Photoelectric conversion element and solar cell module

Abstract

The purpose of the present invention is to provide a photoelectric conversion element that shows excellent photoelectric conversion characteristics and has low variation.　A photoelectric conversion element 10 according to one mode of the present invention has a structure in which a first electrode 12, a hole transport layer 13, a photoelectric conversion layer 14, an electron transport layer 15, and a second electrode 16 are layered in that order. The photoelectric conversion layer 14 includes a perovskite compound. The hole transport layer 13 includes an insulating compound and a monomolecular hole transport material. The hole transport material includes a compound represented by the chemical formula (I). (I): Ar1–(L1–X1)n. In the chemical formula (I), Ar 1 is a structure that includes an aromatic ring, atoms that constitute the aromatic ring may include heteroatoms, and Ar1 may have a substituent other than –L1–X1. n is an integer 1 or greater, and if n is 2 or greater, the structures represented by –L1–X1 may be mutually identical or different. L1 is a divalent linking group linking Ar1 and X1 or is a single bond. X1 is a group capable of chemical bonding or hydrogen bonding with a p-type metallic oxide semiconductor.

Description

Photoelectric conversion element and solar cell module

[0001] The present invention relates to a photoelectric conversion element and a solar cell module.

[0002] In recent years, solar power generation has attracted attention as a clean energy source, and the development of solar cells has progressed. As one of these next-generation solar cells that can be manufactured at low cost, solar cells that use perovskite materials in the light absorption layer have rapidly attracted attention. For example, Non-Patent Document 1 reports a solution-type solar cell that uses a perovskite material in the light absorption layer. Furthermore, Non-Patent Document 2 reports that solid-state perovskite solar cells exhibit high efficiency.

[0003] Known basic structures of perovskite solar cells include a forward structure in which an electron transport layer, a light absorption layer (perovskite layer), a hole transport layer (also called a hole transport layer), and a back electrode are stacked in this order on an electrode, and an inverted structure in which a hole transport layer, a light absorption layer, an electron transport layer, and a back electrode are stacked in this order on an electrode. A porous electron transport layer may also be provided between the electron transport layer and the perovskite layer. Of these, an organic semiconductor hole transport material is generally used for the hole transport layer (e.g., Non-Patent Documents 3 to 10).

[0004] Journal of the American Chemical Society, 2009, 131, 6050-6051.Science, 2012, 388, 643-647.ACS Appl. Mater. Interfaces, 2017, 9, 24778-24787.Energy Environ. Sci., 2014, 7, 1454-1460.J. Mater. Chem. A, 2014, 2, 6305-6309.J. Mater. Chem. A, 2015, 3, 12139-12144.J. Mater. Chem. A, 2018, 6, 7950-7958.ACS Appl. Mater. Interfaces, 2015, 7, 11107-11116.Energy & Environmental Science 2014, 7, 2963-2967.Adv. Energy Mater., 2018, 8, 1801892.

[0005] However, conventional perovskite solar cells have insufficient photoelectric conversion efficiency. To improve the photoelectric conversion efficiency of solar cells, it is particularly important to improve the properties of the hole transport layer. Examples of hole transport materials used in the hole transport layer include traxene compounds (Non-Patent Document 3), diketopyrrolopyrrole compounds (Non-Patent Document 4), thiophene compounds (Non-Patent Documents 5 and 6), and dithienopyrroles (Non-Patent Document 7). However, few compounds have been reported that can exhibit photoelectric conversion efficiencies sufficient for use in perovskite solar cells. Therefore, Spiro-OMeTAD ([2,2',7,7'-tetrakis(N,N-di-p-methoxyphenylamino)-9,9'-spirobifluorene]) has been proposed as a hole transport material for dye-sensitized solar cells, but it is known to have poor heat resistance (Non-Patent Document 8). In addition, polymer materials with a triphenylamine skeleton, such as PTAA (poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]), are also known to have poor light resistance. Furthermore, when these materials are used as hole transport materials for the p-buffer layer, the addition of LiTFSI salt (lithium bis(trifluoromethanesulfonyl)imide) as an additive is required to improve conductivity, which is thought to be one of the causes of device degradation (Non-Patent Document 9). Recently, a carbazole-type hole transport material containing phosphonic acid has been reported (Non-Patent Document 10). This compound reacts with indium tin compounds (ITO) used as transparent electrodes to form a monolayer on the transparent electrode. This monolayer-forming hole transport compound is an excellent compound, with reported photoelectric conversion efficiencies exceeding 20%. However, if the hole transport layer does not sufficiently cover the electrode, the electrode and photoelectric conversion layer may come into contact, resulting in reduced photoelectric conversion characteristics and insufficient durability.

[0006] Therefore, an object of the present invention is to provide a photoelectric conversion element and a solar cell module that exhibit excellent photoelectric conversion characteristics and have little variation in characteristics.

[0007] One aspect of the present invention is a photoelectric conversion element, which includes a first electrode, a hole transport layer, a photoelectric conversion layer, an electron transport layer, and a second electrode stacked directly or indirectly in this order, the photoelectric conversion layer containing a perovskite compound, and the hole transport layer containing an insulating compound and a compound represented by the following chemical formula (I) in contact with the main surface of the first electrode on the photoelectric conversion layer side: Ar １ - (L １ -X １ ) n... (I) In the above chemical formula (I), Ar １ is a structure containing an aromatic ring, and the atoms constituting the aromatic ring may contain a heteroatom, and Ar １ Is, -L １ -X １ n is an integer of 1 or more, and when n is 2 or more, -L １ -X １ The structures represented by the formula (I) may be the same or different from each other. １ is Ar １ and X １ and X is a divalent linking group or a single bond. １ is a group capable of forming a chemical bond or a hydrogen bond with the first electrode. In the photoelectric conversion element of the above aspect, the hole transport layer may contain a compound represented by the following chemical formula (II): 1 -L ２ -X ２ (II) A 1 is an atomic group containing one or more substituents or structures selected from the group consisting of an alkoxy group, a hydroxy group, a carboxy group, a dihydroxyphosphoryl group, a dialkylphosphoryl group, a hydroxysulfonyl group, an amino group, a monoalkylamino group, a dialkylamino group, a monoarylamino group, a diarylamino group, a monoalkylaminocarbonyl group, a dialkylaminocarbonyl group, an alkylcarbonyloxy group, an alkoxycarbonyl group, an aminocarbonyl group, an aminocarbonylamino group, an alkylcarbonylamino group, an alkylsulfonylamino group, an aminosulfonyl group, and a nitrogen-containing heterocyclic group. ２ is A 1 and X ２X is a divalent linking group or a single bond. ２ is a group capable of forming a chemical bond or a hydrogen bond with the first electrode. The compound represented by the chemical formula (I) may form a monolayer. The insulating compound may be at least one selected from metal oxides, metal nitrides, insulating organic compounds, and organic-inorganic hybrid compounds. The insulating compound may be in a particulate form. In this case, the average particle size of the insulating compound may be in the range of 1 nm to 200 nm. X in the chemical formula (I) １ are dihydroxyphosphoryl groups (-P=O(OH) ２ ), carboxy group (-COOH), sulfo group (-SO ３ H), boronic acid group (-B(OH) ２ ), trihalogenated silyl group (—SiX ３ , where X is a halo group), trialkoxysilyl group (—Si(OR) ３ wherein R is an alkyl group), a trihydroxysilyl group, and a dialkylphosphoryl group. ２ each independently represents a dihydroxyphosphoryl group (-P=O(OH) ２ ), carboxy group (-COOH), sulfo group (-SO ３ H), boronic acid group (-B(OH) ２ ), trihalogenated silyl group (—SiX ３ , where X is a halo group), trialkoxysilyl group (—Si(OR) ３ , where R is an alkyl group), a trihydroxysilyl group, and a dialkylphosphoryl group. The perovskite compound may be an organic-inorganic perovskite compound. The mass ratio of the mass (m1) of the compound represented by chemical formula (I) to the mass (m2) of the insulating compound may satisfy the relationship of the following formula (A): m1 / m2=1 / 10 to 1 / 20000 (A). An intermediate layer containing nickel oxide may be formed between the first electrode and the hole transport layer. Another aspect of the present invention is a solar cell module. The solar cell module includes the photoelectric conversion element of any of the above-mentioned aspects.

[0008] According to the present invention, it is possible to provide a photoelectric conversion element that exhibits excellent photoelectric conversion characteristics and suppresses variations in characteristics.

[0009] Fig. 1 is a cross-sectional view showing an example of the configuration of a photoelectric conversion element according to an embodiment. Fig. 2 is a plan view showing a manufacturing process of a solar cell module according to an example. Fig. 3 is a plan view showing a manufacturing process of a solar cell module according to an example. Fig. 4 is a plan view showing a manufacturing process of a solar cell module according to an example. Fig. 5 is a cross-sectional view taken along line AA' in Fig. 4.

[0010] The present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following description. Note that the following description will be given assuming that the photoelectric conversion element according to the embodiment is a solar cell.

[0011] [Photoelectric Conversion Element] FIG. 1 is a cross-sectional view showing an example of the configuration of a photoelectric conversion element 10 according to an embodiment. For ease of explanation, FIG. 1 is drawn schematically with appropriate omissions and exaggerations. As shown in FIG. 1, the photoelectric conversion element 10 has a laminated structure in which a first electrode 12, a hole transport layer 13, a photoelectric conversion layer 14, an electron transport layer 15, and a second electrode 16 are laminated in this order on a support (also referred to as a substrate, base material, etc.). In this embodiment, the electron transport layer 15 is present as shown in FIG. 1, but the electron transport layer 15 is an optional layer. The photoelectric conversion layer 14 and the second electrode 16 may be in contact with each other as long as the desired photoelectric conversion characteristics are obtained. In other words, the first electrode 12, the hole transport layer 13, the photoelectric conversion layer 14, and the second electrode 16 may be laminated directly or indirectly in this order. 1 , for example, an interface layer may be provided between the photoelectric conversion layer 14 and the electron transport layer 15, and an electron injection layer may be provided between the electron transport layer 15 and the second electrode 16. Each component of the photoelectric conversion element 10 will be described in detail below.

[0012] [Support] The support 11 is not particularly limited, and may be, for example, a substrate that can be used for a photoelectric conversion element such as a general solar cell. Examples of the substrate include glass, a plastic plate, a plastic film, and an inorganic crystal. In addition, a substrate having at least one film selected from a metal film, a semiconductor film, a conductive film, and an insulating film formed on a part or all of the surface of the substrate can also be suitably used as the support 11. The size, thickness, etc. of the support 11 are also not particularly limited, and may be the same as or equivalent to that of a photoelectric conversion element such as a general solar cell.

[0013] [First Electrode] The first electrode 12 is, for example, a layer that supports the hole transport layer 13 and has a function of extracting holes from the photoelectric conversion layer 14. The first electrode 12 is also, for example, a layer that functions as a cathode (positive electrode).

