Compound having sulfonate group, and photoelectric conversion element using said compound

Abstract

The present invention provides: a compound which is useful as a hole transport material for photoelectric conversion elements, and which is represented by general formula (1); and a photoelectric conversion element which uses this compound in a hole transport layer.

Description

Compound having sulfonate group and photoelectric conversion element using said compound

[0001] The present invention relates to a compound having a sulfonate group, and a photoelectric conversion element and a perovskite solar cell using the compound.

[0002] In recent years, solar power generation has attracted attention as a clean energy source, and the development of solar cells has been actively pursued. Among these, the development of solar cells using perovskite materials in the photoelectric conversion layer (hereinafter referred to as perovskite solar cells) has attracted attention as a next-generation solar cell that can be manufactured at low cost using a solution process (for example, Patent Document 1, Non-Patent Documents 1 and 2).

[0003] Perovskite solar cells often use hole transport materials in their devices. The purposes of their use include (1) improving photoelectric conversion efficiency and (2) protecting perovskite materials, which are susceptible to the effects of moisture and oxygen (see, for example, Non-Patent Document 3). Spiro-OMeTAD is often used as a standard hole transport material, and there have been few reports of hole transport materials that contribute more significantly to photoelectric conversion properties than this material.

[0004] When a hole transport material is used in a perovskite solar cell element, a dopant is added to the hole transport material in a conventional method for fabricating an element using an organic compound as the hole transport material. This dopant is used to reduce the electrical resistance of the hole transport material (e.g., Non-Patent Documents 3 and 4).

[0005] However, the use of dopants as additives not only complicates the manufacturing process but also increases manufacturing costs. Furthermore, it has been reported that dopants promote moisture absorption, corrode the photoelectric conversion layer, and deteriorate the hole transport layer due to volatilization, which leads to a decrease in device characteristics (e.g., Non-Patent Document 5). Therefore, there is a need for the development of a photoelectric conversion element that has a dopant-free hole transport layer and exhibits high photoelectric conversion characteristics and durability. On the other hand, there are cases where the use of dopants is unavoidable in order to achieve good photoelectric conversion efficiency. Therefore, there is also a need for the development of a photoelectric conversion element that contains dopants but exhibits minimal deterioration in device characteristics over time.

[0006] International Publication No. 2017 / 104792

[0007] J. Am. Chem. Soc., 2009, Vol. 131, pp. 6050-6051 Science, 2012, Vol. 388, pp. 643-647 Chem. Sci., 2019, 10, pp. 6748-6769 Adv. Funct. Mater., 29, 24, 2019, 1901296 J. Am. Chem. Soc., 2018, 140, 48, 16720-16730

[0008] The problem to be solved by the present invention is to provide a compound useful as a hole transport material for a photoelectric conversion element that does not contain a dopant as an additive, and a photoelectric conversion element and a perovskite solar cell that use the compound in a hole transport layer and have good photoelectric conversion characteristics. Another problem to be solved by the present invention is to provide a compound useful as a hole transport material for a photoelectric conversion element that contains a dopant but exhibits little deterioration in the element characteristics over time.

[0009] In order to solve the above problems, the inventors have conducted extensive research into improving photoelectric conversion properties and have found that a highly efficient photoelectric conversion element and perovskite solar cell can be obtained by using a compound having a specific structure as a hole transport layer.

[0010] 1. A compound represented by the following general formula (1):

[0011]

[0012] [In the formula, R １is an optionally substituted linear or branched alkyl group having 1 to 18 carbon atoms, an optionally substituted linear or branched alkenyl group having 2 to 20 carbon atoms, an optionally substituted linear or branched alkynyl group having 2 to 20 carbon atoms, a optionally substituted cycloalkyl group having 3 to 12 carbon atoms, an optionally substituted aromatic hydrocarbon group having 6 to 36 carbon atoms, or a optionally substituted heterocyclic group having 5 to 36 ring atoms, and X represents a monovalent cation other than a hydrogen ion. ２ ~R ９ each independently represents a hydrogen atom, a linear or branched alkyl group of 1 to 18 carbon atoms which may have a substituent, a linear or branched alkenyl group of 2 to 20 carbon atoms which may have a substituent, a linear or branched alkynyl group of 2 to 20 carbon atoms which may have a substituent, a cycloalkyl group of 3 to 12 carbon atoms which may have a substituent, a linear or branched alkoxy group of 1 to 20 carbon atoms which may have a substituent, a cycloalkoxy group of 3 to 10 carbon atoms which may have a substituent, a linear or branched alkoxycarbonyl group of 1 to 18 carbon atoms which may have a substituent, a thio group of 1 to 18 carbon atoms which may have a substituent, an amino group of 1 to 20 carbon atoms which may have a substituent, an aromatic hydrocarbon group of 6 to 36 carbon atoms which may have a substituent, or a heterocyclic group of 5 to 36 ring atoms which may have a substituent.]

[0013] 2. In the general formula (1), R １ is a linear or branched alkyl group having 1 to 18 carbon atoms which may have a substituent.

[0014] 3. In the general formula (1), R ２ ~R ９ and at least one of the above is an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent or an amino group having 1 to 20 carbon atoms which may have a substituent.

[0015] 4. The compound according to any one of the above 1 to 3, wherein in the general formula (1), X is an alkali metal ion or an ammonium ion which may have a substituent.

[0016] 5. The compound according to 4 above, wherein in the general formula (1), the alkali metal ion is at least one selected from the group consisting of a sodium ion, a potassium ion, a rubidium ion, and a cesium ion.

[0017] 6. A hole transport material comprising the compound according to any one of 1 to 5 above.

[0018] 7. A hole transport material composition for a photoelectric conversion element, comprising the hole transport material according to 6 above.

[0019] 8. A photoelectric conversion element using the hole transport material composition for photoelectric conversion according to 7 above.

[0020] According to the compound having a sulfonate group according to the present invention and the hole transport layer using the compound, by using the compound between the photoelectric conversion layer and the electrode, it is possible to obtain a photoelectric conversion element and a perovskite solar cell having good photoelectric conversion efficiency.

[0021] 1A and 1B are schematic cross-sectional views illustrating the configurations of photoelectric conversion elements according to examples of the present invention and comparative examples.

[0022] DETAILED DESCRIPTION OF THE INVENTION The hole transport layer of the present invention is used in a photoelectric conversion element and a perovskite-type photoelectric conversion element.

[0023] The compounds represented by formula (1) will be specifically described below, but the present invention is not limited thereto.

[0024] In general formula (1), R １represents a linear or branched alkyl group having 1 to 18 carbon atoms which may have a substituent, a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent, a linear or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent, a cycloalkyl group having 3 to 12 carbon atoms which may have a substituent, an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or a heterocyclic group having 5 to 36 ring atoms which may have a substituent.

[0025] In general formula (1), R １ Specific examples of the "straight-chain or branched alkyl group having 1 to 18 carbon atoms" in the "straight-chain or branched alkyl group having 1 to 18 carbon atoms which may have a substituent" represented by the formula (1) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an s-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, an n-hexyl group, a 2-ethylhexyl group, a heptyl group, an octyl group, an isooctyl group, a nonyl group, and a decyl group. １ In the above, one of the hydrogen atoms of the substituents is a sulfonate group (—SO ３ X).

[0026] In general formula (1), R １ Specific examples of the "straight-chain or branched alkenyl group having 2 to 20 carbon atoms" in the "straight-chain or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent" represented by the formula (I) include a vinyl group, a 1-propenyl group, an allyl group, a 1-butenyl group, a 2-butenyl group, a 1-pentenyl group, a 1-hexenyl group, an isopropenyl group, an isobutenyl group, and a straight-chain or branched alkenyl group having 2 to 20 carbon atoms in which a plurality of these alkenyl groups are bonded, and R １ In the above, one of the hydrogen atoms of the substituents is a sulfonate group (—SO ３ X).

[0027] In general formula (1), R １Specific examples of the "straight-chain or branched alkynyl group having 2 to 20 carbon atoms" in the "straight-chain or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent" represented by the formula (I) include an ethynyl group, a 1-propynyl group, a 2-propynyl group, a 1-butynyl group, a 2-butynyl group, a 1-methyl-2-propynyl group, a 1-pentynyl group, a 2-pentynyl group, a 1-methyl-n-butynyl group, a 2-methyl-n-butynyl group, a 3-methyl-n-butynyl group, and a 1-hexynyl group, and the like can be given. １ In the above, one of the hydrogen atoms of the substituents is a sulfonate group (—SO ３ X).

[0028] In general formula (1), R １ Specific examples of the "cycloalkyl group having 3 to 12 carbon atoms" in the "cycloalkyl group having 3 to 12 carbon atoms which may have a substituent" represented by the formula (I) include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclodecyl group, and a cyclododecyl group. １ In the above, one of the hydrogen atoms of the substituents is a sulfonate group (—SO ３ X).

[0029] In general formula (1), R １ Specific examples of the "aromatic hydrocarbon group having 6 to 36 carbon atoms" in the "aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent" represented by the formula (I) include a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a biphenyl group, an anthracenyl group (anthryl group), a phenanthryl group, a fluorenyl group, an indenyl group, a pyrenyl group, a perylenyl group, a fluoranthenyl group, and a triphenylenyl group, and R １ In the above, one of the hydrogen atoms of the substituents is a sulfonate group (—SO ３ In the present invention, the aromatic hydrocarbon group includes a "condensed polycyclic aromatic group."

