Compound, hole transport material, and photoelectric conversion element using the hole transport material

Abstract

This invention provides a compound useful as a hole transport material for photoelectric conversion elements that can efficiently extract electric current. [Solution] Compound represented by general formula (1): TIFF2026076122000041.tif108170 (In the formula, L 1 ~L 3 (The group is selected from the group represented by formula (2), H, alkyl group, alkoxy group, amino group, thio group, alkylsulfinyl group, alkylsulfonyl group, etc., and at least one of them is the group represented by formula (2).)

Description

[Technical Field]

[0001] The present invention relates to a compound, a hole transport material, and a photoelectric conversion element using the hole transport material. [Background technology]

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

[0003] Perovskite solar cells often use hole transport materials within the device. The main purposes of this are: to improve photoelectric conversion efficiency by enhancing the ability to selectively transport holes, and to protect the perovskite material, which is susceptible to the effects of moisture and oxygen, by bonding the hole transport material with the perovskite photoelectric conversion layer (Non-Patent Literature 3). Spiro-OMeTAD, a spirobifluorene-based organic compound, is widely used as a standard hole transport material. However, there are few reports of hole transport materials that contribute more significantly to photoelectric conversion characteristics than Spiro-OMeTAD. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2017 / 104792 [Non-patent literature]

[0005] [Non-Patent Document 1] J.Am.Chem.Soc., 2009, Vol. 131, pp. 6050–6051 [Non-Patent Document 2] Science, 2012, Vol. 388, pp. 643–647 [Non-Patent Document 3] Chem.Sci., 2019, Vol. 10, pp. 6748–6769 [Overview of the project] [Problems that the invention aims to solve]

[0006] The present invention aims to provide a compound useful as a hole transport material for a photoelectric conversion element that can efficiently extract electric current, a hole transport material containing the compound, and a photoelectric conversion element having excellent photoelectric conversion characteristics and heat resistance using the hole transport material in the hole transport layer. [Means for solving the problem]

[0007] To solve the above problems, the inventors diligently studied ways to improve photoelectric conversion characteristics. As a result, they designed and developed a compound having a specific structure, and found that by using a hole transport layer containing this compound in a photoelectric conversion element, a photoelectric conversion element and a perovskite solar cell with excellent photoelectric conversion characteristics and heat resistance can be obtained. In other words, the gist of the present invention is as follows.

[0008] 1. Compounds represented by the following general formula (1):

[0009] [ka]

[0010] In general formula (1), L 1 ~L 3 Each of them operates independently. The group represented by the following general formula (2), hydrogen atom, halogen atom, hydroxyl group, Linear or branched alkyl groups having 1 to 20 carbon atoms, which may have substituents. A linear or branched alkenyl group having 2 to 20 carbon atoms, which may have substituents. A linear or branched alkoxy group having 1 to 20 carbon atoms, which may have substituents. an aryloxy group having 6 to 30 carbon atoms which may have a substituent an amino group having 0 to 50 carbon atoms which may have a substituent, a thio group having 0 to 20 carbon atoms which may have a substituent, an alkylsulfinyl group having 1 to 20 carbon atoms which may have a substituent, an alkylsulfonyl group having 1 to 20 carbon atoms which may have a substituent, an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have a substituent, or a heterocyclic group having 5 to 30 ring-forming atoms which may have a substituent, L 1 ~L 3 at least one of which is a group represented by the following general formula (2),

[0011]

Chemical formula

[0012] In general formula (2), R 1 ~R 20 are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 20 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 cycloalkyl group having 3 to 10 carbon atoms which may have a substituent, a linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent, an aryloxy group having 6 to 30 carbon atoms which may have a substituent, an amino group having 0 to 20 carbon atoms which may have a substituent, or a thio group having 0 to 20 carbon atoms which may have a substituent, A 1 ~A 3 represents a nitrogen atom or C(R 1a ), and A 1 ~A3 Any two of them are nitrogen atoms, R 1a teeth, hydrogen atom, Linear or branched alkyl groups having 1 to 20 carbon atoms, which may have substituents. A linear or branched alkenyl group having 2 to 20 carbon atoms, which may have substituents. Cycloalkyl groups having 3 to 10 carbon atoms, which may have substituents. A linear or branched alkoxy group having 1 to 20 carbon atoms, which may have substituents. An aryloxy group having 6 to 30 carbon atoms, which may have substituents. An amino group having 0 to 20 carbon atoms, which may have substituents, or A thio group having 0 to 20 carbon atoms, which may have substituents.

[0013] 2. In the above general formula (1), L 1 but, hydrogen atom, An amino group having 0 to 50 carbon atoms, which may have substituents. A thio group having 0 to 20 carbon atoms, which may have substituents. A alkylsulfinyl group having 1 to 20 carbon atoms, which may have substituents. A alkylsulfonyl group having 1 to 20 carbon atoms, which may have substituents. A 6-20 carbon atom aromatic hydrocarbon group which may have substituents, or The compound according to claim 1, wherein the heterocyclic group has 5 to 30 ring-forming atoms, which may have substituents.

[0014] 3. The compound according to 1 or 2, wherein the compound represented by the general formula (1) is the compound represented by the following general formula (3) or general formula (4):

[0015] [ka]

[0016] In general formulas (3) and (4), L 1 , L 2 , A 1 ~A 3 , and R 1 ~R 20 These are defined in the general formulas (1) and (2) above, respectively, except that L in general formula (3) 1 and L 2 This represents a group other than the one represented by the general formula (2), and L in the general formula (4). 1 This represents a group other than the one represented by the general formula (2) above.

[0017] 4. In the above general formula (2), R 1 ~R 20 The compound according to any one of claims 1 to 3, wherein the compound is a linear or branched alkoxy group having 1 to 20 carbon atoms, which may have a hydrogen atom or substituents.

[0018] A hole transport material containing any of the compounds described in 5.1 to 5.4.

[0019] A photoelectric conversion element using the hole transport material described in 6.5. [Effects of the Invention]

[0020] According to the present invention, it is possible to obtain a compound useful as a hole transport material for a photoelectric conversion element that can efficiently extract electric current, a hole transport material containing the compound, and a photoelectric conversion element having excellent photoelectric conversion characteristics and heat resistance by using the hole transport material in the hole transport layer. [Brief explanation of the drawing]

[0021] [Figure 1] This is a schematic cross-sectional view showing the configuration of a photoelectric conversion element according to one embodiment of the present invention. [Modes for carrying out the invention]

[0022] Embodiments of the present invention will be described in detail below. The following descriptions of constituent elements may be based on representative embodiments and specific examples of the present invention, but the present invention is not limited to such embodiments and specific examples. In this specification, numerical ranges represented by "~" mean a range that includes the numbers written before and after "~" as the lower and upper limits. When numerical ranges are described in steps, the upper and lower limits of each numerical range, as well as the numbers described in the examples, can be arbitrarily combined. In this specification, "transparent" and "translucent" mean that the transmittance of light used for photoelectric conversion is 50% or more, for example, 80% or more, 90% or more, or 99% or more. The transmittance of light can be measured using an ultraviolet-visible spectrophotometer.

[0023] <Compound> The compounds according to the present invention, represented by the general formula (1) above, will be described in detail below. In general formula (1), L 1 ~L 3 Each of these independently represents a group represented by the above general formula (2), a hydrogen atom, a halogen atom, a hydroxyl group, a linear or branched alkyl group having 1 to 20 carbon atoms which may be substituted, a linear or branched alkenyl group having 2 to 20 carbon atoms which may be substituted, a linear or branched alkoxy group having 1 to 20 carbon atoms which may be substituted, an aryloxy group having 6 to 30 carbon atoms which may be substituted, an amino group having 0 to 50 carbon atoms which may be substituted, a thio group having 0 to 20 carbon atoms which may be substituted, an alkylsulfinyl group having 1 to 20 carbon atoms which may be substituted, an alkylsulfonyl group having 1 to 20 carbon atoms which may be substituted, an aromatic hydrocarbon group having 6 to 30 carbon atoms which may be substituted, or a heterocyclic group having 5 to 30 ring-forming atoms which may be substituted.

[0024] L 1 ~L 3 Examples of "halogen atoms" represented by this symbol include fluorine, chlorine, bromine, and iodine atoms.

[0025] L 1 ~L 3 In the expression "linear or branched alkyl group having 1 to 20 carbon atoms which may have substituents," specific examples of "linear or branched alkyl group having 1 to 20 carbon atoms" include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-pentyl group, isopentyl group, n-hexyl group, 2-ethylhexyl group, heptyl group, octyl group, isooctyl group, nonyl group, and decyl group.

[0026] L 1 ~L 3 In the expression "linear or branched alkenyl groups having 2 to 20 carbon atoms that may have substituents," examples of "linear or branched alkenyl groups having 2 to 20 carbon atoms" include ethenyl group (vinyl group), 1-propenyl group, 2-propenyl group (allyl group), 1-methylethenyl group, 1-butenyl group, 2-butenyl group, 1-pentenyl group, 1-hexenyl group, 2-methyl-1-propenyl group, 2-methyl-2-propenyl group, 1-ethylethenyl group, and linear or branched alkenyl groups having 2 to 20 carbon atoms formed by the bonding of multiple of these alkenyl groups.