[0014] The first electrode 12 may be formed directly on the support 11, for example. The first electrode 12 may be a transparent electrode made of a conductor, for example. The transparent electrode is not particularly limited, and may be made of a metal oxide, a metal nanowire such as silver, a conductive polymer such as polyethylenedioxythiophene, or a carbon material such as a carbon nanotube or graphene. For example, a tin-doped indium oxide (ITO) film, an impurity-doped indium oxide (In ２ O ３Examples of suitable materials include a ZnO film, an impurity-doped zinc oxide (ZnO) film, a fluorine-doped tin dioxide (FTO) film, a laminate film formed by laminating two or more of these, and gold, silver, copper, aluminum, tungsten, titanium, chromium, nickel, and cobalt. These may be used alone or in combination, and may be in the form of a single layer or a laminate. These films may also function as a diffusion barrier layer, for example. The thickness of the first electrode 12 is not particularly limited, but it is preferable to adjust it so that the sheet resistance is 5 to 15 Ω / □ (per unit area). The method for forming the first electrode 12 is not particularly limited, but it can be obtained by, for example, a known film formation method depending on the material to be formed. The shape of the first electrode 12 is also not particularly limited, but it may be formed in a film shape or a lattice shape such as a mesh. The method for forming the first electrode 12 on the support 11 is not particularly limited, but it may be a known method, for example, vacuum film formation such as vacuum deposition or sputtering is preferred. The first electrode 12 may be patterned. The patterning method is not particularly limited, but includes, for example, a method of immersing in a laser or etching solution, and a method of patterning using a mask during vacuum film formation. Any of these methods may be used in this embodiment. The first electrode 12 may also be used in combination with metal wiring or the like to reduce electrical resistance. The material of the metal wiring (metal lead wire) is not particularly limited, but includes, for example, aluminum, copper, silver, gold, platinum, and nickel. The metal lead wire can be formed on the first substrate by, for example, vapor deposition, sputtering, or pressure bonding, and then a layer of ITO or FTO is provided thereon, or the metal lead wire can be provided on ITO or FTO for combined use.

[0015] [Hole Transport Layer] As shown in Figure 1, the hole transport layer 13 contains an insulating compound and a hole transport material. At least a portion of the insulating compound and at least a portion of the hole transport material are in contact with the main surface of the first electrode 12 on the photoelectric conversion layer 14 side. In addition, in the hole transport layer 13, the hole transport material functions as a hole transporter. By including an insulating compound in addition to the hole transport material as the material for the hole transport layer 13, the degree of scattering of light incident on the hole transport layer 13 increases. As a result, it is presumed that the amount of light captured by the photoelectric conversion layer 14 increases, and thus the photoelectric conversion efficiency increases.

[0016] Insulating compounds are compounds that do not easily conduct electricity, and are generally ８ ~10 １８ The resistivity is expressed in Ω cm. The insulating compound may be at least one selected from metal oxides, metal nitrides, insulating organic compounds, and organic-inorganic hybrid compounds. Examples of the metal oxide include silica (SiO ２ , refractive index 1.48, volume resistivity 1×10 １６ Ω cm), alumina (Al ２ O ３ , refractive index 1.64, volume resistivity 1×10 １４ Ω cm), zirconia (ZrO ２ ), ceria (CeO ２ , refractive index 2.13, volume resistivity 1×10 １０ Ω cm), magnesia (MgO), yttria (Y ２ O ３ , refractive index 1.18, volume resistivity 1×10 １３ Ω cm), tantalum pentoxide (Ta ２ O ５ ), hafnia (HfO ２ ), strontium oxide, lanthanum oxide, barium titanate (BaTiO ３ , refractive index 2.43 to 2.49, volume resistivity 1×10 １２ Ω cm), strontium titanate (SrTiO ３) and the like. Examples of metal nitrides include aluminum nitride (AlN), silicon nitride (SiN), aluminum gallium nitride (AlGaN), boron nitride (BN), and the like. Examples of insulating organic compounds include acrylic resin, epoxy resin, polystyrene, and the like. Organic-inorganic hybrid compounds are compounds having both carbon atoms and silicon atoms, and compounds having both a siloxane bond and a partial structure having a carbon atom (such as a hydrocarbon group) are preferred, and specific examples include silsesquioxane. Among these, it is particularly preferred to use metal oxides as insulating compounds. The volume resistivity of the insulating compound is 1×10 ８ Ω cm or more is preferable, and 1×10 ９ More preferably, Ω cm or more, and 1×10 １０ The volume resistivity of the insulating compound is more preferably 1×10 １８ Ω cm or less is preferable, and 1×10 １７ Ω cm or less is more preferable, and 1×10 １６ The refractive index of the insulating compound is preferably 1.20 or more, more preferably 1.40 or more. The refractive index of the insulating compound is, for example, 2.50 or less. The refractive index of the insulating compound can be measured by the critical angle method.

[0017] The method for forming the hole transport layer 13 containing an insulating compound is not limited and can be selected appropriately depending on the purpose, but a wet film-forming method is preferred. A preferred wet film-forming method is a method in which a dispersion liquid in which a powder or sol of the insulating compound is dispersed is prepared and applied. The wet film-forming method is not particularly limited and can be selected appropriately depending on the purpose, and examples include dipping, spraying, wire bar coating, spin coating, roller coating, blade coating, and gravure coating. Various wet printing methods can be used, such as relief printing, offset printing, gravure printing, intaglio printing, rubber printing, and screen printing.

[0018] Methods for producing insulating compound particles are not particularly limited. For example, in the case of metal oxides, examples include solid-phase reactions using known raw materials such as oxides or carbonates, coprecipitation, hydrothermal synthesis, and sol-gel methods. The shape of the particles is also not particularly limited, and examples include spherical, irregular, rod-shaped, and anisotropic plate-like shapes. Furthermore, the insulating compound in this embodiment is preferably in a particulate form. When the insulating compound is in a particulate form, the average particle size of the particles is preferably 1 to 200 nm, more preferably 1 to 100 nm, and even more preferably 1.5 to 50 nm. The average particle size of the insulating compound is the average value calculated by measuring the diameters (or major axes if the particles are not perfectly round) of 100 particles of the insulating compound using a SEM. Note that, after the hole transport layer 13 has been formed, the average particle size can be measured by photographing a cross section of the hole transport layer 13 using a SEM and measuring the diameters (or major axes if the particles are not perfectly round) of 100 particles of the insulating compound. Before forming the hole transport layer 13, the average particle size of the particulate insulating compound used to form the hole transport layer 13 may be measured.

[0019] The method for preparing the insulating compound dispersion is not particularly limited and can be appropriately selected depending on the purpose. For example, a method of mechanically pulverizing using a known milling device can be used. This preparation method can produce an insulating compound dispersion by dispersing a particulate insulating compound alone or a mixture of an insulating compound and a resin in water or a solvent. Examples of resins used in the dispersion include polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, acrylic acid esters, and methacrylic acid esters, silicone resins, phenoxy resins, polysulfone resins, polyvinyl butyral resins, polyvinyl formal resins, polyester resins, cellulose ester resins, cellulose ether resins, urethane resins, phenolic resins, epoxy resins, polycarbonate resins, polyarylate resins, polyamide resins, and polyimide resins. These may be used alone or in combination of two or more.

[0020] Examples of solvents include water, alcohol solvents, ketone solvents, ester solvents, ether solvents, amide solvents, halogenated hydrocarbon solvents, and hydrocarbon solvents. Examples of alcohol solvents include methanol, ethanol, isopropyl alcohol, and α-terpineol. Examples of ketone solvents include acetone, methyl ethyl ketone, and methyl isobutyl ketone. Examples of ester solvents include ethyl formate, ethyl acetate, and n-butyl acetate. Examples of ether solvents include diethyl ether, dimethoxyethane, tetrahydrofuran, dioxolane, and dioxane. Examples of amide solvents include N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone. Examples of halogenated hydrocarbon solvents include dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene, bromobenzene, iodobenzene, and 1-chloronaphthalene. Examples of hydrocarbon solvents include n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, cumene, etc. These may be used alone or in combination of two or more.

[0021] To prevent particle re-aggregation, an acid, a surfactant, a chelating agent, or the like may be added to a dispersion containing an insulating compound or a paste containing an insulating compound obtained by a sol-gel method or the like. Examples of acids include hydrochloric acid, nitric acid, and acetic acid. Examples of surfactants include polyoxyethylene octylphenyl ether. Examples of chelating agents include acetylacetone, 2-aminoethanol, and ethylenediamine. Adding a thickener to improve film formability is also an effective method. Examples of thickeners include polyethylene glycol, polyvinyl alcohol, and ethyl cellulose.

[0022] The hole transport layer 13 contains a compound represented by the following chemical formula (I) in addition to the insulating compound described above: Ar １ - (L １ -X １ ) n... (I) In the above chemical formula (I), Ar １ is a structure containing an aromatic ring, and the atoms constituting the aromatic ring may contain a heteroatom, and Ar １ Is, -L １ -X １ n is an integer of 1 or more, and when n is 2 or more, -L １ -X １ The structures represented by the formula (I) may be the same or different from each other. The upper limit of n is preferably 3 or 4. １ is Ar １ and X １ and X is a divalent linking group or a single bond. １ is a group capable of forming a chemical bond or a hydrogen bond with the first electrode 12 .

[0023] (Compound represented by chemical formula (I)) In chemical formula (I), X １ are each independently a dihydroxyphosphoryl group (-P=O(OH) ２ ), carboxy group (-COOH), sulfo group (-SO ３ H), boronic acid group (-B(OH) ２ ), trihalogenated silyl group (—SiX ３ , where X is a halo group), trialkoxysilyl group (—Si(OR) ３ where R is an alkyl group), a trihydroxysilyl group, and a dialkylphosphoryl group.

[0024] In formula (I), Ar １ Specifically, for example, an aromatic ring group, a group in which a plurality of aromatic ring groups are bonded by single bonds, and a group in which one or more aromatic ring groups are condensed with a ring that does not have aromaticity are preferred.

[0025] The aromatic ring group may be monocyclic or polycyclic (for example, 2 to 14 rings) and may have one or more (for example, 1 to 10) heteroatoms (such as nitrogen atoms, sulfur atoms, and / or oxygen atoms). The number of ring atoms in the aromatic ring group is preferably 5 to 40. Examples of the aromatic ring group include a benzene ring group, a pyrrole ring group, a furan ring group, a thiophene ring group, and a group formed by condensing two or more (for example, 2 to 14) rings selected from these.

[0026] Examples of the aromatic ring group constituting the group formed by a plurality of aromatic ring groups bonded together by single bonds include the aromatic ring groups described above. The number of aromatic ring groups bonded together by single bonds is preferably 2 to 6. Specific examples of the group formed by a plurality of aromatic ring groups bonded together by single bonds include a biphenyl ring group and a bithiophene ring group.

[0027] Examples of aromatic ring groups constituting the group in which one or more aromatic ring groups are fused to a ring that does not have aromaticity include the aromatic ring groups described above. Among the groups in which one or more aromatic ring groups are fused to a ring that does not have aromaticity, the number of aromatic ring groups fused to the ring that does not have aromaticity is preferably 2 to 6, for example. Among the groups in which one or more aromatic ring groups are fused to a ring that does not have aromaticity, there may be only one or more rings that do not have aromaticity. Among the groups in which one or more aromatic ring groups are fused to a ring that does not have aromaticity, the rings that do not have aromaticity may each independently be monocyclic or polycyclic (e.g., 2 to 14 rings) and may have one or more (e.g., 1 to 10) heteroatoms (such as nitrogen atoms, sulfur atoms, and / or oxygen atoms). Specific examples of the group in which one or more aromatic ring groups are fused to a ring having no aromaticity include a phenothiazine ring group and a 1,2:3,4:5,6:7,8-tetrakis[imino(1,2-phenylene)]cyclooctatetraene ring group.

