Photoelectric conversion elements and photoelectric conversion devices

Abstract

The present invention provides a photoelectric conversion element (1) in which defects of a crystal having a perovskite structure are protected, and it has improved leakage resistance and improved conversion efficiency. The photoelectric conversion element (1) includes: a first electrode (7); a second electrode (3); and a photoelectric conversion layer (5) disposed between the first electrode (7) and the second electrode (3), wherein the photoelectric conversion layer comprises a crystal having a perovskite structure. The photoelectric conversion element (1) has a charge transport layer (6) between the photoelectric conversion layer (5) and the first electrode (7), the charge transport layer (6) comprising a cyclic conjugated compound in which a plurality of pyrrole rings are conjugated, and an aliphatic resin having at least one functional group selected from the group consisting of hydroxyl and carboxyl groups.

Description

Technical Field

[0001] This invention relates to photoelectric conversion elements and photoelectric conversion devices. Background Technology

[0002] To address the depletion of fossil fuels and the environmental problems caused by their use, research is actively underway on renewable and clean alternative energy sources such as solar, wind, and hydropower. In particular, there is increasing interest in solar cells, which directly convert sunlight into electricity. As used in this paper, "solar cell" refers to a battery that generates current and voltage using the photovoltaic effect, in which light energy is absorbed from sunlight to produce electrons and holes.

[0003] Currently, NP diode-based monocrystalline silicon (Si) solar cells with a light conversion efficiency exceeding 20% ​​are widely known and practically used in solar power generation. However, solar cells require high-temperature processing steps, and the materials themselves are expensive, resulting in high cost per unit of electricity. Furthermore, there are supply issues regarding silicon resources.

[0004] Meanwhile, solar cells using organic materials (hereinafter referred to as "organic solar cells") do not require high-temperature processing steps and can be manufactured as sheet substrates using a so-called roll-to-roll method. Therefore, cost reduction is expected. However, for the practical application of organic solar cells, further improvements in power generation efficiency and durability are desired. In particular, the development of perovskite-type solar cells, which incorporate crystals with a perovskite structure as the photoelectric conversion layer, is being promoted for practical application because these cells exhibit excellent photoelectric conversion performance.

[0005] For example, Patent Document 1 describes an improvement in conversion efficiency and durability by incorporating an insulating polymer and a hole transport material into the hole transport layer to suppress delamination between the hole transport layer and the anode. Non-Patent Document 1 describes an improvement in conversion efficiency by introducing polymethyl methacrylate (PMMA) as a leakage prevention layer into the upper layer of the perovskite to suppress shunt leakage. Non-Patent Document 2 describes an improvement in conversion efficiency by incorporating copper phthalocyanine and a conductive polymer into the hole transport layer.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2018-170382

[0009] Non-patent literature

[0010] Non-patent literature 1: F. Wang et al., J. Phys. Chem. C, 2017, 121, 1562

[0011] Non-patent literature 2: Q. Hu et al., Sol. RRL, 2019, 3, 1800264 Summary of the Invention

[0012] The problem the invention aims to solve

[0013] According to the research conducted by the inventors of the present invention, in the various photoelectric conversion elements described in Patent Document 1 and Non-Patent Documents 1 and 2, although the suppression of shunt leakage is maintained, there are problems in achieving further improvement in conversion efficiency.

[0014] Therefore, the object of the present invention is to provide a photoelectric conversion element in which defects of a crystal having a perovskite structure are protected, and leakage resistance and conversion efficiency are improved. Furthermore, the object of the present invention is to provide a photoelectric conversion device with improved leakage resistance and conversion efficiency.

[0015] Solution for solving the problem

[0016] The above-mentioned objective is achieved by the following invention. Specifically, the photoelectric conversion element according to the invention comprises: a first electrode; a second electrode; and a photoelectric conversion layer disposed between the first and second electrodes, the photoelectric conversion layer comprising a crystal having a perovskite structure, wherein the photoelectric conversion element further comprises a charge transport layer between the photoelectric conversion layer and the first electrode, the charge transport layer comprising: a cyclic conjugated compound wherein a plurality of pyrrole rings are linked by conjugated bonds; and an aliphatic resin having at least one functional group selected from the group consisting of hydroxyl and carboxyl groups.

[0017] The effects of the invention

[0018] According to the present invention, it is possible to provide a photoelectric conversion element with improved leakage resistance and conversion efficiency. Attached Figure Description

[0019] [ Figure 1 [Illustrated cross-sectional view of a photoelectric conversion element according to a first embodiment of the present invention in the thickness direction.]

[0020] [ Figure 2 [Illustrated cross-sectional view of a photoelectric conversion element according to a second embodiment of the present invention in the thickness direction.]

[0021] [ Figure 3 [This is a perspective view schematically illustrating an embodiment of a movable body including the photoelectric conversion element of the present invention.]

[0022] [ Figure 4 [This is a perspective view schematically illustrating an embodiment of a building material including the photoelectric conversion element of the present invention.] Detailed Implementation

[0023] The photoelectric conversion element of the present invention includes a first electrode, a second electrode, and a photoelectric conversion layer disposed between the first electrode and the second electrode. The photoelectric conversion layer comprises a crystal having a perovskite structure, and the photoelectric conversion element includes a charge transport layer between the photoelectric conversion layer and the first electrode. The charge transport layer comprises: a cyclic conjugated compound wherein a plurality of pyrrole rings are covalently bonded; and an aliphatic resin having at least one functional group selected from the group consisting of hydroxyl and carboxyl groups.

[0024] As a result of their research, the inventors of this invention discovered that when the aforementioned charge transport layer is included, a photoelectric conversion element with excellent leakage resistance and conversion efficiency is obtained. The detailed reasons why a photoelectric conversion element with high stability can be obtained in this invention are not yet clear, but are speculated as follows.

[0025] By using a cyclic conjugated compound in which multiple pyrrole rings are covalently bonded as a charge transport material to form a film, high hole transport capability is exhibited. Furthermore, in previous studies conducted by the inventors, it was hypothesized that when the photoelectric conversion layer contains a crystal with a perovskite structure, submicron-level unevenness is generated on its surface. By filling such unevenness with pigment particles formed from phthalocyanine compounds, the interfacial bonding is stabilized, and high photoelectric conversion efficiency can be obtained. However, it was found that in some cases, leakage caused by crystallization defects or deterioration of the perovskite-structured crystal cannot be suppressed by filling with pigments containing phthalocyanine compounds. Further, in the inventors' research, it was found that in the photoelectric conversion element described in Non-Patent Document 1, since the formation of an insulating resin electrode film is required from the viewpoint of conductivity, it is difficult to completely cover the perovskite-structured crystal with large defect sites, leaving room for further improvement in leakage resistance.

[0026] Therefore, in this invention, by forming a charge transport layer comprising a cyclic conjugated compound containing a plurality of covalently bonded pyrrole rings and an aliphatic resin having at least one functional group selected from the group consisting of hydroxyl and carboxyl groups, improved leakage resistance and conversion efficiency can be achieved. The inventors of this invention hypothesize that the aliphatic resin improves leakage resistance by suppressing the increase in the series resistance of the membrane through electronic interactions between the cyclic conjugated compound and the aliphatic resin, which contributes to improved conversion efficiency.

