Charge transport composition

Abstract

As a charge transport composition which is suitable for the formation of a charge transport thin film of a photoelectric conversion element, and in particular, which is capable of significantly improving the photoelectric conversion efficiency of an obtained element when used as a hole collecting layer of an inverse lamination type perovskite solar cell, the present invention provides a charge transport composition for forming a charge transport thin film of an organic photoelectric conversion element, the composition comprising a charge transport substance, a crosslinking agent, and an organic solvent. The charge transport substance comprises at least one polyimide-based polymer which is selected from the group consisting of polyimide precursors that are each obtained from a tetracarboxylic acid component and a diamine component having any one of the structures represented by formulae (1)-(3), esters of the polyimide precursors, and imidized products of the polyimide precursors. (In the formulae, R1 represents a hydrogen atom or a monovalent organic group. * represents a site bonded to another group. Any hydrogen atom forming the benzene ring may be substituted with a monovalent organic group.)

Description

Charge transporting composition

[0001] The present invention relates to a charge transporting composition, and more specifically to a charge transporting composition for forming a charge transporting thin film used in an organic photoelectric conversion element.

[0002] Electronic elements, particularly organic photoelectric conversion elements, are devices that convert light energy into electrical energy using organic semiconductors, such as organic solar cells. Organic solar cells are solar cell elements that use organic materials in the active layer and charge transport material, and well-known examples include the dye-sensitized solar cell developed by M. Graetzel and the organic thin-film solar cell developed by C. W. Tang (Non-Patent Documents 1 and 2). Both have advantages that distinguish them from currently mainstream inorganic solar cells, such as being lightweight, thin, flexible, and capable of roll-to-roll production, and are therefore expected to create new markets.

[0003] On the other hand, in recent years, research results have been reported that solar cells using metal halides as compounds having a perovskite crystal structure (hereinafter referred to as "perovskite semiconductor compounds") can achieve relatively high photoelectric conversion efficiencies, and these have attracted attention. For example, Patent Document 1 describes a photoelectric conversion element and a solar cell having an active layer containing a perovskite semiconductor compound.

[0004] In photoelectric conversion elements that use perovskite semiconductor compounds in their active layers, further investigations are being conducted into the conditions of not only the active layer but also other layers that are combined with it, in order to further improve the element characteristics.

[0005] Japanese Patent Application Laid-Open No. 2016-178193

[0006] Nature, vol.353, 737-740 (1991)Appl. Phys. Lett., Vol.48, 183-185 (1986)

[0007] The present invention has been made in view of the above circumstances, and has an object to provide a charge-transporting composition that is suitable for forming a charge-transporting thin film for a photoelectric conversion element, and in particular, when used as a hole-collection layer in an inverted stacking type perovskite solar cell, can significantly improve the photoelectric conversion efficiency (PCE) of the resulting element.

[0008]

[0006] As a result of extensive research to achieve the above object, the present inventors have found that a charge transport composition comprising a charge transport material, a crosslinker, and an organic solvent, the charge transport material being a polyimide polymer obtained by using a diamine component having a specific structure, is suitable for forming a charge transport thin film in an organic photoelectric conversion element. In particular, they have found that when the charge transport thin film is used as a hole collection layer in an inverted stack type perovskite solar cell, the charge transport thin film exhibits excellent solvent resistance to the composition for the perovskite layer formed thereon, and can significantly improve the PCE of the resulting element, thereby completing the present invention.

[0009] That is, the present invention provides the following charge transport composition: 1. A charge transport composition for forming a charge transport thin film in an organic photoelectric conversion element, comprising a charge transport substance, a crosslinking agent, and an organic solvent, wherein the charge transport substance comprises at least one polyimide polymer selected from the group consisting of a polyimide precursor obtained from a diamine component having a structure represented by any one of the following formulas (1) to (3) and a tetracarboxylic acid component, an ester of the polyimide precursor, and an imidized product of the polyimide precursor: (In the formula, R 1 represents a hydrogen atom or a monovalent organic group. * represents a site bonding to another group. Any hydrogen atom forming a benzene ring may be substituted with a monovalent organic group. 2. The charge transport composition of 1, wherein the crosslinking agent is at least one compound selected from the group consisting of partial structures represented by the following formulas (b1) to (b2): a compound having two or more epoxy groups, a compound having two or more oxetane rings, and a compound having two or more oxazoline rings. [In formula (b1), R b1 and Rb1' are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or *b4-CH2-O-R b11 represents R b11 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and *b4 represents R b1 and R b1' represents a bond to the carbon atom to which it is bonded, and R b2 and R b2' each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, n1 represents 0 or 1, and *b1 and *b2 represent a bond. b represents an (n2+n3+1)-valent aromatic ring, R b3 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and when n3 is 0, R b3 At least one of represents a hydrogen atom, n2 represents an integer of 1 to 6, n3 represents an integer of 0 to 6, and *b3 represents a bond.] 3. The crosslinking agent is a compound represented by the following formulas (B1-1), (B1-2), (B1-3), (B2-1) and (B E 2. The charge transport composition of 2, which is at least one selected from the group consisting of: [In formula (B1-1), A b represents an organic group having a valence of nx; R b4 each independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a partial structure represented by the following formula (b1-1), nx represents an integer of 2 to 6, R b1 、 R b2 、 R b1’ and R b2’ In formulas (B1-2) and (B1-3), R b5 and R b6 each independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a partial structure represented by the following formula (b1-1), or a partial structure represented by the following formula (b1-2), and a plurality of R b5 At least two of R represent a partial structure represented by the following formula (b1-1) or a partial structure represented by the following formula (b1-2), b6 At least two of the following represent a partial structure represented by formula (b1-1):b3 , n2 and n3 have the same meaning as above, and when at least one of n2 is 0, R b3 At least one of represents a hydrogen atom, and Y b represents an aromatic ring, any hydrogen atom of which may be substituted with an alkyl group having 1 to 3 carbon atoms, a halogen atom, an alkoxy group having 1 to 3 carbon atoms, or a vinyl group; Z b represents a single bond, a saturated hydrocarbon group having 1 to 10 carbon atoms, -NR Z -or-P 1 -Q 1 -P 2 -, and the R Z represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and 1 and P 2 each independently represents an alkyl group having 1 to 5 carbon atoms, and 1 represents an aromatic ring, the saturated hydrocarbon groups may be bonded together in whole or in part to form a cyclic structure, any hydrogen atom may be substituted with a fluorine atom, and ny represents an integer of 2 to 6. E ) Medium, R E is a divalent organic group having an aromatic ring or a cyclohexane ring and having 6 to 40 carbon atoms, provided that the group R E It may contain an oxygen atom or a sulfur atom. (In the formula, R b1 , R b1’ , R b2 , R b2’ , n1 have the same meaning as above, R b7 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, n4 represents an integer of 1 to 6, and * represents a bond. 4. The charge transport composition of 3, wherein the crosslinking agent is at least one selected from the group consisting of the following formulas (1) to (7): 5. The charge transporting composition according to any one of 1 to 4, wherein the content of the crosslinking agent is 0.01 to 1.0 in terms of mass ratio relative to the charge transporting substance. 1is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a fluoroalkyl group having 1 to 5 carbon atoms, or a tert-butoxycarbonyl group. 7. A charge transport composition of any of 1 to 6, which is for use in a hole collection layer of a perovskite photoelectric conversion element. 8. A charge transport thin film obtained from the charge transport composition of any of 1 to 6. 9. The charge transport thin film of 8, which is a hole collection layer of a perovskite photoelectric conversion element. 10. A perovskite photoelectric conversion element comprising the charge transport thin film of 9. 11. The perovskite photoelectric conversion element of 10, which is of an inverted stack type. 12. A solar cell comprising the perovskite photoelectric conversion element of 10. 13. A method for producing a charge transport thin film for an organic photoelectric conversion element, which comprises applying the charge transport composition of any of 1 to 7 onto an active layer or an anode, and baking the applied composition.

[0010] The charge-transporting composition of the present invention is suitable for forming a charge-transporting thin film for a photoelectric conversion element. In particular, when the charge-transporting thin film is used as a hole-collecting layer for an inverted stack type perovskite photoelectric conversion element, the charge-transporting thin film exhibits excellent solvent resistance to the composition for the perovskite layer, and a perovskite photoelectric conversion element having a high PCE can be obtained.

[0011] The present invention will be described in more detail below. The charge-transporting composition of the present invention is a charge-transporting composition for forming a charge-transporting thin film in an organic photoelectric conversion element, and is characterized in that it comprises a charge-transporting substance, a crosslinking agent, and an organic solvent, and the charge-transporting substance comprises at least one polyimide-based polymer selected from the group consisting of a polyimide precursor obtained from a diamine component having a structure represented by any one of formulas (1) to (3) below and a tetracarboxylic acid component, an ester of the polyimide precursor, and an imidized product of the polyimide precursor. The polyimide-based polymer generally has high heat resistance and excellent mechanical properties and is widely used in the field of electronic devices. Furthermore, the polyimide-based polymer is easily mass-producible and is suitable as a material for forming a charge-transporting thin film in an organic photoelectric conversion element, particularly a perovskite solar cell.

[0012] [Charge-Transporting Substance] <Polyimide-Based Polymer> The charge-transporting composition of the present invention contains, as a charge-transporting substance, at least one polyimide-based polymer selected from the group consisting of a polyimide precursor obtained from a diamine component having a structure represented by any one of the following formulas (1) to (3) and a tetracarboxylic acid component, an ester of the polyimide precursor, and an imidized product of the polyimide precursor:

[0013] (In the formula, R 1 represents a hydrogen atom or a monovalent organic group. * represents a bonding site to another group. Any hydrogen atom forming a benzene ring may be substituted with a monovalent organic group.

[0014] Hereinafter, the diamines having the structures of formulas (1) to (3) may be referred to as "specific diamines." Furthermore, the polymers containing the specific diamines of the present invention may be referred to as "specific polymers."

[0015] <Specific Diamine> The specific diamine has any of the structures represented by the following formulas (1) to (3).

[0016]

[0017] In the above formulas (1) to (3), R 1 represents a hydrogen atom or a monovalent organic group. * represents a site bonding to another group. Any hydrogen atom forming the benzene ring may be substituted with a monovalent organic group. Examples of the monovalent organic group include an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a fluoroalkyl group having 1 to 10 carbon atoms, a fluoroalkenyl group having 2 to 10 carbon atoms, a fluoroalkoxy group having 1 to 10 carbon atoms, a tert-butoxycarbonyl group, and an aromatic hydrocarbon group in which a hydrogen atom may be substituted with a halogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms.

[0018] Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an i-butyl 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, and an n-decyl group.

[0019] Examples of alkenyl groups having 2 to 10 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, and n-1-decenyl.

[0020] Examples of the alkoxy group having 1 to 10 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, an i-butoxy group, an s-butoxy group, a t-butoxy group, an n-pentoxy group, an n-hexyloxy group, an n-heptyloxy group, an n-octyloxy group, an n-nonyloxy group, and an n-decyloxy group.

[0021] The fluoroalkyl group having 1 to 10 carbon atoms is not particularly limited as long as it is an alkyl group having 1 to 10 carbon atoms in which at least one hydrogen atom on a carbon atom has been 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, and 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, Examples thereof include a 2,3,3,3-tetrafluoropropyl group, a 1,1,2,2,3-pentafluoropropyl group, a 1,2,2,3,3-pentafluoropropyl group, a 1,1,3,3,3-pentafluoropropyl group, a 1,2,3,3,3-pentafluoropropyl group, a 2,2,3,3,3-pentafluoropropyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, a perfluoroheptyl group, and a perfluorooctyl group.

[0022] The fluoroalkenyl group having 2 to 10 carbon atoms is not particularly limited as long as it is a fluoroalkenyl group having 2 to 10 carbon atoms in which at least one hydrogen atom on a carbon atom has been substituted with a fluorine atom, and specific examples thereof include a 2-fluoroethenyl group, a 2,2-difluoroethenyl group, a 2-fluoro-2-propenyl group, a 3,3-difluoro-2-propenyl group, a 2,3-difluoro-2-propenyl group, a 3,3-difluoro-2-methyl-2-propenyl group, a 3-fluoro-2-butenyl group, a perfluorovinyl group, a perfluoropropenyl group, and a perfluorobutenyl group.

[0023] The fluoroalkoxy group having 1 to 10 carbon atoms is not particularly limited as long as it is an alkoxy group having 1 to 10 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. , a 1,2,2-trifluoroethoxy group, a 2,2,2-trifluoroethoxy group, a 1,1,2,2-tetrafluoroethoxy group, a 1,2,2,2-tetrafluoroethoxy group, a perfluoroethoxy group, a 1-fluoropropoxy group, a 2-fluoropropoxy group, a 3-fluoropropoxy group, a 1,1-difluoropropoxy group, a 1,2-difluoropropoxy group, a 1,3-difluoropropoxy group, a 2,2-difluoropropoxy group, a 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 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.

[0024] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being preferred.

[0025] Examples of aromatic hydrocarbon groups include monovalent groups derived from a 5- or 6-membered monocyclic ring or 2- to 5-fused rings. Specific examples include monovalent groups derived from a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzpyrene ring, a chrysene ring, a triphenylene ring, an acenaphthene ring, and a fluorene ring. More specific examples 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. Phenyl and tolyl groups are preferred, and a phenyl group is more preferred.

[0026] The above R 1 As the alkyl group, a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluoroalkyl group having 1 to 3 carbon atoms, a fluoroalkenyl group having 2 to 3 carbon atoms, a fluoroalkoxy group having 1 to 3 carbon atoms, and a tert-butoxycarbonyl group are preferred, a hydrogen atom and an alkyl group having 1 to 3 carbon atoms are more preferred, and a hydrogen atom and a methyl group are even more preferred.

[0027] In the structure of the above formula (1), the bonding position of the benzene ring to the pyrrole ring is preferably the carbon atom next to the nitrogen atom on the pyrrole ring as shown in the following formula (1-1), from the viewpoint of charge transport properties.

[0028]

[0029] Preferred examples of the diamine having the structure of the above formula (1) include diamines represented by the following formula (1-2).

[0030]

[0031] In the above formula (1-2), R 1 is the same as in formula (1). 2 are each independently a single bond or a structure of the following formula (1-3): As in the case of formula (1), any hydrogen atom forming the benzene ring may be substituted with a monovalent organic group.

[0032]

[0033] In formula (1-3), R 3 represents a single bond, -O-, -COO-, -OCO-, -(CH2) i -, -O(CH2) j O-, -CONH-, -NHCO-, -CON(CH3)-, -N(CH3)CO-, and -NR 1 - represents a divalent organic group selected from the group consisting of, where i represents an integer of 1 to 14, and j represents an integer of 1 to 14. R 1 is the same as in the case of formula (1). Among these, from the viewpoint of charge transportability, R 3 is preferably a single bond, -O-, -COO-, -OCO-, -CONH-, -NHCO-, or -N(CH3)-. *1 represents the site of bonding to the benzene ring in formula (2). *2 represents the site of bonding to the amino group in formula (1-2). k1 in formula (1-2) is an integer of 1 to 3, preferably 1 or 2.

