Charge-transporting composition

Abstract

Provided is a charge-transporting composition suitable for forming a charge-transporting thin film of a photoelectric conversion element, and capable of significantly improving the photoelectric conversion efficiency and durability of the obtained element, in particular, when used as a hole collection layer of a perovskite-type solar cell. For example, provided is a charge-transporting composition for forming a charge-transporting thin film in an organic photoelectric conversion element, the charge-transporting composition comprising: a charge-transporting substance represented by formula H-1; an electron-accepting dopant substance; and an organic solvent.

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 using perovskite semiconductor compounds in the active layer (hereinafter referred to as "perovskite solar cells"), 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 device 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 an object of the present invention is to provide a charge transport composition that is suitable for forming a charge transport thin film of a photoelectric conversion element, and in particular, when used as a hole collection layer of a perovskite solar cell, can significantly improve the durability of the resulting element.

[0008] As a result of extensive research into achieving the above object, the present inventors have found that a charge transport composition containing a specific charge transport substance, an electron-accepting dopant substance, and an organic solvent is suitable for forming a charge transport thin film in an organic photoelectric conversion element, and in particular, when used as a hole collection layer in a perovskite solar cell, it can significantly improve the durability 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, the charge transport composition comprising a charge transport substance represented by the following formula (1), an electron-accepting dopant substance, and an organic solvent: [(wherein, R 1 each independently represents a hydrogen atom, an aromatic hydrocarbon group which may have a substituent, a tert-butoxycarbonyl group, or a silyl group substituted with an alkyl group or an aromatic hydrocarbon group; R 2 each independently represents any one of groups represented by the following formulas [B1] to [B11]. (In the formula, R 3 ~R 23 , R 26 ~R 47 and R 49 ~R 150 each independently represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, or a diphenylamino group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a heteroaryl group having 2 to 20 carbon atoms, each of which may be substituted with a halogen atom; R 24 and R 25 are, independently of each other, Z 1R represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, which may be substituted with 48 is a hydrogen atom, Z 4 an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an alkynyl group having 2 to 20 carbon atoms, which may be substituted with Z 1 Ar represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, which may be substituted with 1 each independently represents an aryl group having 6 to 20 carbon atoms which may be substituted with a di(aryl group having 6 to 20 carbon atoms)amino group; Z 1 is a halogen atom, a nitro group, a cyano group, or Z 2 represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms, each of which may be substituted with 2 is a halogen atom, a nitro group, a cyano group, or Z 3 Z represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, each of which may be substituted with 3 represents a halogen atom, a nitro group or a cyano group; Z 4 is a halogen atom, a nitro group, a cyano group, or Z 5 Z represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, each of which may be substituted with 5 is a halogen atom, a nitro group, a cyano group, or Z 3 represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an alkynyl group having 2 to 20 carbon atoms, each of which may be substituted with one of the following: 2. The charge transport composition of 1, wherein the electron-accepting dopant substance is a salt composed of an anion represented by the following formula (An1) and its counter cation, or a borane compound represented by the following formula (Bo1): (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, Ar b1 ~Arb3 each independently represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent. 3. The charge transport composition of 2, wherein the salt is an onium salt. 4. The charge transport composition of 2, wherein the anion represented by formula (An1) is represented by the following formula [an1]: 5. The charge transport composition according to any one of 1 to 4, wherein the content of the electron-accepting dopant substance is 0.001 to 50 parts by mass relative to 1 part by mass of the charge transport substance. 1 are each independently an aromatic hydrocarbon group which may have a substituent, a tert-butoxycarbonyl group, or a silyl group substituted with an alkyl group or an aromatic hydrocarbon group. 2 are each independently a group represented by formula [B1] or [B4]. 2 is a group represented by formula [B1]. 9. A charge transport composition according to any one of 1 to 8, which is for use in a hole collection layer of a perovskite photoelectric conversion element. 10. A charge transport thin film obtained from the charge transport composition according to any one of 1 to 8. 11. A charge transport thin film according to 10, wherein the charge transport thin film is a hole collection layer of a perovskite photoelectric conversion element. 12. A perovskite photoelectric conversion element comprising the charge transport thin film according to 11. 13. The perovskite photoelectric conversion element according to 12, which is of a normal stack type. 14. A solar cell comprising the perovskite photoelectric conversion element according to 12. 15. A method for producing a charge transport thin film for an organic photoelectric conversion element, which comprises applying the charge transport composition according to any one of 1 to 9 onto an active layer or an anode, followed by baking. 16. A compound represented by the following formula (X): (In the formula, R a are each independently a halogen atom or an alkoxy group having 1 to 6 carbon atoms; R b are each independently a hydrogen atom or a fluorine atom.) 17. A compound of 16 represented by the following formula (X-1) or (X-2):

[0010] The charge transport composition of the present invention is suitable for forming a charge transport thin film for a photoelectric conversion element. In particular, when the charge transport thin film is used as a hole collection layer of a perovskite photoelectric conversion element, a perovskite photoelectric conversion element having high durability can be obtained.

[0011] The present invention will be described in more detail below. The charge transport composition of the present invention is a charge transport composition for forming a charge transport thin film in an organic photoelectric conversion element, and is characterized by containing a charge transport substance represented by the following formula (1), an electron-accepting dopant substance, and an organic solvent.

[0012] [1] Charge transporting substance <Charge transporting substance represented by formula (1)>

[0013]

[0014] In formula (1), R 1 represent, independently of each other, a hydrogen atom, an aromatic hydrocarbon group which may have a substituent, a tert-butoxycarbonyl group, or a silyl group substituted with an alkyl group or an aromatic hydrocarbon group.

[0015] 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, with a phenyl group being preferred.

[0016] Examples of the substituent on the aromatic hydrocarbon group include a halogen atom, an alkyl group having 1 to 20 carbon atoms which may be substituted with a halogen atom, and an alkoxy group having 1 to 20 carbon atoms.

[0017] 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.

[0018] The alkyl group having 1 to 20 carbon atoms may be linear, branched, or cyclic, and examples thereof include linear or branched alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl groups; and cyclic alkyl groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, bicyclobutyl, bicyclopentyl, bicyclohexyl, bicycloheptyl, bicyclooctyl, bicyclononyl, and bicyclodecyl groups.

[0019] Examples of alkyl groups substituted with halogen atoms (halogenated alkyl groups) include the above alkyl groups in which at least one carbon atom is substituted with a halogen group. Specific examples of the halogenated alkyl group include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a bromodifluoromethyl group, a 2-chloroethyl group, a 2-bromoethyl group, a 1,1-difluoroethyl group, a 2,2,2-trifluoroethyl group, a 1,1,2,2-tetrafluoroethyl group, a 2-chloro-1,1,2-trifluoroethyl group, a pentafluoroethyl group, a 3-bromopropyl group, a 2,2,3,3-tetrafluoropropyl group, a 1,1,2,3,3,3-hexafluoropropyl group, a 1,1,1,3,3,3-hexafluoropropan-2-yl group, a 3-bromo-2-methylpropyl group, a 4-bromobutyl group, a perfluoropentyl group, and a 2-(perfluorohexyl)ethyl group.