[0027] L 1 ~L 3 In the expression "linear or branched alkoxy group having 1 to 20 carbon atoms which may have substituents," examples of "linear or branched alkoxy group having 1 to 20 carbon atoms" include methoxy group, ethoxy group, propoxy group, n-butoxy group, n-pentyloxy group, n-hexyloxy group, heptyloxy group, octyloxy group, nonyloxy group, decyloxy group, isopropoxy group, isobutoxy group, s-butoxy group, t-butoxy group, isooctyloxy group, and t-octyloxy group.

[0028] L 1 ~L 3In the expression "aryloxy group having 6 to 30 carbon atoms which may have substituents," specific examples of "aryloxy group having 6 to 30 carbon atoms" include phenoxy group, tolyloxy group, biphenylyloxy group, terphenylyloxy group, naphthyloxy group, anthryloxy group, phenanthryloxy group, fluorenyloxy group, and indenyloxy group.

[0029] L 1 ~L 3 In the expression "amino groups having 0 to 50 carbon atoms that may have substituents," the "amino groups having 0 to 50 carbon atoms" specifically include unsubstituted amino groups (-NH2), monosubstituted amino groups such as ethylamino group, acetylamino group, and phenylamino group, and disubstituted amino groups such as diethylamino group, diphenylamino group, and acetylphenylamino group. Note that the "substituted" group in "unsubstituted amino group," "monosubstituted amino group," and "disubstituted amino group" refers to a substituent different from the "substituted" in "amino groups having 0 to 50 carbon atoms that may have substituents." That is, if "amino groups having 0 to 50 carbon atoms that may have substituents" is a "monosubstituted amino group that may have substituents," it means that the hydrogen atoms of the monosubstituted amino group or the "substituted" group may further have the "substituted" described below. The same applies to the following explanation of thio groups, etc. The "amino group having 0 to 50 carbon atoms which may have substituents" is preferably an unsubstituted amino group (-NH2), an unsubstituted monosubstituted amino group, or an unsubstituted disubstituted amino group.

[0030] L 1 ~L 3 In the expression "thio groups having 0 to 20 carbon atoms that may have substituents," examples of "thio groups having 0 to 20 carbon atoms" include unsubstituted thio groups (thiol groups: -SH), methyl thio groups, ethyl thio groups, propyl thio groups, phenyl thio groups, and biphenyl thio groups.

[0031] L1 ~L 3 In the expression "alkyl sulfinyl groups having 1 to 20 carbon atoms that may have substituents," specific examples of "alkyl sulfinyl groups having 1 to 20 carbon atoms" include methyl sulfinyl group (-S=O-Me), ethyl sulfinyl group, propyl sulfinyl group, butyl sulfinyl group, pentyl sulfinyl group, and hexyl sulfinyl group.

[0032] L 1 ~L 3 In the expression "alkylsulfonyl groups having 1 to 20 carbon atoms that may have substituents," examples of "alkylsulfonyl groups having 1 to 20 carbon atoms" include methylsulfonyl group (-S(=O)2-Me), ethylsulfonyl group, propylsulfonyl group, butylsulfonyl group, pentylsulfonyl group, and hexylsulfonyl group.

[0033] L 1 ~L 3 In the "aromatic hydrocarbon group having 6 to 30 carbon atoms that may have substituents" represented by , specific examples of "aromatic hydrocarbon group having 6 to 30 carbon atoms" include phenyl group, biphenyl group, terphenyl group, naphthyl group, anthracenyl group (anthryl group), phenanthryl group, fluorenyl group, indenyl group, pyrenyl group, perilenyl group, fluoranthenyl group, triphenylenyl group, and the like. In this invention, "aromatic hydrocarbon group" includes "condensed polycyclic aromatic group".

[0034] L 1 ~L 3In the expression "heterocyclic groups having 5 to 30 ring-forming atoms which may have substituents," specific examples of "heterocyclic groups having 5 to 30 ring-forming atoms" include pyridyl groups, pyrimidinyl groups, triazinyl groups, thienyl groups, furyl groups (furanyl groups), pyrrolyl groups, imidazolyl groups, pyrazolyl groups, triazolyl groups, quinolyl groups, isoquinolyl groups, naphthilidinyl groups, acridinyl groups, phenanthrolinyl groups, benzofuranyl groups, benzothienyl groups, oxazolyl groups, indolyl groups, carbazolyl groups, benzoxazolyl groups, thiazolyl groups, benzothiazolyl groups, quinoxalinyl groups, benzimidazolyl groups, dibenzofuranyl groups, dibenzothienyl groups, and carbonyl groups.

[0035] L 1 ~L 3In the following expressions, "a linear or branched alkyl group having 1 to 20 carbon atoms which may have substituents," "a linear or branched alkenyl group having 2 to 20 carbon atoms which may have substituents," "a linear or branched alkoxy group having 1 to 20 carbon atoms which may have substituents," "an aryloxy group having 6 to 30 carbon atoms which may have substituents," "an amino group having 0 to 50 carbon atoms which may have substituents," "a thio group having 0 to 20 carbon atoms which may have substituents," "an alkylsulfinyl group having 1 to 20 carbon atoms which may have substituents," "an alkylsulfonyl group having 1 to 20 carbon atoms which may have substituents," "an aromatic hydrocarbon group having 6 to 30 carbon atoms which may have substituents," or "a heterocyclic group having 5 to 30 ring-forming atoms which may have substituents," the "substituents" specifically include halogen atoms such as fluorine, chlorine, bromine, and iodine; cyano groups; hydroxyl groups; nitro groups; nitroso groups; carboxyl groups; phosphate groups; thioxo groups (>C=S); trimethylsilyl groups; and methyl groups. Ester groups and carboxylic acid ester groups such as ethyl ester groups; linear or branched alkyl groups having 1 to 18 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-pentyl group, isopentyl group, n-hexyl group, 2-ethylhexyl group, heptyl group, octyl group, isooctyl group, nonyl group, and decyl group; ethenyl group (vinyl group), 1-propenyl group, 2-propenyl group (allyl group), 1-butenyl group, 2-butenyl group Linear or branched alkenyl groups having 2 to 18 carbon atoms, such as 1-pentenyl, 1-hexenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, and 1-ethylethenyl; 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 phenyl, naphthyl, anthryl, phenanthryl, and pyrenyl;Pyridyl group, pyrimidinyl group, triazinyl group, thienyl group, furyl group (furanyl group), pyrrolyl group, imidazolyl group, pyrazolyl group, triazolyl group, quinolyl group, isoquinolyl group, naphthilidinyl group, acridinyl group, phenanthrolinyl group, benzofuranyl group, benzothienyl group, oxazolyl group, indolyl group, carbazolyl group, benzoxazolyl group, thiazolyl group, benzothiazolyl group, quinoxalinyl group, benzimidazolyl group, dibenzofuranyl group, dibenzothienyl group, and carbonyl Examples include heterocyclic groups with 5 to 20 ring-forming atoms, such as 1-NH groups; monosubstituted amino groups such as unsubstituted amino groups (-NH2), ethylamino groups, acetylamino groups, and phenylamino groups, or disubstituted amino groups such as diethylamino groups, diphenylamino groups, and acetylphenylamino groups, with 0 to 18 carbon atoms; and thio groups such as unsubstituted thio groups (thiol groups: -SH), methylthio groups, ethylthio groups, propylthio groups, phenylthio groups, and biphenylthio groups, with 0 to 18 carbon atoms. These "substituents" may be present one at a time or multiple times, and if multiple substituents are present, they may be identical or different from one another. Furthermore, these "substituents" may also have the substituents exemplified above.

[0036] In general formula (1), L 1 ~L 3This includes a group represented by general formula (2), a hydrogen atom, a halogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may be substituted, a linear or branched alkoxy group having 1 to 20 carbon atoms which may be substituted, an amino group having 0 to 50 carbon atoms which may be substituted, a thio group having 0 to 20 carbon atoms which may be substituted, an alkylsulfinyl group having 1 to 20 carbon atoms which may be substituted, an alkylsulfonyl group having 1 to 20 carbon atoms which may be substituted, and an aromatic hydrocarbon having 6 to 30 carbon atoms which may be substituted. It is preferably a group or a heterocyclic group having 5 to 30 ring-forming atoms, which may have substituents, and more preferably a group represented by general formula (2), a hydrogen atom, an amino group having 0 to 50 carbon atoms, which may have substituents, a thio group having 0 to 20 carbon atoms, which may have substituents, an alkylsulfinyl group having 1 to 20 carbon atoms, which may have substituents, an alkylsulfonyl group having 1 to 20 carbon atoms, which may have substituents, an aromatic hydrocarbon group having 6 to 20 carbon atoms, which may have substituents, or a heterocyclic group having 5 to 30 ring-forming atoms, which may have substituents.

[0037] In general formula (1), L 1 ~L 3 At least one of them is a group represented by the general formula (2) above. 1 If L is a group other than the one represented by general formula (2), 1Preferably, the group consists of a hydrogen atom, a halogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms (which may be substituted), a linear or branched alkoxy group having 1 to 20 carbon atoms (which may be substituted), an amino group having 0 to 50 carbon atoms (which may be substituted), a thio group having 0 to 20 carbon atoms (which may be substituted), an alkylsulfinyl group having 1 to 20 carbon atoms (which may be substituted), an alkylsulfonyl group having 1 to 20 carbon atoms (which may be substituted), an aromatic hydrocarbon group having 6 to 30 carbon atoms (which may be substituted), or a heterocyclic group having 5 to 30 ring-forming atoms (which may be substituted). More preferably, the group is a hydrogen atom, an amino group having 0 to 50 carbon atoms which may have substituents, a thio group having 0 to 20 carbon atoms which may have substituents, an alkylsulfinyl group having 1 to 20 carbon atoms which may have substituents, an alkylsulfonyl group having 1 to 20 carbon atoms which may have substituents, an aromatic hydrocarbon group having 6 to 20 carbon atoms which may have substituents, or a heterocyclic group having 5 to 30 ring-forming atoms which may have substituents, and even more preferably, the group is a hydrogen atom, an amino group having 0 to 50 carbon atoms which may have substituents, or an aromatic hydrocarbon group having 6 to 20 carbon atoms which may have substituents.