[0030] In general formula (1), R １Specific examples of the "heterocyclic group having 5 to 36 ring atoms" in the "heterocyclic group having 5 to 36 ring atoms which may have a substituent" represented by the formula (I) include a pyridyl group, a pyrimidinyl group, a triazinyl group, a thienyl group, a furyl group (furanyl group), a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a triazolyl group, a quinolyl group, an isoquinolyl group, a naphthyldinyl group, an acridinyl group, a phenanthrolinyl group, a benzofuranyl group, a benzothienyl group, an oxazolyl group, an indolyl group, a carbazolyl group, a benzoxazolyl group, a thiazolyl group, a benzothiazolyl group, a quinoxalinyl group, a benzimidazolyl group, a pyrazolyl group, a dibenzofuranyl group, a dibenzothienyl group, and a carbonylyl group. １ In the above, one of the hydrogen atoms of the substituents is a sulfonate group (—SO ３ X).

[0031] In general formula (1), R １Examples of the "substituent" in the "optionally substituted linear or branched alkyl group having 1 to 18 carbon atoms," "optionally substituted linear or branched alkenyl group having 2 to 20 carbon atoms," "optionally substituted linear or branched alkynyl group having 2 to 20 carbon atoms," "optionally substituted cycloalkyl group having 3 to 12 carbon atoms," "optionally substituted aromatic hydrocarbon group having 6 to 36 carbon atoms," or "optionally substituted heterocyclic group having 5 to 36 ring atoms," represented by the above formula (I) specifically include: a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom; a cyano group; a hydroxyl group; a nitro group; a nitroso group; a carboxyl group; a phosphate group; a carboxylic acid ester group such as a methyl ester group or an ethyl ester group; linear or branched alkyl groups having 1 to 18 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-pentyl, isopentyl, n-hexyl, 2-ethylhexyl, heptyl, octyl, isooctyl, nonyl, and decyl; linear or branched alkenyl groups having 2 to 20 carbon atoms, such as vinyl, 1-propenyl, allyl, 1-butenyl, 2-butenyl, 1-pentenyl, 1-hexenyl, isopropenyl, and isobutenyl; linear or branched alkoxy groups having 1 to 18 carbon atoms, such as methoxy, ethoxy, propoxy, t-butoxy, pentyloxy, and hexyloxy; aromatic hydrocarbon groups having 6 to 30 carbon atoms, such as a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, or a pyrenyl group; heterocyclic groups having 5 to 30 ring atoms, such as a pyridyl group, a pyrimidinyl group, a triazinyl group, a thienyl group, a furyl group (a furanyl group), a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a triazolyl group, a quinolyl group, an isoquinolyl group, a naphthyldinyl group, an acridinyl group, a phenanthrolinyl group, a benzofuranyl group, a benzothienyl group, an oxazolyl group, an indolyl group, a carbazolyl group, a benzoxazolyl group, a thiazolyl group, a benzothiazolyl group, a quinoxalinyl group, a benzimidazolyl group, a pyrazolyl group, a dibenzofuranyl group, a dibenzothienyl group, or a carbonyl group;Unsubstituted amino group (—NH; ２ Examples of the substituents include: amino groups having 0 to 18 carbon atoms, such as mono-substituted amino groups such as ethylamino, acetylamino, and phenylamino, or di-substituted amino groups such as diethylamino, diphenylamino, and acetylphenylamino; thio groups having 0 to 18 carbon atoms, such as unsubstituted thio groups (thiol groups: —SH), methylthio, ethylthio, propylthio, hex-5-ene-3-thio, phenylthio, and biphenylthio; and the like. These "substituents" may be contained alone or in combination, and when multiple substituents are contained, they may be the same or different. Furthermore, these "substituents" may further have the substituents exemplified above.

[0032] In general formula (1), R １ sulfonate group (―SO ３ X in X) represents a monovalent cation other than a hydrogen ion. Specifically, the monovalent cation is preferably an alkali metal ion, an ammonium ion which may have a substituent, or a phosphonium ion which may have a substituent, more preferably an alkali metal ion or an ammonium ion which may have a substituent, and particularly preferably an alkali metal ion, but is not limited to these.

[0033] Specific examples of alkali metals include lithium ions, sodium ions, potassium ions, rubidium ions, cesium ions, and francium ions, and it is preferable that the alkali metal be at least one selected from the group consisting of sodium ions, potassium ions, rubidium ions, and cesium ions.

[0034] Specific examples of the ammonium ion which may have a substituent include a methylammonium ion, a methylammonium monofluoride ion, a methylammonium difluoride ion, a methylammonium trifluoride 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, an imidazolium ion, a tri-n-butylammonium ion, and a tetra-n-butylammonium ion.

[0035] In general formula (1), R １ is preferably a linear or branched alkyl group having 1 to 18 carbon atoms which may have a substituent. １ is more preferably an alkyl group having a total of 18 or less carbon atoms including substituents, even more preferably an alkyl group having a total of 10 or less carbon atoms including substituents, and particularly preferably an alkyl group having a total of 6 or less carbon atoms including substituents.

[0036] In general formula (1), R ２ ~R ９each independently represents a hydrogen atom, a linear or branched alkyl group of 1 to 18 carbon atoms which may have a substituent, a linear or branched alkenyl group of 2 to 20 carbon atoms which may have a substituent, a linear or branched alkynyl group of 2 to 20 carbon atoms which may have a substituent, a cycloalkyl group of 3 to 12 carbon atoms which may have a substituent, a linear or branched alkoxy group of 1 to 20 carbon atoms which may have a substituent, a cycloalkoxy group of 3 to 10 carbon atoms which may have a substituent, a linear or branched alkoxycarbonyl group of 1 to 18 carbon atoms which may have a substituent, a thio group of 1 to 18 carbon atoms which may have a substituent, an amino group of 1 to 20 carbon atoms which may have a substituent, an aromatic hydrocarbon group of 6 to 36 carbon atoms which may have a substituent, or a heterocyclic group of 5 to 36 ring atoms which may have a substituent.

[0037] In general formula (1), R ２ ~R ９ In the "straight-chain or branched alkyl group having 1 to 18 carbon atoms which may have a substituent" represented by the formula (1), the "straight-chain or branched alkyl group having 1 to 18 carbon atoms" is, for example, １ Examples of the alkyl group include the same as the "straight-chain or branched alkyl group having 1 to 18 carbon atoms which may have a substituent" represented by the following formula:

[0038] In general formula (1), R ２ ~R ９ The "straight-chain or branched alkenyl group having 2 to 20 carbon atoms" in the "straight-chain or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent" represented by the general formula (1) includes R １ Examples of the alkenyl group include the same as the "straight-chain or branched alkenyl group having 2 to 20 carbon atoms" represented by the following formula:

[0039] In general formula (1), R ２ ~R ９The "straight-chain or branched alkynyl group having 2 to 20 carbon atoms" in the "straight-chain or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent" represented by the general formula (1) includes R １ Examples of the alkynyl group include the same as the "straight-chain or branched alkynyl group having 2 to 20 carbon atoms" represented by the following formula:

[0040] In general formula (1), R ２ ~R ９ The "cycloalkyl group having 3 to 12 carbon atoms" in the "cycloalkyl group having 3 to 12 carbon atoms which may have a substituent" represented by the general formula (1) is, for example, R １ Examples thereof include the same as the "cycloalkyl group having 3 to 12 carbon atoms" represented by the following formula:

[0041] In general formula (1), R ２ ~R ９ Specific examples of the "straight-chain or branched alkoxy group having 1 to 20 carbon atoms" in the "straight-chain or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent" represented by the formula (1) include a methoxy group, an ethoxy group, a propoxy group, an n-butoxy group, an n-pentyloxy group, an n-hexyloxy group, a heptyloxy group, an octyloxy group, a nonyloxy group, a decyloxy group, an isopropoxy group, an isobutoxy group, an s-butoxy group, a t-butoxy group, an isooctyloxy group, a t-octyloxy group, a phenoxy group, a tolyloxy group, a biphenylyloxy group, a terphenylyloxy group, a naphthyloxy group, an anthryloxy group, a phenanthryloxy group, a fluorenyloxy group, an indenyloxy group, and the like.

[0042] In general formula (1), R ２ ~R ９ Specific examples of the "straight-chain or branched cycloalkoxy group having 3 to 10 carbon atoms" in the "optionally substituted straight-chain or branched cycloalkoxy group having 3 to 10 carbon atoms" represented by the formula (1) include a cyclopropoxy group, a cyclobutoxy group, a cyclopentyloxy group, and a cyclohexyloxy group.

[0043] In general formula (1), R ２ ~R ９ Specific examples of the "alkoxycarbonyl group having 1 to 18 carbon atoms" in the "linear or branched alkoxycarbonyl group having 1 to 18 carbon atoms which may have a substituent" represented by the formula (1) include a methoxycarbonyl group, an ethoxycarbonyl group, etc.

[0044] In general formula (1), R ２ ~R ９ Specific examples of the "thio group having 1 to 18 carbon atoms" in the "thio group having 1 to 18 carbon atoms which may have a substituent" represented by the formula (1) include a methylthio group, an ethylthio group, a propylthio group, a phenylthio group, and a biphenylthio group.

[0045] In general formula (1), R ２ ~R ９ Specific examples of the "amino group having 1 to 20 carbon atoms" in the "amino group having 1 to 20 carbon atoms which may have a substituent" represented by the formula (1) include monosubstituted amino groups such as an ethylamino group, an acetylamino group, and a phenylamino group, and disubstituted amino groups such as a diethylamino group, a diphenylamino group, and an acetylphenylamino group.