[0027] The inventors of this invention hypothesize that combining an aliphatic resin having at least one functional group selected from the group consisting of hydroxyl and carboxyl groups with a cyclic conjugated compound having multiple pyrrole rings covalently bonded therein can contribute to improved leakage resistance and conversion efficiency. This hypothesizes that when multiple pyrrole rings are covalently bonded to form a cyclic conjugated compound, the π-electron cloud expands significantly in a direction perpendicular to the large cyclic surface, thereby increasing electronic interactions with other molecules. Through the electronic interactions between the cyclic conjugated compound, which readily generates electronic interactions, and the functional groups of the aliphatic resin, an electron shift occurs within the cyclic conjugated compound, thus increasing the carrier density.

[0028] As a result, it is speculated that the conductivity of the cyclic conjugated compound itself, as a charge transport material, increases, and this increase contributes to improved leakage resistance and conversion efficiency. Furthermore, it has been found that because the crystal defects with the perovskite structure reach tens to hundreds of nanometers, the charge transport layer still contributes to improved leakage resistance and conversion efficiency even when a hole transport layer or insulating layer of tens of nanometers thickness is introduced between the charge transport layer and the photoelectric conversion layer of the present invention. From the viewpoint of leakage resistance, it is particularly preferable to have the charge transport layer in contact with the photoelectric conversion layer.

[0029] Specific examples of hole transport layers or insulating layers that can be inserted between the charge transport layer and the photoelectric conversion layer of the present invention include: sodium chloride, sodium iodide, potassium iodide, rubidium iodide, cesium acetate, copper bromide (I), copper iodide (I), nickel chloride (II), zinc iodide, germanium dioxide, aluminum acetylacetonate, europium acetylacetonate (III), 1,8-diaminooctane dihydroiodide, 1,4-butanediamine dihydroiodide, hexylamine hydrobromide, n-octylamine hydrobromide, 2-phenylethylammonium iodide, ethylenediamine dihydroiodide, sodium fluoride, cesium chloride, methylammonium chloride, lead thiocyanate (II), lead acetate (II), potassium chloride, niobium fluoride (V), choline chloride, L-α-phosphatidylcholine, fullerene, and methyl phenyl C61-butyrate (PCBM). ((6,6)-phenylC61butyric acid methyl)), iodopentafluorobenzene, F4TCNQ, thiophene, pyridine, pentafluorobenzyl bromide, (3-mercaptopropyl)trimethoxysilane, thiourea, benzylamine, hexamethylenetetramine, N-(3-aminopropyl)-2-pyrrolidone, theophylline, caffeine, 2-aminoethanesulfonamide hydrochloride, tri-n-octylphosphine oxide, graphene oxide, poly(3-hexylthiophene-2,5-diyl), poly(4-vinylpyridine), polyethylene oxide, polyvinylpyrrolidone, and poly(methyl methacrylate). Among them, the following are particularly preferred: sodium chloride, potassium iodide, rubidium iodide, cesium acetate, nickel(II) chloride, aluminum acetylacetonate, n-octylamine hydrobromide, 2-phenylethylammonium iodide, sodium fluoride, cesium chloride, methylammonium chloride, potassium chloride, niobium(V) fluoride, thiophene, pyridine, trimethoxysilane, thiourea, benzylamine, theophylline, poly(4-vinylpyridine), and poly(methyl methacrylate).

[0030] From the perspective of leak resistance, the molecular weight of aliphatic resin is preferably 10,000 or higher.

[0031] Furthermore, from the viewpoint of interaction with cyclic conjugated compounds, the functional groups of aliphatic resins having at least one functional group selected from the group consisting of hydroxyl and carboxyl groups preferably further include at least one functional group selected from the group consisting of carbonyl, ester (ester bond), ether (ether bond), carboxyl, methoxy, amino, sulfonyl, aldehyde, amide (amide bond) and thioether.

[0032] From the viewpoint of leakage resistance and conversion efficiency, the content of a cyclic conjugated compound in which multiple pyrrole rings are covalently bonded is preferably 5 to 30% by mass, more preferably 8 to 20% by mass, relative to an aliphatic resin having at least one functional group selected from the group consisting of hydroxyl and carboxyl groups.

[0033] In this invention, an aliphatic resin having at least one functional group selected from the group consisting of hydroxyl and carboxyl groups refers to a resin having such functional group in either the main chain or the side chain. This functional group is preferably contained at a position other than the end of the main chain. Furthermore, hydroxyl and carboxyl groups are Lewis basic functional groups.

[0034] Preferred specific examples of aliphatic resins used in this invention include: polyvinyl alcohol, polyacrylic acid, poly(2-propylacrylic acid), poly(4-vinylphenol), polyvinyl butyral, poly(butadiene / maleic acid), poly(2-hydroxyethyl methacrylate), and poly(methyl methacrylate / methacrylic acid). Among these, from the viewpoint of electronic interactions, polyvinyl alcohol, polyacrylic acid, polyvinyl butyral, poly(butadiene / maleic acid), poly(2-hydroxyethyl methacrylate), and poly(methyl methacrylate / methacrylic acid) are particularly preferred.

[0035] From the viewpoint of expanding the π-electron cloud that serves as the starting point of the interaction, the cyclic conjugated compounds in which multiple pyrrole rings are covalently bonded are preferably porphyrin compounds or phthalocyanine compounds, more preferably phthalocyanine compounds. The phthalocyanine compounds may have a central element, and examples of central elements include Ga, Cu, Ti, Zn, Si, V, Pb, and Pt. Among these, Ga is preferred from the viewpoint of electronic interaction with aliphatic resins having at least one functional group selected from the group consisting of hydroxyl and carboxyl groups, and hydroxygallium phthalocyanine compounds are particularly preferred from the viewpoint of interaction with this functional group.

[0036] From the viewpoint of the mixed state of the membrane, the glass transition temperature of the aliphatic resin having at least one functional group selected from the group consisting of hydroxyl and carboxyl groups is preferably 95°C or less.

[0037] Specific examples of the porphyrin compounds of the present invention include the following compounds.

[0038] [Chemical Formula 1]

[0039]

[0040] [Chemical Formula 2]

[0041]

[0042] In equations (P-1) and (P-2), R1~R 12 Each of these groups independently represents either hydrogen or an organic group, including aromatic groups that may have substituents or aliphatic groups that may have substituents.

[0043] R1~R 12Each of these groups independently represents hydrogen, methyl, ethyl, propyl, isopropyl, butyl, octyloxy, butoxy, halogen atom, phenyl, phenoxy, carboxyphenyl, benzenesulfonic acid, hydroxyphenyl, dihydroxyphenyl, trihydroxyphenyl, methoxyphenyl, dimethoxyphenyl, trimethoxyphenyl, methylphenyl, dimethylphenyl, trimethylphenyl, pyridyl, aminophenyl, sodium sulfonate, 4-cumylphenoxy, sulfonic acid, phenylthio, tert-butyl, hydroxy, carbonyl, methoxy, amino, sulfonyl, or aldehyde. In formulas (P-1) and (P-2), X represents an inorganic atom including a metal atom, with preferred examples including Ga, GaOH, GaCl, TiO, Ti, Si, V, Pb, SiCl2, Cu, Zn, Pd, Pb, Ni, Pt, Co, MnCl, FeCl, VO, and RuCO.