[0028] In the chemical formula (I), the divalent linking group L １ For example, *1-alkylene group-*2 and *1-alkylene group-aromatic ring group-*2 are exemplified. １ *2 indicates the bonding position on the X １The alkylene group may be linear or branched, and preferably has 1 to 6 carbon atoms. The aromatic ring group is, for example, Ar １ Examples of the aromatic ring group that may be the alkylene group include the same aromatic ring groups as those mentioned above. The alkylene group and the aromatic ring group may further have a substituent.

[0029] Specific examples of the compound represented by chemical formula (I) include compounds (A-01) to (A-21) having the following structures.

[0030] The compound represented by chemical formula (I) may be formed, for example, as a monolayer on the first electrode 12. The compound represented by chemical formula (1) may be formed in a dispersed form, in other words, in a form in which gaps exist, on the main surface of the first electrode 12. The insulating compound described above may be formed in a form that fills these gaps.

[0031] (Compound Represented by Chemical Formula (II)) The hole transport layer 13 may contain a compound represented by the following chemical formula (II) in addition to the insulating compound and the compound represented by chemical formula (I). In other words, a compound represented by the following chemical formula (II) may be used in combination as a co-adsorbent. In a preferred embodiment of the hole transport layer 13, the compound represented by chemical formula (II) is chemically bonded or hydrogen-bonded to the first electrode 12. １ -L ２ -X ２ (II) A 1is an organic amino group such as a monoalkylamino group, a dialkylamino group, a monoarylamino group, a diarylamino group, an aminocarbonylamino group, an alkylcarbonylamino group, or an alkylsulfonylamino group, an alkoxy group, a hydroxy group, a carboxy group, a dihydroxyphosphoryl group, a dialkylphosphoryl group, a hydroxysulfonyl group, an amino group, a monoalkylaminocarbonyl group, a dialkylaminocarbonyl group, an alkylcarbonyloxy group, an alkoxycarbonyl group, an aminocarbonyl group, an aminosulfonyl group, a nitrogen-containing heterocyclic group (which may or may not have aromaticity, may be monocyclic or polycyclic, and preferably has 5 to 15 ring atoms, and preferably has 1 to 5 nitrogen atoms in the ring atoms). Preferably, it may have a heteroatom (preferably 1 to 3) other than a nitrogen atom. For example, it is an atomic group containing one or more substituents or structures selected from the group consisting of a pyridine ring group, a quinoline ring group, an aziridine ring group, an azetidine ring group, a pyrrolidine ring group, an imidazolidine ring group, an imidazolidin-2-one ring group, a 2,3-dihydro-1H-pyrrole ring group, a pyrrole ring group, a pyrazole ring group, an imidazole ring group, a 1H-1,2,3-triazole ring group, a 2H-1,2,3-triazole ring group, a thiazole ring group, a morpholine ring group, a piperidine ring group, a piperazine ring group, a pyrazine ring group, a hexamethyleneimine ring group, a 1H-azepine ring group, an indole ring group, a 2,3-trimethyleneindoline ring group, and a quinoxaline ring group. 1 may be the substituents or structures listed above. When the substituents or structures listed above have an alkyl group portion (including the alkyl group portion of an alkoxy group), the alkyl groups may each independently be linear or branched, and preferably have 1 to 8 carbon atoms. ２ is A 1 and X ２ X is a divalent linking group or a single bond. ２ is a group capable of forming a chemical bond or a hydrogen bond with the first electrode.

[0032] In the compound represented by chemical formula (II), A 1However, the hydrophilic property improves the wettability of the perovskite solution that is applied to the hole transport layer 13. Improved wettability to the perovskite solution allows the perovskite layer to be applied with a uniform thickness, which is thought to have the effect of reducing variations in thickness, particularly when applying to a large area.

[0033] In the chemical formula (II), A 1 When the atomic group represented by the formula (I) contains a monoarylamino group or a diarylamino group, the aryl group portion in these groups may be, for example, Ar １ Examples of the aromatic ring group that can be A include the same groups as those mentioned above. 1 is an organic amino group such as a monoalkylamino group, a dialkylamino group, a monoarylamino group, a diarylamino group, an aminocarbonylamino group, an alkylcarbonylamino group, or an alkylsulfonylamino group, an alkoxy group, a dialkylphosphoryl group, an amino group, a monoalkylaminocarbonyl group, a dialkylaminocarbonyl group, an alkylcarbonyloxy group, an alkoxycarbonyl group, an aminocarbonyl group, an aminosulfonyl group, or a nitrogen-containing heterocyclic group, and may further have one or more (preferably 1 to 6) substituents. The substituents that these groups may further have are the X in chemical formula (II) ２ or -L ２ -X ２ In the compound represented by chemical formula (II), as a whole, -L in chemical formula (II) may be the same group as the group that can be formed by ２ -X ２ It is also preferred that there are two or more (for example, 2 to 6) groups that can form

[0034] In the chemical formula (II), X ２ are each independently a dihydroxyphosphoryl group (-P=O(OH) ２ ), carboxy group (-COOH), sulfo group (-SO ３ H), boronic acid group (-B(OH) ２ ), trihalogenated silyl group (—SiX ３ , where X is a halo group), or a trialkoxysilyl group (—Si(OR)３ where R is an alkyl group), a trihydroxysilyl group, and a dialkylphosphoryl group.

[0035] In the chemical formula (II), the divalent linking group L ２ is, for example, an alkylene group (which may be linear or branched, and preferably has 1 to 8 carbon atoms), a vinylene group, a vinylidene group, an acetylene group, an aromatic ring group (for example, Ar １ a non-aromatic ring group (which may be monocyclic or polycyclic and may have a heteroatom, for example, a piperazine ring group); —O—, —S—, —NR Ｎ - (R Ｎ is a hydrogen atom or an alkyl group. The alkyl group may be linear or branched, and preferably has 1 to 8 carbon atoms), and divalent linking groups formed by combining two or more of these (for example, 2 to 6). The divalent linking groups formed by combining two or more of these may be combinations of groups of the same type (however, this does not include combinations in which alkylene groups are bonded consecutively). These divalent linking groups may further have one or more (for example, 1 to 6) substituents, if possible, and for example, one or more (for example, 1 to 6) A as a substituent. １ or X ２ may have the same groups as those explained above.

[0036] Specific examples of the compound represented by chemical formula (II) include 3-methoxypropionic acid, 3-hydroxypropionic acid, 2-hydroxypropionic acid, malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, phthalic acid, terephthalic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid, methylenesuccinic acid, allylmalonic acid, isopropylidenesuccinic acid, acetylenedicarboxylic acid, dimethyl terephthalate, diethyl terephthalate, 4,4'-biphenyldicarboxylic acid ... Diethylphenyldicarboxylate, 4-methoxybenzoic acid, 3,4-dimethoxybenzoic acid, 4-(methylamino)benzoic acid, 4-(methylamino)benzenesulfonic acid, 4-(methylamino)butanoic acid, 3-(carboxymethylamino)propionic acid, 6-acetoxy-2-naphthoic acid, acetylsalicylic acid, 4-(methoxycarbonyl)cyclohexanecarboxylic acid, 4-(methoxycarbonyl)phenylboronic acid, 4-(N,N-diethylaminocarbonyl)phenylboronic acid, 3-( (methylaminocarbonyl)acrylic acid, N-(aminocarbonyl)aspartic acid, 4-acetylaminobenzoic acid, 2-(acetylamino)acrylic acid, gallic acid, 4-pyridinecarboxylic acid, 6-quinolinecarboxylic acid, aspartic acid, 2,2-diethoxyethylphosphonic acid, methylenediphosphonic acid, 1,2-ethylenediphosphonic acid, tetraethyl 1,2-ethylenediphosphonate, 1,3-propylenediphosphonic acid, 3,4-dimethoxyphenylphosphonic acid, (4-hydroxybenzoyl) [3-(3-carboxypiperazin-1-yl)propyl]phosphonic acid, (pyridin-4-ylmethyl)phosphonic acid, (pyridin-3-ylmethyl)phosphonic acid, 4-phosphonobenzoic acid, 3-phosphonopropionic acid, 4-phosphonobutyric acid, diethyl(4-methoxybenzyl)phosphonate, p-carboxybenzenesulfonylamide, 2-(dimethylamino)ethanesulfonic acid, 1,2-ethanesulfonic acid, and the like.

[0037] L ２Specific examples include alkylenes such as 1,1-ethylene, 1,2-ethylene, 1,3-propylene, and 2-ethyl-1,6-hexylene, and the alkylene may be partly an alkenylene having a carbon-carbon double bond or an alkynylene having a triple bond. Specific examples also include arylenes such as 1,2-phenylene, 1,4-phenylene, 1,5-naphthylene, and 4,4'-biphenylene, and divalent heterocycles such as 2,5-thienylene, 5,5'-bithienylene, 2,5-thieno[3,2-b]thienylene, and 2,6-pyridylene.

[0038] In the compound represented by the above chemical formula (II), examples of salts formed from a nitrogen atom and an anion include ammonium salts, aziridinium salts, azirinium salts, azetidinium salts, pyrrolidinium salts, pyrrolinium salts, pyrazolinium salts, pyrrolinium salts, pyrazolinium salts, imidazolinium salts, triazolinium salts, tetrazolinium salts, piperidinium salts, piperazinium salts, pyridinium salts, pyrazinium salts, morpholinium salts, thiazolinium salts, azepanium salts, azepinium salts, indolinium salts, indolinium salts, quinolinium salts, isoquinolinium salts, quinoxalinium salts, phenanthrolinium salts, phenazinium salts, etc. The acid that reacts with the compound represented by the above chemical formula (II) to form a salt may be any of organic acids, inorganic acids, or a mixture thereof, which will be described later as acids that form acid addition salts.

[0039] Specific examples of the compound represented by chemical formula (II) include compounds (B-01) to (B-52) having the following structures.

[0040] The compound represented by chemical formula (II) may be formed, for example, as a monolayer on the first electrode 12 .

[0041] In the hole transport layer 13, the total content of the compound represented by chemical formula (I) (including the above-mentioned salt form) and the compound represented by chemical formula (II) (including the above-mentioned salt form) is preferably 70 to 100 mass %, more preferably 90 to 100 mass %, and even more preferably 99 to 100 mass %, relative to the mass of the hole transport layer 13.

[0042] The molar ratio of the compound represented by chemical formula (I) (including the above-mentioned salt forms) to the compound represented by chemical formula (II) (including the above-mentioned salt forms) is preferably 1:100 to 1:1, more preferably 1:80 to 1:2, and even more preferably 1:50 to 1:5.

[0043] In the hole transport layer 13, the ratio of [mass of the compound represented by chemical formula (I)] to [mass of the insulating compound] is preferably 1 / 10 to 1 / 20,000, and more preferably 1 / 50 to 1 / 10,000. The mass of the compound represented by chemical formula (I) can be calculated, for example, from the amount of adsorption measured by cyclic voltammetry. The mass of the insulating compound was measured by spin-coating a solution in which the insulating compound was dispersed on a surface such as glass, and observing the cross-section of the resulting film with an electron microscope. The measured film thickness was assumed to be densely packed with nanoparticles, and the weight was calculated from the value obtained by multiplying the film thickness by 0.74.

[0044] The thickness of the hole transport layer 13 is preferably 10 to 300 nm, more preferably 20 to 150 nm, and even more preferably 30 to 100 nm.

