Perovskite solar cell and liquid composition for forming hole layer transport layer

Abstract

Provided are: a perovskite solar cell having a high photoelectric conversion efficiency; a liquid composition that is suitably used in formation of a hole layer transport layer in the perovskite solar cell; and a carbazole compound and a phenethylamine compound that can suitably be blended in this liquid composition.　Provided is the perovskite solar cell that comprises, in order, a first electrode layer, a hole transport layer, a photoelectric conversion layer, an electron transport layer, and a second electrode layer, wherein compounds each having a specific structure are added to a self-assembled monolayer serving as the hole transport layer.

Description

Perovskite solar cell and liquid composition for forming hole transport layer

[0001] The present invention relates to a perovskite solar cell and a liquid composition for forming a hole transport layer.

[0002] The use of solar cells is expanding as an energy source with a low environmental impact. When solar cells are installed in various devices, vehicles, buildings, etc., the available installation area is limited, making the photoelectric conversion efficiency of the solar cell important. Perovskite solar cells, which use organic materials, have been researched as solar cells with high photoelectric conversion efficiency. A basic perovskite solar cell comprises a substrate, a first electrode (anode or cathode), a hole transport layer (hole transport layer or electron transport layer), a photoelectric conversion layer (perovskite layer), an electron transport layer (electron transport layer or hole transport layer), and a first electrode (cathode or anode) stacked in this order. Furthermore, it is known that the photoelectric conversion efficiency can be improved by providing a first buffer layer between the first electrode and the hole transport layer or by providing a second buffer layer between the electron transport layer and the second electrode.

[0003] Furthermore, Patent Document 1 describes a solar cell in which a monomolecular film is formed on the surface of a first electrode laminated on a substrate, a photoelectric conversion layer is directly laminated on the monomolecular film, and an electron transport layer and a transparent electrode are further laminated.

[0004] JP 2010-141165 A

[0005] Patent Document 1 recommends adding a hole transport layer between the monolayer and the photoelectric conversion layer to enable more efficient extraction of charges. The hole transport layer blocks electrons and increases the selectivity of holes that reach the electrode, thereby improving photoelectric conversion efficiency.

[0006] Another known method for improving photoelectric conversion efficiency is passivation of the stacked structure of perovskite solar cells. Passivation is a method for reducing photoelectric conversion loss due to charge recombination by suppressing defects in the photoelectric conversion layer through chemical interactions with anions and cations within and / or on the surface of the photoelectric conversion layer.

[0007] However, conventional passivation methods are often applied after the formation of a perovskite layer. In this case, it is difficult to prevent loss of conversion efficiency due to charge recombination that occurs between the hole transport layer and the perovskite layer in a pin structure. Therefore, there is a need for a method that can more simply prevent charge recombination between the hole transport layer and the perovskite layer while promoting hole transport, thereby increasing photoelectric conversion efficiency.

[0008] An object of the present invention is to provide a perovskite solar cell with high photoelectric conversion efficiency, a liquid composition that is suitably used for forming a hole transport layer in the perovskite solar cell, and a phenethylamine compound and a carbazole compound that can be suitably incorporated into the liquid composition.

[0009] A perovskite solar cell according to one embodiment of the present invention includes a first electrode layer, a hole transport layer, a photoelectric conversion layer, an electron transport layer, and a second electrode layer in this order, wherein the hole transport layer is represented by the following formula (1-1): (HO) ２ P(=O)-(CH ２ ) ｎ１ -X １ -Ph １ -CH ２ CH ２ -NH ２ (1-1) (In formula (1-1), n1 is an integer of 0 to 10, and X １ is a single bond, an oxygen atom, -NR-, or a sulfur atom, and Ph １ is a phenylene group which may have a substituent, and R is a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. ２ P(=O)-(Ph ２ ) ｎ２ -Cbz １ (2-1) (In formula (2-1), Ph ２ is a phenylene group which may be substituted with an alkyl group having from 1 to 6 carbon atoms and / or an alkoxy group having from 1 to 6 carbon atoms, and Cbz １is a 9H-carbazole-9-yl group optionally substituted with one or more substituents selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom, and n2 is an integer of from 2 to 10. ２ P(=O)-Ph ２ -Cbz ２ (2-2) (In formula (2-2), Ph ２ is a phenylene group which may be substituted with an alkyl group having from 1 to 6 carbon atoms and / or an alkoxy group having from 1 to 6 carbon atoms, and Cbz ２ is a 9H-carbazol-9-yl group substituted with one or more substituents selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom; and Cbz ２ The number of substituents of the 9H-carbazole-9-yl group as the group is one.) A self-assembled monolayer II containing one or more carbazole compounds (C2) selected from carbazole compounds (C2-2) represented by the following formula (3-1): (HO) ２ P(=O)-(Ph ３ ) ｎ３ -Cbz ３ (3-1) (In formula (3-1), Ph ３ is a phenylene group which may be substituted with an alkyl group having from 1 to 6 carbon atoms and / or an alkoxy group having from 1 to 6 carbon atoms, and Cbz ３ is a 9H-carbazole-9-yl group optionally substituted with one or more groups selected from the group consisting of alkyl groups having from 1 to 6 carbon atoms and halogen atoms, and n3 is an integer of from 1 to 10; or a self-assembled monolayer III containing a carbazole compound (C3) represented by the following formula (4-1): (HO) ２ P(=O)-R １ -Cbz ４ (4-1) (In formula (4-1), R １ is a divalent organic group, and Cbz ４is a 9H-carbazol-9-yl group which may be substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom. ２ -R ２ -Cbz ４ (4-2) Cbz ４ -R ２ - (S) ｎ４ -R ２ -Cbz ４ (4-3) (In formula (4-2), X ２ is a heteroatom or a heteroatom-containing group, and R ２ is a divalent hydrocarbon group, and X ２ is a heteroatom-containing group, R ２ The divalent hydrocarbon group represented by Cbz is bonded to a heteroatom in the heteroatom-containing group. ４ is Cbz in formula (4-1). ４ In formula (4-3), Cbz ４ is Cbz in formula (4-1). ４ is the same as R ２ is R in formula (4-2). ２ and n4 represents an integer of 2 to 8.) and a self-assembled monolayer IV comprising:

[0010] In the above-described perovskite solar cell, when the hole transport layer is the self-assembled monolayer I, the hole transport layer may contain a carbazole compound (C0).

[0011] In the above-described perovskite solar cell, when the hole transport layer is a self-assembled monolayer I and contains a carbazole compound (C0), the carbazole compound (C0) may be selected from the group consisting of N-(2-phosphonoethyl)carbazole, N-(2-phosphonoethyl)-3,6-dimethoxycarbazole, N-(2-phosphonoethyl)-3,6-dimethylcarbazole, N-(2-phosphonoethyl)-2,7-dimethoxycarbazole, N-(2-phosphonoethyl)-2,7-dimethylcarbazole, N-(3-phosphonopropyl)carbazole, N-(3-phosphonopropyl)-3,6-dimethoxycarbazole, N-(3-phosphonopropyl)-3,6-dimethylcarbazole, N-(3-phosphonopropyl)-2,7-dimethoxycarbazole, N-(3-phosphonopropyl)-2,7-dimethylcarbazole, N-(4-

[0046] The compound may contain one or more selected from the group consisting of N-(4-phosphonobutyl)carbazole, N-(4-phosphonobutyl)-3,6-dimethoxycarbazole, N-(4-phosphonobutyl)-3,6-dimethylcarbazole, N-(4-phosphonobutyl)-2,7-dimethoxycarbazole, N-(4-phosphonobutyl)-2,7-dimethylcarbazole, N-(4-phosphonophenyl)carbazole, N-(4-phosphonophenyl)-3,6-dimethoxycarbazole, N-(4-phosphonophenyl)-3,6-dimethylcarbazole, N-(4-phosphonophenyl)-2,7-dimethoxycarbazole, and N-(4-phosphonophenyl)-2,7-dimethylcarbazole.

[0012] In the above-described perovskite solar cell, when the hole transport layer is self-assembled monolayer I, the ratio of the number of moles of the phenethylamine compound to the total number of moles of the compounds constituting self-assembled monolayer I may be 0.1 mol % or more and 10 mol % or less.

[0013] In the above-described perovskite solar cell, when the hole transport layer is self-assembled monolayer II, the substituent on the 9H-carbazol-9-yl group in the carbazole compound (C1) and the carbazole compound (C2) may be an alkoxy group having from 1 to 6 carbon atoms.

[0014] In the above-described perovskite solar cell, when the hole transport layer is a self-assembled monolayer II, the self-assembled monolayer II may contain a carbazole compound (C1) in which n2 is 2.

[0015] In the above-described perovskite solar cell, when the hole transport layer is a self-assembled monolayer II and the self-assembled monolayer II contains a carbazole compound (C1) in which n2 is 2, -(Ph ２ ) ｎ２ The group represented by - may be a biphenyl-4,4'-diyl group.

[0016] In the above-described perovskite solar cell, when the hole transport layer is a self-assembled monolayer II, the self-assembled monolayer II may contain a carbazole compound (C2) in which a substituent is bonded to the 3-position of a 9H-carbazol-9-yl group.

[0017] In the above-described perovskite solar cell, when the hole transport layer is a self-assembled monolayer III, n3 may be 1.

[0018] In the above-mentioned perovskite solar cell, when the hole transport layer is a self-assembled monolayer III, Ph ３ may be a p-phenylene group.

[0019] In the above-described perovskite solar cell, when the hole transport layer is self-assembled monolayer VI, the phosphono group-containing carbazole compound is selected from the group consisting of N-(2-phosphonoethyl)carbazole, N-(2-phosphonoethyl)-3,6-dimethoxycarbazole, N-(2-phosphonoethyl)-3,6-dimethylcarbazole, N-(2-phosphonoethyl)-2,7-dimethoxycarbazole, N-(2-phosphonoethyl)-2,7-dimethylcarbazole, N-(3-phosphonopropyl)carbazole, N-(3-phosphonopropyl)-3,6-dimethoxycarbazole, N-(3-phosphonopropyl)-3,6-dimethylcarbazole, N-(3-phosphonopropyl)-2,7-dimethoxycarbazole, N-(3-phosphonopropyl)-2,7-dimethylcarbazole, and N-(

[0043] The compound may contain one or more selected from the group consisting of N-(4-phosphonobutyl)carbazole, N-(4-phosphonobutyl)-3,6-dimethoxycarbazole, N-(4-phosphonobutyl)-3,6-dimethylcarbazole, N-(4-phosphonobutyl)-2,7-dimethoxycarbazole, N-(4-phosphonobutyl)-2,7-dimethylcarbazole, N-(4-phosphonophenyl)carbazole, N-(4-phosphonophenyl)-3,6-dimethoxycarbazole, N-(4-phosphonophenyl)-3,6-dimethylcarbazole, N-(4-phosphonophenyl)-2,7-dimethoxycarbazole, and N-(4-phosphonophenyl)-2,7-dimethylcarbazole.

[0020] In the above-described perovskite solar cell, when the hole transport layer is a self-assembled monolayer VI, the ratio of the number of moles of the heteroatom-containing carbazole compound to the total number of moles of the compounds constituting the self-assembled monolayer VI may be 0.1 mol % or more and 10 mol % or less.

[0021] In the above-described perovskite solar cell, when the hole transport layer is self-assembled monolayer VI, the heteroatom-containing carbazole compound may be a compound represented by formula (4-2), the heteroatom may be a halogen atom, and the heteroatom-containing group may be a group containing one or more heteroatoms selected from the group consisting of oxygen atoms, sulfur atoms, nitrogen atoms, phosphorus atoms, and silicon atoms.

[0022] In the above-described perovskite solar cell, when the hole transport layer is self-assembled monolayer VI, the ratio of the mass of the heteroatom-containing carbazole compound to the total mass of the phosphono group-containing carbazole compound and the heteroatom-containing carbazole compound may be 1 mass% or more and 30 mass% or less.

[0023] The liquid composition for forming a hole transport layer according to one embodiment of the present invention is a compound represented by the following formula (1-1): (HO) ２ P(=O)-(CH ２ ) ｎ１ -X １ -Ph １ -CH ２ CH ２ -NH ２ (1-1) (In formula (1-1), n1 is an integer of 0 to 10, and X １ is a single bond, an oxygen atom, -NR-, or a sulfur atom, and Ph １ is a phenylene group which may have a substituent, and R is a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, or ２ P(=O)-(Ph ２ ) ｎ２ -Cbz １ (2-1) (In formula (2-1), Ph ２ is a phenylene group which may be substituted with an alkyl group having from 1 to 6 carbon atoms and / or an alkoxy group having from 1 to 6 carbon atoms, and Cbz １ is a 9H-carbazole-9-yl group optionally substituted with one or more substituents selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom, and n2 is an integer of from 2 to 10. ２ P(=O)-Ph ２ -Cbz ２ (2-2) (In formula (2-2), Ph ２is a phenylene group which may be substituted with an alkyl group having from 1 to 6 carbon atoms and / or an alkoxy group having from 1 to 6 carbon atoms, and Cbz ２ is a 9H-carbazol-9-yl group substituted with one or more substituents selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom; and Cbz ２ The number of substituents on the 9H-carbazol-9-yl group as the carbazole compound (C2) is one. ２ P(=O)-(Ph ３ ) ｎ３ -Cbz ３ (3-1) (In formula (3-1), Ph ３ is a phenylene group which may be substituted with an alkyl group having from 1 to 6 carbon atoms and / or an alkoxy group having from 1 to 6 carbon atoms, and Cbz ３ is a 9H-carbazole-9-yl group optionally substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms and a halogen atom, and n3 is an integer of from 1 to 10), or ２ P(=O)-R １ -Cbz ４ (4-1) (In formula (4-1), R １ is a divalent organic group, and Cbz ４ is a 9H-carbazol-9-yl group which may be substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom. ２ -R ２ -Cbz ４ (4-2) Cbz ４ -R ２ - (S) ｎ４ -R ２ -Cbz ４(4-3) (In formula (4-2), X ２ is a heteroatom or a heteroatom-containing group, and R ２ is a divalent hydrocarbon group, and X ２ is a heteroatom-containing group, R ２ The divalent hydrocarbon group represented by Cbz is bonded to a heteroatom in the heteroatom-containing group. ４ is Cbz in formula (4-1). ４ In formula (4-3), Cbz ４ is Cbz in formula (4-1). ４ is the same as R ２ is R in formula (4-2). ２ and n4 represents an integer of 2 to 8.

[0024] The phenethylamine compound according to one embodiment of the present invention is represented by the following formula (1-1): (HO) ２ P(=O)-(CH ２ ) ｎ１ -X １ -Ph １ -CH ２ CH ２ -NH ２ (1-1) (In formula (1-1), n1 is an integer of 0 to 10, and X １ is a single bond, an oxygen atom, -NR-, or a sulfur atom, and Ph １ is a phenylene group which may have a substituent, and R is a hydrogen atom or a hydrocarbon group having from 1 to 6 carbon atoms.

[0025] The carbazole compound according to one embodiment of the present invention is represented by the following formula (2-1): (HO) ２ P(=O)-(Ph ２ ) ｎ２ -Cbz １ (2-1) (In formula (2-1), Ph represents a phenylene group which may be substituted with an alkyl group having 1 to 6 carbon atoms and / or an alkoxy group having 1 to 6 carbon atoms; Cbz represents a phenylene group which may be substituted with an alkyl group having 1 to 6 carbon atoms; １is a 9H-carbazole-9-yl group optionally substituted with one or more substituents selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom, and n2 is an integer of from 2 to 10. ２ P(=O)-Ph ２ -Cbz ２ (2-2) (In formula (2-2), Ph ２ is a phenylene group which may be substituted with an alkyl group having from 1 to 6 carbon atoms and / or an alkoxy group having from 1 to 6 carbon atoms, and Cbz ２ is a 9H-carbazol-9-yl group substituted with one or more substituents selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom; and Cbz ２ The number of substituents on the 9H-carbazole-9-yl group as the carbazole compound (C2-2) is one.

[0026] The carbazole compound according to one embodiment of the present invention is represented by the following formula (3-1): (HO) ２ P(=O)-(Ph ３ ) ｎ３ -Cbz ３ (3-1) (In formula (3-1), Ph ３ is a phenylene group which may be substituted with an alkyl group having from 1 to 6 carbon atoms and / or an alkoxy group having from 1 to 6 carbon atoms, and Cbz ３ is a 9H-carbazol-9-yl group which may be substituted with one or more groups selected from the group consisting of alkyl groups having from 1 to 6 carbon atoms and halogen atoms, and n ３ is an integer of 1 or more and 10 or less.

[0027] According to the present invention, it is possible to provide a perovskite solar cell with high photoelectric conversion efficiency, a liquid composition that is suitably used for forming a hole transport layer in the perovskite solar cell, and a phenethylamine compound and a carbazole compound that can be suitably incorporated into the liquid composition.

[0028] 1 is a schematic cross-sectional view showing the configuration of an embodiment of a solar cell according to the present invention; 2 is a flowchart showing the procedure of an embodiment of a solar cell manufacturing method according to the present invention;

[0029] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the dimensions of various components in the drawings have been adjusted for clarity and convenience. In addition, in embodiments described later, components similar to those in embodiments described earlier will be designated by the same reference numerals, and redundant description will be omitted.

[0030] [Embodiment] Figure 1 is a schematic cross-sectional view showing the configuration of a perovskite solar cell 1 according to an embodiment of the present invention. The perovskite solar cell 1 comprises a plate- or sheet-shaped substrate 10, a first electrode layer 20 laminated on one main surface of the substrate 10 (the lower side in Figure 1), a hole transport layer 30 laminated on one surface of the first electrode layer 20, a photoelectric conversion layer 40 laminated on one surface of the hole transport layer 30, a passivation layer 50 laminated on one surface of the photoelectric conversion layer 40, an electron transport layer 60 laminated on one side of the passivation layer 50, and a second electrode layer 70 (cathode) laminated on one side of the electron transport layer 60. The passivation layer 50 is an optional layer.

[0031] The substrate 10 is a structure that supports the other layers and ensures the strength of the perovskite solar cell 1. When the perovskite solar cell 1 receives light from the substrate 10 side, the substrate 10 is formed from a transparent material. Specifically, when the strength of the solar cell 1 is important, the substrate 10 is preferably made of glass. When the lightweight and flexible properties of the solar cell 1 are important, the substrate 10 is preferably made of resin. Preferred resin materials for the substrate 10 include polyimide, polyamide, and polyethylene terephthalate. From the viewpoint of dimensional stability, polyimide is particularly preferable. When product cost is important, polyethylene terephthalate is particularly preferable. Furthermore, when the perovskite solar cell 1 receives light from the second electrode layer 70 side, the substrate 10 may be formed from a composite material including a metal layer, or the like.

[0032] The first electrode layer 20 collects holes generated in the photoelectric conversion layer 40 through the hole transport layer 30 and outputs them to the outside. The first electrode layer 20 may be formed of a transparent conductive oxide (TCO) having electrical conductivity and optical transparency. Examples of transparent conductive oxides that can be used to form the first electrode layer 20 include indium oxide, tin oxide, zinc oxide, titanium oxide, and composite oxides thereof. Among these, indium-based composite oxides containing indium oxide, zinc oxide, tungsten oxide, molybdenum oxide, or the like as their main components, and fluorine-doped tin oxide are preferred. From the viewpoints of high electrical conductivity and transparency, indium oxide is particularly preferred. The first electrode layer 20 is preferably subjected to a surface treatment, such as ozone treatment, to improve the formability of the hole transport layer 30. The first electrode layer 20 may have a multilayer structure having a p-type oxide semiconductor layer, for example, containing nickel oxide, niobium oxide, or the like as its main component, on its surface.

[0033] The hole transport layer 30 effectively transfers holes generated in the photoelectric conversion layer 40 to the first electrode layer 20. The hole transport layer 30 is a self-assembled monolayer (SAM) made of compounds that constitute the hole transport layer 30. The hole transport layer 30 is selected from the following self-assembled monolayers I to VI.

[0034] Hereinafter, the self-assembled monolayers I to VI serving as the hole transport layer 30 will be described respectively.

[0035] (Self-assembled monolayer I) The self-assembled monolayer I is represented by the following formula (1-1): (HO) ２ P(=O)-(CH ２ ) ｎ１ -X １ -Ph １ -CH ２ CH ２ -NH ２ (1-1) (In formula (1-1), n1 is an integer of 0 to 10, and X １ is a single bond, an oxygen atom, -NR-, or a sulfur atom, and Ph １ is a phenylene group which may have a substituent, and R is a hydrogen atom or a hydrocarbon group having from 1 to 6 carbon atoms.

[0036] The phenethylamine compound represented by formula (1-1) not only constitutes a self-assembled monolayer I as the hole transport layer 30, but also exhibits a passivation effect, thereby suppressing the recombination of electrons and holes at the interface between the hole transport layer and the perovskite layer, making it possible to produce a perovskite solar cell 1 with high photoelectric conversion efficiency.

[0037] In formula (1-1), Ph １is a phenylene group which may have a substituent. The type of the substituent is not particularly limited as long as the desired effect is not impaired. Examples of the substituent include alkyl groups having 1 to 6 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and an n-hexyl group; a methoxy group, an ethoxy group, an n-propyloxy group, an isopropyloxy group, an n-butyloxy group, an isobutyloxy group, a sec-butyloxy group, a tert-butyloxy group, an n-pentyloxy group, and an n-hexyloxy group. aliphatic acyl groups having from 2 to 6 carbon atoms, such as an acetyl group, a propionyl group, a butanoyl group, a pentanoyl group, and a hexanoyl group; aliphatic acyloxy groups having from 2 to 6 carbon atoms, such as an acetyloxy group, a propionyloxy group, a butanoyloxy group, a pentanoyloxy group, and a hexanoyloxy group; halogen atoms, such as a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom; a nitro group; and a cyano group.