[0046] In general formula (1), R ２ ~R ９ The "aromatic hydrocarbon group having 6 to 36 carbon atoms" in the "aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent" represented by the general formula (1) is, for example, R １ Examples of the aromatic hydrocarbon group include the same as the "optionally substituted aromatic hydrocarbon group having 6 to 36 carbon atoms" represented by the following formula:

[0047] In general formula (1), R ２ ~R ９ The "heterocyclic group having 5 to 36 ring atoms" in the "heterocyclic group having 5 to 36 ring atoms which may have a substituent" represented by the formula (1) is, for example, a heterocyclic group having 5 to 36 ring atoms which may have a substituent, represented by the formula (1), １ Examples of the heterocyclic group include the same as the "heterocyclic group having 5 to 36 ring atoms which may have a substituent" represented by the following formula:

[0048] In general formula (1), R ２ ~R ９ Examples of the "substituent" in "a linear or branched alkyl group having 1 to 18 carbon atoms which may have a substituent", "a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent", "a linear or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent", "a cycloalkyl group having 3 to 12 carbon atoms which may have a substituent", "a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent", "a cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent", "a linear or branched alkoxycarbonyl group having 1 to 18 carbon atoms which may have a substituent", "a thio group having 1 to 18 carbon atoms which may have a substituent", "an amino group having 1 to 20 carbon atoms which may have a substituent", "an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent" or "a heterocyclic group having 5 to 36 ring atoms which may have a substituent" represented by the general formula (1) include R １ Examples of the alkyl group include the "straight-chain or branched alkyl group having 1 to 18 carbon atoms which may have a substituent" represented by the following formula:

[0049] In general formula (1), R ２ ~R ９ Among these, at least one is preferably an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or an amino group having 1 to 20 carbon atoms which may have a substituent. ２ ~R ９ It is more preferable that at least two of the R groups be aromatic hydrocarbon groups having 6 to 36 carbon atoms which may have a substituent or amino groups having 1 to 20 carbon atoms which may have a substituent. ３ and R ８ are each an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or an amino group having 1 to 20 carbon atoms which may have a substituent, or R ４ and R ７are each preferably an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or an amino group having 1 to 20 carbon atoms which may have a substituent. ２ , R ４ ~R ７ and R ９ , or the remaining R ２ , R ３ , R ５ , R ６ , R ８ and R ９ is preferably a hydrogen atom. ３ and R ８ are each an optionally substituted diphenylamino group, or an aromatic hydrocarbon group having 6 to 36 carbon atoms substituted by an optionally substituted diphenylamino group or a carbazole group, or R ４ and R ７ are each preferably an optionally substituted diphenylamino group, or an aromatic hydrocarbon group having 6 to 36 carbon atoms substituted with an optionally substituted diphenylamino group or a carbazole group. ２ , R ４ ~R ７ and R ９ , or the remaining R ２ , R ３ , R ５ , R ６ , R ８ and R ９ is preferably a hydrogen atom. ３ and R ８ or R ４ and R ７ The total number of carbon atoms including the substituents is preferably 50 or less, more preferably 40 or less, and even more preferably 30 or less.

[0050] Specific examples of the compound represented by the general formula (1) of the present invention are shown below, but the present invention is not limited to these. Furthermore, the following exemplary compounds are shown with some hydrogen atoms, carbon atoms, etc. omitted, and are examples of possible isomers, but all other isomers are included. Furthermore, each may be a mixture of two or more isomers.

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059] The compound of the present invention represented by the general formula (1) can be synthesized by known methods such as those disclosed in Japanese Patent Application No. 2018-135255. As an example, the synthesis of compound (A-1) will be described. Compound (A-1) can be obtained by introducing the corresponding substituent into 3,6-dibromocarbazole by Suzuki-Miyaura coupling reaction or Buchwald reaction, and then reacting with the corresponding sultone. Similarly, the compound represented by the general formula (1) can be obtained by known methods using a halogenated carbazole derivative as a precursor.

[0060] The compound of the present invention represented by the general formula (1) can be purified by column chromatography, adsorption purification using silica gel, activated carbon, activated clay, or the like, recrystallization or crystallization using a solvent, or the like. Alternatively, it is effective to use a compound with increased purity by combining these methods. Furthermore, these compounds can be identified by nuclear magnetic resonance analysis (NMR).

[0061] The compound of the present invention represented by the general formula (1) can be used as a hole transport material contained in a hole transport layer for organic electronic devices such as photoelectric conversion elements and organic EL elements.

[0062] Preferred embodiments of the photoelectric conversion element of the present invention will be described below.

[0063] <Photoelectric Conversion Element> As shown in the schematic cross-sectional view of Fig. 1, the photoelectric conversion element of the present invention typically has a conductive support 1, an electron transport layer 2, a photoelectric conversion layer 3, a hole transport layer 4, and a counter electrode 5. In addition, a multilayer structure in which a hole transport layer is inserted between the photoelectric conversion layer 3 and the hole transport layer 4 for the purpose of preventing diffusion of a dopant may also be used.

[0064] As shown in FIG. 1 , the photoelectric conversion element of the present invention preferably comprises a conductive support 1, an electron transport layer 2, a photoelectric conversion layer 3, a hole transport layer 4, and a counter electrode 5, but is not limited thereto. Furthermore, the photoelectric conversion element of the present invention is preferably used as a solar cell, and is more preferably a perovskite-type photoelectric conversion element, but is not limited thereto. In the present invention, the perovskite-type photoelectric conversion element preferably comprises a conductive support (electrode) 1, an electron transport layer 2, a photoelectric conversion layer (perovskite layer) 3, a hole transport layer 4, and a counter electrode 5, in this order. Alternatively, the photoelectric conversion element may be configured in the order of the conductive support, the hole transport layer, the photoelectric conversion layer (perovskite layer), the electron transport layer, and the counter electrode.

[0065] <Conductive Support> In the photoelectric conversion element of the present invention, the conductive support 1 shown in FIG. 1 must be translucent enough to transmit light that contributes to photoelectric conversion. In addition, the conductive support is preferably a conductive substrate because it is a member that has the function of extracting current from the photoelectric conversion layer. Specific examples of conductive materials include tin-doped indium oxide (ITO), zinc-doped indium oxide (IZO), tungsten-doped indium oxide (IWO), zinc aluminum oxide (AZO), fluorine-doped tin oxide (FTO), indium oxide (In ２ O ３), and conductive transparent oxide semiconductors such as indium-tin composite oxide, among which tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), and the like are preferably used.

[0066] 1 is a layer located between the conductive support 1 and the photoelectric conversion layer (perovskite layer) 3, and is preferably, but not particularly limited to, formed on the conductive support 1. The electron transport layer is used to improve the efficiency of electron transfer from the photoelectric conversion layer to the electrode and to block the transfer of holes.

[0067] In the present invention, specific examples of the semiconductor that forms the electron transport layer include tin oxide (SnO, SnO ２ , SnO ３ etc.), titanium oxide (TiO ２ etc.), tungsten oxide (WO ２ , W.O. ３ , W ２ O ３ etc.), zinc oxide (ZnO), niobium oxide (Nb ２ O ５ etc.), tantalum oxide (Ta ２ O ５ etc.), yttrium oxide (Y ２ O ３ etc.), strontium titanate (SrTiO ３ Examples of the semiconductor include metal oxides such as titanium sulfide, zinc sulfide, zirconium sulfide, copper sulfide, tin sulfide, indium sulfide, tungsten sulfide, cadmium sulfide, and silver sulfide; metal selenides such as titanium selenide, zirconium selenide, indium selenide, and tungsten selenide; and elemental semiconductors such as silicon and germanium, and it is preferable to use one or more of these semiconductors. In the present invention, it is preferable to use one or more of tin oxide, titanium oxide, and zinc oxide as the semiconductor.

[0068] In the present invention, the paste containing the semiconductor fine particles may be a commercially available product, or a paste (electron transport layer coating liquid) prepared by dispersing commercially available semiconductor fine powder in a solvent may be used. Specific examples of solvents used in preparing the paste include, but are not limited to, water; alcohol-based solvents such as methanol, ethanol, and isopropyl alcohol; ketone-based solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; and hydrocarbon solvents such as n-hexane, cyclohexane, benzene, and toluene. These solvents may be used alone or in combination.

[0069] In the present invention, the semiconductor fine powder may be dispersed in a solvent after grinding the powder in a mortar or the like, or a dispersing machine such as a ball mill, a paint conditioner, a vertical bead mill, a horizontal bead mill, or an attritor may be used. When preparing a paste, it is preferable to add a surfactant or the like to prevent aggregation of the semiconductor fine particles, and it is also preferable to add a thickener such as polyethylene glycol to increase the viscosity.

[0070] In the present invention, the electron transport layer can be obtained using a known film-forming method depending on the material to be formed. The electron transport layer can be formed by any coating method using a coating liquid. Examples of the method include, but are not limited to, a wet coating method such as spin coating, inkjet printing, doctor blade printing, drop casting, squeegee printing, screen printing, reverse roll coating, gravure coating, kiss coating, roll brushing, spray coating, air knife coating, wire barber coating, pipe doctor printing, impregnation / coating, or curtain coating, followed by baking to remove solvents and additives, as well as sputtering, vapor deposition, electrodeposition, electrodeposition, and microwave irradiation. In the present invention, it is preferable to form a film by spin coating using the electron transport layer coating liquid prepared by the above method, but this is not limiting. The spin coating conditions can be appropriately set. The atmosphere in which the film is formed is not particularly limited, and the film may be formed in air.