[0020] Examples of the alkoxy group having 1 to 20 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-pentyloxy group, an i-pentyloxy group, a 2-methylbutoxy group, a 1,1-dimethylpropoxy group, a neopentyloxy group, a 3,3-dimethylbutoxy group, a 1-ethylpropoxy group, an n-hexyloxy group, a benzyloxy group, a naphthylmethyloxy group, a 1-phenylethyloxy group, a 2-phenylethyloxy group, a 2-naphthylethyloxy group, and a 3,3-diphenylpropoxy group. Examples of the silyl group substituted with an alkyl group include trialkylsilyl groups in which each alkyl group has 1 to 10 carbon atoms, such as a trimethylsilyl group, a triethylsilyl group, a tri-n-propylsilyl group, a triisopropylsilyl group, a tributylsilyl group, a tripentylsilyl group, a trihexylsilyl group, a tert-butyldimethylsilyl group, a propyldimethylsilyl group, a pentyldimethylsilyl group, a hexyldimethylsilyl group, an octyldimethylsilyl group, and a decyldimethylsilyl group.

[0021] Examples of the silyl group substituted with an aromatic hydrocarbon group include arylsilyl groups having an aryl group having 6 to 20 carbon atoms, such as a phenyldimethylsilyl group, a tert-butyldiphenylsilyl group, a triphenylsilyl group, and a trinaphthylsilyl group.

[0022] In the present invention, R 1 Specific examples of groups suitable as include, but are not limited to, the following groups:

[0023] (In the formula, Me represents a methyl group.)

[0024] In the above formula (1), R 2 are each independently any of the groups represented by the following formulae [B1] to [B11], and are particularly preferably any of the groups represented by the following formulae [B1′] to [B11′].

[0025]

[0026]

[0027] Here, R 3 ~R 23 , R 26 ~R 47 and R 49 ~R 150 R each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, or a diphenylamino group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a heteroaryl group having 2 to 20 carbon atoms, each of which may be substituted with a halogen atom. 24 and R 25 are, independently of each other, Z 1 R represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, which may be substituted with 48 is a hydrogen atom, Z 4 an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an alkynyl group having 2 to 20 carbon atoms, which may be substituted with Z 1 Z represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, which may be substituted with 1 is a halogen atom, a nitro group, a cyano group, or Z 2 Z represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms, which may be substituted with 2 is a halogen atom, a nitro group, a cyano group, or Z 3 Z represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, which may be substituted by 3 represents a halogen atom, a nitro group, or a cyano group. 4 is a halogen atom, a nitro group, a cyano group, or Z 5 Z represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, which may be substituted by 5 is a halogen atom, a nitro group, a cyano group, or Z 3 and represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an alkynyl group having 2 to 20 carbon atoms, which may be substituted with one of the following:

[0028] 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.

[0029] The alkyl group having 1 to 20 carbon atoms may be linear, branched, or cyclic, and examples thereof include linear or branched alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl groups; and cyclic alkyl groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, bicyclobutyl, bicyclopentyl, bicyclohexyl, bicycloheptyl, bicyclooctyl, bicyclononyl, and bicyclodecyl groups.

[0030] Examples of alkenyl groups having 2 to 20 carbon atoms include ethenyl, n-1-propenyl, n-2-propenyl, 1-methylethenyl, n-1-butenyl, n-2-butenyl, n-3-butenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, 1-ethylethenyl, 1-methyl-1-propenyl, 1-methyl-2-propenyl, n-1-pentenyl, n-1-decenyl, and n-1-eicosenyl groups.

[0031] Examples of the alkynyl group 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.

[0032] Examples of the alkoxy group having 1 to 20 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-pentyloxy group, an i-pentyloxy group, a 2-methylbutoxy group, a 1,1-dimethylpropoxy group, a neopentyloxy group, a 3,3-dimethylbutoxy group, a 1-ethylpropoxy group, an n-hexyloxy group, a benzyloxy group, a naphthylmethyloxy group, a 1-phenylethyloxy group, a 2-phenylethyloxy group, a 2-naphthylethyloxy group, and a 3,3-diphenylpropoxy group.

[0033] Examples of the aryl group having 6 to 20 carbon atoms include a phenyl 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.

[0034] Examples of heteroaryl groups having 2 to 20 carbon atoms include oxygen-containing heteroaryl groups such as 2-thienyl, 3-thienyl, 2-furanyl, 3-furanyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 3-isoxazolyl, 4-isoxazolyl, and 5-isoxazolyl groups, and sulfur-containing heteroaryl groups such as 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 3-isothiazolyl, 4-isothiazolyl, and 5-isothiazolyl groups. group, 2-imidazolyl group, 4-imidazolyl group, 2-pyridyl group, 3-pyridyl group, 4-pyridyl group, 2-pyrazyl group, 3-pyrazyl group, 5-pyrazyl group, 6-pyrazyl group, 2-pyrimidyl group, 4-pyrimidyl group, 5-pyrimidyl group, 6-pyrimidyl group, 3-pyridazyl group, 4-pyridazyl group, 5-pyridazyl group, 6-pyridazyl group, 1,2,3-triazin-4-yl group, 1,2,3-triazin-5-yl group, 1,2,4-triazin-3-yl group , 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 and nitrogen-containing heteroaryl groups such as 1-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.

[0035] In particular, R 3 ~R 23 , R 26 ~R 47 and R 49 ~R 150is preferably a hydrogen atom, a fluorine atom, a cyano group, a diphenylamino group which may be substituted with a halogen atom, an alkyl group having 1 to 20 carbon atoms which may be substituted with a halogen atom, an aryl group having 6 to 20 carbon atoms which may be substituted with a halogen atom, or a heteroaryl group having 2 to 20 carbon atoms which may be substituted with a halogen atom, more preferably a hydrogen atom, a fluorine atom, a cyano group, an alkyl group having 1 to 10 carbon atoms which may be substituted with a halogen atom, or a phenyl group which may be substituted with a halogen atom, still more preferably a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group, and most preferably a hydrogen atom. 24 and R 25 As for Z, 1 an aryl group having 6 to 14 carbon atoms which may be substituted with 1 A heteroaryl group having 2 to 14 carbon atoms which may be substituted by is preferred, and Z 1 An aryl group having 6 to 14 carbon atoms which may be substituted by is more preferred, and Z 1 a phenyl group optionally substituted with 1 a 1-naphthyl group optionally substituted by 1 Even more preferred is a 2-naphthyl group optionally substituted with R 48 Examples of the group include a hydrogen atom and Z 1 an aryl group having 6 to 20 carbon atoms which may be substituted with 1 a heteroaryl group having 2 to 20 carbon atoms which may be substituted by 4 A hydrogen atom, Z 1 an aryl group having 6 to 14 carbon atoms which may be substituted with 1 a heteroaryl group having 2 to 14 carbon atoms which may be substituted by 4 More preferred is an alkyl group having 1 to 10 carbon atoms which may be substituted with a hydrogen atom, Z 1 an aryl group having 6 to 14 carbon atoms which may be substituted with 1 a nitrogen-containing heteroaryl group having 2 to 14 carbon atoms which may be substituted with 4 More preferably, the alkyl group having 1 to 10 carbon atoms may be substituted with a hydrogen atom, Z 1a phenyl group optionally substituted with 1 a 1-naphthyl group optionally substituted by 1 a 2-naphthyl group optionally substituted by 1 a 2-pyridyl group optionally substituted by 1 a 3-pyridyl group optionally substituted by 1 a 4-pyridyl group optionally substituted by 4 A methyl group optionally substituted with is more preferred.