[0038] Ph １ There is no particular limitation on the number of substituents that the phenylene group represented by Ph may have. When the phenylene group represented by Ph has a substituent, the number of the substituents is 1 to 4, and preferably 1 or 2.

[0039] Ph １ The phenylene group which may have a substituent as the substituent is preferably an unsubstituted phenylene group. The unsubstituted phenylene group may be any of a p-phenylene group, an m-phenylene group, and an o-phenylene group, with a p-phenylene group and an m-phenylene group being preferred, and a p-phenylene group being more preferred.

[0040] In formula (1-1), n1 is an integer of 1 or more and 10 or less. n1 is preferably 1 or more and 6 or less, and more preferably 2 or more and 4 or less.

[0041] In formula (1-1), X １ is a single bond, an oxygen atom, —NR—, or a sulfur atom. １is preferably an oxygen atom or a sulfur atom, more preferably an oxygen atom. R is a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms.

[0042] The method for producing the phenethylamine compound represented by formula (1-1) is not particularly limited. The phenethylamine compound represented by formula (1-1) can be synthesized, for example, by the following method.

[0043] Below, X １ A method for synthesizing phenethylamine represented by formula (1-1) will be described below, taking as an example the case where is an oxygen atom. First, the amino group of a compound represented by the following formula (1-1a) is protected with a protecting group (PG) in a conventional manner. Examples of the protecting group include a tert-butoxycarbonyl group (Boc group). When the amino group is protected with a Boc group, for example, the amino group can be protected with di-tert-butyl dicarbonate ((Boc) ２ O). In this way, a compound represented by the following formula (1-1b) is obtained. Next, a haloalkylphosphonic acid diester represented by the following formula (1-1c) and the compound represented by formula (1-1b) are condensed according to the known Williamson etherification reaction method to obtain a compound represented by the following formula (1-1d). In formula (1-1c), R ０１ is a monovalent organic group, preferably a hydrocarbon group. The hydrocarbon group is preferably an alkyl group, more preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group or an ethyl group. In the compound represented by the following formula (1-1d), the protecting group PG is removed by a method depending on the type of protecting group PG, and the phosphonate ester is hydrolyzed to obtain X in formula (1-1). １ is O, a compound represented by the following formula (1-1e) is obtained.

[0044] HO-Ph １ -CH ２ CH ２ -NH ２ ...(1-1a) HO-Ph １ -CH ２ CH ２ -NH-PG...(1-1b) (R ０１O) ２ P(=O)-(CH ２ ) ｎ１ -Hal... (1-1c) (R ０１ O) ２ P(=O)-(CH ２ ) ｎ１ -O-Ph １ -CH ２ CH ２ -NH-PG...(1-1d) (HO) ２ P(=O)-(CH ２ ) ｎ１ -O-Ph １ -CH ２ CH ２ -NH ２ (1-1e) (In formulas (1-1a) to (1-1e), Ph １ , and n1 are the same as those in formula (1-1). PG is a protecting group. Hal is a halogen atom. R ０１ is a monovalent organic group.

[0045] X １ When X is S, the hydroxyl group in the compound represented by formula (1-1a) is changed to a mercapto group, and X １ The phenethylamine compound represented by formula (1-1) can be synthesized in the same manner as when is O.

[0046] X in formula (1-1) １ A compound in which X is —NR— can be synthesized, for example, by the following method. First, the amino group of a compound represented by the following formula (1-1f) is protected with a protecting group (PG) according to a conventional method to obtain a compound represented by the following formula (1-1g). Next, the compound represented by the formula (1-1g) is coupled with an aminoalkylphosphonate ester represented by the following formula (1-1h) by a method such as Buchwald-Hartwig cross-coupling to obtain a compound represented by the following formula (1-1i). In the compound represented by the following formula (1-1i), deprotection is carried out by a method depending on the type of protecting group PG, and the phosphonate ester is hydrolyzed, to obtain a compound represented by the following formula (1-1j), which is a compound in which X in formula (1-1) is —NR—.

[0047] Hal-Ph １ -CH ２ CH ２ -NH ２ ...(1-1f) Hal-Ph １ -CH ２ CH ２ -NH-PG...(1-1g) (R ０１ O) ２ P(=O)-(CH ２ ) ｎ -NRH...(1-1h) (R ０１ O) ２ P(=O)-(CH ２ ) ｎ -NR-Ph １ -CH ２ CH ２ -NH-PG...(1-1i) (HO) ２ P(=O)-(CH ２ ) ｎ -NR-Ph-CH ２ CH ２ -NH ２ ...(1-1j) (In formulas (1-1f) to (1-1j), Ph １ , R, and n1 are the same as those in formula (1-1). PG is a protecting group. Hal is a halogen atom. R ０１ is a monovalent organic group.

[0048] Specific preferred examples of the phenethylamine compound represented by formula (1-1) described above include 2-[4-(2-phosphonoethyloxy)phenyl]ethylamine, 2-[3-(2-phosphonoethyloxy)phenyl]ethylamine, 2-[2-(2-phosphonoethyloxy)phenyl]ethylamine, 2-[4-(3-phosphonopropyloxy)phenyl]ethylamine, 2-[3-(3-phosphonopropyloxy)phenyl]ethylamine, 2-[2-(3-phosphonopropyloxy)phenyl]ethylamine, 2-[4-(4-phosphonobutyloxy)phenyl]ethylamine, )phenyl]ethylamine, 2-[3-(4-phosphonobutyloxy)phenyl]ethylamine, 2-[2-(4-phosphonobutyloxy)phenyl]ethylamine, 2-[4-(2-phosphonoethylamino)phenyl]ethylamine, 2-[3-(2-phosphonoethylamino)phenyl]ethylamine, 2-[2-(2-phosphonoethylamino)phenyl]ethylamine, 2-[4-(3-phosphonopropylamino)phenyl]ethylamine, 2-[3-(3-phosphonopropylamino)phenyl]ethylamine, 2-[2-(3-phosphonopropyl amino)phenyl]ethylamine, 2-[4-(4-phosphonobutylamino)phenyl]ethylamine, 2-[3-(4-phosphonobutylamino)phenyl]ethylamine, 2-[2-(4-phosphonobutylamino)phenyl]ethylamine, 2-[4-(2-phosphonoethylthio)phenyl]ethylamine, 2-[3-(2-phosphonoethylthio)phenyl]ethylamine, 2-[2-(2-phosphonoethylthio)phenyl]ethylamine, 2-[4-(3-phosphonopropylthio)phenyl]ethylamine, 2-[3-(3-phosphonopropylthio)phenyl]ethylamine e) phenyl]ethylamine, 2-[2-(3-phosphonopropylthio)phenyl]ethylamine, 2-[4-(4-phosphonobutylthio)phenyl]ethylamine, 2-[3-(4-phosphonobutylthio)phenyl]ethylamine, 2-[2-(4-phosphonobutylthio)phenyl]ethylamine, 2-[4-(2-phosphonoethyl)phenyl]ethylamine, 2-[3-(2-phosphonoethyl)phenyl]ethylamine, 2-[2-(2-phosphonoethyl)phenyl]ethylamine, 2-[4-(3-phosphonopropyl)phenyl]ethylamine,Examples include 2-[3-(3-phosphonopropyl)phenyl]ethylamine, 2-[2-(3-phosphonopropyl)phenyl]ethylamine, 2-[4-(4-phosphonobutyl)phenyl]ethylamine, 2-[3-(4-phosphonobutyl)phenyl]ethylamine, and 2-[2-(4-phosphonobutyl)phenyl]ethylamine.

[0049] The ratio of the number of moles of the phenethylamine compound to the total number of moles of compounds constituting the self-assembled monolayer I as the hole transport layer 30 is not particularly limited as long as the desired effect is not impaired. The ratio of the number of moles of the phenethylamine compound to the total number of moles of compounds constituting the self-assembled monolayer I as the hole transport layer 30 is preferably 0.1 mol % to 70 mol %, more preferably 0.1 mol % to 10 mol %, even more preferably 1 mol % to 9 mol %, still more preferably 1.5 mol % to 8 mol %, and particularly preferably 2 mol % to 7 mol %.

[0050] The self-assembled monolayer I serving as the hole transport layer 30 preferably contains a carbazole compound (C0) together with the phenethylamine compound represented by formula (1). The carbazole compound (C0) preferably has a functional group such as a phosphonic acid group, a carboxy group, a sulfonic acid group, a boric acid group, a hydroxy group, an amino group, or a mercapto group. Among these, the phosphonic acid group, the carboxy group, the amino group, and the mercapto group are particularly preferred, with the phosphonic acid group and the mercapto group being more preferred. When the carbazole compound (C0) has these functional groups, the interaction between these functional groups and the surface of the first electrode layer 20 facilitates the formation of a self-assembled monolayer serving as the hole transport layer 30.

[0051] When the self-assembled monolayer I as the hole transport layer 30 contains a carbazole compound (C0), the carbazole compound (C0) is selected from the group consisting of N-(2-phosphonoethyl)carbazole (2PACz), N-(2-phosphonoethyl)-3,6-dimethoxycarbazole (MeO-2PACz), N-(2-phosphonoethyl)-3,6-dimethylcarbazole (Me-2PACz), N-(2-phosphonoethyl)-2,7-dimethoxycarbazole, ... N-(3-phosphonopropyl)-2,7-dimethylcarbazole, N-(3-phosphonopropyl)carbazole (3PACz), N-(3-phosphonopropyl)-3,6-dimethoxycarbazole (MeO-3PACz), N-(3-phosphonopropyl)-3,6-dimethylcarbazole (Me-3PACz), N-(3-phosphonopropyl)-2,7-dimethoxycarbazole, N-(3-phosphonopropyl)-2,7-dimethylcarbazole, N-(4-phosphonopropyl)-2,7-dimethylcarbazole N-(4-phosphonobutyl)carbazole (4PACz), N-(4-phosphonobutyl)-3,6-dimethoxycarbazole (MeO-4PACz), N-(4-phosphonobutyl)-3,6-dimethylcarbazole (Me-4PACz), N-(4-phosphonobutyl)-2,7-dimethoxycarbazole, N-(4-phosphonobutyl)-2,7-dimethylcarbazole, N-(4-phosphonophenyl)carbazole, N-(4-phosphonophenyl)-3,6-dimethylcarbazole Preferably, the compound contains one or more selected from the group consisting of N-(4-phosphonophenyl)-3,6-dimethylcarbazole, N-(4-phosphonophenyl)-2,7-dimethoxycarbazole, and N-(4-phosphonophenyl)-2,7-dimethylcarbazole, and more preferably contains one or more selected from the group consisting of 2PACz, MeO-2PACz, Me-2PACz, MeO-4PACz, and Me-4PACz.

[0052] The self-assembled monolayer I serving as the hole transport layer 30 may contain, as a compound other than the phenethylamine compound represented by formula (1-1), phosphonic acid compounds such as n-butylphosphonic acid, n-pentylphosphonic acid, n-hexylphosphonic acid, n-octylphosphonic acid, n-decylphosphonic acid, n-octadecylphosphonic acid, 2-ethylhexylphosphonic acid, methoxymethylphosphonic acid, 3-acryloyloxypropylphosphonic acid, 11-hydroxyundecylphosphonic acid, and 1H,1H,2H,2H-perfluorophosphonic acid, as well as compounds such as acetic acid, propionic acid, isobutyric acid, nonanoic acid, fluoroacetic acid, α-chloropropionic acid, and glyoxylic acid. These compounds may be used alone or in combination of two or more.

[0053] The self-assembled monolayer I serving as the hole transport layer 30 more preferably contains one or more selected from the group consisting of 2PACz, MeO-2PACz, and Me-4PACz, and even more preferably contains 2PACz and / or MeO-2PACz. The self-assembled monolayer I serving as the hole transport layer 30 containing one or more selected from the group consisting of 2PACz, MeO-2PACz, and Me-4PACz has sufficient hole-selective function, and therefore, even when the photoelectric conversion layer 40 is directly laminated thereon, it is easy to efficiently extract holes while blocking electrons.

[0054] When the self-assembled monolayer I serving as the hole transport layer 30 contains 2PACz and MeO-2PACz, the lower limit of the mass ratio of 2PACz to MeO-2PACz (the proportion of 2PACz) in the self-assembled monolayer I serving as the hole transport layer 30 is preferably 1:99, and more preferably 10:90. On the other hand, the upper limit of the mass ratio of 2PACz to MeO-2PACz is preferably 60:40, more preferably 55:45, even more preferably 50:50, and particularly preferably 30:70. When the mass ratio of 2PACz to MeO-2PACz is within the above range, it is easy to form a hole transport layer 30 with few pinholes, and further, the hole transport layer 30 has appropriate wettability with the photoelectric conversion layer-forming material solution for forming the photoelectric conversion layer 40, making it easy to appropriately form the photoelectric conversion layer 40. This optimizes the generation of carriers (holes and electrons) by the photoelectric conversion layer 40 and the transfer of holes from the photoelectric conversion layer 40 to the hole transport layer 30, thereby improving the photoelectric conversion efficiency of the perovskite solar cell 1.

[0055] The self-assembled monolayer I serving as the hole transport layer 30 can be formed by applying and drying a liquid composition containing the phenethylamine compound represented by formula (1-1) described above. The liquid composition may contain a compound other than the phenethylamine compound represented by formula (1-1) in addition to the phenethylamine compound represented by formula (1-1). As described above, the compound other than the phenethylamine compound represented by formula (1-1) is preferably a carbazole compound. Furthermore, the carbazole compound preferably includes one or more compounds selected from the group consisting of N-(2-phosphonoethyl)carbazole (2PACz), N-(2-phosphonoethyl)-3,6-dimethoxycarbazole (MeO-2PACz), and N-(4-phosphonoethyl)-3,6-dimethylcarbazole (Me-4PACz), and more preferably includes 2PACz and / or MeO-2PACz.

[0056] (Self-assembled monolayer II) The self-assembled monolayer II is represented by the following formula (2-1): (HO) ２ P(=O)-(Ph ２ ) ｎ２ -Cbz １(2-1) (In formula (2-1), Ph ２ is a phenylene group which may be substituted with an alkyl group having from 1 to 6 carbon atoms and / or an alkoxy group having from 1 to 6 carbon atoms, and Cbz １ is a 9H-carbazole-9-yl group optionally substituted with one or more substituents selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom, and n2 is an integer of from 2 to 10. ２ P(=O)-Ph ２ -Cbz ２ (2-2) (In formula (2-2), Ph ２ is a phenylene group which may be substituted with an alkyl group having from 1 to 6 carbon atoms and / or an alkoxy group having from 1 to 6 carbon atoms, and Cbz ２ is a 9H-carbazol-9-yl group substituted with one or more substituents selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom; and Cbz ２ The number of substituents on the 9H-carbazol-9-yl group as the self-assembled monolayer is one.

[0057] In formula (2-1) and formula (2-2), Ph ２is a phenylene group which may be substituted with an alkyl group having from 1 to 6 carbon atoms and / or an alkoxy group having from 1 to 6 carbon atoms. Examples of the alkyl group having from 1 to 6 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and an n-hexyl group. Examples of the alkoxy group having from 1 to 6 carbon atoms include a methoxy group, an ethoxy group, an n-propyloxy group, an isopropyloxy group, an n-butyloxy group, an isobutyloxy group, a sec-butyloxy group, a tert-butyloxy group, an n-pentyloxy group, and an n-hexyloxy group.

[0058] In formula (2-1), n2 is an integer of 2 or more and 10 or less. n2 is preferably 2 or more and 6 or less, more preferably 2 or more and 4 or less, and even more preferably 2 or 3.

[0059] Ph ２ The number of substituents that the phenylene group may have is not particularly limited. ２ When the phenylene group as has a substituent, the number of the substituents is 1 or more and 4 or less, and 1 or 2 is preferred.

[0060] Ph ２ The phenylene group which may have a substituent as shown in formula (2-1) is preferably an unsubstituted phenylene group. The unsubstituted phenylene group may be any of a p-phenylene group, an m-phenylene group, and an o-phenylene group, with a p-phenylene group and an m-phenylene group being preferred, and a p-phenylene group being more preferred. In formula (2-1), n2 is an integer of 2 or more and 10 or less. ２ may be different or the same.

[0061] -(Ph) in formula (2-1) ｎ２Specific preferred examples of the group represented by - include biphenyl-4,4'-diyl group, biphenyl-3,4'-diyl group, biphenyl-2,4'-diyl group, biphenyl-3,3'-diyl group, biphenyl-2,3'-diyl group, biphenyl-2,2'-diyl group, p-terphenyl-4,4"-diyl group, m-terphenyl-4,4"-diyl group, p-terphenyl-3,4"-diyl group, and m-terphenyl-3,4"-diyl group. Of these groups, biphenyl-4,4'-diyl group, biphenyl-3,4'-diyl group, and biphenyl-3,3'-diyl group are more preferred.

[0062] -Ph in formula (2-2) ２ Specific preferred examples of the group represented by - include a p-phenylene group, an m-phenylene group, and an o-phenylene group. Of these groups, a p-phenylene group and an m-phenylene group are preferred.

[0063] In formula (2-1), Cbz １ is a 9H-carbazol-9-yl group which may be substituted with one or more substituents selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom. ２ Cbz is a 9H-carbazol-9-yl group substituted with one or more substituents selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom. ２ The number of substituents that the 9H-carbazol-9-yl group has as a substituent is 1. Hereinafter, the "9H-carbazol-9-yl group" may be referred to as a "carbazolyl group."

[0064] Cbz １ , or Cbz ２ The alkyl group and alkoxy group that may be substituted by Cbz are the same as the alkyl group and alkoxy group that may be substituted by Ph. １ , or Cbz ２ The alkyl group which may be substituted by Cbz is preferably a methyl group or an ethyl group. １, or Cbz ２ The alkoxy group which may be substituted by is preferably a methoxy group or an ethoxy group.

[0065] Cbz １ , or Cbz ２ Examples of halogen atoms that may be substituted by Cbz include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. １ , or Cbz ２ The halogen atom which may be contained as a substituent is preferably a fluorine atom, a chlorine atom, or a bromine atom.

[0066] Cbz １ , or Cbz ２ In the formula (Cbz), the position of the substituent on the carbazole ring is not particularly limited as long as the desired effect is not impaired. １ has one or more substituents selected from the group consisting of an alkyl group, an alkoxy group, and a halogen atom, Cbz １ is preferably a mono-substituted carbazolyl group substituted at the 2- or 3-position, a 3,6-di-substituted carbazolyl group substituted at the 3- and 6-positions, or a 2,7-di-substituted carbazolyl group substituted at the 2- and 7-positions. ２ is preferably a mono-substituted carbazolyl group substituted at the 2- or 3-position, and more preferably a mono-substituted carbazolyl group substituted at the 3-position.

[0067] Cbz １Specific preferred examples of the 9H-carbazol-9-yl group include a 9H-carbazol-9-yl group, a 2-methyl-9H-carbazol-9-yl group, a 2-methoxy-9H-carbazol-9-yl group, a 2-bromo-9H-carbazol-9-yl group, a 2-iodo-9H-carbazol-9-yl group, a 3-methyl-9H-carbazol-9-yl group, a 3-methoxy-9H-carbazol-9-yl group, a 3-bromo-9H-carbazol-9-yl group, a 3-iodo-9H-carbazol-9-yl group, a 2, Examples thereof include a 7-dimethyl-9H-carbazol-9-yl group, a 2,7-dimethoxy-9H-carbazol-9-yl group, a 2,7-dibromo-9H-carbazol-9-yl group, a 2,7-diiodo-9H-carbazol-9-yl group, a 3,6-dimethyl-9H-carbazol-9-yl group, a 3,6-dimethoxy-9H-carbazol-9-yl group, a 3,6-dibromo-9H-carbazol-9-yl group, and a 3,6-diiodo-9H-carbazol-9-yl group.

[0068] Cbz ２ Specific preferred examples of the 9H-carbazol-9-yl group include a 2-methyl-9H-carbazol-9-yl group, a 2-methoxy-9H-carbazol-9-yl group, a 2-bromo-9H-carbazol-9-yl group, a 2-iodo-9H-carbazol-9-yl group, a 3-methyl-9H-carbazol-9-yl group, a 3-methoxy-9H-carbazol-9-yl group, a 3-bromo-9H-carbazol-9-yl group, and a 3-iodo-9H-carbazol-9-yl group.

[0069] In the compound represented by formula (2-1) and the compound represented by formula (2-2), it is preferable that the difference between the HOMO (Highest Occupied Molecular Orbital) and the HOMO of the perovskite compound constituting the photoelectric conversion layer 40 is small. The HOMO difference is preferably 0.00 to 1.00 eV, more preferably 0.00 to 0.50 eV, and even more preferably 0.00 to 0.30 eV. The HOMO can be determined by photoelectron spectroscopy or quantum chemical calculations based on density functional theory. In this case, B3LYP can be used as the exchange-correlation functional, and 6-311G(d) and 6-311++G(d,p) can be used as the basis functions for optimizing the molecular structure and calculating the energy, respectively.

[0070] The method for producing the carbazole compound (C1) represented by formula (2-1) and the carbazole compound (C2) represented by formula (2-2) is not particularly limited. The carbazole compound (C1) and the carbazole compound (C2) can be synthesized, for example, by the following method.