[0045] (Method of Forming Hole Transport Layer) The method of forming the hole transport layer 13 is not particularly limited, and examples thereof include a method of adsorbing a compound represented by chemical formula (I) or a compound represented by chemical formulas (I) and (II) onto the first electrode 12 and then applying a dispersion of an insulating compound, a method of applying a dispersion of an insulating compound onto the first electrode 12 and then adsorbing a compound represented by chemical formula (I) or a compound represented by chemical formulas (I) and (II), and a method of including a compound represented by chemical formula (I) or a compound represented by chemical formulas (I) and (II) in a dispersion of an insulating compound and applying the solution onto the first electrode 12. Among these, the most preferred method is a method of adsorbing a compound represented by chemical formula (I) or a compound represented by chemical formulas (I) and (II) onto the first electrode 12 and then applying a dispersion of an insulating compound.

[0046] The method for adsorbing the compound represented by chemical formula (I) or the compounds represented by chemical formulas (I) and (II) onto the first electrode 12 is not particularly limited. For example, the compound represented by chemical formula (I) or the compounds represented by chemical formulas (I) and (II) may be dissolved in a solvent and brought into contact with the first electrode 12 to bond. The bond between the compound represented by chemical formula (I) and the first electrode 12 and the bond between the compound represented by chemical formula (II) and the first electrode 12 are not particularly limited and may be a physical bond or a chemical bond. The type of bond is also not particularly limited and may be, for example, a hydrogen bond, an ester bond, a chelate bond, or the like. The solvent for dissolving the compound represented by chemical formula (I) and the compound represented by chemical formula (II) is also not particularly limited. For example, it may be either water or an organic solvent, or both. More specifically, examples of the solvent include water, alcohols such as methanol, ethanol, and 2-propanol, ethers such as diethyl ether and diisopropyl ether, ketones such as acetone and methyl isobutyl ketone, esters such as ethyl acetate, isobutyl acetate, and γ-butyrolactone, heterocycles such as tetrahydrofuran and thiophene, amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone, sulfoxides such as dimethyl sulfoxide, sulfones such as diethyl sulfone and sulfolane, nitriles such as acetonitrile and 3-methoxypropionitrile, aromatic compounds such as benzene, toluene, and chlorobenzene, halogen-based solvents such as dichloromethane and chloroform, and fluorine-based solvents such as chlorofluorocarbons, hydrochlorofluorocarbons, and hydrofluorocarbons. These may be used alone or in combination of two or more.

[0047] The specific method for adsorbing the compound represented by chemical formula (I) or the compounds represented by chemical formula (I) and chemical formula (II) onto the first electrode 12 to form a monolayer is not particularly limited, and examples thereof include known methods such as dipping, spraying, spin coating, and bar coating. The temperature during adsorption is not particularly limited, but is preferably −20° C. to 100° C., and more preferably 0° C. to 50° C. The adsorption time is also not particularly limited, but is preferably 1 second to 48 hours, and more preferably 10 seconds to 1 hour.

[0048] After the adsorption treatment, for example, washing may or may not be performed. The washing method is not particularly limited, and for example, a known method may be used appropriately.

[0049] After the adsorption treatment or the washing, a heat treatment may or may not be performed. The temperature of the heat treatment is preferably 50°C to 150°C, more preferably 70°C to 120°C. The heat treatment time is preferably 1 second to 48 hours, more preferably 10 seconds to 1 hour. The heat treatment may be performed, for example, in the atmosphere or in a vacuum.

[0050] In the present embodiment, the "substituent" is not particularly limited, and examples thereof include an alkyl group, an alkenyl group, an alkynyl group, an unsaturated aliphatic hydrocarbon group, an alkoxy group, an aralkyl group, an aryl group, an arylalkenyl group, a heteroaryl group, a halogen atom (a fluorine atom, a chlorine atom, and / or a bromine atom), a hydroxy group (-OH), a mercapto group (-SH), an alkylthio group (-SR, where R is an alkyl group), an amino group, a sulfo group, a nitro group, a diazo group, a cyano group, a nitrile group, and a trifluoromethyl group.

[0051] In addition, in this embodiment, when a compound has isomers such as tautomers or stereoisomers (e.g., geometric isomers, conformational isomers, and optical isomers), any of these isomers can be used in this embodiment unless otherwise specified. In addition, in this embodiment, when a compound represented by chemical formula (I) or chemical formula (II) can form a salt, the salt can also be used in this embodiment unless otherwise specified. The salt may be an acid addition salt or a base addition salt. Furthermore, the acid that forms the acid addition salt may be an inorganic acid or an organic acid, and the base that forms the base addition salt may be an inorganic base or an organic base. Examples of the inorganic acid include, but are not limited to, sulfuric acid, phosphoric acid, hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, hypofluorite acid, hypochlorous acid, hypobromous acid, hypoiodite acid, fluorite acid, chlorous acid, bromous acid, iodite acid, fluoric acid, chloric acid, bromic acid, iodic acid, perfluoric acid, perchloric acid, perbromic acid, and periodic acid. Examples of the organic acid include, but are not limited to, p-toluenesulfonic acid, methanesulfonic acid, oxalic acid, p-bromobenzenesulfonic acid, carbonic acid, succinic acid, citric acid, benzoic acid, and acetic acid. Examples of the inorganic base include, but are not limited to, ammonium hydroxide, alkali metal hydroxides, alkaline earth metal hydroxides, carbonates, and bicarbonates. More specifically, examples include sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate, sodium bicarbonate, potassium bicarbonate, calcium hydroxide, and calcium carbonate. The organic base is not particularly limited, and examples thereof include ethanolamine, triethylamine, tris(hydroxymethyl)aminomethane, etc. The method for producing these salts is also not particularly limited, and they can be produced, for example, by a method in which the above-mentioned acid or base is appropriately added to the above-mentioned compound by a known method.

[0052] The mass ratio between the mass (m1) of the compound represented by chemical formula (I) and the mass (m2) of the insulating compound preferably satisfies the relationship of the following formula (A): m1 / m2=1 / 10 to 1 / 20000 (A)

[0053] [Photoelectric Conversion Layer] The photoelectric conversion layer 14 is not particularly limited and may be the same as a photoelectric conversion layer used in a photoelectric conversion element such as a general solar cell. The photoelectric conversion layer 14 contains, for example, a perovskite compound. The perovskite compound may be, for example, an organic-inorganic perovskite compound represented by the following chemical formula (III): XαYβZγ... (III)

[0054] In the chemical formula (III), the ratio of α:β:γ is 3:1:1, and β and γ represent integers greater than 1. X represents a halogen ion, Y represents an organic compound having an amino group, and Z represents a metal ion. The photoelectric conversion layer 14 containing the perovskite compound is preferably disposed adjacent to the electron transport layer 15 described below. Note that the ratio of α:β:γ does not necessarily have to be 3:1:1, and may be, for example, 3:1.05:0.95.

[0055] X in the chemical formula (III) is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include halogen ions such as chlorine, bromine, and iodine ions. These may be used alone or in combination of two or more.

[0056] Examples of Y in the chemical formula (III) include alkylamine compound ions (organic compounds having an amino group) such as methylamine, ethylamine, n-butylamine, and formamidine, and alkali metal ions such as cesium, potassium, and rubidium, which are not limited to organic ions. The alkylamine compound ions and alkali metal ions may be used alone or in combination of two or more. Furthermore, organic (alkylamine compound ions) and inorganic (alkali metal ions) may be used in combination; for example, cesium ions and formamidine may be used in combination.

[0057] Z in the chemical formula (III) is not particularly limited and can be appropriately selected depending on the purpose. Examples include metals such as lead, indium, antimony, tin, copper, and bismuth. These may be used alone or in combination of two or more. Lead is particularly preferred, and a combination of lead and tin is particularly preferred. The perovskite layer preferably exhibits a layered perovskite structure in which layers of metal halide and layers of aligned organic cation molecules are alternately stacked. The perovskite layer may contain an alkali metal. When the perovskite layer contains at least an alkali metal, it is advantageous in terms of increasing output. Examples of alkali metals include cesium, rubidium, and potassium. Among these, cesium is preferred.

[0058] As described above, the photoelectric conversion layer 14 may be a perovskite layer formed from a perovskite compound. The method for forming such a perovskite layer is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a method in which a solution in which a metal halide and an alkylamine halide are dissolved or dispersed is applied and then dried.

[0059] In addition, examples of methods for forming a perovskite layer include a two-stage precipitation method in which a solution in which a metal halide is dissolved or dispersed is applied and dried, and then the substrate is immersed in a solution in which a halogenated alkylamine is dissolved, thereby forming a perovskite compound.

[0060] Another method for forming a perovskite layer is to apply a solution in which a metal halide and an alkylamine halide are dissolved or dispersed, while adding a poor solvent (a solvent with low solubility) for the perovskite compound to precipitate crystals.

[0061] Another method for forming a perovskite layer is to deposit a metal halide in a gas filled with methylamine or the like.

[0062] A particularly preferred method for forming a perovskite layer is to apply a solution in which a metal halide and a halogenated alkylamine are dissolved or dispersed, while adding a poor solvent for the perovskite compound to precipitate crystals. The method for applying these solutions is not particularly limited and can be appropriately selected depending on the purpose, and examples include immersion, spin coating, spraying, dipping, roller coating, and air knife coating. Another method for applying the solution may be, for example, a method in which precipitation occurs in a supercritical fluid using carbon dioxide or the like. Examples of the poor solvent to be used in the method of precipitating crystals by adding a poor solvent include hydrocarbons such as n-hexane and n-octane; alcohols such as methanol, ethanol, and 2-propanol; ethers such as diethyl ether and diisopropyl ether; ketones such as acetone and methyl isobutyl ketone; esters such as ethyl acetate, isobutyl acetate, and γ-butyrolactone; nitriles such as acetonitrile and 3-methoxypropionitrile; aromatic hydrocarbon compounds such as benzene, toluene, and chlorobenzene; halogenated solvents such as dichloromethane and chloroform; and fluorinated solvents such as chlorofluorocarbons, hydrochlorofluorocarbons, and hydrofluorocarbons.

[0063] The thickness of the photoelectric conversion layer 14 (for example, a light absorption layer, such as a perovskite layer) is not particularly limited, but from the viewpoint of further suppressing performance degradation due to defects and peeling, it is preferably 50 to 1200 nm, and more preferably 200 to 1000 nm.

[0064] An interface layer may be formed between the photoelectric conversion layer 14 and the electron transport layer 15. Because various crystal defects exist on the surface and crystal grain boundaries of the photoelectric conversion layer 14, it is effective to provide a compound made of an organic salt between the photoelectric conversion layer 14 and the electron transport layer 15 in order to passivate these defects. Specific examples of this organic salt include salts obtained from monovalent or divalent cations formed by reaction of protons with amino compounds such as methylamine, n-butylamine, t-butylamine, n-hexyl-dimethylamine, pyridine, aniline, 2-phenylethylamine, 5-aminovaleric acid, ethylenediamine, morpholine, piperidine, and piperazine as cations, and anions formed from halogens such as fluorine, chlorine, bromine, and iodine, carboxylic acids, sulfuric acid, nitric acid, phosphoric acid, oxalic acid, phthalic acid, succinic acid, thiocyanic acid, and isocyanic acid.

[0065] If this interface layer is formed too thick, it may become a resistance component, so it is preferable to form it thin. There are no particular limitations on the formation method, and examples include forming it using a solution in which the above-mentioned salt is dissolved, by spin coating, ink jetting, casting, spray coating, etc.

[0066] [Electron Transport Layer] The material used for the electron transport layer 15 is not particularly limited and can be appropriately selected depending on the purpose, but is preferably a semiconductor material. The semiconductor material is not particularly limited and known materials can be used, such as elemental semiconductors, compound semiconductors, and organic n-type semiconductors.