[0036] Also, Ar 1 are each independently an aryl group having 6 to 20 carbon atoms which may be substituted with a di(aryl group having 6 to 20 carbon atoms)amino group. Specific examples of the aryl group having 6 to 20 carbon atoms include those described above, and specific examples of the di(aryl group having 6 to 20 carbon atoms)amino group include a diphenylamino group, a 1-naphthylphenylamino group, a di(1-naphthyl)amino group, a 1-naphthyl-2-naphthylamino group, and a di(2-naphthyl)amino group. 1 As the alkyl group, a phenyl 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, a 9-phenanthryl group, a p-(diphenylamino)phenyl group, a p-(1-naphthylphenylamino)phenyl group, a p-(di(1-naphthyl)amino)phenyl group, a p-(1-naphthyl-2-naphthylamino)phenyl group, or a p-(di(2-naphthyl)amino)phenyl group is preferred, and a p-(diphenylamino)phenyl group is more preferred.

[0037] Below, R 2 Specific examples of groups suitable for the group are listed below, but the present invention is not limited to these.

[0038] (In the formula, DPA represents a diphenylamino group.)

[0039]

[0040]

[0041] (In the formula, R 48 has the same meaning as above.)

[0042]

[0043]

[0044]

[0045]

[0046] In the formula (1), in consideration of the ease of synthesis of the resulting aniline derivative, R 2 are all the same group, and R 1 are preferably all the same group.

[0047] In addition, R 24 , R 25 and R 48 In this case, Z 1 represents a halogen atom, a nitro group, a cyano group, Z 2 an alkyl group having 1 to 10 carbon atoms which may be substituted with 2 an alkenyl group having 2 to 10 carbon atoms which may be substituted by 2 an alkynyl group having 2 to 10 carbon atoms which may be substituted by 2 An alkoxy group having 1 to 10 carbon atoms which may be substituted with a halogen atom, a nitro group, a cyano group, Z 2 an alkyl group having 1 to 3 carbon atoms which may be substituted with 2 an alkenyl group having 2 to 3 carbon atoms which may be substituted by 2 an alkynyl group having 2 to 3 carbon atoms which may be substituted by 2 more preferably an alkoxy group having 1 to 3 carbon atoms which may be substituted by a fluorine atom, Z 2 an alkyl group having 1 to 3 carbon atoms which may be substituted with 2 an alkenyl group having 2 to 3 carbon atoms which may be substituted by 2 an alkynyl group having 2 to 3 carbon atoms which may be substituted by 2 An alkoxy group having 1 to 3 carbon atoms which may be substituted with is even more preferred.

[0048] R 24 , R 25and R 48 In this case, Z 4 represents a halogen atom, a nitro group, a cyano group, Z 5 An aryl group having 6 to 14 carbon atoms which may be substituted by a halogen atom, a nitro group, a cyano group, Z 5 An aryl group having 6 to 10 carbon atoms which may be substituted with a fluorine atom, Z 5 An aryl group having 6 to 10 carbon atoms which may be substituted with a fluorine atom, Z 5 A phenyl group optionally substituted with is more preferred.

[0049] R 24 , R 25 and R 48 In this case, Z 2 represents a halogen atom, a nitro group, a cyano group, Z 3 An optionally substituted aryl group having 6 to 14 carbon atoms is preferred, and a halogen atom, a nitro group, a cyano group, Z 3 An aryl group having 6 to 10 carbon atoms which may be substituted with a fluorine atom, Z 3 An aryl group having 6 to 10 carbon atoms which may be substituted with a fluorine atom, Z 3 A phenyl group optionally substituted with is more preferred.

[0050] R 24 , R 25 and R 48 In this case, Z 5 represents a halogen atom, a nitro group, a cyano group, Z 3 an alkyl group having 1 to 10 carbon atoms which may be substituted with 3 an alkenyl group having 2 to 10 carbon atoms which may be substituted by 3 and a halogen atom, a nitro group, a cyano group, a Z 3 an alkyl group having 1 to 3 carbon atoms which may be substituted with 3 an alkenyl group having 2 to 3 carbon atoms which may be substituted by 3 More preferred is an alkynyl group having 2 to 3 carbon atoms which may be substituted by a fluorine atom, Z 3 an alkyl group having 1 to 3 carbon atoms which may be substituted with3 an alkenyl group having 2 to 3 carbon atoms which may be substituted by 3 An alkynyl group having 2 to 3 carbon atoms which may be substituted with is even more preferred.

[0051] R 24 , R 25 and R 48 In this case, Z 3 is preferably a halogen atom, more preferably a fluorine atom.

[0052] On the other hand, R 3 ~R 23 , R 26 ~R 47 and R 49 ~R 150 In this case, Z 1 represents a halogen atom, a nitro group, a cyano group, Z 2 an alkyl group having 1 to 3 carbon atoms which may be substituted with 2 an alkenyl group having 2 to 3 carbon atoms which may be substituted by 2 an alkynyl group having 2 to 3 carbon atoms which may be substituted by 2 An alkoxy group having 1 to 3 carbon atoms which may be substituted with a halogen atom, Z 2 an alkyl group having 1 to 3 carbon atoms which may be substituted with 2 more preferably an alkoxy group having 1 to 3 carbon atoms which may be substituted by a fluorine atom, Z 2 a methyl group optionally substituted with 2 Even more preferred is a methoxy group optionally substituted with

[0053] R 3 ~R 23 , R 26 ~R 47 and R 49 ~R 150 In this case, Z 4 represents a halogen atom, a nitro group, a cyano group, Z 5 An aryl group having 6 to 10 carbon atoms which may be substituted with a halogen atom, Z 5 An aryl group having 6 to 10 carbon atoms which may be substituted with a fluorine atom, Z 5 A phenyl group optionally substituted with is even more preferred.

[0054] R 3 ~R 23 , R 26 ~R 47 and R 49 ~R 150 In this case, Z 2 represents a halogen atom, a nitro group, a cyano group, Z 3 An aryl group having 6 to 10 carbon atoms which may be substituted with a halogen atom, Z 3 An aryl group having 6 to 10 carbon atoms which may be substituted with a fluorine atom, Z 3 A phenyl group optionally substituted with is even more preferred.

[0055] R 3 ~R 23 , R 26 ~R 47 and R 49 ~R 150 In this case, Z 5 represents a halogen atom, a nitro group, a cyano group, Z 3 an alkyl group having 1 to 3 carbon atoms which may be substituted with 3 an alkenyl group having 2 to 3 carbon atoms which may be substituted by 3 and a halogen atom, Z 3 More preferred is an alkyl group having 1 to 3 carbon atoms which may be substituted with a fluorine atom, Z 3 A methyl group optionally substituted with is even more preferred.

