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

Abstract

A photoelectric conversion element in which a compound represented by general formula (1) is used in a hole transport layer has excellent heat resistance. R1 represents an aromatic hydrocarbon group, a heterocyclic group or the like, and R2-R29 represent a hydrogen atom, an alkoxy group or the like.

Description

Technical Field

[0001] This 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, as a clean energy source, has received much attention, and solar cells are being actively developed. Among them, the development of perovskite solar cells (hereinafter referred to as perovskite solar cells), which are low-cost next-generation solar cells that can be manufactured through solution processes, has attracted attention (e.g., Patent Document 1, Non-Patent Documents 1-2).

[0003] In perovskite solar cells, hole transport materials are mostly used in the elements. The purposes of use include: (1) improving the selective transport of holes to increase photoelectric conversion efficiency, and (2) protecting the perovskite material, which is bonded to the perovskite photoelectric conversion layer and is susceptible to the effects of moisture or oxygen (e.g., Non-Patent Literature 3). Spiro-OMeTAD [Comparative Compound (B-1) described later], a spirodioxanone-based organic compound, is commonly used as a standard hole transport material; however, there are fewer reports of hole transport materials that contribute more to photoelectric conversion characteristics than this material. Furthermore, since photoelectric conversion elements are expected to be used outdoors under sunlight, high heat resistance is required. Previous technical documents Patent documents

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

[0005] Non-patent literature 1: J. Am. Chem. Soc., 2009, Vol. 131, pp. 6050-6051. Non-patent literature 2: Science, 2012, Vol. 388, pp. 643-647 Non-patent literature 3: Chem. Sci., 2019, 10, pp. 6748-6769. Summary of the Invention The technical problem to be solved by the invention

[0006] 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 capable of efficiently outputting current, a photoelectric conversion element with high heat resistance for using the compound in a hole transport layer, and a solar cell. means for solving technical problems

[0007] To address the aforementioned issues, the inventors conducted in-depth research on improving photoelectric conversion characteristics and discovered the following: by designing and developing compounds with specific structures and using them as hole transport layers in photoelectric conversion elements, photoelectric conversion elements with excellent photoelectric conversion characteristics and high heat resistance, as well as perovskite solar cells, can be obtained. In other words, the essence of this invention is as follows.

[0008] 1. A compound represented by the following general formula (1).

[0009] [Chemical Formula 1]

[0010] In the formula, R 1 Represents hydrogen atom, halogen atom, hydroxyl group, The following groups may have substituents: a straight-chain or branched alkyl group with 1 to 20 carbon atoms; a straight-chain or branched alkenyl group with 2 to 20 carbon atoms; a straight-chain or branched alkoxy group with 1 to 20 carbon atoms; an aryloxy group with 6 to 30 carbon atoms; an amino group with 0 to 60 carbon atoms; a thio group with 0 to 20 carbon atoms; a monovalent aromatic hydrocarbon group with 6 to 30 carbon atoms; or a monovalent heterocyclic group with 5 to 30 ring-forming atoms. R 2 ~R 29 Represented independently hydrogen atom, Alkyl groups having 1 to 20 carbon atoms that may have substituents, either straight-chain or branched; alkenyl groups having 2 to 20 carbon atoms that may have substituents, either straight-chain or branched; cycloalkyl groups having 3 to 12 carbon atoms that may have substituents; alkoxy groups having 1 to 20 carbon atoms that may have substituents; amino groups having 0 to 20 carbon atoms that may have substituents; or... It can have a thio group with 0 to 20 carbon atoms as a substituent. R 10 and R 11 R 24 and R 25 They can bond together to form a ring.

[0011] 2. According to the above compounds, wherein, In the general formula (1), R 1 It can be a halogen atom, an amino group with 0 to 60 carbon atoms that may have substituents, an aromatic hydrocarbon group with 6 to 20 carbon atoms that may have substituents, or a monovalent heterocyclic group with 5 to 30 ring-forming atoms that may have substituents.

[0012] 3. According to the above compounds, wherein, In the general formula (1), R 6 ~R 15 and R 20 ~R 29 At least one of them is a straight-chain or branched alkoxy group having 1 to 20 carbon atoms and may have substituents.

[0013] 4. According to the above compounds, wherein, In the general formula (1), R 10 and R 11 R 24 and R 25 None of them bonded together to form a ring.

[0014] 5. A hole transport material comprising the compound described above.

[0015] 6. The hole transport material described above is used as a hole transport layer in a photoelectric conversion element.

[0016] 7. A photoelectric conversion element having a hole transport layer comprising the compound described above.

[0017] 8. A solar cell that uses the photoelectric conversion element described above. Invention Effects

[0018] According to the compound of the present invention and the hole transport layer using the compound, it is possible to obtain photoelectric conversion elements and perovskite solar cells with high heat resistance. Attached Figure Description

[0019] Figure 1 A schematic cross-sectional view showing the structure of the photoelectric conversion element of the embodiments and comparative examples of the present invention. Detailed Implementation

[0020] The present invention will now be described in detail. The descriptions of the constituent elements described below are sometimes based on representative embodiments or specific examples of the present invention, but the present invention is not limited to such embodiments or specific examples. Furthermore, in this specification, the numerical range indicated by “~” refers to the range encompassed by the values ​​before and after “~” as the lower and upper limits. Moreover, the compound represented by general formula (1), R… 1 ~R 29 Some or all of the hydrogen atoms present in the indicated group can be replaced by deuterium atoms. In this specification, "transparent" and "transmittance" refer to a transmittance of 50% or more for photoelectric conversion, such as 80% or more, 90% or more, or 99% or more. Transmittance can be measured using a UV-Vis spectrophotometer.

[0021] Hereinafter, the compounds of the present invention represented by the general formula (1) will be specifically described, but the present invention should not be interpreted as limiting by these specific descriptions.

[0022] In the general formula (1), R 1 Represents hydrogen atom, halogen atom, hydroxyl group, Alkyl groups, which may have 1 to 20 carbon atoms and be straight-chain or branched, may have substituents. Alkenes with 2 to 20 carbon atoms that can have substituents are either straight-chain or branched. Alkoxy groups, which may have 1 to 20 carbon atoms and be straight-chain or branched, can have substituents. Aryloxy groups with 6 to 30 carbon atoms that can have substituents Amino groups with 0 to 60 carbon atoms that can have substituents It can have a thio group with 0 to 20 carbon atoms as a substituent. It may have an aromatic hydrocarbon group with 6 to 30 carbon atoms as a substituent, or Rings with substituents can form heterocyclic groups with 5 to 30 atoms.

[0023] In general formula (1), as R 1 Examples of "halogen atoms" include fluorine, chlorine, bromine, and iodine atoms.

[0024] In general formula (1), R 1 The "linear or branched alkyl group having 1 to 20 carbon atoms" in the phrase "linear or branched alkyl group having 1 to 20 carbon atoms" is selected from the range of 1 to 20, for example, from the range of 1 to 12, or from the range of 1 to 6. Specifically, examples of "linear or branched alkyl group having 1 to 20 carbon atoms" include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, 2-ethylhexyl, heptyl, octyl, isooctyl, nonyl, decyl, etc.

[0025] In general formula (1), R 1The "alkenyl group with 2 to 20 carbon atoms" in the phrase "a straight-chain or branched alkenyl group that may have substituents" refers to an alkenyl group with 2 to 20 carbon atoms, specifically those ranging from 2 to 20, such as 2 to 12, or 2 to 6. Examples of "alkynyl groups with 2 to 20 carbon atoms" include vinyl, 1-propenyl, 2-propenyl (allyl), 1-methylvinyl, 1-butenyl, 2-butenyl, 1-pentenyl, 1-hexenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, 1-ethylvinyl, or alkenyl groups with 2 to 20 carbon atoms bonded together.

[0026] In general formula (1), R 1 The "linear or branched alkoxy group having 1 to 20 carbon atoms" in the phrase "linear or branched alkoxy group having 1 to 20 carbon atoms" is selected from the range of 1 to 20, for example, from the range of 1 to 12, or from the range of 1 to 6. Specifically, examples of "linear or branched alkoxy group having 1 to 20 carbon atoms" include methoxy, ethoxy, propoxy, n-butoxy, n-pentoxy, n-hexoxy, heptoxy, octoxy, nonoxy, decoxy, isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isooctoxy, and tert-octoxy.

[0027] In general formula (1), regarding R 1 For an explanation and specific examples of the aryl group bonded to the oxygen group in the phrase "aryloxy group with 6 to 30 carbon atoms that may have substituents," please refer to the description of "monovalent aromatic hydrocarbon group with 6 to 30 carbon atoms" below. Specifically, examples of "aryloxy group with 6 to 30 carbon atoms" include phenoxy, toluoxy, biphenyloxy, terphenyloxy, naphthoxy, anthraceneoxy, phenanthroxy, phenoxy, indoxy, etc.

