tetrachloride (IV) (TiCl4), boron tribromide (BBr3), boron trifluoride etherate (BF3·OEt2), iron chloride (III) (FeCl3), copper (II) chloride (CuCl2), antimony pentachloride (V) (SbCl5), antimony pentafluoride (V) (SbF5), arsenic pentafluoride (V) (AsF5), phosphorus pentafluoride (PF5), and tris(4-bromophenyl)aluminum hexachloroantimonate (TBPAH); halogens such as Cl2, Br2, I2, ICl, ICl3, IBr, and IF4; and heteropolyacids such as phosphomolybdic acid and phosphotungstic acid.

[0088] In addition, organic dopant substances include tetracyanoquinodimethanes such as 7,7,8,8-tetracyanoquinodimethane (TCNQ) and 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane; tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), tetrachloro-7,7,8,8-tetracyanoquinodimethane, 2-fluoro-7,7,8,8-tetracyanoquinodimethane, 2-chloro-7,7,8,8-tetracyanoquinodimethane, 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane; Halotetracyanoquinodimethanes (haloTCNQs) such as quinodimethane and 2,5-dichloro-7,7,8,8-tetracyanoquinodimethane; benzoquinone derivatives such as tetrachloro-1,4-benzoquinone (chloranil) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ); benzenesulfonic acid, tosylic acid, p-styrenesulfonic acid, 2-naphthalenesulfonic acid, 4-hydroxybenzenesulfonic acid, 5-sulfosalicylic acid, p-dodecylbenzenesulfonic acid, dihexylbenzenesulfonic acid, 2,5-dihe xylbenzenesulfonic acid, dibutylnaphthalenesulfonic acid, 6,7-dibutyl-2-naphthalenesulfonic acid, dodecylnaphthalenesulfonic acid, 3-dodecyl-2-naphthalenesulfonic acid, hexylnaphthalenesulfonic acid, 4-hexyl-1-naphthalenesulfonic acid, octylnaphthalenesulfonic acid, 2-octyl-1-naphthalenesulfonic acid, hexylnaphthalenesulfonic acid, 7-hexyl-1-naphthalenesulfonic acid, 6-hexyl-2-naphthalenesulfonic acid, dinonylnaphthalenesulfonic acid, 2,7-dinonyl-4-naphthalenesulfonic acid Examples of the sulfonic acid include aryl sulfonic acid compounds such as phthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, 2,7-dinonyl-4,5-naphthalenedisulfonic acid, 1,4-benzodioxanedisulfonic acid derivatives described in WO 2005 / 000832, arylsulfonic acid derivatives described in WO 2006 / 025342, and dinonylnaphthalenesulfonic acid derivatives described in JP 2005-108828 A; aromatic sulfone compounds such as polystyrenesulfonic acid; and non-aromatic sulfone compounds such as 10-camphorsulfonic acid. These inorganic and organic dopant substances may be used alone or in combination of two or more.

[0089] Among these dopant substances, arylsulfonic acid compounds are preferred in the present invention, and preferred examples of the arylsulfonic acid compounds include arylsulfonic acid compounds represented by formula (H1) or (H2).

[0090] [ka]

[0091] A 1 represents O or S, with O being preferred. A 2 represents a naphthalene ring or an anthracene ring, with a naphthalene ring being preferred. A 3 represents a divalent to tetravalent perfluorobiphenyl group, and s represents A 1 and A 3 It is an integer that satisfies 2≦s≦4, but A 3 is a perfluorobiphenyldiyl group, preferably a perfluorobiphenyl-4,4'-diyl group, and s is preferably 2. q is A 2 represents the number of sulfonic acid groups bonded to q, and is an integer satisfying 1≦q≦4, with 2 being optimal.

[0092] A 4 ~A 8 are each independently a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group having 1 to 20 carbon atoms, or a halogenated alkenyl group having 2 to 20 carbon atoms, 4 ~A 8 At least three of the are halogen atoms.

[0093] Examples of halogenated alkyl groups having 1 to 20 carbon atoms include a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2,2-pentafluoroethyl group, a 3,3,3-trifluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, a 1,1,2,2,3,3,3-heptafluoropropyl group, a 4,4,4-trifluorobutyl group, a 3,3,4,4,4-pentafluorobutyl group, a 2,2,3,3,4,4,4-heptafluorobutyl group, and a 1,1,2,2,3,3,4,4,4-nonafluorobutyl group.

[0094] Examples of the halogenated alkenyl group having 2 to 20 carbon atoms include a perfluorovinyl group, a perfluoropropenyl group (allyl group), and a perfluorobutenyl group. Other examples of the halogen atom and the alkyl group having 1 to 20 carbon atoms include those similar to those mentioned above, but the halogen atom is preferably a fluorine atom.

[0095] Among these, A 4 ~A 8 is a hydrogen atom, a halogen atom, a cyano group, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, or a halogenated alkenyl group having 2 to 10 carbon atoms, and A 4 ~A 8 At least three of A are preferably fluorine atoms, and are selected from the group consisting of a hydrogen atom, a fluorine atom, a cyano group, an alkyl group having 1 to 5 carbon atoms, a fluorinated alkyl group having 1 to 5 carbon atoms, and a fluorinated alkenyl group having 2 to 5 carbon atoms, and 4 ~A 8 At least three of A are preferably fluorine atoms, and A is preferably a hydrogen atom, a fluorine atom, a cyano group, a perfluoroalkyl group having 1 to 5 carbon atoms, or a perfluoroalkenyl group having 1 to 5 carbon atoms. 4 , A 5 and A 8 It is even more preferred that is a fluorine atom. The perfluoroalkyl group is a group in which all hydrogen atoms of an alkyl group have been substituted with fluorine atoms, and the perfluoroalkenyl group is a group in which all hydrogen atoms of an alkenyl group have been substituted with fluorine atoms.

[0096] 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 most preferably 2.

[0097] When an organic compound is used as the dopant substance, the molecular weight thereof is preferably 3,000 or less, more preferably 2,500 or less, taking into consideration the solubility in organic solvents. In particular, the molecular weight of the arylsulfonic acid compound used as the dopant material is not particularly limited, but is preferably 2,000 or less, more preferably 1,500 or less, in consideration of solubility in organic solvents.

[0098] In the present invention, examples of arylsulfonic acid compounds that can be suitably used include, but are not limited to, the following compounds:

[0099] [ka]

[0100] The charge transport ink composition of the present invention may contain other amine compounds in addition to the amine compound represented by formula (P1) for the purpose of improving the dispersibility or solubility of the charge transport substance, such as a polythiophene derivative or an amine adduct thereof. Such other amine compounds are not particularly limited as long as they are soluble in at least one solvent used in the ink composition, and may be one type alone or two or more types.