[0056] R 3 ~R 23 , R 26 ~R 47 and R 49 ~R 150 In this case, Z 3 is preferably a halogen atom, more preferably a fluorine atom.

[0057] In the present invention, R 48 Specific examples of groups suitable as include, but are not limited to, the following groups:

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065] In the present invention, the number of carbon atoms in the alkyl group, alkenyl group, alkynyl group, and alkoxy group is preferably 10 or less, more preferably 6 or less, and even more preferably 4 or less. The number of carbon atoms in the aryl group and heteroaryl group is preferably 14 or less, more preferably 10 or less, and even more preferably 6 or less.

[0066] Specific examples of the charge transporting substance represented by the formula (1) include, but are not limited to, the following.

[0067] (In the formula, Me has the same meaning as above.)

[0068] The aniline derivative represented by formula (1) of the present invention can be synthesized according to the methods described in WO 2015 / 050253, WO 2019 / 177049, etc.

[0069] <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.

[0070] [2] Electron-Accepting Dopant Substance The charge-transporting composition of the present invention contains an electron-accepting dopant substance (hereinafter, sometimes simply referred to as a "dopant substance"). A suitable dopant substance can be selected and used depending on the application of the resulting thin film, for example, to adjust the ionization potential or improve the charge transport ability. The dopant substance is not particularly limited as long as it dissolves in at least one solvent used in the charge-transporting composition, and both organic and inorganic dopant substances can be used.

[0071] Examples of organic dopant substances include salts (ionic compounds) composed of anions represented by the following formula (An1) and their counter cations, borane compounds represented by the formula (Bo1) described below, arylsulfonic acids, arylsulfonic acid esters, tetracyanoquinodimethane derivatives, benzoquinone derivatives, etc. In the present invention, ionic compounds and borane compounds can be preferably used from the viewpoint of further improving the durability of the resulting element.

[0072] <Salt (ionic compound) composed of an anion represented by formula (An1) and its counter cation> (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.

[0073] 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.

[0074] 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 a4It 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.

[0075] Examples of the anion of the above formula (An1) that can be suitably used in the present invention include, but are not limited to, those represented by the formula [an1].

[0076]

[0077] 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):

[0078]

[0079] In formula (Ct1), R t1 and R t2 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.

[0080] As the counter cation, an ion represented by the following formula (Ct2) can also be used.

[0081]

[0082] In formula (Ct2), A 1 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. Among these, elements in the fifth period or earlier (third to fifth periods) of the periodic table are preferred in the present invention from the viewpoint of electron-accepting properties and availability. That is, A 1 is preferably any one of a sulfur atom, a selenium atom and a tellurium atom, and more preferably a sulfur atom.

[0083] R t3 Is A 1 represents an organic group bonded to R via a carbon atom; t4 and R t5 R are each independently an optional substituent. t3 ~R t5 Two or more adjacent groups may be bonded to each other to form a ring.

[0084] R t3 Is A 1 The type of organic group is not particularly limited as long as it has a carbon atom at the bonding site with R. t3 The molecular weight of each of R is usually 1,000 or less, preferably 500 or less, including the value of the substituent. t3 Preferred 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.

[0085] 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, with a phenyl group and a tolyl group being preferred.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] R t4 and R t5 is not particularly limited as long as it does not contradict the spirit of the present invention. t4 and R t5 The molecular weight of each of R is usually 1,000 or less, preferably 500 or less, including the value of the substituent. t4 and R t5 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. t3 As with A, A has a large electron-accepting property. 1 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.

[0091] The alkyl group, alkenyl group, alkynyl group, aromatic hydrocarbon group, and aromatic heterocyclic group include R t3 The same as those explained above can be mentioned.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] Specific examples of the alkylsulfonyl group and the arylsulfonyl group include a mesyl group and a tosyl group.

[0104] Specific examples of the sulfonyloxy group include a mesyloxy group and a tosyloxy group.

[0105] Specific examples of the silyl group include a trimethylsilyl group and a triphenylsilyl group.

[0106] Above, R t3 , R t4 and R t5The 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, t3 , R t4 and R t5 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 arylthio group, an aromatic hydrocarbon group, or an aromatic heterocyclic group is preferred.

[0107] Specific examples of the cations represented by the above formulas (Ct1) and (Ct2) include, but are not limited to, cations represented by the following formulas (Ct1-1) and (Ct2-1) to (Ct2-5).

[0108]

[0109]

[0110] Furthermore, in addition to the cations represented by the above formulae (Ct1) and (Ct2), the following cations can also be mentioned as suitable.

[0111] Among the above, ionic compounds which are combinations of anions and cations represented by the following formulas (AC1) to (AC8), particularly the following formulas (AC1) to (AC7), can be suitably used (see, for example, Japanese Patent No. 5381931):

[0112]

[0113]

[0114]

[0115] Furthermore, onium borate salts (which are electrically neutral salts) consisting of a monovalent or divalent anion represented by formula (An2) and a counter cation represented by any of the above formulae (Ct2-5), (Ct3) to (Ct6) can also be suitably used.

[0116]

[0117] 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 -.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] Examples of the substituent on the heteroaryl group include the same substituents as those exemplified for the aryl group.

[0127] L is an alkylene group, —NH—, an oxygen atom, a sulfur atom, or —CN + - represents -CN+ - is preferred.

[0128] 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.

[0129] Anions of the above formula (An2) that can be suitably used in the present invention include, but are not limited to, those represented by formula (An2-1).

[0130]

[0131] 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.

[0132] 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.

[0133] Furthermore, when the charge-transporting composition of the present invention contains an ionic compound, the content thereof is preferably about 0.001 to 50, more preferably about 0.005 to 10, and even more preferably about 0.01 to 5, by mass ratio relative to 1 of the charge-transporting substance.

[0134] <Borane Compound Represented by Formula (Bo1)> (In the formula, Ar b1 ~Ar b3 each independently represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent.

[0135] In formula (Bo1), examples of the aromatic hydrocarbon group and aromatic heterocyclic group include the same as those exemplified in formula (An1). b1 ~Ar b3 It is more preferable that at least one of the groups has one or more fluorine atoms or chlorine atoms as a substituent. b1 ~Ar b3 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.

[0136] Specific examples of the borane compound represented by the above formula (Bo1) include, but are not limited to, those shown below.

[0137]

[0138] The borane compound 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 borane compound.

[0139] Furthermore, when the charge-transporting composition of the present invention contains a borane compound, the content thereof is preferably about 0.001 to 50 parts by mass, more preferably about 0.005 to 10 parts by mass, and even more preferably about 0.01 to 5 parts by mass, relative to 1 part of the charge-transporting substance.

[0140] <Arylsulfonic Acid> As the arylsulfonic acid, a compound represented by the following formula (As1) can be suitably used.

[0141] (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.)

[0142] In the present invention, examples of arylsulfonic acids that can be suitably used include compounds represented by the following formula (As1-1).

[0143]

[0144] The arylsulfonic acid represented by formula (As1) can be synthesized by a known method, for example, by the method described in WO 2006 / 025342.

[0145] 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 0.005 to 10 parts by mass, and even more preferably about 0.01 to 5 parts by mass, per 1 part of the charge-transporting substance.