[0071] When a dense electron transport layer is used, the thickness of the electron transport layer is preferably 5 nm to 100 nm, more preferably 10 nm to 50 nm, from the viewpoint of further improving photoelectric conversion efficiency. In the present invention, when a porous (mesoporous) metal oxide is used in addition to the dense layer, the thickness of the electron transport layer is preferably 20 to 200 nm, more preferably 50 to 150 nm.

[0072] <Photoelectric Conversion Layer> In the photoelectric conversion element of the present invention, a photoelectric conversion layer (perovskite layer) 3 is preferably formed on the electron transport layer 2 shown in FIG.

[0073] In the present invention, when used as a perovskite photoelectric conversion element, the perovskite material of the photoelectric conversion layer is a perovskite material represented by the general formula ABX ３ Here, A, B, and X represent an organic cation or a monovalent metal cation, a metal cation, and a halide anion, respectively. For example, A=K ＋ , Rb ＋ , Cs ＋ , C.H. ３ NH ３ ＋ (hereinafter, MA: methylammonium), NH=CHNH ２ ＋ (hereinafter referred to as FA: Formamidinium), CH ３ CH ２ NH ３ ＋ (hereinafter, EA: ethylammonium); B = Pb, Sn; X = I － ,Br － More specifically, MAPbI ３ , FAPbI ３ , EAPbI ３ , CsPbI ３ , MASnI ３ , FASnI ３ , EASnI ３ , MAPbBr ３ , FAPbBr ３ , EAPbBr ３ , MASnBr３ , FASnBr ３ , EASnBr ３ and (FAMA)Pb(IBr) ３ , K(FAMA)Pb(IBr) ３ , Rb(FAMA)Pb(IBr) ３ , Cs(FAMA)Pb(IBr) ３ The layer may contain a perovskite material having a mixed cation and mixed anion represented by any of the following compositions, but is not limited to these. It is preferable to use one or more of these perovskite materials. In addition, the layer may contain a light absorber other than the perovskite material.

[0074] As a method for coating the photoelectric conversion layer (perovskite layer) of the photoelectric conversion element of the present invention with a coating liquid, any coating method can be used, and examples thereof include the same methods as those for forming the electron transport layer.

[0075] The perovskite precursor may be a commercially available material, and in the present invention, it is preferable to use a precursor consisting of lead halide, methylammonium halide, formamidine halide, or cesium halide in any composition, but the present invention is not limited to this.

[0076] From the viewpoint of precursor solubility, examples of the solvent for the perovskite precursor solution of the present invention include, but are not limited to, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), γ-butyrolactone, etc. Furthermore, these solvents may be used alone or in combination of two or more, and it is preferable to use a mixed solution of N,N-dimethylformamide and dimethyl sulfoxide.

[0077] In the present invention, the atmosphere during deposition of the photoelectric conversion layer (perovskite layer) is preferably a dry atmosphere, more preferably a dry inert gas atmosphere such as a glove box, from the viewpoint of preventing moisture contamination and enabling the reproducible production of highly efficient perovskite solar cells. It is also preferable to dehydrate the layer using a molecular sieve or the like and use a solvent with a low moisture content.

[0078] In the present invention, the temperature at which the photoelectric conversion layer (perovskite layer) is heated using a hot plate or the like is preferably 50 to 200° C., more preferably 70 to 150° C., from the viewpoint of producing a perovskite material from the precursor. The heating time is preferably about 10 to 90 minutes, more preferably about 10 to 60 minutes.

[0079] The film thickness of the photoelectric conversion layer (perovskite layer) of the present invention is preferably 50 to 1000 nm, more preferably 300 to 700 nm, from the viewpoint of further suppressing performance degradation due to defects and peeling, and in order to ensure that the photoelectric conversion layer has sufficient light absorptivity and prevent the device resistance from becoming too high.

[0080] <Hole Transport Layer> In the photoelectric conversion element of the present invention, the hole transport layer 4 shown in FIG. 1 is a layer having the function of transporting holes, and is a layer located between the photoelectric conversion layer (perovskite layer) 3 and the counter electrode 5. The hole transport layer is used to improve the efficiency of hole transfer from the photoelectric conversion layer to the electrode and to block the transfer of electrons. For example, a conductor, a semiconductor, an organic hole transport material, etc. can be used for the hole transport layer, and an additive may be contained for the purpose of further improving the hole transport properties. It is desirable to reduce the amount of additive used in the hole transport layer, and the photoelectric conversion element of the present invention has high characteristics even without an additive in the hole transport layer.

[0081] The hole transport layer of the present invention is a layer containing the compound represented by the general formula (1) as a hole transport material. The hole transport layer of the present invention may contain one or more compounds represented by the general formula (1), and may also contain other hole transport materials not belonging to the present invention. Even in a multilayer structure using a layer (hereinafter also referred to as an intermediate layer) in which a hole transport layer is inserted between the photoelectric conversion layer and the hole transport layer for the purpose of preventing dopant diffusion, the intermediate layer may contain the compound represented by the general formula (1), and a hole transport material not belonging to the present invention may also be used as the hole transport layer.

[0082] Specific examples of hole transport materials other than those of the hole transport material of the present invention include CuI and CuInSe. ２Compound semiconductors containing monovalent copper such as CuS; GaP, NiO, CoO, FeO, Bi ２ O ３ , MoO ２ , Cr ２ O ３ Examples of the organic hole transport material include compounds containing metals other than copper, such as copper oxides, and the like. These metal oxides may be mixed into the hole transport layer or may be laminated on the hole transport material. Examples of the organic hole transport material include polythiophene derivatives such as poly-3-hexylthiophene (P3HT) and polyethylenedioxythiophene (PEDOT), fluorene derivatives such as 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (Spiro-OMeTAD), carbazole derivatives such as polyvinylcarbazole, triphenylamine derivatives such as poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), diphenylamine derivatives, polysilane derivatives, and polyaniline derivatives.

[0083] As a method for coating the hole transport layer of the photoelectric conversion element of the present invention with a coating liquid, any coating method can be used, and the same methods as those for forming the electron transport layer can be used.

[0084] In the present invention, the solvent used in the coating solution for the hole transport layer during film formation may be an aromatic organic solvent such as benzene, toluene, xylene, mesitylene, tetralin (1,2,3,4-tetrahydronaphthalene), monochlorobenzene (chlorobenzene), o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, or nitrobenzene; an alkyl halide organic solvent such as dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2-trichloroethane, or dichloromethane; a nitrile solvent such as benzonitrile or acetonitrile; or a tetrahydrofuran or dioxane. Examples of suitable solvents include, but are not limited to, ether solvents such as ethanol, diisopropyl ether, c-pentyl methyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol monomethyl ether; ester solvents such as ethyl acetate and propylene glycol monomethyl ether acetate; and alcohol solvents such as methanol, isopropanol, n-butanol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, cyclohexanol, and 2-n-butoxyethanol. The above solvents may be used alone or in combination, and the solvent to be used can be selected depending on the structure. It is particularly preferable to use aromatic organic solvents and halogenated alkyl organic solvents.

[0085] In the present invention, the thickness of the hole transport layer is preferably 5 to 500 nm, more preferably 10 to 250 nm, from the viewpoint of further improving the photoelectric conversion efficiency. Even in the case of a multilayer hole transport layer in which a hole transport layer is inserted between the photoelectric conversion layer 4 and the hole transport layer 5 for the purpose of preventing diffusion of the dopant, the total thickness is preferably the same.

[0086] In the present invention, the atmosphere during film formation of the hole transport layer is preferably a dry atmosphere, from the viewpoint of being able to reproducibly produce high-efficiency perovskite solar cells by preventing moisture from being mixed in. Furthermore, it is preferable to use a dehydrated solvent having a moisture content of 10 ppm or less.

[0087] <Additives> In the present invention, the hole transport layer may contain a dopant (or an oxidizing agent) or a basic compound (or a basic additive) as an additive. Incorporating an additive into the hole transport layer to increase the carrier concentration of the hole transport material in the hole transport layer (doping) leads to an improvement in the conversion efficiency of the photoelectric conversion element. In the present invention, when the hole transport layer contains a dopant and a basic additive as additives, the amount of additive is preferably 3.5 equivalents or less per equivalent of the hole transport material. On the other hand, the use of a dopant and a basic additive as additives may complicate the process and increase costs in terms of manufacturing the photoelectric conversion element, and may reduce durability and shorten the element life in terms of characteristics. Therefore, it is desirable to reduce the amount used, but the photoelectric conversion element of the present invention has high characteristics even without the additive.

[0088] In the present invention, when a dopant is contained, specific examples of the dopant include lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), silver bis(trifluoromethanesulfonyl)imide, tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(III)tri[bis(trifluoromethane)sulfonimide] (FK209), and NOSbF. ６ , SbCl ５ , SbF ５ In the present invention, lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) is preferably used, but is not limited to this.

[0089] In the present invention, when a dopant is used, the amount of the dopant is preferably 2.0 equivalents or less, more preferably 0.5 equivalents or less, per equivalent of the hole transport material contained in the hole transport layer.

[0090] In the present invention, a basic compound (basic additive) may be contained as an additive in the hole transport layer. When a basic compound is contained in the present invention, specific examples include 4-tert-butylpyridine (tBP), 2-picoline, and 2,6-lutidine. A basic compound is often used in combination with a dopant. In the present invention, it is also desirable to use a basic compound in combination with a dopant, and it is preferable to use tert-butylpyridine.

[0091] In the present invention, when a basic compound is used, it is preferably used in an amount of 5 equivalents or less, more preferably 3 equivalents or less, relative to 1 equivalent of the hole transport material of the present invention.