[0028] In general formula (1), R 1The phrase "amino group with 0 to 60 carbon atoms that may have substituents" can refer to an unsubstituted amino group, a monosubstituted amino group, or a disubstituted amino group. Examples of substituents for each substituted amino group include alkyl, aryl, and acyl groups. The hydrogen atoms of these groups can be substituted by substituents selected from substituent group A below. For descriptions and specific examples of alkyl groups and alkyl groups constituting acyl groups, please refer to the description of "linear or branched alkyl groups with 1 to 20 carbon atoms" above. For descriptions and specific examples of aryl groups, please refer to the description of "monovalent aromatic hydrocarbon groups with 6 to 30 carbon atoms" below. Furthermore, in disubstituted amino groups, the two substituents bonded to the nitrogen atom do not bond to each other to form a cyclic structure; groups having such cyclic structures are included in the "heterocyclic groups" described later in this invention. The number of carbon atoms in "amino group with 0 to 60 carbon atoms" is selected from the range of 0 to 60, for example, it can be selected from the range of 0 to 30, for example, it can be selected from the range of 2 to 11, and for example, it can be selected from the range of 12 to 24. Specifically, examples of "amino group with 0 to 60 carbon atoms" include unsubstituted amino groups (-NH2), monosubstituted amino groups such as methylamino, ethylamino, acetamino, and phenylamino, and disubstituted amino groups such as dimethylamino, diethylamino, dialkylamino, diphenylamino, and acetylphenylamino. In one aspect of the present invention, "amino group with 0 to 60 carbon atoms that may have substituents" is an amino group with 0 to 60 carbon atoms that can be substituted with alkyl or aryl groups.

[0029] In general formula (1), R 1 The phrase "thiogroup with 0 to 20 carbon atoms" in the expression "thiogroup with 0 to 20 carbon atoms that may have substituents" can be an unsubstituted thiogroup (thiol group: -SH) or a substituted thiogroup formed by substituting a hydrogen atom of a thiol group with a substituent. The number of carbon atoms in the substituted thiogroup is preferably in the range of 1 to 18, for example, in the range of 1 to 12, or for example, in the range of 1 to 6. Examples of substituents for the substituted thiogroup include alkyl and aryl groups, the hydrogen atoms of which can be replaced by substituents selected from substituent group A below. For a description and specific examples of alkyl groups as substituents for thiogroups, please refer to the description of "linear or branched alkyl groups with 1 to 20 carbon atoms" above; for a description and specific examples of aryl groups, please refer to the description of "monovalent aromatic hydrocarbon groups with 6 to 30 carbon atoms" below. Typical examples of substituted thio groups include straight-chain or branched alkylthio groups with 1 to 20 carbon atoms that may have substituents, and arylthio groups with 6 to 30 carbon atoms that may have substituents. Specifically, examples of "thio groups with 0 to 20 carbon atoms" include unsubstituted thio groups (thiols: -SH), alkylthio groups (e.g., methylthio, ethylthio, propylthio), and arylthio groups (e.g., phenylthio, biphenylthio).

[0030] In general formula (1), R 1 The aromatic ring constituting the "monovalent aromatic hydrocarbon group with 6 to 30 carbon atoms having substituents" can be a monocyclic ring, a condensed ring formed by the condensation of two or more rings, or a linked ring formed by two or more rings linked by a single bond. In the case of a condensed ring, the number of condensed rings is, for example, 2 to 6, or 2 to 4. In one aspect of the invention, the aromatic ring comprises two or more rings. In the case of a condensed ring, it is called a "condensed polycyclic aromatic group". In the case of a linked ring, the number of linked rings is, for example, 2 to 6, or 2 to 4. The number of carbon atoms forming the aromatic ring is selected from the range of 6 to 30, for example, from the range of 6 to 22 or 6 to 18, or for example, from the range of 6 to 14 or 6 to 10. As "a 1-valent aromatic hydrocarbon group with 6 to 30 carbon atoms", examples include phenyl, biphenyl, terphenyl, naphthyl, anthracenyl group, phenanthryl, fumonyl, indyl, pyrene, peryl, fluoranthenyl group, and triphenyl group.

[0031] In general formula (1), R 1The heterocycle constituting the "monocyclic heterocycle with 5 to 30 ring-forming atoms" in the phrase "a monovalent heterocyclic group having 5 to 30 ring-forming atoms" can be a monocyclic ring or a condensed ring formed by the condensation of two or more rings. In the case of a condensed ring, the number of condensed rings is, for example, 2 to 6, or 2 to 4. Furthermore, the heterocycle can be an aromatic heterocycle or an aliphatic heterocycle. In one aspect of the invention, the heterocycle comprises two or more rings. Examples of heteroatoms constituting the heterocycle include nitrogen atoms, oxygen atoms, and sulfur atoms. The number of ring-forming atoms in an aromatic heterocycle is selected from the range of 5 to 30, and for example, from the range of 5 to 18. Among the "monocyclic heterocyclic groups with 5 to 30 atoms forming a ring," aromatic heterocyclic groups can specifically include pyridyl, pyrimidinyl, triazine, thiophene, furanyl (furyl group), pyrroloyl, imidazolyl, pyrazolyl, triazolyl, quinolinyl, isoquinolinyl, naphridyl, acridine, phenanthrolinyl (phenanthrolinyl group), benzofuranyl, benzothiophene, oxazolyl, indole, carbazole, benzooxazolyl, thiazolyl, benzothiazolyl, quinoxalinyl, benzimidazolyl, dibenzofuranyl, dibenzothiophene, carbonyl, etc. The bonding position of these groups is not particularly limited; for example, if it is pyridyl, it can be any one of 2-pyridyl, 3-pyridyl, or 4-pyridyl (for example, 4-pyridyl can be chosen). In one aspect of the present invention, the aromatic heterocyclic group is bonded via carbon atoms. In another aspect of the present invention, the aromatic heterocyclic group is bonded via nitrogen atoms. Among the "monocyclic groups with 5 to 30 ring atoms in a monovalent form," aliphatic heterocyclic groups are specifically exemplified, such as morpholino, pyrrolidino group, piperidinyl, piperazine, etc., which are bonded via nitrogen atoms, or tetrahydrofuranyl group, tetrahydrothienyl group, etc., which are bonded via carbon atoms. In one aspect of the present invention, R... 1 The term "monocyclic heterocyclic group with 5 to 30 ring-forming atoms that may have substituents" can be a monovalent aromatic heterocyclic group with 5 to 30 ring-forming atoms that may have substituents and is bonded by a nitrogen atom, or a monovalent aliphatic heterocyclic group with 5 to 30 ring-forming atoms that may have substituents. For example, R 1 The term "monovalent heterocyclic group with 5 to 30 ring-forming atoms that can have substituents" can be defined as a monovalent aromatic heterocyclic group with 5 to 30 ring-forming atoms bonded by nitrogen atoms. It can be classified into groups consisting of substituted or unsubstituted carbazole-9-yl groups and other groups. For example, R... 1The “monocyclic heterocyclic group with 5 to 30 ring-forming atoms that can have substituents” can be an aliphatic heterocyclic group with 5 to 30 ring-forming atoms that can have substituents, especially a monocyclic aliphatic heterocyclic group with 5 to 30 ring-forming atoms that can have substituents bonded by nitrogen atoms.