[0146] <Tetracyanoquinodimethane Derivatives> Specific examples of tetracyanoquinodimethane derivatives 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 benzoquinone derivatives 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.

[0147] Furthermore, examples of the halotetracyanoquinodimethane compound include compounds represented by formula (Tq1).

[0148]

[0149] 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.

[0150] 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.

[0151] 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 0.005 to 10, and even more preferably about 0.01 to 5, by mass ratio relative to 1 of the charge-transporting substance.

[0152] <Heteropolyacid> As the inorganic dopant substance, heteropolyacid is preferable, and specific examples thereof include phosphomolybdic acid, silicomolybdic acid, phosphotungstic acid, phosphotungstomolybdic acid, and silicotungstic acid.

[0153] 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 by formula (Ht1) or a Dawson type chemical structure shown by formula (Ht2), and are formed by condensing 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).

[0154]

[0155] 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.

[0156] 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.

[0157] 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.

[0158] When the charge transport composition of the present invention contains a heteropolyacid, the content thereof is preferably about 0.001 to 50 parts by mass, more preferably about 0.005 to 10 parts by mass, and even more preferably about 0.01 to 5 parts by mass, per 1 part of the charge transport substance.

[0159] [3] Organic Solvent The charge transport composition is generally in the form of a coating liquid in order to form a uniform thin film. The charge transport composition of the present invention can also use an organic solvent that can dissolve the charge transport material and the electron-accepting dopant material well. Furthermore, damage to the underlying perovskite layer can adversely affect the power generation performance and durability of the device. Therefore, it is desirable to select an organic solvent that does not damage the perovskite layer as the organic solvent used in the charge transport composition.

[0160] Specific examples of the organic solvent include toluene, o-xylene, m-xylene, p-xylene, acetonitrile, ethanol, isopropyl alcohol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, propylene glycol monomethyl ether acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, n-butyl acetate, ethyl acetate, cyclohexanone, and cyclopentanone.

[0161] In addition to the above-mentioned solvents, the organic solvent contained in the charge-transporting composition of the present invention may also be a suitable solvent for the purposes of complementing the solubility of the solute, adjusting the drying rate, and further improving 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.

[0162] For example, 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-propanediol, 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, 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, 2-(2-ethoxyethoxy)ethyl acetate ester, diethylene glycol acetate, triethylene glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methyl lactate, ethyl lactate, methyl acetate, ethyl 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-methoxypropionate acid, propyl 3-methoxypropionate, butyl 3-methoxypropionate, methyl lactic acid ester, ethyl lactic acid ester, n-propyl lactic acid ester, n-butyl lactic acid ester, isoamyl lactic acid ester, 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,Examples of suitable amines include 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.

[0163] In the present invention, the organic solvent preferably used is toluene, o-xylene, acetonitrile, isopropyl alcohol, 1-butanol, 1-pentanol, propylene glycol monomethyl ether acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, n-butyl acetate, ethyl acetate, cyclohexanone, or cyclopentanone.

[0164] 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.

[0165] [4] 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.

[0166] 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.

[0167] 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.

[0168] [5] Other Additives 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.

[0169] [6] Charge-Transporting Composition 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 15.0 mass %, and even more preferably 1.0 to 10.0 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.

[0170] 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 formed and the solid content concentration, but is usually about 0.1 to 50 mPa·s at 25°C.

[0171] The charge transport composition of the present invention can be prepared by mixing a charge transport material, an electron-accepting dopant material, 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, any of the following methods can be employed, as long as the solid content is uniformly dissolved or dispersed in the solvent: a method of dissolving a specific polymer as a charge transport material in an organic solvent and then dissolving an electron-accepting dopant material in the solution; a method of dissolving an electron-accepting dopant material 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 material and then introducing the mixture into a solvent and dissolving the mixture.

[0172] 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.

[0173] [7] Charge-Transporting Thin Film The hole-collecting layer of the present invention can be formed by applying the charge-transporting composition described above to the active layer in a normal-layer stacking perovskite solar cell or to the anode in an inverted-layer stacking perovskite solar cell and then baking the composition. The normal-layer stacking type is a preferred embodiment of the present invention. For application, the viscosity and surface tension of the composition, the desired thin film thickness, and other factors can be taken into consideration, and an optimal method can be selected from various wet processes such as drop casting, spin coating, blade coating, dip coating, roll coating, bar coating, die coating, inkjet printing, and printing (relief printing, intaglio printing, lithography, screen printing, etc.). Typically, application is performed in an inert gas atmosphere at room temperature and normal pressure. However, application may also be performed in the air (in the presence of oxygen) or while heating, as long as the compounds in the composition do not decompose or the composition does not change significantly.

[0174] 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 200 nm. Methods for changing the film thickness include changing the solid concentration in the composition, changing the amount of solution at the time of application, and the like.

[0175] [8] Perovskite Solar Cells 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.

[0176] 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.

[0177] [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.

[0178] [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.

[0179] 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.

[0180] 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.

[0181] 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.

[0182] 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.

[0183] 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.

[0184] 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.

[0185] 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.

[0186] 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.

[0187] 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.

[0188] 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.

[0189] 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.

[0190] [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).

[0191] 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.

[0192] 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.

[0193] 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.

[0194] [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.

[0195] [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).

[0196] 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.

[0197] (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.

[0198] [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.

[0199] [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.

[0200] [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.

[0201] [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.

[0202] [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.

[0203] 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.

[0204] The present invention also provides a compound represented by the following formula (X) as a novel compound suitable for a charge transport composition for forming a charge transport thin film in an organic photoelectric conversion element.

[0205] (In the formula, R aare each independently a halogen atom or an alkoxy group having 1 to 6 carbon atoms; R b are each independently a hydrogen atom or a fluorine atom.

[0206] R a Examples of the halogen atom represented by the formula (1) include those exemplified in the explanation of the formula (1), but an iodine atom is preferred.

[0207] R a Examples of the alkoxy group having 1 to 6 carbon atoms represented by the formula (1) include those exemplified in the explanation of the formula (1) above, but a methoxy group and an ethoxy group are preferred, and a methoxy group is more preferred.

[0208] Specific preferred examples of the compound represented by formula (X) include compounds represented by the following formulas (X-1) to (X-2), but are not limited thereto.

[0209]

[0210] 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.

[0211] <Apparatus> The apparatuses used in the examples are as follows: (1) Ionization potential measurement apparatus: AC-3 manufactured by Riken Keiki Co., Ltd. (2) Preparation of photoelectric conversion element Glove box: VAC glove box system manufactured by Yamahachi Bussan Co., Ltd. Vapor deposition apparatus: Vacuum deposition apparatus manufactured by Aoyama Engineering Co., Ltd. (3) Evaluation of element characteristics Solar simulator: OTENTOSUN-III manufactured by Bunko Keiki Co., Ltd., AM1.5G filter, radiant intensity: 100 mW / cm 2 Source measure unit: Keithley Instruments, Inc., 2612A

[0212] The abbreviations used in the preparation of the charge transporting compositions are as follows: <Charge transporting substances> Charge transporting substances represented by the following formulae H-1 to H-5 and Spiro-OMeTAD. <Electron-accepting dopant substances> Electron-accepting dopant substances represented by the following formulas D-1 to D-8 and LiTFSI+FK209 <Solvent> ACN: Acetonitrile PGMEA: Propylene glycol monomethyl ether acetate CB: Chlorobenzene

[0213] 1 H-NMR spectra were measured using a nuclear magnetic resonance spectrometer AVANCE III HD (Bruker). Chemical shift values ​​are expressed in ppm, and deuterated tetrahydrofuran was used as the solvent. 1 In the H-NMR spectrum, signals derived from residual protons of the solvent were used, and tetrahydrofuran was used as an internal standard, with δ 1.73 ppm and 3.58 ppm.