[0034] Specific examples of the above formula (1-2) include, but are not limited to, those represented by the following formulas (1-2-1) to (1-2-17). Among these, from the viewpoint of charge transportability, formula (1-2-1), formula (1-2-2), formula (1-2-3), formula (1-2-5), formula (1-2-8), formula (1-2-9), formula (1-2-10), formula (1-2-11), formula (1-2-12), formula (1-2-13), formula (1-2-14), formula (1-2-15), formula (1-2-16) and formula (1-2-17) are preferred, and formula (1-2-1), formula (1-2-2), formula (1-2-3), formula (1-2-11), formula (1-2-12), formula (1-2-13), formula (1-2-14), formula (1-2-15), formula (1-2-16) and formula (1-2-17) are more preferred. In the following formulas (1-2-6) and (1-2-7), x1 is an integer of 1 to 14. Furthermore, Boc represents a tert-butoxycarbonyl group.

[0035]

[0036] In the structure of the above formula (2), the bonding position of other groups to the carbazole ring is preferably as shown in formula (2-1) in terms of steric hindrance.

[0037]

[0038] In the above formula (2-1), R 1 is as defined above.

[0039] Examples of the specific diamine include diamines represented by the following formulas (2-2) to (2-7). In particular, from the viewpoint of charge transport properties, diamines represented by formulas (2-3) to (2-7) are preferred, and diamines represented by formulas (2-4) to (2-7) are more preferred.

[0040]

[0041] In the above formula, R 1 The definition of is the same as in the above formula (1), and R 4 are each independently a hydrogen atom or a monovalent organic group, and R 5 are each independently a single bond or a divalent organic group. k2 is each independently 2 or 3. Any hydrogen atom on the benzene ring may be substituted with a monovalent organic group.

[0042] The above R 4 The monovalent organic group in 1 Examples include those exemplified in the explanation of R. 4 As the alkyl group, a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluoroalkyl group having 1 to 3 carbon atoms, a fluoroalkenyl group having 2 to 3 carbon atoms, a fluoroalkoxy group having 1 to 3 carbon atoms, and a tert-butoxycarbonyl group are preferred, a hydrogen atom and an alkyl group having 1 to 3 carbon atoms are more preferred, and a hydrogen atom and a methyl group are even more preferred.

[0043] R 5 The divalent organic group in the formula (2-8) includes a group having a structure of the following formula (2-8).

[0044]

[0045] In the above formula, R 6 represents a single bond, -O-, -COO-, -OCO-, -(CH2) r -, -O(CH2) s O-, -NR 61 --, --CONR 61 - and -NR 61 CO—, and k3 represents an integer of 1 to 5. 61 represents hydrogen or a monovalent organic group, r represents an integer of 1 to 5, and s represents an integer of 1 to 5. As the monovalent organic group, an alkyl group having 1 to 3 carbon atoms is preferred, and a methyl group is more preferred. *3 represents the site of bonding to the benzene ring in formulas (2-5) to (2-7), and *4 represents the site of bonding to the amino group in formulas (2-5) to (2-7).

[0046] Specific examples of the specific diamine include, but are not limited to, diamines represented by the following formulas (2-1-1) to (2-1-19). Among these, from the viewpoint of charge transport properties, formulas (2-1-1) to (2-1-7) and (2-1-10) to (2-1-17) are preferred, and formulas (2-1-1) to (2-1-7) and (2-1-15) to (2-1-17) are more preferred. In the following formulas, x2 is an integer of 1 to 14.

[0047]

[0048]

[0049] In the structure of the above formula (3), the bonding position of other groups to the benzene ring is preferably as shown in formula (3-1) in terms of steric hindrance.

[0050]

[0051] In the above formula (3-1), R 1 is as defined above.

[0052] Examples of the specific diamine include diamines represented by the following formulas (3-2) to (3-7). In particular, from the viewpoint of charge transport properties, diamines represented by formulas (3-3) to (3-7) are preferred, and diamines represented by formulas (3-4) to (3-7) are more preferred.

[0053]

[0054] In the above formula, R 1 The definition of is the same as in the above formula (1), and R 7 are each independently a hydrogen atom or a monovalent organic group, and R 8 are each independently a single bond or a divalent organic group. k4's are each independently 2 or 3. Any hydrogen atom on the benzene ring may be substituted with a monovalent organic group.

[0055] The above R 7 The monovalent organic group in 1 Examples include those exemplified in the explanation of R. 7 As the alkyl group, a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an alkenyl group having 2 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a fluoroalkyl group having 1 to 3 carbon atoms, a fluoroalkenyl group having 2 to 3 carbon atoms, a fluoroalkoxy group having 1 to 3 carbon atoms, and a tert-butoxycarbonyl group are preferred, a hydrogen atom and an alkyl group having 1 to 3 carbon atoms are more preferred, and a hydrogen atom and a methyl group are even more preferred.

[0056] R 8 The divalent organic group in the formula (3-8) includes a group having a structure of the following formula (3-8).

[0057]

[0058] In the above formula, R 9 represents a single bond, -O-, -COO-, -OCO-, -(CH2) r -, -O(CH2) s O-, -NR 91 --, --CONR 91 - and -NR 91 CO—, and k5 represents an integer of 1 to 5. 91represents hydrogen or a monovalent organic group, r represents an integer of 1 to 5, and s represents an integer of 1 to 5. As the monovalent organic group, an alkyl group having 1 to 3 carbon atoms is preferred, and a methyl group is more preferred. *5 represents the site of bonding to the benzene ring in formulas (3-5) to (3-7), and *6 represents the site of bonding to the amino group in formulas (3-5) to (3-7).

[0059] Specific examples of the specific diamine include, but are not limited to, diamines represented by the following formulas (3-1-1) to (3-1-19). Among these, from the viewpoint of charge transport properties, formulas (3-1-1) to (3-1-7) and (3-1-10) to (3-1-17) are preferred, and formulas (3-1-1) to (3-1-7) and (3-1-15) to (3-1-17) are more preferred. In the following formulas, x3 is an integer of 1 to 14.

[0060]

[0061]

[0062] <Method for synthesizing specific diamine> The method for synthesizing the specific diamine is not particularly limited and may be a known method. For example, the specific diamine can be synthesized by the methods described in WO 2018 / 062197, WO 2018 / 110354, etc.

[0063] <Other diamines: diamines other than those mentioned above> The diamine component for obtaining the specific polymer may contain a diamine component other than the specific diamines mentioned above. Examples of the other diamine components include those represented by the following formula (E1).

[0064]

[0065] In the above formula (E1), A 1 and A 2 each independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkynyl group having 2 to 5 carbon atoms; Y 1 represents a divalent organic group.

[0066] Examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an i-butyl group, an s-butyl group, a t-butyl group, and an n-pentyl group.

[0067] Examples of the alkenyl group having 2 to 5 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, and n-1-pentenyl.

[0068] Examples of the alkynyl group having 2 to 5 carbon atoms include ethynyl, n-1-propynyl, n-2-propynyl, n-1-butynyl, n-2-butynyl, n-3-butynyl, 1-methyl-2-propynyl, n-1-pentynyl, n-2-pentynyl, n-3-pentynyl, n-4-pentynyl, 1-methyl-n-butynyl, 2-methyl-n-butynyl, 3-methyl-n-butynyl, and 1,1-dimethyl-n-propynyl.

[0069] Among these, A is preferred from the viewpoint of monomer reactivity. 1 and A 2 is preferably a hydrogen atom or a methyl group.

[0070] Y 1 Examples of the x4 include groups represented by the following formulae (Y-1) to (Y-170). In the following formulae, x4 is an integer of 1 to 14, and where there is a preferred range, that range is also noted. In addition, where there is no description of the range of x4, an integer of 1 to 6 is preferred. In the following formulae, Me represents a methyl group, and Boc represents a tert-butoxycarbonyl group.

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084]

[0085]

[0086]

[0087]

[0088]

[0089]

[0090]

[0091]

[0092]

[0093] The other diamines described above may be used singly or in combination of two or more. When the diamine component contains other diamines, the content of the specific diamine in the diamine component can be preferably 10 to 100 mol %, more preferably 30 to 100 mol %, and even more preferably 50 to 100 mol %.

[0094] <Tetracarboxylic Acid Component> Examples of the tetracarboxylic acid component for obtaining the specific polymer include tetracarboxylic acid, tetracarboxylic acid dianhydride, tetracarboxylic acid dihalide, tetracarboxylic acid dialkyl ester, and tetracarboxylic acid dialkyl ester dihalide, and in the present invention, these are also collectively referred to as tetracarboxylic acid component.

[0095] As the tetracarboxylic acid component, tetracarboxylic acid dianhydride and its derivatives, such as tetracarboxylic acid, tetracarboxylic acid dihalide, tetracarboxylic acid dialkyl ester, and tetracarboxylic acid dialkyl ester dihalide (collectively referred to as a first tetracarboxylic acid component) can also be used.

[0096] Examples of the tetracarboxylic dianhydride include aliphatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, aromatic tetracarboxylic dianhydrides, etc. Specific examples of these include those in the following groups [1] to [5].

[0097] [1] Examples of aliphatic tetracarboxylic dianhydrides include 1,2,3,4-butanetetracarboxylic dianhydride.

[0098] [2] Examples of the alicyclic tetracarboxylic acid dianhydride include acid dianhydrides represented by the following formulae (X1-1) to (X1-13).

[0099]

[0100]

[0101] In the above formulas (X1-1) to (X1-4), R 1a ~R 21a R each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group. M represents a hydrogen atom or a methyl group. a represents a tetravalent organic group represented by the following formulas (Xa-1) to (Xa-7).

[0102]

[0103] [3] 3-oxabicyclo[3.2.1]octane-2,4-dione-6-spiro-3'-(tetrahydrofuran-2',5'-dione), 3,5,6-tricarboxy-2-carboxymethylnorbornane-2:3,5:6-dianhydride, 4,9-dioxatricyclo[5.3.1.02,6]undecane-3,5,8,10-tetraone, and the like.

[0104] [4] Examples of aromatic tetracarboxylic dianhydrides include pyromellitic anhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, and acid dianhydrides represented by the following formulas (X2-1) to (X2-10).

[0105]

[0106]

[0107] [5] Acid dianhydrides represented by the following formulae (X3-1) to (X3-9), and tetracarboxylic acid dianhydrides described in JP-A-2010-97188, etc.

[0108]

[0109]

[0110] The tetracarboxylic acid components described above may be used alone or in combination of two or more. Depending on the properties required for the organic photosensor element or charge transport layer, one type may be used alone or two or more types may be used in combination, and when two or more types are used in combination, the ratio of the two or more types may be appropriately adjusted.

[0111] <Method for Producing Specific Polymer> As described above, the specific polymer can be obtained by reacting a diamine component with a tetracarboxylic acid component. For example, the method involves reacting a diamine component consisting of one or more diamines with at least one tetracarboxylic acid component selected from the group consisting of tetracarboxylic dianhydrides and derivatives of such tetracarboxylic acids to obtain a polyamic acid. Specifically, a method is used in which a primary or secondary diamine is polycondensed with a tetracarboxylic dianhydride to obtain a polyamic acid.

[0112] To obtain a polyamic acid alkyl ester, a method of polycondensing a tetracarboxylic acid in which the carboxylic acid group has been dialkyl-esterified with a primary or secondary diamine, a method of polycondensing a tetracarboxylic acid dihalide in which the carboxylic acid group has been halogenated with a primary or secondary diamine, or a method of converting the carboxy group of a polyamic acid into an ester can be used.To obtain a polyimide, a method of ring-closing the above polyamic acid or polyamic acid alkyl ester to form a polyimide can be used.

[0113] The reaction between the diamine component and the tetracarboxylic acid component is typically carried out in a solvent. The solvent used is not particularly limited, as long as it dissolves the resulting polyimide precursor. Examples of the solvent include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, γ-butyrolactone, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, 3-methoxy-N,N-dimethylpropanamide, dimethyl sulfoxide, and 1,3-dimethyl-imidazolidinone. Furthermore, when the polyimide precursor has high solvent solubility, methyl ethyl ketone, cyclohexanone, cyclopentanone, 4-hydroxy-4-methyl-2-pentanone, or solvents represented by the following formulas [s1] to [s3] may also be used.

[0114]

[0115] In formula [s1], D s1 represents an alkyl group having 1 to 3 carbon atoms.s2 represents an alkyl group having 1 to 3 carbon atoms. s3 represents an alkyl group having 1 to 4 carbon atoms.

[0116] Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an i-butyl group, an s-butyl group, a t-butyl group, etc. Examples of the alkyl group having 1 to 3 carbon atoms include the above alkyl groups having 1 to 4 carbon atoms, but having 1 to 3 carbon atoms.

[0117] These solvents may be used alone or in combination of two or more. Even if the solvent does not dissolve the polyimide precursor, it may be mixed with the above-mentioned solvent as long as the resulting polyimide precursor does not precipitate. Furthermore, moisture in the solvent inhibits the polymerization reaction and may cause hydrolysis of the resulting polyimide precursor, so it is preferable to use a solvent that has been dehydrated and dried.

[0118] When the diamine component and the tetracarboxylic acid component are reacted in a solvent, any of the following methods may be used: a method in which a solution in which the diamine component is dispersed or dissolved in a solvent is stirred, and the tetracarboxylic acid component is added as is or after being dispersed or dissolved in the solvent; a method in which the diamine component is added to a solution in which the tetracarboxylic acid component is dispersed or dissolved in a solvent; a method in which the diamine component and the tetracarboxylic acid component are added alternately; etc. When a plurality of diamine components or a plurality of tetracarboxylic acid components are used for the reaction, they may be reacted in a pre-mixed state, or may be reacted individually in sequence, or low molecular weight components that have been reacted individually may be mixed and reacted to form a polymer.

[0119] The temperature at which the diamine component and the tetracarboxylic acid component are polycondensed can be selected from any temperature between -20 and 150°C, but is preferably in the range of -5 to 100°C. The reaction can be carried out at any concentration, but if the concentration is too low, it becomes difficult to obtain a high-molecular-weight polymer, and if the concentration is too high, the viscosity of the reaction solution becomes too high, making uniform stirring difficult. Therefore, the concentration is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. The reaction can also be carried out at a high concentration in the early stages, with additional solvent added thereafter.

[0120] In the polymerization reaction of the polyimide precursor, the ratio of the total number of moles of the diamine component to the total number of moles of the tetracarboxylic acid component is preferably 0.8 to 1.2. As in a typical polycondensation reaction, the closer this molar ratio is to 1.0, the higher the molecular weight of the resulting polyimide precursor will be.