[0032] In general formula (1), as R 1The terms "linear or branched alkyl group having 1 to 20 carbon atoms that may have substituents", "linear or branched alkenyl group having 2 to 20 carbon atoms that may have substituents", "linear or branched alkoxy group having 1 to 20 carbon atoms that may have substituents", "aryloxy group having 6 to 30 carbon atoms that may have substituents", "amino group having 1 to 60 carbon atoms that may have substituents", "thio group having 0 to 20 carbon atoms that may have substituents", "monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms that may have substituents", or "a ring-forming group having 5 carbon atoms that may have substituents" are used to indicate the following: The "substituents" in "heterocyclic groups with a valence of ~30" specifically include halogen atoms such as fluorine, chlorine, bromine, and iodine; cyano; hydroxyl; nitro; nitroso; carboxyl; phosphate; thio (>C=S); trimethylsilyl; carboxylic acid esters such as methyl ester and ethyl ester; straight-chain or branched alkyl groups with 1 to 18 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, 2-ethylhexyl, heptyl, octyl, isooctyl, nonyl, and decyl; and vinyl groups. Alkenyl groups with 2 to 18 carbon atoms, including vinyl, 1-propenyl, 2-propenyl (allyl), 1-butenyl, 2-butenyl, 1-pentenyl, 1-hexenyl, 2-methyl-1-propenyl, 2-methyl-2-propenyl, and 1-ethyl vinyl; alkoxy groups with 1 to 18 carbon atoms, including methoxy, ethoxy, propoxy, tert-butoxy, pentoxy, and hexoxy; aromatic hydrocarbon groups with 6 to 30 carbon atoms, including phenyl, naphthyl, anthracene, phenanthryl, and pyrene; and pyridyl, pyrimidinyl, triazine, thiophene, furanyl, pyrroloyl, imidazolyl, pyrazolyl, triazolyl, quinolinyl, isoquinolinyl, naphthidyl, acridineyl, and phenanthrolinyl. group), benzofuranyl, benzothiopheneyl, oxazolyl, indolyl, carbazoleyl, benzooxazolyl, thiazolyl, benzothiazolyl, quinoxolinyl, benzimidazolyl, dibenzofuranyl, dibenzothiopheneyl, carbonyl and other heterocyclic groups with 5 to 20 ring atoms; unsubstituted amino groups with 1 to 18 carbon atoms, such as monosubstituted amino groups (-NH2), alkylamino groups (e.g., methylamino), acetamino groups, aromatic amino groups (e.g., phenylamino), or disubstituted amino groups with 1 to 18 carbon atoms, such as diethylamino, diphenylamino, acetylphenylamino; unsubstituted thio groups (thiol groups: -SH); substituted thio groups with 1 to 18 carbon atoms, such as methylthio, ethylthio, propylthio, phenylthio, biphenylthio; etc. (In this specification, these substituents are referred to as "substituent group A").These "substituents" can be one or more, and when multiple are included, they can be the same or different from each other. Furthermore, the hydrogen atoms of each substituent constituting substituent group A can be further replaced by substituents selected from substituent group A.

[0033] In one aspect of the invention, R in general formula (1) 1 The substituents are hydrogen atoms, halogen atoms (e.g., chlorine atoms), hydroxyl groups, straight-chain or branched alkyl groups with 1 to 20 carbon atoms that may have substituents, straight-chain or branched alkoxy groups with 1 to 20 carbon atoms that may have substituents, aryloxy groups with 6 to 30 carbon atoms that may have substituents, amino groups with 0 to 60 carbon atoms that may have substituents (e.g., alkyl or aryl), thiols, alkylthiols with 1 to 20 carbon atoms that may have substituents, monovalent aromatic hydrocarbon groups with 6 to 30 carbon atoms that may have substituents, or monovalent heterocyclic groups with 5 to 30 ring-forming atoms that may have substituents (preferably monovalent aromatic heterocyclic groups with 5 to 30 ring-forming atoms that may have substituents bonded by nitrogen atoms, or monovalent aliphatic heterocyclic groups with 5 to 30 ring-forming atoms that may have substituents bonded by nitrogen atoms). In one aspect of the invention, R in general formula (1) 1 It is a halogen atom (e.g., a chlorine atom), an amino group with 0 to 60 carbon atoms that may have substituents, or a monovalent aromatic hydrocarbon group with 6 to 30 carbon atoms that may have substituents. In one aspect of the invention, R in general formula (1) 1 It can be a halogen atom (e.g., a chlorine atom), a heterocyclic group with 5 to 30 monovalent rings that may have substituents, or an aromatic hydrocarbon group with 6 to 30 monovalent carbon atoms that may have substituents.

[0034] In general formula (1), R 2 ~R 29 Represented independently hydrogen atom, Alkyl groups, which may have 1 to 20 carbon atoms and be straight-chain or branched, may have substituents. Alkenes with 2 to 20 carbon atoms that can have substituents are either straight-chain or branched. Cycloalkyl groups having 3 to 12 carbon atoms may have substituents. Alkoxy groups with 1 to 20 carbon atoms that may have substituents, straight-chain or branched alkoxy groups, amino groups with 0 to 20 carbon atoms that may have substituents, or... It can have a thio group with 0 to 20 carbon atoms as a substituent.

[0035] In general formula (1), as R 2 ~R 29The "linear or branched alkyl group having 1 to 20 carbon atoms" in the phrase "linear or branched alkyl group having 1 to 20 carbon atoms that may have substituents" can be exemplified by R in general formula (1). 1 The same alkyl group as "a straight-chain or branched alkyl group that may have 1 to 20 carbon atoms and may have substituents".

[0036] In general formula (1), as R 2 ~R 29 The "linear or branched alkenyl group with 2 to 20 carbon atoms" in the term "linear or branched alkenyl group with 2 to 20 carbon atoms that may have substituents" can be exemplified by the group represented by R in general formula (1). 1 The alkenyl group is the same as the "linear or branched alkenyl group that may have 2 to 20 carbon atoms with substituents".

[0037] In general formula (1), as R 2 ~R 29 The phrase "cycloalkyl group with 3 to 12 carbon atoms that may have substituents" specifically includes cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl, cyclododecyl, 4-methylcyclohexyl, 4-ethylcyclohexyl, etc. The number of carbon atoms in the cycloalkyl group can also be selected in the range of 3 to 10.

[0038] In general formula (1), as R 2 ~R 29 The phrase "a straight-chain or branched alkoxy group having 1 to 20 carbon atoms" in the general formula (1) can be exemplified by R. 1 The same alkoxy group is referred to as "a straight-chain or branched alkoxy group that may have 1 to 20 carbon atoms with substituents".

[0039] In general formula (1), as R 2 ~R 29 The "amino group with 0 to 20 carbon atoms" in the phrase "amino group with 0 to 20 carbon atoms that may have substituents" specifically refers to amino groups derived from R in general formula (1). 1 The amino group that is the same as the amino group with 0 to 20 carbon atoms in the phrase "amino group with 0 to 60 carbon atoms that may have substituents".

[0040] In general formula (1), as R 2 ~R 29 The "thiogroup with 1 to 20 carbon atoms" in the phrase "thiogroup with 1 to 20 carbon atoms that may have substituents" can specifically be exemplified by R in general formula (1). 1It refers to "a thio group that may have 1 to 20 carbon atoms and may have substituents".

[0041] In general formula (1), as R 2 ~R 29 The "substituent" in the following expressions, namely "a straight-chain or branched alkyl group having 1 to 20 carbon atoms that may have substituents", "a straight-chain or branched alkenyl group having 2 to 20 carbon atoms that may have substituents", "a cycloalkyl group having 3 to 12 carbon atoms that may have substituents", "a straight-chain or branched alkoxy group having 1 to 20 carbon atoms that may have substituents", "an amino group having 0 to 20 carbon atoms that may have substituents", or "a thio group having 0 to 20 carbon atoms that may have substituents", can also be exemplified by R in general formula (1). 1 The "substituent" in phrases such as "a straight-chain or branched alkyl group having 1 to 20 carbon atoms that may have substituents" refers to the same substituent.

[0042] In general formula (1), R 10 and R 11 R 24 and R 25 They can bond together to form a ring. For example, R 10 and R 11 R 24 and R 25 It can be a single bond, a bond formed through oxygen atoms, sulfur atoms, selenium atoms, or a ring formed through bonds between nitrogen atoms. In one aspect of the invention, R 10 and R 11 R 24 and R 25 At least one group in the matrix is ​​bonded to each other by a single bond, for example, it can be R 10 and R 11 They are bonded together by single bonds, and R 24 and R 25 They are bonded together by single bonds. In a preferred embodiment of the invention, R 10 and R 11 R 24 and R 25 None of them bonded together to form a loop. R 10 and R 11 R 24 and R 25 Compounds that are not bonded to each other to form rings are preferred over compounds that are bonded to each other to form rings in terms of higher solubility relative to commonly used solvents.

[0043] In general formula (1), R 2 ~R 29 At least one of them (preferably R) 6 ~R 15 R20 ~R 29 At least one of them, more preferably R 7 ~R 9 R 12 ~R 14 R 21 ~R 23 R 26 ~R 28 At least one of them) is preferred to be R 2 ~R 29 Possible substituents. R 2 ~R 29 The number of substituents is preferably in the range of 1 to 12, for example, in the range of 1 to 8, or in the range of 4 to 8. When there are two or more substituents, these substituents may be the same or different. It is preferred that they are the same. In this invention, the substituents are selected from R... 8 R 13 R 22 and R 27 One or more of these are preferably substituents; for example, all of them can be substituents. In one aspect of the invention, R 2 ~R 29 The substituents used are linear or branched alkoxy groups with 1 to 20 carbon atoms, linear or branched alkylthio groups with 1 to 20 carbon atoms, or amino groups (preferably disubstituted amino groups) with 0 to 60 carbon atoms. For example, R 2 ~R 29 The substituents used are straight-chain or branched alkoxy groups having 1 to 20 carbon atoms. In one embodiment of the invention, R 2 ~R 5 R 16 ~R 19 R is a hydrogen atom. In one embodiment of the invention, R 6 R 10 R 11 R 15 R 20 R 24 R 25 R 29 It is a hydrogen atom.