[0101] Specific examples of primary amine compounds include methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, s-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, and n-hexadecylamine. Examples of monoalkylamine compounds include decylamine, n-heptadecylamine, n-octadecylamine, n-nonadecylamine, and n-eicosanylamine; and monoarylamine compounds such as aniline, tolylamine, 1-naphthylamine, 2-naphthylamine, 1-anthrylamine, 2-anthrylamine, 9-anthrylamine, 1-phenanthrylamine, 2-phenanthrylamine, 3-phenanthrylamine, 4-phenanthrylamine, and 9-phenanthrylamine.

[0102] Specific examples of the secondary amine compound include N-ethylmethylamine, N-methyl-n-propylamine, N-methylisopropylamine, N-methyl-n-butylamine, N-methyl-s-butylamine, N-methyl-t-butylamine, N-methylisobutylamine, diethylamine, N-ethyl-n-propylamine, N-ethylisopropylamine, N-ethyl-n-butylamine, N-ethyl-s-butylamine, N-ethyl-t-butylamine, dipropylamine, Nn-propylisopropylamine, Nn-propyl N-butylamine, Nn-propyl-s-butylamine, diisopropylamine, Nn-butylisopropylamine, Nt-butylisopropylamine, di(n-butyl)amine, di(s-butyl)amine, diisobutylamine, aziridine (ethyleneimine), 2-methylaziridine (propyleneimine), 2,2-dimethylaziridine, azetidine (trimethyleneimine), 2-methylazetidine, pyrrolidine, 2-methylpyrrolidine, 3-methylpyrrolidine, 2,5-dimethylpyrrolidine, piperidine, 2,6-di Dialkylamine compounds such as methylpiperidine, 3,5-dimethylpiperidine, 2,2,6,6-tetramethylpiperidine, hexamethyleneimine, heptamethyleneimine, and octamethyleneimine; diphenylamine, N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine, 1,1'-dinaphthylamine, 2,2'-dinaphthylamine, 1,2'-dinaphthylamine, carbazole, 7H-benzo[c]carbazole, 11H-benzo[a]carbazole, 7H-dibenzo[c,g]carbazole, 13H -dibenzo[a,i]carbazole and other diarylamine compounds; and alkylarylamine compounds such as N-methylaniline, N-ethylaniline, Nn-propylaniline, N-isopropylaniline, Nn-butylaniline, Ns-butylaniline, N-isobutylaniline, N-methyl-1-naphthylamine, N-ethyl-1-naphthylamine, Nn-propyl-1-naphthylamine, indoline, isoindoline, 1,2,3,4-tetrahydroquinoline, and 1,2,3,4-tetrahydroisoquinoline.

[0103] Specific examples of the tertiary amine compound include N,N-dimethylethylamine, N,N-dimethyl-n-propylamine, N,N-dimethylisopropylamine, N,N-dimethyl-n-butylamine, N,N-dimethyl-s-butylamine, N,N-dimethyl-t-butylamine, N,N-dimethylisobutylamine, N,N-diethylmethylamine, N-methyldi(n-propyl)amine, N-methyldiisopropylamine, N-methyldi(n-butyl)amine, N-methyldiisobutylamine, triethylamine, N,N-diethyl-n-butylamine, N,N-diisopropylethylamine, and N,N-di(n-butyl)ethylamine. trialkylamine compounds such as tri(n-propyl)amine, tri(i-propyl)amine, tri(n-butyl)amine, tri(i-butyl)amine, 1-methylacetidine, 1-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-propyl)aniline, N,N-di(i-propyl)aniline, and N,N-di(n-butyl)aniline.

[0104] In particular, when the charge transport ink composition of the present invention contains other amine compounds, the other amine compounds preferably contain primary amine compounds, and more preferably contain monoalkylamines, particularly monoalkylamines having from 2 to 20 carbon atoms, because these compounds have an excellent ability to improve the dispersibility and solubility of the charge transport substance, such as the polythiophene derivative or its amine adduct, used in the present invention.

[0105] When the charge transporting ink composition of the present invention contains other amine compounds, the content thereof is usually about 10 times or less by mass relative to the charge transporting substance such as the polythiophene derivative or its amine adduct used in the present invention.

[0106] Heteropolyacids can also be suitably used as dopant materials. Heteropolyacids are polyacids that have a structure in which a heteroatom is located at the center of the molecule, typically represented by a Keggin-type chemical structure shown in formula (A) or a Dawson-type chemical structure shown in formula (B), and are formed by condensing an isopolyacid, which is an oxyacid of vanadium (V), molybdenum (Mo), tungsten (W), or the like, with an oxyacid of a different element. Examples of such oxyacids of different elements include oxyacids of silicon (Si), phosphorus (P), and arsenic (As).

[0107] [ka]

[0108] Specific examples of heteropolyacids include phosphomolybdic acid, silicomolybdic acid, phosphotungstic acid, silicotungstic acid, phosphotungstomolybdic acid, etc. These may be used alone or in combination of two or more. The heteropolyacids used in the present invention are commercially available products, or can be synthesized by known methods. In particular, when only one type of heteropolyacid is contained, the one type of heteropolyacid preferably contains tungsten, i.e., phosphotungstic acid, silicotungstic acid, phosphotungstomolybdic acid, etc. are preferred, and phosphotungstic acid and silicotungstic acid are more preferred.

[0109] In addition, even if the heteropolyacid has a large or small number of elements in the structure represented by the general formula in a quantitative analysis such as elemental analysis, it can be used in the present invention as long as it is available as a commercially available product or is appropriately synthesized according to a known synthesis method. For example, phosphotungstic acid generally has the chemical formula H3(PW 12 O 40)·nH2O, but whether the number of P (phosphorus), O (oxygen), or W (tungsten) in this formula is large or small in quantitative analysis, it can be used in the present invention as long as it is commercially available or appropriately synthesized according to a known synthesis method. In this case, the mass of the heteropolyacid specified in the present invention does not refer to the mass of pure phosphotungstic acid (phosphotungstic acid content) in the synthesized or commercially available product, but rather refers to the total mass, including water of hydration and other impurities, in a form available as a commercially available product or in a form that can be isolated by a known synthesis method.