[0092] 1 is disposed opposite the conductive support 1 and formed on the hole transport layer 4, thereby enabling exchange of charges with the hole transport layer. In the photoelectric conversion element of the present invention, it is preferable to provide a metal electrode as a counter electrode on the hole transport layer 4, but it is also possible to add an electron blocking layer made of an organic material or an inorganic compound semiconductor between the hole transport layer 4 and the counter electrode 5.

[0093] In the present invention, specific examples of materials used for the counter electrode include metals such as platinum, titanium, stainless steel, aluminum, gold, silver, nickel, magnesium, chromium, cobalt, and copper, or alloys thereof. Among these, it is preferable to use gold, silver, or a silver alloy, as it exhibits high electrical conductivity even in a thin film. Examples of silver alloys include silver-gold alloys, silver-copper alloys, silver-palladium alloys, silver-copper-palladium alloys, and silver-platinum alloys, which are less susceptible to sulfidation or chlorination and improve the stability of the thin film.

[0094] In the present invention, the counter electrode is preferably made of a material that can be formed by a method such as vapor deposition.

[0095] When a metal electrode is used as the counter electrode, the thickness thereof is preferably 10 nm or more, more preferably 50 nm or more, in order to obtain good conductivity.

[0096] In the photoelectric conversion element of the present invention, the conductive support serves as the cathode, and the counter electrode serves as the anode. It is preferable to irradiate light such as sunlight from the conductive support side. When irradiated with sunlight, the photoelectric conversion layer (perovskite layer) absorbs the light and enters an excited state, generating electrons and holes. These electrons move through the electron transport layer, and the holes move through the hole transport layer to the electrode, causing a current to flow, and the element functions as a photoelectric conversion element.

[0097] When evaluating the performance (characteristics) of the photoelectric conversion element of the present invention, the short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency are measured. The short-circuit current density is the current flowing between the output terminals when the output terminals are short-circuited. ２ The open-circuit voltage is the voltage between the output terminals when they are open. The fill factor is the maximum output (product of current and voltage) divided by the product of the short-circuit current density and the open-circuit voltage, and is mainly affected by the internal resistance. The photoelectric conversion efficiency is the ratio of maximum output (W) to 1 cm ２ The value is divided by the light intensity (W) per unit area and multiplied by 100 to obtain a percentage value.

[0098] The photoelectric conversion element of the present invention can be applied to perovskite solar cells, various optical sensors, etc. The perovskite solar cell of the present invention can be obtained by arranging a required number of photoelectric conversion elements, each of which contains a hole transport material containing the compound represented by general formula (1) as a hole transport layer, into modules and providing predetermined electrical wiring.

[0099] Although the preferred embodiment has been described above, the present invention is not limited to this, and may be modified as appropriate within the scope of the present invention.

[0100] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. １ H-NMR (H-NMR (JNM-ECZ400S / L1 nuclear magnetic resonance spectrometer manufactured by JEOL Ltd.)).

[0101] Synthesis Example 1 Synthesis of Compound (A-1) 3,6-Dibromocarbazole (0.65 g, manufactured by TCI), [4-[bis(4-methoxyphenyl)amino]phenyl]boronic acid (1.68 g, manufactured by TCI), 2 M aqueous potassium carbonate solution (10 mL), tetrakistriphenylphosphine palladium (0.06 g, manufactured by Kanto Chemical), and THF (30 mL) were placed in a reaction vessel, and the mixture was degassed under reduced pressure. The mixture was heated under reflux for 6 hours, and upon completion of the reaction, the reaction solution was poured into a beaker containing water (150 mL). Toluene (30 mL) was added, and the layers were separated. The organic layer was dried over magnesium sulfate and then concentrated. The crude product was purified using a silica gel column (toluene:ethyl acetate = 50:1 (volume ratio)) to obtain the compound represented by the following formula (2) as a white solid (yield: 0.85 g, 55%).

[0102] １ H-NMR (400MHz, THF-d ８ ): δ (ppm) = 3.73 (12H), 6.81 (8H), 6.96 (4H), 7.01 (8H), 7.40 (2H), 7.51 (4H), 7.56 (2H), 8.30 (2H), 10.3 (1H).

[0103]

[0104] The compound of formula (2) (0.40 g), sodium hydride (0.03 g, manufactured by Kanto Chemical Co., Inc.), and THF (15 mL) were placed in a reaction vessel and stirred at room temperature for 3 hours. 2,4-butanesultone (0.08 mL, manufactured by TCI) was then added, and the mixture was heated under reflux for 4 hours. The reaction solution was concentrated, dissolved in toluene (60 mL), filtered, and the filtrate was concentrated. The crude product was purified using a silica gel column (ethyl acetate) and then recrystallized (acetone:methanol) to obtain the compound represented by formula (A-1) below as a pale green solid (yield: 0.40 g, 86%).

[0105] １ H-NMR (400MHz, DMSO-d ６ ): δ (ppm) = 1.16 (3H), 1.76 (1H), 2.22 (1H), 2.47 (1H), 3.73 (12H), 4.57 (2H), 6.88-6.95 (12H), 7.04 (8H), 7.63 (4H), 7.70 (4H), 8.48 (2H)

[0106]

[0107] Synthesis Example 2 Synthesis of Compound (A-2) The compound of formula (2) (0.20 g), potassium tert-butoxide (0.06 g, manufactured by Kanto Chemical Co., Inc.), and THF (7 mL) were placed in a reaction vessel and stirred at room temperature for 3 hours. 2,4-butanesultone (0.04 mL, manufactured by TCI) was then added, and the mixture was heated under reflux for 4 hours. The reaction solution was concentrated, dissolved in toluene (30 mL), filtered, and the filtrate was concentrated. The crude product was recrystallized (acetone:methanol) to obtain the compound represented by formula (A-2) below as a milky white solid (yield: 0.15 g, 60%).

[0108] １ H-NMR (400MHz, DMSO-d ６ ): δ (ppm) = 1.16 (3H), 1.76 (1H), 2.22 (1H), 2.40 (1H), 3.75 (12H), 4.58 (2H), 6.89-6.95 (12H), 7.05 (8H), 7.63 (4H), 7.70 (4H), 8.47 (2H)

[0109]

[0110] Synthesis Example 3 Synthesis of Compound (A-3) The compound of formula (2) (0.20 g), cesium carbonate (0.19 g, manufactured by Kanto Chemical Co., Inc.), and THF (7 mL) were placed in a reaction vessel and stirred at room temperature for 3 hours. 2,4-butanesultone (0.04 mL, manufactured by TCI) was then added, and the mixture was heated under reflux for 4 hours. The reaction solution was filtered, washed with THF (20 mL), and then concentrated. This was dissolved in methanol, filtered, and the filtrate was concentrated. The crude product was recrystallized (acetone:ethanol) to obtain the compound represented by formula (A-3) below as a pale green solid (yield: 0.09 g, 33%).

[0111] １ H-NMR (400MHz, DMSO-d ６ ): δ (ppm) = 1.15 (3H), 1.32 (1H), 1.87 (1H), 2.32 (1H), 3.77 (12H), 4.57 (2H), 6.88-6.95 (12H), 7.03 (8H), 7.63 (4H), 7.69 (4H), 8.46 (2H)

[0112]

[0113] Synthesis Example 4 Synthesis of Compound (A-4) The compound of formula (2) (0.20 g), rubidium carbonate (0.13 g, manufactured by Kanto Chemical Co., Inc.), and THF (7 mL) were placed in a reaction vessel and stirred at room temperature for 3 hours. 2,4-butanesultone (0.04 mL, manufactured by TCI) was then added, and the mixture was heated under reflux for 4 hours. The reaction solution was filtered, washed with THF (20 mL), and then concentrated. This was dissolved in methanol, filtered, and the filtrate was concentrated. The crude product was recrystallized (acetone:ethanol) to obtain the compound represented by formula (A-4) below as a pale green solid (yield: 0.07 g, 27%).

[0114] １ H-NMR (400MHz, DMSO-d ６ ): δ (ppm) = 1.16 (3H), 1.44 (1H), 2.15 (1H), 2.33 (1H), 3.73 (12H), 4.57 (2H), 6.88-6.95 (12H), 7.04 (8H), 7.63 (4H), 7.70 (4H), 8.47 (2H)

[0115]

[0116] Synthesis Example 5 Synthesis of Compound (A-5) A compound represented by the following formula (A-5) was obtained as a pale green solid (yield: 0.25 g, 81%) in the same manner as in Synthesis Example 1, except that the compound represented by the above formula (2) was changed to the compound represented by the following formula (3).

[0117] １ H-NMR (400MHz, DMSO-d ６ ): δ (ppm) = 1.18 (3H), 1.79 (1H), 2.23 (1H), 2.46 (1H), 3.65 (12H), 4.57 (2H), 6.81 (8H), 6.85 (8H), 7.10 (2H), 7.50 (2H), 7.79 (2H)

[0118]

[0119] Synthesis Example 6 Synthesis of Compound (A-6) A compound represented by the following formula (A-6) was obtained as a milky white solid (yield: 0.13 g, 63%) in the same manner as in Synthesis Example 2, except that the compound represented by formula (2) was changed to the compound represented by formula (3).