[0038] In general formula (1), A 1 ~A 3 is a nitrogen atom or C(R 1a ) represents. Note that A 1 ~A 3 Any two of them are nitrogen atoms, and the remaining A 1 ~A 3 is C(R 1a ) is the case here, R 1aThis represents a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may be substituted, a linear or branched alkenyl group having 2 to 20 carbon atoms which may be substituted, a cycloalkyl group having 3 to 10 carbon atoms which may be substituted, a linear or branched alkoxy group having 1 to 20 carbon atoms which may be substituted, an aryloxy group having 6 to 30 carbon atoms which may be substituted, an amino group having 0 to 20 carbon atoms which may be substituted, or a thio group having 0 to 20 carbon atoms which may be substituted.

[0039] In the above general formula (2), R 1 ~R 20 Each of these independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 20 carbon atoms which may be substituted, a linear or branched alkenyl group having 2 to 20 carbon atoms which may be substituted, a cycloalkyl group having 3 to 10 carbon atoms which may be substituted, a linear or branched alkoxy group having 1 to 20 carbon atoms which may be substituted, an aryloxy group having 6 to 30 carbon atoms which may be substituted, an amino group having 0 to 20 carbon atoms which may be substituted, or a thio group having 0 to 20 carbon atoms which may be substituted.

[0040] The aforementioned R 1a And in general formula (2), R 1 ~R 20 In the "linear or branched alkyl group having 1 to 20 carbon atoms which may have substituents" and "linear or branched alkenyl group having 2 to 20 carbon atoms which may have substituents" represented by the above L 1 ~L 3 The same examples as those given for "linear or branched alkyl groups having 1 to 20 carbon atoms that may have substituents" and "linear or branched alkenyl groups having 2 to 20 carbon atoms that may have substituents" can be cited.

[0041] The aforementioned R 1a And in general formula (2), R 1 ~R 20 In the expression "a cycloalkyl group having 3 to 10 carbon atoms which may have substituents," specific examples of "a cycloalkyl group having 3 to 10 carbon atoms" include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclodecyl group, and cyclododecyl group.

[0042] The aforementioned R 1a And in general formula (2), R 1 ~R 20 In the "alkoxy group having 1 to 20 carbon atoms that may have substituents" and the "aryloxy group having 6 to 30 carbon atoms that may have substituents" represented by the above, the "alkoxy group having 1 to 20 carbon atoms" and the "aryloxy group having 6 to 30 carbon atoms" are specifically the L 1 ~L 3 The same examples as those given for "alkoxy groups having 1 to 20 carbon atoms that may have substituents" and "aryloxy groups having 6 to 30 carbon atoms that may have substituents" can be cited.

[0043] The aforementioned R 1a And in general formula (2), R 1 ~R 20 In the "amino group having 0 to 20 carbon atoms that may have substituents" represented by the above, the "amino group having 0 to 20 carbon atoms" specifically refers to the L 1 ~L 3 Among the examples of "amino groups having 0 to 50 carbon atoms that may have substituents," as represented by [the formula], we can cite "amino groups having 0 to 20 carbon atoms."

[0044] The aforementioned R 1a And in general formula (2), R 1 ~R 20In the "thio group having 0 to 20 carbon atoms which may have a substituent" represented by , the "thio group having 0 to 20 carbon atoms" specifically includes the above-mentioned L 1 ~L 3 Examples thereof can be the same as those exemplified for the "thio group having 0 to 20 carbon atoms which may have a substituent" represented by .

[0045] The above-mentioned R 1a and in general formula (2), R 1 ~R 20 In the "linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent", "linear or branched alkenyl group having 2 to 20 carbon atoms which may have a substituent", "cycloalkyl group having 3 to 10 carbon atoms which may have a substituent", "linear or branched alkoxy group having 1 to 20 carbon atoms which may have a substituent", "aryloxy group having 6 to 30 carbon atoms which may have a substituent", "amino group having 0 to 20 carbon atoms which may have a substituent", or "thio group having 0 to 20 carbon atoms which may have a substituent", the "substituent" can be the same as those exemplified as the "substituent" in the "linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent" etc. represented by the above-mentioned L 1 ~L 3 Examples thereof can be the same as those exemplified as the "substituent" in the "linear or branched alkyl group having 1 to 20 carbon atoms which may have a substituent" etc. represented by the above-mentioned L

[0046] In general formula (2), R 5 and R 6 and R 15 and R 16 may be bonded to each other by a single bond or via an oxygen atom, sulfur atom, selenium atom, or nitrogen atom to form a ring.

[0047] <{ In general formula (1), R 1a is preferably a hydrogen atom or a substituted or unsubstituted phenyl group, more preferably a hydrogen atom. In general formula (2), R 1 ~R 20R is preferably a hydrogen atom, an amino group having 0 to 20 carbon atoms which may have substituents, or a linear or branched alkoxy group having 1 to 20 carbon atoms which may have substituents, and more preferably a hydrogen atom or a linear or branched alkoxy group having 1 to 20 carbon atoms which may have substituents. 3 , R 8 , R 13 , and R 18 However, each of these is a linear or branched alkoxy group having 1 to 20 carbon atoms, which may each have substituents, and R 1 , R 2 , R 4 , R 5 , R 6 , R 7 , R 9 , R 10 , R 11 , R 12 , R 14 , R 15 , R 16 , R 17 , R 19 , and R 20 It is even more preferable that all of them are hydrogen atoms.

[0048] As described above, in general formula (1), L 1 ~L 3 At least one of them represents a group represented by the general formula (2) above, L 1 L is a group other than the group represented by general formula (2). 2 and L 3 It is preferable that one or both of the groups are represented by the general formula (2) above. That is, it is preferable that the compound represented by the general formula (1) above is a compound represented by the general formula (3) or (4) above. Note that in general formulas (3) and (4), L 1 , L 2 , A 1 ~A 3 , and R 1 ~R 20 These are defined as in the general formulas (1) and (2) above, respectively. However, L in general formula (3) 1 and L 2This represents groups other than those represented by general formula (2), and L in general formula (4). 1 This represents a group other than those represented by general formula (2).

[0049] Furthermore, in general formula (2), the diarylamino group is preferably substituted at the 3rd and 6th positions of the carbazole. That is, the compound represented by general formula (3) or (4) is preferably the compound represented by general formula (5) or (6) below, respectively. Note that in general formulas (5) and (6), L 1 , L 2 , A 1 ~A 3 , and R 1 ~R 20 These are defined as in the general formulas (1) and (2) above, respectively. However, L in general formula (5) 1 and L 2 This represents groups other than those represented by general formula (2), and L in general formula (6). 1 This represents a group other than those represented by general formula (2).

[0050] [ka]

[0051] In general formulas (1), (3), (4), (5), and (6), A 1 ~A 3 Any two of these represent nitrogen atoms. Here, A 1 and A 2 A may be a nitrogen atom, 2 and A 3 A may be a nitrogen atom, and A 1 and A 3 It may be a nitrogen atom.

[0052] Specific examples of compounds according to the present invention represented by the general formula (1) are shown below, but the present invention is not limited to these. In the following example compounds, hydrogen atoms, carbon atoms, etc., are partially omitted. Furthermore, the following example compounds are just examples of possible isomers, and the compounds according to the present invention encompass all other isomers. Moreover, the compounds according to the present invention may be a mixture of two or more isomers.

[0053] [ka]

[0054] [ka]

[0055] [ka]

[0056] [ka]

[0057] [ka]

[0058] [ka]

[0059] [ka]

[0060] [ka]

[0061] [ka]

[0062] [ka]

[0063] [ka]

[0064] [ka]

[0065] [ka]

[0066] [ka]

[0067] [ka]

[0068] The compound according to the present invention, represented by the general formula (1), can be synthesized by known methods. For example, the compound represented by the general formula (1) can be obtained by a nucleophilic substitution reaction between a dichloropyrimidine derivative and a 3,6-triarylaminosubstituted carbazole represented by the general formula (7) below. Note that in the general formula (7) below, R 1 ~R 20 This is as defined in the general formula (2) above.

[0069] [ka]

[0070] Methods for purifying compounds represented by general formula (1) include purification by column chromatography, adsorption purification using silica gel, activated carbon, or activated clay, and recrystallization or crystallization using solvents. Furthermore, combining these methods can yield compounds of even higher purity. These compounds can be identified by nuclear magnetic resonance analysis (NMR).

[0071] <Hole transport materials> Compounds represented by general formula (1) can be used as hole transport materials. That is, the hole transport material according to the present invention includes a compound represented by general formula (1). Specifically, compounds represented by general formula (1) can be suitably used as hole transport materials in photoelectric conversion elements and in the field of organic electronics. Preferred embodiments of the photoelectric conversion element according to the present invention will be described below.