[0110] The charge transport ink composition of the present invention may contain a known organosilane compound. When a charge transport thin film obtained from the ink composition is used as a hole injection layer of an organic EL device, the inclusion of such an organosilane compound in the charge transport ink composition can improve the hole injection properties into a hole transport layer provided in contact with the charge transport thin film.

[0111] As the organic silane compound, alkoxysilane is preferred, and trialkoxysilane and tetraalkoxysilane are more preferred. Examples of the alkoxysilane include tetraethoxysilane, tetramethoxysilane, tetraisopropoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, dimethyldiethoxysilane, and dimethyldimethoxysilane. In the present invention, among these, tetraethoxysilane (TEOS), tetramethoxysilane, and tetraisopropoxysilane can be preferably used. These organic silane compounds can be used alone or in combination of two or more.

[0112] When the charge transport ink composition of the present invention contains an organosilane compound, the content thereof is typically about 0.1 to 50 mass % of the solid content. However, taking into consideration the balance between improving the flatness of the resulting thin film and suppressing a decrease in charge transport properties, the content is preferably about 0.5 to 40 mass %, more preferably about 0.8 to 30 mass %, and even more preferably about 1 to 20 mass %.

[0113] The viscosity of the charge transporting ink composition of the present invention is typically 1 to 50 mPa·s at 25° C., and the surface tension is typically 20 to 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 changing the types of organic solvents used, their ratios, solids concentration, etc., taking into consideration various factors such as the coating method used and the desired film thickness.

[0114] The solids concentration of the charge transport ink composition of the present invention is set appropriately taking into consideration the viscosity and surface tension of the charge transport ink composition, the thickness of the thin film to be produced, and the like, but is typically about 0.1 to 15% by mass. From the viewpoint of suppressing aggregation of the charge transport substance and metal oxide nanoparticles in the ink composition, the solids concentration is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 6% by mass or less.

[0115] When preparing the charge transport ink composition of the present invention, the amine compound represented by formula (P1), the charge transport material, the solvent, and, if necessary, the metal oxide nanoparticles and the dopant material can be mixed in any order, as long as the solids are uniformly dissolved or dispersed in the solvent. That is, for example, a method of dissolving the charge transport material and the amine compound represented by formula (P1) in a solvent to obtain a solution, and then dissolving the dopant material in the solution; a method of dissolving the dopant material in a solvent, and then dissolving the charge transport material and the amine compound represented by formula (P1) in the solution; or a method of mixing the amine compound represented by formula (P1), the charge transport material, and the dopant material, and then adding the mixture to a solvent to dissolve the mixture can all be used, as long as the solids are uniformly dissolved or dispersed in the solvent. When metal oxide nanoparticles are used, examples of the method include a method in which an aqueous dispersion or an organic solvent dispersion of the metal oxide nanoparticles is added at any timing in the above method, and a method in which a solution containing a pre-prepared amine compound represented by formula (P1) and a charge transporting substance, and other components or their solutions are added to an aqueous dispersion or an organic solvent dispersion of metal oxide nanoparticles. It should be noted that the charge transporting material and metal oxide nanoparticles may aggregate or precipitate when mixed together, depending on the type and amount of the solvent used. In preparing the charge transporting ink composition, heating may be performed as appropriate within a range that does not cause decomposition or deterioration of the components.

[0116] In the present invention, the charge transporting ink composition may be filtered using a sub-micrometer filter or the like during the production of the charge transporting ink composition or after all of the components have been mixed, in order to obtain a thin film with higher flatness with good reproducibility.

[0117] The charge transporting ink composition described above can be applied to a substrate and baked to form a charge transporting thin film on the substrate.

[0118] The method for applying the ink composition is not particularly limited, and examples thereof include a dipping method, a spin coating method, a transfer printing method, a roll coating method, a brush coating method, an inkjet method, a spray method, and a slit coating method. It is preferable to adjust the viscosity and surface tension of the ink composition depending on the application method.

[0119] Furthermore, when using the charge-transporting ink composition of the present invention, the baking atmosphere is not particularly limited; a thin film having a uniform film surface and high charge transport properties can be obtained not only in air but also in an inert gas atmosphere such as nitrogen or in a vacuum. The baking temperature is appropriately set within a range of approximately 100 to 260°C, taking into consideration the application of the resulting thin film, the level of charge transport properties to be imparted to the resulting thin film, the type and boiling point of the solvent, etc. However, when the resulting thin film is used as a hole injection layer of an organic EL device, a temperature of approximately 140 to 250°C is preferred, and approximately 145 to 240°C is more preferred. During baking, the temperature may be changed in two or more stages to achieve more uniform film formation or to promote the reaction on the substrate. Heating may be performed using an appropriate device, such as a hot plate or oven.

[0120] The thickness of the charge transporting thin film is not particularly limited, but is preferably 5 to 300 nm when used as a functional layer provided between an anode and a light-emitting layer, such as a hole injection layer, hole transport layer, or hole injection transport layer of an organic EL device. Methods for changing the film thickness include changing the solids concentration in the charge transporting ink composition and changing the amount of solution on the substrate during application.

[0121] The organic EL device of the present invention has a pair of electrodes and a charge transport layer made of the above-mentioned charge transport thin film of the present invention between the electrodes. Representative configurations of organic EL devices include, but are not limited to, the following (a) to (f). In the following configurations, an electron blocking layer or the like can be provided between the light-emitting layer and the anode, and a hole blocking layer or the like can be provided between the light-emitting layer and the cathode, as necessary. Furthermore, the hole injection layer, the hole transport layer, or the hole injection transport layer may also function as an electron blocking layer or the like, and the electron injection layer, the electron transport layer, or the electron injection transport layer may also function as a hole blocking layer or the like. Furthermore, an arbitrary functional layer can be provided between each layer as necessary. (a) Anode / hole injection layer / hole transport layer / light-emitting layer / electron transport layer / electron injection layer / cathode (b) Anode / hole injection layer / hole transport layer / light-emitting layer / electron injection transport layer / cathode (c) Anode / hole injection transport layer / light-emitting layer / electron transport layer / electron injection layer / cathode (d) Anode / hole injection transport layer / light-emitting layer / electron injection transport layer / cathode (e) Anode / hole injection layer / hole transport layer / light-emitting layer / cathode (f) Anode / hole injection transport layer / light-emitting layer / cathode