[0071] The carbazole compound (C1) represented by formula (2-1) can be synthesized, for example, by the following method. Specifically, first, a haloarylphosphonic acid diester represented by the following formula (2-1a) and H-Cbz １ and a carbazole compound represented by the formula: ２ ) or the like, according to a known method, to obtain a carbazole compound having a phosphonic acid diester group represented by the following formula (2-1b): ０１ is a monovalent organic group, preferably a hydrocarbon group. The hydrocarbon group is preferably an alkyl group, more preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group or an ethyl group. The haloarylphosphonic acid diester represented by formula (2-1a) is prepared by reacting one halogen atom of a dihalogenated aromatic compound represented by the following formula (2-1c) with (R ０１ O) ２ A phosphorous acid diester represented by P(=O)H was reacted with palladium acetate (Pd(OAc)２ The carbazole compound (C1) represented by formula (2-1) can be obtained by reacting the carbazole compound (C1) represented by formula (2-1) in the presence of a transition metal catalyst such as methyl methyl ether. Next, the phosphonate diester group in the carbazole compound having the phosphonate diester group represented by formula (2-1b) is hydrolyzed by a well-known method. (R ０１ O) ２ P(=O)-(Ph ２ ) ｎ２ -Hal (2-1a) (R ０１ O) ２ P(=O)-(Ph ２ ) ｎ２ -Cbz １ (2-1b) Hal-(Ph ２ ) ｎ２ -Hal (2-1c) (in formula (2-1a), formula (2-1b), and formula (2-1c), Ph ２ , n2, and Cbz １ are the same as those in formula (2-1). Hal is a halogen atom. R ０１ is a monovalent organic group.

[0072] The carbazole compound (C2) represented by formula (2-2) can be synthesized, for example, by the following method. Specifically, first, a haloarylphosphonic acid diester represented by the following formula (2-2a) and H-Cbz ２ and a carbazole compound represented by the formula: ２ In the formula (2-2a), R is condensed in the presence of a transition metal catalyst according to a known method to obtain a carbazole compound having a phosphonic acid diester group represented by the following formula (2-2b). ０１ is the same as in formula (2-1a). Next, the phosphonic acid diester group in the carbazole compound having a phosphonic acid diester group represented by formula (2-2b) is hydrolyzed by a well-known method to obtain a carbazole compound (C2) represented by formula (2-2). (R ０１ O) ２ P(=O)-Ph ２ -Hal (2-2a) (R ０１ O) ２P(=O)-Ph ２ -Cbz ２ (2-2b) (In formula (2-2a) and formula (2-2b), Ph ２ , and Cbz ２ are the same as those in formula (2-2). Hal is a halogen atom. R ０１ is a monovalent organic group.

[0073] Preferable specific examples of the carbazole compound (C1) represented by the formula (2-1) described above include N-[4-(4-phosphonophenyl)phenyl]-9H-carbazole (also referred to as [4'-(9H-carbazol-9-yl)biphenyl-4-yl]phosphonic acid), N-[3-(4-phosphonophenyl)phenyl]-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-9H-carbazole, 4-phosphonophenyl N-4"-(9H-carbazol-9-yl)terphenyl, N-[4-(4-phosphonophenyl)phenyl]-2-methyl-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-2-methoxy-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-2-bromo-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-2-iodo-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-3-methyl-9H-carbazole N-[4-(4-phosphonophenyl)phenyl]-3-methoxy-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-3-bromo-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-3-iodo-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-2,7-dimethyl-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-2,7-dimethoxy-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]- N-[4-(4-phosphonophenyl)phenyl]-2,7-dibromo-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-2,7-diiodo-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-3,6-dimethyl-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-3,6-dimethoxy-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-3,6-dibromo-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-3,6-diiodo-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-2-methyl-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-2-methoxy-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-2-bromo-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-2-iodo-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-3-methyl-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-3-methoxy-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-3-bromo-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-3-iodo-9H-carbazole N-[3-(4-phosphonophenyl)phenyl]-2,7-dimethyl-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-2,7-dimethoxy-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-2,7-dibromo-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-2,7-diiodo-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-3,6-dimethyl-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-3,6-dimethoxy-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-3,6-dibromo-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-3,6-diiodo-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-2-methyl-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-2-methoxy-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-2-bromo-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-2-iodo-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-3-methyl-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-3-methoxy-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-3-bromo-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-3-iodo-9H-carbazole N-[4-(3-phosphonophenyl)phenyl]-2,7-dimethyl-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-2,7-dimethoxy-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-2,7-dibromo-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-2,7-diiodo-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-3,6-dimethyl-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-3,6-dimethoxy-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-3,6-dibromo-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-3,6-diiodo-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-2-methyl-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-2-methoxy-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-2-bromo-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-2-iodo-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-3-methyl-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-3-methoxy-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-3-bromo-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-3-iodo-9H-carbazole N-[3-(3-phosphonophenyl)phenyl]-2,7-dimethyl-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-2,7-dimethoxy-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-2,7-dibromo-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-2,7-diiodo-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-3,6-dimethyl-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-3,6-dimethoxy-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-3,6-dibromo-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-3,6-diiodo-9H-carbazole, 4-phosphono-4"-(2-methyl-9H-carbazol-9-yl)-p-terphenyl, 4-phosphono-4"-(2-methoxy-9H-carbazol-9-yl)-p-terphenyl, 4-phosphono-4"-(2-bromo-9H-carbazol-9-yl)-p-terphenyl, 4-phosphono-4"-(2-iodo-9H-carbazol-9-yl)-p-terphenyl phenyl, 4-phosphono-4"-(3-methyl-9H-carbazol-9-yl)-p-terphenyl, 4-phosphono-4"-(3-methoxy-9H-carbazol-9-yl)-p-terphenyl, 4-phosphono-4"-(3-bromo-9H-carbazol-9-yl)-p-terphenyl, 4-phosphono-4"-(3-iodo-9H-carbazol-9-yl)-p-terphenyl, 4-phosphono-4"-(3-iodo-9H-carbazol-9-yl)-p-terphenyl, "-(2,7-dimethyl-9H-carbazol-9-yl)-p-terphenyl, 4-phosphono-4"-(2,7-dimethoxy-9H-carbazol-9-yl)-p-terphenyl, 4-phosphono-4"-(2,7-dibromo-9H-carbazol-9-yl)-p-terphenyl, 4-phosphono-4"-(2,7-diiodo-9H-carbazol-9-yl)-p-terphenyl, 4-phosphono-4"-(2,7-diiodo-9H-carbazol-9-yl)-p-terphenyl, Examples of such phosphono compounds include 4-phosphono-4"-(3,6-dimethyl-9H-carbazol-9-yl)-p-terphenyl, 4-phosphono-4"-(3,6-dimethoxy-9H-carbazol-9-yl)-p-terphenyl, 4-phosphono-4"-(3,6-dibromo-9H-carbazol-9-yl)-p-terphenyl, and 4-phosphono-4"-(3,6-diiodo-9H-carbazol-9-yl)-p-terphenyl.

[0074] Preferable specific examples of the carbazole compound (C2) represented by the formula (2-2) described above include N-(4-phosphonophenyl)-2-methyl-9H-carbazole, N-(4-phosphonophenyl)-2-methoxy-9H-carbazole, N-(4-phosphonophenyl)-2-bromo-9H-carbazole, N-(4-phosphonophenyl)-2-iodo-9H-carbazole, N-(3-phosphonophenyl)-2-methyl-9H-carbazole, N-(3-phosphonophenyl)-2-methoxy-9H-carbazole, N-(3-phosphonophenyl)-2-bromo-9H-carbazole, and N-(3-phosphonophenyl). N-2-iodo-9H-carbazole, N-(4-phosphonophenyl)-3-methyl-9H-carbazole, N-(4-phosphonophenyl)-3-methoxy-9H-carbazole, N-(4-phosphonophenyl)-3-bromo-9H-carbazole, N-(4-phosphonophenyl)-3-iodo-9H-carbazole, N-(3-phosphonophenyl)-3-methyl-9H-carbazole, N-(3-phosphonophenyl)-3-methoxy-9H-carbazole, N-(3-phosphonophenyl)-3-bromo-9H-carbazole, and N-(3-phosphonophenyl)-3-iodo-9H-carbazole.

[0075] The ratio of the total number of moles of the carbazole compound (C1) and the carbazole compound (C2) to the total number of moles of the compounds constituting the self-assembled monolayer II as the hole transport layer 30 is not particularly limited as long as the desired effect is not impaired. The ratio of the total number of moles of the carbazole compound (C1) and the carbazole compound (C2) to the total number of moles of the compounds constituting the self-assembled monolayer II as the hole transport layer 30 is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 90 mol% or more, and particularly preferably 100 mol%.

[0076] The self-assembled monolayer II serving as the hole transport layer 30 may contain one or more carbazole compounds selected from the carbazole compound (C1) and the carbazole compound (C2), as well as a compound other than the carbazole compound (C1) and the carbazole compound (C2). The other compound is preferably a carbazole compound other than the carbazole compound (C1) and the carbazole compound (C2). The other carbazole compound preferably has a functional group such as a phosphonic acid group, a carboxy group, a sulfonic acid group, a boric acid group, a hydroxy group, an amino group, or a mercapto group. Among these, a phosphonic acid group, a carboxy group, an amino group, or a mercapto group is particularly preferred, with a phosphonic acid group and a mercapto group being more preferred. When the carbazole compound has these functional groups, the interaction between the functional group and the surface of the first electrode layer 20 facilitates the formation of a self-assembled monolayer serving as the hole transport layer 30.

[0077] When the self-assembled monolayer II as the hole transport layer 30 contains another carbazole compound, the other carbazole compound may be N-(2-phosphonoethyl)carbazole (2PACz), N-(2-phosphonoethyl)-3,6-dimethoxycarbazole (MeO-2PACz), N-(2-phosphonoethyl)-3,6-dimethylcarbazole (Me-2PACz), N-(2-phosphonoethyl)-2,7-dimethoxycarbazole, N-(2-phosphonoethyl)-3,6-dimethylcarbazole (MeO ... N-(3-phosphonopropyl)-2,7-dimethylcarbazole, N-(3-phosphonopropyl)carbazole (3PACz), N-(3-phosphonopropyl)-3,6-dimethoxycarbazole (MeO-3PACz), N-(3-phosphonopropyl)-3,6-dimethylcarbazole (Me-3PACz), N-(3-phosphonopropyl)-2,7-dimethoxycarbazole, N-(3-phosphonopropyl)-2,7-dimethylcarbazole, N-(4-phosphono N-(4-phosphonobutyl)-3,6-dimethoxycarbazole (MeO-4PACz), N-(4-phosphonobutyl)-3,6-dimethylcarbazole (Me-4PACz), N-(4-phosphonobutyl)-2,7-dimethoxycarbazole, N-(4-phosphonobutyl)-2,7-dimethylcarbazole, N-(4-phosphonophenyl)carbazole, N-(4-phosphonophenyl)-3,6-dimeth Preferably, the compound contains one or more selected from the group consisting of N-(4-phosphonophenyl)-3,6-dimethylcarbazole, N-(4-phosphonophenyl)-2,7-dimethoxycarbazole, and N-(4-phosphonophenyl)-2,7-dimethylcarbazole, and more preferably one or more selected from the group consisting of 2PACz, MeO-2PACz, Me-2PACz, MeO-4PACz, and Me-4PACz.

[0078] The self-assembled monolayer II serving as the hole transport layer 30 may contain, as compounds other than the carbazole compound (C1) and the carbazole compound (C2), n-butylphosphonic acid, n-pentylphosphonic acid, n-hexylphosphonic acid, n-octylphosphonic acid, n-decylphosphonic acid, n-octadecylphosphonic acid, 2-ethylhexylphosphonic acid, methoxymethylphosphonic acid, 3-acryloyloxypropylphosphonic acid, and 11-hydroxyundecylphosphonic acid. Phosphonic acid compounds such as 1H,1H,2H,2H-perfluorophosphonic acid, acetic acid, propionic acid, isobutyric acid, nonanoic acid, fluoroacetic acid, α-chloropropionic acid, and glyoxylic acid. These compounds may be used alone or in combination.

[0079] The self-assembled monolayer II serving as the hole transport layer 30 can be formed by applying and drying a liquid composition containing one or more carbazole compounds selected from the carbazole compound (C1) and the carbazole compound (C2). The liquid composition may contain, in addition to the one or more carbazole compounds selected from the carbazole compound (C1) and the carbazole compound (C2), a compound other than the carbazole compound (C1) and the carbazole compound (C2). As described above, the compound other than the carbazole compound (C1) and the carbazole compound (C2) is preferably one or more compounds selected from the group consisting of N-(2-phosphonoethyl)carbazole (2PACz), N-(2-phosphonoethyl)-3,6-dimethoxycarbazole (MeO-2PACz), and N-(4-phosphonoethyl)-3,6-dimethylcarbazole (Me-4PACz), with 2PACz and / or MeO-2PACz being more preferred.

[0080] (Self-assembled monolayer III) The self-assembled monolayer III is represented by the following formula (3-1): (HO) ２ P(=O)-(Ph ３ ) ｎ３ -Cbz ３ (3-1) (In formula (3-1), Ph ３is a phenylene group which may be substituted with an alkyl group having from 1 to 6 carbon atoms and / or an alkoxy group having from 1 to 6 carbon atoms, and Cbz ３ is a 9H-carbazole-9-yl group optionally substituted with one or more groups selected from the group consisting of alkyl groups having from 1 to 6 carbon atoms and halogen atoms, and n3 is an integer of from 1 to 10.

[0081] In formula (3-1), Ph ３ is a phenylene group which may be substituted with an alkyl group having from 1 to 6 carbon atoms and / or an alkoxy group having from 1 to 6 carbon atoms. Examples of the alkyl group having from 1 to 6 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and an n-hexyl group. Examples of the alkoxy group having from 1 to 6 carbon atoms include a methoxy group, an ethoxy group, an n-propyloxy group, an isopropyloxy group, an n-butyloxy group, an isobutyloxy group, a sec-butyloxy group, a tert-butyloxy group, an n-pentyloxy group, and an n-hexyloxy group.

[0082] In formula (3-1), n3 is an integer of 1 or more and 10 or less. n3 is preferably 1 or more and 6 or less, more preferably 1 or more and 4 or less, and even more preferably 1 or 2.

[0083] Ph ３ The number of substituents that the phenylene group may have is not particularly limited. ３ When the phenylene group as has a substituent, the number of the substituents is 1 or more and 4 or less, and 1 or 2 is preferred.

[0084] Ph ３The phenylene group which may have a substituent as the substituent is preferably an unsubstituted phenylene group. The unsubstituted phenylene group may be any of a p-phenylene group, an m-phenylene group, and an o-phenylene group, with a p-phenylene group and an m-phenylene group being preferred, and a p-phenylene group being more preferred. When n3 is an integer of 2 or more and 10 or less, a plurality of Ph ３ may be different or the same.

[0085] -(Ph in formula (3-1) ３ ) ｎ３ Specific preferred examples of the group represented by - include a p-phenylene group, an m-phenylene group, an o-phenylene group, a biphenyl-4,4'-diyl group, a biphenyl-3,4'-diyl group, a biphenyl-2,4'-diyl group, a biphenyl-3,3'-diyl group, a biphenyl-2,3'-diyl group, and a biphenyl-2,2'-diyl group. Among these groups, a p-phenylene group, an m-phenylene group, a biphenyl-4,4'-diyl group, a biphenyl-3,4'-diyl group, and a biphenyl-3,3'-diyl group are more preferred, a p-phenylene group, an m-phenylene group, a biphenyl-4,4'-diyl group, and a biphenyl-3,4'-diyl group are even more preferred, and a p-phenylene group and a biphenyl-4,4'-diyl group are particularly preferred.

[0086] Cbz ３ is a 9H-carbazol-9-yl group which may be substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms and a halogen atom. Hereinafter, the "9H-carbazol-9-yl group" may be referred to as a "carbazolyl group."

[0087] Cbz ３ Examples of the alkyl group that may be substituted include Ph ３ The alkyl groups which may be substituted by Cbz are the same as those which may be substituted by Cbz. ３ The alkyl group which may be substituted by is preferably a methyl group or an ethyl group.

[0088] Cbz ３Examples of halogen atoms that may be substituted by Cbz include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. ３ The halogen atom which may be contained as a substituent is preferably a fluorine atom, a chlorine atom, or a bromine atom.

[0089] Cbz ３ When Cbz has an alkyl group and / or a halogen atom as a substituent, the position of the substituent on the carbazole ring is not particularly limited as long as the desired effect is not impaired. ３ When Cbz has an alkyl group and / or a halogen atom as a substituent, ３ is preferably a mono-substituted carbazolyl group substituted at the 2- or 3-position, a 3,6-di-substituted carbazolyl group substituted at the 3- and 6-positions, or a 2,7-di-substituted carbazolyl group substituted at the 2- and 7-positions.

[0090] Cbz ３Specific preferred examples of the 9H-carbazol-9-yl group include a 9H-carbazol-9-yl group, a 2-methyl-9H-carbazol-9-yl group, a 2-ethyl-9H-carbazol-9-yl group, a 2-fluoro-9H-carbazol-9-yl group, a 2-chloro-9H-carbazol-9-yl group, a 2-bromo-9H-carbazol-9-yl group, a 2-iodo-9H-carbazol-9-yl group, a 3-methyl-9H-carbazol-9-yl group, a 3-ethyl-9H-carbazol-9-yl group, a 3-fluoro-9H-carbazol-9-yl group, a 3-chloro-9H-carbazol-9-yl group, and a 3-bromo-9H-carbazol-9-yl group. 3-iodo-9H-carbazol-9-yl group, 2,7-dimethyl-9H-carbazol-9-yl group, 2,7-diethyl-9H-carbazol-9-yl group, 2,7-difluoro-9H-carbazol-9-yl group, 2,7-dichloro-9H-carbazol-9-yl group, 2,7-dibromo-9H-carbazol-9-yl group, 2,7-diiodo-9H-carbazole 9H-carbazol-9-yl group, 3,6-dimethyl-9H-carbazol-9-yl group, 3,6-diethyl-9H-carbazol-9-yl group, 3,6-difluoro-9H-carbazol-9-yl group, 3,6-dichloro-9H-carbazol-9-yl group, 3,6-dibromo-9H-carbazol-9-yl group, and 3,6-diiodo-9H-carbazol-9-yl group.

[0091] The compound represented by formula (3-1) is preferably a compound in which the difference between the HOMO (Highest Occupied Molecular Orbital) of the compound and the HOMO of the perovskite compound constituting the photoelectric conversion layer 40 is small. The HOMO difference is preferably 0.00 to 1.00 eV, more preferably 0.00 to 0.50 eV, and even more preferably 0.00 to 0.30 eV. The HOMO can be determined by photoelectron spectroscopy or quantum chemical calculations based on density functional theory. In this case, the exchange-correlation functional is B3LYP, and the basis functions used are 6-311G(d) for optimizing the molecular structure and 6-311++G(d,p) for calculating the energy.

[0092] The method for producing the carbazole compound (C3) represented by formula (3-1) is not particularly limited. The carbazole compound (C3) represented by formula (3-1) can be synthesized, for example, by the following method.

[0093] Specifically, first, a haloarylphosphonic acid diester represented by the following formula (3-1a) and H-Cbz ３ and a carbazole compound represented by the formula: ２ ) or the like, according to a known method, to obtain a carbazole compound having a phosphonic acid diester group represented by the following formula (3-1b): ０１ is a monovalent organic group, preferably a hydrocarbon group. The hydrocarbon group is preferably an alkyl group, more preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group or an ethyl group. Next, the phosphonic acid diester group in the carbazole compound having the phosphonic acid diester group represented by formula (3-1b) is hydrolyzed by a well-known method to obtain the carbazole compound (C3) represented by formula (3-1). (R ０１ O) ２ P(=O)-(Ph ３ ) ｎ３ -Hal (3-1a) (R ０１ O) ２ P(=O)-(Ph ３ ) ｎ３ -Cbz ３ (3-1b) (In formula (3-1a) and formula (3-1b), Ph ３ , n3, and Cbz ３ are the same as those in formula (3-1). Hal is a halogen atom. R ０１ is a monovalent organic group.

[0094] The above method is merely an example, and the carbazole compound (C3) represented by formula (3-1) may be produced by combining various known methods as necessary.