[0072] <Photoelectric conversion element> The photoelectric conversion element according to the present invention is a photoelectric conversion element that uses a hole transport material containing the compound of the present invention represented by general formula (1) as the hole transport layer. The photoelectric conversion element according to the present invention will be described below with reference to the drawings.

[0073] Figure 1 is a schematic cross-sectional view showing the configuration of a photoelectric conversion element according to one embodiment of the present invention. As shown in Figure 1, the photoelectric conversion element 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. However, the configuration of the photoelectric conversion element is not limited to the configuration shown in Figure 1. Furthermore, a solar cell is preferred as the photoelectric conversion element of the present invention, and a perovskite solar cell (perovskite-type photoelectric conversion element) is particularly preferred, but is not limited thereto. A 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. A perovskite-type photoelectric conversion element may also be configured in the order of a conductive support, a hole transport layer, a photoelectric conversion layer (perovskite layer), an electron transport layer, and a counter electrode.

[0074] (Conductive support) The conductive support 1 needs to be translucent, allowing light that contributes to photoelectric conversion to pass through. Furthermore, since the conductive support is a component that has the function of extracting current from the photoelectric conversion layer, it is preferable that it be a conductive substrate. Examples of conductive materials constituting the conductive substrate include conductive transparent oxide semiconductors such as 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 (In2O3), and indium-tin composite oxide. Among these, it is preferable to use tin-doped indium oxide (ITO) or fluorine-doped tin oxide (FTO).

[0075] The substrate is not particularly limited, and glass substrates, plastic substrates, metal substrates, etc., can be used. The substrate may be transparent or opaque. Examples of substrates include plastic substrates such as polyethylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose acetate propionate, cellulose acetate phthalate, cellulose nitrate, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyetherketone, polyimide, polyethersulfone, polyphenylene sulfide, polysulfones, polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethyl methacrylate, acrylic or polyarylates, and organic-inorganic hybrid resins; inorganic substrates such as glass, quartz, aluminum oxide, silicon, silicon oxide, tantalum dioxide, tantalum pentoxide, and indium tin oxide; and metal substrates such as gold, copper, chromium, titanium, and aluminum.

[0076] (electron transport layer) The electron transport layer 2 is a layer located between the conductive support 1 and the photoelectric conversion layer (perovskite layer) 3. It is preferable, but not limited to, that the electron transport layer 2 be formed on the conductive support 1. The electron transport layer has the function of improving the efficiency of electron transfer from the photoelectric conversion layer to the electrode and blocking the movement of holes.

[0077] Specific examples of semiconductors that form electron transport layers include metal oxides such as tin oxide (SnO, SnO2, SnO3, etc.), titanium oxide (TiO2, etc.), tungsten oxide (WO2, WO3, W2O3, etc.), zinc oxide (ZnO), niobium oxide (Nb2O5, etc.), tantalum oxide (Ta2O5, etc.), yttrium oxide (Y2O3, etc.), and strontium titanate (SrTiO3, etc.); metal sulfides 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. These semiconductors may be used individually or in combination of two or more. In the present invention, it is preferable to use one or more materials selected from tin oxide, titanium oxide, and zinc oxide as the semiconductor.

[0078] A paste containing commercially available semiconductor nanoparticles may be used to form the electron transport layer, or a paste (coating solution for electron transport layer) prepared by dispersing commercially available semiconductor fine powder in a solvent may be used. Specific examples of solvents used when 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-based solvents such as n-hexane, cyclohexane, benzene, and toluene. These solvents may be used individually or as a mixture of two or more solvents.

[0079] Methods for dispersing semiconductor fine powder in a solvent include grinding the powder in a mortar and then dispersing it, or using a disperser such as a ball mill, paint conditioner, vertical bead mill, horizontal bead mill, or attritor. When preparing the paste, it is preferable to add a surfactant or the like to prevent aggregation of semiconductor fine particles. It is also preferable to add a thickener such as polyethylene glycol to increase the viscosity of the paste.

[0080] The electron transport layer can be formed using known film-forming methods depending on the material constituting the electron transport layer. Any coating method using a coating solution can be used to form the electron transport layer. Examples of coating methods include, but are not limited to, wet coating methods such as spin coating, inkjet, doctor blade, drop casting, squeegee, screen printing, reverse roll coating, gravure coating, kiss coating, roll brushing, spray coating, air knife coating, wire barber coating, pipe doctor, impregnation coating, and curtain coating, in which the coating solution is applied to a conductive substrate and then the solvent and additives are removed by firing (heating) to form the film, as well as sputtering, vapor deposition, electrodeposition, and microwave irradiation. In the present invention, it is preferable to form the film by spin coating using a coating solution for the electron transport layer prepared by the above method. The conditions for spin coating can be set as appropriate. The atmosphere in which the film is formed is not particularly limited and may be air.

[0081] From the viewpoint of further improving photoelectric conversion efficiency, the thickness of the electron transport layer is usually preferably 5 nm to 100 nm, and more preferably 10 nm to 50 nm, when a dense electron transport layer is used. In the present invention, when a porous (mesoporous) metal oxide is used in addition to the dense electron transport layer, the thickness of the electron transport layer is usually preferably 20 to 200 nm, and more preferably 50 to 150 nm.

[0082] (Photoelectric conversion layer) In the photoelectric conversion element according to the present invention, it is preferable that a photoelectric conversion layer (perovskite layer) 3 is formed on the electron transport layer 2. When the photoelectric conversion element of the present invention is used as a perovskite-type photoelectric conversion element, the perovskite material used for the photoelectric conversion layer can be a material having a structure represented by the general formula ABX3. Here, A, B, and X represent, respectively, A: organic cation or monovalent metal cation; B: metal cation; and X: halide anion. Specifically, A: K + , Rb + , Cs + CH3NH3 + (Hereafter, "MA: Methylammonium"), NH=CHNH2 + (Hereinafter, "FA: Formamidinium"), and CH3CH2NH3 + (Hereafter, "EA: Ethylammonium"); B: Pb and Sn; and X: I - and Br - Examples include, but are not limited to, perovskite materials represented by any composition such as MAPbI3, FAPbI3, EAPbI3, CsPbI3, MASnI3, FASnI3, EASnI3, MAPbBr3, FAPbBr3, EAPbBr3, MASnBr3, FASnBr3, and EASnBr3, and perovskite materials composed of mixed cations or mixed anions represented by any composition such as (FAMA)Pb(IBr)3, K(FAMA)Pb(IBr)3, Rb(FAMA)Pb(IBr)3, and Cs(FAMA)Pb(IBr)3. These perovskite materials may be used individually or in combination of two or more. The photoelectric conversion layer may also contain light absorbers other than perovskite materials.

[0083] Any coating method using a coating solution can be used to form the photoelectric conversion layer (perovskite layer). Specifically, the same method as the electron transport layer can be used. However, in forming the photoelectric conversion layer, a perovskite precursor solution prepared by dissolving a perovskite precursor in a solvent is used as the coating solution.

[0084] The perovskite precursor may be a commercially available material. In the present invention, it is preferable, but not limited to, to use a precursor consisting of lead halide, methylammonium halide, formamidine halide, and cesium halide in any composition.

[0085] From the viewpoint of solubility of the precursor, suitable solvents for dissolving the perovskite precursor include, but are not limited to, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and γ-butyrolactone. The solvent may be used alone or as a mixture of two or more solvents. Preferably, a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide is used. Furthermore, it is preferable to use a solvent with a low water content of 10 ppm or less, achieved by dehydration using molecular sieves or the like.

[0086] The atmosphere in which the photoelectric conversion layer (perovskite layer) is deposited is preferably a dry atmosphere, and more preferably a dry inert gas atmosphere such as a glove box, from the viewpoint of preventing moisture contamination and producing highly efficient perovskite solar cells with good reproducibility.

[0087] The heating temperature for forming the photoelectric conversion layer (perovskite layer) is preferably 50 to 200°C, and more preferably 70 to 150°C, from the viewpoint of generating perovskite material from the precursor. The heating time is preferably 10 to 90 minutes, and more preferably 10 to 60 minutes. Heating can be carried out, for example, using a hot plate.

[0088] The thickness of the photoelectric conversion layer (perovskite layer) is preferably 50 to 1000 nm, and more preferably 300 to 700 nm, from the viewpoint of further suppressing performance degradation due to defects and delamination, and from the viewpoint of the photoelectric conversion layer having a sufficient light absorption rate and suppressing excessively high resistance of the device.

[0089] To improve the efficiency of charge transfer between layers, a passivation process may be performed by covering surface defects in the photoelectric conversion layer (perovskite layer). Passivation can be carried out by any coating method that covers surface defects using a coating solution, and the same coating method as the electron transport layer deposition method can be used.

[0090] For passivation, it is preferable to use a compound having a quaternary ammonium salt structure, but it is not limited to this, and multiple compounds may be used in combination. Specifically, examples include phenylethylammonium bromide, n-hexylammonium bromide, and n-hexyltrimethylammonium bromide.

[0091] The passivation process is preferably carried out under a dry atmosphere. A vacuum method is preferred for removing the solvent from the coating solution. The coating thickness is not particularly limited as long as it effectively enhances the efficiency of charge transfer, but it is preferably 10 nm or less, and more preferably 5 nm or less.