[0122] The terms "hole injection layer," "hole transport layer," and "hole injection transport layer" refer to layers formed between the light-emitting layer and the anode, which have the function of transporting holes from the anode to the light-emitting layer. When only one layer of a hole-transporting material is provided between the light-emitting layer and the anode, it is the "hole injection transport layer." When two or more layers of a hole-transporting material are provided between the light-emitting layer and the anode, the layer closest to the anode is the "hole injection layer," and the remaining layers are "hole transport layers." In particular, the hole injection (transport) layer is a thin film that is excellent not only in accepting holes from the anode but also in injecting holes into the hole transport (light-emitting) layer. The terms "electron injection layer," "electron transport layer," and "electron injection transport layer" refer to layers formed between the light-emitting layer and the cathode, which have the function of transporting electrons from the cathode to the light-emitting layer. When only one layer of an electron-transporting material is provided between the light-emitting layer and the cathode, it is the "electron injection transport layer." When two or more layers of electron-transporting materials are provided between the light-emitting layer and the cathode, the layer closest to the cathode is the "electron injection layer," and the other layers are "electron transport layers." The "light-emitting layer" is an organic layer that has a light-emitting function, and when a doping system is used, it contains a host material and a dopant material. In this case, the host material mainly functions to promote the recombination of electrons and holes and confine excitons within the light-emitting layer, while the dopant material functions to efficiently emit light from the excitons obtained by the recombination. In the case of a phosphorescent element, the host material mainly functions to confine excitons generated by the dopant within the light-emitting layer.

[0123] The charge transporting thin film prepared from the charge transporting ink composition of the present invention can be used as a functional layer formed between an anode and a light-emitting layer in an organic EL device, and is suitable as a hole injection layer, a hole transport layer, or a hole injection transport layer, more suitable as a hole injection layer or a hole transport layer, and even more suitable as a hole injection layer.

[0124] When an EL device is produced using the charge transporting ink composition of the present invention, the materials and production methods used include, but are not limited to, those listed below.

[0125] An example of a method for producing an OLED device having a hole injection layer made of a thin film obtained from the charge transport ink composition of the present invention is as follows: It is preferable to previously perform a surface treatment on the electrodes, such as cleaning with alcohol or pure water, or UV ozone treatment or oxygen plasma treatment, within a range that does not adversely affect the electrodes. A hole injection layer is formed on an anode substrate using the charge transport ink composition by the above method. The resulting substrate is introduced into a vacuum deposition apparatus, and a hole transport layer, a light-emitting layer, an electron transport layer / hole blocking layer, an electron injection layer, and a cathode metal are sequentially deposited. Alternatively, instead of forming the hole transport layer and the light-emitting layer by deposition in this method, these layers are formed by a wet process using a hole transport layer-forming composition containing a hole transport polymer and a light-emitting layer-forming composition containing a light-emitting polymer. If necessary, an electron blocking layer may be provided between the light-emitting layer and the hole transport layer.

[0126] Anode materials include transparent electrodes such as indium tin oxide (ITO) and indium zinc oxide (IZO), metal anodes made of metals such as aluminum, or alloys thereof, and preferably planarized anodes. Polythiophene derivatives and polyaniline derivatives with high charge transport properties can also be used. Other metals that may be used to form the metal anode include, but are not limited to, gold, silver, copper, indium, and alloys thereof.

[0127] Examples of materials for forming the hole transport layer include triarylamines such as (triphenylamine) dimer derivatives, [(triphenylamine) dimer] spiro dimer, N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)-benzidine (α-NPD), 4,4',4"-tris[3-methylphenyl(phenyl)amino]triphenylamine (m-MTDATA), and 4,4',4"-tris[1-naphthyl(phenyl)amino]triphenylamine (1-TNATA), and oligothiophenes such as 5,5"-bis-{4-[bis(4-methylphenyl)amino]phenyl}-2,2':5',2"-terthiophene (BMA-3T).

[0128] Materials for forming the light-emitting layer include, but are not limited to, low-molecular-weight light-emitting materials such as metal complexes such as aluminum complexes of 8-hydroxyquinoline, metal complexes of 10-hydroxybenzo[h]quinoline, bisstyrylbenzene derivatives, bisstyrylarylene derivatives, metal complexes of (2-hydroxyphenyl)benzothiazole, and silole derivatives; and systems in which a light-emitting material and an electron transfer material are mixed with a polymer compound such as poly(p-phenylenevinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], poly(3-alkylthiophene), or polyvinylcarbazole. Furthermore, when forming a light-emitting layer by vapor deposition, it may be co-deposited with a light-emitting dopant. Examples of the light-emitting dopant include, but are not limited to, metal complexes such as tris(2-phenylpyridine)iridium(III) (Ir(ppy)), naphthacene derivatives such as rubrene, quinacridone derivatives, and fused polycyclic aromatic rings such as perylene.

[0129] Examples of materials for forming the electron transport layer / hole blocking layer include, but are not limited to, oxydiazole derivatives, triazole derivatives, phenanthroline derivatives, phenylquinoxaline derivatives, benzimidazole derivatives, and pyrimidine derivatives.

[0130] Materials for forming the electron injection layer include, but are not limited to, metal oxides such as lithium oxide (LiO), magnesium oxide (MgO), and alumina (AlO), and metal fluorides such as lithium fluoride (LiF) and sodium fluoride (NaF). Cathode materials include, but are not limited to, aluminum, magnesium-silver alloy, aluminum-lithium alloy, and the like. Examples of materials for forming the electron blocking layer include, but are not limited to, tris(phenylpyrazole)iridium.

[0131] Hole-transporting polymers include poly[(9,9-dihexylfluorenyl-2,7-diyl)-co-(N,N'-bis{p-butylphenyl}-1,4-diaminophenylene)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(N,N'-bis{p-butylphenyl}-1,1'-biphenylene-4,4-diamine)], poly[(9,9-bis{1'-penten-5'-yl}fluorenyl-2,7-diyl)-co-(N,N'-bis{p-butylphenyl}-1,4-diaminophenylene)], and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine]-endcapped with Examples thereof include polysilcisquinoxane and poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)].

[0132] Examples of light-emitting polymers include polyfluorene derivatives such as poly(9,9-dialkylfluorene) (PDAF), polyphenylenevinylene derivatives such as poly(2-methoxy-5-(2'-ethylhexoxy)-1,4-phenylenevinylene) (MEH-PPV), polythiophene derivatives such as poly(3-alkylthiophene) (PAT), and polyvinylcarbazole (PVCz).