[0120] １ H-NMR (400MHz, DMSO-d ６ ): δ (ppm) = 1.18 (3H), 1.79 (1H), 2.23 (1H), 2.40 (1H), 3.63 (12H), 4.57 (2H), 6.81 (8H), 6.85 (8H), 7.10 (2H), 7.50 (2H), 7.78 (2H)

[0121]

[0122] Synthesis Example 7 Synthesis of Compound (A-7) A compound represented by the following formula (A-7) was obtained as a pale green solid (yield: 0.09 g, 39%) in the same manner as in Synthesis Example 3, except that the compound represented by formula (2) was changed to the compound represented by formula (3).

[0123] １ H-NMR (400MHz, DMSO-d ６ ): δ (ppm) = 1.17 (3H), 1.35 (1H), 1.88 (1H), 2.32 (1H), 3.65 (12H), 4.57 (2H), 6.81 (8H), 6.85 (8H), 7.09 (2H), 7.49 (2H), 7.77 (2H)

[0124]

[0125] Synthesis Example 8 Synthesis of Compound (A-8) The compound represented by the following formula (A-8) was obtained as a pale green solid (yield: 0.06 g, 28%) in the same manner as in Synthesis Example 4, except that the compound represented by the formula (2) was changed to the compound represented by the formula (3).

[0126] １ H-NMR (400MHz, DMSO-d ６): δ (ppm) = 1.18 (3H), 1.48 (1H), 2.18 (1H), 2.33 (1H), 3.65 (12H), 4.57 (2H), 6.81 (8H), 6.85 (8H), 7.10 (2H), 7.50 (2H), 7.79 (2H)

[0127]

[0128] Synthesis Example 9 Synthesis of Compound (A-23) The compound represented by the following formula (A-23) was obtained as a pale green solid (yield: 0.38 g, 81%) in the same manner as in Synthesis Example 1, except that the compound represented by the above formula (2) was changed to the compound represented by the following formula (4).

[0129] １ H-NMR (400MHz, DMSO-d ６ ): δ (ppm) = 1.16 (3H), 1.76 (1H), 2.22 (1H), 2.47 (1H), 3.73 (12H), 4.57 (2 H), 6.88-6.95 (12H), 7.00 (8H), 7.49 (2H), 7.60 (4H), 7.85 (2H), 7.96 (2H)

[0130]

[0131] Synthesis Example 10 Synthesis of Compound (A-24) The compound represented by the following formula (A-24) was obtained as a milky white solid (yield: 0.16 g, 65%) in the same manner as in Synthesis Example 2, except that the compound represented by the formula (2) was changed to the compound represented by the formula (4).

[0132] １ H-NMR (400MHz, DMSO-d ６ ): δ (ppm) = 1.16 (3H), 1.76 (1H), 2.22 (1H), 2.40 (1H), 3.75 (12H), 4.58 (2 H), 6.88-6.95 (12H), 7.00 (8H), 7.49 (2H), 7.60 (4H), 7.85 (2H), 7.96 (2H)

[0133]

[0134] Synthesis Example 11 Synthesis of Compound (A-25) The compound represented by the following formula (A-25) was obtained as a pale green solid (yield: 0.11 g, 40%) in the same manner as in Synthesis Example 3, except that the compound represented by the formula (2) was changed to the compound represented by the formula (4).

[0135] １ H-NMR (400MHz, DMSO-d ６ ): δ (ppm) = 1.16 (3H), 1.76 (1H), 2.22 (1H), 2.40 (1H), 3.75 (12H), 4.58 (2 H), 6.88-6.95 (12H), 7.00 (8H), 7.49 (2H), 7.60 (4H), 7.85 (2H), 7.96 (2H)

[0136]

[0137] Synthesis Example 12 Synthesis of Compound (A-26) A compound represented by the following formula (A-26) was obtained as a pale green solid (yield: 0.08 g, 31%) in the same manner as in Synthesis Example 4, except that the compound represented by formula (2) was changed to the compound represented by formula (4).

[0138] １ H-NMR (400MHz, DMSO-d ６ ): δ (ppm) = 1.16 (3H), 1.76 (1H), 2.22 (1H), 2.40 (1H), 3.75 (12H), 4.58 (2 H), 6.88-6.95 (12H), 7.00 (8H), 7.49 (2H), 7.60 (4H), 7.85 (2H), 7.96 (2H)

[0139]

[0140] Synthesis Example 13 Synthesis of Compound (A-27) The compound represented by the following formula (A-27) was obtained as a pale green solid (yield: 0.28 g, 72%) in the same manner as in Synthesis Example 1, except that the compound represented by the above formula (2) was changed to the compound represented by the following formula (5).

[0141] １ H-NMR (400MHz, DMSO-d ６): δ (ppm) = 1.18 (3H), 1.79 (1H), 2.23 (1H), 2.46 (1H), 3.65 (12H), 4.57 (2H), 6.84 (8H), 6.89 (8H), 6.95 (2H), 7.20 (2H), 7.25 (2H)

[0142]

[0143] Synthesis Example 14 Synthesis of Compound (A-28) The compound represented by the following formula (A-28) was obtained as a milky white solid (yield: 0.12 g, 58%) in the same manner as in Synthesis Example 2, except that the compound represented by the formula (2) was changed to the compound represented by the formula (5).

[0144] １ H-NMR (400MHz, DMSO-d ６ ): δ (ppm) = 1.18 (3H), 1.79 (1H), 2.23 (1H), 2.40 (1H), 3.63 (12H), 4.57 (2H), 6.84 (8H), 6.89 (8H), 6.95 (2H), 7.20 (2H), 7.25 (2H)

[0145]

[0146] Synthesis Example 15 Synthesis of Compound (A-29) The compound represented by the following formula (A-29) was obtained as a pale green solid (yield: 0.06 g, 26%) in the same manner as in Synthesis Example 3, except that the compound represented by the formula (2) was changed to the compound represented by the formula (5).

[0147] １ H-NMR (400MHz, DMSO-d ６ ): δ (ppm) = 1.17 (3H), 1.35 (1H), 1.88 (1H), 2.32 (1H), 3.65 (12H), 4.57 (2H), 6.84 (8H), 6.89 (8H), 6.95 (2H), 7.20 (2H), 7.25 (2H)

[0148]

[0149] Synthesis Example 16 Synthesis of Compound (A-30) The compound represented by the following formula (A-30) was obtained as a pale green solid (yield: 0.07 g, 32%) in the same manner as in Synthesis Example 4, except that the compound represented by the formula (2) was changed to the compound represented by the formula (5).

[0150] １ H-NMR (400MHz, DMSO-d ６ ): δ (ppm) = 1.18 (3H), 1.48 (1H), 2.18 (1H), 2.33 (1H), 3.65 (12H), 4.57 (2H) 6.84 (8H), 6.89 (8H), 6.95 (2H), 7.20 (2H), 7.25 (2H)

[0151]

[0152] Synthesis Example 17 Synthesis of Compound (A-73) The compound represented by the following formula (A-73) was obtained as a pale green solid (yield: 0.29 g, 79%) in the same manner as in Synthesis Example 1, except that the compound represented by the above formula (2) was changed to the compound represented by the following formula (6).

[0153] １ H-NMR (400MHz, DMSO-d ６ ): δ (ppm) = 1.18 (3H), 1.84 (1H), 2.28 (1H), 2.53 (1H), 3.70 (24H), 4.67 (2H) 6.83 (16H) , 6.89 (16H), 7.12 (4H), 7.40 (4H), 7.73 (6H), 7.75 (2H), 7.94 (2H), 8.10 (6H), 8.79 (2H)

[0154]

[0155] Synthesis Example 18 Synthesis of Compound (A-74) The compound represented by the following formula (A-74) was obtained as a pale green solid (yield: 0.22 g, 56%) in the same manner as in Synthesis Example 3, except that the compound represented by the formula (2) was changed to the compound represented by the formula (6).

[0156] １ H-NMR (400MHz, DMSO-d ６): δ (ppm) = 1.18 (3H), 1.84 (1H), 2.28 (1H), 2.53 (1H), 3.70 (24H), 4.67 (2H) 6.83 (16H) , 6.90 (16H), 7.11 (4H), 7.40 (4H), 7.73 (6H), 7.75 (2H), 7.94 (2H), 8.10 (6H), 8.79 (2H)

[0157]

[0158] Synthesis Example 19 Synthesis of Compound (A-75) The compound represented by the following formula (A-75) was obtained as a pale green solid (yield: 0.21 g, 48%) in the same manner as in Synthesis Example 1, except that the compound represented by the above formula (2) was changed to the compound represented by the following formula (7).

[0159] １ H-NMR (400MHz, DMSO-d ６ ): δ (ppm) = 1.18 (3H), 1.89 (1H), 2.31 (1H), 2.56 (1H), 3.70 (24H), 4.81 (2H) 6.84 ( 16H), 6.90 (16H), 7.12 (4H), 7.42 (4H), 7.62 (2H), 7.74 (8H), 8.17 (6H), 8.31 (2H)

[0160]

[0161] Synthesis Example 20 Synthesis of Compound (A-76) The compound represented by the following formula (A-76) was obtained as a pale green solid (yield: 0.22 g, 60%) in the same manner as in Synthesis Example 3, except that the compound represented by the formula (2) was changed to the compound represented by the formula (7).

[0162] １ H-NMR (400MHz, DMSO-d ６ ): δ (ppm) = 1.19 (3H), 1.89 (1H), 2.30 (1H), 2.53 (1H), 3.73 (24H), 4.81 (2H) 6.82 ( 16H), 6.90 (16H), 7.11 (4H), 7.41 (4H), 7.63 (2H), 7.73 (8H), 8.15 (6H), 8.28 (2H)

[0163]

[0164] [Comparative Compound 1] Synthesis of Compound (B-1) The compound represented by the above formula (A-1) (0.10 g) was subjected to an ion exchange reaction using an ion exchange resin (manufactured by Sigma-Aldrich Co.) to obtain a compound represented by the following formula (B-1) as a green solid (yield: 0.07 g, 71%).