[0044] In general formula (1), one triaryl amino group is bonded at any one of the 1-4 positions of the carbazole, and another triaryl amino group is bonded at any one of the 5-8 positions of the carbazole. For example, one triaryl amino group is bonded at the 2 or 3 position of the carbazole, and another triaryl amino group is bonded at the 6 or 7 position of the carbazole. The bonding positions of the two carbazoles present in general formula (1) are preferably the same. In this invention, the compound represented by general formula (1) is preferably a compound represented by general formula (2) below, in which the triaryl amino group is substituted at the 3 and 6 positions of the carbazole, or a compound represented by general formula (3) below, in which the triaryl amino group is substituted at the 2 and 7 positions of the carbazole. R of general formula (2) and general formula (3) 2 ~R 29 The meaning of R in the general formula (1) is the same as that of R. 2 ~R 29 The meanings are the same.

[0045] [Chemical Formula 2]

[0046] [Chemical Formula 3]

[0047] As a group of compounds represented by general formula (1), it is possible to show R 1 Group 1 comprises compounds that can form monovalent heterocyclic groups with 5 to 30 atoms that have substituents. Group 1 includes: R 1 The group 1a comprises compounds of 5–30 monovalent aromatic heterocyclic groups bonded by carbon atoms that can have substituents forming rings; R 1 The group 1b consists of compounds that can form 5 to 30 diarylamino groups (where two aryl groups are linked together to form a cyclic structure) and have substituents; R 1 Compounds belonging to group 1c are monovalent aromatic heterocyclic groups (excluding compounds belonging to group 1b) that can have 5 to 30 ring-forming atoms bonded by nitrogen atoms and may have substituents; R 1 The group 1d consists of compounds that can form monovalent aliphatic heterocyclic groups with 5 to 30 substituents bonded by carbon atoms. 1 Group 1e comprises compounds having a 5-30-aliphatic heterocyclic group with a nitrogen atom bonded together, which may have a substituent ring. For example, the heterocyclic group in each of groups 1a-1e has a substituent. For example, the heterocyclic group in each of groups 1a-1e is unsubstituted. Each of groups 1a-1e can further satisfy at least one of the following additional conditions. One of the additional conditions is R 2 ~R 29 4 to 8 of them are R 2 ~R 29Substituents that can be used. One of the additional conditions is R. 8 R 13 R 22 and R 27 At least one (e.g., all) of them are R 2 ~R 29 Substituents that can be used. One of the additional conditions is R. 2 ~R 29 At least one of them is a substituent and R 2 ~R 29 The substituents used are straight-chain or branched alkoxy groups with 1 to 20 carbon atoms. One of the additional conditions is R. 2 ~R 29 At least one of them is a substituent and R 2 ~R 29 The substituents used are linear or branched alkylthio groups with 1 to 20 carbon atoms. One of the additional conditions is R. 2 ~R 29 At least one of them is a substituent and R 2 ~R 29 The substituents used are disubstituted amino groups with 2 to 60 carbon atoms. One of the additional conditions is that the compound has a structure represented by the above general formula (2). Another additional condition is that the compound has a structure represented by the above general formula (3).

[0048] As a group of compounds represented by general formula (1), it is possible to show R 1 Group 2 comprises compounds consisting of monovalent aromatic hydrocarbon groups with 6 to 30 carbon atoms that can have substituents. Group 2 includes R... 1 Compounds of unsubstituted phenyl groups 2a and R 1 Compounds belonging to the substituted phenyl group 2b, R 1 Compounds consisting of unsubstituted condensed aromatic hydrocarbon groups, group 2c, R 1 Compounds in group 2d are condensed aromatic hydrocarbon groups having substituents. For example, the substituents in compounds 2b and 2d are selected from substituent group A above. For example, the substituents in compounds 2b and 2d are alkyl or aryl. Compounds 2a to 2d can further satisfy at least one additional condition described in the description of compound group 1.

[0049] As a group of compounds represented by general formula (1), it is possible to show R 1 Compounds in group 3 are amino groups with 0 to 60 carbon atoms having substituents. Compound group 3 includes R... 1 Compounds consisting of unsubstituted amino groups 3a and R 1 Compounds belonging to the group 3b and R with monosubstituted amino groups 1The group of compounds 3c and R are diarylamino compounds that can have substituents. 1 Compounds in group 3d are dialkylamino compounds that may have substituents. For example, the substituents in compounds 3b to 3d are selected from substituent group A above. For example, the substituents in compounds 3b to 3d are alkyl or aryl. Compounds 3a to 3d can each further satisfy at least one additional condition described in the description of compound group 1.

[0050] As a group of compounds represented by general formula (1), it is possible to show R 1 Compounds in group 4 are halogen atoms. Compound group 4 contains R. 1 Compounds with fluorine atoms in groups 4a and R 1 Compounds with chlorine atoms in groups 4b and R 1 Compounds with bromine atoms in the groups 4c and R 1 Compounds of group 4d are iodine atoms. Compounds 4a to 4d can each further satisfy at least one additional condition described in the description of compound group 1.

[0051] As a group of compounds represented by general formula (1), it is possible to show R 1 The group 5 consists of straight-chain or branched alkyl compounds with 1 to 20 carbon atoms that may have substituents. As a group of compounds represented by general formula (1), it is possible to show R 1 The group 6 consists of straight-chain or branched alkenyl compounds that may have 2 to 20 carbon atoms and may have substituents. As a group of compounds represented by general formula (1), it is possible to show R 1 The group 7 consists of straight-chain or branched alkoxy groups that may have 1 to 20 carbon atoms and may have substituents. As a group of compounds represented by general formula (1), it is possible to show R 1 It is a group 8 of compounds that may have aryloxy groups with 6 to 30 carbon atoms that can have substituents. As a group of compounds represented by general formula (1), it is possible to show R 1 It is a group 9 of compounds that may have thio groups with 0 to 20 carbon atoms that can have substituents. As a group of compounds represented by general formula (1), it is possible to show R 1 Compounds consisting of hydrogen atoms belong to group 10. As a group of compounds represented by general formula (1), it is possible to show R 1 Compounds with hydroxyl groups belong to group 11. Compounds 5 through 11 can each further satisfy at least one additional condition described in the description of compound group 1.

[0052] The following are specific examples of compounds represented by the general formula (1) of the present invention; however, the compounds represented by the general formula (1) that can be used in the present invention should not be interpreted as limiting by these specific examples. Furthermore, the following example compounds omit some hydrogen atoms, carbon atoms, etc., and show one example of possible isomers, but include all other isomers. Furthermore, mixtures of two or more isomers may also be included.

[0053] [Chemical Formula 4]

[0054] [Chemical Formula 5]

[0055] [Chemical Formula 6]

[0056] [Chemical Formula 7]

[0057] [Chemical Formula 8]

[0058] [Chemical Formula 9]

[0059] [Chemical Formula 10]

[0060] The compounds of the present invention represented by general formula (1) can be synthesized by known methods. Among the compounds represented by general formula (1), the compounds represented by general formula (2) and the compounds represented by general formula (3) can be synthesized by, for example, the methods described below.

[0061] The compound of general formula (2) can be synthesized by nucleophilic substitution reaction of cyanuric chloride or 2,4-dichloro-1,3,5-triazine derivatives with 3,6-triarylamino-substituted carbazole represented by the following general formula (4).

[0062] [Chemical Formula 11]

[0063] R in the above general formula (4) 2 ~R 29 The meaning of R in the general formula (1) is the same as that of R. 2 ~R 29 The meanings are the same.

[0064] The compound of general formula (3) can be synthesized by nucleophilic substitution reaction of cyanuric chloride or a 2,4-dichloro-1,3,5-triazine derivative with a 2,7-triarylamino-substituted carbazole represented by the following general formula (5).

[0065] [Chemical Formula 12]

[0066] R in the above general formula (5) 2 ~R 29 The meaning of R in the general formula (1) is the same as that of R. 2 ~R 29 The meanings are the same.