[0044] Specific examples of phthalocyanine compounds of the present invention include the following compounds.

[0045] [Chemical Formula 3]

[0046]

[0047] [Chemical Formula 4]

[0048]

[0049] [Chemical Formula 5]

[0050]

[0051] In equations (P-3) and (P-4) above, R 13 ~R 28 Each independently represents a hydrogen atom or an organic group, including aromatic groups that may have substituents or aliphatic groups that may have substituents. R 13 ~R 28 Each group preferably represents a hydrogen atom, methyl, ethyl, propyl, isopropyl, butyl, octyloxy, butoxy, halogen atom, phenyl, phenoxy, carboxyphenyl, benzenesulfonic acid group, hydroxyphenyl, dihydroxyphenyl, trihydroxyphenyl, methoxyphenyl, dimethoxyphenyl, trimethoxyphenyl, methylphenyl, dimethylphenyl, trimethylphenyl, pyridyl, aminophenyl, sodium sulfonate group, 4-cumylphenoxy, sulfonic acid group, phenylthio, tert-butyl, hydroxyl, carbonyl, methoxy, amino, sulfonyl, or aldehyde group. Among these, the following are preferred: methyl, ethyl, propyl, butyl, halogen atom, sulfonic acid group, hydroxyl, carbonyl, methoxy, amino, sulfonyl, and aldehyde group.

[0052] In formulas (P-3), (P-4), and (P-5), X represents an inorganic atom that includes a metal atom. Specific examples include Ga, GaOH, GaCl, TiO, Ti, Si, V, Pb, SiCl2, Cu, Zn, Pd, Pb, Ni, Pt, Co, MnCl, FeCl, VO, and RuCO. Among these, Ga, GaOH, GaCl, TiO, Ti, SiCl2, Cu, Zn, Pd, Pb, Ni, Pt, Co, MnCl, FeCl, VO, and RuCO are preferred, while Ga, GaOH, GaCl, and TiO are more preferred.

[0053] In the above mechanism, when the constituent elements used to form the present invention exert a synergistic effect, the effects of the present invention can be achieved.

[0054] The present invention will be described in detail below by way of preferred embodiments. The present invention is not limited to the following embodiments, and appropriate changes and modifications to the following embodiments based on ordinary knowledge of those skilled in the art, without departing from the spirit of the invention, are also included within the scope of the present invention.

[0055] As used herein, the term "layer" refers not only to a layer with clearly defined boundaries or a layer with a flat, thin film shape, but also to a layer with a concentration gradient in which the concentration of elements varies gradually, or a layer that can form a complex, interwoven structure with other layers. Furthermore, elemental analysis of layers can be performed, for example, by determining and observing the elemental distribution of specific elements through TOF-SIMS / FE-TEM / EDS line analysis of cross-sections of photoelectric conversion elements.

[0056] Furthermore, the chemical structure of functional groups, etc., can be confirmed by nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR).

[0057] Figure 1 This is a schematic cross-sectional view illustrating the configuration of a photoelectric conversion element according to one embodiment of the present invention. Figure 1 The photoelectric conversion element includes a substrate 2 and a second electrode 3, an electron transport layer 4, a photoelectric conversion layer 5, a charge transport layer 6, and a first electrode 7 disposed thereon. One of the first electrode 7 and the second electrode 3 is a positive electrode, and the other is a negative electrode. Current can be extracted by connecting the first electrode 7 and the second electrode 3 to an external circuit.

[0058] The photoelectric conversion layer 5 is excited by light passing through the substrate 2, the second electrode 3, and the electron transport layer 4, or the first electrode 7 and the charge transport layer 6, to generate electrons or holes. That is, the photoelectric conversion layer 5 generates a current between the first electrode 7 and the second electrode 3. The electron transport layer 4 is disposed between the photoelectric conversion layer 5 and the two electrodes 3 and 7, and in some cases, it may not be formed. A configuration in which multiple electron transport layers 4 and photoelectric conversion layers 5 are stacked can be adopted. This configuration can also be called a "tandem structure". Furthermore, the photoelectric conversion element can be fabricated on the substrate 2 in the order of the first electrode 7, the charge transport layer 6, the photoelectric conversion layer 5, the electron transport layer 4, and the second electrode 3.

[0059] The components used to form the photoelectric conversion element of the present invention are described below.

[0060] Photoelectric conversion element

[0061] The photoelectric conversion element of the present invention comprises: a first electrode; a second electrode; and a photoelectric conversion layer disposed between the first electrode and the second electrode, the photoelectric conversion layer containing a crystal having a perovskite structure. The photoelectric conversion element is characterized by including a charge transport layer between the photoelectric conversion layer and the first electrode. Furthermore, to improve photoelectric conversion efficiency, a series configuration in which the photoelectric conversion elements are stacked can also be used. There are no limitations on the type of photoelectric conversion element to be stacked; for example, in addition to using a perovskite solar cell with a perovskite structure crystal in the photoelectric conversion layer, a silicon solar cell or a CIGS solar cell can also be used.

[0062] Methods for forming the layers, including the photoelectric conversion layer and the charge transport layer of the photoelectric conversion element of the present invention, include, for example, coating methods and vapor deposition methods. Examples of coating methods include dip coating, spin coating, spray coating, inkjet coating, meniscus coating, screen coating, roller coating, die coating, doctor blade coating, curtain coating, and wire rod coating. A coating method includes preparing a coating liquid for each layer described below, applying the liquid in the desired layer sequence, and drying the liquid. As such film-forming methods, the desired method is selected according to each layer.

[0063] The layers are described below.

[0064] [Substrate]

[0065] The photoelectric conversion element 1 of the present invention may include a substrate 2, examples of which include a transparent glass substrate, a ceramic substrate, and a transparent plastic substrate made of soda-lime glass or alkali-free glass. When light is taken in from the side of the first electrode 7, an opaque material may be used as the substrate 2, and when light is taken in from the side of the second electrode 3, the substrate 2 is formed of a transparent material.

[0066] [electrode]

[0067] There are no particular limitations on the materials used for the first electrode 7 or the second electrode 3; materials known to date can be used. Examples include: metals such as gold, silver, titanium, and copper; sodium; sodium-potassium alloys; lithium; magnesium; carbon; carbon nanotubes; aluminum; magnesium-silver mixtures; magnesium-indium mixtures; aluminum-lithium alloys; Al / Al2O3 mixtures; and Al / LiF mixtures. Examples of transparent electrode materials include: conductive transparent materials such as CuI, indium tin oxide (ITO), SnO2, zinc aluminum oxide (AZO), indium zinc oxide (IZO), zinc gallium oxide (GZO), fluorine-doped tin oxide (FTO), and antimony-doped tin oxide (ATO); and conductive transparent polymers. These materials can be used alone or in combination. At least one of the electrodes in the first electrode 7 or the second electrode 3 on the light incident side is a transparent electrode, and the other can be a transparent electrode or act as a reflective layer formed of a light-reflective material, or it can be a transparent electrode including a reflective layer on the side opposite to the light incident side. When the first electrode 7 is on the light incident side, the second electrode 3 and the substrate 2 can be a transparent electrode and a reflective layer, respectively. Transparent electrodes can be patterned electrodes.