[0092] (Hole transport layer) The hole transport layer 4 is a layer that has the function of transporting holes and is located between the photoelectric conversion layer (perovskite layer) 3 and the counter electrode 5. The hole transport layer has the function of improving the efficiency of hole movement from the photoelectric conversion layer to the electrode and blocking electron movement. For example, the hole transport layer can be made of a conductor, semiconductor, or organic hole transport material. Additives may be included in the hole transport layer for the purpose of further improving the hole transport properties.

[0093] In the photoelectric conversion element according to the present invention, the hole transport layer contains a compound represented by the general formula (1) as a hole transport material. One or more compounds represented by the general formula (1) can be used in the hole transport layer, and the compound represented by the general formula (1) can also be used in combination with other hole transport materials not belonging to the present invention.

[0094] Other specific examples of hole transport materials not covered by the present invention include compound semiconductors containing monovalent copper such as CuI, CuInSe2, and CuS; and compounds containing metals other than copper such as GaP, NiO, CoO, FeO, Bi2O3, MoO2, and Cr2O3. These oxide metals may be used mixed in the hole transport layer or laminated on top of the hole transport material. Other organic hole transport materials include, for example, 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.

[0095] Any coating method using a coating solution can be used to form the hole transport layer. Specifically, the same method as the electron transport layer formation method can be used. However, in the formation of the hole transport layer, a coating solution for the hole transport layer is used as the coating solution.

[0096] The solvents used in the coating solution for the hole transport layer include aromatic organic solvents such as benzene, toluene, xylene, mesitylene, tetralin (1,2,3,4-tetrahydronaphthalene), monochlorobenzene (chlorobenzene), o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, and nitrobenzene; alkyl halogenated organic solvents such as dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2-trichloroethane, and dichloromethane; nitrile solvents such as benzonitrile and acetonitrile; and tetrahydrofuran, dioxane, and diisopropyl alcohol. Examples of suitable solvents include, but are not limited to, ether-based solvents such as pyru ether, c-pentyl methyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and propylene glycol monomethyl ether; ester-based solvents such as ethyl acetate and propylene glycol monomethyl ether acetate; and alcohol-based solvents such as methanol, isopropanol, n-butanol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, cyclohexanol, and 2-n-butoxyethanol. The solvent may be used alone or as a mixture of two or more solvents. The solvent to be used can be appropriately selected depending on the structure of the material. Among these, it is preferable to use a solvent selected from aromatic organic solvents and alkyl halogenated organic solvents. It is also preferable to use a dehydrated solvent with a water content of 10 ppm or less.

[0097] From the viewpoint of further improving the photoelectric conversion efficiency, the thickness of the hole transport layer is preferably 5 to 500 nm, and more preferably 10 to 250 nm.

[0098] From the viewpoint of preventing moisture contamination and enabling the reproducible production of highly efficient perovskite solar cells, a dry atmosphere is preferred for forming the hole transport layer.

[0099] The hole transport layer may contain dopants (or oxidizing agents) or basic compounds (or basic additives) as additives. Incorporating additives into the hole transport layer to improve the carrier concentration of the hole transport material in the hole transport layer (doping) leads to an improvement in the photoelectric conversion efficiency of the photoelectric conversion element. When dopants and basic additives are included in the hole transport layer, the total amount of these additives is preferably 7.0 equivalents or less, and more preferably 4.0 equivalents or less, per equivalent of the hole transport material.

[0100] Specific examples of dopants include bis(trifluoromethanesulfonyl)imide lithium (LiTFSI), bis(trifluoromethanesulfonyl)imide silver, bis(trifluoromethanesulfonyl)imide zinc (II), bis(trifluoromethanesulfonyl)imide copper (II), bis(trifluoromethanesulfonyl)imide magnesium (II), bis(trifluoromethanesulfonyl)imide calcium (II), tris(2-(1H-pyrazole-1-yl)-4-tert-butylpyridine)cobalt(III)tri[bis(trifluoromethane)sulfonimide](FK209), NOSbF6, SbCl5, and SbF5. Among these, bis(trifluoromethanesulfonyl)imide lithium (LiTFSI) is preferred, but the dopants are not limited to this.

[0101] The amount of dopant used is preferably 2.0 equivalents or less, and more preferably 0.5 equivalents or less, relative to 1 equivalent of hole transport material contained in the hole transport layer.

[0102] Specific examples of basic compounds (basic additives) include 4-tert-butylpyridine (tBP), 2-picoline, and 2,6-lutidine. Basic compounds are often used in combination with dopants. In the present invention, it is also desirable to use basic compounds in combination with dopants, and it is particularly preferable to use 4-tert-butylpyridine.

[0103] The amount of basic compound used is preferably 5.0 equivalents or less, and more preferably 3.5 equivalents or less, relative to 1 equivalent of hole transport material contained in the hole transport layer.

[0104] While including additives in the hole transport layer can improve the photoelectric conversion efficiency of a photoelectric conversion element, there are concerns that using dopants, which are additives, can reduce the durability of photoelectric conversion elements using organic compounds, thereby shortening the overall lifespan of the element (Non-Patent Literature 3). For this reason, there is a need for the development of photoelectric conversion elements having a hole transport layer with reduced dopant content. Furthermore, reducing the dopant content can lead to a reduction in additive costs and manufacturing process costs. In the photoelectric conversion element according to the present invention, the additive is an optional component, and it is not necessary to include additives in the hole transport layer. Even if additives are not included in the hole transport layer, the photoelectric conversion element according to the present invention can obtain high photoelectric conversion characteristics because the conductivity of the hole transport layer is good.

[0105] (Opposite poles) The counter electrode 5 is positioned opposite the conductive support 1 and formed on the hole transport layer 4, thereby enabling charge exchange with the hole transport layer. In the photoelectric conversion element according to the present invention, it is preferable to have a metal electrode as a counter electrode on the hole transport layer 4, but an electron blocking layer made of an organic material or an inorganic compound semiconductor can also be added between the hole transport layer 4 and the counter electrode 5.

[0106] For the counter electrode, it is preferable to use a material that can be formed by methods such as vapor deposition. Specifically, materials that can be used for the counter electrode include metals such as platinum, titanium, stainless steel, aluminum, gold, silver, nickel, magnesium, chromium, cobalt, and copper, as well as alloys thereof. Among these, it is preferable to use gold, silver, or silver alloys because they exhibit high electrical conductivity even in thin films. As for silver alloys, silver-gold alloys, silver-copper alloys, silver-palladium alloys, silver-copper-palladium alloys, and silver-platinum alloys are preferred because they are less susceptible to sulfidation and chlorination and improve the stability of the thin film.

[0107] When a metal electrode is used as the counter electrode, its film thickness is preferably 10 nm or more, and more preferably 50 nm or more, in order to obtain good conductivity.

[0108] In the photoelectric conversion element according to one embodiment of the present invention, the conductive support acts as the cathode and the counter electrode acts as the anode. It is preferable to irradiate the conductive support with light, such as sunlight, from the conductive support side. The photoelectric conversion layer (perovskite layer) absorbs the irradiated light and becomes excited, generating electrons and holes. The electrons then move to the electrodes via the electron transport layer, and the holes move via the hole transport layer, respectively, causing an electric current to flow and enabling the element to function as a photoelectric conversion element.

[0109] When evaluating the performance (characteristics) of a photoelectric conversion element, the short-circuit current density, open-circuit voltage, fill factor (FF), and photoelectric conversion efficiency are measured. Short-circuit current density is the 1 cm³ current flowing between the two terminals when the output terminals are short-circuited. 2 The current per watt is expressed, and the open-circuit voltage is the voltage between the two terminals when the output terminals are open-circuited. The fill factor is the value obtained by dividing the maximum output (product of current and voltage) by the product of the short-circuit current density and the open-circuit voltage, and is mainly influenced by the internal resistance. The photoelectric conversion efficiency is calculated by multiplying the maximum output (W) by 1 cm². 2 This value is obtained by dividing the value by the light intensity (W) per unit area and multiplying the result by 100 to express it as a percentage. In the element configuration of the present invention, if the initial photoelectric conversion efficiency of the photoelectric conversion element is 10% or more, it can be determined that the photoelectric conversion efficiency is good.

[0110] The photoelectric conversion element according to the present invention can be applied to solar cells, various light sensors, and the like. Perovskite solar cells are preferred as solar cells. Perovskite solar cells are formed by a photoelectric conversion element cell which has a hole transport layer containing a hole transport material with a compound represented by the general formula (1) as a hole transport layer, arranging the required number of these cells to form a module, and providing predetermined electrical wiring.

[0111] Although several preferred embodiments of the present invention have been described in detail above, it should be understood that the present invention is not limited to the embodiments described above, and that various modifications and variations are possible without departing from the spirit or scope of the appended claims. [Examples]

[0112] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples. The compounds obtained in the synthesis examples were identified using a nuclear magnetic resonance apparatus. 1 The analysis was performed using 1H-NMR (JEOL Ltd., product name: JNM-ECZ400S / L1).