[0214] [1] Synthesis of Charge-Transporting Materials [Synthesis of H-1, H-4, and H-5] H-1 was synthesized according to Production Example 24 of WO 2015 / 050253, H-4 was synthesized according to Example 2 of WO 2019 / 177049, and H-5 was synthesized according to Production Example 18 of WO 2015 / 050253.

[0215] [Example 1] [Synthesis of H-2]

[0216] AN-1 (827 mg, 0.70 mmol) synthesized according to the method described in Preparation Example 9 of WO 2015 / 050253 was placed in a recovery flask, and the atmosphere inside the recovery flask was replaced with nitrogen. Subsequently, tetrahydrofuran (3.5 mL) was added to the recovery flask and stirred until homogenous. While cooling the recovery flask in an ice bath, n-butyllithium (1.6 M hexane solution, 1.33 mL, 2.1 mmol) was added dropwise to the reaction solution. The temperature of the reaction solution was returned to room temperature, and after stirring for 30 minutes, pentafluoroiodobenzene (2.49 g, 8.4 mmol) was added to the reaction solution, which was then stirred for 20 hours in a 35°C oil bath. The reaction solution was added to a 4:1 methanol:water solution, and the resulting solid was filtered off using a membrane filter. The resulting solid was dried under vacuum at 60°C for 6 hours to obtain the target product, H-2 (yield: 1.35 g, 68%). 1 ​H-NMR (500MHz, THF-d8): δ 7.96 (brt, 3H), 7.90 (brd, 3H), 7.28 (brt, 3H), 7.19 (brdt, 3H). 7.16-7.02 (m, 17H), 6.95-6.87 (m, 20H), 6.83 (brd, 4H), 6.80 (brt, 4H) MALDI-TOF-MS m / z found: 2003.19 ([M + calcd:2003.17)

[0217] Example 2 Synthesis of H-3

[0218] AN-2 (1.00 g, 1.46 mmol) synthesized according to the method described in Synthesis Example 1 of WO 2014 / 115865, CZ-1 (1.76 g, 5.00 mmol) synthesized according to the method described in Preparation Example 1-3 of WO 2020 / 241730, Pd(dba)2 (52.1 mg, 0.0906 mmol) and t-butoxy sodium (0.61 g, 6.35 mmol) were placed in a recovery flask, and the recovery flask was then purged with nitrogen. Xylene (20 mL) and di-t-butylphosphine (0.32 g, 2.19 mmol) were placed in the recovery flask and stirred at 100 ° C. for 3 hours. After stirring was completed, the reaction solution was cooled to room temperature, and toluene and saturated saline were added to the reaction solution and the mixture was separated. Activated carbon (0.5 g) was added to the resulting organic layer and stirred at room temperature for 30 minutes. The activated carbon was removed by filtration, and the filtrate was concentrated. Ethyl acetate (50 mL) was added to the concentrate and redissolved. This solution was added dropwise to methanol (500 mL), and the resulting suspension was stirred at room temperature for 60 minutes. The suspension was then filtered, and the resulting residue was dried to obtain the desired charge-transporting material H-3 (yield: 1.53 g, 70%). 1 H-NMR (500MHz, THF-d8): δ 7.89-7.93 (m, 6H), 7.34-7.36 (m, 6H), 7.03-7.20 (m, 29H), 6.77-6.92 (m, 28H), 3.77 (s, 9H). MALDI-TOF-MS m / z found: 1499.63 ([M] + calcd:1500.63)

[0219] [2] Preparation of Charge Transport Composition [Example 3-1] 1 g of charge transport material H-1 was dissolved in 9 g of PGMEA to obtain a charge transport material solution. Separately, 0.5 g of electron-accepting dopant material D-1 was dissolved in 9.5 g of PGMEA to obtain an electron-accepting dopant material solution. PGMEA was added to the charge transport material solution to dilute the charge transport material to a predetermined concentration. The electron-accepting dopant material solution was added to the diluted solution so that the mass ratio of DP-1 to charge transport material H-1 was 0.1. The resulting mixture was filtered through a syringe filter with a pore size of 0.45 μm to prepare charge transport composition A1-1. The concentration of the charge transport material in the charge transport composition was 2.0 mass%. Hereinafter, the electron-accepting dopant material concentration relative to the charge transport material concentration 1 is referred to as D / H.

[0220] Examples 3-2 to 3-3 Charge transport compositions A1-2 and A1-3 were obtained in the same manner as in Example 3-1, except that the solutions were mixed so that the mass ratio of DP-1 to charge transport material H-1 was 0.2 and 0.5, respectively.

[0221] [Examples 3-4 to 3-31] Charge transport compositions A2-1 to A11-1 were prepared in the same manner as in Example 3-1, except that the charge transport material, electron-accepting dopant material, and D / H were changed based on the composition shown in Table 1. The concentration of the charge transport material in each charge transport composition was adjusted to 2.0% by mass.

[0222] Example 3-32: 1 g of charge transport material H-1 was dissolved in 9 g of toluene to obtain a charge transport material solution. Separately, 0.5 g of electron-accepting dopant material DP-1 was dissolved in 9.5 g of ACN to obtain an electron-accepting dopant material solution. Toluene was added to the charge transport material solution to dilute the charge transport material to a predetermined concentration. The electron-accepting dopant material solution was added to the diluted solution so that the mass ratio of DP-1 to charge transport material H-1 was 0.2. The resulting mixture was filtered through a syringe filter with a pore size of 0.45 μm to prepare charge transport composition A12-1. The concentration of the charge transport material in the charge transport composition was 2.0 mass%.

[0223] [Examples 3-33 to 3-35] Charge transport compositions A13-1 to A15-1 were prepared in the same manner as in Example 3-32, except that the charge transport material, electron-accepting dopant material, and D / H were changed based on the composition shown in Table 1. The concentration of the charge transport material in each charge transport composition was adjusted to 2.0% by mass.

[0224] Example 3-36: 1 g of charge transport material H-5 was dissolved in 9 g of toluene to obtain a charge transport material solution. Separately, 0.5 g of electron-accepting dopant material DP-2 was dissolved in 9.5 g of PGMEA to obtain an electron-accepting dopant material solution. Toluene was added to the charge transport material solution to dilute the charge transport material to a predetermined concentration. The electron-accepting dopant material solution was added to the diluted solution so that the mass ratio of DP-2 to charge transport material H-5 was 0.05. The resulting mixture was filtered through a syringe filter with a pore size of 0.45 μm to prepare charge transport composition A16-1. The concentration of the charge transport material in the charge transport composition was 2.0 mass%.