[0068] [Photoelectric conversion layer]

[0069] The photoelectric conversion layer 5 comprises a crystal with a perovskite structure. The crystal with a perovskite structure used in this invention is preferably represented by the following general formula [1].

[0070] A o B p X q [1]

[0071] In the general formula [1], A represents a cation, B represents a cation, and X represents an anion.

[0072] "o", "p", and "q" satisfy 0 ≤ o ≤ 10, 0 ≤ p ≤ 10, and 0 ≤ q ≤ 20, respectively. A, B, and X can each be composed of a single material or a combination of two or more materials. Additives can be added within the range where the general formula holds. The general formula typically forms a perovskite crystal with a 3D structure, but when the cation A to be formed is large enough to fit within a crystal with a 3D perovskite structure, it can also form a crystal with a 2D perovskite structure, a crystal with a 2.5D perovskite structure possessing properties of both 2D and 3D perovskite structures, a two-layer crystal with 3D and 2D perovskite structures, or a crystal with a mixed 3D / 2D perovskite structure, each of which functions as a photoelectric conversion layer.

[0073] Two-layered crystals with 3D and 2D perovskite structures refer to crystals with 3D and 2D perovskite structures stacked as independent and separate layers. Crystals with mixed 3D / 2D perovskite structures refer to crystals with the following structures: regions or domains of crystals with 2D or 2.5D layered and 3D perovskite structures are mixed. Crystals with 2D or 2.5D perovskite structures can form Ruddlesden-Popper (RP), Dion-Jacobson (DJ), or alternating cations in the interlayer (ACI) perovskite structures.

[0074] As A in general formula [1], there are no particular restrictions on cation A. Cation A may have substituents or may not have substituents, and specific examples include the following structural formulas.

[0075] [Chemical Formula 6]

[0076]

[0077] [Chemical Formula 7]

[0078]

[0079] Furthermore, there are no particular restrictions on inorganic atoms, with lithium, cesium, sodium, potassium, and rubidium being preferred. These organic molecules or inorganic atoms can be used alone or in combination.

[0080] In general formula [1], B represents a cation atom, examples of which include lead, tin, bismuth, zinc, titanium, antimony, nickel, iron, cobalt, silver, copper, gallium, germanium, magnesium, calcium, indium, aluminum, manganese, chromium, molybdenum, and europium. Among these, lead, tin, bismuth, and silver are preferred from the viewpoint of the stability of the perovskite crystal structure. These atoms can be used alone or in combination.

[0081] In the general formula [1], X represents a halogen or chalcogen atom, examples of which include chlorine, bromine, iodine, oxygen, sulfur, selenium, tellurium, and polonium. These halogen or chalcogen atoms can be used alone or in combination. Halogen atoms are preferred because when halogens are included in the structure, the crystals with the perovskite structure become readily soluble in organic solvents, thereby enabling their application in inexpensive printing methods, etc. Iodine is even more preferred because the energy band gap of crystals with the perovskite structure is narrowed.

[0082] Specifically, MAPbI3, MAPbI3, FAPbCl3, FAPbI3, and MAPbI are 3D perovskites, 2D perovskites, and mixed 3D / 2D perovskites.x Br 3-x 、MAPbI x Cl 3-x 、Cs 0.05 (MA 0.17 FA 0.83 ) 0.95 Pb(I 0.83 Br 0.17 )3、{Cs x1 (FA x2 MA 1-x2 ) 1-x1} x3 Pb(I x4 Br 1-x4 ) x5 、Cs 0.05 FA 0.88 MA 0.07 PbI 2.56 Br 0.44 、(FAPbI3) 0.95 (MAPbBr3) 0.05 、(FAPbI3) 0.85 (MAPbBr3) 0.15 、CsPbI3、CsPbBr3、Cs x (MA) 1-x PbI3、Cs x (FA) 1-x PbI3、MA x (FA) 1-x PbI3、MA 0.17 FA 0.83 Pb(I 0.83 Br 0.17 )3、Cs 0.15 FA 0.85 PbI 2.55 Br 0.45 、Cs 0.05 FA 0.88 MA 0.07 PbI 2.56 Br 0.44 、Cs 0.15 FA 0.85 PbI 2.55 Br 0.45 、(AND)2(MA)2Pb3I 10 、(PTA)2(MA)4Pb5I 16 、(AND)2(MA)4Pb5I 16 、(ThMA)2(MA)2Pb3I 10 、(3BBA)2(MA)2Pb3I 10 、(ThMA)2(FA)4Pb5I16 (pF-PEA)2(FA) 0.3 MA 0.7 )4Pb5I 16 (PDMA)FA2Pb3I 10 (3AMPY)(MA)3Pb4I 13 (PDMA)A5Pb6I 19 (PDMA)MA3Pb4I 13 、(BA 0.9 PEA 0.1 )2MA4Pb5I 16 、(BA 0.9 PEA 0.1 )2MA3Pb4I 13 (BA)2MA2Pb3I 10 (BA)2MA3Pb4I 13 (BA)2MA4Pb5I 16 (BA)2MA3Pb4I 13 CsSnBr3, CsSnI3, FA 0.75 MA 0.25 Sn 0.95 Ge 0.05 I3, FAMASnGeI3, FAMnBr3, FAMnI3, MA2Sn3I8, MASnBr3, MASnGeI3 and MASnI3 are preferred.

[0083] The number of A, B, or X positions in each general formula can be adjusted to be too few or too many depending on the purpose, and the combination of x1 to x5 can be varied according to the purpose. Examples of combinations of x1 to x5 are shown in Table 1. Particularly preferred ranges for combinations of x1 to x5 are 0.03 ≤ x1 ≤ 0.10, 0.80 ≤ x2 ≤ 0.96, 0.95 ≤ x3 ≤ 1.05, 0.80 ≤ x4 ≤ 0.96, and 2.95 ≤ x5 ≤ 3.05. MACl can be included as a material for forming perovskite crystals.

[0084] [Table 1]

[0085] Table 1

[0086]

[0087] The aforementioned perovskite-structured crystals preferably have a cubic crystal structure in which metal atoms B, organic molecules A, and halogen atoms X are respectively positioned at the body center, vertices, and face centers. While the details are unclear, it is speculated that the orientation of the octahedrons within the crystal lattice can be easily altered when such a structure exists, thus increasing electron mobility in the perovskite-structured crystal and improving the photoelectric conversion efficiency of the photoelectric conversion element.

[0088] The perovskite-structured crystal used in this invention is preferably a crystalline semiconductor. The term "crystalline semiconductor" refers to a semiconductor capable of measuring the X-ray scattering intensity distribution to detect scattering peaks. When the perovskite-structured crystal is a crystalline semiconductor, the electron mobility in the perovskite-structured crystal increases, and the photoelectric conversion efficiency of the photoelectric conversion element is improved.