[0121] The polyimide is obtained by ring-closing the polyimide precursor, and the ring-closure rate of the amic acid groups in this polyimide (also called the imidization rate) does not necessarily need to be 100% and can be adjusted as desired depending on the application and purpose. Methods for imidizing the polyimide precursor include thermal imidization, in which a solution of the polyimide precursor is heated as is, and catalytic imidization, in which a catalyst is added to a solution of the polyimide precursor.

[0122] The temperature for thermally imidizing the polyimide precursor in a solution is 100 to 400°C, preferably 120 to 250°C, and it is preferable to carry out the imidization while removing water produced by the imidization reaction from the system. Catalytic imidization of the polyimide precursor can be carried out by adding a basic catalyst and an acid anhydride to a solution of the polyimide precursor and stirring the mixture at -20 to 250°C, preferably 0 to 180°C.

[0123] The amount of the basic catalyst is 0.5 to 30 times, preferably 2 to 20 times, the molar amount of the amic acid group, and the amount of the acid anhydride is 1 to 50 times, preferably 3 to 30 times, the molar amount of the amic acid group. Examples of basic catalysts include pyridine, triethylamine, trimethylamine, tributylamine, and trioctylamine. Among these, pyridine is preferred because it has an appropriate basicity for promoting the reaction. Examples of acid anhydrides include acetic anhydride, trimellitic anhydride, and pyromellitic anhydride. Acetic anhydride is particularly preferred because it facilitates purification after completion of the reaction. The imidization rate by catalytic imidization can be controlled by adjusting the amount of catalyst, reaction temperature, and reaction time.

[0124] To recover the resulting polyimide precursor or polyimide from a reaction solution of the polyimide precursor or polyimide, the reaction solution may be precipitated by pouring the reaction solution into a solvent. Examples of solvents used for precipitation include methanol, ethanol, isopropyl alcohol, acetone, hexane, butyl cellosolve, heptane, methyl ethyl ketone, methyl isobutyl ketone, toluene, benzene, and water. The polymer precipitated by pouring into the solvent can be recovered by filtration and then dried at normal or reduced pressure, or at room temperature or by heating. Furthermore, the polymer precipitated and recovered can be redissolved in a solvent and reprecipitated and recovered 2 to 10 times to reduce the amount of impurities in the polymer. Examples of solvents used in this process include alcohols, ketones, and hydrocarbons. Using three or more solvents selected from these solvents is preferred because it further increases the efficiency of purification.

[0125] More specific examples of the method for producing the polyamic acid alkyl ester of the present invention are shown below in (1) to (3).

[0126] (1) Production method by esterification reaction of polyamic acid: This method involves producing polyamic acid from, for example, a diamine component and a tetracarboxylic acid component, and then chemically reacting its carboxyl group (COOH group), i.e., esterifying it, to produce a polyamic acid alkyl ester. The esterification reaction involves reacting polyamic acid with an esterifying agent in the presence of a solvent at −20 to 150° C. (preferably 0 to 50° C.) for 30 minutes to 24 hours (preferably 1 to 4 hours).

[0127] The esterifying agent is preferably one that can be easily removed after the esterification reaction, and examples thereof include N,N-dimethylformamide dimethyl acetal, N,N-dimethylformamide diethyl acetal, N,N-dimethylformamide dipropyl acetal, N,N-dimethylformamide dineopentyl butyl acetal, N,N-dimethylformamide di-t-butyl acetal, 1-methyl-3-p-tolyltriazene, 1-ethyl-3-p-tolyltriazene, 1-propyl-3-p-tolyltriazene, and 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride. The amount of the esterifying agent used is preferably 2 to 6 molar equivalents per mole of repeating units of polyamic acid. Of these, 2 to 4 molar equivalents are preferred.

[0128] The solvent used in the esterification reaction may be the same as that used in the reaction between the diamine component and the tetracarboxylic acid component, in terms of the solubility of the polyamic acid in the solvent. Among these, N,N-dimethylformamide, N,N-diethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-diethylacetamide, 3-methoxy-N,N-dimethylpropanamide, or γ-butyrolactone is preferred. These solvents may be used alone or in combination of two or more. The concentration of polyamic acid in the solvent used in the esterification reaction is preferably 1 to 30% by mass, in terms of preventing precipitation of the polyamic acid. Of these, 5 to 20% by mass is preferred.

[0129] (2) Production method by reacting a diamine component with a tetracarboxylic acid diester dichloride. This method involves reacting a diamine component with a tetracarboxylic acid diester dichloride in the presence of a base and a solvent at −20 to 150° C. (preferably 0 to 50° C.) for 30 minutes to 24 hours (preferably 1 to 4 hours). Examples of the base that can be used include pyridine, triethylamine, and 4-dimethylaminopyridine. Of these, pyridine is preferred because the reaction proceeds mildly. The amount of base used is preferably an amount that can be easily removed after the reaction, and is preferably 2 to 4 times the molar amount of the tetracarboxylic acid diester dichloride, and more preferably 2 to 3 times the molar amount.

[0130] Examples of the solvent include those used in the reaction between the diamine component and the tetracarboxylic acid component, from the viewpoint of the solubility of the resulting polymer, i.e., the polyamic acid alkyl ester, in the solvent. Among these, N,N-dimethylformamide, N,N-diethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-diethylacetamide, 3-methoxy-N,N-dimethylpropanamide, and γ-butyrolactone are preferred. These solvents may be used alone or in combination of two or more.

[0131] The concentration of the polyamic acid alkyl ester in the solvent used in the reaction is preferably 1 to 30% by mass, since precipitation of the polyamic acid alkyl ester is unlikely to occur. Of these, 5 to 20% by mass is preferred. Furthermore, in order to prevent hydrolysis of the tetracarboxylic acid diester dichloride, it is preferable that the solvent used in preparing the polyamic acid alkyl ester be as dehydrated as possible. Furthermore, it is preferable that the reaction be carried out in a nitrogen atmosphere to prevent the inclusion of outside air.

[0132] (3) Method of producing by reaction of a diamine component with a tetracarboxylic acid diester. This method is, for example, a method of polycondensation reaction of a diamine component with a tetracarboxylic acid diester in the presence of a condensing agent, a base, and a solvent at 0 to 150°C (preferably 0 to 100°C) for 30 minutes to 24 hours (preferably 3 to 15 hours).

[0133] Examples of the condensing agent that can be used include triphenyl phosphite, dicyclohexylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, N,N'-carbonyldiimidazole, dimethoxy-1,3,5-triazinylmethylmorpholinium, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborate, O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate, and (2,3-dihydro-2-thioxo-3-benzoxazolyl)diphenyl phosphonate. The amount of the condensing agent used is preferably 2 to 3 times, and particularly preferably 2 to 2.5 times, the molar amount of the tetracarboxylic acid diester.

[0134] The base may be a tertiary amine such as pyridine or triethylamine. The amount of base used is preferably an amount that can be easily removed after the polycondensation reaction, and is preferably 2 to 4 times, and more preferably 2 to 3 times, the molar amount of the diamine component. The solvent used in the polycondensation reaction may be the same as that used in the reaction between the diamine component and the tetracarboxylic acid component, from the viewpoint of the solubility of the resulting polymer, i.e., the polyamic acid alkyl ester, in the solvent. Of these, N,N-dimethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, or γ-butyrolactone is preferred. These solvents may be used alone or in combination of two or more.

[0135] Furthermore, in the polycondensation reaction, the reaction can be efficiently promoted by adding a Lewis acid as an additive. As the Lewis acid, lithium halides such as lithium chloride and lithium bromide are preferred. The amount of the Lewis acid used is preferably 0.1 to 10 times by mole relative to the diamine component. In particular, 2.0 to 3.0 times by mole is preferred.

[0136] To recover a polyamic acid alkyl ester from a solution of the polyamic acid alkyl ester obtained by the above methods (1) to (3), the reaction solution may be precipitated by pouring the reaction solution into a solvent. Examples of solvents used for precipitation include water, methanol, ethanol, 2-propanol, hexane, butyl cellosolve (ethylene glycol monobutyl ether), acetone, and toluene. The polymer precipitated by pouring into the solvent is preferably washed multiple times with the solvent to remove the additives and catalysts used above. After washing and filtration, the polymer can be dried under atmospheric pressure or reduced pressure, at room temperature, or by heating. Furthermore, the precipitated polymer can be redissolved in a solvent and reprecipitated and recovered 2 to 10 times to reduce the amount of impurities in the polymer. The polyamic acid alkyl ester is preferably produced by the above method (2) or (3).

[0137] The average molecular weight of the polyimide polymer is not particularly limited, but its number average molecular weight (Mn) is usually 2,000 to 1,000,000, and preferably 2,000 to 100,000. Its weight average molecular weight (Mw) is usually 2,000 to 3,000,000, and preferably 2,000 to 500,000. In the present invention, the average molecular weight is a polyethylene oxide-equivalent value determined by gel permeation chromatography.

[0138] <Other Charge Transporting Materials> The charge transporting composition of the present invention may contain a conductive polymer such as polythiophene or polyaniline for the purpose of adjusting the charge transporting ability of the charge transporting layer.

[0139] [Crosslinking Agent] The crosslinking agent contained in the charge-transporting composition of the present invention is at least one compound selected from the group consisting of partial structures represented by the following formulas (b1) and (b2), compounds having two or more epoxy groups, compounds having two or more oxetane rings, and compounds having two or more oxazoline rings. In the present invention, the use of such a crosslinking agent can improve the solvent resistance of the resulting charge-transporting thin film, and is expected to further improve the PCE of the resulting device. Each compound may be used alone or in combination of two or more types.

[0140] (In formula (b1), R b1 and R b1’ are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or *b4-CH2-O-R b11 represents R b11 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and *b4 represents R b1 and R b1’ represents a bond to the carbon atom to which it is bonded, and R b2 and R b2’ each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, n1 represents 0 or 1, and *b1 and *b2 represent a bond. b represents an (n2+n3+1)-valent aromatic ring, R b3 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and when n3 is 0, R b3 At least one of represents a hydrogen atom, n2 represents an integer of 1 to 6, n3 represents an integer of 0 to 6, and *b3 represents a bond.

[0141] The compound having two or more of at least one type of partial structure selected from the group consisting of partial structures represented by the above formulas (b1) and (b2) may be a compound having two or more partial structures represented by formula (b1), or may be a compound having two or more partial structures represented by formula (b2).

[0142] Preferred embodiments of the compound having at least two or more partial structures represented by the above formula (b1) include compounds represented by the following formulas (B1-1) to (B1-3). [(In formula (B1-1), A b represents an organic group having a valence of nx; R b4 each independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a partial structure represented by the following formula (b1-1), nx represents an integer of 2 to 6, R b1 、 R b2 、 R b1’ and R b2’ In formulas (B1-2) and (B1-3), R b5 and R b6 each independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a partial structure represented by the following formula (b1-1), or a partial structure represented by the following formula (b1-2), and a plurality of R b5 At least two of R represent a partial structure represented by the following formula (b1-1) or a partial structure represented by the following formula (b1-2), b6 At least two of the above represent a partial structure represented by the following formula (b1-1). (In the formula, R b1 , R b1’ , R b2 , R b2’ , n1 have the same meaning as above, R b7 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, n4 represents an integer of 1 to 6, and * represents a bond.

[0143] Examples of the nx-valent organic group include an nx-valent hydrocarbon group, an nx-valent heteroatom-containing group containing a group having a heteroatom at least in one of the carbon-carbon spaces of the hydrocarbon group and at the end of the hydrocarbon group, an nx-valent group in which some or all of the hydrogen atoms in the hydrocarbon group and the heteroatom-containing group have been substituted with substituents, a divalent heterocycle, or a divalent organic group in which these divalent heterocycles are linked by a single bond, etc. Examples of the heterocycle include aromatic heterocycles such as a pyridine ring and a pyrimidine ring; and aliphatic heterocycles such as a piperidine ring and a piperazine ring.

[0144] Examples of the nx-valent hydrocarbon group include nx-valent groups obtained by removing nx hydrogen atoms from hydrocarbons such as chain hydrocarbons having 1 to 30 carbon atoms, such as alkanes such as methane, ethane, propane, and butane; alkenes such as ethylene, propylene, butene, and pentene; and alkynes such as ethyne, propyne, butyne, and pentyne; alicyclic hydrocarbons having 3 to 30 carbon atoms, such as cycloalkanes such as cyclopropane, cyclobutane, cyclopentane, cyclohexane, norbornane, and adamantane; cycloalkenes such as cyclopropene, cyclobutene, cyclopentene, cyclohexene, and norbornene; and aromatic hydrocarbons having 6 to 30 carbon atoms, such as benzene, toluene, xylene, mesitylene, naphthalene, methylnaphthalene, dimethylnaphthalene, and anthracene. However, the chain hydrocarbons do not need to be composed solely of chain hydrocarbons, and may partially contain alicyclic hydrocarbons or aromatic hydrocarbons.

[0145] Examples of the group having a hetero atom include a group having at least one atom selected from the group consisting of an oxygen atom, a nitrogen atom, a silicon atom, a phosphorus atom, and a sulfur atom, and examples of the group having a hetero atom include —O—, —NR x1 - (R x1 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. ), -CO-, -S-, groups combining these, heterocycles, or divalent organic groups in which these divalent heterocycles are linked by a single bond, etc. Specific examples of the heterocycle include the structures exemplified above for the divalent heterocycle.

[0146] Examples of the substituent include halogen atoms such as a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom; alkoxy groups such as a methoxy group, an ethoxy group, and a propoxy group; alkoxycarbonyl groups such as a methoxycarbonyl group and an ethoxycarbonyl group; alkoxycarbonyloxy groups such as a methoxycarbonyloxy group and an ethoxycarbonyloxy group; a cyano group, and a nitro group.

[0147] Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and a cyclopropyl group.

[0148] Preferred examples of the compound represented by the above formula (B1-1) include compounds represented by the following formulas (B1a) to (B1e).

[0149] [R b21 are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or —CH—CR b1 R b1’ represents —OH, and mx represents an integer of 1 to 8. b1 , R b1’ has the same meaning as above. b22 each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 11 , L 13 are each independently a single bond, —NR x1 - (R x1 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.), —(CH2) my - (my is an integer from 1 to 6), or *x1-(CH2) my -NR x2 -(my is an integer from 1 to 6. R x2 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. *x1 represents a bond to the carbonyl carbon atom. 12 is a single bond, -NR x1 - (R x1 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.), —(CH2) my -(my is an integer of 1 to 6), -CH=CH-, -CONH- or -C(=O)-O-. mz is an integer of 0 to 1. L 21 , L 22 , L 23 , L 31 are each independently a single bond or -(CH2) my - (where my is an integer of 1 to 6). b21 and R b22 may be the same or different.

[0150] Preferred specific examples of the compound represented by formula (B1-1) above include compounds represented by formulas (B1-1-1) to (B1-1-14) below, but are not limited thereto.