[0225] [Examples 3-37 to 3-41] Charge transport compositions A16-2 to A19-1 were prepared in the same manner as in Example 3-36, except that the charge transport material, electron-accepting dopant material, and D / H were changed based on the composition shown in Table 1. The concentration of the charge transport material in each charge transport composition was adjusted to 2.0% by mass.

[0226] [Example 3-42] 69 mg of charge transport material H-1 was dissolved in 800 μL of CB to obtain a charge transport material solution. Separately, as an electron-accepting dopant material, 287 mg of LiTFSI was dissolved in 500 μL of ACN, and 150 mg of FK209 was dissolved in 500 μL of ACN to obtain electron-accepting dopant material solution 1 and electron-accepting dopant material solution 2. 14 μL of electron-accepting dopant material solution 1, 17 μL of electron-accepting dopant material solution 2, and 27 μL of 4-tert-butylpyridine (tBP) were added to the charge transport material solution, and the mixture was filtered through a syringe filter with a pore size of 0.45 μm to obtain charge transport composition A20-1.

[0227] [Comparative Example 1-1] 1 g of charge transport material H-1 was dissolved in 9 g of PGMEA to obtain a charge transport material solution. PGMEA was added to the charge transport material solution to dilute it so that the concentration of the charge transport material in the solution became 2.0 mass %. The obtained diluted solution was filtered through a syringe filter with a pore size of 0.45 μm to prepare charge transport composition B1.

[0228] Comparative Examples 1-2 to 1-4 Charge transport compositions B2 to B4 were obtained in the same manner as in Comparative Example 1-1, based on the formulations shown in Table 2 below, except that the charge transport material was changed.

[0229] [Comparative Example 1-5] 1 g of charge transport material H-5 was dissolved in 9 g of toluene to obtain a charge transport material solution. Toluene was added to the charge transport material solution to dilute it so that the concentration of the charge transport material in the solution became 2.0 mass %. The obtained diluted solution was filtered through a syringe filter with a pore size of 0.45 μm to prepare charge transport composition B5.

[0230] Comparative Example 1-6 Charge transporting composition B6 was obtained in the same manner as in Example 3-5, except that Spiro-OMeTAD was used instead of charge transporting substance H-1.

[0231] Comparative Example 1-7 Charge transporting composition B7 was obtained in the same manner as in Example 3-42, except that Spiro-OMeTAD was used instead of charge transporting substance H-1.

[0232] Table 1 below summarizes the compositions of charge transporting compositions A1-1 to A20-1.

[0233]

[0234] Table 2 below summarizes the compositions of charge transporting compositions B1 to B7.

[0235]

[0236] [3] Preparation of a charge-transport composition film-formed substrate for ionization potential measurement [Example 4-1] A 20 mm x 20 mm glass substrate with an ITO transparent conductive layer was subjected to UV / ozone treatment for 15 minutes. The charge-transport composition A1-1 prepared in Example 1-1 was applied to this substrate by spin coating, and then annealed by heating at 100°C for 10 minutes to prepare a charge-transport composition film-formed substrate C1. The film thickness of the charge-transport composition was approximately 50 nm.

[0237] [Examples 4-2 to 4-36] Charge-transport composition film-formed substrates C2 to C36 were prepared in the same manner as in Example 4-1, except that the charge-transport composition was changed based on the formulation shown in Table 3. The film thickness of the charge-transport composition was approximately 50 nm.

[0238] Comparative Examples 2-1 to 2-4 Substrates D1 to D4 having a charge-transport composition film formed thereon were prepared in the same manner as in Example 4-1, except that the charge-transport composition was changed based on the formulation shown in Table 3. The film thickness of the charge-transport composition was approximately 50 nm.

[0239] [4] Measurement of Ionization Potential The ionization potential (Ip) of the charge-transport composition-coated substrates prepared in Examples 4-1 to 4-36 and Comparative Examples 2-1 to 2-4 was measured using an ionization potential measurement device. The set light intensity was 20.0 nW, and measurements were made in 0.1 eV increments over the range of 4.00 to 7.00 eV, and Ip was calculated from the threshold energy of photoelectron emission. The results are shown in Table 3.

[0240]

[0241] For all charge transport materials, the addition of an electron-accepting dopant resulted in the same or deeper Ip. The greater the amount of electron-accepting dopant added, the deeper the Ip. The Ip of the charge transport composition was affected by the terminal structure of the charge transport material. In the case of terminal structures with electron-withdrawing properties, such as H-1 and H-2, the Ip was deep, while in the case of terminal structures with electron-donating properties, such as H-3, the Ip was shallow. Generally, in photoelectric conversion elements, the closer the work function of the active layer and the Ip of the charge transport layer are to each other, the smaller the energy barrier and the higher the power generation performance. For photoelectric conversion elements having a perovskite compound in the active layer, the work function changes depending on the composition of the perovskite compound, so it is preferable to also adjust the Ip of the charge transport layer. The charge transport composition of the present invention can be easily adjusted in Ip by the terminal structure or the addition of an electron-accepting dopant, making it a charge transport composition suitable for photoelectric conversion elements.

[0242] [5] Fabrication of Photoelectric Conversion Element <Preparation of Active Layer Precursor Liquid> [Preparation Example 1] In a glove box, 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. 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 mixture. Furthermore, 134 μL of a cesium iodide solution dissolved in DMSO to a concentration of 1.5 mol / L was added to prepare an active layer precursor liquid.

[0243] <Preparation of Coating Liquid for Electron Transport Layer> [Preparation Example 2] 73 μL of titanium diisopropoxide bis(acetylacetonate) (75% by mass, 2-propanol solution) was added to a vial. 927 μL of 2-propanol was further added. After stirring for 10 minutes, the mixture was filtered through a syringe filter with a pore size of 0.2 μm to prepare Coating Liquid 1 for Electron Transport Layer.

[0244] Preparation Example 3 1 g of titanium oxide paste (PST-18NR, manufactured by JGC Catalysts and Chemicals Co., Ltd.) was added to a vial. 7 g of ethanol was further added. After stirring for 10 minutes, ultrasonic treatment was performed for 1 hour to prepare Coating Solution 2 for an electron transport layer.

[0245] <Fabrication of Photoelectric Conversion Element> [Example 5-1] A 25 mm x 25 mm glass substrate on which an ITO transparent conductive layer serving as a cathode was patterned into 10 mm x 25 mm stripes was subjected to UV / ozone treatment for 15 minutes. The electron transport layer coating solution 1 obtained in Preparation Example 2 was applied to this substrate by spin coating (SC) and heated on a hot plate at 120°C for 10 minutes. Furthermore, the electron transport layer coating solution 2 obtained in Preparation Example 3 was applied to this substrate by SC and heated on a hot plate at 200°C for 10 minutes. The substrate was then baked in a muffle furnace at 500°C for 30 minutes to form an electron collection layer. The obtained substrate was introduced into a glove box, and the active layer precursor solution obtained in Preparation Example 1 was dripped onto the formed electron transport layer and coated by SC. Chlorobenzene was dripped onto the substrate in SC. The obtained 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 about 400 nm. The charge transport composition A1-1 prepared in Example 3-1 was dropped onto the formed active layer and applied by SC. The layer was heated on a hot plate at 100°C for 10 minutes to form a hole transport layer. The thickness of the hole transport layer was about 50 nm. Finally, the substrate on which the above layers were laminated was placed in a vacuum deposition apparatus, and the degree of vacuum in the apparatus was 1 x 10 -3 The chamber was evacuated to a pressure of 100 Pa or less, and a gold layer serving as the anode was evaporated to a thickness of 70 nm using a resistance heating method, thereby producing a photoelectric conversion element E1 having an area of ​​8 mm x 3 mm where the striped ITO layer and gold layer intersect.