[0089] The thickness of the photoelectric conversion layer according to the present invention is preferably 5 nm or more and 2,000 nm or less. When the thickness is 5 nm or more, sufficient light absorption is possible, and when the thickness is 2,000 nm or less, the generated charge can be transported to each electrode. More preferably, the lower limit is 50 nm, more preferably, the upper limit is 1,200 nm, even more preferably, the lower limit is 100 nm, and even more preferably, the upper limit is 1,000 nm.

[0090] [charge transport layer]

[0091] In this invention, the charge transport layer preferably comprises a cyclic conjugated compound in which a plurality of pyrrole rings are linked by conjugated bonds, and at least one functional group selected from the group consisting of hydroxyl and carboxyl groups.

[0092] Furthermore, the molecular weight of the aliphatic resin having at least one functional group selected from the group consisting of hydroxyl and carboxyl groups is preferably 10,000 or more.

[0093] Aliphatic resins having at least one functional group selected from the group consisting of hydroxyl and carboxyl groups preferably further have at least one functional group selected from the group consisting of carbonyl, ester, ether, carboxyl, methoxy, amino, sulfonyl, aldehyde, amide, and thioether groups.

[0094] The mass of the cyclic conjugated compound in the charge transport layer is preferably 5 to 30 times that of the aliphatic resin in the charge transport layer, and more preferably 8 to 20 times that of the aliphatic resin in the charge transport layer.

[0095] The cyclic conjugated compound in the charge transport layer is preferably a phthalocyanine compound, which preferably has a central element. Furthermore, it is preferred that the phthalocyanine compound is a metallic phthalocyanine compound, more preferably a gallium phthalocyanine compound, and even more preferably a hydroxygallium phthalocyanine compound.

[0096] The thickness of the charge transport layer is preferably 1 nm or more and 1,000 nm or less, more preferably 5 nm or more and 500 nm or less, and particularly preferably 10 nm or more and 200 nm or less.

[0097] The charge transport layer can be formed by: preparing a coating liquid for the charge transport layer comprising the materials and solvents described above, forming a coating film of the liquid on the photoelectric conversion layer, and drying the coating film. Examples of solvents used for the coating liquid include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Among these solvents, alcohol-based solvents or aromatic hydrocarbon-based solvents are preferred.

[0098] [Second charge transport layer]

[0099] From the viewpoint of compatibility of the charge transport layer 6, the photoelectric conversion element 1 of the present invention may further include a second charge transport layer between the charge transport layer 6 and the first electrode 7.

[0100] There are no particular limitations on the materials used for the second charge transport layer, and examples include spirofluorene compounds, triphenylamine compounds, phenylene compounds, pyrene compounds, phthalocyanine compounds, carbazole compounds, fluorene compounds, phenylcyclohexane compounds, benzidine compounds, phenoxazine compounds, phenylenediamine compounds, thiocyanate compounds, and thiophene compounds. In particular, from the viewpoint of membrane interface compatibility, the second charge transport layer preferably has an aromatic ring, preferably contains a spirofluorene compound or a triphenylamine compound, and preferably contains spiro-OMeTAD (Spiro-OMeTAD) or PTAA.

[0101] Furthermore, to improve charge transport capability, the second charge transport layer may contain dopants as additives. Examples of substances that can be used as dopants include lithium compounds such as lithium bis(trifluoromethanesulfonyl)imide, cobalt compounds such as [tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(III)tris(bis(trifluoromethanesulfonyl)imide)], boron compounds such as tetra(pentafluorophenyl)borate, and molybdenum compounds such as tris[1-(methoxycarbonyl)-2-(trifluoromethyl)-ethane-1,2-dithioolene]molybdenum(tris[1-(methoxycarbonyl)-2-(triflu Molybdenum compounds such as (oromethyl)-ethane-1,2-dithiolene]molybdenum, organic compounds with a tetracyanoquinone dimethyl skeleton such as 2,3,4,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane, and organic compounds with a pyridine skeleton such as 4-tert-butylpyridine.

[0102] [Electron transport layer]

[0103] In the photoelectric conversion element of the present invention, such as Figure 1 and Figure 2As shown, an electron transport layer 4 can be disposed between the second electrode 3 and the photoelectric conversion layer 5.

[0104] There are no particular limitations on the materials used for electron transport layer 4, and examples include N-type conductive polymers, N-type low molecular weight organic semiconductors, N-type metal oxides, N-type metal sulfides, alkali metal halides, alkali metals, and surfactants. Specific examples include cyano-containing polyphenylene vinylidene, boron-containing polymers, bathocuproine, bathophenanthroline, aluminum hydroxyquinoline, oxadiazole compounds, benzimidazole compounds, naphthalenetetracarboxylic acid compounds, fullerene compounds, perylene compounds, phosphine oxide compounds, phosphine sulfide compounds, fluorine-containing phthalocyanines, titanium dioxide, zinc oxide, indium oxide, tin oxide, gallium oxide, tin sulfide, indium sulfide, and zinc sulfide.

[0105] The preferred lower limit for the thickness of the electron transport layer 4 is 1 nm, and the preferred upper limit is 2,000 nm. When the thickness is above 1 nm, holes can be sufficiently blocked, and when the thickness is below 2,000 nm, the electron transport layer 4 is unlikely to act as a resistor during electron transport, thus improving the photoelectric conversion efficiency. A more preferred lower limit for the thickness is 3 nm, a more preferred upper limit is 1,000 nm, a still more preferred lower limit is 5 nm, and a still more preferred upper limit is 500 nm.

[0106] Photoelectric conversion device

[0107] The photoelectric conversion device of the present invention includes the photoelectric conversion element of the present invention. The photoelectric conversion device can be formed by using multiple photoelectric conversion elements of the present invention. When multiple photoelectric conversion elements are connected, such a photoelectric conversion device can also be called a "photoelectric conversion battery" or a "photoelectric conversion module". In the photoelectric conversion element, elements with different absorption wavelengths can be stacked to increase the output voltage. Furthermore, the photoelectric conversion device includes the photoelectric conversion element of the present invention and an inverter. The inverter can be a converter that converts DC voltage to AC voltage. The photoelectric conversion device may include a power storage unit connected to the photoelectric conversion element. There are no limitations on the power storage unit, as long as it is capable of storing power. Examples include secondary batteries using lithium ions, all-solid-state batteries, and double-layer capacitors. To impart functions such as maintaining or increasing the amount of incident light, a surface layer that is difficult for water or dirt to adhere to can be added, or light-concentrating or light-guiding functions can be added.

[0108] [Moving Object]

[0109] Figure 3This is a perspective view schematically illustrating one embodiment of a mobile body including the photoelectric conversion element of the present invention. The mobile body 30 includes the photoelectric conversion element 31 of the present invention and a body 32 housing the photoelectric conversion element 31. The photoelectric conversion element 31 is disposed at a position on the body 32 capable of receiving ambient light. When the mobile body 30 is a vehicle, the photoelectric conversion element 31 may also be disposed on the roof. The electrical energy obtained through the photoelectric conversion element 31 can serve as the power source for the mobile body 30 or any other electrical equipment. The electrical energy generated by the power source of the mobile body 30 can be used to power the photoelectric conversion element 31. When the mobile body 30 is a vehicle, the frictional energy generated by braking can be converted into electrical energy for the control of the photoelectric conversion element 31.