[0113] [Synthesis Example 1] Synthesis of Compound (A-1) In a nitrogen atmosphere, N,N,N',N'-tetrakis(4-methoxyphenyl)-9H-carbazole-3,6-diamine (2.3 g, manufactured by Tokyo Chemical Industry Co., Ltd.), DMF (20 mL), and sodium hydride (170 mg, purity 55%, manufactured by Tokyo Chemical Industry Co., Ltd.) represented by formula (8) below were added to a reaction vessel and stirred under an ice bath for 30 minutes. Furthermore, 4,6-dichloro-2-phenylpyrimidine (400 mg, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the reaction vessel and stirred at room temperature for 8 hours. After the reaction was complete, water (100 mL) was added and the precipitated solid was filtered off. The obtained solid was recrystallized using ethyl acetate to obtain the following compound (A-1) as a pale yellow powder (yield: 1.0 g, yield: 40%). 1 H-NMR (400MHz, DMSO-d6): δ(ppm)=8.51(2H), 8.32(5H), 8.17(4H), 7.78(1H), 7.66-7.62(2H), 7.15(4H), 6.93(16H), 6.83(16H), 3.70(24H).

[0114] [ka]

[0115] [Synthesis Example 2] Synthesis of Compound (A-2) In a nitrogen atmosphere, N,N,N',N'-tetrakis(4-methoxyphenyl)-9H-carbazole-3,6-diamine (2.3 g, manufactured by Tokyo Chemical Industry Co., Ltd.), DMF (20 mL), and sodium hydride (170 mg, purity 55%, manufactured by Kanto Chemical Co., Ltd.) were added to a reaction vessel and stirred under an ice bath for 30 minutes. Furthermore, 2,6-dichloro-4-phenylpyrimidine (400 mg, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the reaction vessel and stirred at room temperature for 5 hours. After the reaction was complete, water (60 mL) was added and the precipitated solid was filtered off. The obtained solid was recrystallized using toluene / acetone to obtain the following compound (A-2) as a pale yellow powder (yield: 1.6 g, yield: 66%). 1 H-NMR (400MHz, DMSO-d6): δ(ppm)=8.81(2H), 8.38(2H), 8.08(3H), 7.64(5H), 7.56(2H), 7.25(1H), 7.17(2H), 7.05(1H), 6.93(16H), 6.83(16H), 3.70(24H).

[0116] [ka]

[0117] [Synthesis Example 3] Synthesis of Compound (A-3) In a nitrogen atmosphere, N,N,N',N'-tetrakis(4-methoxyphenyl)-9H-carbazole-3,6-diamine (3.4 g, manufactured by Tokyo Chemical Industry Co., Ltd.), DMF (30 mL), and sodium hydride (258 mg, purity 55%, manufactured by Tokyo Chemical Industry Co., Ltd.) were added to a reaction vessel and stirred under an ice bath for 30 minutes. Furthermore, 4,6-dichloropyrimidine (400 mg, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the reaction vessel and stirred at room temperature for 4 hours. After the reaction was complete, methanol (100 mL) was added and the precipitated solid was filtered off. The obtained solid was recrystallized using toluene to obtain the following compound (A-3) as a pale yellow powder (yield: 2.4 g, yield: 68%). 1H-NMR (400MHz, DMSO-d6): δ(ppm)=9.21(1H), 7.04(4H), 7.70(1H), 7.52(4H), 7.06(4H), 6.81(16H), 6.76(16H), 3.69(24H).

[0118] [ka]

[0119] [Synthesis Example 4] Synthesis of Compound (A-4) In a nitrogen atmosphere, N,N,N',N'-tetrakis(4-methoxyphenyl)-9H-carbazole-3,6-diamine (3.4 g, manufactured by Tokyo Chemical Industry Co., Ltd.), DMF (30 mL), and sodium hydride (258 mg, purity 55%, manufactured by Tokyo Chemical Industry Co., Ltd.) were added to a reaction vessel and stirred under an ice bath for 30 minutes. Furthermore, 2,4-dichloropyrimidine (400 mg, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the reaction vessel and stirred at room temperature for 3 hours. After the reaction was complete, methanol (100 mL) was added and the precipitated solid was filtered off. The obtained solid was recrystallized using toluene to obtain the following compound (A-4) as a pale yellow powder (yield: 2.2 g, yield: 61%). 1 H-NMR (400MHz, DMSO-d6): δ(ppm)=8.98(1H), 8.69(2H), 8.02(2H), 7.64(1H), 7.63(2H), 7.52(2H), 7.01(4H), 6.88(16H), 6.82(16H), 3.69(24H).

[0120] [ka]

[0121] [Synthesis Example 5] Synthesis of Compound (A-5) In a nitrogen atmosphere, N,N,N',N'-tetrakis(4-methoxyphenyl)-9H-carbazole-3,6-diamine (3.6 g, manufactured by Tokyo Chemical Industry Co., Ltd.), DMF (32 mL), and sodium hydride (270 mg, purity 55%, manufactured by Tokyo Chemical Industry Co., Ltd.) were added to a reaction vessel and stirred under an ice bath for 30 minutes. Furthermore, 4-chloro-2,6-diphenylpyrimidine (1.5 g, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the reaction vessel and stirred at room temperature for 3 hours. After the reaction was complete, methanol (100 mL) was added and the precipitated solid was filtered off. The obtained solid was recrystallized using toluene to obtain the following compound (A-5) as a pale yellow powder (yield: 3.5 g, yield: 73%). 1 H-NMR (400MHz, DMSO-d6): δ(ppm)=8.58(2H), 8.42(2H), 8.18(1H), 8.16(2 H), 7.67(2H), 7.63-7.60(6H), 7.13(2H), 6.94(8H), 6.85(8H), 3.71(12H).

[0122] [ka]

[0123] [Synthesis Example 6] Synthesis of Compound (A-6) In a nitrogen atmosphere, N,N,N',N'-tetrakis(4-methoxyphenyl)-9H-carbazole-3,6-diamine (3.6 g, manufactured by Tokyo Chemical Industry Co., Ltd.), DMF (32 mL), and sodium hydride (270 mg, purity 55%, manufactured by Tokyo Chemical Industry Co., Ltd.) were added to a reaction vessel and stirred under an ice bath for 30 minutes. Furthermore, 2-chloro-4,6-diphenylpyrimidine (1.5 g, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the reaction vessel and stirred at room temperature for 3 hours. After the reaction was complete, methanol (100 mL) was added and the precipitated solid was filtered off. The obtained solid was recrystallized using toluene to obtain the following compound (A-6) as a pale yellow powder (yield: 2.3 g, yield: 48%). 1H-NMR (400MHz, DMSO-d6): δ(ppm)=8.84(2H), 8.44-8.40(5H), 7.65-7.62(6H), 7.57(2H), 7.15(2H), 6.92(8H), 6.83(8H), 3.71(12H).

[0124] [ka]

[0125] [Synthesis Example 7] Synthesis of Compound (A-8) In a nitrogen atmosphere, N,N,N',N'-tetrakis(4-methoxyphenyl)-9H-carbazole-3,6-diamine (4.5 g, manufactured by Tokyo Chemical Industry Co., Ltd.), DMF (32 mL), and sodium hydride (335 mg, purity 55%, manufactured by Tokyo Chemical Industry Co., Ltd.) were added to a reaction vessel and stirred under an ice bath for 30 minutes. Furthermore, 2-chloropyrimidine (0.8 g, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the reaction vessel and stirred at room temperature for 3 hours. After the reaction was complete, methanol (100 mL) was added and the precipitated solid was filtered off. The obtained solid was recrystallized using toluene to obtain the following compound (A-8) as a pale yellow powder (yield: 1.8 g, yield: 36%). 1 H-NMR (400MHz, DMSO-d6): δ (ppm) = 8.91 (2H), 8.69 (2H), 7.55 (2H), 7.34 (1H), 7.10 (2H), 6.90 (8H), 6.84 (8H), 3.72 (12H).

[0126] [ka]

[0127] [Synthesis Example 8] Synthesis of compound (A-15) In a nitrogen atmosphere, N,N,N',N'-tetrakis(4-methoxyphenyl)-9H-carbazole-3,6-diamine (2.3 g, manufactured by Tokyo Chemical Industry Co., Ltd.), DMF (32 mL), and sodium hydride (170 mg, purity 55%, manufactured by Tokyo Chemical Industry Co., Ltd.) were added to a reaction vessel and stirred in an ice bath for 30 minutes. Furthermore, 2,4-dichloro-6-(4-pyridyl)pyrimidine (0.4 g, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the reaction vessel and stirred at room temperature for 7 hours. After the reaction was complete, water (100 mL) was added and the precipitated solid was filtered off. The obtained solid was recrystallized using toluene to obtain the following compound (A-15) as a yellow powder (yield: 0.6 g, yield: 24%). 1 H-NMR (400MHz, THF-d8): δ(ppm)=8.94(1H), 8.09(3H), 7.72(1H), 7.63(3H), 7.54(1H), 7.21-7.09(6H), 7.01-6.92(18H), 6.75(16H), 3.71(24H).

[0128] [ka]

[0129] [Synthesis Example 9] Synthesis of compound (A-22) In a nitrogen atmosphere, N,N,N',N'-tetrakis(4-methoxyphenyl)-9H-carbazole-3,6-diamine (2.8 g, manufactured by Tokyo Chemical Industry Co., Ltd.), DMF (32 mL), potassium carbonate (670 mg, manufactured by Junsei Chemical Co., Ltd.), and 4,6-dichloro-2-(methylthio)pyrimidine (0.4 g, manufactured by Tokyo Chemical Industry Co., Ltd.) were added to a reaction vessel and stirred at 70°C for 7 hours. After the reaction was complete, water (100 mL) was added and the precipitated solid was filtered off. The obtained solid was recrystallized using acetone to obtain the following compound (A-22) as a yellow powder (yield: 1.1 g, yield: 37%). 1H-NMR (400MHz, DMSO-d6): δ(ppm)=8.02(4H), 7.54(4H), 7.44(1H), 7.07(4H), 6.85(16H), 6.79(16H), 3.68(24H), 2.65(3H).