[0095] Specific examples of suitable carbazole compounds (C3) represented by formula (3-1) described above include N-(4-phosphonophenyl)-9H-carbazole, N-(3-phosphonophenyl)-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-9H-carbazole, N-(4-phosphonophenyl)-3 -methyl-9H-carbazole, N-(4-phosphonophenyl)-3-ethyl-9H-carbazole, N-(4-phosphonophenyl)-3-fluoro-9H-carbazole, N-(4-phosphonophenyl)-3-chloro-9H-carbazole, N-(4-phosphonophenyl)-3-bromo-9H-carbazole, N-(4-phosphonophenyl)-3-iodo-9H-carbazole, N-(4-phosphonophenyl)-3,6-dimethyl-9H-carbazole, N-(4-phosphonophenyl)-3,6-diethyl-9H-carbazole, N N-(4-phosphonophenyl)-3,6-difluoro-9H-carbazole, N-(4-phosphonophenyl)-3,6-dichloro-9H-carbazole, N-(4-phosphonophenyl)-3,6-dibromo-9H-carbazole, N-(4-phosphonophenyl)-3,6-diiodo-9H-carbazole, N-(4-phosphonophenyl)-2-methyl-9H-carbazole, N-(4-phosphonophenyl)-2-ethyl-9H-carbazole, N-(4-phosphonophenyl)-2-fluoro ... N-(4-phosphonophenyl)-2-chloro-9H-carbazole, N-(4-phosphonophenyl)-2-bromo-9H-carbazole, N-(4-phosphonophenyl)-2,7-dimethyl-9H-carbazole, N-(4-phosphonophenyl)-2,7-diethyl-9H-carbazole, N-(4-phosphonophenyl)-2,7-difluoro-9H-carbazole, N-(4-phosphonophenyl)-2,7-dichloro-9H-carbazole, N-(4-phosphonophenyl)-2,7-dibromo-9H-carbazole, N-(4-phosphonophenyl)-2,7-diiodo-9H-carbazole, N-(3-phosphonophenyl)-3-methyl-9H-carbazole, N-(3-phosphonophenyl)-3-ethyl-9H-carbazole, N-(3-phosphonophenyl)-3-fluoro-9H-carbazole, N-(3-phosphonophenyl)-3-chloro-9H-carbazole, N-(3-phosphonophenyl)-3-bromo-9H-carbazole, N-(3-phosphonophenyl)- 3-iodo-9H-carbazole, N-(3-phosphonophenyl)-3,6-dimethyl-9H-carbazole, N-(3-phosphonophenyl)-3,6-diethyl-9H-carbazole, N-(3-phosphonophenyl)-3,6-difluoro-9H-carbazole, N-(3-phosphonophenyl)-3,6-dichloro-9H-carbazole, N-(3-phosphonophenyl)-3,6-dibromo-9H-carbazole, N -(3-phosphonophenyl)-3,6-diiodo-9H-carbazole, N-(3-phosphonophenyl)-2-methyl-9H-carbazole, N-(3-phosphonophenyl)-2-ethyl-9H-carbazole, N-(3-phosphonophenyl)-2-fluoro-9H-carbazole, N-(3-phosphonophenyl)-2-chloro-9H-carbazole, N-(3-phosphonophenyl)-2-bromo-9H-carbazole , N-(3-phosphonophenyl)-2,7-dimethyl-9H-carbazole, N-(3-phosphonophenyl)-2,7-diethyl-9H-carbazole, N-(3-phosphonophenyl)-2,7-difluoro-9H-carbazole, N-(3-phosphonophenyl)-2,7-dichloro-9H-carbazole, N-(3-phosphonophenyl)-2,7-dibromo-9H-carbazole, N-(3-phosphonophenyl)-2,7-diiodo-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-3-methyl-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-3-ethyl-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-3-fluoro-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-3-chloro-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-3-bromo-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-3-iodo-9H -carbazole, N-[4-(4-phosphonophenyl)phenyl]-3,6-dimethyl-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-3,6-diethyl-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-3,6-difluoro-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-3,6-dichloro-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-3,6-dibromo-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-3, 6-diiodo-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-2-methyl-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-2-ethyl-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-2-fluoro-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-2-chloro-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-2-bromo-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-2-iodo-9H -carbazole, N-[4-(4-phosphonophenyl)phenyl]-2,7-dimethyl-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-2,7-diethyl-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-2,7-difluoro-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-2,7-dichloro-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-2,7-dibromo-9H-carbazole, N-[4-(4-phosphonophenyl)phenyl]-2,7-diiodo-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-3-methyl-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-3-ethyl-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-3-fluoro-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-3-chloro-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-3-bromo-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-3-iodo-9H -carbazole, N-[3-(4-phosphonophenyl)phenyl]-3,6-dimethyl-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-3,6-diethyl-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-3,6-difluoro-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-3,6-dichloro-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-3,6-dibromo-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-3, 6-diiodo-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-2-methyl-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-2-ethyl-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-2-fluoro-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-2-chloro-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-2-bromo-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-2-iodo-9H -carbazole, N-[3-(4-phosphonophenyl)phenyl]-2,7-dimethyl-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-2,7-diethyl-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-2,7-difluoro-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-2,7-dichloro-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-2,7-dibromo-9H-carbazole, N-[3-(4-phosphonophenyl)phenyl]-2,7-diiodo-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-3-methyl-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-3-ethyl-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-3-fluoro-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-3-chloro-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-3-bromo-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-3-iodo-9H -carbazole, N-[4-(3-phosphonophenyl)phenyl]-3,6-dimethyl-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-3,6-diethyl-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-3,6-difluoro-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-3,6-dichloro-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-3,6-dibromo-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-3, 6-diiodo-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-2-methyl-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-2-ethyl-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-2-fluoro-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-2-chloro-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-2-bromo-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-2-iodo-9H -carbazole, N-[4-(3-phosphonophenyl)phenyl]-2,7-dimethyl-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-2,7-diethyl-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-2,7-difluoro-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-2,7-dichloro-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-2,7-dibromo-9H-carbazole, N-[4-(3-phosphonophenyl)phenyl]-2,7-diiodo-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-3-methyl-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-3-ethyl-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-3-fluoro-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-3-chloro-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-3-bromo-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-3-iodo Fluoro-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-3,6-dimethyl-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-3,6-diethyl-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-3,6-difluoro-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-3,6-dichloro-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-3,6-dibromo-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-3,6-dibromo-9H-carbazole, )phenyl]-3,6-diiodo-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-2-methyl-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-2-ethyl-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-2-fluoro-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-2-chloro-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-2-bromo-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-2-iodo N-[3-(3-phosphonophenyl)phenyl]-2,7-dimethyl-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-2,7-diethyl-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-2,7-difluoro-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-2,7-dichloro-9H-carbazole, N-[3-(3-phosphonophenyl)phenyl]-2,7-dibromo-9H-carbazole, and N-[3-(3-phosphonophenyl)phenyl]-2,7-diiodo-9H-carbazole is an example.

[0096] The ratio of the number of moles of the carbazole compound (C3) to the total number of moles of the compounds constituting the self-assembled monolayer III as the hole transport layer 30 is not particularly limited as long as the desired effect is not impaired. The ratio of the number of moles of the carbazole compound (C3) to the total number of moles of the compounds constituting the self-assembled monolayer III as the hole transport layer 30 is preferably 50 mol % or more, more preferably 70 mol % or more, even more preferably 90 mol % or more, and particularly preferably 100 mol %.

[0097] The self-assembled monolayer III serving as the hole transport layer 30 may contain, in addition to the carbazole compound (C3) represented by formula (3-1), a compound other than the carbazole compound (C3) represented by formula (3-1). The other compound is preferably a carbazole compound other than the carbazole compound (C3) represented by formula (3-1). The other carbazole compound preferably has a functional group such as a phosphonic acid group, a carboxy group, a sulfonic acid group, a boric acid group, a hydroxy group, an amino group, or a mercapto group. Among these, a phosphonic acid group, a carboxy group, an amino group, or a mercapto group is particularly preferred, with a phosphonic acid group or a mercapto group being even more preferred. When the carbazole compound has these functional groups, the interaction between these functional groups and the surface of the first electrode layer 20 facilitates the formation of a self-assembled monolayer serving as the hole transport layer 30.

[0098] When the self-assembled monolayer III as the hole transport layer 30 contains another carbazole compound, the other carbazole compound may be N-(2-phosphonoethyl)carbazole (2PACz), N-(2-phosphonoethyl)-3,6-dimethoxycarbazole (MeO-2PACz), N-(2-phosphonoethyl)-3,6-dimethylcarbazole (Me-2PACz), N-(2-phosphonoethyl)-2,7-dimethoxycarbazole, ... N-(3-phosphonopropyl)-2,7-dimethylcarbazole, N-(3-phosphonopropyl)carbazole (3PACz), N-(3-phosphonopropyl)-3,6-dimethoxycarbazole (MeO-3PACz), N-(3-phosphonopropyl)-3,6-dimethylcarbazole (Me-3PACz), N-(3-phosphonopropyl)-2,7-dimethoxycarbazole, N-(3-phosphonopropyl)-2,7-dimethylcarbazole, N-(4-phosphono N-(4-phosphonobutyl)-3,6-dimethoxycarbazole (MeO-4PACz), N-(4-phosphonobutyl)-3,6-dimethylcarbazole (Me-4PACz), N-(4-phosphonobutyl)-2,7-dimethoxycarbazole, N-(4-phosphonobutyl)-2,7-dimethylcarbazole, N-(4-phosphonophenyl)carbazole, N-(4-phosphonophenyl)-3,6-dimeth Preferably, the compound contains one or more selected from the group consisting of N-(4-phosphonophenyl)-3,6-dimethylcarbazole, N-(4-phosphonophenyl)-2,7-dimethoxycarbazole, and N-(4-phosphonophenyl)-2,7-dimethylcarbazole, and more preferably one or more selected from the group consisting of 2PACz, MeO-2PACz, Me-2PACz, MeO-4PACz, and Me-4PACz.

[0099] The self-assembled monolayer III serving as the hole transport layer 30 may contain, as a compound other than the carbazole compound (C3) represented by formula (3-1), n-butylphosphonic acid, n-pentylphosphonic acid, n-hexylphosphonic acid, n-octylphosphonic acid, n-decylphosphonic acid, n-octadecylphosphonic acid, 2-ethylhexylphosphonic acid, methoxymethylphosphonic acid, 3-acryloyloxypropylphosphonic acid, and 11-hydroxyundecylphosphonic acid. Phosphonic acid compounds such as 1H,1H,2H,2H-perfluorophosphonic acid, acetic acid, propionic acid, isobutyric acid, nonanoic acid, fluoroacetic acid, α-chloropropionic acid, and glyoxylic acid. These compounds may be used alone or in combination.

[0100] The self-assembled monolayer III serving as the hole transport layer 30 can be formed by applying and drying a liquid composition containing the carbazole compound (C3) represented by the aforementioned formula (3-1). The liquid composition may contain, in addition to the carbazole compound (C3) represented by formula (3-1), a compound other than the carbazole compound (C3) represented by formula (3-1). As described above, the compound other than the carbazole compound represented by formula (1) is preferably one or more selected from the group consisting of N-(2-phosphonoethyl)carbazole (2PACz), N-(2-phosphonoethyl)-3,6-dimethoxycarbazole (MeO-2PACz), and N-(4-phosphonobutyl)-3,6-dimethylcarbazole (Me-4PACz), and 2PACz and / or MeO-2PACz are more preferred.

[0101] (Self-assembled monolayer VI) The self-assembled monolayer VI is represented by the following formula (4-1): (HO) ２ P(=O)-R １ -Cbz ４ (4-1) (In formula (4-1), R １ is a divalent organic group, and Cbz ４is a 9H-carbazol-9-yl group which may be substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom. ２ -R ２ -Cbz ４ (4-2) Cbz ４ -R ２ - (S) ｎ４ -R ２ -Cbz ４ (4-3) (In formula (4-2), X ２ is a heteroatom or a heteroatom-containing group, and R ２ is a divalent hydrocarbon group, and X ２ is a heteroatom-containing group, R ２ The divalent hydrocarbon group represented by Cbz is bonded to a heteroatom in the heteroatom-containing group. ４ is Cbz in formula (4-1). ４ In formula (4-3), Cbz ４ is Cbz in formula (4-1). ４ is the same as R ２ is R in formula (4-2). ２ and n4 represents an integer of 2 to 8. A self-assembled monolayer comprising a heteroatom-containing carbazole compound represented by the following formula:

[0102] The heteroatom-containing carbazole compound represented by formula (4-2) not only constitutes the hole transport layer 30 but also exhibits a passivation effect, thereby suppressing the recombination of electrons and holes at the interface between the hole transport layer and the perovskite layer, making it possible to manufacture a perovskite solar cell with high photoelectric conversion efficiency.

[0103] In formula (4-1), R １ is a divalent organic group. The divalent organic group is not particularly limited as long as the desired effect is not impaired. The number of divalent carbon atoms is, for example, preferably 1 or more and 20 or less, more preferably 1 or more and 10 or less, even more preferably 1 or more and 6 or less, and particularly preferably 1 or more and 4 or less.

[0104] Examples of the divalent organic group include -O-, -S-, -CO-, -CO-O-, -CO-NH-, -CH=N-, -N=N-, -S-S-, and -SO ２ - and -SO ２ It may contain a heteroatom such as a bond of --O-- or a halogen atom as a substituent.

[0105] The divalent organic group is preferably a divalent hydrocarbon group. The divalent hydrocarbon group may be a chain aliphatic hydrocarbon group, a cyclic aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a combination thereof. The divalent hydrocarbon group is preferably a chain aliphatic hydrocarbon group, and more preferably a linear aliphatic hydrocarbon group. When the divalent hydrocarbon group is an aliphatic hydrocarbon group or a group containing an aliphatic hydrocarbon group, the aliphatic hydrocarbon group may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group, and is preferably a saturated aliphatic hydrocarbon group.

[0106] R １ As the divalent organic group as defined above, an alkylene group having from 1 to 6 carbon atoms or a phenylene group is particularly preferred. Examples of the alkylene group having from 1 to 6 carbon atoms include a methylene group, an ethane-1,2-diyl group (ethylene group), a propane-1,2-diyl group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, and a hexane-1,6-diyl group. The phenylene group may be any of an o-phenylene group, an m-phenylene group, and a p-phenylene group, with a p-phenylene group being preferred.

[0107] In formula (4-1), Cbz ４ is a 9H-carbazol-9-yl group which may be substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom. Hereinafter, the "9H-carbazol-9-yl group" may be referred to as a "carbazolyl group."

[0108] Cbz ４Examples of the alkyl group that may be substituted by Cbz include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, and an n-hexyl group. ４ The alkyl group which may be substituted by is preferably a methyl group or an ethyl group.

[0109] Cbz ４ Examples of the alkoxy group that may be substituted by Cbz include a methoxy group, an ethoxy group, an n-propyloxy group, an isopropyloxy group, an n-butyloxy group, an isobutyloxy group, a sec-butyloxy group, a tert-butyloxy group, an n-pentyloxy group, and an n-hexyloxy group. ４ The alkoxy group which may be substituted by is preferably a methoxy group or an ethoxy group.

[0110] Cbz ４ Examples of halogen atoms that may be substituted by Cbz include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. ４ The halogen atom which may be contained as a substituent is preferably a fluorine atom, a chlorine atom, or a bromine atom.

[0111] Cbz ４ When Cbz has one or more groups selected from an alkyl group, an alkoxy group, and a halogen atom as a substituent, the substitution position of the substituent on the carbazole ring is not particularly limited as long as the desired effect is not impaired. ４ When has the above substituents, Cbz ４ is preferably a mono-substituted carbazolyl group substituted at the 2- or 3-position, a 3,6-di-substituted carbazolyl group substituted at the 3- and 6-positions, or a 2,7-di-substituted carbazolyl group substituted at the 2- and 7-positions.

[0112] Cbz ４Specific preferred examples of the 9H-carbazol-9-yl group include a 9H-carbazol-9-yl group, a 2-methyl-9H-carbazol-9-yl group, a 2-ethyl-9H-carbazol-9-yl group, a 2-methoxy-9H-carbazol-9-yl group, a 2-ethoxy-9H-carbazol-9-yl group, a 2-fluoro-9H-carbazol-9-yl group, a 2-chloro-9H-carbazol-9-yl group, a 2-bromo-9H-carbazol-9-yl group, and a 2-iodo-9H-carbazole. -9-yl group, 3-methyl-9H-carbazol-9-yl group, 3-ethyl-9H-carbazol-9-yl group, 3-methoxy-9H-carbazol-9-yl group, 3-ethoxy-9H-carbazol-9-yl group, 3-fluoro-9H-carbazol-9-yl group, 3-chloro-9H-carbazol-9-yl group, 3-bromo-9H-carbazol-9-yl group, 3-iodo-9H-carbazol-9-yl group, 2,7-dimethyl-9H-carbazol- carbazole-9-yl group, 2,7-diethyl-9H-carbazole-9-yl group, 2,7-dimethoxy-9H-carbazole-9-yl group, 2,7-diethoxy-9H-carbazole-9-yl group, 2,7-difluoro-9H-carbazole-9-yl group, 2,7-dichloro-9H-carbazole-9-yl group, 2,7-dibromo-9H-carbazole-9-yl group, 2,7-diiodo-9H-carbazole-9-yl group, 3,6-dimethyl-9H -carbazol-9-yl group, 3,6-diethyl-9H-carbazol-9-yl group, 3,6-dimethoxy-9H-carbazol-9-yl group, 3,6-diethoxy-9H-carbazol-9-yl group, 3,6-difluoro-9H-carbazol-9-yl group, 3,6-dichloro-9H-carbazol-9-yl group, 3,6-dibromo-9H-carbazol-9-yl group, and 3,6-diiodo-9H-carbazol-9-yl group.

[0113] The phosphono group-containing carbazole compound represented by formula (4-1) described above includes N-(2-phosphonoethyl)carbazole (2PACz), N-(2-phosphonoethyl)-3,6-dimethoxycarbazole (MeO-2PACz), N-(2-phosphonoethyl)-3,6-dimethylcarbazole (Me-2PACz), N-(2-phosphonoethyl)-2,7-dimethoxycarbazole, N-(2-phosphonoethyl)-2,7-dimethylcarbazole, N-(3-phosphonopropyl)carbazole (3PACz), N-(3-phosphonopropyl)-3,6-dimethoxycarbazole (MeO-3PACz), N-(3-phosphonopropyl)-3,6-dimethylcarbazole (Me-3PACz), N-(3-phosphonopropyl)-2,7-dimethoxycarbazole, N-(3-phosphonopropyl)-2,7-dimethyl ...

[0043] Preferred is one or more selected from the group consisting of N-(4-phosphonobutyl)-2,7-dimethylcarbazole, N-(4-phosphonobutyl)carbazole (4PACz), N-(4-phosphonobutyl)-3,6-dimethoxycarbazole (MeO-4PACz), N-(4-phosphonobutyl)-3,6-dimethylcarbazole (Me-4PACz), N-(4-phosphonobutyl)-2,7-dimethoxycarbazole, N-(4-phosphonobutyl)-2,7-dimethylcarbazole, N-(4-phosphonophenyl)carbazole, N-(4-phosphonophenyl)-3,6-dimethoxycarbazole, N-(4-phosphonophenyl)-3,6-dimethylcarbazole, N-(4-phosphonophenyl)-2,7-dimethoxycarbazole, and N-(4-phosphonophenyl)-2,7-dimethylcarbazole.

[0114] Among these, N-(2-phosphonoethyl)carbazole (2PACz), N-(2-phosphonoethyl)-3,6-dimethoxycarbazole (MeO-2PACz), N-(2-phosphonoethyl)-3,6-dimethylcarbazole (Me-2PACz), N-(3-phosphonopropyl)carbazole (3PACz), N-(3-phosphonopropyl)-3,6-dimethoxycarbazole (MeO-3PACz), N-(3-phosphonopropyl)-3,6-dimethylcarbazole (Me-3PACz), N-(4-phosphonobutyl)carbazole (4PACz), N-(4-phosphonobutyl)-3,6-dimethoxycarbazole (Me

[0111] More preferred is one or more selected from the group consisting of 2PACz, MeO-2PACz, Me-2PACz, MeO-4PACz, and Me-4PACz.

[0115] Regarding the heteroatom-containing carbazole compound, R in formula (4-2) and formula (4-3) ２ The divalent hydrocarbon group as R １ In addition, Cbz in formula (4-2) and formula (4-3) is the same as the divalent hydrocarbon group. ４ is Cbz in formula (4-1). ４ is the same as:

[0116] In formula (4-2), X ２ is a heteroatom or a heteroatom-containing group. The heteroatom and the heteroatom contained in the heteroatom-containing group are not particularly limited as long as the desired effect is not impaired. ２Examples of heteroatoms include halogen atoms. As the heteroatom-containing group, a group containing one or more heteroatoms selected from the group consisting of oxygen atoms, sulfur atoms, nitrogen atoms, phosphorus atoms, and silicon atoms is preferred. As heteroatoms and heteroatoms contained in the heteroatom-containing group, atoms having lone pairs are preferred. Examples of such heteroatoms include oxygen atoms, sulfur atoms, nitrogen atoms, phosphorus atoms, and halogen atoms.

[0117] The heteroatom or heteroatom-containing group includes an amino group, —NH ２ A group represented by HY, a mercapto group, -S-S-R ３ A group selected from the group consisting of a group represented by the formula (I), an alkylthio group, an acylthio group, and a halogen atom is preferred. Y is a halogen atom. ３ is a monovalent organic group.

[0118] The amino group may be an unsubstituted amino group, a mono-substituted amino group, or a di-substituted amino group. Preferred examples of the amino group include an amino group (—NH ２ ), methylamino group, dimethylamino group, ethylamino group, diethylamino group, n-propylamino group, di-n-propylamino group, isopropylamino group, diisopropylamino group, phenylamino group, and diphenylamino group are preferred.

[0119] -NH ２ Examples of the group represented by HY include hydrofluorides of amino groups, hydrochlorides of amino groups, hydrobromides of amino groups, and hydroiodides of amino groups. Of these, hydroiodides of amino groups are preferred.

[0120] -S-S-R ３ In the group represented by ３ The monovalent organic group represented by R is preferably a hydrocarbon group. The hydrocarbon group may be a chain aliphatic hydrocarbon group, a cyclic aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a combination thereof. ３The number of carbon atoms in the hydrocarbon group as R is preferably 1 or more and 20 or less, more preferably 1 or more and 12 or less, and even more preferably 1 or more and 6 or less. When the hydrocarbon group is an aliphatic hydrocarbon group, the aliphatic hydrocarbon group may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. ３ is preferably an alkyl group or an aromatic hydrocarbon group. ３ Specific examples of the group represented by the formula include -S-S-CH ３ , -S-S-CH ２ CH ３ , -S-S-CH ２ CH ２ CH ３ , -S-S-CH(CH ３ ) ２ , and -S-S-CH ２ CH ２ CH ２ CH ３ Examples include:

[0121] The alkylthio group is preferably an alkylthio group having from 1 to 4 carbon atoms. Specific preferred examples of the alkylthio group include a methylthio group, an ethylthio group, an n-propylthio group, an isopropylthio group, and an n-butylthio group.