[0110] The mobile body 30 can be, for example, a car, motorcycle, railway vehicle, ship, or flying body including artificial satellites, airplanes, and drones. There are no particular restrictions on the composition of the body 32 of the mobile body 30, but it is preferably made of a material with high strength.

[0111] [Building Materials]

[0112] Figure 4 This is a perspective view schematically illustrating one embodiment of a building material including the photoelectric conversion element of the present invention. The building material 40 may be the roof of a building. The building material 40 of this embodiment includes the photoelectric conversion element 41 of the present invention, a protective member 42 for protecting the photoelectric conversion element 41, a heat dissipation member 43, and exterior components 44a and 44b.

[0113] The building material 40 of the present invention may include a heat dissipation member 43 with a thermal conductivity higher than that of the photoelectric conversion element 41. Typically, when a building material containing a photoelectric conversion element is used for roofs or the like, sunlight can cause the temperature of the photoelectric conversion element 41 to rise, thereby reducing the photoelectric conversion efficiency. In this case, by using the heat dissipation member 43, the reduction in photoelectric conversion efficiency can be suppressed. Examples of heat dissipation members 43 include metals, alloys, liquid metals, and liquid resins.

[0114] Furthermore, the building material 40 of the present invention may include exterior panels 44a and 44b. Exterior panels 44a and 44b may be different colors or the same color. Exterior panels 44a and 44b may be composed of the same components or different components. Paint or a transparent substrate may be used as exterior panel components. Preferably, exterior panels with low light absorption and high heat shielding properties are used.

[0115] In addition to the above-mentioned application examples, the following application examples of the photoelectric conversion element of the present invention can be given: portable devices, such as calculators, sensors and small solar panels; wearable devices, such as glasses-type terminals, wristwatch-type terminals and portable medical devices; sheet-like structures supported by multiple frames, such as tents, plastic greenhouses and truck loading platforms; and structures used in a fixed manner, such as road panels, floating panels, flexible building materials utilizing substrates, wall-type building materials, glass-type building materials and large solar panels.

[0116] [Manufacturing Method of Photoelectric Conversion Components]

[0117] The method for manufacturing the photoelectric conversion element of the present invention includes the following steps: forming a first electrode; forming a second electrode; forming a photoelectric conversion layer comprising a crystal having a perovskite structure between the first electrode and the second electrode; and forming a charge transport layer between the photoelectric conversion layer and the first electrode.

[0118] The manufacturing process is described below, detailing each step.

[0119] [Steps for forming the first electrode and steps for forming the second electrode]

[0120] In the steps of forming the first electrode and forming the second electrode, appropriate methods can be selected according to the materials of the first electrode and the second electrode, respectively. Examples of such methods include, but are not limited to, sputtering, vacuum evaporation, chemical vapor deposition (CVD), and spray pyrolysis deposition (SPD). The materials of the first electrode and the second electrode are as described above. When one or both of the first electrode and the second electrode are transparent electrodes, the thickness of the transparent electrode is preferably 0.03 μm or more and 3 μm or less.

[0121] When manufacturing solar cells, machining processes for circuit formation can be performed between steps. Examples of machining processes include mechanical patterning and laser patterning.

[0122] [Modularization Steps]

[0123] The component extending up to the electrode can be sealed. Sealing methods include, for example, sealing with resin or sealing with a membrane. Examples of materials used for sealing include silazane, silicone rubber, resins each having a siloxane backbone, and glass.

[0124] Furthermore, from the viewpoint of suppressing adhesion between components during roll-to-roll winding, the surface of the sealed components can be hairlined.

[0125] [Steps for forming a photoelectric conversion layer]

[0126] The steps of forming the photoelectric conversion layer may include applying a liquid containing the material of the photoelectric conversion layer as described above. Examples of application methods include spin coating, blade coating, slot die coating, screen printing, rod coating, molding, printing transfer, dip-coating, inkjet printing, spraying, and vacuum evaporation. The method is appropriately selected from these methods depending on the properties of the photoelectric conversion layer to be manufactured (such as thickness control and orientation control). Annealing can be performed under reduced pressure or in an inactive atmosphere (in a nitrogen or argon atmosphere) to remove the solvent or dispersion medium from the applied liquid containing the photoelectric conversion layer. The annealing temperature is preferably 40°C or higher and 300°C or lower, more preferably 50°C or higher and 150°C or lower. Annealing is preferred because the materials used to form the layers interpenetrate at the interfaces between the stacked layers to increase the contact area, which in some cases increases the short-circuit current.

[0127] [Steps for forming a charge transport layer]

[0128] As a step in forming the charge transport layer, applying a liquid containing the charge transport layer material as described above is preferred. Examples of application methods include spin coating, blade coating, slot die coating, screen printing, bar coating, molding, printing transfer, dip-coating, inkjet printing, spraying, and vacuum evaporation.

[0129] Example

[0130] The invention is described in more detail below with reference to embodiments and comparative examples. The invention is not limited to the following embodiments without departing from its spirit. In the description of the following embodiments, unless otherwise stated, the term "part" is based on mass.

[0131] <Manufacturing steps of particle 1>

[0132] Step (1)

[0133] Under a nitrogen atmosphere, 5.46 parts of phthalonitrile and 45 parts of α-chloronaphthalene were added to a reactor. The mixture was then heated to 30°C and maintained at that temperature. Next, at this temperature (30°C), 3.75 parts of gallium trichloride were added to the mixture. The water concentration of the mixture at the time of addition was 150 ppm. The temperature of the mixture was then raised to 200°C. The mixture was then reacted at 200°C for 4.5 hours under a nitrogen atmosphere, followed by cooling. The product was filtered when the temperature reached 150°C. The resulting filtrate was washed with N,N-dimethylformamide at 140°C for 2 hours, followed by filtration. The resulting filtrate was washed with methanol and then dried to obtain gallium chlorophthalocyanine particles in 71% yield.

[0134] Step (2)

[0135] 4.65 parts of gallium chlorophthalocyanine particles were dissolved in 139.5 parts of concentrated sulfuric acid at 10°C. The solution was then added dropwise to 620 parts of ice water with stirring, causing the particles to recrystallize. The solution was then filtered under reduced pressure using a filter press. A No. 5C filter (manufactured by Advantec Toyo Kaisha, Ltd.) was used as the filter. The resulting wet filter cake (filtrate) was dispersed and washed with 2% ammonia for 30 minutes, and then filtered again using a filter press. Next, the resulting wet filter cake (filtrate) was dispersed and washed with deionized water, and then filtered three more times using a filter press. Finally, the filtrate was freeze-dried to obtain hydroxy gallium phthalocyanine particles (hydrated hydroxy gallium phthalocyanine particles) with a solid content of 23% by mass in 71% yield. The hydroxy gallium phthalocyanine particles were dried using a hyper-dry dryer (trade name: HD-06R, frequency (oscillation frequency): 2,455 MHz ± 15 MHz, manufactured by Biocon (Japan) Ltd.). Thus, hydroxy gallium phthalocyanine (OHGaPc) particles (crystals) with a water content of less than 1.0% by mass were obtained.