[0133] The materials constituting the anode, cathode and layers formed therebetween differ depending on whether an element having a bottom emission structure or a top emission structure is to be manufactured, and therefore, the materials are selected appropriately taking this into consideration. Typically, in bottom-emission elements, a transparent anode is used on the substrate side, and light is extracted from the substrate side, whereas in top-emission elements, a reflective anode made of metal is used, and light is extracted from the transparent electrode (cathode) side opposite the substrate. Therefore, in terms of anode materials, for example, transparent anodes such as ITO are used when manufacturing bottom-emission elements, and reflective anodes such as Al / Nd are used when manufacturing top-emission elements.

[0134] The organic EL device of the present invention may be sealed, if necessary, with a moisture scavenger or the like in accordance with a conventional method in order to prevent deterioration of the characteristics.

[0135] As described above, the charge transporting ink composition of the present invention is suitably used for forming a functional layer that is formed between the anode and light-emitting layer of an organic EL device. In addition, the charge transporting ink composition of the present invention can also be used for forming a charge transporting thin film in electronic devices such as organic photoelectric conversion devices, organic thin-film solar cells, organic perovskite photoelectric conversion devices, organic integrated circuits, organic field-effect transistors, organic thin-film transistors, organic light-emitting transistors, organic optical inspectors, organic photoreceptors, organic field quenching devices, light-emitting electrochemical cells, quantum dot light-emitting diodes, quantum lasers, organic laser diodes, and organic plasmon light-emitting devices.

[0136] The method of the present invention for improving the storage stability of a charge transport ink composition is a method for improving the storage stability of a charge transport ink composition containing an amine compound, a charge transport substance, and an organic solvent, in which the amine compound is an amine compound represented by formula (P1) above, and the preferred conditions for the solid contents of the amine compound, the charge transport substance, etc., and the type and amount of the organic solvent are the same as those described above. The improvement in the storage stability of the charge transport ink composition can be evaluated by the change in absorbance. Specifically, when the absorbance of the charge transport ink composition at the maximum absorption (for example, a wavelength of 620 nm) before exposure to the atmosphere is a(initial), the absorbance of the charge transport ink composition after 10 days of exposure is a(atmospheric exposure), and the difference in absorbance before and after exposure to the atmosphere (a(initial) - a(atmospheric exposure)) is Δa, the absolute value of the rate of change in 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 an even more preferred embodiment 7% or less, and in an even more preferred embodiment 6% or less.

[0137] The method of the present invention for improving the flatness of a charge-transporting thin film is a method for improving the flatness of a charge-transporting thin film obtained from a charge-transporting ink composition containing an amine compound, a charge-transporting substance, and an organic solvent, and the preferred conditions for the solid contents of the amine compound, the charge-transporting substance, etc., the type and amount of the organic solvent, and the conditions for forming the charge-transporting thin film are the same as those described above. The improvement in the flatness of the charge-transporting thin film can be evaluated by the average surface roughness Ra. Specifically, when the charge-transporting thin film formed on the substrate is measured using an atomic force microscope in a measurement area of ​​3 μm × 3 μm, the average surface roughness Ra (nm) is usually 2.80 nm or less, preferably 2.70 nm or less, more preferably 2.60 nm or less, and even more preferably 2.50 nm or less. In the present invention, the average surface roughness (Ra) of the charge transport thin film can be measured using, for example, an atomic force microscope Park-NX10 manufactured by Park Systems Corporation and an average surface roughness measuring cantilever OMCL-AC 160TS 10M manufactured by Olympus Corporation. [Example]

[0138] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. The apparatus used is as follows.

[0139] (1) Coating of charge transporting ink composition: Spin coater MS-A100, manufactured by Mikasa Co., Ltd. (2) Measurement of the average surface roughness (Ra) of the charge transport thin film: Atomic force microscope Park-NX10 manufactured by Park Systems and cantilever for measuring average surface roughness OMCL-AC 160TS 10M manufactured by Olympus Corporation (3) Measurement of the solution absorption spectrum of the ink composition: UV-3600 ultraviolet-visible-near-infrared spectrophotometer, manufactured by Shimadzu Science Co., Ltd. (4) Preparation of organic EL elements: Multi-function deposition system C-E2L1G1-N manufactured by Choshu Sangyo Co., Ltd. (5) Measurement of brightness of organic EL elements: Multi-channel IVL measurement device manufactured by EHC Co., Ltd.

[0140] [1] Synthesis of compounds [Manufacturing Example 1] An amine adduct of a polythiophene derivative, which is a polymer containing a repeating unit represented by formula (1a), was synthesized according to the methods described in U.S. Pat. No. 8,017,241 and WO 2016 / 171935.

[0141] [ka] (wherein a to d are the same as above.)

[0142] [Manufacturing Example 2] An arylsulfonic acid compound A represented by formula (b-1) was synthesized according to the method described in WO 2006 / 025342.

[0143] [ka]

[0144] [2] Preparation of solution and dispersion for preparing charge transport ink composition [Preparation Example 1] A 1,3-dimethyl-2-imidazolidinone solution containing 10 mass % of arylsulfonic acid compound A was prepared by stirring the solution at 400 rpm and 50° C. for 1 hour using a hot stirrer.

[0145] [Preparation Example 2] 100 g of ST-OS (Nissan Chemical Industries, Ltd.), a water-dispersed silica sol, and dipropylene glycol monomethyl ether (Kanto Chemical Industries, Ltd.; the same applies below) were placed in a recovery flask, and the water contained in ST-OS was replaced with dipropylene glycol monomethyl ether using an evaporator, yielding a silica sol (silica concentration 9.43% by mass) with dipropylene glycol monomethyl ether as the dispersion medium.

[0146] [3] Preparation of charge transport ink composition [Example 1-1] 3.24 g of 1,3-dimethyl-2-imidazolidinone, 5.17 g of dipropylene glycol (manufactured by Junsei Chemical Co., Ltd., the same applies hereinafter), and 3.55 g of dipropylene glycol monomethyl ether were placed in an Erlenmeyer flask and stirred at room temperature for 30 minutes using a stirrer. Then, 0.21 g of the 1,3-dimethyl-2-imidazolidinone solution of arylsulfonic acid compound A obtained in Preparation Example 1 was added, and the mixture was stirred at room temperature for 30 minutes using a stirrer. To the resulting mixture, 1.05 g of a solution obtained by stirring 0.10 g of the amine adduct of the polythiophene derivative obtained in Production Example 1, 4.75 g of 1,3-dimethyl-2-imidazolidinone (manufactured by Kanto Chemical Co., Ltd., the same applies hereinafter), and 0.15 g of 3-ethoxypropylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) at 80°C for 3 hours using a hot stirrer was added, and the mixture was stirred at room temperature for 30 minutes. Next, 1.78 g of the silica sol containing dipropylene glycol monomethyl ether as a dispersion medium obtained in Preparation Example 2 was added to the resulting mixture, and the mixture was stirred at room temperature for 30 minutes. Finally, the resulting mixture was filtered through a PP syringe filter with a pore size of 0.2 μm to obtain a charge transporting ink composition.