[0165] １ H-NMR (400MHz, DMSO-d ６ ): δ (ppm) = 1.16 (3H), 1.76 (1H), 2.22 (1H), 3.73 (12H), 4.57 (2H), 6.88-6.95 (12H), 7.04 (8H), 7.63 (4H), 7.70 (4H), 8.48 (2H)

[0166]

[0167] Example 1: Fabrication of a photoelectric conversion element and evaluation of photoelectric conversion characteristics. A glass substrate (conductive support 1, manufactured by Solaronix) coated with an etched, fluorine-doped tin oxide (FTO) thin film was ultrasonically cleaned with isopropyl alcohol and then treated with UV ozone. A 15% solution of Tin(IV) oxide in H ２ A tin oxide dispersion liquid containing 0.1% colloidal dispersion (manufactured by Alfa Aesar) and purified water in a volume ratio of 1:3 was applied by spin coating, and then heated at 150°C for 30 minutes using a hot plate to form a tin oxide layer (electron transport layer 2) with a thickness of approximately 40 nm.

[0168] In a glove box under a nitrogen atmosphere, formamidine hydroiodide (1 M, manufactured by Tokyo Chemical Industry Co., Ltd.), lead(II) iodide (1.1 M, manufactured by Tokyo Chemical Industry Co., Ltd.), methylamine hydrobromide (0.2 M, manufactured by Tokyo Chemical Industry Co., Ltd.), and lead(II) bromide (0.2 M, manufactured by Tokyo Chemical Industry Co., Ltd.) were dissolved in a mixed solvent of dimethylformamide and dimethyl sulfoxide in a volume ratio of 4:1. A dimethyl sulfoxide solution of cesium iodide (1.5 M, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the solution so that the cesium content was 5% by composition ratio, to prepare a perovskite precursor solution. In a glove box under a nitrogen atmosphere, the prepared perovskite precursor solution was dripped onto a tin oxide layer, followed by spin coating. 0.3 mL of chlorobenzene was added dropwise during spin coating to form a perovskite precursor film. Then, by heating at 100°C for 1 hour using a hot plate, a Cs(MAFA)Pb(IBr) film with a film thickness of approximately 500 nm was obtained. ３ A layer (photoelectric conversion layer 3) was formed.

[0169] In a glove box under a nitrogen atmosphere, 50 mM of the compound (A-1) which is the hole transport material obtained in Synthesis Example 1 was dissolved in chlorobenzene to prepare a coating solution for the hole transport layer. ３ The hole transport layer coating liquid was spin-coated onto the photoelectric conversion layer 3 to form a hole transport layer 4 having a thickness of about 200 nm.

[0170] On the hole transport layer 4, gold was deposited by vacuum deposition at a vacuum degree of 1×10 －４ A gold electrode (counter electrode 5) was formed at a pressure of about Pa to a thickness of 80 to 100 nm, and a photoelectric conversion element was fabricated.

[0171] A simulated sunlight (AM 1.5, 100 mW / cm) was generated using a white light irradiation device (Otento-Sun SH type, manufactured by Bunkoukeiki Co., Ltd.). ２ ) was irradiated from the conductive support 1 side of the photoelectric conversion element, and the current-voltage characteristics were measured using a source meter (Model 2400 Series Source Meter, manufactured by Keithley Corporation) to obtain the photoelectric conversion efficiency. The obtained current-voltage characteristics and photoelectric conversion efficiency are shown in Table 1.

[0172] Comparative Example 1 A chlorobenzene solution containing 25 mM of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, 0.5 equivalents), which is a dopant additive, and 150 mM of 4-tert-butylpyridine, a basic compound additive, was prepared as a doping solution. A 50 mM chlorobenzene solution was prepared using the prepared doping solution and Spiro-OMeTAD (manufactured by Sigma-Aldrich), a standard hole transport material represented by the following formula (B-2), to form a hole transport layer coating solution. A photoelectric conversion element was fabricated in the same manner as in Example 1, except that the hole transport layer coating solution was used, and the current-voltage characteristics were measured to obtain the photoelectric conversion efficiency. The obtained current-voltage characteristics and photoelectric conversion efficiency are shown in Table 1.

[0173]

[0174] A photoelectric conversion element was prepared in the same manner as in Example 1, except that the compound represented by formula (B-1) having a sulfonic acid group and not forming a salt was used as the hole transport material, and the photoelectric conversion efficiency was obtained by measuring the current-voltage characteristics. The obtained current-voltage characteristics and photoelectric conversion efficiency are shown in Table 1.

[0175]

[0176] From the results in Table 1, it was found that by using a hole transport layer containing the compound of the present invention, a photoelectric conversion element with higher performance can be prepared without using a dopant or a basic additive, as an additive, compared to the case where compound (B-1) containing a dopant and a basic additive is used. This indicates that photoelectric conversion elements containing the compound of the present invention can be prepared by a simple process that reduces production costs by eliminating the addition of additives and does not require an additive operation. It was also found that by using a hole transport layer containing the compound of the present invention, a photoelectric conversion element with higher performance can be prepared compared to the case where compound (B-2), a hole transport material having a sulfonic acid group that does not form a salt, is used. This indicates that a salt-formed hole transport material has superior properties as a photoelectric conversion element compared to a non-salted hole transport material.

[0177] Example 2: Fabrication of a photoelectric conversion element and evaluation of current-voltage characteristics. A flat ITO-coated glass (conductive support 1, manufactured by Geomatec Co., Ltd.) was ultrasonically cleaned with isopropyl alcohol and then treated with UV ozone. Tin(IV) oxide, 15% in H ２ A tin oxide dispersion (electron transport layer coating solution) consisting of tin oxide colloidal dispersion (manufactured by Alfa Aesar) and purified water in a volume ratio of 1:9 was applied by spin coating, followed by heating on a hot plate at 150°C for 30 minutes to form a tin oxide layer (electron transport layer 2) with a thickness of approximately 20 nm.

[0178] In a glove box under a nitrogen atmosphere, formamidine hydroiodide (1 M, manufactured by Tokyo Chemical Industry Co., Ltd.), lead(II) iodide (1.1 M, manufactured by Tokyo Chemical Industry Co., Ltd.), methylamine hydrobromide (0.2 M, manufactured by Tokyo Chemical Industry Co., Ltd.), and lead(II) bromide (0.2 M, manufactured by Tokyo Chemical Industry Co., Ltd.) were dissolved in a mixed solvent of dimethylformamide and dimethyl sulfoxide in a volume ratio of 4:1. A dimethyl sulfoxide solution of cesium iodide (1.5 M, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the solution so that the cesium content was 5% by composition ratio, to prepare a perovskite precursor solution. In a glove box under a nitrogen atmosphere, the prepared perovskite precursor solution was dropped onto a tin oxide layer, followed by spin coating. 0.3 mL of chlorobenzene was added dropwise during spin coating to form a perovskite precursor film. Then, by heating at 100°C for 1 hour using a hot plate, a Cs(MAFA)Pb(IBr) film with a film thickness of approximately 500 nm was obtained. ３ A layer (photoelectric conversion layer 3) was formed.

[0179] In a glove box under a nitrogen atmosphere, the compound (A-5) which is the hole transport material obtained in Synthesis Example 5 was dissolved in chlorobenzene at 50 mM to prepare a hole transport layer coating solution. ３ The hole transport layer coating solution was spin-coated onto the layer (photoelectric conversion layer 3) to form a hole transport layer 4 having a thickness of about 200 nm.

[0180] On the hole transport layer, a vacuum of 1×10 was applied by vacuum deposition.－４ A gold electrode (counter electrode 5) was formed by depositing a gold film of about 80 nm at about Pa, and a photoelectric conversion element was fabricated.

[0181] A simulated sunlight (AM 1.5, 100 mW / cm) was generated using a white light irradiation device (Otento-Sun SH type, manufactured by Bunkoukeiki Co., Ltd.). ２ ) was irradiated onto the photoelectric conversion element from the conductive support side, and the current-voltage characteristics were measured using a source meter (Model 2400 Series Source Meter, manufactured by Keithley Corporation) to obtain the initial photoelectric conversion efficiency.

[0182] After measuring the current-voltage characteristics, the photoelectric conversion element was stored in a desiccator containing silica gel for 28 days, and the current-voltage characteristics were measured again under irradiation with simulated sunlight to obtain the photoelectric conversion efficiency after 28 days. The obtained photoelectric conversion efficiency over time (after 28 days) is shown in Table 2.

[0183] Table 2 shows the rate of change (%) calculated from the obtained initial photoelectric conversion efficiency and the photoelectric conversion efficiency over time, which is the photoelectric conversion efficiency after 28 days, according to the following formula (a-1).

[0184]

[0185] Example 3 A photoelectric conversion element was prepared in the same manner as in Example 2, except that compound (A-7) was dissolved in chlorobenzene to a concentration of 50 mM instead of compound (A-5), and the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days were obtained in the same manner as in Example 2. The obtained photoelectric conversion efficiencies over time (after 28 days) are shown in Table 2. Table 2 also shows the rate of change (%) calculated from the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days using the above formula (a-1).