[0151]

[0152]

[0153] Preferred specific examples of the compound represented by formula (B1-2) above include compounds represented by formulas (B1-2-1) to (B1-2-2) below, but are not limited thereto.

[0154]

[0155] Preferred specific examples of the compound represented by formula (B1-3) above include compounds represented by formulas (B1-3-1) and (B1-3-2) below, but are not limited thereto.

[0156]

[0157] A preferred embodiment of the compound having at least two partial structures represented by the above formula (b2) is a compound represented by the following formula (B2-1).

[0158] (R b3 , n2 and n3 are R in formula (b2) b3 , n2, n3, and when at least one of n3 is 0, R b3 At least one of Y represents a hydrogen atom. b represents an aromatic ring, and any hydrogen atom in the aromatic ring may be substituted with an alkyl group having 1 to 3 carbon atoms, a halogen atom, an alkoxy group having 1 to 3 carbon atoms, or a vinyl group. b represents a single bond, a saturated hydrocarbon group having 1 to 10 carbon atoms, -NR Z - (R Z represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 1 -Q 1 -P 2 - (P 1 and P 2 each independently represents an alkyl group having 1 to 5 carbon atoms; Q 1represents an aromatic ring. The saturated hydrocarbon groups may be bonded in whole or in part to form a cyclic structure, and any hydrogen atom may be substituted with a fluorine atom. ny represents an integer of 2 to 6.

[0159] Z b Specific examples of the saturated hydrocarbon group in the formula (I) include an ny-valent organic group obtained by removing ny hydrogen atoms from the above-mentioned alkane having 1 to 10 carbon atoms or cycloalkane having 1 to 10 carbon atoms. Note that a part of the alkane may be constituted by cycloalkane.

[0160] Y b , Q 1 Specific examples of the aromatic ring in the formula (I) include aromatic hydrocarbon rings such as a benzene ring, a naphthalene ring, an anthracene ring, a fluorene ring, an azulene ring, and an indene ring, and aromatic heterocycles such as a pyrrole ring, an imidazole ring, an oxazole ring, a thiazole ring, a pyrazole ring, a pyridine ring, a pyrimidine ring, a quinoline ring, an isoquinoline ring, a carbazole ring, a purine ring, a thiadiazole ring, a pyridazine ring, a triazine ring, a triazole ring, a pyrazine ring, a benzimidazole ring, a phenanthroline ring, an indole ring, a quinoxaline ring, a benzothiazole ring, a phenothiazine ring, an acridine ring, and an oxazole ring. Among these, a benzene ring, a naphthalene ring, a fluorene ring, an anthracene ring, a pyrrole ring, an imidazole ring, a pyrazole ring, a pyridine ring, a pyrimidine ring, a quinoline ring, an isoquinoline ring, a carbazole ring, a pyridazine ring, a pyrazine ring, a benzimidazole ring, an indole ring, a quinoxaline ring, and an acridine ring are preferred, a benzene ring, a naphthalene ring, a pyridine ring, and a carbazole ring are more preferred, and a benzene ring and a pyridine ring are even more preferred.

[0161] Specific examples of the compound having the partial structure represented by formula (b2) above include compounds represented by formulas (B2-1-1) to (B2-1-6) below, but are not limited to these.

[0162]

[0163] Examples of compounds having two or more epoxy groups include bisphenol A type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, alicyclic epoxy resins, glycidyl ester type epoxy resins, glycidyl diamine type epoxy resins, heterocyclic epoxy resins, and acrylic resins having epoxy groups. Commercially available products can be used for these, and specific examples include Epolite 400E and 3002 (manufactured by Kyoeisha Chemical Co., Ltd.), Epicoat 828 and 152, and Epoxy Novolac 180S (manufactured by Japan Epoxy Resins Co., Ltd.). Among these, glycidyl diamine type epoxy resins are preferred in the present invention, and are represented by the following formula (B E ) is more preferred.

[0164] (In the formula, R E is a divalent organic group having an aromatic ring or a cyclohexane ring and having 6 to 40 carbon atoms, provided that the above R E may contain an oxygen atom or a sulfur atom.

[0165] The above formula (B E Specific examples of the compound represented by the following formula (B E -1) to (B E -7)

[0166] Specific examples of compounds having two or more oxetane rings include 1,4-bis{[(3-ethyl-3-oxetanyl)methoxy]methyl}benzene (Aronoxetane OXT-121 (XDO)), di[2-(3-oxetanyl)butyl]ether (Aronoxetane OXT-221 (DOX)), 1,4-bis[(3-ethyloxetan-3-yl)methoxy]benzene (HQOX), 1,3-bis[(3-ethyloxetan-3-yl)methoxy]methyl]benzene (HQOX), bis[(3-ethyloxetan-3-yl)methoxy]benzene (RSOX), 1,2-bis[(3-ethyloxetan-3-yl)methoxy]benzene (CTOX), 4,4'-bis[(3-ethyloxetan-3-yl)methoxy]biphenyl (4,4'-BPOX), 2,2'-bis[(3-ethyl-3-oxetanyl)methoxy]biphenyl (2,2'-BPOX), 3,3',5,5'-tetramethyl[4,4'-bis(3-ethyloxetan-3-yl)methoxy]biphenyl (T M-BPOX), 2,7-bis[(3-ethyloxetan-3-yl)methoxy]naphthalene (2,7-NpDOX), 1,6-bis[(3-ethyloxetan-3-yl)methoxy]-2,2,3,3,4,4,5,5-octafluorohexane (OFH-DOX), 2,4,6-O-tris[(3-ethyloxetan-3-yl)methyl]cyanuric acid, ethers of bisphenol A and 3-ethyl-3-chloromethyloxetane (abbreviated as OXC). etherified product of bisphenol F and OXC (BisFOX), etherified product of phenol novolak and OXC (PNOX), etherified product of cresol novolak and OXC (CNOX), oxetanyl silsesquioxane (OX-SQ), silicon alkoxide of 3-ethyl-3-hydroxymethyl oxetane (OX-SC) (the names in parentheses are trade names or developed product names, manufactured by Toagosei Co., Ltd.), ETARNACOLL OXBP (manufactured by Ube Industries, Ltd.), and hydroxymethyl oxetane derivatives of the following formula (B C In the present invention, among these, Aron Oxetane, OX-SC, OXT-121, OXT-221, PNOX-1009 (all manufactured by Toagosei Co., Ltd.) and ETARNACOLL OXBP (manufactured by Ube Industries, Ltd.) are preferred, with OX-SC, OXT-121, OXT-221 and PNOX-1009 being more preferred.

[0167]

[0168] Specific examples of compounds having two or more oxazoline rings include 2,2'-bis(2-oxazoline), 2,2'-bis(4-methyl-2-oxazoline), 2,2'-bis(5-methyl-2-oxazoline), 2,2'-bis(5,5'-dimethyloxazoline), 2,2'-bis(4,4,4',4'-tetramethyl-2-oxazoline), 1,2-bis(2-oxazolin-2-yl)ethane, 1,4-bis(2-oxazolin-2-yl)butane, and 1,6-bis(2-oxazoline). -2-yl)hexane, 1,8-bis(2-oxazolin-2-yl)octane, 1,4-bis(2-oxazolin-2-yl)cyclohexane, 1,2-bis(2-oxazolin-2-yl)benzene, 1,3-bis(2-oxazolin-2-yl)benzene, 1,4-bis(2-oxazolin-2-yl)benzene, 1,2-bis(5-methyl-2-oxazolin-2-yl)benzene, 1,3-bis(5-methyl-2-oxazolin-2-yl)benzene, 1,4-bis(5-methyl 1,4-bis(4,4'-dimethyl-2-oxazolin-2-yl)benzene, 1,4-bis(4,5-dihydro-2-oxazolyl)benzene, 1,3-bis(4,5-dihydro-2-oxazolyl)benzene, 2,3-bis(4-isopropenyl-2-oxazolin-2-yl)butane, 2,2'-bis(4-benzyl-2-oxazoline), 2,6-bis(4-isopropyl-2-oxazolin-2-yl)pyridine, 2,2'-isopropyl Examples of compounds include 2,2'-isopropylidenebis(4-tert-butyl-2-oxazoline), 2,2'-isopropylidenebis(4-phenyl-2-oxazoline), 2,2'-methylenebis(4-tert-butyl-2-oxazoline), and 2,2'-methylenebis(4-phenyl-2-oxazoline), 1,2,4-tris(2-oxazolin-2-yl)benzene, and compounds such as polymers and oligomers having an oxazoline group, such as EPOCROS (trade name, manufactured by Nippon Shokubai Co., Ltd.).

[0169] From the viewpoint of optimally achieving the effects of the present invention, the molecular weight of the crosslinking agent is preferably 2,000 or less, more preferably 200 to 1,800, and even more preferably 200 to 1,500.

[0170] The content of the crosslinking agent is preferably 0.01 to 2.0, more preferably 0.01 to 1.0, and even more preferably 0.01 to 0.5, relative to the charge transport substance in terms of mass ratio 1. The crosslinking agents may be used alone or in combination of two or more.

[0171] [Organic Solvent] The charge transporting composition is generally in the form of a coating liquid so that it can form a uniform thin film. The charge transporting composition of the present invention is also preferably in the form of a coating liquid containing the above polymer component and an organic solvent that dissolves the polymer component.

[0172] The organic solvent contained in the charge transport composition is not particularly limited as long as it can uniformly dissolve the polymer component. Specific examples include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, dimethyl sulfoxide, N,N-diethylformamide, N,N-diethylformamide, 3-methoxy-N,N-dimethylpropanamide, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, methyl ethyl ketone, cyclohexanone, and cyclopentanone. Among these, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, 3-methoxy-N,N-dimethylpropanamide, and γ-butyrolactone are preferred.

[0173] In addition to the above-mentioned solvents, the organic solvent contained in the charge-transporting composition of the present invention may also be a solvent that improves the coatability of the charge-transporting composition when applied and the surface smoothness of the coating film. Specific examples of such organic solvents are listed below, but are not limited to these.

[0174] For example, ethanol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, isopentyl alcohol, tert-pentyl alcohol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, cyclohexanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol, 2,6-dimethyl-4-heptanol, 1,2-ethanediol, 1,2-propanediol, 1,3-propane Diol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, diisopropyl ether, dipropyl ether, dibutyl ether, dihexyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, 1,2-butoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, diethylene glycol methyl ethyl ether, diethylene glycol dibutyl ether, 2-pentanone, 3-pentanone, 2-hexanone, 2-heptanone, 4-heptanone, 2,6-dimethyl-4-heptanone, 4,6-dimethyl-2-heptanone, 3-ethoxybutyl acetate, 1-methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, ethylene glycol monoacetate, ethylene glycol diacetate, propylene carbonate, ethylene carbonate, 2-(methoxymethoxy)ethanol, ethylene glycol monobutyl ether, ethylene glycol monoisoamyl ether, ethylene glycol monohexyl ether, 2-(hexyloxy)ethanol, furfuryl alcohol, diethylene glycol, propylene glycol, propylene glycol monobutyl ether, 1-(butoxyethoxy)propanol, propylene glycol monomethyl ether acetate, dipropylene glycol, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol Ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monoacetate, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, 2-(2-ethoxyethoxy)ethyl acetate, diethylene glycol acetate, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methyl lactate, ethyl lactate, methyl acetate, acetic acid Examples of lactate include ethyl, n-butyl acetate, propylene glycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, and isoamyl lactate.

[0175] Among these, it is preferable to use 1-hexanol, cyclohexanol, 1,2-ethanediol, 1,2-propanediol, propylene glycol monobutyl ether, diethylene glycol diethyl ether, 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monobutyl ether, or dipropylene glycol dimethyl ether as the organic solvent.

[0176] These organic solvents may be used alone or in combination of two or more. The type and content of such organic solvents are appropriately selected depending on the coating device, coating conditions, coating environment, etc. of the charge transport composition.

[0177] [Electron-Accepting Dopant Substance] The charge-transporting composition of the present invention may contain an electron-accepting dopant substance (hereinafter, sometimes simply referred to as a "dopant substance") for the purpose of adjusting the ionization potential, improving the charge-transporting ability, etc., depending on the application of the thin film to be obtained. The dopant substance is not particularly limited as long as it is soluble in at least one solvent used in the charge-transporting composition, and both inorganic and organic dopant substances can be used.

[0178] As the inorganic dopant substance, heteropolyacids are preferred, and specific examples thereof include phosphomolybdic acid, silicomolybdic acid, phosphotungstic acid, phosphotungstomolybdic acid, and silicotungstic acid.

[0179] 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 (D1) or a Dawson type chemical structure shown in formula (D2), and are formed by condensation of an isopolyacid, which is an oxyacid of vanadium (V), molybdenum (Mo), tungsten (W), etc., with an oxyacid of a different element. Examples of such oxyacids of different elements include oxyacids of silicon (Si), phosphorus (P), and arsenic (As).

[0180]

[0181] Specific examples of heteropolyacids include phosphomolybdic acid, silicomolybdic acid, phosphotungstic acid, silicotungstic acid, and phosphotungstomolybdic acid, which may be used alone or in combination of two or more. The heteropolyacids used in the present invention are commercially available or can be synthesized by known methods. In particular, when one type of heteropolyacid is used, that one type of heteropolyacid is preferably phosphotungstic acid or phosphomolybdic acid, with phosphotungstic acid being the most preferred. Furthermore, when two or more types of heteropolyacids are used, one of the two or more types of heteropolyacids is preferably phosphotungstic acid or phosphomolybdic acid, with phosphotungstic acid being more preferred.

[0182] In addition, the heteropolyacid may be used in the present invention regardless of whether it has a large or small number of elements in the structure represented by the general formula in quantitative analysis such as elemental analysis, as long as it is a commercially available product or is appropriately synthesized according to a known synthesis method.

[0183] That is, for example, phosphotungstic acid generally has the chemical formula H3 (PW 12 O 40 )·nH2O, and phosphomolybdic acid has the chemical formula H3(PMo 12 O 40 )·nHO, but whether the number of P (phosphorus), O (oxygen), W (tungsten), or Mo (molybdenum) in this formula is high or low in quantitative analysis, it can be used in the present invention as long as it is obtained as a commercially available product 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 a 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.

[0184] When the charge-transporting composition of the present invention contains a heteropolyacid, the content thereof is preferably about 0.001 to 50 parts by mass, more preferably about 0.05 to 10 parts by mass, and even more preferably about 0.1 to 5.0 parts by mass, per 1 part of the charge-transporting substance.

[0185] Examples of organic dopant substances include arylsulfonic acid, arylsulfonic acid esters, ionic compounds consisting of a specific anion and its counter cation, tetracyanoquinodimethane derivatives, benzoquinone derivatives, etc. In the present invention, ionic compounds are preferably used in view of the ease of doping the specific polymer.

[0186] As the arylsulfonic acid, a compound represented by the following formula (As1) can be suitably used.