[0122] The acylthio group is preferably an acylthio group having from 2 to 4 carbon atoms. Specific preferred examples of the acylthio group include an acetylthio group, a propanoylthio group, and a butanoylthio group.

[0123] Halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0124] The heteroatom-containing carbazole compound represented by the formula (4-3) is a compound having a polysulfide skeleton. In the formula, n4 represents an integer of 2 to 8, preferably an integer of 2 to 5, more preferably an integer of 2 to 4, and even more preferably 2 or 3.

[0125] Preferable specific examples of the heteroatom-containing carbazole compound represented by formula (4-2) or formula (4-3) include N-(2-aminoethyl)carbazole and its hydrochloride, hydrobromide, and hydroiodide; N-(2-aminoethyl)-3,6-dimethoxycarbazole and its hydrochloride, hydrobromide, and hydroiodide; N-(2-aminoethyl)-3,6-dimethylcarbazole and its hydrochloride, hydrobromide, and hydroiodide; N-(2-aminoethyl)-2,7-dimethoxycarbazole and its hydrochloride, hydrobromide, and hydroiodide. salts, and hydroiodide salts thereof; N-(2-aminoethyl)-2,7-dimethylcarbazole, and its hydrochloride, hydrobromide, and hydroiodide salts; N-(3-aminopropyl)carbazole, and its hydrochloride, hydrobromide, and hydroiodide salts; N-(3-aminopropyl)-3,6-dimethoxycarbazole, and its hydrochloride, hydrobromide, and hydroiodide salts; N-(3-aminopropyl)-3,6-dimethylcarbazole, and its hydrochloride, hydrobromide, and hydroiodide salts; N-(3-aminopropyl)-2,7-dimethoxycarbazole N-(3-aminopropyl)-2,7-dimethylcarbazole and its hydrochloride, hydrobromide and hydroiodide salts; N-(4-aminobutyl)carbazole and its hydrochloride, hydrobromide and hydroiodide salts; N-(4-aminobutyl)-3,6-dimethoxycarbazole and its hydrochloride, hydrobromide and hydroiodide salts; N-(4-aminobutyl)-3,6-dimethylcarbazole and its hydrochloride, hydrobromide and hydroiodide salts; N-(4- N-(4-aminobutyl)-2,7-dimethoxycarbazole, and its hydrochloride, hydrobromide, and hydroiodide salts; N-(4-aminobutyl)-2,7-dimethylcarbazole, and its hydrochloride, hydrobromide, and hydroiodide salts; N-(2-mercaptoethyl)carbazole; N-(2-mercaptoethyl)-3,6-dimethoxycarbazole; N-(2-mercaptoethyl)-3,6-dimethylcarbazole; N-(2-mercaptoethyl)-2,7-dimethoxycarbazole; N-(2-mercaptoethyl)-2,7-dimethylcarbazole;N-(2-methylthioethyl)carbazole; N-(2-methylthioethyl)-3,6-dimethoxycarbazole; N-(2-methylthioethyl)-3,6-dimethylcarbazole; N-(2-methylthioethyl)-2,7-dimethoxycarbazole; N-(2-methylthioethyl)-2,7-dimethylcarbazole; N-(2-acetylthioethyl)carbazole; N-(2-acetylthioethyl)-3,6-dimethoxycarbazole; N-(2-acetylthioethyl)-3,6-dimethylcarbazole; N-(2-acetylthioethyl)-2,7-di Methoxycarbazole; N-(2-acetylthioethyl)-2,7-dimethylcarbazole; N-(3-mercaptopropyl)carbazole; N-(3-mercaptopropyl)-3,6-dimethoxycarbazole; N-(3-mercaptopropyl)-3,6-dimethylcarbazole; N-(3-mercaptopropyl)-2,7-dimethoxycarbazole; N-(3-mercaptopropyl)-2,7-dimethylcarbazole; N-(3-methylthiopropyl)carbazole; N-(3-methylthiopropyl)-3,6-dimethoxycarbazole; N-(3- N-(3-methylthiopropyl)-3,6-dimethylcarbazole; N-(3-methylthiopropyl)-2,7-dimethoxycarbazole; N-(3-methylthiopropyl)-2,7-dimethylcarbazole; N-(3-acetylthiopropyl)carbazole; N-(3-acetylthiopropyl)-3,6-dimethoxycarbazole; N-(3-acetylthiopropyl)-3,6-dimethylcarbazole; N-(3-acetylthiopropyl)-2,7-dimethoxycarbazole; N-(3-acetylthiopropyl)-2,7-dimethylcarbazole; N-(4-methylthiopropyl)-3,6-dimethylcarbazole N-(4-mercaptobutyl)carbazole; N-(4-mercaptobutyl)-3,6-dimethoxycarbazole; N-(4-mercaptobutyl)-3,6-dimethylcarbazole; N-(4-mercaptobutyl)-2,7-dimethoxycarbazole; N-(4-mercaptobutyl)-2,7-dimethylcarbazole; N-(4-methylthiobutyl)carbazole; N-(4-methylthiobutyl)-3,6-dimethoxycarbazole; N-(4-methylthiobutyl)-3,6-dimethylcarbazole; N-(4-methylthiobutyl)-2,7-dimethoxycarbazole;N-(4-methylthiobutyl)-2,7-dimethylcarbazole; N-(4-acetylthiobutyl)carbazole; N-(4-acetylthiobutyl)-3,6-dimethoxycarbazole; N-(4-acetylthiobutyl)-3,6-dimethylcarbazole; N-(4-acetylthiobutyl)-2,7-dimethoxycarbazole; N-(4-acetylthiobutyl)-2,7-dimethylcarbazole; Bis[2-(carbazol-9-yl)ethyl]disulfide; Bis[2-(3,6-dimethoxycarbazol-9-yl)ethyl]disulfide; Bis[2-(3,6-dimethylcarbazol-9-yl)ethyl]disulfide Examples of such disulfides include bis[2-(2,7-dimethoxycarbazol-9-yl)ethyl]disulfide, bis[2-(2,7-dimethylcarbazol-9-yl)ethyl]disulfide, bis[4-(carbazol-9-yl)phenyl]disulfide, bis[4-(3,6-dimethoxycarbazol-9-yl)phenyl]disulfide, bis[4-(3,6-dimethylcarbazol-9-yl)phenyl]disulfide, bis[4-(2,7-dimethoxycarbazol-9-yl)phenyl]disulfide, and bis[4-(2,7-dimethylcarbazol-9-yl)phenyl]disulfide.

[0126] Among these, N-(2-aminoethyl)carbazole hydroiodide, N-(2-aminoethyl)-3,6-dimethoxycarbazole hydroiodide, N-(2-aminoethyl)-3,6-dimethylcarbazole hydroiodide, N-(2-aminoethyl)-2,7-dimethoxycarbazole hydroiodide, N-(2-aminoethyl)-2,7-dimethylcarbazole hydroiodide, N-(2-mercaptoethyl)carbazole, N-(2-mercaptoethyl)-3,6-dimethoxycarbazole, N-(2-mercaptoethyl)-3, 6-dimethylcarbazole, N-(2-mercaptoethyl)-2,7-dimethoxycarbazole, N-(2-mercaptoethyl)-2,7-dimethylcarbazole, N-(2-acetylthioethyl)carbazole, N-(2-acetylthioethyl)-3,6-dimethoxycarbazole, N-(2-acetylthioethyl)-3,6-dimethylcarbazole, N-(2-acetylthioethyl)-2,7-dimethoxycarbazole, N-(2-acetylthioethyl)-2,7-dimethylcarbazole, N-(3-aminopropyl)carbazole hydrogen iodide acid salt, N-(3-aminopropyl)-3,6-dimethoxycarbazole hydroiodide, N-(3-aminopropyl)-3,6-dimethylcarbazole hydroiodide, N-(3-aminopropyl)-2,7-dimethoxycarbazole hydroiodide, N-(3-aminopropyl)-2,7-dimethylcarbazole hydroiodide, N-(3-mercaptopropyl)carbazole, N-(3-mercaptopropyl)-3,6-dimethoxycarbazole, N-(3-mercaptopropyl)-3,6-dimethylcarbazole, N-(3-mercaptopropyl N-(3-propyl)-2,7-dimethoxycarbazole, N-(3-mercaptopropyl)-2,7-dimethylcarbazole, N-(3-acetylthiopropyl)carbazole, N-(3-acetylthiopropyl)-3,6-dimethoxycarbazole, N-(3-acetylthiopropyl)-3,6-dimethylcarbazole, N-(3-acetylthiopropyl)-2,7-dimethoxycarbazole, N-(3-acetylthiopropyl)-2,7-dimethylcarbazole, N-(4-aminobutyl)carbazole hydroiodide, N-(4-aminobutyl)-3,6-Dimethoxycarbazole hydroiodide, N-(4-aminobutyl)-3,6-dimethylcarbazole hydroiodide, N-(4-aminobutyl)-2,7-dimethoxycarbazole hydroiodide, N-(4-aminobutyl)-2,7-dimethylcarbazole hydroiodide, N-(4-mercaptobutyl)carbazole, N-(4-mercaptobutyl)-3,6-dimethoxycarbazole, N-(4-mercaptobutyl)-3,6-dimethylcarbazole, N-(4-mercaptobutyl)-2,7-dimethoxycarbazole, N-(4-mercaptobutyl)-2,7-dimethylcarbazole, N-(4-acetylthiobutyl)carbazole, N-(4-acetylthiobutyl)-3,6-dimethoxycarbazole, N-(4-acetylthiobutyl)-3,6-dimethylcarbazole N-(4-acetylthiobutyl)-2,7-dimethoxycarbazole, and N-(4-acetylthiobutyl)-2,7-dimethylcarbazole are preferred, and N-(2-aminoethyl)carbazole hydroiodide, N-(2-mercaptoethyl)carbazole, N-(2-acetylthioethyl)carbazole, N-(3-aminopropyl)carbazole hydroiodide, N-(3-mercaptopropyl)carbazole, N-(3-acetylthiopropyl)carbazole, N-(4-aminobutyl)carbazole hydroiodide, N-(4-mercaptobutyl)carbazole, N-(4-acetylthiobutyl)carbazole, bis[(carbazol-9-yl)ethyl]disulfide, and bis[(3,6-dimethoxycarbazol-9-yl)ethyl]disulfide are more preferred.

[0127] The ratio of the number of moles of the heteroatom-containing carbazole compound represented by formula (4-2) or formula (4-3) to the total number of moles of the compounds constituting the self-assembled monolayer VI as the hole transport layer 30 is not particularly limited as long as the desired effect is not impaired. The ratio of the number of moles of the heteroatom-containing carbazole compound represented by formula (4-2) or formula (4-3) to the total number of moles of the compounds constituting the self-assembled monolayer VI as the hole transport layer 30 is preferably 0.1 mol % to 70 mol %, more preferably 0.1 mol % to 30 mol %, even more preferably 0.1 mol % to 10 mol %, still more preferably 1 mol % to 9 mol %, particularly preferably 1.5 mol % to 8 mol %, and most preferably 2 mol % to 7 mol %.

[0128] The mass ratio of the heteroatom-containing carbazole compound to the total mass of the phosphono group-containing carbazole compound and the heteroatom-containing carbazole compound is not particularly limited as long as the desired effect is not impaired. The mass ratio of the heteroatom-containing carbazole compound to the total mass of the phosphono group-containing carbazole compound and the heteroatom-containing carbazole compound is preferably 0.1 mass% or more and 70 mass% or less, more preferably 1 mass% or more and 50 mass% or less, and even more preferably 1 mass% or more and 30 mass% or less.

[0129] The self-assembled monolayer VI serving as the hole transport layer 30 may contain, as a compound other than the phosphono group-containing carbazole compound represented by formula (4-1) and the heteroatom-containing carbazole compound represented by formula (4-2) or formula (4-3), a phosphonic acid compound such as n-butylphosphonic acid, n-pentylphosphonic acid, n-hexylphosphonic acid, n-octylphosphonic acid, n-decylphosphonic acid, n-octadecylphosphonic acid, 2-ethylhexylphosphonic acid, methoxymethylphosphonic acid, 3-acryloyloxypropylphosphonic acid, 11-hydroxyundecylphosphonic acid, or 1H,1H,2H,2H-perfluorophosphonic acid, or a compound such as acetic acid, propionic acid, isobutyric acid, nonanoic acid, fluoroacetic acid, α-chloropropionic acid, or glyoxylic acid. These compounds may be used alone or in combination of two or more.

[0130] The self-assembled monolayer VI as the hole transport layer 30 can be formed by applying and drying a liquid composition for forming a self-assembled monolayer, which contains the phosphono group-containing carbazole compound represented by the above-mentioned formula (4-1) and the heteroatom-containing carbazole compound represented by formula (4-2) or formula (4-3).

[0131] (Liquid Composition for Hole Transport Layer) The liquid composition used to form the hole transport layer 30 usually contains an organic solvent. Examples of organic solvents include alcohols such as methanol, ethanol, isopropanol, and butanol; ethers such as diethyl ether, diisopropyl ether, tetrahydrofuran, 4-methyltetrahydropyran, 2-methyltetrahydrofuran, and cyclopentyl methyl ether; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; amides such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), and N-methylpyrrolidone (NMP); esters such as ethyl acetate, butyl acetate, isoamyl acetate, and γ-butyrolactone (GBL); nitriles such as acetonitrile and 3-methoxypropionitrile; aromatic compounds such as benzene, toluene, chlorobenzene, and nitrobenzene; chlorinated hydrocarbons such as dichloromethane, chloroform, and 1,2-dichloroethane; and fluorinated hydrocarbons such as chlorofluorocarbons, hydrochlorofluorocarbons, and hydrofluorocarbons.

[0132] The total concentration of the materials constituting the self-assembled monolayer contained in the liquid composition is preferably 5.0 mg / mL or less.

[0133] When a material for forming the hole transport layer 30 is contained in a perovskite precursor liquid (described later) used to form the photoelectric conversion layer 40, the hole transport layer 30 and the photoelectric conversion layer 40 can be formed simultaneously by applying the perovskite precursor liquid to the first electrode layer 20, drying the liquid, and crystallizing the perovskite precursor. In this case, the material for forming the hole transport layer 30, which is contained in the perovskite precursor liquid, forms a self-assembled monolayer on the first electrode layer 20 during the process of forming the photoelectric conversion layer 40.

[0134] A passivation layer 50 may be provided between the hole transport layer 30 and the photoelectric conversion layer 40. The passivation layer 50 between the hole transport layer 30 and the photoelectric conversion layer 40 is not shown in Fig. 1. It is preferable that the passivation layer 50 be provided between the hole transport layer 30 and the photoelectric conversion layer 40.

[0135] The material constituting the passivation layer 50 is not particularly limited as long as the desired effect is not impaired. The material constituting the passivation layer 50 can be appropriately selected from various compounds conventionally used to form passivation layers in perovskite solar cells. Suitable examples of the material constituting the passivation layer 50 include various amines or their hydrohalides. Examples of hydrohalides include hydrofluorides, hydrochlorides, hydrobromides, and hydroiodides, with hydrobromides and hydroiodides being preferred, and hydroiodides being more preferred.

[0136] Specific preferred examples of materials constituting the passivation layer 50 include n-butylamine hydrobromide, n-butylamine hydroiodide, n-hexylamine hydrobromide, n-hexylamine hydroiodide, n-decylamine hydrobromide, n-octadecylamine hydroiodide, pyridine hydrobromide, aniline hydroiodide, hydrazine dihydrobromide, ethylenediamine dihydroiodide, phenethylamine hydroiodide, 4-fluorophenethylamine hydroiodide, phenylenediamine dihydrochloride, diphenylamine hydrobromide, diphenylamine hydroiodide, benzylamine hydroiodide, and 4-diphenylaminophenethylamine hydroiodide.

[0137] Fluorine-containing amine compounds and salts thereof are also preferred materials for forming the passivation layer 50. Specific examples of suitable fluorine-containing amine compounds include compounds having a fluorinated aromatic group and an amino acid group, such as pentafluorophenylethylalanine hydroiodide, and salts thereof; fluoroalkylamines, such as 6,6,6,5,5,4,4,3,3,2,2-undecafluoropentylamine hydroiodide and 5,5,5,4,4,3,3,2,2-nonafluoropentylamine hydroiodide, and salts thereof; and compounds having a fluorinated aromatic group and an amino group, such as 4-fluorophenylethylamine hydroiodide, and salts thereof.

[0138] Among these, from the viewpoints of availability and the balance between cost and performance, an amine compound containing a fluorinated alkyl group moiety and / or a salt thereof, or a compound having a fluorinated aromatic group and an amino group is preferred, and a salt of an amine compound containing a fluorinated alkyl group is more preferred.

[0139] The passivation layer 50 between the hole transport layer 30 and the photoelectric conversion layer 40 is formed by applying a passivation layer-forming solution containing the materials constituting the passivation layer 50 and an organic solvent onto the hole transport layer 30 and drying the solution. As the organic solvent, the same solvent as that used to form the hole transport layer 30 described above can be suitably used. The application method is not particularly limited. Application can be performed using, for example, a spin coater, a die coater, a bar coater, or the like. The temperature during application is not particularly limited, but is preferably −20° C. to 200° C., and more preferably 0° C. to 150° C. The application time is not particularly limited, but is preferably 1 second to 24 hours, and more preferably 5 seconds to 1 hour.

[0140] The photoelectric conversion layer 40 contains a perovskite compound that performs photoelectric conversion and absorbs incident light to generate photocarriers. The perovskite compound contained in the photoelectric conversion layer 40 is not particularly limited as long as the desired effect is not impaired, and can be appropriately selected from well-known compounds. As a preferred example, the perovskite compound contains an organic atomic group A containing at least one of a monovalent organic ammonium ion and an amidinium-based ion, a metal atom B that generates a divalent metal ion, and a halogen atom X containing at least one of an iodide ion I, a bromide ion Br, a chloride ion Cl, and a fluoride ion F, and has a structure of ABX ３ The organic atomic group A is not particularly limited as long as the desired effect is not impaired, and can be appropriately selected from well-known organic compounds. As the organic atomic group A, methylammonium MA (CH ３ NH ３ ), Formamidinium FA (CH ３ N ２ ) etc.

[0141] The metal atom B is not particularly limited as long as it is a metal atom that has conventionally been used to form perovskite compounds. Preferred examples of the metal atom B include lead (Pb) and tin (Sn). When emphasis is placed on the power generation efficiency of the perovskite solar cell 1, it is preferable that the metal atom B be mainly lead. The lower limit of the proportion of lead in the metal atom B is preferably 50 wt %, more preferably 80 wt %, and even more preferably 90 wt %, in order to achieve the desired performance. On the other hand, when emphasis is placed on the environmental impact of lead, it is preferable that the metal atom B be mainly tin (Sn). The lower limit of the proportion of tin in the metal atom B is preferably 50 wt %, more preferably 80 wt %, and particularly preferably 90 wt %, in order to achieve the desired performance.

[0142] The halogen atom is not particularly limited. The halogen atom X is preferably at least one of iodide I, bromide Br, and chloride Cl. Furthermore, substituting a part or all of the organic atomic group A with an alkali metal Am has also been considered, and such a perovskite compound can also be used. The alkali metal Am is not particularly limited. Examples of preferred alkali metals Am include potassium K, cesium Cs, and rubidium Rb. Among these, when emphasis is placed on the durability and water resistance of the perovskite solar cell 1, cesium Cs and rubidium Rb are preferred as the alkali metal Am, and cesium Cs is particularly preferred from the standpoints of cost and availability.

[0143] Specifically, preferred perovskite compounds include, for example, MAPbI ３ , MAPbBr ３ , MAPbCl ３ Methylammonium lead halides (MAPbX) such as ３ ), and FAPbI ３ , FAPbBr ３ , FAPbCl ３ Formamidinium lead halide (FAPbX) ３ The halogen atom X may contain multiple types, and the organic atomic group A may be FA containing both methylammonium and formamidinium. ｙ MA １－ｙ PbX ３ In addition, when the alkali metal Am is contained, Am ｙ FA ｚ MA １－ｙ－ｚ PbIX, Am ｙ FA １－ｙ Am may be a single type of Cs, Rb, or K, or may contain a plurality of types of Am (where y and z are any positive integers).

[0144] The passivation layer 50 provided between the photoelectric conversion layer 40 and the electron transport layer 60 prevents the recombination of photocarriers at the interface between the photoelectric conversion layer 40 and the electron transport layer 60, and promotes the arrival of electrons at the electron transport layer 60.

[0145] The material constituting the passivation layer 50 provided between the photoelectric conversion layer 40 and the electron transport layer 60 can be the same as the material constituting the passivation layer 50 provided between the hole transport layer 30 and the photoelectric conversion layer 40. The material constituting the passivation layer 50 provided between the photoelectric conversion layer 40 and the electron transport layer 60 is preferably the above-mentioned hydrohalide salt of an amine, an amine having a fluorinated alkyl group, or a hydrohalide salt thereof.

[0146] The desired effect can be achieved even if the material constituting the passivation layer 50 is an amine compound rather than a hydrohalide salt as described above. In this case, the amine compound interacts with lead ions and the like that form the perovskite crystal through the unshared electron pairs on the nitrogen atoms, thereby preventing charge recombination.

[0147] The passivation layer 50 provided between the photoelectric conversion layer 40 and the electron transport layer 60 can be formed, similarly to the passivation layer 50 provided between the hole transport layer 30 and the photoelectric conversion layer 40, by applying a passivation layer forming solution containing the material constituting the passivation layer 50 and an organic solvent onto the photoelectric conversion layer 40 and drying the solution.