[0067] The elemental semiconductor is not particularly limited, but examples thereof include silicon and germanium.

[0068] The compound semiconductor is not particularly limited, but examples thereof include metal chalcogenides, specifically oxides of titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, tantalum, etc.; sulfides of cadmium, zinc, lead, silver, antimony, bismuth, etc.; selenides of cadmium, lead, etc.; tellurides of cadmium, etc. Other compound semiconductors include phosphides of zinc, gallium, indium, cadmium, etc., gallium arsenide, copper-indium-selenide, copper-indium-sulfide, etc.

[0069] The organic n-type semiconductor is not particularly limited, but examples thereof include perylene tetracarboxylic anhydride, perylene tetracarboxylic diimide compound, naphthalene diimide-bithiophene copolymer, benzobisimidazobenzophenanthroline polymer, C ６０ , C ７０ , PCBM ([6,6]-phenyl-C ６１ -butyric acid methyl ester), fullerane compounds such as carbonyl-bridged bithiazole compounds, ALq ３ (tris(8-quinolinolato)aluminum), triphenylene bipyridyl compounds, silole compounds, oxadiazole compounds, and the like.

[0070] Among the above-mentioned materials used for the electron transport layer 15, organic n-type semiconductors are particularly preferred.

[0071] The material used to form the electron transport layer 15 may be one type alone or two or more types in combination. The crystal type of the semiconductor material is not particularly limited and may be appropriately selected depending on the purpose, and may be single crystal, polycrystalline, or amorphous.

[0072] The thickness of the electron transport layer 15 is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 5 nm to 1000 nm, more preferably 10 nm to 700 nm.

[0073] The method for forming the electron transport layer 15 is not particularly limited and can be appropriately selected depending on the purpose. Examples of the method include a method for forming a thin film in a vacuum (vacuum film-forming method) and a wet film-forming method. Examples of vacuum film-forming methods include sputtering, pulsed laser deposition (PLD), ion beam sputtering, ion-assisted deposition, ion plating, vacuum evaporation, atomic layer deposition (ALD), and chemical vapor deposition (CVD). Examples of wet film-forming methods include a method for forming a film by applying a solvent in which an electron transport material is dissolved, and in the case of an oxide semiconductor, a sol-gel method. The sol-gel method is a method in which a gel is produced from a solution through chemical reactions such as hydrolysis, polymerization, and condensation, and then densification is promoted by heat treatment. When the sol-gel method is used, the method for applying the sol solution is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include dipping, spraying, wire bar coating, spin coating, roller coating, blade coating, and gravure coating, and wet printing methods such as relief printing, offset printing, gravure printing, intaglio printing, rubber printing, and screen printing. The temperature during the heat treatment after application of the sol solution is preferably 80° C. or higher, and more preferably 100° C. or higher.

[0074] After forming the electron transport layer 15, an electron injection layer (hole blocking layer) may be formed between the electron transport layer 15 and the second electrode 16. Examples of materials used for the electron injection layer include BCP (bathocuproine), which may be doped with cesium. The electron injection layer preferably has a thickness of 1 to 100 nm, more preferably 3 to 20 nm.

[0075] [Second Electrode] The second electrode 16 (which may be, for example, a back electrode) is, for example, a layer having a function of extracting electrons from the photoelectric conversion layer 14 via the electron transport layer. The second electrode 16 is, for example, a layer that functions as an anode (negative electrode).

[0076] The second electrode 16 may be formed directly on the electron transport layer (also referred to as the electron injection layer) 15. The material of the second electrode 16 is not particularly limited, and for example, the same material as that of the first electrode 12 can be used. The shape, structure, and size of the second electrode 16 are not particularly limited, and can be appropriately selected depending on the purpose. Examples of materials for the second electrode 16 include metals, carbon compounds, conductive metal oxides, and conductive polymers.

[0077] Examples of the metal include platinum, gold, silver, copper, and aluminum.

[0078] Examples of the carbon compounds include graphite, fullerene, carbon nanotubes, and graphene.

[0079] Examples of the conductive metal oxide include ITO, FTO, and ATO.

[0080] Examples of the conductive polymer include polythiophene and polyaniline.

[0081] The material used to form the second electrode 16 may be one type alone or two or more types in combination.

[0082] The second electrode 16 can be formed on the electron transport layer 15 by coating, laminating, vacuum deposition, CVD, bonding, or other methods depending on the type of material used and the type of hole transport layer 13 .

[0083] Furthermore, in the photoelectric conversion element 10 of this embodiment, it is preferable that at least one of the first electrode 12 and the second electrode 16 is substantially transparent. When using the photoelectric conversion element 10 of this embodiment, it is preferable that the electrodes are transparent and that incident light is incident from the electrode side. In this case, it is preferable to use a light-reflecting material for the back electrode (the electrode opposite the transparent electrode, for example, the second electrode 16), and metal, glass on which a conductive oxide is vapor-deposited, plastic, metal thin film, etc. are preferably used. It is also effective to provide an anti-reflection layer on the electrode on the incident light side.

[0084] The configuration of the photoelectric conversion element 10 is not limited to the configuration shown in FIG. 1 . For example, the support 11 may be disposed on the opposite side to that shown in FIG. 1 (above the second electrode 16 in FIG. 1 ), and the second electrode 16, electron transport layer 15, photoelectric conversion layer 14, hole transport layer 13, and first electrode 12 may be stacked on the support 11 in the aforementioned order. Furthermore, as described above, other components may or may not be present between the support 11, first electrode 12, hole transport layer 13, photoelectric conversion layer 14, electron transport layer 15, and second electrode 16. Although the example in which the first electrode 12 is a transparent electrode and the second electrode 16 is a back electrode has been described, the photoelectric conversion element 10 is not limited thereto. For example, in the photoelectric conversion element 10, the first electrode 12 may be a back electrode and the second electrode 16 may be a transparent electrode.

[0085] [Sealing] The photoelectric conversion element 10 (e.g., a solar cell) of this embodiment is preferably sealed to protect the device (the photoelectric conversion element 10 of this embodiment) from water and oxygen. The sealing structure is not particularly limited, and may be the same as that of a general photoelectric conversion element (e.g., a solar cell). Specifically, for example, a sealing material may be applied only to the outer periphery of the photoelectric conversion element 10 of this embodiment and then covered with glass or a film, a sealing material may be applied to the entire surface of the photoelectric conversion element 10 of this embodiment and then covered with glass or a film, or a sealing material may simply be applied to the entire surface of the photoelectric conversion element 10 of this embodiment.

[0086] The material of the sealing member is not particularly limited and can be selected appropriately depending on the purpose. For example, it is preferable to use an epoxy resin or an acrylic resin and harden it, but it may be unhardened or only partially hardened.

[0087] The epoxy resin is not particularly limited, but examples thereof include water-dispersed, solvent-free, solid, heat-curable, curing agent-mixed, and UV-curable resins. Of these, heat-curable and UV-curable resins are preferred, with UV-curable resins being more preferred. Even UV-curable resins can be heated, and it is preferable to heat them even after UV curing. Specific examples of epoxy resins include bisphenol A, bisphenol F, novolac, cyclic aliphatic, long-chain aliphatic, glycidyl amine, glycidyl ether, and glycidyl ester resins. These may be used alone or in combination of two or more. It is also preferable to mix a curing agent or various additives with the epoxy resin as needed. Commercially available epoxy resin compositions can be used in this embodiment. Among these, there are epoxy resin compositions developed and commercially available for use in solar cells and organic EL devices, which can be particularly effectively used in this embodiment. Examples of commercially available epoxy resin compositions include TB3118, TB3114, TB3124, and TB3125F (manufactured by ThreeBond Co., Ltd.), WorldRock 5910, WorldRock 5920, and WorldRock 8723 (manufactured by Kyoritsu Chemical Industries Co., Ltd.), and WB90US(P) and WB90US-HV (manufactured by Moresco).

[0088] The acrylic resin is not particularly limited, but commercially available acrylic resins developed for solar cells and organic EL devices can be effectively used. Examples of commercially available acrylic resin compositions include TB3035B and TB3035C (manufactured by ThreeBond Co., Ltd.).

[0089] The curing agent is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include amine-based, acid anhydride-based, polyamide-based, and other curing agents. Examples of amine-based curing agents include aliphatic polyamines such as diethylenetriamine and triethylenetetramine, and aromatic polyamines such as metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone. Examples of acid anhydride-based curing agents include phthalic anhydride, tetrahydrophthalic anhydride and hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, pyromellitic anhydride, HET anhydride, and dodecenyl succinic anhydride. Examples of other curing agents include imidazoles and polymercaptan. These may be used alone or in combination of two or more.

[0090] The additives are not particularly limited and can be appropriately selected depending on the purpose. Examples include fillers, gap agents, polymerization initiators, desiccants (moisture absorbers), curing accelerators, coupling agents, flexibilizers, colorants, flame retardant aids, antioxidants, and organic solvents. Among these, fillers, gap agents, curing accelerators, polymerization initiators, and desiccants (moisture absorbers) are preferred, and fillers and polymerization initiators are more preferred. The inclusion of a filler as an additive can suppress the penetration of moisture and oxygen, and can also provide effects such as reduced volumetric shrinkage during curing, reduced outgassing during curing or heating, improved mechanical strength, and control of thermal conductivity and fluidity. Therefore, including a filler as an additive is highly effective in maintaining stable output in various environments.

[0091] Furthermore, with regard to the output characteristics and durability of a photoelectric conversion element, not only the influence of moisture and oxygen intrusion but also the influence of outgassing generated when the sealing material is cured or heated cannot be ignored. In particular, the influence of outgassing generated when heated has a significant impact on output characteristics when stored in a high-temperature environment. By incorporating a filler, gap agent, or desiccant into the sealing material, these materials themselves can suppress the intrusion of moisture and oxygen, and by reducing the amount of sealing material used, the effect of reducing outgassing can be obtained. Incorporating a filler, gap agent, or desiccant into the sealing material is effective not only during curing but also when storing a photoelectric conversion element in a high-temperature environment.

[0092] The filler is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include inorganic fillers such as crystalline or amorphous silica, silicate minerals such as talc, alumina, aluminum nitride, silicon nitride, calcium silicate, and calcium carbonate. Among these, hydrotalcite is particularly preferred. These may be used alone or in combination of two or more.

[0093] The average primary particle size of the filler is not particularly limited, but is preferably 0.1 μm to 10 μm, more preferably 1 μm to 5 μm. When the average primary particle size of the filler is within the above-mentioned preferred range, the effect of suppressing the penetration of moisture and oxygen can be sufficiently obtained, the viscosity becomes appropriate, and adhesion to the substrate and degassing properties are improved, which is also effective for controlling the width of the sealing portion and workability.

[0094] The content of the filler is preferably 10 parts by mass or more and 90 parts by mass or less, and more preferably 20 parts by mass or more and 70 parts by mass or less, relative to the total amount (100 parts by mass) of the sealing member. When the content of the filler is within the above preferred range, a sufficient effect of suppressing the penetration of moisture and oxygen can be obtained, the viscosity becomes appropriate, and adhesion and workability are also good.

[0095] The gap agent is also called a gap control agent or a spacer agent. By including a gap agent as an additive, it becomes possible to control the gap of the sealing portion. For example, when a sealing member is applied on a first substrate or a first electrode and a second substrate is placed thereon for sealing, the gap of the sealing portion is made equal to the size of the gap agent because the sealing member contains a gap agent, and therefore the gap of the sealing portion can be easily controlled.