[0187] (In the formula, D 1 represents a naphthalene ring or an anthracene ring, D 2 represents a divalent to tetravalent perfluorobiphenyl group, j 1 is D 1 represents the number of sulfonic acid groups bonded to j, and 1≦j 1 j is an integer that satisfies the following: 2 is D 2 and the number of bonds between the oxygen atom, and is an integer between 2 and 4.)

[0188] In the present invention, examples of arylsulfonic acids that can be suitably used include compounds represented by the following formula (As1-1).

[0189]

[0190] The arylsulfonic acid represented by formula (As1) can be synthesized by a known method, for example, by the method described in WO 2006 / 025342.

[0191] When the charge-transporting composition of the present invention contains an arylsulfonic acid, the content thereof is preferably about 0.001 to 50 parts by mass, more preferably about 0.05 to 10 parts by mass, and even more preferably 0.1 to 5 parts by mass, per 1 part of the charge-transporting substance.

[0192] The ionic compound may be represented by the following formula (An1) or Z a and a metal salt or onium salt formed from an anion represented by the following formula:

[0193] (wherein E represents an element belonging to Group 13 of the long period periodic table, Ar a1 ~Ar a4 each independently represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent.

[0194] In formula (An1), E is preferably boron or gallium among elements belonging to Group 13 of the long form periodic table, and more preferably boron.

[0195] In formula (An1), examples of the aromatic hydrocarbon group and aromatic heterocyclic group include monovalent groups derived from a 5- or 6-membered monocyclic ring or 2- to 4-condensed ring. Among these, from the viewpoint of the stability and heat resistance of the compound, monovalent groups derived from a benzene ring, a naphthalene ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, a triazine ring, a quinoline ring, and an isoquinoline ring are preferred. a1 ~Ar a4 It is more preferable that at least one of the groups has one or more fluorine atoms or chlorine atoms as a substituent. a1 ~Ar a4 It is most preferably a perfluoroaryl group in which all of the hydrogen atoms are substituted with fluorine atoms. Specific examples of the perfluoroaryl group include a pentafluorophenyl group, a heptafluoro-2-naphthyl group, and a tetrafluoro-4-pyridyl group.

[0196] Z aExamples of the cation ion include an ion represented by the following formula (An2), a hydroxide ion, a fluoride ion, a chloride ion, a bromide ion, an iodide ion, a cyanide ion, a nitrate ion, a nitrite ion, a sulfate ion, a sulfite ion, a perchlorate ion, a perbromate ion, a periodate ion, a chlorate ion, a chlorite ion, a hypochlorite ion, a phosphate ion, a phosphite ion, a hypophosphite ion, a borate ion, an isocyanate ion, a hydrosulfide ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a hexachloroantimonate ion; a carboxylate ion such as an acetate ion, a trifluoroacetate ion, and a benzoate ion; a sulfonate ion such as a methanesulfonic acid ion and a trifluoromethanesulfonate ion; and an alkoxy ion such as a methoxy ion and a t-butoxy ion.

[0197] (In the formula, E 2 represents an element belonging to Group 15 of the long-form periodic table, and X n1 represents a halogen atom such as a fluorine atom, a chlorine atom, or a bromine atom.

[0198] In formula (An2), E 2 is preferably a phosphorus atom, an arsenic atom, or an antimony atom, and is preferably a phosphorus atom in terms of the stability of the compound, ease of synthesis and purification, and toxicity. n1 is preferably a fluorine atom or a chlorine atom, and most preferably a fluorine atom, from the viewpoint of the stability of the compound and ease of synthesis and purification.

[0199] On the other hand, metal ions and onium ions can be suitably used as counter cations. The metal ions are preferably monovalent metal ions, such as Li + , Na + , K. + and Ag + In particular, Ag + The onium ion may, for example, be an iodonium ion, a sulfonium ion, an ammonium ion, or a phosphonium ion, and is particularly preferably an iodonium ion represented by the following formula (Ct1):

[0200]

[0201] In formula (Ct1), R 101 and R 102 are each independently an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a heteroaryl group having 2 to 20 carbon atoms, which may be substituted with a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a heteroaryl group having 2 to 20 carbon atoms.

[0202] As the counter cation, an ion represented by the following formula (Ct1′) can also be used.

[0203]

[0204] In formula (Ct1'), A 4 represents an element in the third period or later (third to sixth periods) of the periodic table, and belonging to Group 16 of the long-form periodic table. In the present invention, among these, elements in the fifth period or earlier (third to fifth periods) of the periodic table are preferred from the viewpoint of electron-accepting properties and easy availability. That is, A 4 is preferably any one of a sulfur atom, a selenium atom and a tellurium atom, and more preferably a sulfur atom.

[0205] R 103 Is A 4 represents an organic group bonded to R via a carbon atom; 104 and R 105 R are each independently an optional substituent. 103 ~R 105 Two or more adjacent groups may be bonded to each other to form a ring.

[0206] R 103 Is A 4 The type of organic group is not particularly limited as long as it has a carbon atom at the bonding site with R. 103 The molecular weight of each of R is usually 1,000 or less, preferably 500 or less, including the value of the substituent. 103Preferred examples of the group include alkyl groups, alkenyl groups, alkynyl groups, aromatic hydrocarbon groups, and aromatic heterocyclic groups, from the viewpoint of delocalizing the positive charge. Among these, aromatic hydrocarbon groups and aromatic heterocyclic groups are preferred, as they delocalize the positive charge and are thermally stable.

[0207] Examples of aromatic hydrocarbon groups include monovalent groups derived from a 5- or 6-membered monocyclic ring or 2- to 5-fused rings, which can delocalize a positive charge on the group. Specific examples include monovalent groups derived from a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzpyrene ring, a chrysene ring, a triphenylene ring, an acenaphthene ring, and a fluorene ring. More specific examples 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. Phenyl and tolyl groups are preferred, and tolyl groups are more preferred.

[0208] Examples of aromatic heterocyclic groups include monovalent groups derived from a 5- or 6-membered monocyclic ring or 2- to 4-condensed ring, which can delocalize a positive charge on the group. Specific examples thereof include monovalent groups derived from a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, a triazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carbazole ring, a pyrroloimidazole ring, a pyrrolopyrazole ring, a pyrrolopyrrole ring, a thienopyrrole ring, a thienothiophene ring, a furopyrrole ring, a furofuran ring, a thienofuran ring, a benzisoxazole ring, a benzisothiazole ring, a benzimidazole ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, a triazine ring, a quinoline ring, an isoquinoline ring, a cinnoline ring, a quinoxaline ring, a phenanthridine ring, a benzimidazole ring, a pyrimidine ring, a quinazoline ring, a quinazolinone ring, an azulene ring, or the like.

[0209] The alkyl group may be linear, branched, or cyclic, and typically has at least 1 carbon atom and at most 12 carbon atoms, preferably at most 6 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, a 2-propyl group, an n-butyl group, an isobutyl group, a tert-butyl group, and a cyclohexyl group.

[0210] The alkenyl group includes those having a carbon number of usually 2 or more and usually 12 or less, preferably 6 or less. Specific examples include a vinyl group, an allyl group, and a 1-butenyl group.

[0211] The alkynyl group includes those having a carbon number of usually 2 or more and usually 12 or less, preferably 6 or less. Specific examples include an ethynyl group and a propargyl group.

[0212] R 104 and R 105 is not particularly limited as long as it does not contradict the spirit of the present invention. 104 and R 105 The molecular weight of each of R is usually 1,000 or less, preferably 500 or less, including the value of the substituent. 104 and R 105 Examples of R include an alkyl group, an alkenyl group, an alkynyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group, an amino group, an alkoxy group, an aryloxy group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylcarbonyloxy group, an alkylthio group, an arylthio group, a sulfonyl group, an alkylsulfonyl group, an arylsulfonyl group, a cyano group, a hydroxy group, a thiol group, and a silyl group. 103 As with A, A has a large electron-accepting property. 4 An organic group having a carbon atom at the bonding site is preferred, and examples thereof include alkyl groups, alkenyl groups, alkynyl groups, aromatic hydrocarbon groups, and aromatic heterocyclic groups. In particular, aromatic hydrocarbon groups and aromatic heterocyclic groups are preferred because of their high electron-accepting ability and thermal stability.

[0213] The alkyl group, alkenyl group, alkynyl group, aromatic hydrocarbon group, and aromatic heterocyclic group include R103 The same as those explained above can be mentioned.

[0214] Examples of the amino group include an alkylamino group, an arylamino group, and an acylamino group. Examples of the alkylamino group include an alkylamino group having one or more alkyl groups, usually having one or more carbon atoms and usually having 12 or less, preferably 6 or less. Specific examples include a methylamino group, a dimethylamino group, a diethylamino group, and a dibenzylamino group.

[0215] The arylamino group includes an arylamino group having one or more aromatic hydrocarbon groups or aromatic heterocyclic groups, each having a carbon number of usually 3 or more, preferably 4 or more, and usually 25 or less, preferably 15 or less. Specific examples include a phenylamino group, a diphenylamino group, a tolylamino group, a pyridylamino group, and a thienylamino group.

[0216] The acylamino group includes an acylamino group having one or more acyl groups, each having a carbon number of usually 2 or more and usually 25 or less, preferably 15 or less. Specific examples include an acetylamino group and a benzoylamino group.

[0217] The alkoxy group includes an alkoxy group having a carbon number of usually 1 or more and usually 12 or less, preferably 6 or less. Specific examples include a methoxy group, an ethoxy group, and a butoxy group.

[0218] The aryloxy group includes an aryloxy group having an aromatic hydrocarbon group or an aromatic heterocyclic group having a carbon number of usually 3 or more, preferably 4 or more, and usually 25 or less, preferably 15 or less. Specific examples include a phenyloxy group, a naphthyloxy group, a pyridyloxy group, and a thienyloxy group.

[0219] The acyl group includes an acyl group having a carbon number of usually 1 or more and usually 25 or less, preferably 15 or less. Specific examples include a formyl group, an acetyl group, and a benzoyl group.

[0220] The alkoxycarbonyl group includes an alkoxycarbonyl group having a carbon number of usually 2 or more and usually 10 or less, preferably 7 or less. Specific examples include a methoxycarbonyl group and an ethoxycarbonyl group.

[0221] The aryloxycarbonyl group includes an aromatic hydrocarbon group or aromatic heterocyclic group having a carbon number of usually 3 or more, preferably 4 or more, and usually 25 or less, preferably 15 or less. Specific examples include a phenoxycarbonyl group and a pyridyloxycarbonyl group.

[0222] The alkylcarbonyloxy group includes an alkylcarbonyloxy group having a carbon number of usually 2 or more and usually 10 or less, preferably 7 or less. Specific examples include an acetoxy group and a trifluoroacetoxy group.

[0223] The alkylthio group includes an alkylthio group having a carbon number of usually 1 or more and usually 12 or less, preferably 6 or less. Specific examples include a methylthio group and an ethylthio group.

[0224] The arylthio group includes an arylthio group having usually 3 or more, preferably 4 or more, carbon atoms, and usually 25 or less, preferably 14 or less. Specific examples include a phenylthio group, a naphthylthio group, and a pyridylthio group.

[0225] Specific examples of the alkylsulfonyl group and the arylsulfonyl group include a mesyl group and a tosyl group.

[0226] Specific examples of the sulfonyloxy group include a mesyloxy group and a tosyloxy group.

[0227] Specific examples of the silyl group include a trimethylsilyl group and a triphenylsilyl group.

[0228] Above, R 103 , R 104 and R 105The groups exemplified as may be further substituted with other substituents as long as it does not go against the spirit of the present invention. The type of the substituent is not particularly limited, but for example, 103 , R 104 and R 105 In addition to the groups exemplified above, examples include a halogen atom, a cyano group, a thiocyano group, a nitro group, etc. Among these, from the viewpoint of not interfering with the heat resistance and electron-accepting property of the ionic compound (electron-accepting ionic compound), an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aryloxy group, an aromatic hydrocarbon group, or an aromatic heterocyclic group is preferred.

[0229] Among the above, ionic compounds which are combinations of anions and cations represented by the following formulae (AC1) to (AC7) (see Japanese Patent No. 5381931) can be preferably used.

[0230]

[0231]

[0232] Furthermore, onium borate salts (which are electrically neutral salts) consisting of a monovalent or divalent anion represented by formula (An3) and a counter cation represented by formulas (Ct2) to (Ct6) can also be suitably used.

[0233]

[0234] In the formula, Ar each independently represents an aryl group which may have a substituent or a heteroaryl group which may have a substituent; L represents an alkylene group, —NH—, an oxygen atom, a sulfur atom, or —CN + Represents -.

[0235] Examples of the aryl group include aryl groups having 6 to 20 carbon atoms. Specific examples thereof 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.

[0236] Examples of the substituent include a halogen atom, a nitro group, a cyano group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, and an alkynyl group having 2 to 20 carbon atoms.

[0237] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, with a fluorine atom being preferred.

[0238] The alkyl group having 1 to 20 carbon atoms may be linear, branched, or cyclic. Specific examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a 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. An alkyl group having 1 to 18 carbon atoms is preferred, and an alkyl group having 1 to 8 carbon atoms is more preferred.

[0239] Specific 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.

[0240] Specific examples of alkynyl groups having 2 to 20 carbon atoms include an ethynyl group, an n-1-propynyl group, an n-2-propynyl group, an n-1-butynyl group, an n-2-butynyl group, an n-3-butynyl group, a 1-methyl-2-propynyl group, an n-1-pentynyl group, an n-2-pentynyl group, an n-3-pentynyl group, an n-4-pentynyl group, a 1-methyl-n-butynyl group, a 2-methyl-n-butynyl group, a 3-methyl-n-butynyl group, a 1,1-dimethyl-n-propynyl group, an n-1-hexynyl group, an n-1-decynyl group, an n-1-pentadecinyl group, and an n-1-eicosynyl group.

[0241] Among the above-mentioned substituents, the aryl group preferably has one or more electron-withdrawing groups, such as a halogen atom, a nitro group, and a cyano group, with a halogen atom being preferred and a fluorine atom being particularly preferred.