[0147] [Example 1-2] 3.24 g of 1,3-dimethyl-2-imidazolidinone, 5.17 g of dipropylene glycol, and 3.55 g of dipropylene glycol monomethyl ether were placed in an Erlenmeyer flask and stirred at room temperature for 30 minutes using a stirrer. Then, 0.21 g of the 1,3-dimethyl-2-imidazolidinone solution of arylsulfonic acid compound A obtained in Preparation Example 1 was added, and the mixture was stirred at room temperature for 30 minutes using a stirrer. To the resulting mixture, 1.05 g of a mixture obtained by stirring 0.10 g of the amine adduct of the polythiophene derivative obtained in Production Example 1, 4.75 g of 1,3-dimethyl-2-imidazolidinone, and 0.15 g of 3-isopropoxypropylamine (Tokyo Chemical Industry Co., Ltd.) using a hot stirrer at 80°C for 3 hours was added, and the mixture was stirred at room temperature for 30 minutes. Next, 1.78 g of the silica sol containing dipropylene glycol monomethyl ether as a dispersion medium obtained in Preparation Example 2 was added to the resulting mixture, and the mixture was stirred at room temperature for 30 minutes. Finally, the resulting mixture was filtered through a PP syringe filter with a pore size of 0.2 μm to obtain a charge transporting ink composition.

[0148] [Comparative Example 1-1] 3.24 g of 1,3-dimethyl-2-imidazolidinone, 5.17 g of dipropylene glycol, and 3.55 g of dipropylene glycol monomethyl ether were placed in an Erlenmeyer flask and stirred at room temperature for 30 minutes using a stirrer. Then, 0.21 g of the 1,3-dimethyl-2-imidazolidinone solution of arylsulfonic acid compound A obtained in Preparation Example 1 was added, and the mixture was stirred at room temperature for 30 minutes using a stirrer. To the resulting mixture, 1.05 g of a mixture obtained by stirring 0.10 g of the amine adduct of the polythiophene derivative obtained in Production Example 1, 4.75 g of 1,3-dimethyl-2-imidazolidinone, and 0.15 g of n-butylamine (Tokyo Chemical Industry Co., Ltd.) at 80°C for 3 hours using a hot stirrer was added, and the mixture was stirred at room temperature for 30 minutes. Next, 1.78 g of the silica sol containing dipropylene glycol monomethyl ether as a dispersion medium obtained in Preparation Example 2 was added to the resulting mixture, and the mixture was stirred at room temperature for 30 minutes. Finally, the resulting mixture was filtered through a PP syringe filter with a pore size of 0.2 μm to obtain a charge transporting ink composition.

[0149] [Comparative Example 1-2] 3.24 g of 1,3-dimethyl-2-imidazolidinone, 5.17 g of dipropylene glycol, and 3.55 g of dipropylene glycol monomethyl ether were placed in an Erlenmeyer flask and stirred at room temperature for 30 minutes using a stirrer. Then, 0.21 g of the 1,3-dimethyl-2-imidazolidinone solution of arylsulfonic acid compound A obtained in Preparation Example 1 was added, and the mixture was stirred at room temperature for 30 minutes using a stirrer. To the resulting mixture, 1.05 g of a mixture obtained by stirring 0.10 g of the amine adduct of the polythiophene derivative obtained in Production Example 1, 4.75 g of 1,3-dimethyl-2-imidazolidinone, and 0.15 g of isoamylamine (Tokyo Chemical Industry Co., Ltd.) at 80°C for 3 hours using a hot stirrer was added, and the mixture was stirred at room temperature for 30 minutes. Next, 1.78 g of the silica sol containing dipropylene glycol monomethyl ether as a dispersion medium obtained in Preparation Example 2 was added to the resulting mixture, and the mixture was stirred at room temperature for 30 minutes. Finally, the resulting mixture was filtered through a PP syringe filter with a pore size of 0.2 μm to obtain a charge transporting ink composition.

[0150] [Comparative Example 1-3] 0.10 g of the amine adduct of the polythiophene derivative obtained in Production Example 1 was added to 4.75 g of 1,3-dimethyl-2-imidazolidinone and 0.15 g of 3-aminopropanol (Tokyo Chemical Industry Co., Ltd.), and the mixture was stirred at 80°C for 3 hours using a hot stirrer. However, the amine adduct of the polythiophene derivative did not dissolve or disperse sufficiently, and a composition homogeneous enough to be used for forming a charge-transporting thin film could not be prepared.

[0151] [Comparative Example 1-4] 0.10 g of the amine adduct of the polythiophene derivative obtained in Production Example 1 was added to 4.75 g of 1,3-dimethyl-2-imidazolidinone and 0.15 g of 2-amino-1-methoxybutane (Tokyo Chemical Industry Co., Ltd.), and the mixture was stirred at 80°C for 3 hours using a hot stirrer. However, the amine adduct of the polythiophene derivative did not dissolve or disperse sufficiently, and a composition homogeneous enough to be used for forming a charge-transporting thin film could not be prepared.

[0152] [Comparative Example 1-5] 0.10 g of the amine adduct of the polythiophene derivative obtained in Production Example 1 was added to 4.75 g of 1,3-dimethyl-2-imidazolidinone and 0.15 g of bis(2-ethoxyethyl)amine (Tokyo Chemical Industry Co., Ltd.), and the mixture was stirred at 80°C for 3 hours using a hot stirrer. However, the amine adduct of the polythiophene derivative did not dissolve or disperse sufficiently, and a composition homogeneous enough to be used for forming a charge-transporting thin film could not be prepared.

[0153] [4] Preparation of charge transport thin films and evaluation of average surface roughness Ra [Example 2-1] The charge transporting ink composition obtained in Example 1-1 was applied to an ITO substrate using a spin coater, heated in air at 120°C for 1 minute, and then heated at 230°C for 15 minutes, to form a uniform thin film with a thickness of 30 nm on the ITO substrate. The ITO substrate used was a 25 mm x 25 mm x 0.7 mm glass substrate with indium tin oxide (ITO) patterned to a thickness of 50 nm on the glass substrate. Prior to use, impurities on the surface were removed using an O2 plasma cleaning device (150 W, 30 seconds).