[0096] The gap agent is not particularly limited, but is preferably granular, has a uniform particle size, and has high solvent resistance and heat resistance, and can be appropriately selected depending on the purpose. The gap agent is preferably one that has a high affinity with epoxy resin and has a spherical particle shape. Specifically, glass beads, silica fine particles, organic resin fine particles, etc. are preferred. These may be used alone or in combination of two or more. The particle size of the gap agent can be selected according to the gap of the sealing part to be set, but is preferably 1 μm or more and 100 μm or less, and more preferably 5 μm or more and 50 μm or less.

[0097] The polymerization initiator is not particularly limited, but examples include polymerization initiators that initiate polymerization using heat or light. These initiators can be appropriately selected depending on the purpose, and examples include thermal polymerization initiators and photopolymerization initiators. Thermal polymerization initiators are compounds that generate active species such as radicals or cations upon heating, and examples include azo compounds such as 2,2'-azobisbutyronitrile (AIBN) and peroxides such as benzoyl peroxide (BPO). Examples of thermal cationic polymerization initiators include benzenesulfonic acid esters and alkylsulfonium salts. For epoxy resins, photocationic polymerization initiators are preferably used as photopolymerization initiators. When an epoxy resin is mixed with a photocationic polymerization initiator and irradiated with light, the photocationic polymerization initiator decomposes to generate acid, which then polymerizes the epoxy resin, thereby promoting the curing reaction. Photocationic polymerization initiators have the advantages of low volume shrinkage during curing, resistance to oxygen inhibition, and high storage stability.

[0098] Examples of the photocationic polymerization initiator include aromatic diazonium salts, aromatic iodonium salts, aromatic sulfonium salts, methacerone compounds, and silanol-aluminum complexes. Furthermore, photoacid generators that generate acid upon irradiation with light can also be used as polymerization initiators. Examples of photoacid generators include onium salts, such as ionic sulfonium salts and iodonium salts, which act as acids that initiate cationic polymerization and are composed of a cation moiety and an anion moiety. These may be used alone or in combination of two or more.

[0099] The amount of the polymerization initiator added is not particularly limited and may vary depending on the material used, but is preferably 0.5 parts by mass to 10 parts by mass, and more preferably 1 part by mass to 5 parts by mass, relative to the total sealing member (100 parts by mass). When the amount added is within the above preferred range, curing proceeds appropriately, the amount of uncured material remaining can be reduced, and excessive outgassing can be prevented.

[0100] The desiccant (also called moisture absorbent) is a material that physically or chemically adsorbs or absorbs moisture, and by incorporating it into a sealing member, moisture resistance can be further improved and the effects of outgassing can be reduced. The desiccant is not particularly limited and can be appropriately selected depending on the purpose, but particulate desiccants are preferred, and examples include inorganic water-absorbing materials such as calcium oxide, barium oxide, magnesium oxide, magnesium sulfate, sodium sulfate, calcium chloride, silica gel, molecular sieves, and zeolite. Among these, zeolite, which has a high moisture absorption capacity, is preferred. These may be used alone or in combination of two or more types.

[0101] The curing accelerator (also referred to as a curing catalyst) is a material that accelerates the curing rate and is mainly used for thermosetting epoxy resins. The curing accelerator is not particularly limited and can be appropriately selected depending on the purpose. Examples of the curing accelerator include tertiary amines or tertiary amine salts such as DBU (1,8-diazabicyclo(5,4,0)-undecene-7) and DBN (1,5-diazabicyclo(4,3,0)-nonene-5), imidazoles such as 1-cyanoethyl-2-ethyl-4-methylimidazole and 2-ethyl-4-methylimidazole, and phosphines or phosphonium salts such as triphenylphosphine and tetraphenylphosphonium tetraphenylborate. These may be used alone or in combination of two or more.

[0102] The coupling agent is not particularly limited as long as it is a material that has the effect of enhancing molecular bonding strength and can be appropriately selected depending on the purpose. Examples include silane coupling agents. Specific examples include silane coupling agents such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-(2-aminoethyl)3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)3-aminopropylmethyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, N-(2-(vinylbenzylamino)ethyl)3-aminopropyltrimethoxysilane hydrochloride, and 3-methacryloxypropyltrimethoxysilane. These may be used alone or in combination of two or more.

[0103] In this embodiment, for example, a sheet-like adhesive can be used. The sheet-like adhesive is, for example, a sheet on which a resin layer is formed in advance using a sealing resin, and the sheet can be made of glass, a film with high gas barrier properties, or the like. The sheet-like adhesive may also be formed using only a sealing resin. It is also possible to attach the sheet-like adhesive to a sealing film. In this case, it is also possible to provide a hollow portion in the sheet constituting the sheet-like adhesive attached to the sealing film and then attach it to the device.

[0104] When the sealing film is used for sealing, it is disposed opposite the support so as to sandwich the photoelectric conversion device. The base material of the sealing film is not particularly limited in shape, structure, size, and type, and can be appropriately selected depending on the purpose. The sealing film forms a barrier layer on the surface of the base material to prevent the passage of moisture and oxygen, and may be formed on only one side or both sides of the base material.

[0105] The barrier layer may be composed of a material whose main component is, for example, a metal oxide, a metal, a mixture formed of a polymer and a metal alkoxide, etc. Examples of the metal oxide include aluminum oxide, silicon oxide, and aluminum, examples of the polymer include polyvinyl alcohol, polyvinylpyrrolidone, and methyl cellulose, and examples of the metal alkoxide include tetraethoxysilane, triisopropoxyaluminum, 3-glycidoxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-isocyanatopropyltriethoxysilane.

[0106] The barrier layer may be transparent or opaque. The barrier layer may be a single layer or a laminated structure of multiple layers formed from a combination of the above-mentioned materials. The barrier layer may be formed by a known method, such as vacuum film formation (e.g., sputtering), dipping, roll coating, screen printing, spraying, or gravure printing.

[0107] [Wiring] In the photoelectric conversion element 10 (e.g., a solar cell) of this embodiment, it is preferable to connect lead wires (wiring) to the first electrode 12 and the back electrode of the second electrode in order to efficiently extract the current generated by light. The lead wires are connected to the first electrode and the second electrode using, for example, a conductive material such as solder, silver paste, or graphite. The conductive material may be used alone, or two or more types may be mixed or laminated. Furthermore, the portion to which the lead wires are attached may be covered with an acrylic resin or an epoxy resin from the viewpoint of physical protection.

[0108] A lead wire is a general term for an electric wire used to electrically connect a power source, electronic components, etc. in an electric circuit, and examples thereof include vinyl wire and enamel wire.

[0109] The photoelectric conversion element 10 described above has excellent photoelectric conversion characteristics and exhibits the effect of improving durability.

[0110] [Applications] The uses and methods of the photoelectric conversion element 10 of this embodiment are not particularly limited, and can be widely used for, for example, the same purposes as general photoelectric conversion elements (e.g., general solar cells). The photoelectric conversion element (e.g., solar cell) of this embodiment can be applied to a power supply device by combining it with a circuit board that controls the generated current, for example. Examples of devices that use power supply devices include electronic desk calculators and solar-powered radio-controlled watches. The solar cell of this embodiment can also be applied as a power supply device to mobile phones, electronic paper, thermo-hygrometers, etc. Furthermore, it can be used as an auxiliary power source to extend the continuous use time of rechargeable or battery-powered electrical appliances, or for nighttime use by combining it with a secondary battery. It can also be used as a stand-alone power source that does not require battery replacement or power wiring.

[0111] [Solar Cell Module] The solar cell module according to the embodiment includes the photoelectric conversion element 10 of the above-described form. The specific configuration of the solar cell module will be described in the examples.

[0112] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted.

[0113] In the photoelectric conversion element 10, an intermediate layer may be formed between the first electrode 12 and the hole transport layer 13. The intermediate layer preferably uses a single or mixed oxide formed from, for example, an oxide of nickel, copper, aluminum, or the like as a p-type metal oxide semiconductor. The intermediate layer is preferably formed from nickel oxide (NiO). The thickness of the intermediate layer is preferably 1 to 1,000 nm, more preferably 10 to 500 nm. The method for forming the intermediate layer containing nickel oxide (NiO) as a p-type metal oxide semiconductor is not particularly limited, and may be either vacuum film formation such as sputtering or ion plating, or wet film formation such as sol-gel. The average particle size of the nickel oxide microparticles is, for example, 0.2 to 60.0 nm, preferably 1.0 to 30.0 nm, more preferably 1.0 to 10.0 nm, and even more preferably 2.0 to 3.5 nm. By forming an intermediate layer made of a p-type metal oxide semiconductor, it is possible to improve the durability of the photoelectric conversion element while maintaining the photoelectric conversion characteristics without impairing the properties of the hole transport layer 13 and the insulating compound.

[0114] Examples of the present invention will be described below, but the present invention is not limited to the following examples.

[0115] Example 1 A solar cell, which is a photoelectric conversion element, was fabricated (manufactured) as follows (film formation procedure 1).

[0116] On an ITO glass substrate (a 25 mm square glass substrate with a first electrode formed thereon), 1 mL of a DMF solution containing (A-06) (0.1 mmol / L) was applied, and a monolayer (hole transporter in the hole transport layer) was formed on the ITO (first electrode) using a spin coater (3,000 rpm, 30 seconds) and a hot plate (110°C, 10 minutes). Next, 0.1 mL of a solution obtained by diluting an alumina dispersion (alumina average particle size 50 nm, alumina content 20 wt%, and a dispersion medium 2-propanol) 50 times with 2-propanol was added to the hole transporter, and a hole transport layer was formed using a mixture of the hole transport material and the insulating compound using a spin coater (3,000 rpm, 30 seconds) and a hot plate (100°C, 15 minutes). Next, a solution of cesium iodide (0.738 g), formamidine iodide (7.512 g), methylamine bromide (0.905 g), lead iodide (23.888 g), and lead bromide (1.022 g) dissolved in DMF (40.0 mL) and dimethyl sulfoxide (DMSO, 12.0 mL) was spin-coated onto the substrate. Spin-coating was performed at 3000 rpm, and chlorobenzene (0.3 mL) was added dropwise 30 seconds after the start of spin-coating. The substrate was then heated at 150 ° C. for 10 minutes to obtain a perovskite layer (photoelectric conversion layer). Next, ethylenediamine dihydroiodide was applied to a thickness of 0.5 nm (interface layer), C ６０ A photoelectric conversion element was fabricated by vacuum deposition of 20 nm of ZnO (electron transport layer), 8 nm of bathocuproine (BCP) (electron injection layer), and 100 nm of Ag (second electrode). After fabrication, the solar cell characteristics of the 25 mm square photoelectric conversion element were evaluated. Furthermore, to evaluate the variation, 10 solar cells were fabricated under the same conditions, and the solar cell characteristics were evaluated. The best data (best value), average value, and standard deviation of the 10 fabricated samples are shown in Table 1 (this also applies to the following Examples and Comparative Examples).