[0136] Step (3)

[0137] Five parts of hydroxygallium phthalocyanine particles were mixed with five parts of N-methylformamide solvent, and the mixture was dispersed for 6 hours in a sand mill (TSG-1 / 4G-4U, manufactured by Igarashi Machine Production Co., Ltd. (now AIMEX Co., Ltd.), with a disc diameter of 70 mm and five discs) containing five parts of glass beads. The mixture was then filtered and dried to obtain particle 1.

[0138] <Preparation of Resin Solution 1>

[0139] 1.0 g of polyvinyl butyral (trade name: BM-2, manufactured by Sekisui Chemical Co., Ltd., glass transition temperature: 71°C) was dissolved in 19 g of 2-propanol by stirring for 24 hours to obtain resin solution 1.

[0140] (Example 1)

[0141] [Formation of the electron transport layer]

[0142] A glass substrate containing ITO was washed, and tin(II) oxide with a concentration adjusted to 3% by mass was applied to it by spin coating. The resulting material was then heated at 150°C for 30 minutes to form an electron transport layer as a thin film with a thickness of 15 nm.

[0143] [Formation of the photoelectric conversion layer]

[0144] 22.4 mg of methylammonium bromide, 172 mg of formamidinium iodide, and 576 mg of lead iodide were dissolved in 600 μL of N,N-dimethylformamide and 160 μL of dimethyl sulfoxide, and the solution was stirred for 1 hour (Solution 1). Additionally, 389.72 mg of cesium iodide was dissolved in 1,000 μL of dimethyl sulfoxide, and the solution was stirred for 1 hour (Solution 2). Then, 40 μL of the cesium iodide solution (Solution 2) was added to Solution 1 to prepare a coating solution for the photoelectric conversion layer. The coating solution was applied to the electron transport layer by spin coating to form a Cs... 0.05 (FA 0.83 MA 0.17 ) 0.96 Pb(I 0.95 Br 0.05 A photoelectric conversion layer consisting of 3 and a thickness of 500 nm.

[0145] [Formation of the charge transport layer]

[0146] 0.1 g of particle 1 and 0.01 g of calixarene compound (Japanese Patent Application Laid-Open No. 2003-207913) were mixed with 10.6 g of 2-propanol, and 11 g of zirconium oxide beads were added to the mixture. The mixture was then dispersed in a paint stirrer (manufactured by ToyoSeiki Co., Ltd.) for 6 hours. Next, 0.2 g of resin solution 1 was added, and the mixture was again dispersed in a paint stirrer for 6 hours to prepare a coating solution for the charge transport layer. The coating solution for the charge transport layer was spin-coated onto the photoelectric conversion layer to form a charge transport layer with a thickness of 150 nm.

[0147] [Formation of the second charge transport layer]

[0148] 0.15 g of spiro-OMeTAD, used as a material for the second charge transport layer, was dissolved in 2.2 g of chlorobenzene. 36 μL of an acetonitrile solution obtained by dissolving 0.2 g of lithium bis(trifluoromethanesulfonyl)imide in 0.3 g of acetonitrile and 60 μL of 4-tert-butylpyridine (TBP) were added to the chlorobenzene solution, and the contents were mixed. Furthermore, 58 μL of an acetonitrile solution obtained by dissolving 0.11 g of [tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(III)tris(bis(trifluoromethanesulfonyl)imide)] in 0.3 g of acetonitrile was mixed to prepare a material solution for the second charge transport layer. The solution was applied to the charge transport layer by spin coating to form a second charge transport layer with a thickness of 200 nm.

[0149] [Formation of the first electrode]

[0150] A layer with a thickness of 80 nm and an area of ​​0.09 cm² was formed on the second charge transport layer using vacuum evaporation. 2 Gold electrodes are used to obtain a photoelectric conversion element.

[0151] [Analysis of compound amount]

[0152] The electrode surfaces of the photoelectric conversion element are peeled off to expose the surface of the charge transport layer. The surface of the charge transport layer is then wiped with a solvent (such as a cotton swab), dissolved in deuterated sulfuric acid, and subjected to further processing. 1 H-NMR determination (equipment: BRUKER AVANCE 3-500). In addition, the stripped charge transport layer components were subjected to mass and structural analysis by elemental analysis (such as GPC and MALDI-TOF-MS, IR, gas chromatography, XPS, and EDX) to confirm the presence of the compounds.

[0153] Furthermore, after cutting the photoelectric conversion element and fixing the sample on an inclined sample stage, the thickness of the charge transport layer was observed using a cross-sectional SEM (equipment: SmartSEM, manufactured by Carl Zeiss Co., Ltd.). Regarding the crystallinity of each material, diffraction peaks were observed by XRD (equipment: RINT-TTRII X-ray diffractometer, manufactured by Rigaku Corporation).

[0154] (Example 2)

[0155] The photoelectric conversion element was obtained in the same manner as in Example 1, except that a polyvinyl butyral resin with a different hydroxyl ratio (trade name: BM-S, manufactured by Sekisui Chemical Co., Ltd., glass transition temperature: 67°C) was used as an aliphatic resin with hydroxyl groups.

[0156] (Example 3)

[0157] Between the charge transport layer and the photoelectric conversion layer, a thin film solution was prepared by dissolving 2.49 mg of 2-phenylethylamine hydroiodate in 1 mL of 2-propanol, and this thin film solution was then spin-coated onto the photoelectric conversion layer to form a thin film layer with a thickness of 20 nm. Except as described above, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0158] (Example 4)

[0159] The cyclic conjugated compound in which multiple pyrrole rings are linked by conjugation bonds is changed to gallium chlorophthalocyanine (ClGaPc). Except as described above, the photoelectric conversion element is obtained in the same manner as in Example 1.

[0160] (Example 5)

[0161] The cyclic conjugated compound in which multiple pyrrole rings are linked by conjugation bonds is changed to copper phthalocyanine (CuPc). Except as described above, the photoelectric conversion element is obtained in the same manner as in Example 1.

[0162] (Example 6)

[0163] The cyclic conjugated compound in which multiple pyrrole rings are linked by conjugation bonds is changed to titanium phthalocyanine (TiOPc). Except as described above, the photoelectric conversion element is obtained in the same manner as in Example 1.

[0164] (Example 7)

[0165] The cyclic conjugated compound in which multiple pyrrole rings are linked by conjugation bonds is changed to zinc phthalocyanine (ZnPc). Except as described above, the photoelectric conversion element is obtained in the same manner as in Example 1.

[0166] (Example 8)

[0167] The cyclic conjugated compound in which multiple pyrrole rings are linked by conjugation bonds is changed to dichlorosilylphthalocyanine (SiPcCl2). Except as described above, the photoelectric conversion element is obtained in the same manner as in Example 1.

[0168] (Example 9)

[0169] The cyclic conjugated compound in which multiple pyrrole rings are linked by conjugation bonds is transformed into a ligandless phthalocyanine (Pc). Except as described above, the photoelectric conversion element is obtained in the same manner as in Example 1.

[0170] (Example 10)

[0171] The cyclic conjugated compound in which multiple pyrrole rings are linked by conjugation bonds is changed to tetraphenylporphyrin (TPP). Except as described above, the photoelectric conversion element is obtained in the same manner as in Example 1.