[0154] [Example 2-2, Comparative Examples 2-1 and 2-2] 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 transporting ink composition obtained in Example 1-2 and Comparative Examples 1-1 and 1-2 were used instead of the charge transporting ink composition of Example 1-1.

[0155] The average surface roughness Ra of the charge-transporting thin films formed on the ITO substrates in Example 2-1, Example 2-2, Comparative Example 2-1, and Comparative Example 2-2 was evaluated using an atomic force microscope. The measurement range of the atomic force microscope was 3 μm × 3 μm. The results are shown in Table 1.

[0156] [Table 1]

[0157] As shown in Table 1, the average surface roughness of the thin film formed from the charge transport ink composition of the present invention was lower than that of the thin film formed from the charge transport ink composition of the comparative example. This is presumably because the use of the amine compound represented by formula (P1) contained in the charge transport ink composition of the present invention makes it possible to achieve a more stable interaction between the amine compound and the charge transport substance, thereby mitigating or suppressing aggregation of the charge transport substance during the heating step after application of the composition.

[0158] [5] Evaluation of the stability of charge transport ink composition against atmospheric exposure [Example 3-1] 0.2 g of the charge transporting ink composition obtained in Example 1-1 was mixed with 4.14 g of 1,3-dimethyl-2-imidazolidinone, 4.83 g of dipropylene glycol, and 4.83 g of dipropylene glycol monomethyl ether, and the absorption spectrum of the resulting mixture was measured. Next, 3.0 g of the charge-transporting ink composition obtained in Example 1-1 was added to a 20 mL glass vial and exposed to the atmosphere at room temperature for 10 days with the lid of the vial open. 0.2 g of the exposed charge-transporting ink composition was mixed with 4.14 g of 1,3-dimethyl-2-imidazolidinone, 4.83 g of dipropylene glycol, and 4.83 g of dipropylene glycol monomethyl ether, and the absorption spectrum of the resulting mixture was measured. The absorption spectrum was measured using a quartz cell with an optical path length of 1 cm.

[0159] [Example 3-2, Comparative Examples 3-1 to 3-2] The absorption spectrum was measured in the same manner as in Example 3-1, except that the charge transporting ink compositions obtained in Example 1-2 and Comparative Examples 1-1 and 1-2 were used instead of the charge transporting ink composition obtained in Example 1-1.

[0160] The measured absorption spectrum is shown in Figure 1. Table 2 also shows the absorbance (a(initial)) of the charge-transporting ink composition before exposure to the atmosphere, the absorbance (a(exposed to the atmosphere)) of the charge-transporting ink composition after 10 days of exposure, the difference in absorbance before and after exposure to the atmosphere (Δa), and the rate of change in absorbance (%) at the wavelength of 620 nm where the absorption is maximum.

[0161] [Table 2]

[0162] As shown in Figure 1 and Table 2, the change in absorbance of the charge transport ink composition of the present invention was smaller than that of the charge transport ink composition of the comparative example. This is presumably because the use of the amine compound represented by formula (P1) contained in the charge transport ink composition of the present invention makes it possible to achieve stable interaction between the amine compound and the charge transport substance in the composition, thereby suppressing oxidation of the charge transport substance.

[0163] [6] Fabrication and characterization of organic EL devices [Example 4-1] The charge-transporting ink composition obtained in Example 1-1 was applied to an ITO substrate using a spin coater, heated in air at 120°C for 1 minute, and then heated at 230°C for 15 minutes, to form a uniform charge-transporting thin film with a thickness of 30 nm on the ITO substrate. The ITO substrate used was a 25 mm × 25 mm × 0.7 mm glass substrate with a patterned ITO film of 150 nm formed on its surface. Before use, impurities on the surface were removed using an O2 plasma cleaning device (150 W, 30 seconds). Next, a vapor deposition apparatus (vacuum degree 1.0×10) was used to deposit the charge transport thin film formed on the ITO substrate. -5 Using a 30 nm thick film of α-NPD (N,N'-di(1-naphthyl)-N,N'-diphenylbenzidine) at a rate of 0.2 nm / sec, a 30 nm thick film was formed. A 10-nm thick film of electron blocking material HTEB-01 (Kanto Chemical Co., Ltd.) was deposited on the α-NPD film, and then the emissive layer host material NS60 (Nippon Steel & Sumikin Chemical Co., Ltd.) and the emissive layer dopant material Ir(ppy)3 were co-deposited on top of the α-NPD film. The deposition rate was controlled to achieve a 6% Ir(ppy)3 concentration, resulting in a 40-nm thick film. Next, thin films of Alq3, lithium fluoride, and aluminum were sequentially deposited to obtain an organic EL device. The deposition rates were 0.2 nm / sec for Alq3 and aluminum, and 0.02 nm / sec for lithium fluoride, resulting in film thicknesses of 20 nm, 0.5 nm, and 80 nm, respectively.

[0164] To prevent deterioration of characteristics due to the influence of oxygen, water, etc. in the air, the organic EL elements were sealed with sealing substrates before their characteristics were evaluated. Sealing was performed as follows: In a nitrogen atmosphere with an oxygen concentration of 2 ppm or less and a dew point of -76°C or less, the organic EL elements were placed between sealing substrates, and the sealing substrates were bonded together with an adhesive (MORESCO Moisture Cut WB90US(P), manufactured by MORESCO Corporation). At this time, a moisture scavenger (HD-071010W-40, manufactured by DYNIC Corporation) was placed inside the sealing substrate together with the organic EL elements. The bonded sealing substrates were irradiated with UV light (wavelength: 365 nm, irradiation dose: 6,000 mJ / cm). 2 ), and then annealed at 80°C for 1 hour to cure the adhesive.

[0165] [Example 4-2] An organic EL device was obtained in the same manner as in Example 4-1, except that the charge transporting ink composition obtained in Example 1-2 was used instead of the charge transporting ink composition obtained in Example 1-1.

[0166] The elements obtained in Examples 4-1 and 4-2 were each measured at a luminance of 10,000 cd / m2 The driving voltage, current density, luminous efficiency, and brightness half-life (initial brightness 10,000 cd / m) 2 The time required for the volume to reach half of its original volume was measured. The results are shown in Table 3.

[0167] [Table 3]

[0168] The organic EL devices obtained in Examples 4-1 and 4-2 both exhibited good device characteristics.