[0117] The photoelectric conversion characteristics of the photoelectric conversion element prepared in Example 1 were measured in accordance with the output measurement method for silicon crystalline solar cells of JIS C8913:1998. A solar simulator (SMO-250III model manufactured by Bunkoukeiki Co., Ltd.) combined with an air mass filter equivalent to AM1.5G was used to measure the photoelectric conversion characteristics of the photoelectric conversion element prepared in Example 1. The output of the secondary reference Si solar cell was measured at 100 mW / cm. ２ The light intensity was adjusted to 1000 W and used as a measurement light source, and the IV curve characteristics were measured using a source meter (Keithley Instruments Inc., 2400-type general-purpose source meter) while irradiating a test sample of a perovskite solar cell (the photoelectric conversion element produced in Example 1). The short-circuit current (Isc), open-circuit voltage (Voc), fill factor (FF), short-circuit current density (Jsc), and photoelectric conversion efficiency (PCE) obtained from the IV curve characteristics measurement were determined. In the following examples and comparative examples, the solar cell characteristics were evaluated in the same manner.

[0118] Equation 1: Short-circuit current density (Jsc; mA / cm ２ )=Isc(mA) / Effective light-receiving surface S(cm ２ ) Equation 2: Photoelectric conversion efficiency (PCE; %) = Voc (V) × Jsc (mA / cm ２ ) x FF x 100 / 100 (mW / cm ２ )

[0119] Example 2 A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that a solution prepared by diluting an alumina dispersion (average alumina particle size of 50 nm, alumina content of 20 wt %, and a dispersion medium of 2-propanol) as the insulating compound in Example 1 50 times with 2-propanol was used instead of a solution prepared by diluting an alumina dispersion (average alumina particle size of 50 nm, alumina content of 20 wt %, and a dispersion medium of 2-propanol) 30 times with 2-propanol, and the photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 1 below.

[0120] Example 3 A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that a solution prepared by diluting an alumina dispersion (average alumina particle size of 50 nm, alumina content of 20 wt %, and a dispersion medium of 2-propanol) as the insulating compound in Example 1 50 times with 2-propanol was used instead of a solution prepared by diluting an alumina dispersion (average alumina particle size of 50 nm, alumina content of 20 wt %, and a dispersion medium of 2-propanol) 100 times with 2-propanol, and the photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 1 below.

[0121] Example 4 A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that a DMF solution containing (A-15) (0.1 mmol / L) was used instead of the DMF solution containing (A-06) (0.1 mmol / L) in Example 1, and the photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 1 below.

[0122] Example 5 A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that a DMF solution containing (A-16) (0.1 mmol / L) was used instead of the DMF solution containing (A-06) (0.1 mmol / L) in Example 1, and the photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 1 below.

[0123] Example 6 A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that the DMF solution in which (A-06) (0.1 mmol / L) was dissolved in Example 1 was changed to a DMF solution in which (A-06) (0.1 mmol / L) and 4-hydroxyphenylphosphonic acid (0.2 mmol / L) were dissolved, and the photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 1 below.

[0124] Example 7 A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that a solution obtained by diluting an alumina dispersion (alumina average particle size 50 nm, alumina content 20 wt %, dispersion medium 2-propanol) as the insulating compound in Example 1 50 times with 2-propanol was replaced with a solution obtained by diluting a silica dispersion (silica average particle size 150 nm, silica content 5 wt %, dispersion medium ethanol) 8 times with 2-propanol, and the photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 1 below.

[0125] Example 8 A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that a solution prepared by diluting an alumina dispersion (alumina average particle size 50 nm, alumina content 20 wt %, dispersion medium 2-propanol) as the insulating compound in Example 1 50 times with 2-propanol was used instead of a solution prepared by diluting a ceria dispersion (ceria average particle size 50 nm, ceria content 20 wt %, dispersion medium 2.5 wt % acetic acid aqueous solution) 50 times with 2-propanol. The photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 1 below.

[0126] Example 9 A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that a solution prepared by diluting an alumina dispersion (alumina average particle size 50 nm, alumina content 20 wt %, dispersion medium 2-propanol) as the insulating compound in Example 1 50 times with 2-propanol was used instead of a solution prepared by diluting an yttria dispersion (yttria average particle size 100 nm, yttria content 10 wt %, dispersion medium 2-propanol) 25 times with 2-propanol, and the photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 1 below.

[0127] Example 10 A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that a solution prepared by diluting an alumina dispersion (alumina average particle size of 50 nm, alumina content of 20 wt %, dispersion medium of 2-propanol) as the insulating compound in Example 1 50 times with 2-propanol was used instead of a solution prepared by diluting a barium titanate dispersion (barium titanate average particle size of 50 nm, barium titanate content of 5 wt %, dispersion medium of 2-propanol) 12.5 times with 2-propanol, and the photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 1 below.

[0128] Example 11: A solar cell, a photoelectric conversion element, was fabricated (manufactured) as follows (film formation procedure 2). On the ITO of an ITO glass substrate (a glass substrate serving as a support on which a first electrode was formed, 25 mm square), 0.1 mL of a solution prepared by diluting an alumina dispersion (a dispersion containing 20 wt% alumina and 2-propanol as a dispersion medium) 50 times with 2-propanol was placed, and the substrate was treated with a spin coater (3,000 rpm, 30 seconds) and then dried on a hot plate (100°C, 15 minutes). Next, 1 mL of a DMF solution containing (A-06) (0.1 mmol / L) was placed, and a hole transport layer was formed using a spin coater (3,000 rpm, 30 seconds) and a hot plate (110°C, 10 minutes). Next, a solution of cesium iodide (0.738 g), formamidine iodide (7.512 g), methylamine bromide (0.905 g), lead iodide (23.888 g), and lead bromide (1.022 g) dissolved in DMF (40.0 mL) and dimethyl sulfoxide (DMSO, 12.0 mL) was spin-coated onto the substrate. Spin-coating was performed at 3000 rpm, and chlorobenzene (0.3 mL) was added dropwise 30 seconds after the start of spin-coating. The substrate was then heated at 150 ° C. for 10 minutes to obtain a perovskite layer (photoelectric conversion layer). Next, ethylenediamine dihydroiodide was applied to a thickness of 0.5 nm (interface layer), C ６０A 20 nm thick film of ZnO (electron transport layer), 8 nm thick bathocuproine (BCP) (electron injection layer), and 100 nm thick Ag (second electrode) were vacuum-deposited to prepare a photoelectric conversion element. After fabrication, the solar cell characteristics of the 25 mm square photoelectric conversion element were evaluated. The performance is shown in Table 1.

[0129] Example 12 A photoelectric conversion element was produced (manufactured) in the same manner as in Example 11, except that the alumina dispersion (a dispersion having an average alumina particle size of 50 nm, an alumina content of 20 wt %, and 2-propanol as a dispersion medium) in Example 11 diluted 50 times with 2-propanol was replaced with a silica dispersion (a dispersion having an average silica particle size of 150 nm, a silica content of 5 wt %, and ethanol as a dispersion medium) diluted 8 times with 2-propanol, and the photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 1 below.

[0130] Example 13 A solar cell, which is a photoelectric conversion element, was prepared (manufactured) as follows (Film Formation Procedure 3). On the ITO of an ITO glass substrate (a glass substrate serving as a support having a first electrode formed thereon, 25 mm square), 1 mL of a solution obtained by diluting an alumina dispersion (a dispersion having an average alumina particle size of 50 nm, an alumina content of 20 wt %, and 2-propanol as a dispersion medium) 50 times with DMF and a DMF solution in which (A-15) (0.1 mmol / L) had been dissolved, mixed at a volume ratio of 1:1, was placed, and a hole transport layer was formed using a spin coater (3,000 rpm, 30 seconds) and a hot plate (100°C, 10 minutes). Next, a solution of cesium iodide (0.738 g), formamidine iodide (7.512 g), methylamine bromide (0.905 g), lead iodide (23.888 g), and lead bromide (1.022 g) dissolved in DMF (40.0 mL) and dimethyl sulfoxide (DMSO, 12.0 mL) was spin-coated onto the substrate. Spin-coating was performed at 3000 rpm, and chlorobenzene (0.3 mL) was added dropwise 30 seconds after the start of spin-coating. The substrate was then heated at 150 ° C. for 10 minutes to obtain a perovskite layer (photoelectric conversion layer). Next, ethylenediamine dihydroiodide was applied to a thickness of 0.5 nm (interface layer), C ６０A 20 nm thick film of ZnO (electron transport layer), 8 nm thick bathocuproine (BCP) (electron injection layer), and 100 nm thick Ag (second electrode) were vacuum-deposited to prepare a photoelectric conversion element. After fabrication, the solar cell characteristics of the 25 mm square photoelectric conversion element were evaluated. The performance is shown in Table 1.

[0131] Example 14 A photoelectric conversion element was prepared (manufactured) in the same manner as in Example 1, except that the solution obtained by diluting an alumina dispersion (alumina average particle size 50 nm, alumina content 20 wt%, dispersion medium 2-propanol) as the insulating compound in Example 1 50 times with 2-propanol was replaced with a solution obtained by diluting an alumina dispersion (alumina average particle size 50 nm, alumina content 20 wt%, dispersion medium 2-propanol) 50 times with 2-propanol and a solution obtained by diluting a silica dispersion (silica average particle size 150 nm, silica content 5 wt%, dispersion medium ethanol) 8 times with 2-propanol, mixed in a mass ratio of 1:1. The photoelectric conversion efficiency was measured. The solar cell characteristics results are shown in Table 1 below.

[0132] Example 15 A photoelectric conversion element was prepared (manufactured) in the same manner as in Example 1, except that the solution obtained by diluting an alumina dispersion (average alumina particle size of 50 nm, alumina content of 20 wt%, dispersion medium of 2-propanol) as the insulating compound in Example 1 50 times with 2-propanol was replaced with a solution obtained by mixing an alumina dispersion (average alumina particle size of 50 nm, alumina content of 20 wt%, dispersion medium of 2-propanol) 50 times with 2-propanol and an yttria dispersion (average yttria particle size of 100 nm, yttria content of 10 wt%, dispersion medium of 2-propanol) 25 times with 2-propanol at a volume ratio of 1:1. The photoelectric conversion efficiency was measured. The solar cell characteristics results are shown in Table 1 below.

[0133] Comparative Example 1 A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that a solution prepared by diluting the alumina dispersion (alumina average particle size 50 nm, alumina content 20 wt %, dispersion medium 2-propanol) as the insulating compound in Example 1 50 times with 2-propanol was not used, and the photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 1 below.

[0134] Comparative Example 2 A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that the alumina dispersion (alumina average particle size 50 nm, alumina content 20 wt %, dispersion medium 2-propanol) used as the insulating compound in Example 1 was diluted 50 times with 2-propanol, and the solution was changed to a solution of aluminum-doped zinc oxide dispersion (aluminum-doped zinc oxide (also referred to as AZO) dispersion medium 16 nm, AZO content 2.5 wt %, dispersion medium 2-propanol) diluted 6.25 times with 2-propanol, and the photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 1 below.

[0135] Comparative Example 3 A photoelectric conversion element was prepared (manufactured) in the same manner as in Example 11, except that a solution prepared by diluting an alumina dispersion (average alumina particle size of 50 nm, alumina content of 20 wt %, and a dispersion medium of 2-propanol) as the insulating compound in Example 11 50 times with 2-propanol was replaced with a solution prepared by diluting an aluminum-doped zinc oxide dispersion (average AZO particle size of 16 nm, AZO content of 2.5 wt %, and a dispersion medium of 2-propanol) 6.25 times with 2-propanol, and the photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 1 below.