[0242] The heteroaryl group preferably includes a heteroaryl group having 2 to 20 carbon atoms. Specific examples thereof include oxygen-containing heteroaryl groups such as a 2-thienyl group, a 3-thienyl group, a 2-furanyl group, a 3-furanyl group, a 2-oxazolyl group, a 4-oxazolyl group, a 5-oxazolyl group, a 3-isoxazolyl group, a 4-isoxazolyl group, and a 5-isoxazolyl group; sulfur-containing heteroaryl groups such as a 2-thiazolyl group, a 4-thiazolyl group, a 5-thiazolyl group, a 3-isothiazolyl group, a 4-isothiazolyl group, and a 5-isothiazolyl group; 2-imidazolyl groups; a 4-imidazolyl group, a 2-pyridyl group, a 3-pyridyl group, a 4-pyridyl group, a 2-pyrazyl group, a 3-pyrazyl group, a 5-pyrazyl group, a 6-pyrazyl group, a 2-pyrimidyl group, a 4-pyrimidyl group, a 5-pyrimidyl group, a 6-pyrimidyl group, a 3-pyridazyl group, a 4-pyridazyl group, a 5-pyridazyl group, a 6-pyridazyl group, a 1,2,3-triazin-4-yl group, a 1,2,3-triazin-5-yl group, a 1,2,4-triazin-3-yl group, a 1,2, 4-triazin-5-yl group, 1,2,4-triazin-6-yl group, 1,3,5-triazin-2-yl group, 1,2,4,5-tetrazin-3-yl group, 1,2,3,4-tetrazin-5-yl group, 2-quinolinyl group, 3-quinolinyl group, 4-quinolinyl group, 5-quinolinyl group, 6-quinolinyl group, 7-quinolinyl group, 8-quinolinyl group, 1-isoquinolinyl group, 3-isoquinolinyl group, 4-isoquinolinyl group, 5-isoquinolinyl group, 6-isoquinolinyl group, and nitrogen-containing heteroaryl groups such as isoquinolinyl group, 7-isoquinolinyl group, 8-isoquinolinyl group, 2-quinoxanyl group, 5-quinoxanyl group, 6-quinoxanyl group, 2-quinazolinyl group, 4-quinazolinyl group, 5-quinazolinyl group, 6-quinazolinyl group, 7-quinazolinyl group, 8-quinazolinyl group, 3-cinnolinyl group, 4-cinnolinyl group, 5-cinnolinyl group, 6-cinnolinyl group, 7-cinnolinyl group, and 8-cinnolinyl group.

[0243] Examples of the substituent on the heteroaryl group include the same substituents as those exemplified for the aryl group.

[0244] L is an alkylene group, —NH—, an oxygen atom, a sulfur atom, or —CN + - represents -CN + - is preferred.

[0245] The alkylene group may be linear, branched, or cyclic, and includes an alkylene group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms. Specific examples thereof include a methylene group, a methylmethylene group, a dimethylmethylene group, an ethylene group, a trimethylene group, a propylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group.

[0246] Examples of the anion of the above formula (An3) that can be suitably used in the present invention include, but are not limited to, those represented by formula (An3-1).

[0247]

[0248] On the other hand, examples of the counter cation include those represented by formulae (Ct2) to (Ct6).

[0249]

[0250] In the present invention, the onium borate salts may be used alone or in combination of two or more. If necessary, other known onium borate salts may be used in combination. The onium borate salts may be synthesized by referring to known methods described, for example, in JP-A-2005-314682.

[0251] The onium borate salt may be dissolved in an organic solvent in advance to facilitate dissolution in the charge transport composition. Examples of such organic solvents include carbonates such as propylene carbonate, ethylene carbonate, 1,2-butylene carbonate, dimethyl carbonate, and diethyl carbonate; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, and 2-heptanone; polyhydric alcohols and derivatives thereof such as ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, dipropylene glycol, and the monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether, and monophenyl ether of dipropylene glycol monoacetate; cyclic ethers such as dioxane; and formic acid. Examples of suitable organic solvents include esters such as ethyl acetate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, methyl acetoacetate, ethyl acetoacetate, ethyl pyruvate, ethyl ethoxyacetate, methyl methoxypropionate, ethyl ethoxypropionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, methyl 2-hydroxy-3-methylbutanoate, 3-methoxybutyl acetate, and 3-methyl-3-methoxybutyl acetate; and aromatic hydrocarbons such as toluene, xylene, 3-phenoxytoluene, 4-methoxytoluene, methyl benzoate, cyclohexylbenzene, tetralin, and isophorone. These may be used alone or in combination of two or more. When an organic solvent is used, the amount used is preferably 15 to 1,000 parts by mass, and more preferably 30 to 500 parts by mass, per 100 parts by mass of the onium borate salt.

[0252] Furthermore, when the charge transport composition of the present invention contains an ionic compound, the content thereof is preferably about 0.001 to 50, more preferably about 0.05 to 10, and even more preferably about 0.1 to 5, by mass ratio relative to 1 of the charge transport substance.

[0253] Specific examples of the tetracyanoquinodimethane derivative include tetracyanoquinodimethanes such as 7,7,8,8-tetracyanoquinodimethane (TCNQ), 2-fluoro-7,7,8,8-tetracyanoquinodimethane, and 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane, and halotetracyanoquinodimethanes (haloTCNQs) such as tetrafluoro-7,7,8,8-tetracyanoquinodimethane. Specific examples of the benzoquinone derivative include tetrafluoro-1,4-benzoquinone, tetrachloro-1,4-benzoquinone (chloranil), and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). These inorganic and organic dopant substances may be used alone or in combination of two or more.

[0254] Furthermore, examples of the halotetracyanoquinodimethane compound include compounds represented by formula (Tq1).

[0255]

[0256] In the formula, R 1q ~R 4q are each independently a hydrogen atom or a halogen atom, at least one of which is a halogen atom, preferably at least two of which are halogen atoms, more preferably at least three of which are halogen atoms, and most preferably all of which are halogen atoms. Examples of halogen atoms include the same as those mentioned above, but a fluorine atom or a chlorine atom is preferred, and a fluorine atom is more preferred.

[0257] Specific examples of the halotetracyanoquinodimethane compound include tetrafluorotetracyanoquinodimethane (F4TCNQ), tetrachlorotetracyanoquinodimethane, 2-fluorotetracyanoquinodimethane, 2-chlorotetracyanoquinodimethane, 2,5-difluorotetracyanoquinodimethane, and 2,5-dichlorotetracyanoquinodimethane, with F4TCNQ being most suitable in the present invention.

[0258] When the charge-transporting composition of the present invention contains a halotetracyanoquinodimethane compound, the content thereof is preferably about 0.001 to 50, more preferably about 0.05 to 10, and even more preferably about 0.1 to 5, by mass ratio relative to 1 of the charge-transporting substance.

[0259] [Organosilane Compound] The charge transport composition of the present invention may contain an organosilane compound in order to improve the stability of the resulting photoelectric conversion element.

[0260] As the organic silane compound, alkoxysilanes are preferred, with trialkoxysilanes and tetraalkoxysilanes being more preferred. Examples of the alkoxysilane include tetraethoxysilane (TEOS), tetramethoxysilane, tetraisopropoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, dimethyldiethoxysilane, and dimethyldimethoxysilane. Among these, TEOS, tetramethoxysilane, and tetraisopropoxysilane are preferred for use in the present invention. These organic silane compounds can be used alone or in combination of two or more.

[0261] The content of the organosilane compound is preferably 0.1 to 10 times, more preferably 0.5 to 7 times, and even more preferably 1.0 to 5 times, the amount of the charge transporting substance, or, when an electron-accepting dopant substance is included, the amount of the charge transporting substance and the electron-accepting dopant substance combined, in parts by mass. By setting the amount of the organosilane compound in the above range, the stability of the resulting photoelectric conversion element can be improved.

[0262] The composition of the present invention may contain other additives as long as the object of the present invention can be achieved. The type of additive can be appropriately selected from known additives depending on the desired effect.

[0263] The solids concentration of the charge-transporting composition of the present invention is appropriately set taking into consideration the viscosity and surface tension of the composition, the thickness of the thin film to be formed, etc., but is usually preferably about 0.1 to 20.0 mass %, more preferably 0.5 to 10.0 mass %, and even more preferably 1.0 to 5.0 mass %. Note that the solids in the solids concentration here refer to the components other than the solvent contained in the charge-transporting composition of the present invention.

[0264] The viscosity of the charge transporting composition of the present invention is adjusted appropriately depending on the coating method, taking into consideration the thickness of the thin film to be produced and the solid content concentration, but is usually about 0.1 to 50 mPa·s at 25°C.

[0265] [Preparation of Charge-Transporting Composition] The charge-transporting composition of the present invention can be prepared by mixing a charge-transporting substance, an electron-accepting dopant substance, an organic solvent, and, if necessary, an organosilane compound and other additives in any order, as long as the solid content is uniformly dissolved or dispersed in the solvent. That is, for example, a method of dissolving a specific polymer as a charge-transporting substance in an organic solvent and then dissolving an electron-accepting dopant substance in the solution, a method of dissolving an electron-accepting dopant substance in an organic solvent and then dissolving a specific polymer in the solution, or a method of mixing a specific polymer and an electron-accepting dopant substance and then introducing the mixture into a solvent and dissolving the mixture can all be employed, as long as the solid content is uniformly dissolved or dispersed in the solvent.

[0266] In addition, the preparation of the charge transporting composition is usually carried out in an inert gas atmosphere at room temperature and normal pressure, but it may also be carried out in an air atmosphere (in the presence of oxygen) or while heating, as long as the compounds in the composition are not decomposed or the composition is not significantly changed.

[0267] [Charge Transport Thin Film] The charge transport composition described above can be suitably used to form a charge transport thin film in an organic photoelectric conversion element. It is particularly preferred when the organic photoelectric conversion element is a perovskite photoelectric conversion element, and the charge transport composition is more effective when used as a hole collection layer in the perovskite photoelectric conversion element. Perovskite solar cells equipped with a perovskite photoelectric conversion element are either normal stacking type or reverse stacking type. The hole collection layer of the present invention can be formed by applying the charge transport composition of the present invention to the active layer in the case of a normal stacking type perovskite solar cell, or to the anode in the case of a reverse stacking type perovskite solar cell, followed by baking. From the viewpoint of the solvent resistance of the resulting charge transport thin film, the reverse stacking type is a preferred embodiment of the present invention. For coating, an optimum method may be selected from various wet processes such as drop casting, spin coating, blade coating, dip coating, roll coating, bar coating, die coating, inkjet printing, printing (relief printing, intaglio printing, lithography, screen printing, etc.), taking into consideration the viscosity and surface tension of the composition, the desired thickness of the thin film, etc. Coating is usually carried out in an inert gas atmosphere at room temperature and normal pressure, but may also be carried out in the air (in the presence of oxygen) or while heating, as long as the compounds in the composition are not decomposed or the composition does not change significantly.

[0268] The film thickness is not particularly limited, but in any case, it is preferably about 0.1 to 500 nm, more preferably about 1 to 100 nm. Methods for changing the film thickness include changing the solid concentration in the composition or changing the amount of solution at the time of application.

[0269] [Perovskite Solar Cell] Hereinafter, a method for manufacturing a perovskite solar cell using the charge-transporting composition of the present invention as a composition for forming a hole-collecting layer will be described, but the present invention is not limited thereto. (1) Inverted Stacked Perovskite Solar Cell [Formation of Anode Layer]: A step of forming a layer of anode material on the surface of a transparent substrate to produce a transparent electrode. Examples of anode materials that can be used include inorganic oxides such as indium tin oxide (ITO) and indium zinc oxide (IZO), metals such as gold, silver, and aluminum, and highly charge-transporting organic compounds such as polythiophene derivatives and polyaniline derivatives. Among these, ITO is most preferred. Furthermore, a substrate made of glass or transparent resin can be used as the transparent substrate. The method for forming the anode material layer (anode layer) is appropriately selected depending on the properties of the anode material. Typically, dry processes such as vacuum deposition and sputtering are selected for poorly soluble or poorly dispersible sublimable materials. For solution or dispersion materials, the optimal wet process is selected from the various methods described above, taking into consideration the viscosity and surface tension of the composition, the desired thin film thickness, and other factors.

[0270] Alternatively, a commercially available transparent anode substrate can be used. In this case, it is preferable to use a substrate that has been subjected to a smoothing treatment in order to improve the yield of the device. When a commercially available transparent anode substrate is used, the method for producing a perovskite solar cell of the present invention does not include a step of forming an anode layer. When forming a transparent anode substrate using an inorganic oxide such as ITO as the anode material, it is preferable to wash the substrate with detergent, alcohol, pure water, or the like before laminating an upper layer. Furthermore, it is preferable to perform a surface treatment such as UV ozone treatment or oxygen-plasma treatment immediately before use. When the anode material is mainly composed of an organic substance, surface treatment may not be necessary.

[0271] [Formation of hole-collecting layer]: Step of forming a hole-collecting layer on the formed layer of anode material According to the method described above, a hole-collecting layer is formed on the layer of anode material using the charge-transporting composition of the present invention.

[0272] [Formation of Active Layer]: Step of forming an active layer on the formed hole collection layer In the present invention, an active layer containing a perovskite semiconductor compound is used as the active layer. The perovskite semiconductor compound refers to a semiconductor compound having a perovskite structure. As the perovskite semiconductor compound, known compounds can be used, and are not particularly limited. For example, a compound represented by the general formula A + M 2+ X - 3, or the general formula A + 2M 2+ X - 4, where A + represents a monovalent cation, M 2+ represents a divalent cation, and X - represents a monovalent anion.

[0273] Monovalent cation A + Examples of the cation include cations containing elements of Groups 1 and 13 to 16 of the periodic table. Among these, cesium ions, rubidium ions, ammonium ions which may have a substituent, and phosphonium ions which may have a substituent are preferred.

[0274] Examples of ammonium ions that may have a substituent include primary ammonium ions and secondary ammonium ions. There are no particular restrictions on the substituent, but alkylammonium ions or arylammonium ions are preferred. In particular, monoalkylammonium ions that form a three-dimensional crystal structure are more preferred to avoid steric hindrance. The number of carbon atoms in the alkyl group contained in the alkylammonium ion is preferably 1 to 30, more preferably 1 to 20, and even more preferably 1 to 10. The number of carbon atoms in the aryl group contained in the arylammonium ion is preferably 6 to 30, more preferably 6 to 20, and even more preferably 6 to 12.

[0275] Monovalent cation A +Specific examples of the cation A include a methylammonium ion, an ethylammonium ion, an isopropylammonium ion, an n-propylammonium ion, an isobutylammonium ion, an n-butylammonium ion, a t-butylammonium ion, a dimethylammonium ion, a diethylammonium ion, a phenylammonium ion, a benzylammonium ion, a phenethylammonium ion, a guanidium ion, a formamidinium ion, an acetamidinium ion, and an imidazolium ion. + can be used alone or in combination of two or more.

[0276] Divalent cation M 2+ As the divalent cation M, a divalent metal cation or a semimetal cation is preferred, and a cation of an element of Group 14 of the periodic table is more preferred. Specific examples of the divalent cation M include lead cation (Pb 2+ ), tin cations (Sn 2+ ), germanium cation (Ge 2+ In the present invention, it is preferable to contain lead cations from the viewpoint of obtaining a photoelectric conversion element having excellent stability. 2+ can be used alone or in combination of two or more.

[0277] Monovalent anion X - Examples of the anion X include halide ions, acetate ions, nitrate ions, acetylacetonate ions, thiocyanate ions, and 2,4-pentanedionate ions, with halide ions being preferred. - can be used alone or in combination of two or more.