[0067] As a purification method for compounds represented by the general formula (1) of the present invention, purification can be performed by column chromatography, adsorption purification using silica gel, activated carbon, activated clay, etc., or recrystallization or crystallization using solvents. Alternatively, these methods can be used simultaneously to obtain compounds with improved purity. Furthermore, the identification of these compounds can be performed by nuclear magnetic resonance (NMR) analysis.

[0068] The preferred embodiment of the photoelectric conversion element of the present invention will be described below.

[0069] <Photoelectric Conversion Components> Next, the photoelectric conversion element of the present invention will be described. The photoelectric conversion element of the present invention is characterized by having a hole transport layer comprising a compound represented by general formula (1). For a description of the compound represented by general formula (1), please refer to the description in the section on <compound represented by general formula (1)> above. The compound represented by general formula (1) has excellent hole transport and electron blocking properties, and therefore can be effectively used as a material for the hole transport layer of the photoelectric conversion element.

[0070] The preferred embodiment of the photoelectric conversion element will be described below, but the embodiment of the photoelectric conversion element of the present invention is not to be limited by the embodiment shown below. In one aspect of the invention, such as Figure 1 As shown, the photoelectric conversion element sequentially 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, wherein the hole transport layer 4 comprises a compound represented by general formula (1). In one aspect of the present invention, the photoelectric conversion element sequentially comprises a conductive support, a hole transport layer, a photoelectric conversion layer, an electron transport layer, and a counter electrode, wherein the hole transport layer comprises a compound represented by general formula (1). Here, the photoelectric conversion layer may, for example, comprise a perovskite-type compound. Furthermore, the photoelectric conversion element may, for example, be a photoelectric conversion element for a solar cell. The following is based on Figure 1 Taking the photoelectric conversion element shown as an example, the components and layers of the photoelectric conversion element will be explained.

[0071] [Conductive support] exist Figure 1 In the photoelectric conversion element shown, the conductive support 1 functions as a cathode that extracts electrons transmitted from the photoelectric conversion layer 3 via the electron transport layer 2. In one embodiment of the invention, the conductive support 1 is a transparent conductive support that transmits light for photoelectric conversion, such as a conductive substrate on which a film of conductive material is formed. Specific examples of conductive materials used for conductive supports include conductive transparent oxide semiconductors such as tin-doped indium oxide (ITO), zinc-doped indium oxide (IZO), tungsten-doped indium oxide (IWO), zinc and aluminum oxide (AZO), fluorine-doped tin oxide (FTO), indium oxide (In2O3), and indium-tin composite oxides. Tin-doped indium oxide (ITO) and fluorine-doped tin oxide (FTO) are preferred.

[0072] [Electron transport layer] The electron transport layer 2 is a layer containing a material (electron transport material) that functions to transport electrons. It is disposed between the conductive support 1 and the photoelectric conversion layer 3, and has the function of transporting electrons generated in the photoelectric conversion layer 3 to the conductive support 1. This improves the efficiency of electron movement from the photoelectric conversion layer to the conductive support. Furthermore, in addition to this function, the electron transport layer may also have the function of suppressing hole injection from the conductive support. The electron transport layer 2 can be formed adjacent to the conductive support 1, or other layers can be sandwiched between the conductive support 1 and the electron transport layer 2.

[0073] Specific examples of semiconductor materials used in 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 monomeric semiconductors such as silicon and germanium. These semiconductor materials can be used individually or in combination of two or more. Preferred examples of semiconductor materials used in electron transport layers include materials composed of one or more of tin oxide, titanium oxide, and zinc oxide.

[0074] As a material for forming the electron transport layer, a slurry (semiconductor slurry) containing microparticles of the aforementioned semiconductor material can be cited as an example. The semiconductor slurry can be a commercially available product or a prepared product made by dispersing fine powders of the aforementioned semiconductor material in a solvent. Specific examples of solvents used in preparing the semiconductor slurry include water; alcohol-based solvents such as methanol, ethanol, and isopropanol; 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, but are not limited to these. These solvents can be used individually or as a mixture of two or more types of solvents.

[0075] As a method for dispersing semiconductor micropowders in a solvent, one example is to pulverize the powder using a mortar or other mortar as needed, and then disperse it in a solvent using a disperser such as a ball mill, paint mixer, vertical bead mill, horizontal bead mill, or atritor. When preparing the slurry, to prevent the agglomeration of semiconductor particles, it is preferable to add surfactants, and to increase viscosity, it is preferable to add thickeners such as polyethylene glycol.

[0076] Electron transport layers can be formed using known film-forming methods. Specifically, electron transport layers can be formed using coating methods or vapor-phase processes that employ a coating solution containing semiconductor materials (such as semiconductor pastes or other electron transport layer coating solutions). Examples include wet coating methods such as spin coating, inkjet coating, doctor blade coating, drop casting, brush coating, screen printing, reverse roll coating, gravure coating, casting coating, roller brush coating, spray coating, air knife coating, wire rod coating, pipe doctor coating, dip coating, or curtain coating, where the electron transport layer coating solution is applied to a conductive substrate, followed by firing to remove solvents and additives; and vapor-phase film-forming methods such as sputtering, vapor deposition, electrodeposition, electrocrystallization, and microwave irradiation to form semiconductor films. The preferred method is to apply the coating liquid for the electron transport layer prepared by spin coating, but it is not limited to this method. Furthermore, the spin coating conditions can be appropriately set. The film-forming atmosphere is not particularly limited and can be atmospheric or an inert atmosphere.

[0077] The thickness of the electron transport layer is, for example, 5 nm to 200 nm, preferably 10 nm to 150 nm. Furthermore, for example, from the viewpoint of further improving photoelectric conversion efficiency, when a dense electron transport layer is used, the thickness of the electron transport layer is generally preferably 5 nm to 100 nm, and more preferably 10 nm to 50 nm. In this invention, when a mesoporous metal oxide is used in addition to the dense layer, its thickness is generally preferably 20 nm to 200 nm, and more preferably 50 nm to 150 nm.

[0078] [Photoelectric conversion layer] Photoelectric conversion layer 3 is a layer used to convert light energy into electricity, more specifically, a layer that generates holes and electrons by creating charge separation states through light energy. Figure 1 In the photoelectric conversion element shown, the photoelectric conversion layer 3 is formed on the side of the electron transport layer 2 opposite to the conductive support 1.

[0079] As an example of a photoelectric conversion layer, a layer formed of perovskite material (perovskite layer) can be cited. Here, "perovskite material" refers to a material having a perovskite-type structure represented by the general formula ABX3. In this formula, A represents a monovalent organic cation or a monovalent metal cation, B represents a divalent metal cation, and X represents a halide ion. As a monovalent cation represented by A, K0 can be cited as an example. + 、Rb + Cs + CH3NH3 + (Hereinafter, MA: methylammonium), NH=CHNH2 + (FA: formamidinium) CH3CH2NH3 + (Hereinafter, EA: ethylammonium). Pb is an example of a divalent metal cation represented by B. 2+ Sn 2+ As a halide ion represented by X, I0 can be cited as an example. - ,Br - . Specific examples of perovskite materials include MAPbI3, FAPbI3, EAPbI3, CsPbI3, MASnI3, FASnI3, EASnI3, MAPbBr3, FAPbBr3, EAPbBr3, MASnBr3, FASnBr3, and EASnBr3. Furthermore, mixed cationic and mixed anionic perovskite materials such as (FAMA)Pb(IBr)3, K(FAMA)Pb(IBr)3, Rb(FAMA)Pb(IBr)3, and Cs(FAMA)Pb(IBr)3 can also be cited. The photoelectric conversion layer may contain only one type of these perovskite materials, or it may contain two or more types.

[0080] Furthermore, the photoelectric conversion layer can be composed solely of perovskite material, or it can contain both perovskite material and other materials. Examples of other materials include light absorbers.

[0081] The perovskite layer can be formed by coating a solution of halide AX and metal halide BX2 (perovskite precursor solution) to form a precursor coating film and then drying the precursor coating film. Specific examples of A, B, and X can be found in the description of the ions constituting ABX3 described above. For example, specific examples of halide AX include methylammonium halide, formamidinium halide, and cesium halide; specific examples of metal halide BX2 include lead halide and tin halide.

[0082] From the viewpoint of precursor solubility, solvents for perovskite precursor solutions can include N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), γ-butyrolactone, etc., but are not limited to these. Furthermore, one of these solvents can be used alone, or two or more can be used in combination. A preferred example of a solvent is a mixture of N,N-dimethylformamide and dimethyl sulfoxide. Moreover, the solvent preferably uses a dehydrating solvent with a water content of 10 ppm or less. Dehydration of the solvent can be performed using molecular sieves or the like.