[0148] When the perovskite precursor liquid used to form the photoelectric conversion layer 40 contains a material that constitutes the passivation layer 50, the perovskite precursor liquid is applied to the hole transport layer 30, dried, and the perovskite precursor is crystallized, thereby forming the passivation layer 50 on both main surfaces of the photoelectric conversion layer 40. In this case, in the process of forming the photoelectric conversion layer 40, the material that constitutes the passivation layer 50, which is contained in the perovskite precursor liquid, is precipitated on both main surfaces of the photoelectric conversion layer 40, and the passivation layer 50 is formed.

[0149] Furthermore, when the perovskite precursor liquid used to form the photoelectric conversion layer 40 contains a material for forming the hole transport layer 30 and a material for forming the passivation layer 50, the perovskite precursor liquid is applied to the first electrode layer 20, dried, and the perovskite precursor is crystallized, thereby simultaneously forming the hole transport layer 30, the passivation layer 50 (not shown in FIG. 1 ), the photoelectric conversion layer 40, and the passivation layer 50 in this order on the first electrode layer 20. In this case, during the process of forming the photoelectric conversion layer 40, the material for forming the hole transport layer 30 contained in the perovskite precursor liquid forms a self-assembled monolayer on the first electrode layer 20. Furthermore, the material for forming the passivation layer 50 contained in the perovskite precursor liquid is precipitated on both main surfaces of the photoelectric conversion layer 40, thereby forming the passivation layer 50.

[0150] When the perovskite precursor liquid contains a material that constitutes the passivation layer 50 and a perovskite precursor, fluorine-containing amine compounds and salts thereof are preferred as materials that constitute the passivation layer 50 because they are easily precipitated at the interface or surface of the perovskite polycrystal by utilizing the hydrophobic interaction of fluorine atoms. The content of fluorine atoms in the fluorine-containing amine compound is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, in terms of the mass of fluorine atoms in the molecular weight of each compound. When the fluorine-containing amine compound and salts thereof contain fluorine atoms in the above ratio, the fluorine-containing amine compound is easily precipitated on the perovskite crystal surface by sufficient hydrophobic interaction.

[0151] The electron transport layer 60 effectively transmits electrons and transfers them to the second electrode layer 70. The material constituting the electron transport layer 60 is not particularly limited as long as the desired effect is not impaired. The material constituting the electron transport layer 60 can be appropriately selected from various compounds conventionally used to form electron transport layers in perovskite solar cells. The electron transport layer 60 is preferably formed from a material mainly composed of, for example, fullerene or naphthalene diimide. Examples of fullerenes include C60, C70, and their hydrides, oxides, metal complexes, and derivatives with alkyl groups added thereto, such as PCBM ([6,6]-Phenyl-C61-Butyric Acid Methyl Ester). Furthermore, a hole-blocking layer such as pasocuproine (BCP), lithium fluoride (LiF), or magnesium fluoride (MgF) may be provided between the electron transport layer 60 and the second electrode layer 70. ２ ), tin oxide (SnO ２ ), aluminum-doped zinc oxide (ZnO), titanium oxide (TiO ２ The inorganic oxide layer may be doped with another metal material. The hole blocking layer material is not limited to these.

[0152] When the perovskite solar cell 1 receives light from the side of the substrate 10, the second electrode layer 70 preferably includes a metal layer made of, for example, copper in order to reduce electrical resistance. The metal constituting the metal layer is not limited to copper. Furthermore, when the perovskite solar cell 1 receives light from the side of the second electrode layer 70, the second electrode layer 70 may be made of a transparent conductive oxide.

[0153] The perovskite solar cell 1 having the above configuration can be manufactured by an embodiment of a solar cell manufacturing method shown in FIG. 2 . The solar cell manufacturing method of this embodiment includes a first electrode layer forming step (step S11), a hole transport layer forming step (step S12), a precursor liquid application step (step S13), a crystallization step (step S14), an electron transport layer forming step (step S15), and a second electrode layer forming step (step S16). The embodiment of the solar cell manufacturing method shown in FIG. 2 may include a first passivation layer forming step (step S01, not shown in FIG. 2 ) between the hole transport layer forming step (step S12) and the precursor liquid application step (step S13). Furthermore, when a precursor liquid not containing a material constituting the passivation layer 50 is used in the precursor liquid application step (step S13), the embodiment of the solar cell manufacturing method shown in FIG. 2 may also include a second passivation layer forming step (step S02, not shown in FIG. 2 ).

[0154] In the first electrode layer formation process of step S11, a first electrode layer 20 is formed on one main surface of the substrate 10. The first electrode layer 20 can be deposited using a vacuum film-forming technique such as sputtering. In the first electrode layer process, it is preferable to modify the surface of the deposited first electrode layer 20 to facilitate the formation of the hole transport layer 30 in the next process. Specific methods for modifying the surface of the first electrode layer 20 include, for example, surface hydroxylation by ultraviolet-ozone treatment or ozone water washing, film formation by a vacuum film-forming technique such as sputtering of an oxide such as nickel oxide, which is prone to grow a self-assembled film, film formation by a coating technique of oxide nanoparticles, and heat treatment to activate the surface to facilitate the growth of a self-assembled film and remove impurities.

[0155] In the hole transport layer formation step of step S12, the hole transport layer 30 is laminated on the first electrode layer 20. The hole transport layer 30 can be formed by a method such as coating a solution containing the material that constitutes the hole transport layer 30 and an organic solvent, followed by drying. The drying temperature is, for example, preferably 50°C or higher, more preferably 80°C or higher, and even more preferably 100°C or higher. The drying time is preferably 1 minute or longer, more preferably 5 minutes or longer, and even more preferably 10 minutes or longer. When drying is performed under the above conditions, the organic solvent is sufficiently removed from the coating film, making it easier to obtain the desired crystals in the subsequent step of forming perovskite polycrystals.

[0156] After forming the hole transport layer 30 in step S12, a first passivation layer forming step (step S01) may be performed as necessary to form a passivation layer 50 on the hole transport layer 30. In the first passivation layer forming step (step S01), a passivation layer forming solution containing a material that constitutes the passivation layer 50 and an organic solvent is applied onto the hole transport layer 30, and then the applied film is dried, thereby forming the passivation layer 50 on the hole transport layer 30.

[0157] The passivation layer forming solution can be applied using, for example, a spin coater, a die coater, or a bar coater.

[0158] In the precursor liquid application step of step S13, the perovskite precursor liquid is applied to the laminate of the substrate 10, the first electrode layer 20, and the hole transport layer 30. When step S01 is performed, the perovskite precursor liquid is applied to the passivation layer 50 formed on the hole transport layer 30. The perovskite precursor liquid can be applied using, for example, a spin coater, a die coater, a bar coater, or the like.

[0159] The perovskite precursor liquid contains an organic solvent and a perovskite precursor that forms a perovskite compound that performs photoelectric conversion. The perovskite precursor liquid may further contain a hydrochloride that promotes crystal growth of the perovskite compound.

[0160] The perovskite precursor liquid may contain a material that constitutes the hole transport layer 30. In this case, step S12 of forming the hole transport layer 30 may be omitted. This is because the hole transport layer 30 is formed in the process of forming the photoelectric conversion layer 40 in steps S13 and S14.

[0161] The perovskite precursor liquid may contain a material that forms the passivation layer 50. In this case, the passivation layer 50 is formed on both main surfaces of the photoelectric conversion layer 40 in the process of forming the photoelectric conversion layer 40 in steps S13 and S14.

[0162] The perovskite precursor contained in the perovskite precursor liquid is as described above.

[0163] Examples of organic solvents include amide solvents such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), and N-methylpyrrolidone (NMP); sulfoxides such as dimethyl sulfoxide (DMSO), diethyl sulfoxide, and dibutyl sulfoxide; esters such as ethyl acetate, butyl acetate, amyl acetate, and γ-valerolactone (GBL); and aprotic polar solvents such as acetonitrile. These solvents may be used alone or in combination, and may further contain other types of organic solvents. The boiling points of these organic solvents are preferably as low as possible because they must be distilled off during the formation of perovskite crystals. Specifically, the boiling point under atmospheric pressure is preferably 300°C or lower, more preferably 200°C or lower, and even more preferably 180°C or lower. When an organic solvent having such a boiling point is used, the organic solvent is less likely to remain in the perovskite crystals, facilitating the production of a perovskite solar cell 1 with the desired performance. The concentration of the perovskite precursor solution is related to the conditions of the crystallization process. The solids concentration of the perovskite precursor solution is preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more. When the solids concentration of the perovskite precursor solution is within this range, the organic solvent can be volatilized with less energy when forming the photoelectric conversion layer 40, and the perovskite solar cell 1 can be produced at low cost while reducing the environmental impact.

[0164] The perovskite precursor contains a metal halide BX and at least one of a halogenated organic compound AX and an alkali metal halide AmX in a predetermined ratio. Lead halide is preferably used as the metal halide BX. Formamidine hydrohalide and methylamine hydrohalide are preferably used as the halogenated organic compound AX, and cesium iodide is preferably used as the alkali metal halide AmX. The molar concentration of the metal atom B is preferably 0.5 mol% or more and 10 mol% or less in excess of the sum of the molar concentration of the organic compound and the molar concentration of the alkali metal Am. This expels other materials to the front and back interfaces of the perovskite precursor liquid during the crystallization process, thereby preventing a decrease in photoelectric conversion efficiency due to other materials remaining in the perovskite crystal.

[0165] When the perovskite precursor solution contains a material for forming a passivation film, the material for forming the passivation film aggregates in the form of a film on the surface of the coating of the perovskite precursor liquid. As a result, the material for forming the passivation film covers the surface of the layer of perovskite compound (photoelectric conversion layer 40) generated from the perovskite precursor, thereby forming a passivation layer 50 that suppresses recombination of photocarriers (holes and electrons) at the interface of the photoelectric conversion layer 40.

[0166] The hydrochloride promotes the crystallization of the perovskite compound and increases the grain size of the perovskite crystals. This reduces the area of ​​the grain boundaries in the photoelectric conversion layer 40 and suppresses a decrease in photoelectric conversion efficiency due to impurities between the perovskite crystals. Examples of hydrochlorides include methylammonium hydrochloride (MACl), formamidinium hydrochloride (FACl), and methylenediaminium hydrochloride (MDACl). ２ The moiety other than the hydrochloride salt preferably has a size equal to or smaller than the crystal lattice of the perovskite crystal and has an amino group. The concentration of the hydrochloride salt in the perovskite precursor liquid may be 1 mol % or more and 40 mol % or less relative to the molar concentration of the ions of the metal atom B in the perovskite compound.

[0167] In the crystallization step of step S14, the perovskite precursor liquid film is dried (the solvent is evaporated), causing the perovskite precursor to react and generate crystals of the perovskite compound. This forms a photoelectric conversion layer 40 mainly composed of the perovskite compound. If the perovskite precursor solution contains a material that forms a passivation film, the photoelectric conversion layer 40 is formed and the passivation layer 50 is fixed. Methods for promoting the generation of crystals of the perovskite compound in the perovskite precursor liquid film include, for example, poor solvent quenching, vacuum quenching, gas quenching, laser treatment, and the like. In the crystallization step of step S14, the dried coating film of the perovskite precursor liquid may be further heated.

[0168] After forming the photoelectric conversion layer 40 in steps S13 and S14, a second passivation layer forming step (step S02) may be performed as necessary to form a passivation layer 50 on the main surface of the photoelectric conversion layer 40 opposite the hole transport layer 30. In the second passivation layer forming step (step S02), a passivation layer forming solution containing a material constituting the passivation layer 50 and an organic solvent is applied onto the photoelectric conversion layer 40, and then the applied film is dried to form the passivation layer 50 on the photoelectric conversion layer 4030.

[0169] In the electron transport layer forming step S15, the electron transport layer 60 is formed by a method such as coating or vacuum deposition. A hole blocking layer may be formed on the electron transport layer 60 by vacuum deposition or atomic deposition.

[0170] In the second electrode layer forming step S16, the second electrode layer 70 is formed by a method such as sputtering, vacuum deposition, plating, or coating depending on the forming material.

[0171] The perovskite solar cell described above exhibits high photoelectric conversion efficiency.

[0172] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and various modifications and variations are possible. The solar cell according to the present invention may include an additional functional layer. For example, the electron transport layer may be omitted in the perovskite solar cell. Furthermore, the perovskite solar cell may be a tandem solar cell that uses a photoelectric converter such as a crystalline silicon solar cell as a substrate.

[0173] The present invention will be specifically described below based on examples, but the present invention is not limited to the following examples.

[0174] <Example 1-1> (Step 1) Synthesis of PEA-2 In a reaction vessel, 2.02 g of tyramine and 10 mg of dimethylaminopyridine were dissolved in 20 mL of tetrahydrofuran (THF). The resulting solution was stirred at room temperature while di-tert-butyl dicarbonate ((Boc) ２ 15 mL of a tetrahydrofuran solution containing 3.37 g of methyl 2-(2-hydroxybenzoic acid) was dropped into the reaction vessel. The reaction solution in the reaction vessel was stirred at room temperature for 2 days, and then the THF was distilled off under reduced pressure. The resulting residue was dissolved in dichloromethane. The dichloromethane solution was washed with 1 M hydrochloric acid, pure water, and saturated saline. Thereafter, the dichloromethane solution was dried over magnesium sulfate. Next, the dichloromethane was distilled off under reduced pressure to obtain PEA-2 (3.53 g) as a pale yellow solid. １ The results of H-NMR measurement were as follows: １ H-NMR (400MHz, CDCl ３ ): δ = 7.05 (m, 2H), 6.80 (m, 2H), 3.36 (m, 2H), 2.73 (m, 2H), 1.46 (s, 9H)

[0175] (Step 2) Synthesis of PEA-3 1.00 g of PEA-2, 1.10 g of 3-bromopropyl diethyl phosphate, 1.17 g of potassium carbonate, and sodium iodide (20 mg) were added to 5 mL of N,N-dimethylformamide (DMF) in a reaction vessel. The reaction mixture was stirred at room temperature for 3 days, and then filtered through Celite. DMF was then distilled off from the obtained filtrate under reduced pressure. The obtained residue was dissolved in dichloromethane, and the dichloromethane solution was washed with pure water and saturated saline. After drying the dichloromethane solution over magnesium sulfate, dichloromethane was distilled off under reduced pressure. The product obtained as a residue was purified by silica gel column chromatography to obtain PEA-3 (1.86 g) as a pale yellow liquid. The obtained compound PEA-3 １ H-NMR was as follows: １ H-NMR (400MHz, CDCl ３ ): δ = 7.11 (m, 2H), 6.84 (m, 2H), 4.12 (t, 4H), 4.00 (t, 2H), 3.75 (m, 2H), 2.74 (t, 2H), 2.10 (m, 2H), 1.95 (m, 2H), 1.45 (s, 9H), 1.34 (t, 6H)

[0176] (Step 3) Synthesis of PEA-4 0.517 g of PEA-3 was dissolved in 5 mL of 1,4-dioxane in a reaction vessel. While the resulting solution was stirred at room temperature, 1.6 mL of trimethylsilyl bromide was added dropwise to the reaction vessel. The reaction mixture was stirred at room temperature for 3 days, and then volatiles were distilled off from the reaction mixture under reduced pressure. 3 mL of methanol and 5 mL of pure water were added to the pale yellow liquid obtained as a residue, and the resulting mixture was stirred at room temperature overnight. Thereafter, the resulting precipitate was collected by filtration. The resulting precipitate was washed with pure water and then dried under reduced pressure to obtain PEA-4 (0.220 g) as a white solid. The resulting compound PEA-4 １ H-NMR was as follows: １ H-NMR (400MHz, MeOH-d ４ ): δ = 7.19 (m, 2H), 6.93 (m, 2H), 4.05 (t, 2H), 3.15 (m, 2H), 2.90 (t, 2H), 2.05 (m, 2H), 1.80 (m, 2H)

[0177] <Example 1-2>

[0178] (Step 1) Synthesis of PEA-7 2.55 g of PEA-2, 2.14 g of 1-bromo-6-chlorohexane, 1.65 g of potassium carbonate, and sodium iodide (20 mg) were added to 22 mL of N,N-dimethylformamide (DMF) in a reaction vessel. The reaction mixture was stirred at room temperature for 42 hours, and then reacted at 120°C for an additional 2.5 hours. The reaction mixture was then filtered through Celite. DMF was then distilled off from the resulting filtrate under reduced pressure. The resulting residue was dissolved in dichloromethane, and the dichloromethane solution was washed with pure water and saturated saline. The dichloromethane solution was then dried over magnesium sulfate, and the dichloromethane was distilled off under reduced pressure. The product obtained as a residue was purified by silica gel column chromatography to obtain PEA-5 (0.758 g) as a white solid. １ H-NMR was as follows: １ H-NMR (400MHz, CDCl ３ ): δ = 7.09 (d, 2H), 6.83 (d, 2H), 3.94 (t, 2H), 3.55 (t, 2H), 3.33 (m, 2H), 2.73 (t, 2H), 1.86-1.64 (m, 4H), 1.54-1.46 (m, 4H), 1.43 (s, 9H)

[0179] (Step 2) Synthesis of PEA-6 0.225 g of PEA-5 was dissolved in 2.71 g of triethyl phosphite. The resulting solution was stirred at 160°C for 2 days. Volatile matter was distilled off from the reaction mixture under reduced pressure. The product obtained as a residue was purified by silica gel column chromatography to obtain PEA-6 (0.276 g) as a colorless, transparent liquid. １ H-NMR was as follows: １ H-NMR (400MHz, CDCl ３ ): δ = 7.09 (d, 2H), 6.83 (d, 2H), 4.09 (m, 4H), 3.93 (t, 2H), 3.33 (m, 2H), 2.73 (t, 2H), 1.88-1.55 (m, 6H), 1.55-1.37 (m, 13H), 1.32 (t, 6H)

[0180] (Step 3) Synthesis of PEA-7 0.276 g of PEA-6 was dissolved in 6.75 g of dichloromethane in a reaction vessel. While the obtained solution was stirred at room temperature, 1.90 g of trimethylsilyl bromide was added dropwise to the reaction vessel. The reaction mixture was stirred at room temperature for 3 days, and then volatiles were distilled off from the reaction mixture under reduced pressure. 1 mL of methanol and 2.0 mL of pure water were added to the pale yellow liquid obtained as the residue, and the resulting mixture was stirred at room temperature. Thereafter, the resulting precipitate was collected by filtration. The obtained precipitate was washed with pure water and then dried under reduced pressure to obtain PEA-7 (0.050 g) as a white solid. The obtained compound PEA-7 １ H-NMR was as follows: １ H-NMR (400MHz, MeOH-d ４ ): δ = 7.21 (d, 2H), 6.89 (d, 2H), 3.97 (t, 2H), 3.14 (t, 2H), 2.92 (t, 2H), 1.83-1.40 (m, 10H)

[0181] <Example 1-3>

[0182] (Step 1) Synthesis of PEA-8 2.34 g of PEA-2, 2.96 g of 1,10-dibromodecane, 1.51 g of potassium carbonate, and sodium iodide (20 mg) were added to 25 mL of N,N-dimethylformamide (DMF) in a reaction vessel. The reaction mixture was stirred at room temperature for 1 day, and then filtered through Celite. DMF was then distilled off from the obtained filtrate under reduced pressure. The obtained residue was dissolved in dichloromethane, and the dichloromethane solution was washed with pure water and saturated saline. After drying the dichloromethane solution over magnesium sulfate, dichloromethane was distilled off under reduced pressure. The product obtained as a residue was purified by silica gel column chromatography to obtain PEA-8 (0.930 g) as a white solid. The obtained compound PEA-8 １ H-NMR was as follows: １ H-NMR (400MHz, CDCl ３): δ = 7.10 (d, 2H), 6.83 (d, 2H), 3.93 (t, 2H), 3.41 (t, 2H), 3.34 (m, 2H), 2.72 (t, 2H), 1.88-1.73 (m, 4H), 1.52-1.23 (m, 21H)

[0183] (Step 2) Synthesis of PEA-9 0.202 g of PEA-8 was dissolved in 1.97 g of triethyl phosphite. The resulting solution was stirred at 160°C overnight. Volatile matter was distilled off from the reaction mixture under reduced pressure. The product obtained as a residue was purified by silica gel column chromatography to obtain PEA-9 (0.156 g) as a pale brown liquid. １ H-NMR was as follows: １ H-NMR (400MHz, CDCl ３ ): δ = 7.08 (d, 2H), 6.83 (d, 2H), 4.09 (m, 4H), 3.93 (t, 2H), 3.33 (m, 2H), 2.73 (t, 2H), 1.82-1.65 (m, 4H), 1.52-1.23 (m, 27H)

[0184] (Step 3) Synthesis of PEA-10 0.066 g of PEA-9 was dissolved in 2 mL of dichloromethane in a reaction vessel. While the obtained solution was stirred at room temperature, 1.50 mL of trimethylsilyl bromide was added dropwise to the reaction vessel. The reaction mixture was stirred overnight at room temperature, and then volatiles were distilled off from the reaction mixture under reduced pressure. 3 mL of methanol and 1.5 mL of pure water were added to the pale yellow liquid obtained as the residue, and the resulting mixture was stirred at room temperature. Thereafter, the resulting precipitate was collected by filtration. The obtained precipitate was washed with pure water and then dried under reduced pressure to obtain PEA-10 (0.047 g) as a white solid. １ H-NMR was as follows: １ H-NMR (400MHz, MeOH-d ４ ): δ = 7.18 (d, 2H), 6.89 (d, 2H), 3.96 (t, 2H), 3.12 (m, 2H), 2.89 (t, 2H), 1.85-1.55 (m, 4H), 1.55-1.20 (m, 14H)

[0185] Next, the cell performance was evaluated using PEA-4, PEA-7, and PEA-10.