Claims

1. A charge transporting ink composition comprising an amine compound represented by the following formula (P1), a charge transporting substance, and an organic solvent: 【Chemical 1】 (In the formula, R m represents an alkyl group selected from the group consisting of a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, and an n-nonyl group; an alkenyl group selected from the group consisting of an ethenyl group, an n-1-propenyl group, an n-2-propenyl group, a 1-methylethenyl group, an n-1-butenyl group, an n-2-butenyl group, an n-3-butenyl group, a 2-methyl-1-propenyl group, a 2-methyl-2-propenyl group, a 1-ethylethenyl group, a 1-methyl-1-propenyl group, a 1-methyl-2-propenyl group, and an n-1-pentenyl group; or an aryl group selected from the group consisting of a phenyl group and a tolyl group, n represents any alkylene group selected from the group consisting of a methylene group, an ethylene group, a propylene group, a trimethylene group, a tetramethylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, and a nonylene group; any alkenylene group selected from the group consisting of a vinylene group, a propenylene group, a butenylene group, a pentenylene group, a hexenylene group, a heptenylene group, an octenylene group, and a nonenylene group; or a phenylene group, or R m and R n The alkylene groups having 1 to 5 carbon atoms are bonded to each other to form an alkanetriyl group having 3 to 10 carbon atoms, and R n The alkylene group and the alkenylene group and R m and R n The alkanetriyl group in formula (P1) is —NH 2 When bonded to -CH 2 -NH 2 However, this does not include cases where the total number of carbon atoms in R m and R n is 11 or more.)

2. The above R m is any alkyl group selected from the group consisting of a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, and an n-nonyl group, and n 2. The charge transporting ink composition according to claim 1, wherein is an alkylene group selected from the group consisting of methylene, ethylene, propylene, trimethylene, tetramethylene, pentylene, hexylene, heptylene, octylene and nonylene.

3. 3. The charge transporting ink composition according to claim 1, wherein the charge transporting substance is a polythiophene derivative containing a repeating unit represented by the following formula (1) or an amine adduct thereof: 【Chemistry 2】 (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 are bonded to each other, Y is an alkylene group having 1 to 40 carbon atoms which may contain an ether bond and which may be substituted with a sulfonic acid group, Z is an alkylene group having 1 to 40 carbon atoms which may be substituted with a halogen atom, p is an integer of 1 or more, and 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.

4. The above R 1 is a sulfonic acid group, and the R 2 is an alkoxy group having 1 to 40 carbon atoms or —O—[Z—O] p -R e or the above R 1 and R 2 4. The charge transporting ink composition according to claim 3, wherein the bond is --O--Y--O--.

5. 5. The charge transporting ink composition according to claim 1, further comprising a dopant substance.

6. 6. The charge transporting ink composition according to claim 5, wherein the dopant substance comprises at least one selected from the group consisting of arylsulfonic acid compounds and heteropolyacid compounds.

7. 7. The charge transporting ink composition according to claim 1, further comprising metal oxide nanoparticles.

8. A charge transporting thin film obtained from the charge transporting ink composition according to any one of claims 1 to 7.

9. An electronic device comprising the charge transporting thin film according to claim 8.

10. The electronic device according to claim 9, wherein the charge transporting thin film is a hole injection layer, a hole transport layer, or a hole injection transport layer.

11. 10. The electronic device according to claim 9, which is an organic electroluminescence device.

12. A method for improving the storage stability of a charge transporting ink composition containing an amine compound, a charge transporting substance, and an organic solvent, comprising: A method for improving the storage stability of a charge transporting ink composition, comprising using an amine compound represented by the following formula (P1) as the amine compound: 【Chemistry 3】 (In the formula, R m represents an alkyl group selected from the group consisting of a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, and an n-nonyl group; an alkenyl group selected from the group consisting of an ethenyl group, an n-1-propenyl group, an n-2-propenyl group, a 1-methylethenyl group, an n-1-butenyl group, an n-2-butenyl group, an n-3-butenyl group, a 2-methyl-1-propenyl group, a 2-methyl-2-propenyl group, a 1-ethylethenyl group, a 1-methyl-1-propenyl group, a 1-methyl-2-propenyl group, and an n-1-pentenyl group; or an aryl group selected from the group consisting of a phenyl group and a tolyl group, n represents any alkylene group selected from the group consisting of a methylene group, an ethylene group, a propylene group, a trimethylene group, a tetramethylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, and a nonylene group; any alkenylene group selected from the group consisting of a vinylene group, a propenylene group, a butenylene group, a pentenylene group, a hexenylene group, a heptenylene group, an octenylene group, and a nonenylene group; or a phenylene group; m and R n The alkylene groups having 1 to 5 carbon atoms are bonded to each other to form an alkanetriyl group having 3 to 10 carbon atoms, and R n The alkylene group and the alkenylene group and R m and R n The alkanetriyl group in formula (P1) is —NH 2 When bonded to -CH 2 -NH 2 However, this does not include cases where the total number of carbon atoms in R m and R n is 11 or more.)

13. A method for improving the flatness of a charge-transporting thin film obtained from a charge-transporting ink composition containing an amine compound, a charge-transporting substance, and an organic solvent, comprising: A method for improving the flatness of a charge-transporting thin film, characterized in that an amine compound represented by the following formula (P1) is used as the amine compound: 【Chemistry 4】 (In the formula, R m represents an alkyl group selected from the group consisting of a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, and an n-nonyl group; an alkenyl group selected from the group consisting of an ethenyl group, an n-1-propenyl group, an n-2-propenyl group, a 1-methylethenyl group, an n-1-butenyl group, an n-2-butenyl group, an n-3-butenyl group, a 2-methyl-1-propenyl group, a 2-methyl-2-propenyl group, a 1-ethylethenyl group, a 1-methyl-1-propenyl group, a 1-methyl-2-propenyl group, and an n-1-pentenyl group; or an aryl group selected from the group consisting of a phenyl group and a tolyl group, n represents any alkylene group selected from the group consisting of a methylene group, an ethylene group, a propylene group, a trimethylene group, a tetramethylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, and a nonylene group; any alkenylene group selected from the group consisting of a vinylene group, a propenylene group, a butenylene group, a pentenylene group, a hexenylene group, a heptenylene group, an octenylene group, and a nonenylene group; or a phenylene group, or R m and R n The alkylene groups having 1 to 5 carbon atoms are bonded to each other to form an alkanetriyl group having 3 to 10 carbon atoms, and R n The alkylene group and the alkenylene group and R m and R n The alkanetriyl group in formula (P1) is —NH 2 When bonded to -CH 2 -NH 2 However, this does not include cases where the total number of carbon atoms in R m and R n is 11 or more.)

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