[0083] The coating process of the perovskite precursor solution is preferably performed under a dry atmosphere, and more preferably under a dry inert gas atmosphere such as a glove box. This prevents moisture from contaminating the perovskite layer, enabling the manufacture of high-efficiency perovskite solar cells with good reproducibility. For the coating method, please refer to the description of the coating method for the electron transport layer coating solution in the [Electron Transport Layer] section above.

[0084] The perovskite layer is formed by drying the precursor coating thus formed. The drying of the precursor coating can be natural drying or drying by heating using a hot plate or the like. From the viewpoint of generating perovskite material from a precursor, the temperature for heating the precursor coating using a hot plate or the like is preferably 50–200°C, more preferably 70–150°C. Furthermore, the heating time is preferably about 10–90 minutes, more preferably about 10–60 minutes.

[0085] The thickness of the photoelectric conversion layer (perovskite layer) is preferably 50–1000 nm, more preferably 300–700 nm. This suppresses performance degradation caused by defects and peeling of the photoelectric conversion layer, prevents the element resistance from becoming too high, and enables the photoelectric conversion layer to have sufficient light absorption.

[0086] Hole transport layer exist Figure 1In the photoelectric conversion element shown, the hole transport layer 4 is a layer containing a material (hole transport material) that has the function of transporting holes, and is disposed between the photoelectric conversion layer 3 and the counter electrode 5. It has the function of transporting holes generated in the photoelectric conversion layer 3 to the counter electrode 5. This improves the efficiency of hole movement from the photoelectric conversion layer to the electrode. Furthermore, in addition to this function, the hole transport layer can also suppress electron injection from the counter electrode.

[0087] In the photoelectric conversion element of the present invention, the hole transport layer contains a compound represented by general formula (1) as a hole transport material. The compound represented by general formula (1) contained in the hole transport layer can be one or more compounds selected from the group of compounds represented by general formula (1). By containing a compound represented by general formula (1) in the hole transport layer, a layer with high hole transport capability and excellent function of blocking electron movement from the counter electrode can be formed. Furthermore, in addition to containing a compound represented by general formula (1), the hole transport layer may also contain a hole transport material that does not belong to the group of compounds represented by general formula (1) (hereinafter referred to as "second hole transport material") and additives.

[0088] The second hole transport material can be either inorganic or organic. Specific examples of inorganic hole transport materials 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. Examples of organic hole transport materials include polythiophene derivatives such as poly-3-hexylthiophene (P3HT) and polyvinyldioxythiophene (PEDOT); spirodihydrogen derivatives such as 2,2',7,7'-tetra-(N,N-di-p-methoxyaniline)-9,9'-spirodihydrogen (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. These second hole transport materials can be mixed in the hole transport layer, or a hole transport layer containing the second hole transport material can be stacked on top of a hole transport layer containing a compound represented by general formula (1). In one aspect of the invention, the hole transport layer is a single layer and contains only the compound represented by general formula (1) as the hole transport material.

[0089] For the method of forming the hole transport layer, please refer to the description of the method of forming the electron transport layer described above. Furthermore, the solvent for the coating liquid used in the hole transport layer can also be one of the following solvents. That is, the solvents used in the coating solution for the hole transport layer can include aromatic organic solvents such as benzene, toluene, xylene, mesitylene, tetrahydronaphthalene (1,2,3,4-tetrahydronaphthalene), monochlorobenzene (chlorobenzene), o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, and nitrobenzene; halogenated alkyl organic solvents such as dichloromethane, chloroform, 1,2-dichloroethane, and 1,1,2-trichloroethane; nitrile solvents such as benzonitrile and acetonitrile; ether solvents such as tetrahydrofuran, dioxane, 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, but are not limited to these. These solvents can be used alone or in combination of two or more. Among them, aromatic organic solvents and halogenated alkyl organic solvents are preferred for the coating liquid used to form the hole transport layer.

[0090] The atmosphere used during the formation of the hole transport layer is preferably a dry atmosphere. Furthermore, it is preferable to use a solvent in the coating solution that has been dehydrated to a water content of 10 ppm or less. By preventing moisture contamination, high-efficiency perovskite solar cells can be manufactured with good reproducibility. From the perspective of further improving photoelectric conversion efficiency, the thickness of the hole transport layer is preferably 5nm to 500nm, and more preferably 10nm to 250nm.

[0091] additive Examples of additives that can be added to the hole transport layer include oxidants (dopersants) and basic compounds (basic additives). By adding these additives to the hole transport layer, the carrier concentration of the hole transport layer can be increased, thereby improving the photoelectric conversion efficiency of the photoelectric conversion device.

[0092] Specific examples of dopants include lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), silver bis(trifluoromethanesulfonyl)imide, zinc (II) bis(trifluoromethanesulfonyl)imide, copper (II) bis(trifluoromethanesulfonyl)imide, magnesium (II) bis(trifluoromethanesulfonyl)imide, calcium (II) bis(trifluoromethanesulfonyl)imide, tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt (III)tris[bis(trifluoromethanesulfonyl)imide](FK209), NOSbF6, SbCl5, SbF5, etc., among which lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) is preferred.

[0093] The concentration of dopant in the hole transport layer is preferably 2.0 equivalents or less, more preferably 0.5 equivalents or less, relative to 1 equivalent of the hole transport material. This is because the presence of additives in the hole transport layer improves the photoelectric conversion efficiency of the photoelectric conversion element. On the other hand, if the concentration of dopant is too high, the durability of the photoelectric conversion element may be reduced. Specific examples of basic additives include 4-tert-butylpyridine (tBP), 2-methylpyridine, and 2,6-dimethylpyridine, among which 4-tert-butylpyridine is preferred. Furthermore, basic additives can be used simultaneously with dopants. The concentration of the alkaline additive in the hole transport layer is preferably 5 equivalents or less, more preferably 3.5 equivalents or less, relative to 1 equivalent of the hole transport material.

[0094] [Counter electrode] The counter electrode 5 is an electrode formed on the side of the hole transport layer 4 opposite to the photoelectric conversion layer 3, with the electron transport layer 2, photoelectric conversion layer 3, and hole transport layer 4 sandwiched between them, and is disposed opposite to the conductive support 1. The counter electrode functions as the anode for extracting holes transported from the photoelectric conversion layer via the hole transport layer. The counter electrode 5 can be disposed adjacent to the hole transport layer 4, or an electron blocking layer made of organic material or inorganic compound semiconductor can be sandwiched between the hole transport layer 4 and the counter electrode 5.

[0095] Specifically, materials used to construct the counter electrode include metals such as platinum, titanium, stainless steel, aluminum, gold, silver, nickel, magnesium, chromium, cobalt, and copper, or their alloys. Among these, gold, silver, or silver alloys are preferred due to their high conductivity even in the thin film. For silver alloys, considering their resistance to sulfidation or chlorination and resulting in high film stability, examples include silver-gold alloys, silver-copper alloys, silver-palladium alloys, silver, copper, and palladium alloys, and silver-platinum alloys. Furthermore, the counter electrode is preferably made of a material that can be formed in a vapor-phase process such as vapor deposition. When a metal electrode is used as the counter electrode, in order to obtain good conductivity, its film thickness is preferably 10 nm or more, and more preferably 50 nm or more.

[0096] exist Figure 1 In the photoelectric conversion element shown, the conductive support 1 is the cathode, and the counter electrode 5 is the anode. Sunlight or other light (the light used for photoelectric conversion) preferably irradiates from the conductive support side. Upon irradiation by sunlight or other light, the photoelectric conversion layer absorbs the light and becomes excited, generating electrons and holes. Current flows through the movement of electrons via the electron transport layer towards the conductive support, and holes move via the hole transport layer towards the counter electrode, thus functioning as the photoelectric conversion element. Furthermore, the photoelectric conversion element of the present invention may sequentially include a conductive support, a hole transport layer, a photoelectric conversion layer, an electron transport layer, and a counter electrode. In this case, the conductive support functions as the anode, and the counter electrode functions as the cathode. Electrons generated in the photoelectric conversion layer move to the counter electrode via the electron transport layer, and holes generated in the photoelectric conversion layer move to the conductive support via the hole transport layer. Thus, current can be extracted to the outside. For a description and specific examples of the materials used in this method for each part and layer, please refer to the above description. Figure 1 The corresponding description of the photoelectric conversion element shown.