[0246] [Examples 5-2 to 5-18] Photoelectric conversion elements E2 to E18 were fabricated in the same manner as in Example 5-1, except that the charge-transporting composition was changed. The film thickness of the charge-transporting composition in Example 5-18 was approximately 200 nm, and the film thickness in the other examples was approximately 50 nm.

[0247] Comparative Examples 3-1 to 3-2 Photoelectric conversion elements F1 and F2 were fabricated in the same manner as in Example 5-1, except that the charge transporting composition was changed. The film thickness of the charge transporting composition was about 200 nm.

[0248] <Evaluation of Device Characteristics> The short-circuit current density (Jsc [mA / cm2 The open circuit voltage (Voc [V]), fill factor (FF), and conversion efficiency (PCE [%]) of each photoelectric conversion element were measured. The PCE [%] results for each photoelectric conversion element are shown in Table 4. The PCE [%] was calculated using the following formula: PCE [%] = Jsc [mA / cm 2 ] × Voc [V] × FF ÷ Incident light intensity (100 [mW / cm 2 ) × 100

[0249]

[0250] By using the charge transport composition of the present invention in the hole transport layer of a photoelectric conversion element, power generation characteristics were obtained. It is believed that the interaction between the tertiary amine of the charge transport material and the electron-accepting dopant material increases the carrier density in the charge transport material, thereby realizing efficient hole transport.

[0251] <Heat Resistance Test> The photoelectric conversion elements E2, E5, E6, E18, F1, and F2 were placed on a hot plate set at 85° C. in a glove box, and the short-circuit current density (Jsc [mA / cm 2 The heat resistance of the photoelectric conversion element was evaluated by measuring the open circuit voltage (Voc [V]), fill factor (FF), and conversion efficiency (PCE [%]). Table 5 shows the initial PCE, PCE after 100 hours, and PCE retention of each photoelectric conversion element.

[0252]

[0253] Photoelectric conversion elements using the charge transport composition of the present invention in the hole transport layer exhibited high heat resistance, with no decrease in PCE during heat resistance testing. On the other hand, when the commonly used Spiro-OMeTAD was used in the hole collection layer, the PCE decreased. Comparing the heat resistance of Example 5-2 with Comparative Example 3-1 and Example 5-18 with Comparative Example 3-2, the charge transport composition of the present invention exhibited higher heat resistance than Spiro-OMeTAD, even when the combination of the charge transport material and the electron-accepting dopant was reversed. While the reason for this high heat resistance is unclear, it is possible that the molecular structure of the charge transport composition contributes. It has been suggested that the deterioration of Spiro-OMeTAD properties due to changes in molecular crystallinity during heat resistance testing at temperatures above 80°C is the cause (non-patent document: ACS Appl. Mater. Interfaces 2021, 13, 37, 44294-44301). It is believed that the charge transport composition of the present invention has a planar structure and long π-conjugation, and that the high intermolecular packing makes it easy to maintain crystallinity even at high temperatures, thereby exhibiting good heat resistance.

Claims

1. A charge transport composition for forming a charge transport thin film in an organic photoelectric conversion element, comprising a charge transport substance represented by the following formula (1), an electron-accepting dopant substance, and an organic solvent: [(wherein, R 1 each independently represents a hydrogen atom, an aromatic hydrocarbon group which may have a substituent, a tert-butoxycarbonyl group, or a silyl group substituted with an alkyl group or an aromatic hydrocarbon group; R 2 each independently represents any one of groups represented by the following formulas [B1] to [B11]. (In the formula, R 3 ~R 23 , R 26 ~R 47 and R 49 ~R 150 each independently represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, or a diphenylamino group, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a heteroaryl group having 2 to 20 carbon atoms, each of which may be substituted with a halogen atom; R 24 and R 25 are, independently of each other, Z 1 R represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, which may be substituted with 48 is a hydrogen atom, Z 4 an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an alkynyl group having 2 to 20 carbon atoms, which may be substituted with Z 1 Ar represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, which may be substituted with 1 each independently represents an aryl group having 6 to 20 carbon atoms which may be substituted with a di(aryl group having 6 to 20 carbon atoms)amino group; Z 1 is a halogen atom, a nitro group, a cyano group, or Z 2 represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms, each of which may be substituted with 2 is a halogen atom, a nitro group, a cyano group, or Z 3 Z represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, each of which may be substituted with 3 represents a halogen atom, a nitro group or a cyano group; Z 4 is a halogen atom, a nitro group, a cyano group, or Z 5 Z represents an aryl group having 6 to 20 carbon atoms or a heteroaryl group having 2 to 20 carbon atoms, each of which may be substituted with 5 is a halogen atom, a nitro group, a cyano group, or Z 3 represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an alkynyl group having 2 to 20 carbon atoms, each of which may be substituted with one of the following:

2. The charge transporting composition according to claim 1, wherein the electron-accepting dopant substance is a salt consisting of an anion represented by the following formula (An1) and its counter cation, or a borane compound represented by the following formula (Bo1). (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, Ar b1 ~Ar b3 each independently represents an aromatic hydrocarbon group which may have a substituent or an aromatic heterocyclic group which may have a substituent.

3. The charge transporting composition according to claim 2, wherein said salt is an onium salt.

4. The charge transporting composition according to claim 2, wherein the anion represented by the formula (An1) is represented by the following formula [an1]:

5. The charge transporting composition according to claim 1, wherein the content of said electron accepting dopant substance is 0.001 to 50 parts by mass per 1 part of the charge transporting substance.

6. The above R 1 and each independently represent an aromatic hydrocarbon group which may have a substituent, a tert-butoxycarbonyl group, or a silyl group substituted with an alkyl group or an aromatic hydrocarbon group.

7. The above R 2 2. The charge transport composition according to claim 1, wherein each of the groups independently represents a group represented by formula [B1] or [B4].

8. The above R 2 8. The charge transporting composition according to claim 7, wherein is a group represented by formula [B1].

9. The charge transporting composition according to any one of claims 1 to 8, which is used for a hole collecting layer of a perovskite photoelectric conversion element.

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

11. The charge transporting thin film according to claim 10, which is a hole collecting layer of a perovskite photoelectric conversion element.

12. A perovskite photoelectric conversion device comprising the charge transport thin film according to claim 11.

13. The perovskite photoelectric conversion element according to claim 12, which is of a normal stacking type.

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

15. 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.

16. A compound represented by the following formula (X): (In the formula, R a are each independently a halogen atom or an alkoxy group having 1 to 6 carbon atoms; R b are each independently a hydrogen atom or a fluorine atom.

17. The compound according to claim 16, which is represented by the following formula (X-1) or (X-2):

Images