[0278] Examples of halide ions include chloride ions, bromide ions, iodide ions, etc. In the present invention, it is preferable to contain iodide ions from the viewpoint of preventing the band gap of the semiconductor from becoming too wide.

[0279] As the perovskite semiconductor compound, for example, an organic-inorganic perovskite semiconductor compound is preferable, and a halide-based organic-inorganic perovskite semiconductor compound is more preferable. Specific examples of the perovskite semiconductor compound include MAPbI3, MAPbBr3, MAPbCl3, MASnI3, MASnBr3, MASnCl3, and MAPbI (3-x) Cl x , MAPbI (3-x) Br x , MAPbBr (3-x) Cl x , MAPb (1-y) Sn y I3, MAPb (1-y) Sn y Br3, MAPb (1-y) Sn y Cl3, MAPb (1-y) Sn y I (3-x) Cl x , MAPb (1-y) Sn y I (3-x) Br x , MAPb (1-y) Sn y Br (3-x) Cl x , FAPbI3, FAPbBr3, FAPbI (3-x) Br x , F.A. (1-V) MA V PbI (3-x) Br x , Cs (1-W-V) FA w MA V PbI (3-x) Br x In addition, MA is methylammonium (CH3NH3 + ) and FA represents formamidinium (NH=CHNH + ) where x is an arbitrary number from 0 to 3 and y is an arbitrary number from 0 to 1.

[0280] From the viewpoint of improving photoelectric conversion efficiency, it is preferable to use a semiconductor compound having an energy band gap of 1.0 to 3.5 eV as the perovskite semiconductor compound.

[0281] The active layer may contain two or more types of perovskite semiconductor compounds. + , M 2+ and X - The active layer may contain two or more types of perovskite semiconductor compounds, at least one of which is different.

[0282] From the viewpoint of obtaining good photoelectric conversion characteristics, the content of the perovskite semiconductor compound in the active layer is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more. There is no particular upper limit, but it is usually 100% by mass or less.

[0283] Similarly to the above, the active layer is formed by selecting the most suitable method from the various wet processes described above, taking into consideration the viscosity and surface tension of the composition, the desired thickness of the thin film, and the like.

[0284] [Formation of Electron Collecting Layer]: A step of forming an electron collecting layer on the formed active layer. If necessary, an electron collecting layer may be formed between the active layer and the cathode layer for the purpose of improving the efficiency of charge transfer, etc. Materials for forming the electron collecting layer include fullerenes, lithium oxide (LiO), magnesium oxide (MgO), alumina (AlO), lithium fluoride (LiF), sodium fluoride (NaF), magnesium fluoride (MgF), strontium fluoride (SrF), cesium carbonate (CsCO), 8-quinolinol lithium salt (Liq), 8-quinolinol sodium salt (Naq), bathocuproine (BCP), 4,7-diphenyl-1,10-phenanthroline (BPhen), polyethyleneimine (PEI), and ethoxylated polyethyleneimine (PEIE).

[0285] As fullerenes, fullerene and its derivatives are preferred, but are not particularly limited. Specific examples include fullerenes and their derivatives having a basic skeleton of C60, C70, C76, C78, ​​C84, etc. In the fullerene derivative, the carbon atoms in the fullerene skeleton may be modified with any functional group, and these functional groups may be bonded to each other to form a ring. The fullerene derivative includes a fullerene-bonded polymer. A fullerene derivative having a functional group with high affinity for a solvent and high solubility in the solvent is preferred.

[0286] Examples of functional groups in fullerene derivatives include hydrogen atoms, hydroxy groups, halogen atoms such as fluorine atoms and chlorine atoms, alkyl groups such as methyl groups and ethyl groups, alkenyl groups such as vinyl groups, alkoxy groups such as cyano groups, methoxy groups and ethoxy groups, aromatic hydrocarbon groups such as phenyl groups and naphthyl groups, and aromatic heterocyclic groups such as thienyl groups and pyridyl groups. Specific examples include hydrogenated fullerenes such as C60H36 and C70H36, oxide fullerenes such as C60 and C70, and fullerene metal complexes. It is more preferable to use [6,6]-phenyl C61 butyric acid methyl ester (

[60] PCBM) or [6,6]-phenyl C71 butyric acid methyl ester (

[70] PCBM) as the fullerene derivative.

[0287] Similarly to the above, when the electron-collecting material is a poorly soluble sublimable material, the various dry processes described above are selected as the method for forming the electron-collecting layer. When the electron-collecting material is a solution material or a dispersion material, the viscosity and surface tension of the composition, the desired thickness of the thin film, and the like are taken into consideration, and the optimum method is selected from the various wet processes described above.

[0288] [Cathode Layer Formation]: A step of forming a cathode layer on the formed electron collection layer. Cathode materials include metals such as aluminum, magnesium-silver alloys, aluminum-lithium alloys, lithium, sodium, potassium, cesium, calcium, barium, silver, and gold; inorganic oxides such as indium tin oxide (ITO) and indium zinc oxide (IZO); and high-charge-transport organic compounds such as polythiophene derivatives and polyaniline derivatives. Multiple cathode materials can be stacked or mixed for use. Similarly to the above, when the cathode layer material is a poorly soluble or poorly dispersible sublimable material, the various dry processes described above are selected. When the cathode layer material is a solution or dispersion material, the viscosity and surface tension of the composition, the desired thin film thickness, and other factors are taken into consideration, and an optimal method is selected from the various wet processes described above.

[0289] [Formation of Carrier Blocking Layer] If necessary, a carrier blocking layer may be provided between any layers for the purpose of controlling the rectification of photocurrent, etc. When a carrier blocking layer is provided, an electron blocking layer is typically inserted between the active layer and the hole collecting layer or the anode, and a hole blocking layer is inserted between the active layer and the electron collecting layer or the cathode, but this is not limited thereto. Examples of materials for forming the hole blocking layer include titanium oxide, zinc oxide, tin oxide, bathocuproine (BCP), and 4,7-diphenyl-1,10-phenanthroline (BPhen). Examples of materials for forming the electron blocking layer include triarylamine-based materials such as N,N'-di(1-naphthyl)-N,N'-diphenylbenzidine (α-NPD) and poly(triarylamine) (PTAA).

[0290] Similarly, when the carrier block layer material is a poorly soluble or poorly dispersible sublimable material, the various dry processes described above are selected as the method for forming the carrier block layer. When the carrier block layer material is a solution material or dispersion material, the optimum method is selected from the various wet process methods described above, taking into consideration the viscosity and surface tension of the composition, the desired thin film thickness, etc.

[0291] (2) Forward-Layered Perovskite Solar Cell [Cathode Layer Formation]: A Step of Forming a Cathode Material Layer on the Surface of a Transparent Substrate to Produce a Transparent Cathode Substrate. Cathode materials include those exemplified for the reverse-layered anode material described above, as well as fluorine-doped tin oxide (FTO). Transparent substrates include those exemplified for the reverse-layered anode material described above. Regarding the method of forming the cathode material layer (cathode layer), the dry process described above is selected for poorly soluble or poorly dispersible sublimable materials. For solution or dispersion materials, an optimal method is selected from the various wet processes described above, taking into consideration the viscosity and surface tension of the composition, the desired thin film thickness, and other factors. In this case, commercially available transparent cathode substrates can also be used. From the viewpoint of improving device yield, it is preferable to use a substrate that has been smoothed. When using a commercially available transparent cathode substrate, the manufacturing method of the perovskite solar cell of the present invention does not include a step of forming a cathode layer. When forming a transparent cathode substrate using an inorganic oxide as the cathode material, cleaning and surface treatment similar to those for the reverse-layered anode material may be performed.

[0292] [Formation of Electron Collecting Layer]: Step of Forming an Electron Collecting Layer on the Formed Cathode If necessary, an electron collecting layer may be formed between the active layer and the cathode layer for purposes such as improving the efficiency of charge transfer. Materials for forming the electron collecting layer include those exemplified as the inverse stacking type materials above, as well as zinc oxide (ZnO), titanium oxide (TiO), tin oxide (SnO), etc. Regarding the method for forming the electron collecting layer, the dry process described above is selected for the case of a poorly soluble or poorly dispersible sublimable material. For a solution or dispersion material, the optimum method is selected from the various wet processes described above, taking into consideration the viscosity and surface tension of the composition, the desired thin film thickness, etc. Alternatively, a method can be used in which an inorganic oxide precursor layer is formed on the cathode using a wet process (particularly a spin coating method or a slit coating method), and then baked to form an inorganic oxide layer.

[0293] [Formation of active layer]: Step of forming an active layer on the formed electron-collecting layer An active layer containing the perovskite semiconductor compound described above is formed as the active layer. The method of forming the active layer is also the same as the method described for the inverted stack type active layer above.

[0294] [Formation of hole-collecting layer]: Step of forming a hole-collecting layer on the layer of active layer material formed According to the method described above, a hole-collecting layer is formed on the layer of active layer material using the composition of the present invention.

[0295] [Formation of anode layer]: A step of forming an anode layer on the formed hole collection layer. Examples of the anode material include the same anode materials as those of the above-mentioned reverse stack type, and the method of forming the anode layer is also the same as that of the reverse stack type cathode layer.

[0296] [Formation of Carrier Blocking Layer] As in the inverted stacking type element, a carrier blocking layer may be provided between any layers as needed for the purpose of controlling the rectification of photocurrent, etc. Materials for forming the hole blocking layer and the electron blocking layer include those similar to those described above, and the method for forming the carrier blocking layer is also similar to that described above.

[0297] To prevent element degradation due to the atmosphere, perovskite solar cell elements produced by the methods exemplified above can be placed back into a glove box and sealed in an inert gas atmosphere such as nitrogen, and in this sealed state can function as solar cells or their solar cell characteristics can be measured. Examples of sealing methods include attaching a concave glass substrate with a UV-curable resin attached to its edge to the film-forming surface of the perovskite solar cell element in an inert gas atmosphere and curing the resin by UV irradiation, or performing film-sealing by techniques such as sputtering in a vacuum.

[0298] EXAMPLES 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.

[0299] The abbreviations used in the preparation of the charge transporting composition are as follows: <Tetracarboxylic acid dianhydride> Tetracarboxylic acid dianhydrides represented by the following formulae MS-1 to MS-5 <Diamine> Diamine compounds represented by the following formulae DA-1 to DA-4 <Solvent> NEP: N-ethyl-2-pyrrolidone BCS: Butyl cellosolve (ethylene glycol monobutyl ether) <Crosslinking agent> Crosslinking agents represented by the following formulae CL-1 to CL-7

[0300] The conditions for measuring the molecular weight of the polyimide precursor (polyamic acid) are as follows. Apparatus: Room temperature gel permeation chromatography (GPC) apparatus (SSC-7200) manufactured by Senshu Scientific Co., Ltd. Column: Shodex column (KD-803, KD-805) Column temperature: 50°C Eluent: N,N'-dimethylformamide (additives: lithium bromide hydrate (LiBr.HO) 30 mmol / L, phosphoric acid anhydrous crystal (o-phosphoric acid) 30 mmol / L, tetrahydrofuran (THF) 10 ml / L) Flow rate: 1.0 ml / min Standard samples for creating a calibration curve: TSK standard polyethylene oxide (molecular weights: approximately 900,000, 150,000, 100,000, 30,000) manufactured by Tosoh Corporation, and polyethylene glycol (molecular weights: approximately 12,000, 4,000, 1,000) manufactured by Polymer Laboratory Co., Ltd.

[0301] The viscosity of the polyimide precursor solution (polyamic acid solution) was measured under the following conditions: using an E-type viscometer TVE-22H (manufactured by Toki Sangyo Co., Ltd.), a sample volume of 1.1 mL, a cone rotor TE-1 (1°34', R24), and a temperature of 25°C.

[0302] <Preparation of Polyamic Acid Solution> [Synthesis Example 1] MS-1 (3.36 g, 13.4 mmol) and DA-1 (6.63 g, 14 mmol) were dissolved in NEP (89.94 g) and reacted at 40° C. for 20 hours to obtain polyamic acid solution (A1). The viscosity of the obtained polyamic acid solution was 72 mPa s, and the number average molecular weight of this polyamic acid was 9,500 and the weight average molecular weight was 42,300.

[0303] Synthesis Example 2: MS-1 (3.53 g, 14.1 mmol) and DA-2 (6.32 g, 15 mmol) were dissolved in NEP (88.66 g) and reacted at 40° C. for 20 hours to obtain a polyamic acid solution (A2). The viscosity of the obtained polyamic acid solution was 101 mPa s, and the number-average molecular weight of this polyamic acid was 10,100 and the weight-average molecular weight was 52,200.

[0304] Synthesis Example 3: MS-1 (4.71 g, 18.8 mmol) and DA-3 (3.98 g, 20 mmol) were dissolved in NEP (78.2 g) and reacted at 40° C. for 24 hours to obtain a polyamic acid solution (A3). The viscosity of the obtained polyamic acid solution was 86.3 mPa s, and the number-average molecular weight of this polyamic acid was 10,120 and the weight-average molecular weight was 26,357.

[0305] Synthesis Example 4 MS-2 (9.41 g, 47.51 mmol) and DA-3 (9.96 g, 50 mmol) were dissolved in NEP (77.50 g) and reacted at 25° C. for 6 hours to obtain a polyamic acid solution (A4). The viscosity of the obtained polyamic acid solution was 1,350 mPa s, and the number-average molecular weight of this polyamic acid was 7,831 and the weight-average molecular weight was 16,975.

[0306] Synthesis Example 5: MS-3 (3.61 g, 18.4 mmol) and DA-3 (3.99 g, 20 mmol) were dissolved in NEP (87.32 g) and reacted at 25° C. for 4 hours to obtain a polyamic acid solution (A5). The viscosity of the obtained polyamic acid solution was 56.5 mPa s, and the number-average molecular weight of this polyamic acid was 7,984 and the weight-average molecular weight was 20,233.

[0307] Synthesis Example 6: MS-4 (4.01 g, 18.4 mmol) and DA-3 (3.99 g, 20 mmol) were dissolved in NEP (91.98 g) and reacted at 25° C. for 6 hours to obtain a polyamic acid solution (A6). The viscosity of the obtained polyamic acid solution was 80.4 mPa s, and the number-average molecular weight of this polyamic acid was 7,631 and the weight-average molecular weight was 16,587.

[0308] Synthesis Example 7: MS-5 (4.42 g, 14.1 mmol) and DA-3 (2.99 g, 15 mmol) were dissolved in NEP (83.60 g) and reacted at 25° C. for 6 hours to obtain a polyamic acid solution (A7). The viscosity of the obtained polyamic acid solution was 29.7 mPa s, and the number-average molecular weight of this polyamic acid was 5,240 and the weight-average molecular weight was 10,625.