[0097] When evaluating the performance (characteristics) of the photoelectric conversion element of the present invention, short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency are measured. Short-circuit current density refers to the current flowing between the two terminals per 1 cm² when the output terminals are short-circuited. 2 The open-circuit voltage refers to the voltage between the two terminals when the output terminals are open-circuited. Furthermore, the fill factor is the value obtained by dividing the maximum output (the product of current and voltage) by the product of the short-circuit current density and the open-circuit voltage, and is mainly affected by internal resistance. The photoelectric conversion efficiency is calculated as follows: (The maximum output (W) is divided by the fill factor per 1cm²). 2 The value obtained by multiplying the light intensity (W) by 100 is expressed as a percentage value. If the initial photoelectric conversion efficiency of the photoelectric conversion element under the element structure of the present invention is 10% or higher, it can be judged as having good photoelectric conversion efficiency.

[0098] The photoelectric conversion element of the present invention can be applied to solar cells, various photosensors, etc. The solar cell to which the photoelectric conversion element of the present invention is applicable is preferably a perovskite solar cell. The solar cell is obtained by modularizing a required number of photoelectric conversion elements containing a compound represented by general formula (1) in the hole transport layer as a battery cell and providing prescribed electrical wiring. Example

[0099] The features of the present invention will be specifically described below by way of examples. The materials, processing methods, processing order, etc., shown below can be appropriately modified without departing from the spirit of the present invention. Therefore, the present invention is not limited to the following examples. Furthermore, through… 1 The compounds obtained in the synthesis examples were identified using H-NMR (JEOL Ltd. nuclear magnetic resonance apparatus, type JNM-ECZ400S / L1).

[0100] [Synthetic Example 1] Synthesis of Compound (A-1) 3,6-bis(4-(bis(4-methoxyphenyl)amino)phenyl)-9H-carbazole (336 mg, manufactured by Tokyo Chemical Industry Co., Ltd.), DMF (10 mL), and sodium hydride (19 mg, 55% purity, manufactured by Kanto Chemical Co., Inc.) were added to a reaction vessel and stirred in an ice bath for 30 minutes. Then, cyanuric chloride (25 mg, manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was stirred at room temperature for 1 hour. After the reaction was complete, water (20 mL) was added, and the precipitated solid was recovered by suction filtration. The filtered crude product was purified by silica gel column chromatography (toluene:ethyl acetate = 20:1) to obtain compound (A-1) as a pale yellow powder (yield: 263 mg, 81%). 1 H-NMR (400MHz, DMSO-d6): δ (ppm) = 8.71 (6H), 8.34 (6H), 7.48 (12H), 7.38 (6H), 6.95 (24H), 6.83 (24H), 3.71 (36H).

[0101] [Synthetic Example 2] Synthesis of Compound (A-2) 2,7-bis(4-(bis(4-methoxyphenyl)amino)phenyl)-9H-carbazole (168 mg, manufactured by Tokyo Chemical Industry Co., Ltd.), DMF (3 mL), and sodium hydride (10 mg, 55% purity, manufactured by Kanto Chemical Co., Inc.) were added to a reaction vessel and stirred in an ice bath for 30 minutes. Then, cyanuric chloride (15 mg, manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was stirred at room temperature for 1 hour. After the reaction was complete, water (20 mL) was added, and the precipitated solid was recovered by suction filtration. The filtered crude product was purified by silica gel column chromatography (toluene:ethyl acetate = 20:1) to obtain compound (A-2) as a pale yellow powder (yield: 74 mg, 47%). 1 H-NMR (400MHz, DMSO-d6): δ (ppm) = 9.15 (6H), 8.13 (6H), 7.58 (6H), 7.13 (12H), 6.84 (48H), 3.72 (36H).

[0102] [Synthetic Example 3] Synthesis of Compound (A-3) 3,6-bis(4-(bis(4-methoxyphenyl)amino)phenyl)-9H-carbazolin (143 mg, manufactured by Tokyo Chemical Industry Co., Ltd.), DMF (3 mL), and sodium hydride (9 mg, 55% purity, manufactured by Kanto Chemical Co., Inc.) were added to a reaction vessel and stirred in an ice bath for 30 minutes. Then, 2,4-dichloro-6-phenyl-1,3,5-triazine (20 mg, manufactured by Tokyo Chemical Industry Co., Ltd.) was added and stirred at room temperature for 30 minutes. After the reaction was complete, water (20 mL) was added, and the precipitated solid was recovered by suction filtration. The filtered crude product was purified by silica gel column chromatography (toluene:ethyl acetate = 6:1) to obtain compound (A-3) as a yellow powder (yield: 104 mg, 69%). 1 H-NMR (400MHz, DMSO-d6): δ (ppm) = 8.82 (4H), 8.58 (2H), 8.46 (4H), 7.68 (3H), 7.63 (4H), 7.55 (8H), 6.95 (16H), 6.84 (16H), 6.78 (8H), 3.69 (24H).

[0103] [Synthetic Example 4] Synthesis of Compound (A-4) 2,7-bis(4-(bis(4-methoxyphenyl)amino)phenyl)-9H-carbazole (143 mg, manufactured by Tokyo Chemical Industry Co., Ltd.), DMF (3 mL), and sodium hydride (10 mg, 55% purity, manufactured by Kanto Chemical Co., Inc.) were added to a reaction vessel and stirred in an ice bath for 30 minutes. Then, 2,4-dichloro-6-phenyl-1,3,5-triazine (20 mg, manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was stirred at room temperature for 1.5 hours. After the reaction was complete, water (20 mL) was added, and the precipitated solid was recovered by suction filtration. The filtered crude product was washed with methanol and ethyl acetate to obtain compound (A-4) as a yellow powder (yield: 96 mg, 64%). 1 H-NMR (400MHz, DMSO-d6): δ (ppm) = 9.15 (4H), 8.61 (2H), 8.05 (4H), 7.65 (1H), 7.57 (4H), 7.49 (2H), 7.34 (8H), 6.93 (16H), 6.85(16H), 6.65(8H), 3.72(24H).

[0104] [Synthetic Example 5] Synthesis of Compound (A-5) 3,6-bis(4-(bis(4-methoxyphenyl)amino)phenyl)-9H-carbazole (600 mg, manufactured by Tokyo Chemical Industry Co., Ltd.), DMF (12 mL), and sodium hydride (34 mg, manufactured by Kanto Chemical Co., Inc.) were added to a reaction vessel and stirred in an ice bath for 30 minutes. After cooling the reaction system to -10°C, cyanuric chloride (23 mg, manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was stirred at -10°C for 2 hours and then at 0°C for 90 minutes. After the reaction was complete, water (50 mL) was added, and the precipitated solid was recovered by suction filtration. The filtered crude product was purified by silica gel column chromatography (toluene:ethyl acetate = 50:1 → 30:1 → 10:1) to obtain compound (A-5) as a yellow powder (yield: 200 mg, 30%). 1 H-NMR (400MHz, DMSO-d6): δ (ppm) = 8.53 (4H), 8.22 (4H), 7.46 (12H), 6.77-6.93 (40H), 3.72 (24H).

[0105] [Synthetic Example 6] Synthesis of Compound (A-16) 3,6-bis(4-(bis(4-methoxyphenyl)amino)phenyl)-9H-carbazolin (280 mg, manufactured by Tokyo Chemical Industry Co., Ltd.), DMF (5 mL), and sodium hydride (16 mg, manufactured by Kanto Chemical Co., Inc.) were added to a reaction vessel and stirred in an ice bath for 30 minutes. Then, 2,4-dichloro-6-morpholino-1,3,5-triazine (40 mg, manufactured by Tokyo Chemical Industry Co., Ltd.) was added and stirred at room temperature for 90 minutes. After the reaction was complete, water (50 mL) was added, and the precipitated solid was recovered by suction filtration. The filtered crude product was purified by silica gel column chromatography (toluene:ethyl acetate = 10:1) to obtain compound (A-16) as a pale yellow powder (yield: 99 mg, 33%). 1H-NMR (400MHz, DMSO-d6): δ (ppm) = 8.65 (4H), 8.47 (4H), 7.53 (12H), 6.94 (16H), 6.84 (16H), 6.76 (8H), 3.99 (4H), 3.81-3.87 (4H), 3.70 (24H).

[0106] [Example 1] Fabrication of a photoelectric conversion element using compound (A-1) The glass with an ITO film (conductive support 1, manufactured by GEOMATEC Co., Ltd.) was ultrasonically cleaned with isopropanol and then subjected to UV ozone treatment. Subsequently, under a dry atmosphere with a relative humidity of less than 10%, the electron transport layer 2, photoelectric conversion layer 3, and hole transport layer 4 were formed by coating. A tin oxide dispersion (coating solution for the electron transport layer) obtained by spin-coating a tin oxide colloidal solution (tin oxide (IV), 15% H2O colloidal dispersion (Alfa Aesar)) and purified water at a 1:1 (volume ratio) was spin-coated onto an ITO film. Then, a tin oxide layer (electron transport layer 2) with a thickness of approximately 20 nm was formed by heating on a hot plate at 150°C for 30 minutes.