[0186] Example 4 A photoelectric conversion element was prepared in the same manner as in Example 2, except that compound (A-73) was dissolved in chlorobenzene to a concentration of 50 mM instead of compound (A-5), and the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days were obtained in the same manner as in Example 2. The obtained photoelectric conversion efficiencies over time (after 28 days) are shown in Table 2. Table 2 also shows the rate of change (%) calculated from the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days using the above formula (a-1).

[0187] Example 5 A photoelectric conversion element was prepared in the same manner as in Example 2, except that compound (A-74) was dissolved in chlorobenzene to a concentration of 50 mM instead of compound (A-5), and the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days were obtained in the same manner as in Example 2. The obtained photoelectric conversion efficiencies over time (after 28 days) are shown in Table 2. Table 2 also shows the rate of change (%) calculated from the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days using the above formula (a-1).

[0188] Example 6 A photoelectric conversion element was prepared in the same manner as in Example 2, except that compound (A-27) was dissolved in chlorobenzene at 120°C to a concentration of 30 mM instead of compound (A-5), and the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days were obtained in the same manner as in Example 2. The obtained photoelectric conversion efficiencies over time (after 28 days) are shown in Table 2. Table 2 also shows the rate of change (%) calculated from the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days using the above formula (a-1).

[0189] Example 7 A photoelectric conversion element was prepared in the same manner as in Example 2, except that compound (A-29) was dissolved in chlorobenzene at 120°C to a concentration of 30 mM instead of compound (A-5), and the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days were obtained in the same manner as in Example 2. The obtained photoelectric conversion efficiencies over time (after 28 days) are shown in Table 2. Table 2 also shows the rate of change (%) calculated from the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days using the above formula (a-1).

[0190] Comparative Example 3 In a glove box under a nitrogen stream, 4-tert-butylpyridine and lithium bis(trifluoromethanesulfonyl)imide were dissolved in chlorobenzene as dopants. Spiro-OMeTAD (Sigma-Aldrich), a standard hole transport material represented by formula (B-2) above, was dissolved in the chlorobenzene solution at 50 mM. The solution was adjusted so that the 4-tert-butylpyridine was 3 equivalents and the lithium bis(trifluoromethanesulfonyl)imide was 0.5 equivalents relative to (B-2), forming a hole transport layer coating solution. A photoelectric conversion element was fabricated in the same manner as in Example 2, except for the above. The initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days were measured in the same manner as in Example 2. The photoelectric conversion efficiencies obtained over time (after 28 days) are shown in Tables 2 and 3. Tables 2 and 3 also show the rate of change (%) calculated from the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days according to the above formula (a-1).

[0191]

[0192] The results in Table 2 show that photoelectric conversion elements using compounds (A-5), (A-7), (A-27), (A-29), (A-73), and (A-74) of the present invention as hole transport materials exhibit sufficient photoelectric conversion efficiency and little deterioration in device characteristics, even when the hole transport layer does not contain a dopant, compared to photoelectric conversion elements using compound (B-2), which is a standard hole transport material.

[0193] Example 8 In a glove box under a nitrogen stream, 4-tert-butylpyridine and lithium bis(trifluoromethanesulfonyl)imide were dissolved in chlorobenzene as dopants. Compound (A-5), the hole transport material obtained in Synthesis Example 5, was dissolved in the chlorobenzene solution at 50 mM. The hole transport layer coating solution was prepared so that the 4-tert-butylpyridine was 3 equivalents and the lithium bis(trifluoromethanesulfonyl)imide was 0.5 equivalents relative to (A-5). A photoelectric conversion element was fabricated in the same manner as in Example 2, except for the above. The initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days were measured in the same manner as in Example 2. The photoelectric conversion efficiency over time (after 28 days) obtained are shown in Table 3. The rate of change (%) calculated from the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days using the above formula (a-1) is also shown in Table 3.

[0194] Example 9 A photoelectric conversion element was prepared in the same manner as in Example 8, except that instead of compound (A-5), compound (A-73) was dissolved in a chlorobenzene solution of the dopant to a concentration of 50 mM, and the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days were obtained in the same manner as in Example 8. The photoelectric conversion efficiencies obtained after 28 days (after 28 days) are shown in Table 3. Table 3 also shows the rate of change (%) calculated from the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days using the above formula (a-1).

[0195] Example 10 A photoelectric conversion element was prepared in the same manner as in Example 8, except that instead of compound (A-5), compound (A-74) was dissolved in a chlorobenzene solution of the dopant to a concentration of 50 mM, and the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days were obtained in the same manner as in Example 8. The photoelectric conversion efficiencies obtained after 28 days (after 28 days) are shown in Table 3. Table 3 also shows the rate of change (%) calculated from the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days using the above formula (a-1).

[0196] Example 11 A photoelectric conversion element was prepared in the same manner as in Example 8, except that instead of compound (A-5), compound (A-27) was dissolved in a chlorobenzene solution of the dopant at 60°C to a concentration of 50 mM, and the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days were obtained in the same manner as in Example 8. The obtained photoelectric conversion efficiencies over time (after 28 days) are shown in Table 3. Table 3 also shows the rate of change (%) calculated from the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days using the above formula (a-1).

[0197] Example 12 A photoelectric conversion element was prepared in the same manner as in Example 8, except that instead of compound (A-5), compound (A-29) was dissolved in a chlorobenzene solution of the dopant to a concentration of 50 mM, and the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days were obtained in the same manner as in Example 8. The obtained photoelectric conversion efficiencies over time (after 28 days) are shown in Table 3. Table 3 also shows the rate of change (%) calculated from the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days using the above formula (a-1).

[0198] Example 13 A photoelectric conversion element was prepared in the same manner as in Example 8, except that instead of compound (A-5), compound (A-75) was dissolved in a chlorobenzene solution of the dopant to a concentration of 50 mM, and the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days were obtained in the same manner as in Example 8. The obtained photoelectric conversion efficiencies over time (after 28 days) are shown in Table 3. Table 3 also shows the rate of change (%) calculated from the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days using the above formula (a-1).

[0199] Example 14 A photoelectric conversion element was prepared in the same manner as in Example 8, except that instead of compound (A-5), compound (A-76) was dissolved in a chlorobenzene solution of the dopant to a concentration of 50 mM, and the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days were obtained in the same manner as in Example 8. The obtained photoelectric conversion efficiencies over time (after 28 days) are shown in Table 3. Table 3 also shows the rate of change (%) calculated from the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after 28 days using the above formula (a-1).

[0200]

[0201] The results in Table 3 show that the photoelectric conversion elements using the compounds (A-5), (A-27), (A-29), (A-73), (A-74), (A-75) and (A-76) of the present invention as hole transport materials exhibit sufficient photoelectric conversion efficiency compared to the photoelectric conversion element using the compound (B-2), which is a standard hole transport material, and do not suffer from a decrease in characteristics even when the hole transport layer contains a dopant.

[0202] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Patent Application No. 2021-057864) filed on March 30, 2021, the entirety of which is incorporated by reference. All references cited herein are incorporated in their entirety.

[0203] The compound having a sulfonate group according to the present invention is useful as a photoelectric conversion element having good photoelectric conversion efficiency when used in a hole transport layer, and can provide clean energy as a solar cell that can efficiently convert solar light energy into electrical energy. It can also be applied to other applications such as organic electroluminescence (EL) devices and image sensors.

[0204] REFERENCE SIGNS LIST 1 conductive support 2 electron transport layer 3 photoelectric conversion layer 4 hole transport layer 5 counter electrode

Claims

1. A compound represented by the following general formula (1): 【Chemistry 1】 [In the formula, R １ teeth, a linear or branched alkylene group having 1 to 18 carbon atoms which may have a substituent; a linear or branched alkenylene group having 2 to 20 carbon atoms which may have a substituent, a linear or branched alkynylene group having 2 to 20 carbon atoms which may have a substituent; a cycloalkylene group having 3 to 12 carbon atoms which may have a substituent; a divalent aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent, or a divalent heterocyclic group having 5 to 36 ring atoms which may have a substituent, X represents a monovalent cation other than a hydrogen ion. R ２ ~R ９ are each independently Hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms which may have a substituent; a linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent; a linear or branched alkynyl group having 2 to 20 carbon atoms which may have a substituent; a cycloalkyl group having 3 to 12 carbon atoms which may have a substituent; a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent; a cycloalkoxy group having 3 to 10 carbon atoms which may have a substituent; a linear or branched alkoxycarbonyl group having 1 to 18 carbon atoms which may have a substituent, a thio group having 1 to 18 carbon atoms which may have a substituent; an amino group having 1 to 20 carbon atoms which may have a substituent; an aromatic hydrocarbon group having 6 to 36 carbon atoms which may have a substituent; or an optionally substituted heterocyclic group having 5 to 36 ring atoms. At least one of R 2 to R 9 is a diphenylamino group which may have a substituent, or an aromatic hydrocarbon group having 6 to 36 carbon atoms which is substituted by a diphenylamino group which may have a substituent or a carbazole group.]

2. In the general formula (1), R １ The compound according to claim 1, wherein is a linear or branched alkylene group having 1 to 18 carbon atoms which may have a substituent.

3. 3. The compound according to claim 1, wherein, in the general formula (1), X is an alkali metal ion or an ammonium ion which may have a substituent.

4. 4. The compound according to claim 3, wherein in the general formula (1), the alkali metal ion is at least one selected from the group consisting of a sodium ion, a potassium ion, a rubidium ion and a cesium ion.

5. A hole transport material comprising the compound according to any one of claims 1 to 4.

6. A hole transport material composition for a photoelectric conversion element, comprising the hole transport material according to claim 5 .

7. A photoelectric conversion element using the hole transport material composition for photoelectric conversion according to claim 6.

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