[0136] Comparative Example 4 A photoelectric conversion element was produced (manufactured) in the same manner as in Example 13, except that a solution prepared by diluting an alumina dispersion (average alumina particle size of 50 nm, alumina content of 20 wt %, and a dispersion medium of 2-propanol) as the insulating compound in Example 13 50 times with DMF was used instead of a solution prepared by diluting an aluminum-doped zinc oxide dispersion (average AZO particle size of 16 nm, AZO content of 2.5 wt %, and a dispersion medium of 2-propanol) 6.25 times with DMF, and the photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 1 below.

[0137]

[0138] From Table 1, a comparison between Example 1 and Comparative Example 1 shows that by using a material in which a hole transport material and an insulating compound are mixed in the hole transport layer, the short-circuit current density (Jsc) in particular increases, and high efficiency is obtained. Furthermore, from Examples 1 to 3, it is clear that high efficiency can be obtained even if the concentration of the insulating compound changes, and from Examples 7 to 10, it is clear that a highly efficient solar cell can be provided even if the type of insulating compound is different. Furthermore, from Examples 1 and 4 to 5, it is clear that a high-output solar cell can be provided when a different type of hole transport material is combined with an insulating compound. Furthermore, from Examples 1 and 11 to 13, it is clear that high output can be achieved even if the film formation method is changed. From Example 1 and Comparative Example 2, Example 11 and Comparative Example 3, and Example 13 and Comparative Example 4, it is clear that a high-output solar cell can be obtained when the material combined with the hole transport material is an insulating compound, but a conductive compound (AZO is usually 10 ―３ It can be seen that when combined with a high resistance value (Ω / □), only low efficiency can be provided. Furthermore, it is clear that the embodiment of the present invention exhibits excellent effects not only in terms of high solar cell characteristics but also in terms of the variation (standard deviation) of solar cell characteristics when ten solar cells are fabricated.

[0139] Example 16: A 15-nm nickel oxide (NiO) film was formed on the ITO of an ITO glass substrate (a 25 mm square glass substrate with a first electrode formed thereon). Next, 1 mL of a DMF solution containing (A-06) (0.1 mmol / L) was applied, and a monolayer (hole transport layer) was formed on the NiO using a spin coater (3,000 rpm, 30 seconds) and a hot plate (110°C, 10 minutes). Next, a hole transport layer was formed using a solution prepared by diluting an alumina dispersion (Sigma-Aldrich, 702129, 50 nm, 20 wt %, 2-propanol dispersion) 50 times with 2-propanol using a spin coater (3,000 rpm, 30 seconds) and a hot plate (100°C, 15 minutes). Next, a solution of cesium iodide (0.738 g), formamidine iodide (7.512 g), methylamine bromide (0.905 g), lead iodide (23.888 g), and lead bromide (1.022 g) dissolved in DMF (40.0 mL) and dimethyl sulfoxide (DMSO, 12.0 mL) was spin-coated onto the substrate. Spin-coating was performed at 3000 rpm, and chlorobenzene (0.3 mL) was added dropwise 30 seconds after the start of spin-coating. The substrate was then heated at 150 ° C. for 10 minutes to obtain a perovskite layer (photoelectric conversion layer). Next, ethylenediamine dihydroiodide was applied to a thickness of 0.5 nm (interface layer), C ６０ A photoelectric conversion element was fabricated by vacuum deposition of 20 nm of ZnO (electron transport layer), 8 nm of bathocuproine (BCP) (electron injection layer), and 100 nm of Ag (second electrode). After fabrication, the solar cell characteristics of the 25 mm square photoelectric conversion element were evaluated. The performance is shown in Table 1. In addition, to evaluate the variation, 10 solar cells were fabricated under the same conditions, and the solar cell characteristics were evaluated to determine the average value and standard deviation. The values ​​are shown in Table 2.

[0140] [Example 17] A photoelectric conversion element was produced (manufactured) in the same manner as in Example 16, except that NiO (15 nm film thickness) was used instead of NiO (25 nm film thickness), and the photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 2 below.

[0141] Example 18 A photoelectric conversion element was produced (manufactured) in the same manner as in Example 16, except that NiO (15 nm film thickness) was changed to NiO (50 nm film thickness), and the photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 2 below.

[0142] Example 19 A photoelectric conversion element was produced (manufactured) in the same manner as in Example 16, except that NiO (15 nm film thickness) was used instead of NiO (70 nm film thickness), and the photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 2 below.

[0143] [Example 20] The NiO (15 nm film thickness) in Example 16 was replaced with CuAlO ２ A photoelectric conversion element was produced (manufactured) in the same manner as in Example 16, except that the thickness was changed to (15 nm film thickness), and the photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 2 below.

[0144] [Example 21] The NiO (15 nm film thickness) in Example 16 was replaced with CuAlO ２ A photoelectric conversion element was produced (manufactured) in the same manner as in Example 16, except that the thickness was changed to (30 nm film thickness), and the photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 2 below.

[0145] [Example 22] The NiO (15 nm film thickness) in Example 16 was replaced with CuAlO ２ A photoelectric conversion element was produced (manufactured) in the same manner as in Example 16, except that the thickness was changed to (50 nm film thickness), and the photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 2 below.

[0146] [Example 23] The NiO (15 nm film thickness) in Example 16 was replaced with CuAlO ２ A photoelectric conversion element was produced (manufactured) in the same manner as in Example 16, except that the thickness was changed to 70 nm (film thickness), and the photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 2 below.

[0147] [Example 24] The NiO (15 nm film thickness) in Example 16 was replaced with NiAlO ２ A photoelectric conversion element was produced (manufactured) in the same manner as in Example 16, except that the thickness was changed to (15 nm film thickness), and the photoelectric conversion efficiency was measured. The solar cell characteristic results are shown in Table 2 below.

[0148]

[0149] As described above, this example confirmed that by using the hole transport material and insulating compound of the above-described embodiment in the hole transport layer, not only can the solar cell characteristics be improved but also the variation in characteristics can be reduced.

[0150] [Solar Cell Module] A first electrode 42 was formed on the surface of a glass substrate 41, and the first electrode 42 was patterned into the shape shown in FIG. 2 using a laser processing device. A monomolecular hole transport layer was formed on this first electrode 42, and a perovskite layer was further obtained as a photoelectric conversion layer. Next, an electron transport layer was formed by vacuum deposition. The photoelectric conversion layer (perovskite layer) was then etched using a laser processing device to form a pattern of the photoelectric conversion layer (perovskite layer) 43 as shown in FIG. 3. Finally, 70 nm of Ag was formed by vacuum deposition, and a second electrode 44 was etched using a laser processing device to obtain a photoelectric conversion module (perovskite solar cell module) with the shape shown in FIGS. 4 and 5.

[0151] The present invention has been described above using embodiments and examples. However, the present invention is not limited to the embodiments and examples described above, and can be arbitrarily and appropriately combined, modified, or selected and adopted as needed within the scope of the gist of the present invention.

[0152] As described above, the photoelectric conversion element of the present invention is useful, for example, as a solar cell. The application and method of use of the photoelectric conversion element of the present invention are not particularly limited, and for example, the application and method are similar to those of a general photoelectric conversion element (for example, a general solar cell), and the photoelectric conversion element can be applied to a wide range of fields. CROSS-REFERENCE TO RELATED APPLICATIONS

[0153] This application claims priority based on Japanese Patent Application No. 2023-198632, filed with the Japan Patent Office on November 22, 2023, the entire disclosure of which is incorporated herein by reference in its entirety.

[0154] REFERENCE SIGNS LIST 10 Photoelectric conversion element 11 Support 12 First electrode 13 Hole transport layer 14 Photoelectric conversion layer 15 Electron transport layer 16 Second electrode

Claims

1. A photoelectric conversion element comprising a first electrode, a hole transport layer, a photoelectric conversion layer, and a second electrode, which are directly or indirectly stacked in this order, the photoelectric conversion layer contains a perovskite compound, and the hole transport layer contains an insulating compound and a compound represented by the following chemical formula (I) in contact with the main surface of the first electrode on the photoelectric conversion layer side. １ - (L １ -X １ ) n. . . (I) In the above chemical formula (I), Ar １ is a structure containing an aromatic ring, and the aromatic ring may contain a heteroatom, １ Is, -L １ -X １ n is an integer of 1 or more, and when n is 2 or more, -L １ -X １ The structures represented by the formula (I) may be the same or different from each other. １ is Ar １ and X １ X is a divalent linking group or a single bond. １ is a group capable of forming a chemical bond or a hydrogen bond with the first electrode.

2. The photoelectric conversion element according to claim 1, wherein the hole transport layer contains a compound represented by the following chemical formula (II): 1 -L ２ -X ２ (II) A 1 is an atomic group containing one or more substituents or structures selected from the group consisting of an alkoxy group, a hydroxy group, a carboxy group, a dihydroxyphosphoryl group, a dialkylphosphoryl group, a hydroxysulfonyl group, an amino group, a monoalkylamino group, a dialkylamino group, a monoarylamino group, a diarylamino group, a monoalkylaminocarbonyl group, a dialkylaminocarbonyl group, an alkylcarbonyloxy group, an alkoxycarbonyl group, an aminocarbonyl group, an aminocarbonylamino group, an alkylcarbonylamino group, an alkylsulfonylamino group, an aminosulfonyl group, and a nitrogen-containing heterocyclic group. ２ A 1 and X ２ X is a divalent linking group or a single bond. ２ is a group capable of forming a chemical bond or a hydrogen bond with the first electrode.

3. The photoelectric conversion element according to claim 1 or 2, wherein the compound represented by the chemical formula (I) forms a monolayer.

4. The photoelectric conversion element according to claim 1 or 2, wherein the insulating compound is at least one selected from the group consisting of metal oxides, metal nitrides, insulating organic compounds, and organic-inorganic hybrid compounds.

5. The photoelectric conversion element according to claim 4, wherein the insulating compound is in a particulate form.

6. The photoelectric conversion element according to claim 5, wherein the insulating compound has an average particle size in the range of 1 to 200 nm.

7. X in the above chemical formula (I) １ are dihydroxyphosphoryl groups (-P=O(OH) ２ ), carboxy group (-COOH), sulfo group (-SO ３ H), boronic acid group (-B(OH) ２ ), trihalogenated silyl group (-SiX ３ , where X is a halo group), a trialkoxysilyl group (-Si(OR) ３ 3. The photoelectric conversion element according to claim 1, wherein R is an alkyl group, a trihydroxysilyl group, and a dialkylphosphoryl group.

8. X in the above chemical formula (II) ２ each independently represents a dihydroxyphosphoryl group (-P=O(OH) ２ ), carboxy group (-COOH), sulfo group (-SO ３ H), boronic acid group (-B(OH) ２ ), trihalogenated silyl group (-SiX ３ , where X is a halo group), a trialkoxysilyl group (-Si(OR) ３ 3. The photoelectric conversion element according to claim 2, wherein R is an alkyl group, a trihydroxysilyl group, and a dialkylphosphoryl group.

9. The photoelectric conversion element according to claim 1 or 2, wherein the perovskite compound is an organic-inorganic perovskite compound.

10. The photoelectric conversion element according to claim 1 or 2, wherein the mass ratio of the mass (m1) of the compound represented by the chemical formula (I) to the mass (m2) of the insulating compound satisfies the relationship of the following formula (A): m1 / m2=1 / 10 to 1 / 20000 (A).

11. The photoelectric conversion element according to claim 1 or 2, wherein an intermediate layer containing nickel oxide is formed between said first electrode and said hole transport layer.

12. A solar cell module comprising the photoelectric conversion element according to claim 1 or 2.

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