[0107] A perovskite precursor solution was prepared by dissolving formamidinium 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.) in a mixed solvent of dimethylformamide:dimethyl sulfoxide = 4:1 (volume ratio). A dimethyl sulfoxide solution of cesium iodide (1.5M, manufactured by Tokyo Chemical Industry Co., Ltd.) was further added. Here, the cesium iodide solution was added in an amount of 5% by composition. Under a dry atmosphere with a relative humidity below 10% RH, the prepared perovskite precursor solution was dropwise onto a tin oxide layer while chlorobenzene (0.35 mL) was added dropwise and spin-coated, thereby forming a perovskite precursor coating. Then, it was heated at 100°C for 1 hour on a hot plate, thus forming a Cs(MAFA)Pb(IBr)3 perovskite layer (photoelectric conversion layer 3) with a thickness of approximately 500 nm.

[0108] As a dopant, lithium bis(trifluoromethanesulfonyl)imide was dissolved in acetonitrile at a concentration of 1.8 M to prepare a dopant solution. Furthermore, compound (A-1), obtained in Synthesis Example 1 as a hole transport material, was dissolved in chlorobenzene at a concentration of 30 mM at 70 °C. 4-tert-butylpyridine was added to make the amount 3.3 equivalents relative to compound (A-1). Then, the dopant solution was added to make the amount of lithium bis(trifluoromethanesulfonyl)imide relative to compound (A-1) 0.5 equivalents, thereby preparing a coating solution for a hole transport layer. A hole transport layer 4 with a thickness of approximately 200 nm was formed by spin-coating a hole transport layer coating solution onto a Cs(MAFA)Pb(IBr)3 layer (photoelectric conversion layer 3).

[0109] Above the hole transport layer, vacuum evaporation is used at a vacuum degree of 1×10⁻⁶. -4 A gold film of about 80 nm was formed at about Pa, thereby forming a gold electrode (counter electrode 5), and a photoelectric conversion element was fabricated.

[0110] [Example 2] Fabrication of a photoelectric conversion element using compound (A-3) Instead of compound (A-1), compound (A-3) was dissolved in chlorobenzene at a concentration of 50 mM at room temperature and spin-coated. Otherwise, a photoelectric conversion element was fabricated in the same manner as in Example 1.

[0111] [Example 3] Fabrication of a photoelectric conversion element using compound (A-4) Instead of compound (A-1), compound (A-4) was dissolved in chlorobenzene at a concentration of 50 mM at room temperature and spin-coated. Otherwise, a photoelectric conversion element was fabricated in the same manner as in Example 1.

[0112] [Example 4] Fabrication of a photoelectric conversion element using compound (A-5) Instead of compound (A-1), compound (A-5) was dissolved in chlorobenzene at a concentration of 27 mM at room temperature and spin-coated. Otherwise, a photoelectric conversion element was fabricated in the same manner as in Example 1.

[0113] [Example 5] Fabrication of a photoelectric conversion element using compound (A-16) Instead of compound (A-1), compound (A-16) was dissolved in chlorobenzene at a concentration of 26 mM at room temperature and spin-coated. Otherwise, a photoelectric conversion element was fabricated in the same manner as in Example 1.

[0114] [Comparative Example 1] Fabrication of a photoelectric conversion element using comparative compound (B-1) Instead of compound (A-1), Spiro-OMeTAD (manufactured by Sigma-Aldrich), a standard hole transport material represented by the following formula (B-1), was dissolved in chlorobenzene at a concentration of 70 mM at room temperature. Otherwise, the photoelectric conversion element was fabricated in the same manner as in Example 1.

[0115] [Chemical Formula 13]

[0116] [Evaluation of characteristics] For each photoelectric conversion element fabricated in Examples 1-5 and Comparative Example 1, sunlight-like light (AM1.5, 1000W / m²) generated by a white light irradiation device (manufactured by Bunkoukeiki Co., Ltd., OTETO-SUN SH type) was irradiated from the conductive support side of the photoelectric conversion element. 2 The initial photoelectric conversion efficiency was obtained by measuring the current-voltage characteristics using a source meter (KEITHLEY, Model 2400 series). After measuring the current-voltage characteristics, the photoelectric conversion element was sealed in a laminated bag with a zipper (SEISANNIPPONSHA LTD., AL-8) in a glove box under a nitrogen atmosphere. The sealed photoelectric conversion element was then placed in a vacuum desiccator (TOKYO RIKAKIKAI CO.,LTD., VOS-310C) and stored at 85°C for 1,000 hours. The current-voltage characteristics were then measured again under sunlight-like irradiation, thus obtaining the photoelectric conversion efficiency after 1,000 hours of heating. The retention rate (%) calculated using the initial photoelectric conversion efficiency and the photoelectric conversion efficiency after heating for 1,000 hours is shown in Table 1 by the following formula (a-1). [Formula 1]

[0117] [Table 1] Hole transport materials Retention rate [%) Example 1 A-1 94.95 Example 2 A-3 66.19 Example 3 A-4 99.58 Example 4 A-5 66.34 Example 5 A-16 96.91 Comparative Example 1 B-1 34.26

[0118] Furthermore, as shown in Table 1, the photoelectric conversion elements using compounds (A-1), (A-3), (A-4), (A-5), and (A-16) of general formula (1) as hole transport materials exhibit a higher retention rate of photoelectric conversion efficiency after heating for 1,000 hours compared to photoelectric conversion elements using the standard hole transport material (B-1), thus demonstrating excellent heat resistance. Moreover, regarding the photoelectric conversion element using compound (A-2) as the hole transport material, no decrease in photoelectric conversion efficiency was observed after heating for 1,000 hours; it maintained a higher photoelectric conversion efficiency than the photoelectric conversion element using the standard hole transport material and also exhibited excellent heat resistance. Industrial availability

[0119] By using the compound represented by general formula (1) as a hole transport material, and as a photoelectric conversion element with good photoelectric conversion efficiency and excellent heat resistance, solar energy can be efficiently converted into electrical energy, and as a solar cell, it can provide clean energy. Therefore, the present invention has high industrial applicability. Symbol Explanation

[0120] 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), [Chemical Formula 1] In the formula, R 1 Represents hydrogen atom, halogen atom, hydroxyl group, Alkyl groups, which may have 1 to 20 carbon atoms and be straight-chain or branched, may have substituents. Alkenes with 2 to 20 carbon atoms that can have substituents are either straight-chain or branched. Alkoxy groups, which may have 1 to 20 carbon atoms and be straight-chain or branched, can have substituents. Aryloxy groups with 6 to 30 carbon atoms that may have substituents, and amino groups with 0 to 60 carbon atoms that may have substituents. It can have a thio group with 0 to 20 carbon atoms as a substituent. It may be a monovalent aromatic hydrocarbon group with 6 to 30 carbon atoms having a substituent, or Rings with substituents can form monovalent heterocyclic groups with 5 to 30 atoms. R 2 ~R 29 Represented independently hydrogen atom, Alkyl groups, which may have 1 to 20 carbon atoms and be straight-chain or branched, may have substituents. Alkenes with 2 to 20 carbon atoms that can have substituents are either straight-chain or branched. Cycloalkyl groups having 3 to 12 carbon atoms may have substituents. Alkoxy groups, which may have 1 to 20 carbon atoms and be straight-chain or branched, can have substituents. Amino groups with 0 to 20 carbon atoms that may have substituents, or It can have a thio group with 0 to 20 carbon atoms as a substituent. R 10 and R 11 R 24 and R 25 They can bond together to form a ring.

2. The compound according to claim 1, wherein, In the general formula (1), R 1 It can be a halogen atom, an amino group with 0 to 60 carbon atoms that may have substituents, an aromatic hydrocarbon group with 6 to 20 carbon atoms that may have substituents, or a monovalent heterocyclic group with 5 to 30 ring-forming atoms that may have substituents.

3. The compound according to claim 1, wherein, In the general formula (1), R 6 ~R 15 and R 20 ~R 29 At least one of them is a straight-chain or branched alkoxy group having 1 to 20 carbon atoms and may have substituents.

4. The compound according to claim 1, wherein, R 10 and R 11 R 24 and R 25 None of them bonded together to form a ring.

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

6. The hole transport material according to claim 5, used as a hole transport layer in a photoelectric conversion element.

7. A photoelectric conversion element having a hole transport layer comprising the compound of any one of claims 1 to 4.

8. A solar cell that uses the photoelectric conversion element of claim 7.

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