[0130] [ka]

[0131] [Synthesis Example 10] Synthesis of compound (A-23) In a nitrogen atmosphere, N,N,N',N'-tetrakis(4-methoxyphenyl)-9H-carbazole-3,6-diamine (2.8 g, manufactured by Tokyo Chemical Industry Co., Ltd.), DMF (32 mL), potassium carbonate (670 mg, manufactured by Junsei Chemical Co., Ltd.), and 4,6-dichloro-2-(methylthio)pyrimidine (0.4 g, manufactured by Tokyo Chemical Industry Co., Ltd.) were added to a reaction vessel and stirred at 70°C for 7 hours. After the reaction was complete, water (100 mL) was added and the precipitated solid was filtered off. The obtained solid was subjected to silica gel column chromatography under air with toluene as the solvent. The fraction containing compound (A-23) was collected and allowed to dry to obtain the following compound (A-23) as a yellow powder (yield: 0.4 g, yield: 13%). 1 H-NMR (400MHz, DMSO-d6): δ (ppm) = 8.03 (4H), 7.58-7.56 (5H), 7.06 (4H), 6.91 (16H), 6.85 (16H), 3.71 (24H), 2.61 (3H).

[0132] [ka]

[0133] [Example 1] Fabrication and evaluation of a photoelectric conversion element A glass coated with a flat ITO film (conductive support 1, trade name, manufactured by Geomatec) was ultrasonically cleaned with isopropyl alcohol and then treated with UV ozone. Under a dry atmosphere with a relative humidity of 10% RH or less, a coating solution for the electron transport layer, Tin(IV) oxide, 15% in H2O colloidal dispersion (trade name, manufactured by Alfa Aesar), was spin-coated onto the ITO film to form a coated film. Subsequently, the coated film was 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 20 nm.

[0134] Under a dry atmosphere with a relative humidity of 10% RH or less, formamidine hydroiodide (1M, manufactured by Tokyo Chemical Industry Co., Ltd.), lead(II) iodide (1.1M, manufactured by Tokyo Chemical Industry Co., Ltd.), methylamine hydrobromide (0.2M, manufactured by Tokyo Chemical Industry Co., Ltd.), and lead(II) bromide (0.2M, manufactured by Tokyo Chemical Industry Co., Ltd.) were dissolved in a mixed solvent of dimethylformamide and dimethyl sulfoxide (volume ratio 4:1). To this, a dimethyl sulfoxide solution of cesium iodide (1.5M, manufactured by Tokyo Chemical Industry Co., Ltd.) was added so that the amount of cesium added was 5 mol% in the composition ratio, and a perovskite precursor solution was prepared. Under a dry atmosphere with a relative humidity of 10% RH or less, the prepared perovskite precursor solution was dropped onto a tin oxide layer (electron transport layer 2) and spin-coated. During spin-coating, 0.35 mL of chlorobenzene was added to form a perovskite precursor coating. Subsequently, the coating was heated at 100°C for 1 hour using a hot plate to form a Cs(MAFA)Pb(IBr) 3-layer (photoelectric conversion layer 3) with a thickness of approximately 500 nm.

[0135] Under a dry atmosphere with a relative humidity of 10% RH or less, bis(trifluoromethanesulfonyl)imide lithium was dissolved in acetonitrile at a concentration of 1.8 M to prepare a dopant solution. Compound (A-1) obtained in Synthesis Example 1 was added to chlorobenzene to a concentration of 32 mM as a hole transport material and dissolved at 80°C to obtain a prepared solution. After cooling the prepared solution, 4-tert-butylpyridine was added to the prepared solution so that the amount of 4-tert-butylpyridine was 3.3 equivalents relative to compound (A-1). Furthermore, the above dopant solution was added so that the amount of bis(trifluoromethanesulfonyl)imide lithium was 0.5 equivalents relative to compound (A-1) to prepare a coating solution for the hole transport layer. Under a dry atmosphere with a relative humidity of 10%RH or less, a hole transport layer coating solution was spin-coated onto three layers of Cs(MAFA)Pb(IBr) (photoelectric conversion layer 3) to form a hole transport layer 4 with a thickness of approximately 100 nm.

[0136] On the hole transport layer 4, a vacuum deposition method was used to create a vacuum of approximately 1 × 10⁻⁶. -4 A gold electrode (counter electrode 5) was formed by depositing a gold film of approximately 80 nm in Pa, and a photoelectric conversion element was fabricated.

[0137] Simulated sunlight (AM1.5, 1000W / m²) generated using a white light irradiation device (manufactured by Spectrometer Co., Ltd., product name: OTENTO-SUN SH type) 2 The photoelectric conversion element was irradiated with a light source from the conductive support side, and the current-voltage characteristics were measured using a source meter (KEITHLEY, product name: Model 2400 Series SourceMeter). As a result, the short-circuit current density Jsc [mA / cm²] was obtained. 2 The open-circuit voltage Voc[V] and curve factor FF were obtained, and the initial photoelectric conversion efficiency PCE[%] was calculated. The results are shown in Table 1. Note that the results shown in Table 1 are normalized based on the results of Comparative Example 1, which will be described later.

[0138] [Example 2] In preparing the coating solution for the hole transport layer, a photoelectric conversion element was fabricated in the same manner as in Example 1, except that the dopant solutions of 4-tert-butylpyridine and bis(trifluoromethanesulfonyl)imide lithium were not added. The initial photoelectric conversion efficiency was obtained in the same manner as in Example 1. The results are shown in Table 2. Note that the results shown in Table 2 are normalized based on the results of Comparative Example 2, which will be described later.

[0139] [Example 3] A photoelectric conversion element was fabricated in the same manner as in Example 1, except that compound (A-2) was dissolved in chlorobenzene to a concentration of 32 mM and used instead of compound (A-1), and the initial photoelectric conversion efficiency was obtained in the same manner as in Example 1. The results are shown in Table 1.

[0140] [Example 4] In preparing the coating solution for the hole transport layer, a photoelectric conversion element was fabricated in the same manner as in Example 3, except that the dopant solutions of 4-tert-butylpyridine and bis(trifluoromethanesulfonyl)imide lithium were not added, and the initial photoelectric conversion efficiency was obtained in the same manner as in Example 1. The results are shown in Table 2.

[0141] [Example 5] A photoelectric conversion element was fabricated in the same manner as in Example 1, except that compound (A-3) was dissolved at room temperature to a concentration of 34 mM instead of compound (A-1), and the initial photoelectric conversion efficiency was obtained in the same manner as in Example 1. The results are shown in Table 1.

[0142] [Example 6] In preparing the coating solution for the hole transport layer, a photoelectric conversion element was fabricated in the same manner as in Example 5, except that the dopant solutions of 4-tert-butylpyridine and bis(trifluoromethanesulfonyl)imide lithium were not added, and the initial photoelectric conversion efficiency was obtained in the same manner as in Example 1. The results are shown in Table 2.

[0143] [Example 7] A photoelectric conversion element was fabricated in the same manner as in Example 1, except that compound (A-4) was dissolved at room temperature to a concentration of 34 mM instead of compound (A-1), and the initial photoelectric conversion efficiency was obtained in the same manner as in Example 1. The results are shown in Table 1.

[0144] [Example 8] In the preparation of the coating solution for the hole transport layer, a photoelectric conversion element was fabricated in the same manner as in Example 7, except that the dopant solutions of 4-tert-butylpyridine and bis(trifluoromethanesulfonyl)imide lithium were not added, and the initial photoelectric conversion efficiency was obtained in the same manner as in Example 1. The results are shown in Table 2.

[0145] [Example 9] A photoelectric conversion element was fabricated in the same manner as in Example 1, except that compound (A-5) was dissolved at room temperature to a concentration of 53 mM instead of compound (A-1), and the initial photoelectric conversion efficiency was obtained in the same manner as in Example 1. The results are shown in Table 1.

[0146] [Example 10] In the preparation of the coating solution for the hole transport layer, a photoelectric conversion element was fabricated in the same manner as in Example 9, except that the dopant solutions of 4-tert-butylpyridine and bis(trifluoromethanesulfonyl)imide lithium were not added, and the initial photoelectric conversion efficiency was obtained in the same manner as in Example 1. The results are shown in Table 2.

[0147] [Example 11] A photoelectric conversion element was fabricated in the same manner as in Example 1, except that compound (A-6) was dissolved at room temperature to a concentration of 53 mM instead of compound (A-1), and the initial photoelectric conversion efficiency was obtained in the same manner as in Example 1. The results are shown in Table 1.

[0148] [Example 12] In preparing the coating solution for the hole transport layer, a photoelectric conversion element was fabricated in the same manner as in Example 11, except that the dopant solutions of 4-tert-butylpyridine and bis(trifluoromethanesulfonyl)imide lithium were not added, and the initial photoelectric conversion efficiency was obtained in the same manner as in Example 1. The results are shown in Table 2.

[0149] [Example 13] A photoelectric conversion element was fabricated in the same manner as in Example 1, except that compound (A-8) was dissolved at room temperature to a concentration of 64 mM instead of compound (A-1), and the initial photoelectric conversion efficiency was obtained in the same manner as in Example 1. The results are shown in Table 1.