[0186] Example 1-4 First, a NiOx film was formed on the FTO layer of a commercially available glass / FTO substrate. The glass / FTO substrate was a substrate in which FTO, which constituted the first electrode layer, had been pre-laminated on a glass substrate. Next, a solution of a material for forming a hole transport layer dissolved in ethanol at a concentration of 1.0 mg / mL was spin-coated onto the NiOx layer. The materials used for forming the hole transport layer were 2PACz, MeO-2PACz, and 2-[4-(3-phosphonopropyloxy)phenyl]ethylamine obtained in Example 1-1. The molar ratio of 2PACz, MeO-2PACz, and 2-[4-(3-phosphonopropyloxy)phenyl]ethylamine was 47.5:47.5:5. That is, a material for forming a hole transport layer containing 5 mol % of 2-[4-(3-phosphonopropyloxy)phenyl]ethylamine was used. The coating film formed by spin coating was dried at 100°C for 10 minutes to form a hole transport layer. A solution in which 4-fluorophenylethylamine hydroiodide was dissolved in DMF at a concentration of 80 mM was spin coated onto the hole transport layer. The coating film formed by spin coating was dried at 100°C for 5 minutes to form a passivation layer. A perovskite precursor solution in which a perovskite precursor was dissolved at a concentration of 3.2 M in a mixed solvent of DMSO and DMF at a volume ratio of 1:4 was spin coated onto the passivation layer. PbI was used as the perovskite precursor. ２A mixture of (metal halide) and FAI and MABr (halogenated organic compound) in a molar ratio of 1:0.83:0.17 was used. The spin-coated coating film was heated at 120°C for 30 minutes to form a photoelectric conversion layer. A solution of 1H,1H-undecafluorohexylamine hydroiodide dissolved in 2-propanol at a concentration of 0.25 mmol / L was spin-coated onto the photoelectric conversion layer. The spin-coated coating film was dried at 100°C for 10 minutes to form a passivation layer. Further, fullerene was vapor-deposited to a thickness of 20 nm as an electron transport layer, followed by the formation of a 220 nm-thick SnO thin film as a buffer layer by atomic deposition. Silver was then vapor-deposited to a thickness of 100 nm, and a second electrode layer was laminated on the passivation layer to obtain a perovskite solar cell.

[0187] <Example 1-5> A perovskite solar cell was obtained in the same manner as in Example 1-4, except that the molar ratio of 2PACz, MeO-2PACz, and 2-[4-(3-phosphonopropyloxy)phenyl]ethylamine in the materials for forming the hole transport layer was changed from 47.5:47.5:5 to 25:25:50.

[0188] Examples 1-6 and 1-7 In Example 1-6, a perovskite solar cell was obtained in the same manner as in Example 1-4, except that the 2-[4-(3-phosphonopropyloxy)phenyl]ethylamine in Example 1-4 was changed to PEA-7 synthesized in Example 1-2. In Example 1-7, a perovskite solar cell was obtained in the same manner as in Example 1-4, except that the 2-[4-(3-phosphonopropyloxy)phenyl]ethylamine in Example 1-4 was changed to PEA-10 synthesized in Example 1-3.

[0189] Comparative Example 1-1 A perovskite solar cell was obtained in the same manner as in Example 1-4, except that the material for forming the hole transport layer was changed to an equimolar mixture of 2PACz and MeO-2PACz.

[0190] The results of measuring the IV characteristics of the obtained perovskite solar cells of Examples 1-4 to 1-7 and Comparative Example 1-1 are shown in Table 1 below.

[0191]

[0192] Table 1 shows that the perovskite solar cells of the examples, in which the hole transport layer contains the phenethylamine compound represented by formula (1-1) above, have superior photoelectric conversion efficiency to the perovskite solar cells of the comparative examples, in which the hole transport layer does not contain the phenethylamine compound represented by formula (1-1) above.

[0193] Example 2-1: Synthesis of SAM2-1 Diethyl phosphite (2.28 mL) was added to a mixture of 5.02 g of 4,4'-dibromobiphenyl, palladium acetate (0.108 g), triphenylphosphine (0.379 g), triethylamine (3.35 mL), and ethanol (40 mL) that was being stirred at room temperature under a nitrogen atmosphere. The reaction mixture was then stirred at 80°C for 24 hours. The volatile matter was then distilled off under reduced pressure. Ethyl acetate was added to the resulting residue, and the ethyl acetate solution was washed with purified water, 1 M hydrochloric acid, a saturated aqueous solution of sodium bicarbonate, and saturated saline. The solution was then dried over magnesium sulfate. The volatile matter was distilled off under reduced pressure, and a brown liquid reaction mixture was obtained as a residue. The reaction mixture was purified by silica gel column chromatography to obtain Compound A-1 as a light brown liquid. The resulting Compound A-1 １ H-NMR was as follows: １ H-NMR (400MHz, CDCl ３ ): δ = 7.88 (m, 2H), 7.64 (m, 2H), 7.60 (m, 2H), 7.47 (m, 2H), 4.13 (m, 4H), 1.35 (t, 6H)

[0194] Next, tri-tert-butylphosphine (30 μL) was added to a mixture of compound A-1 (0.710 g), 3,6-dimethylcarbazole (0.460 g), palladium acetate (0.015 g), potassium carbonate (0.797 g), and 10 mL of xylene, which was being stirred at room temperature under a nitrogen atmosphere. The reaction mixture was then stirred at 120° C. for 22 hours. Thereafter, the reaction mixture was filtered using Celite. Volatiles were removed from the obtained filtrate by distillation under reduced pressure. The crude product obtained as a residue was purified by silica gel column chromatography to obtain compound A-2 as a light brown solid. The obtained compound A-2 １ H-NMR was as follows: １ H-NMR (400MHz, CDCl ３ ): δ = 7.94 (m, 2H), 7.82-7.75 (m, 4H), 7.65 (m, 2H), 7.56 (d, 2H), 7.47 (d, 2H), 7.06 (dd, 2H), 4.17 (m, 4H), 3.96 (s, 6H), 1.37 (t, 6H)

[0195] Next, compound A-2 (0.191 g) was dissolved in 2 mL of 1,4-dioxane. To the solution of compound A-2 being stirred at room temperature, 0.50 mL of trimethylsilyl bromide was added, and the mixture was stirred at room temperature for 24 hours. Then, the volatile matter was distilled off under reduced pressure. The crude product obtained as the residue was mixed with 2.0 mL of methanol and 2.5 mL of pure water, and the mixture was stirred at room temperature for 24 hours. Then, the precipitate was filtered and washed three times with 2 mL of pure water. The volatile matter was distilled off under vacuum at 65°C, yielding SAM2-1 as a pale green solid. The obtained compound SAM2-1 １ H-NMR was as follows: １ H-NMR (400MHz, DMSO-d ６ ): δ = 7.97 (d, 2H), 7.88-7.75 (m, 6H), 7.71 (d, 2H), 7.39 (d, 2H), 7.05 (dd, 2H), 3.88 (s, 6H)

[0196] Example 2-2: Synthesis of SAM2-2 To a mixture of 3-bromocarbazole (3.03 g), copper iodide (7.11 g), and DMF (49 mL) stirred at room temperature under a nitrogen atmosphere, 5 M sodium methoxide (methanol solution, 49 mL) was added. The reaction mixture was then stirred at 120°C for 27 hours. After the reaction mixture was cooled to room temperature, pure water was added to the reaction mixture. The product in the pure water was then extracted five times with ethyl acetate. The organic phase was washed with pure water and saturated brine and dried over anhydrous magnesium sulfate. Volatiles were then distilled off under reduced pressure. The crude product obtained as a residue was purified by silica gel column chromatography to obtain Compound A-3 as a light brown solid. The obtained Compound A-3 １ H-NMR was as follows: １ H-NMR (400MHz, CDCl ３ ): δ = 8.03 (d, 1H), 7.91 (brs, 1H), 7.56 (d, 1H), 7.41-7.39 (m, 2H), 7.33 (d, 1H), 7.24-7.16 (m, 1H), 7.06 (dd, 1H), 3.93 (s, 3H)

[0197] Next, tri-tert-butylphosphine (40 μL) was added to a mixture of diethyl (4-bromophenyl)phosphonate (0.708 g), Compound A-3 (0.500 g), palladium acetate (0.019 g), potassium carbonate (1.01 g), and 10 mL of xylene, which was stirred at room temperature under a nitrogen atmosphere. The reaction mixture was stirred at 120°C for 29 hours. Thereafter, the reaction mixture was filtered using Celite. Volatiles were distilled off from the obtained filtrate under reduced pressure. The crude product obtained as a residue was purified by silica gel column chromatography to obtain Compound A-4 as a pale brown liquid. The obtained Compound A-4 １ H-NMR was as follows: １ H-NMR (400MHz, CDCl ３ ): δ = 8.12-8.00 (m, 3H), 7.70 (m, 2H), 7.60 (d, 1H), 7.48 (d, 1H), 7.40 (d, 2H) ), 7.32-7.26 (m, 1H), 7.06 (dd, 1H), 4.26 (m, 4H), 3.95 (s, 3H), 1.40 (t, 6H)

[0198] Next, compound A-4 (0.485 g) was dissolved in 3 mL of 1,4-dioxane. To the solution of compound A-4 being stirred at room temperature, 1.60 mL of trimethylsilyl bromide was added, and the mixture was stirred at room temperature for 20 hours. Then, the volatile matter was distilled off under reduced pressure. The crude product obtained was mixed with 3.0 mL of methanol and 3.5 mL of pure water, and the mixture was stirred at room temperature for 20 minutes. Then, the precipitate was filtered and washed three times with 2 mL of pure water. The volatile matter was distilled off under vacuum at 65°C, yielding SAM2-2 as a white solid. １ H-NMR was as follows: １ H-NMR (400MHz, DMSO-d ６ ): δ = 8.26 (d, 1H), 7.95 (m, 2H), 7.84 (d, 1H), 7.73 (dd, 2H), 7.50-7.37 (m, 3H), 7.28 (td, 1H), 7.07 (dd, 1H), 3.89 (s, 3H)

[0199] Next, the performance of the cells was evaluated using SAM2-1 and SAM2-2.

[0200] Example 2-3 First, a NiOx film was formed on the FTO layer of a commercially available glass / FTO substrate. The glass / FTO substrate was a substrate in which FTO constituting the first electrode layer was pre-laminated on a glass substrate. Next, a solution of a material for forming a hole transport layer dissolved in ethanol at a concentration of 1.0 mg / mL was spin-coated onto the NiOx layer. SAM2-1 obtained in Example 2-1 was used as the material for forming the hole transport layer. The coating film formed by spin-coating was dried at 100°C for 10 minutes to form a hole transport layer. A solution of 4-fluorophenylethylamine hydroiodide dissolved in DMF at a concentration of 80 mM was spin-coated onto the hole transport layer. The coating film formed by spin-coating was dried at 100°C for 5 minutes to form a passivation layer. A perovskite precursor solution, in which the perovskite precursor was dissolved at a concentration of 3.2 M in a mixed solvent of DMSO and DMF at a volume ratio of 1:4, was spin-coated onto the passivation layer. ２A mixture of FAI (metal halide) and MABr (halogenated organic compound) in a molar ratio of 1:0.83:0.17 was used. The coating film formed by spin coating was heated at 120°C for 30 minutes to form a photoelectric conversion layer. A solution of 1H,1H-undecafluorohexylamine hydroiodide dissolved in 2-propanol at a concentration of 0.25 mmol / L was spin coated onto the photoelectric conversion layer. The coating film formed by spin coating was dried at 100°C for 10 minutes to form a passivation layer. Further, fullerene was vapor-deposited to a thickness of 20 nm as an electron transport layer, followed by a 220 nm thick SnO ２ A thin film was formed by atomic deposition, and silver was then vapor-deposited to a thickness of 100 nm to form a second electrode layer on the passivation layer, thereby obtaining a perovskite solar cell.

[0201] Example 2-4 A perovskite solar cell was obtained in the same manner as in Example 2-3, except that SAM2-1 was changed to SAM2-2.

[0202] Comparative Example 2-1 A perovskite solar cell was obtained in the same manner as in Example 2-3, except that SAM2-1 was changed to SAM2-3 (N-(2-phosphonoethyl)-3,6-dimethoxycarbazole (MeO-2PACz)).

[0203] Comparative Example 2-2 A perovskite solar cell was obtained in the same manner as in Example 2-3, except that SAM2-1 was changed to N-(2-phosphonoethyl)-3,6-dimethylcarbazole (Me-2PACz).

[0204] Comparative Example 2-3 A perovskite solar cell was obtained in the same manner as in Example 2-3, except that SAM2-1 was changed to N-(2-phosphonoethyl)carbazole (2PACz).

[0205] The results of measuring the IV characteristics of the obtained perovskite solar cells of Examples 2-3 and 2-4, and Comparative Examples 2-1 to 2-3 are shown in Table 1 below.

[0206]

[0207] Table 2 shows that the perovskite solar cells of Examples 2-3 and 2-4, in which the hole transport layer contains one or more carbazole compounds selected from the carbazole compound (C1) and the carbazole compound (C2), have superior photoelectric conversion efficiency to the perovskite solar cells of Comparative Examples 2-1 to 2-3, in which the hole transport layer does not contain the carbazole compound (C1) or the carbazole compound (C2).

[0208] Example 3-1: Synthesis of SAM3-1 Tri-tert-butylphosphine (25 μL) was added to a mixture of diethyl (4-bromophenyl)phosphonate (0.520 g), 3,6-dimethylcarbazole (0.356 g), palladium acetate (0.0077 g), potassium carbonate (0.717 g), and 5 mL of xylene, which was being stirred under a nitrogen atmosphere at room temperature. The reaction mixture was then stirred at 120°C for 24 hours. The reaction mixture was then filtered through Celite. Volatiles were removed from the filtrate under reduced pressure. The crude product obtained as the residue was purified by silica gel column chromatography to obtain a white solid intermediate, [4-(3,6-dimethylcarbazol-9-yl)-phenyl]diethyl phosphate. １ H-NMR was as follows: １ H-NMR (400MHz, CDCl ３ ): δ = 8.02 (m, 2H), 7.89 (m, 2H), 7.69 (m, 2H), 7.36 (d, 2H), 7.21 (m, 2H), 4.21 (m, 4H), 2.53 (s, 6H), 1.40 (t, 6H)

[0209] Next, 0.361 g of the obtained intermediate was dissolved in 2 mL of 1,4-dioxane. 1 mL of trimethylsilyl bromide was added to the solution of the intermediate stirred at room temperature, and the mixture was stirred at room temperature for 24 hours. Then, the volatile matter was distilled off under reduced pressure. 1 mL of methanol and 1 mL of pure water were added to the obtained crude product, and the mixture was stirred at room temperature for 24 hours. Then, the precipitate was filtered and washed three times with 2 mL of pure water. The volatile matter was distilled off under vacuum at 65°C, yielding SAM3-1 as a white solid. １ H-NMR was as follows: １H-NMR (400MHz, DMSO-d ６ ): δ = 7.94 (m, 2H), 7.88 (m, 2H), 7.65 (dd, 2H), 7.30 (d, 2H), 7.19 (dd, 2H), 2.43 (s, 6H)

[0210] Example 3-2: Synthesis of SAM3-2 Tri-tert-butylphosphine (12 μL) was added to a mixture of diethyl (4-bromophenyl)phosphonate (0.500 g), carbazole (0.300 g), palladium acetate (0.0038 g), potassium carbonate (0.707 g), and 10 mL of xylene, which was being stirred under a nitrogen atmosphere at room temperature. The reaction mixture was then stirred at 120°C for 24 hours. The reaction mixture was then filtered through Celite. Volatiles were removed from the filtrate under reduced pressure. The crude product obtained as a residue was purified by silica gel column chromatography to obtain a white solid intermediate, [4-(carbazol-9-yl)-phenyl]diethyl phosphate. １ H-NMR was as follows: １ H-NMR (400MHz, CDCl ３ ): δ = 8.17 (m, 2H), 8.08 (m, 2H), 7.74 (m, 2H), 7.47 (d, 4H), 7.34 (td, 2H), 4.25 (m, 4H), 1.43 (t, 6H)

[0211] Next, 0.300 g of the obtained intermediate was dissolved in 3 mL of 1,4-dioxane. 1.1 mL of trimethylsilyl bromide was added to the solution of the intermediate stirred at room temperature, and the mixture was stirred at room temperature for 24 hours. Then, the volatile matter was distilled off under reduced pressure. 1 mL of methanol and 1 mL of pure water were added to the crude product obtained as the residue, and the mixture was stirred at room temperature for 24 hours. Then, the precipitate was filtered and washed three times with 2 mL of pure water. The volatile matter was distilled off under vacuum at 65°C, yielding SAM3-2 as a white solid. １ H-NMR was as follows: １ H-NMR (400MHz, DMSO-d ６ ): δ = 8.27 (d, 2H), 7.97 (m, 2H), 7.75 (dd, 2H), 7.46 (m, 4H), 7.32 (m, 2H)

[0212] Next, the performance of the cell was evaluated using SAM3-1.

[0213] Example 3-3 First, a NiOx film was formed on the FTO layer of a commercially available glass / FTO substrate. The glass / FTO substrate was a substrate in which FTO constituting the first electrode layer was pre-laminated on a glass substrate. Next, a solution of a material for forming a hole transport layer dissolved in ethanol at a concentration of 1.0 mg / mL was spin-coated onto the NiOx layer. SAM3-1 obtained in Example 3-1 was used as the material for forming the hole transport layer. The coating film formed by spin-coating was dried at 100°C for 10 minutes to form a hole transport layer. A solution of 4-fluorophenylethylamine hydroiodide dissolved in DMF at a concentration of 80 mM was spin-coated onto the hole transport layer. The coating film formed by spin-coating was dried at 100°C for 5 minutes to form a passivation layer. A perovskite precursor solution, in which the perovskite precursor was dissolved at a concentration of 3.2 M in a mixed solvent of DMSO and DMF at a volume ratio of 1:4, was spin-coated onto the passivation layer. ２ A mixture of (metal halide) and FAI and MABr (halogenated organic compound) in a molar ratio of 1:0.83:0.17 was used. The spin-coated coating film was heated at 120°C for 30 minutes to form a photoelectric conversion layer. A solution of 1H,1H-undecafluorohexylamine hydroiodide dissolved in 2-propanol at a concentration of 0.25 mmol / L was spin-coated onto the photoelectric conversion layer. The spin-coated coating film was dried at 100°C for 10 minutes to form a passivation layer. Further, fullerene was vapor-deposited to a thickness of 20 nm as an electron transport layer, followed by the formation of a 220 nm-thick SnO thin film as a buffer layer by atomic deposition. Silver was then vapor-deposited to a thickness of 100 nm, and a second electrode layer was laminated on the passivation layer to obtain a perovskite solar cell.

[0214] Comparative Example 3-1 A perovskite solar cell was obtained in the same manner as in Example 3-3, except that SAM3-1 was changed to SAM3-3 (N-(2-phosphonoethyl)-3,6-dimethylcarbazole (Me-2PACz)).

[0215] The results of measuring the IV characteristics of the obtained perovskite solar cells of Example 3-3 and Comparative Example 3-1 are shown in Table 1 below.

[0216]

[0217] Table 3 shows that the perovskite solar cell of Example 3-3, in which the hole transport layer contains the carbazole compound (C3) represented by the above formula (3-1), has a higher photoelectric conversion efficiency than the perovskite solar cell of Comparative Example 3-1, in which the hole transport layer does not contain the carbazole compound (C3) represented by the above formula (3-1).

[0218] Example 3-4 A perovskite solar cell was obtained in the same manner as in Example 3-3, except that SAM3-1 was changed to SAM3-2.

[0219] Comparative Example 3-2 A perovskite solar cell was obtained in the same manner as in Example 3-3, except that SAM-4 (N-(2-phosphonoethyl)carbazole (2PACz)) was used instead of SAM-1.

[0220] The results of measuring the IV characteristics of the obtained perovskite solar cells of Example 3-4 and Comparative Example 3-2 are shown in Table 2 below.

[0221]

[0222] Table 4 shows that the perovskite solar cell of Example 3-4, in which the hole transport layer contains the carbazole compound (C3) represented by the above-mentioned formula (3-1), has a higher photoelectric conversion efficiency than the perovskite solar cell of Comparative Example 3-2, in which the hole transport layer does not contain the carbazole compound (C3) represented by the above-mentioned formula (3-1).