[0309] Synthesis Example 8: MS-1 (4.70 g, 16.3 mmol) and DA-4 (4.27 g, 20 mmol) were dissolved in NEP (80.73 g) and reacted at 40° C. for 24 hours to obtain a polyamic acid solution (A8). The viscosity of the obtained polyamic acid solution was 100 mPa s, and the number-average molecular weight of this polyamic acid was 9,442 and the weight-average molecular weight was 38,736.

[0310] <Preparation of Charge-Transporting Composition> [Example 1-1a] 6.0 g of NEP and 2.0 g of BCS were added to 2.0 g of the polyamic acid solution (A1) obtained in Synthesis Example 1, and the mixture was stirred at 25°C for 1 hour to obtain Solution 1. Separately, 200 mg of CL-1 was dissolved in a mixed solvent of 7.8 g of NEP and 2.0 g of BCS to obtain Solution 2. Solutions 1 and 2 were mixed so that the mass ratio of DP-1 to charge-transporting substance 1 was 0.03, and the mixture was filtered through a syringe filter with a pore size of 0.45 μm to obtain Charge-Transporting Composition (B1a) having a polyamic acid concentration of 2.0 mass%.

[0311] [Examples 1-1b to 1-1d] Charge-transporting compositions (B1b), (B1c), and (B1d) were obtained in the same manner as in Example 1-1a, except that the mass ratio of the crosslinking agent was changed to 0.05, 0.08, and 0.1, respectively. The concentration of polyamic acid in each charge-transporting composition was adjusted to 2.0 mass%.

[0312] [Example 1-2a] Charge-transporting compositions (B2a) were obtained in the same manner as in Example 1-1a, except that the crosslinking agent CL-1 was changed to CL-2. The concentration of polyamic acid in each charge-transporting composition was adjusted to 2.0% by mass.

[0313] [Examples 1-2b to 1-7d] Charge-transporting compositions (B2b) to (B7d) were obtained in the same manner as in Example 1-1a, except that the type and mass ratio of the crosslinking agent were changed based on the formulations shown in Table 1. The concentration of polyamic acid in each charge-transporting composition was adjusted to 2.0 mass%.

[0314] Comparative Example 1 6 g of NEP and 2 g of BCS were added to 2 g of the polyamic acid solution (A1) obtained in Synthesis Example 1, and the mixture was stirred for 1 hour at 25° C. The mixture was filtered through a syringe filter having a pore size of 0.45 μm to obtain a charge-transporting composition (C1) having a polyamic acid concentration of 2.0 mass %.

[0315] Comparative Examples 2 to 8 Charge-transporting compositions (C2) to (C8) were obtained in the same manner as in Comparative Example 1, except that the polyamic acid solution (A1) was changed to the polyamic acid solutions (A2) to (A8) obtained in Synthesis Examples 2 to 8, respectively.

[0316] Table 1 below summarizes the ink compositions of charge transporting compositions (B1a) to (B7d) and charge transporting compositions (C1) to (C8).

[0317]

[0318] <Solvent Resistance Test> The following equipment was used. (1) Microprofile Measuring Instrument: Surfcorder ET4000A, manufactured by Kosaka Laboratory Co., Ltd. [Example 2-1a] A glass substrate was subjected to UV / ozone treatment for 15 minutes. The charge transport composition B1a prepared in Example 1-1a was dripped onto this substrate and applied by spin coating (SC). A hole collection layer was formed by heating on a hot plate at a predetermined temperature for 10 minutes. 50 μL of N,N-dimethylformamide (DMF) was dripped onto this substrate, and after leaving it to stand for 10 seconds, it was subjected to SC at 2000 rpm for 20 seconds. The substrate was dried on a hot plate at 100°C for 10 minutes. A solvent resistance test of the hole collection layer was performed by comparing the film thickness before and after dripping DMF using the microprofile measuring instrument.

[0319] [Examples 2-1b to 2-7d, Comparative Examples 9 to 16] The solvent resistance test of the hole-collecting layer was carried out in the same manner as in Example 2-1a, except that the charge-transporting composition B1a was changed to charge-transporting compositions B1b to B7d and charge-transporting compositions C1 to C8, respectively.

[0320] The results of the solvent resistance test are summarized in Table 2 below. The film remaining rate in Table 2 was calculated using the following formula: Film remaining rate [%] = Film thickness [nm] before DMF addition / Film thickness [nm] after DMF addition × 100. Note that when the film thickness after DMF addition was 5 nm or less, it was difficult to measure, so the film remaining rate was set to 10% or less.

[0321]

[0322] The results in Table 2 confirmed the following. Note that solvent resistance is considered to be achieved when the residual film rate is 90% or higher. - Adding crosslinkers CL-1 to CL-7 at a mass ratio of 0.1 to polyamic acid and heating at 200°C or higher achieved solvent resistance to DMF. - The addition effect was particularly large with epoxy-based crosslinkers, and CL-1 to CL-3 demonstrated high solvent resistance even at a mass ratio of 0.03 and heating at 100°C.

[0323] <Preparation of Organic Photoelectric Conversion Element> The following equipment was used: (1) Glove box: VAC glove box system manufactured by Yamahachi Bussan Co., Ltd. (2) Vapor deposition apparatus: vacuum vapor deposition apparatus manufactured by Aoyama Engineering Co., Ltd. (3) Solar simulator: OTENTOSUN-III manufactured by Bunkoukeiki Co., Ltd., AM1.5G filter, radiant intensity: 100 mW / cm 2 (4) Source measure unit: Keithley Instruments, Inc., 2612A

[0324] <Preparation of Active Layer Precursor Liquid> [Preparation Example 1] 504 mg of formamidinium iodide, 65 mg of methylammonium bromide, 1,487 mg of lead(II) iodide, and 214 mg of lead(II) bromide were added to a vial in a glove box. Next, 2,346 μL of dimethyl sulfoxide (DMSO) and 586 μL of N,N-dimethylformamide were added, and the mixture was heated and stirred at 70°C for 15 minutes to dissolve the solution. Furthermore, 134 μL of a cesium iodide solution dissolved in DMSO to a concentration of 1.5 mol / L was added to prepare active layer precursor liquid 1.

[0325] <Preparation of Coating Solution for Electron Collection Layer> [Preparation Example 2] [6,6]-phenyl-C 61 150 mg of methyl acetate (manufactured by Frontier Carbon Co., Ltd.) was added, followed by adding 5,000 μL of chlorobenzene and stirring for 15 minutes to prepare coating liquid 1 for charge collection layer.

[0326] Preparation Example 3 2.5 mg of bathocuproine (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to a vial, and 5,000 μL of 2-propanol (manufactured by Kanto Chemical Co., Ltd.) was further added, followed by stirring for 1 hour to prepare coating liquid 2 for charge collection layer.

[0327] <Fabrication of Photoelectric Conversion Element> [Example 3-1a] A 25 mm x 25 mm glass substrate on which an ITO transparent conductive layer serving as an anode was patterned into 10 mm x 25 mm stripes was subjected to UV / ozone treatment for 15 minutes. Charge transport composition B1a prepared in Example 1-1a was dripped onto this substrate and applied by spin coating (SC). A hole-collecting layer was formed by heating on a hot plate at 120°C for 10 minutes. The thickness of the hole-collecting layer was approximately 5 nm. The substrate was introduced into a glove box, and active layer precursor liquid 1 obtained in Preparation Example 1 was dripped onto the formed hole-collecting layer and applied by SC. Chlorobenzene was dripped onto the substrate in SC. The resulting substrate was heated on a hot plate at 105°C for 30 minutes to form an active layer. The thickness of the active layer was approximately 400 nm. Electron-collecting layer coating liquid 1 obtained in Preparation Example 2 was applied onto the formed active layer by SC. The substrate was heated at 100°C for 10 minutes on a hot plate. Furthermore, the electron-collecting layer coating liquid 2 obtained in Preparation Example 3 was applied to the substrate by SC to form an electron-collecting layer. The layer obtained from the electron-collecting layer coating liquid 1 had a thickness of approximately 30 nm, and the layer obtained from the electron-collecting layer coating liquid 2 had a thickness of approximately 8 nm. Finally, the substrate on which the above layers were laminated was placed in a vacuum deposition apparatus, and the vacuum level in the apparatus was adjusted to 1 x 10 -3 The chamber was evacuated to a pressure of 100 Pa or less, and a silver layer serving as a cathode was evaporated to a thickness of 100 nm using a resistance heating method, thereby producing a photoelectric conversion element D1a having an area of ​​8 mm x 3 mm where the striped ITO layer and silver layer intersect.

[0328] [Examples 3-1b to 3-1d, Comparative Example 17] Photoelectric conversion elements D1b to D1d and photoelectric conversion element E1 were obtained in the same manner as in Example 3-1a, except that charge transport composition B1a was changed to charge transport compositions B1b to B1d and charge transport composition C1.

[0329] Table 3 below summarizes the photoelectric conversion elements D1a to D1d and the photoelectric conversion element E1 and the charge transporting compositions used.

[0330] <Evaluation of Device Characteristics> The photoelectric conversion devices D1a to D1d and E1 fabricated above were evaluated for short-circuit current density (Jsc [mA / cm 2The open circuit voltage (Voc [V]), fill factor (FF), and conversion efficiency (PCE [%]) were measured. PCE [%] was calculated using the following formula: PCE [%] = Jsc [mA / cm 2 ] × Voc [V] × FF ÷ Incident light intensity (100 [mW / cm 2 ) × 100 Three photoelectric conversion elements were fabricated based on the fabrication method of each example, and the maximum PCE (PCE Max ) and minimum PCE (PCE min The ratio of PCE was calculated. min / PCE Max The value of PCE is expressed as follows: 50% or less: ×, 51% to 70%: △, 71% to 90%: ◯, 91% or more: ◎. Max and PCE min / PCE Max Summarize.

[0331]

[0332] From the results in Table 3, the following was confirmed: The PCE of the photoelectric conversion element was maintained even when a crosslinking agent was added in a mass ratio of 0.03 to 0.1 relative to the polyamic acid. min / PCE Max From the comparison, it was found that the addition of a cross-linking agent stabilizes the quality of the photoelectric conversion element. This can be attributed to the fact that the addition of a cross-linking agent provides solvent resistance to the solvent used in forming the active layer, preventing the film thickness of the hole-collecting layer from changing.

Claims

1. A charge transport composition for forming a charge transport thin film in an organic photoelectric conversion element, comprising a charge transport substance, a crosslinking agent, and an organic solvent, wherein the charge transport substance comprises at least one polyimide polymer selected from the group consisting of a polyimide precursor obtained from a diamine component having a structure represented by any one of the following formulas (1) to (3) and a tetracarboxylic acid component, an ester of the polyimide precursor, and an imidized product of the polyimide precursor: (In the formula, R 1 represents a hydrogen atom or a monovalent organic group. * represents a bonding site to another group. Any hydrogen atom forming a benzene ring may be substituted with a monovalent organic group.

2. The charge transporting composition according to claim 1, wherein the crosslinking agent is at least one compound selected from the group consisting of compounds having two or more of at least one type of partial structure selected from the group consisting of partial structures represented by the following formulas (b1) to (b2), compounds having two or more epoxy groups, compounds having two or more oxetane rings, and compounds having two or more oxazoline rings. [In formula (b1), R b1 and R b1' are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or *b4-CH2-O-R b11 represents R b11 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and *b4 represents R b1 and R b1' represents a bond to the carbon atom to which it is bonded, and R b2 and R b2' each independently represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, n1 represents 0 or 1, and *b1 and *b2 represent a bond. b represents an (n2+n3+1)-valent aromatic ring, R b3 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and when n3 is 0, R b3 At least one of represents a hydrogen atom, n2 represents an integer of 1 to 6, n3 represents an integer of 0 to 6, and *b3 represents a bond.

3. The crosslinking agent is represented by the following formulae (B1-1), (B1-2), (B1-3), (B2-1) and (B E 3. The charge transporting composition according to claim 2, wherein the charge transporting composition is at least one selected from the group consisting of: [In formula (B1-1), A b represents an organic group having a valence of nx; R b4 each independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a partial structure represented by the following formula (b1-1), nx represents an integer of 2 to 6, R b1 、 R b2 、 R b1’ and R b2’ In formulas (B1-2) and (B1-3), R b5 and R b6 each independently represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a partial structure represented by the following formula (b1-1), or a partial structure represented by the following formula (b1-2), and a plurality of R b5 At least two of R represent a partial structure represented by the following formula (b1-1) or a partial structure represented by the following formula (b1-2), b6 At least two of the following represent a partial structure represented by formula (b1-1): b3 , n2 and n3 have the same meaning as above, and when at least one of n2 is 0, R b3 At least one of represents a hydrogen atom, and Y b represents an aromatic ring, any hydrogen atom of which may be substituted with an alkyl group having 1 to 3 carbon atoms, a halogen atom, an alkoxy group having 1 to 3 carbon atoms, or a vinyl group; Z b represents a single bond, a saturated hydrocarbon group having 1 to 10 carbon atoms, -NR Z -or-P 1 -Q 1 -P 2 -, and the R Z represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and 1 and P 2 each independently represents an alkyl group having 1 to 5 carbon atoms, and 1 represents an aromatic ring, the saturated hydrocarbon groups may be bonded together in whole or in part to form a cyclic structure, any hydrogen atom may be substituted with a fluorine atom, and ny represents an integer of 2 to 6. E ) Medium, R E is a divalent organic group having an aromatic ring or a cyclohexane ring and having 6 to 40 carbon atoms, provided that the group R E It may contain an oxygen atom or a sulfur atom. (In the formula, R b1 , R b1’ , R b2 , R b2’ , n1 have the same meaning as above, R b7 represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, n4 represents an integer of 1 to 6, and * represents a bond.

4. The charge transporting composition according to claim 3, wherein the crosslinking agent is at least one selected from the group consisting of the following formulae (1) to (7):

5. The charge transporting composition according to claim 1, wherein the content of said crosslinking agent is 0.01 to 1.0 by mass ratio relative to the charge transporting substance.

6. The above R 1 2. The charge transporting composition according to claim 1, wherein is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a fluoroalkyl group having 1 to 5 carbon atoms, or a tert-butoxycarbonyl group.

7. The charge transporting composition according to any one of claims 1 to 6, which is used for a hole collecting layer of a perovskite photoelectric conversion element.

8. A charge transporting thin film obtained from the charge transporting composition according to any one of claims 1 to 6.

9. The charge transporting thin film according to claim 8, which is a hole collecting layer of a perovskite photoelectric conversion element.

10. A perovskite photoelectric conversion device comprising the charge transport thin film according to claim 9.

11. The perovskite photoelectric conversion element according to claim 10, which is of an inverted stacking type.

12. A solar cell comprising the perovskite photoelectric conversion element according to claim 10.

13. A method for producing a charge transporting thin film for an organic photoelectric conversion element, which comprises applying the charge transporting composition according to claim 1 onto an active layer or an anode and baking the applied composition.

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