[0150] [Example 14] In preparing the coating solution for the hole transport layer, a photoelectric conversion element was fabricated in the same manner as in Example 13, except that the dopant solutions of 4-tert-butylpyridine and bis(trifluoromethanesulfonyl)imide lithium were not added, and the initial photoelectric conversion efficiency was obtained in the same manner as in Example 1. The results are shown in Table 2.

[0151] [Example 15] A photoelectric conversion element was fabricated in the same manner as in Example 1, except that compound (A-15) was dissolved at room temperature to a concentration of 32 mM instead of compound (A-1), and the initial photoelectric conversion efficiency was obtained in the same manner as in Example 1. The results are shown in Table 1.

[0152] [Example 16] In the preparation of the coating solution for the hole transport layer, a photoelectric conversion element was fabricated in the same manner as in Example 15, except that the dopant solutions of 4-tert-butylpyridine and bis(trifluoromethanesulfonyl)imide lithium were not added, and the initial photoelectric conversion efficiency was obtained in the same manner as in Example 1. The results are shown in Table 2.

[0153] [Example 17] A photoelectric conversion element was fabricated in the same manner as in Example 1, except that compound (A-22) was dissolved at room temperature to a concentration of 33 mM instead of compound (A-1), and the initial photoelectric conversion efficiency was obtained in the same manner as in Example 1. The results are shown in Table 1.

[0154] [Example 18] In the preparation of the coating solution for the hole transport layer, a photoelectric conversion device was fabricated in the same manner as in Example 17 except that the dopant solution of 4-tert-butylpyridine and lithium bis(trifluoromethanesulfonyl)imide was not added, and the initial photoelectric conversion efficiency was obtained in the same manner as in Example 1. The results are shown in Table 2.

[0155] [Example 19] A photoelectric conversion device was fabricated in the same manner as in Example 1 except that Compound (A-23) was dissolved at room temperature to a concentration of 33 mM instead of Compound (A-1), and the initial photoelectric conversion efficiency was obtained in the same manner as in Example 1. The results are shown in Table 1.

[0156] [Comparative Example 1] A photoelectric conversion device was fabricated in the same manner as in Example 1 except that Spiro-OMeTAD (manufactured by Sigma-Aldrich, the following Comparative Compound (B-1)), a standard hole transport material, was dissolved at room temperature to a concentration of 70 mM instead of Compound (A-1), and the initial photoelectric conversion efficiency was obtained in the same manner as in Example 1. The results are shown in Table 1. As described above, in Table 1, Comparative Example 1 is an example serving as a reference when normalizing the results of each example. Therefore, the results of Comparative Example 1 are "1.00" for all evaluation items.

[0157] [Chemical formula]

[0158] [Comparative Example 2] A photoelectric conversion device was fabricated in the same manner as in Comparative Example 1 except that the dopant solution of 4-tert-butylpyridine and lithium bis(trifluoromethanesulfonyl)imide was not added, and the initial photoelectric conversion efficiency was obtained in the same manner as in Example 1. The results are shown in Table 2. As described above, in Table 2, Comparative Example 2 is an example serving as a reference when normalizing the results of each example. Therefore, the results of Comparative Example 2 are "1.00" for all evaluation items.

[0159] [Table 1]

[0160]

Table 2

[0161] From the results in Table 1, it was found that the photoelectric conversion device according to the example using the compound according to the present invention represented by the general formula (1) as a hole transport material exhibited equivalent or superior photoelectric conversion efficiency compared to the photoelectric conversion device according to the comparative example using the comparative compound (B-1) which is a conventional standard hole transport material. In particular, from the results in Table 2, when no additive was used, this tendency was remarkable. Incidentally, the actual initial photoelectric conversion efficiency is a value sufficiently exceeding 10%, and even if it is a result equivalent to that of the comparative example, the initial photoelectric conversion efficiency is sufficiently high.

[0162] After obtaining the above initial photoelectric conversion efficiency, the photoelectric conversion devices according to Examples 1 to 8, 11, 12, and 14 to 18, and Comparative Examples 1 and 2 were respectively placed in a vacuum isothermal dryer (manufactured by Tokyo Rikakikai Co., Ltd., product name: VOS-310C) and stored at 85°C for 1,000 hours. After storage, in the same manner as in Example 1 above, the current-voltage characteristics were measured again under pseudo-solar light irradiation to obtain the photoelectric conversion efficiency after heating for 1,000 hours. Using the above initial photoelectric conversion efficiency and the obtained photoelectric conversion efficiency after heating for 1,000 hours, the retention rate (%) was calculated from the following formula (a-1). The results are shown in Table 3 and Table 4.

[0163]

Equation

[0164]

Table 3

[0165]

Table 4

[0166] The results in Tables 3 and 4 show that the photoelectric conversion element in the example using the compound according to the present invention represented by general formula (1) as a hole transport material maintained a high photoelectric conversion efficiency even after 1,000 hours of heating, compared to the photoelectric conversion element in the comparative example using comparative compound (B-1), which is a conventional standard hole transport material, indicating excellent heat resistance. This trend was particularly pronounced when no additives were used (Table 4). [Industrial applicability]

[0167] By using the compound of the present invention, represented by general formula (1), as a hole transport material for a photoelectric conversion element, a photoelectric conversion element with excellent photoelectric conversion efficiency and heat resistance was obtained. By using this photoelectric conversion element as a solar cell, it becomes possible to efficiently convert solar energy into electrical energy, thereby providing clean energy. Therefore, the present invention has high industrial applicability. [Explanation of Symbols]

[0168] 1. Conductive support 2 Electron transport layer 3. Photoelectric conversion layer 4. Hole transport layer 5 Opposites

Claims

1. Compounds represented by the following general formula (1): 【Chemistry 1】 In general formula (1), L １ ~L ３ Each of them operates independently. The group represented by the following general formula (2), hydrogen atom, halogen atom, hydroxyl group, Linear or branched alkyl groups having 1 to 20 carbon atoms, which may have substituents. A linear or branched alkenyl group having 2 to 20 carbon atoms, which may have substituents. A linear or branched alkoxy group having 1 to 20 carbon atoms, which may have substituents. A aryloxy group having 6 to 30 carbon atoms, which may have substituents. An amino group having 0 to 50 carbon atoms, which may have substituents. A thio group having 0 to 20 carbon atoms, which may have substituents. A alkylsulfinyl group having 1 to 20 carbon atoms, which may have substituents. A alkylsulfonyl group having 1 to 20 carbon atoms, which may have substituents. A substituted aromatic hydrocarbon group having 6 to 30 carbon atoms, or A heterocyclic group having 5 to 30 ring-forming atoms, which may have substituents. L １ ~L ３ At least one of them is a group represented by the following general formula (2): 【Chemistry 2】 In general formula (2), R １ ~R ２０ Each of them operates independently. hydrogen atom, Linear or branched alkyl groups having 1 to 20 carbon atoms, which may have substituents. A linear or branched alkenyl group having 2 to 20 carbon atoms, which may have substituents. A cycloalkyl group having 3 to 10 carbon atoms, which may have substituents. A linear or branched alkoxy group having 1 to 20 carbon atoms, which may have substituents. An aryloxy group having 6 to 30 carbon atoms, which may have substituents. An amino group having 0 to 20 carbon atoms, which may have substituents, or A thio group having 0 to 20 carbon atoms, which may have substituents. A １ ~A ３ represents a nitrogen atom or C(R １ａ ), and any two of A １ ~A ３ are nitrogen atoms, R １ａ teeth, hydrogen atom, Linear or branched alkyl groups having 1 to 20 carbon atoms, which may have substituents. A linear or branched alkenyl group having 2 to 20 carbon atoms, which may have substituents. A cycloalkyl group having 3 to 10 carbon atoms, which may have substituents. A linear or branched alkoxy group having 1 to 20 carbon atoms, which may have substituents. An aryloxy group having 6 to 30 carbon atoms, which may have substituents. An amino group having 0 to 20 carbon atoms, which may have substituents, or A thio group having 0 to 20 carbon atoms, which may have substituents.

2. In the above general formula (1), L １ but, hydrogen atom, An amino group having 0 to 50 carbon atoms, which may have substituents. A thio group having 0 to 20 carbon atoms, which may have substituents. A alkylsulfinyl group having 1 to 20 carbon atoms, which may have substituents. A alkylsulfonyl group having 1 to 20 carbon atoms, which may have substituents. A substituted aromatic hydrocarbon group having 6 to 20 carbon atoms, or The compound according to claim 1, wherein the heterocyclic group has 5 to 30 ring-forming atoms, which may have substituents.

3. The compound according to claim 1, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (3) or general formula (4): 【Transformation 3】 In general formulas (3) and (4), L １ , L ２ A １ ~A ３ , and R １ ~R ２０ These are defined in the general formulas (1) and (2) above, respectively, except that L in general formula (3) １ and L ２ This represents a group other than the one represented by the general formula (2), and L in the general formula (4). １ This represents a group other than the one represented by the general formula (2) above.

4. In the above general formula (2), R １ ~R ２０ The compound according to claim 1, wherein the compound is a linear or branched alkoxy group having 1 to 20 carbon atoms, which may have hydrogen atoms or substituents.

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

6. A photoelectric conversion element using the hole transport material described in claim 5.

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