[0223] Synthesis Example 4-1 Synthesis of Compound S4-1 (N-(2-aminoethyl)carbazole hydroiodide) Chloroethylamine hydrochloride (3.72 g) and tetrabutylammonium hydrogen sulfate (0.408 g) were added to a mixture of carbazole (5.01 g), sodium hydroxide (4.31 g), and acetonitrile (15 mL) that was stirred at room temperature under a nitrogen atmosphere. Next, the reaction solution was stirred at 90°C for 26 hours. After the reaction solution was cooled to room temperature, the solid was separated by filtration from the reaction solution. Volatiles were distilled off from the obtained filtrate under reduced pressure to obtain a residue. 5 mL of ethanol and 7 g of a 57% by mass aqueous solution of hydroiodic acid were added to the residue. The resulting mixture was stirred at room temperature for 24 hours. Thereafter, the volatiles were distilled off under reduced pressure to obtain a residue. 5 mL of ethanol was added to the residue, and the volatiles were distilled off under reduced pressure. This process was repeated five times to obtain Compound S4-1 as a white solid. The obtained compound S4-1 １ H-NMR was as follows: １ H-NMR (400MHz, DMSO-d ６ ): δ = 8.19 (d, 2H), 7.89 (br, 2, 3H), 7.66 (d, 2H), 7.50 (m, 2H), 7.25 (td, 2H), 4.61 (t, 2H), 3.26 (t, 2H)

[0224] Synthesis Example 4-2 Synthesis of Compound S4-2 (N-(2-acetylthioethyl)carbazole) Under a nitrogen atmosphere, a mixture of 2-bromoethylcarbazole (2.28 g), potassium thioacetate (1.14 g), sodium iodide (0.020 g), and dimethyl sulfoxide (8 mL) was stirred at room temperature for 7 days. 50 mL of pure water was added to the reaction mixture, and the reaction product was extracted five times with 20 mL of ethyl acetate. The organic phase was washed ten times with 10 mL of pure water and once with saturated brine, and dried over anhydrous magnesium sulfate. Volatiles were distilled off from the organic layer under reduced pressure to obtain the product. The obtained product was sufficiently pure spectroscopically. １ H-NMR was as follows: １ H-NMR (400MHz, CDCl ３ ): δ = 8.10 (dt, 2H), 7.51 (m, 4H), 7.25 (m, 2H), 4.46 (t, 2H), 3.26 (t, 2H), 2.40 (s, 3H)

[0225] Synthesis Example 4-3 Synthesis of Compound S4-3 (N-(2-mercaptoethyl)carbazole) Under a nitrogen atmosphere, 2-bromoethylcarbazole (3.09 g), sodium hydrosulfide (1.27 g), and sodium iodide (0.040 g) were added to 30 mL of tetrahydrofuran, and the reaction mixture was stirred at room temperature for 10 days. Thereafter, the solid was filtered off from the reaction mixture. From the obtained filtrate, the volatile matter was distilled off under reduced pressure to obtain a crude product as a residue. To the obtained crude product, 20 mL of ethanol was added. The ethanol solution was stirred for 10 minutes, and then the precipitate was filtered off. From the obtained filtrate, the volatile matter was distilled off under reduced pressure to obtain compound S4-3 as a pale yellow solid. １ H-NMR was as follows: １ H-NMR (400MHz, CDCl ３ ): δ = 8.31 (dt, 2H), 7.48 (m, 3H), 7.28 (m, 3H), 4.56 (t, 2H), 3.03 (t, 2H), 1.45 (t, 1H)

[0226] Synthesis Example 4-4 Compound S4-4 (bis[2-(carbazol-9-yl)ethyl]disulfide) Compound S4-2 (0.680 g), ethanol (8 mL), and 4 M aqueous sodium hydroxide solution (1.20 g) were mixed under a nitrogen atmosphere, and the reaction solution was stirred at room temperature for 6 days. Thereafter, the reaction solution was stirred overnight at 100° C. Next, the reaction solution was cooled to room temperature. 1 M hydrochloric acid was added to the reaction solution until the pH reached 1 to 2. The solid in the reaction solution was filtered, and the obtained solid was washed three times with pure water. Volatiles were distilled off from the washed solid under reduced pressure to obtain a crude product. Ethanol (1.5 mL) and 1 M hydrogen chloride (diethyl ether solution) (2 mL) were added to the obtained crude product (0.443 g), and the obtained mixture was stirred at room temperature for 13 days. Thereafter, the precipitate was filtered, and the obtained precipitate was washed with ethanol to obtain compound S4-4 as a white solid. １ H-NMR was as follows: １ H-NMR (400MHz, CDCl ３): δ = 8.11 (dd, 4H), 7.59-7.38 (m, 8H), 7.31-7.20 (m, 4H), 4.63 (t, 4H), 3.10 (t, 4H)

[0227] Example 4-1 First, a NiOx film was formed on the FTO layer of a commercially available glass / FTO substrate. The glass / FTO substrate was a substrate in which FTO, which constitutes the first electrode layer, had been pre-laminated on a glass substrate. Next, a solution of a material for forming a hole transport layer, dissolved in ethanol at a concentration of 1.0 mg / mL, was spin-coated onto the NiOx layer. 2PACz, MeO-2PACz, and N-(2-acetylthioethyl)carbazole (compound S4-2) were used as materials for forming the hole transport layer. The amounts of 2PACz and MeO-2PACz used were equimolar. The mass ratio of compound S4-2 to the total mass of 2PACz, MeO-2PACz, and compound S-2 was 20% by mass. In other words, a material for forming a hole transport layer containing 20% ​​by mass of compound S4-2 was used. The coating film formed by spin coating was dried at 100°C for 10 minutes to form a hole transport layer. A solution in which 4-fluorophenylethylamine hydroiodide was dissolved in DMF at a concentration of 80 mM was spin coated onto the hole transport layer. The coating film formed by spin coating was dried at 100°C for 5 minutes to form a passivation layer. A perovskite precursor solution in which the perovskite precursor was dissolved at a concentration of 3.2 M in a mixed solvent of DMSO and DMF at a volume ratio of 1:4 was spin coated onto the passivation layer. PbI was used as the perovskite precursor. ２A mixture of (metal halide) and FAI and MABr (halogenated organic compound) in a molar ratio of 1:0.83:0.17 was used. The spin-coated coating film was heated at 120°C for 30 minutes to form a photoelectric conversion layer. A solution of 1H,1H-undecafluorohexylamine hydroiodide dissolved in 2-propanol at a concentration of 0.25 mmol / L was spin-coated onto the photoelectric conversion layer. The spin-coated coating film was dried at 100°C for 10 minutes to form a passivation layer. Further, fullerene was vapor-deposited to a thickness of 20 nm as an electron transport layer, followed by the formation of a 220 nm-thick SnO thin film as a buffer layer by atomic deposition. Silver was then vapor-deposited to a thickness of 100 nm, and a second electrode layer was laminated on the passivation layer to obtain a perovskite solar cell.

[0228] Example 4-2 2PACz, MeO-2PACz, and N-(2-mercaptoethyl)carbazole (compound S4-3) were used as materials for forming a hole transport layer. The amounts of 2PACz and MeO-2PACz used were equimolar. The mass ratio of compound S4-3 to the total mass of 2PACz, MeO-2PACz, and compound S4-3 was 5 mass%. In other words, a material for forming a hole transport layer containing 5 mass% of compound S4-3 was used. A perovskite solar cell was obtained in the same manner as in Example 4-1, except for the above conditions.

[0229] Example 4-3 2PACz, MeO-2PACz, and N-(2-aminoethyl)carbazole hydroiodide (compound S-1) were used as materials for forming a hole transport layer. The amounts of 2PACz and MeO-2PACz used were equimolar. The mass ratio of compound S4-1 to the total mass of 2PACz, MeO-2PACz, and compound S4-1 was 5 mass%. In other words, a material for forming a hole transport layer containing 5 mass% of compound S4-1 was used. A perovskite solar cell was obtained in the same manner as in Example 4-1, except for the above conditions.

[0230] Example 4-4 A perovskite solar cell was obtained in the same manner as in Example 4-3, except that the ratio of the mass of compound S4-1 to the total mass of 2PACz, MeO-2PACz, and compound S4-1 was 10 mass %.

[0231] Comparative Example 4-1 A perovskite solar cell was obtained in the same manner as in Example 4-1, except that the material for forming the hole transport layer was changed to an equimolar mixture of 2PACz and MeO-2PACz.

[0232] The results of measuring the IV characteristics of the obtained perovskite solar cells of Examples 4-1 to 4-4 and Comparative Example 4-1 are shown in Table 5 below.

[0233]

[0234] Table 5 shows that the perovskite solar cells of the examples, in which the hole transport layer contains a combination of the phosphono group-containing carbazole compound represented by the formula (4-1) and the heteroatom-containing carbazole compound represented by the formula (4-2), have superior photoelectric conversion efficiency to the perovskite solar cells of the comparative examples, in which the hole transport layer contains only the phosphono group-containing carbazole compound represented by the formula (4-1).

[0235] REFERENCE SIGNS LIST 1 Perovskite solar cell 10 Substrate 20 First electrode layer 30 Hole transport layer 40 Photoelectric conversion layer 50 Passivation layer 60 Electron transport layer 70 Second electrode layer

Claims

1. A device comprising a first electrode layer, a hole transport layer, a photoelectric conversion layer, an electron transport layer, and a second electrode layer in this order, wherein the hole transport layer is represented by the following formula (1-1): (HO) ２ P(=O)-(CH ２ ) ｎ１ -X １ -Ph １ -CH ２ CH ２ -NH ２ (1-1) (In formula (1-1), n1 is an integer of 0 to 10, and X １ is a single bond, an oxygen atom, -NR-, or a sulfur atom, and Ph １ is a phenylene group which may have a substituent, and R is a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. ２ P(=O)-(Ph ２ ) ｎ２ -Cbz １ (2-1) (In formula (2-1), Ph ２ represents a phenylene group which may be substituted with an alkyl group having from 1 to 6 carbon atoms and / or an alkoxy group having from 1 to 6 carbon atoms, and Cbz １ is a 9H-carbazole-9-yl group optionally substituted with one or more substituents selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom, and n2 is an integer of from 2 to 10. ２ P(=O)-Ph ２ -Cbz ２ (2-2) (In formula (2-2), Ph ２ represents a phenylene group which may be substituted with an alkyl group having from 1 to 6 carbon atoms and / or an alkoxy group having from 1 to 6 carbon atoms, and Cbz ２ is a 9H-carbazol-9-yl group substituted with one or more substituents selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom; and Cbz ２ The number of substituents of the 9H-carbazol-9-yl group as the group is one.) A self-assembled monolayer II containing one or more carbazole compounds (C2) selected from carbazole compounds (C2-2) represented by the following formula (3-1): (HO) ２ P(=O)-(Ph ３ ) ｎ３ -Cbz ３ (3-1) (In formula (3-1), Ph ３ represents a phenylene group which may be substituted with an alkyl group having from 1 to 6 carbon atoms and / or an alkoxy group having from 1 to 6 carbon atoms, and Cbz ３ is a 9H-carbazole-9-yl group optionally substituted with one or more groups selected from the group consisting of alkyl groups having from 1 to 6 carbon atoms and halogen atoms, and n3 is an integer of from 1 to 10; or a self-assembled monolayer III containing a carbazole compound (C3) represented by the following formula (4-1): (HO) ２ P(=O)-R １ -Cbz ４ (4-1) (In formula (4-1), R １ is a divalent organic group, and Cbz ４ is a 9H-carbazol-9-yl group which may be substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom. ２ -R ２ -Cbz ４ (4-2) Cbz ４ -R ２ - (S) ｎ４ -R ２ -Cbz ４ (4-3) (In formula (4-2), X ２ is a heteroatom or a heteroatom-containing group, and R ２ is a divalent hydrocarbon group, and X ２ is a heteroatom-containing group, R ２ The divalent hydrocarbon group represented by Cbz is bonded to a heteroatom in the heteroatom-containing group. ４ is Cbz in formula (4-1). ４ In formula (4-3), Cbz ４ is Cbz in formula (4-1). ４ is the same as R ２ is R in formula (4-2). ２ and n4 represents an integer of 2 to 8. A perovskite solar cell comprising a heteroatom-containing carbazole compound represented by the following formula (1):

2. The perovskite solar cell according to claim 1, wherein the hole transport is a self-assembled monolayer I, and the hole transport layer comprises a carbazole compound (C0).

3. The carbazole compound (C0) is N-(2-phosphonoethyl)carbazole, N-(2-phosphonoethyl)-3,6-dimethoxycarbazole, N-(2-phosphonoethyl)-3,6-dimethylcarbazole, N-(2-phosphonoethyl)-2,7-dimethoxycarbazole, N-(2-phosphonoethyl)-2,7-dimethylcarbazole, N-(3-phosphonopropyl)carbazole, N-(3-phosphonopropyl)-3,6-dimethoxycarbazole, N-(3-phosphonopropyl)-3,6-dimethylcarbazole, N-(3-phosphonopropyl)-2,7-dimethoxycarbazole, N-(3-phosphonopropyl)-2,7-dimethylcarbazole, N-(4-phosphonobutyl)carbazole, N-(4-phosphonobutyl)carbazole, N-(4-phosphonobutyl)carbazole, N-(4-phosphonobutyl)carbazole, N-(4-phosphonopropyl)-3,6-dimethoxycarbazole, N-(4-phosphonopropyl)-3,6-dimethyl ...

3. The perovskite solar cell according to claim 2, comprising one or more members selected from the group consisting of N-(4-phosphonobutyl)-3,6-dimethoxycarbazole, N-(4-phosphonobutyl)-3,6-dimethylcarbazole, N-(4-phosphonobutyl)-2,7-dimethoxycarbazole, N-(4-phosphonobutyl)-2,7-dimethylcarbazole, N-(4-phosphonophenyl)carbazole, N-(4-phosphonophenyl)-3,6-dimethoxycarbazole, N-(4-phosphonophenyl)-3,6-dimethylcarbazole, N-(4-phosphonophenyl)-2,7-dimethoxycarbazole, and N-(4-phosphonophenyl)-2,7-dimethylcarbazole.

4. The perovskite solar cell according to any one of claims 1 to 3, wherein the hole transport is self-assembled monolayer I, and the ratio of the number of moles of the phenethylamine compound to the total number of moles of compounds constituting the self-assembled monolayer I is 0.1 mol % or more and 10 mol % or less.

5. The perovskite solar cell according to claim 1, wherein the hole transport is a self-assembled monolayer II, and in the carbazole compound (C2-1) and the carbazole compound (C2-2), the substituent on the 9H-carbazol-9-yl group is an alkoxy group having from 1 to 6 carbon atoms.

6. The perovskite solar cell according to claim 1, wherein the hole transport is a self-assembled monolayer II, and the self-assembled monolayer II comprises the carbazole compound (C2-1) in which n2 is 2.

7. - (Ph ２ ) ｎ２ The perovskite solar cell according to claim 6, wherein the group represented by - is a biphenyl-4,4'-diyl group.

8. The perovskite solar cell according to claim 1, wherein the hole transport is a self-assembled monolayer II, and the self-assembled monolayer II comprises the carbazole compound (C2-2) in which the substituent is bonded to the 3-position of the 9H-carbazol-9-yl group.

9. The perovskite solar cell according to claim 1, wherein the hole transport is a self-assembled monolayer III, and n3 is 1.

10. The hole transport is a self-assembled monolayer III, and the Ph ３ The perovskite solar cell according to claim 1, wherein is a p-phenylene group.

11. The hole transport is a self-assembled monolayer VI, and the phosphono group-containing carbazole compound is N-(2-phosphonoethyl)carbazole, N-(2-phosphonoethyl)-3,6-dimethoxycarbazole, N-(2-phosphonoethyl)-3,6-dimethylcarbazole, N-(2-phosphonoethyl)-2,7-dimethoxycarbazole, N-(2-phosphonoethyl)-2,7-dimethylcarbazole, N-(3-phosphonopropyl)carbazole, N-(3-phosphonopropyl)-3,6-dimethoxycarbazole, N-(3-phosphonopropyl)-3,6-dimethylcarbazole, N-(3-phosphonopropyl)-2,7-dimethoxycarbazole, N-(3-phosphonopropyl)-2,7-dimethylcarbazole, N-(4-phosphonopropyl)-2,7-dimethylcarbazole, or N-(4-phosphonopropyl)-2,7-dimethylcarbazole.

2. The perovskite solar cell according to claim 1, comprising at least one selected from the group consisting of N-(4-phosphonobutyl)carbazole, N-(4-phosphonobutyl)-3,6-dimethoxycarbazole, N-(4-phosphonobutyl)-3,6-dimethylcarbazole, N-(4-phosphonobutyl)-2,7-dimethoxycarbazole, N-(4-phosphonobutyl)-2,7-dimethylcarbazole, N-(4-phosphonophenyl)carbazole, N-(4-phosphonophenyl)-3,6-dimethoxycarbazole, N-(4-phosphonophenyl)-3,6-dimethylcarbazole, N-(4-phosphonophenyl)-2,7-dimethoxycarbazole, and N-(4-phosphonophenyl)-2,7-dimethylcarbazole.

12. The perovskite solar cell according to claim 1 or 11, wherein the hole transport is a self-assembled monolayer VI, and the ratio of the number of moles of the heteroatom-containing carbazole compound to the total number of moles of compounds constituting the self-assembled monolayer is 0.1 mol % or more and 10 mol % or less.

13. The perovskite solar cell according to claim 1 or 11, wherein the hole transport is a self-assembled monolayer VI, the heteroatom-containing carbazole compound is a compound represented by formula (4-2), the heteroatom is a halogen atom, and the heteroatom-containing group is a group containing one or more heteroatoms selected from the group consisting of oxygen atoms, sulfur atoms, nitrogen atoms, phosphorus atoms, and silicon atoms.

14. The perovskite solar cell according to claim 1 or 11, wherein the hole transport is a self-assembled monolayer VI, and the ratio of the mass of the heteroatom-containing carbazole compound to the total mass of the phosphono group-containing carbazole compound and the heteroatom-containing carbazole compound is 1 mass% or more and 30 mass% or less.

15. A liquid composition for forming a hole transport layer in a perovskite solar cell, comprising: a compound represented by the following formula (1-1): (HO) ２ P(=O)-(CH ２ ) ｎ１ -X １ -Ph １ -CH ２ CH ２ -NH ２ (1-1) (In formula (1-1), n1 is an integer of 0 to 10, and X １ is a single bond, an oxygen atom, -NR-, or a sulfur atom, and Ph １ is a phenylene group which may have a substituent, and R is a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, or ２ P(=O)-(Ph ２ ) ｎ２ -Cbz １ (2-1) (In formula (2-1), Ph ２ represents a phenylene group which may be substituted with an alkyl group having from 1 to 6 carbon atoms and / or an alkoxy group having from 1 to 6 carbon atoms, and Cbz １ is a 9H-carbazole-9-yl group optionally substituted with one or more substituents selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom, and n2 is an integer of from 2 to 10. ２ P(=O)-Ph ２ -Cbz ２ (2-2) (In formula (2-2), Ph ２ represents a phenylene group which may be substituted with an alkyl group having from 1 to 6 carbon atoms and / or an alkoxy group having from 1 to 6 carbon atoms, and Cbz ２ is a 9H-carbazol-9-yl group substituted with one or more substituents selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom; and Cbz ２ The number of substituents on the 9H-carbazol-9-yl group as the carbazole compound (C2) is one. ２ P(=O)-(Ph ３ ) ｎ３ -Cbz ３ (3-1) (In formula (3-1), Ph ３ represents a phenylene group which may be substituted with an alkyl group having from 1 to 6 carbon atoms and / or an alkoxy group having from 1 to 6 carbon atoms, and Cbz ３ is a 9H-carbazole-9-yl group optionally substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms and a halogen atom, and n3 is an integer of from 1 to 10), or ２ P(=O)-R １ -Cbz ４ (4-1) (In formula (4-1), R １ is a divalent organic group, and Cbz ４ is a 9H-carbazol-9-yl group which may be substituted with one or more groups selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom. ２ -R ２ -Cbz ４ (4-2) Cbz ４ -R ２ - (S) ｎ４ -R ２ -Cbz ４ (4-3) (In formula (4-2), X ２ is a heteroatom or a heteroatom-containing group, and R ２ is a divalent hydrocarbon group, and X ２ is a heteroatom-containing group, R ２ The divalent hydrocarbon group represented by Cbz is bonded to a heteroatom in the heteroatom-containing group. ４ is Cbz in formula (4-1). ４ In formula (4-3), Cbz ４ is Cbz in formula (4-1). ４ is the same as R ２ is R in formula (4-2). ２ and n4 represents an integer of 2 to 8.

16. The following formula (1-1): (HO) ２ P(=O)-(CH ２ ) ｎ１ -X １ -Ph １ -CH ２ CH ２ -NH ２ (1-1) (In formula (1-1), n1 is an integer of 0 to 10, and X １ is a single bond, an oxygen atom, -NR-, or a sulfur atom, and Ph １ is a phenylene group which may have a substituent, and R is a hydrogen atom or a hydrocarbon group having from 1 to 6 carbon atoms.

17. The following formula (2-1): (HO) ２ P(=O)-(Ph ２ ) ｎ２ -Cbz １ (2-1) (In formula (2-1), Ph represents a phenylene group which may be substituted with an alkyl group having 1 to 6 carbon atoms and / or an alkoxy group having 1 to 6 carbon atoms; Cbz represents a phenylene group which may be substituted with an alkyl group having 1 to 6 carbon atoms; １ is a 9H-carbazole-9-yl group optionally substituted with one or more substituents selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom, and n2 is an integer of from 2 to 10. ２ P(=O)-Ph ２ -Cbz ２ (2-2) (In formula (2-2), Ph ２ represents a phenylene group which may be substituted with an alkyl group having from 1 to 6 carbon atoms and / or an alkoxy group having from 1 to 6 carbon atoms, and Cbz ２ is a 9H-carbazol-9-yl group substituted with one or more substituents selected from the group consisting of an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, and a halogen atom; and Cbz ２ and the number of substituents on the 9H-carbazole-9-yl group as the carbazole compound (C2-2) is one.

18. The following formula (3-1): (HO) ２ P(=O)-(Ph ３ ) ｎ３ -Cbz ３ (3-1) (In formula (3-1), Ph ３ represents a phenylene group which may be substituted with an alkyl group having from 1 to 6 carbon atoms and / or an alkoxy group having from 1 to 6 carbon atoms, and Cbz ３ is a 9H-carbazol-9-yl group which may be substituted with one or more groups selected from the group consisting of alkyl groups having from 1 to 6 carbon atoms and halogen atoms, and n ３ is an integer of 1 or more and 10 or less.

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