[0172] (Example 11)

[0173] Except for using 0.2g of particles 1 in the preparation of the coating liquid 1 for the charge transport layer, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0174] (Example 12)

[0175] Except for using 0.08 g of particles 1 in the preparation of the coating liquid 1 for the charge transport layer, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0176] (Example 13)

[0177] Except for using 0.3g of particles 1 in the preparation of the coating liquid 1 for the charge transport layer, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0178] (Example 14)

[0179] Except for using 0.05 g of particles 1 in the preparation of the coating liquid 1 for the charge transport layer, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0180] (Example 15)

[0181] Except for using 0.35g of particles 1 in the preparation of the coating liquid 1 for the charge transport layer, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0182] (Example 16)

[0183] Except for using 0.02g of particles 1 in the preparation of the coating liquid 1 for the charge transport layer, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0184] (Example 17)

[0185] In the preparation of resin solution 1, the aliphatic resin with hydroxyl groups was changed to KS-10 (manufactured by Sekisui Chemical Co., Ltd., glass transition temperature: 105°C). Except as described above, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0186] (Example 18)

[0187] In the preparation of resin solution 1, the resin was changed to PBMA (a compound represented by formula (E-1)) as an aliphatic resin having a carboxyl group. Except as described above, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0188] [Chemical Formula 8]

[0189]

[0190] (Example 19)

[0191] In the preparation of resin solution 1, the resin was changed to PHM (a compound represented by formula (E-2)) as an aliphatic resin having hydroxyl groups. Except as described above, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0192] [Chemical Formula 9]

[0193]

[0194] (Example 20)

[0195] In the preparation of resin solution 1, the resin was changed to PVA (a compound represented by formula (E-3)) as an aliphatic resin having hydroxyl groups. Except as described above, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0196] [Chemical Formula 10]

[0197]

[0198] (Example 21)

[0199] In the preparation of resin solution 1, the resin was changed to PMMMA (a compound represented by formula (E-4)) as an aliphatic resin having hydroxyl groups. Except as described above, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0200] [Chemical Formula 11]

[0201]

[0202] (Example 22)

[0203] The photoelectric conversion element is obtained in the same manner as in Example 1, except that a second charge transport layer is not used.

[0204] (Example 23)

[0205] In the preparation of resin solution 1, the aliphatic resin with hydroxyl groups was changed to BX-1 (manufactured by Sekisui Chemical Co., Ltd., glass transition temperature: 95°C). Except as described above, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0206] (Example 24)

[0207] In the preparation of resin solution 1, the resin was changed to polyacrylic acid (weight average molecular weight: 25,000, manufactured by FUJIFILM Wako Pure Chemical Corporation), an aliphatic resin with carboxyl groups, and 2-propanol was changed to ethanol. Except as described above, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0208] (Comparative Example 1)

[0209] Except that in the preparation of resin solution 1, an aliphatic resin having at least one group selected from the group consisting of hydroxyl and carboxyl groups is not used (i.e., resin solution 1 is not used), the photoelectric conversion element is obtained in the same manner as in Example 1.

[0210] (Comparative Example 2)

[0211] Except that in the preparation of the coating liquid for the charge transport layer, a cyclic conjugated compound in which multiple pyrrole rings are linked by conjugated bonds is not used, the photoelectric conversion element is obtained in the same manner as in Example 1.

[0212] (Comparative Example 3)

[0213] Except that in the preparation of the coating liquid for the charge transport layer, instead of using a cyclic conjugated compound in which multiple pyrrole rings are linked by conjugated bonds, a spiro-OMeTAD is used, the photoelectric conversion element is obtained in the same manner as in Example 1.

[0214] (Comparative Example 4)

[0215] Except that in the preparation of resin solution 1, instead of using an aliphatic resin having at least one group selected from the group consisting of hydroxyl and carboxyl groups, poly(3-hexylthiophene-2,5-diyl) P3HT (manufactured by Sigma-Aldrich CO. LLC, glass transition temperature: 9.3°C), the photoelectric conversion element was obtained in the same manner as in Example 1.

[0216] (Comparative Example 5)

[0217] In the preparation of resin solution 1, an aliphatic resin having at least one group selected from the group consisting of hydroxyl and carboxyl groups was replaced with KUREHA KF polymer (manufactured by Kuraray Co., Ltd., glass transition temperature: -35°C). Except as described above, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0218] (Comparative Example 6)

[0219] Except that in the preparation of resin solution 1, the aliphatic resin having at least one group selected from the group consisting of hydroxyl and carboxyl groups is changed to PSTFSI (a compound represented by the following formula (E-5)), and the cyclic conjugated compound in which multiple pyrrole rings are linked by conjugated bonds is changed to copper phthalocyanine (CuPc), the photoelectric conversion element is obtained in the same manner as in Example 1.

[0220] [Chemical Formula 12]

[0221]

[0222] (Comparative Example 7)

[0223] Except that in the preparation of resin solution 1, the aliphatic resin having at least one group selected from the group consisting of hydroxyl and carboxyl groups was changed to PSTFSI, the photoelectric conversion element was obtained in the same manner as in Example 1.

[0224] The specific composition of the charge transport layer in the photoelectric conversion elements manufactured in Examples 1-24 and Comparative Examples 1-7, as well as the presence or absence of a second charge transport layer or thin film layer, are shown in Table 2.

[0225] [evaluate]

[0226] The following evaluation is performed on the photoelectric conversion elements obtained in each embodiment and comparative example.

[0227] (Power generation efficiency evaluation)

[0228] In Example 1, a power supply (manufactured by Keithley Instruments, Model 236) was connected between the electrodes of the photoelectric conversion element, and a solar simulator (manufactured by Yamashita Denso Corporation) was used at 100 mW / cm². 2 A constant light was irradiated with an intensity of [insert intensity here], and the resulting current and voltage were then measured. The photoelectric conversion efficiency was thus evaluated. The series resistance was approximated by the reciprocal of the slope of the resulting current-voltage curve near Voc, and the shunt resistance was approximated by the reciprocal of the slope of the resulting current-voltage curve near Jsc. The leakage resistance of the photoelectric conversion element was evaluated using the values ​​of the series resistance and the shunt resistance. Examples 2-24 and Comparative Examples 1-7 were each evaluated in the same manner as in Example 1 to determine their photoelectric conversion efficiency. The results are expressed as relative values ​​when the result of Example 1 is set to 1. The results are shown in Table 3.

[0229] [Table 2]

[0230]

[0231] [Table 3]

[0232]

[0233] This invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, the claims are appended to disclose the scope of the invention.

[0234] This application references Japanese patent applications filed on October 27, 2023: No. 2023-184761, No. 2023-184756, No. 2023-184750, No. 2023-216294, No. 2023-216296, No. 2023-216299, and No. 2024-022244, filed on February 16, 2024. Priority is claimed in the following patent applications: Japanese Patent Application No. 2024-022251, filed February 16, 2024, Japanese Patent Application No. 2024-022246, filed May 28, 2024, and Japanese Patent Application No. 2024-086015, filed October 23, 2024, the entire contents of which are incorporated herein by reference.

[0235] Explanation of reference numerals in the attached figures

[0236] 1. Photoelectric conversion element

[0237] 2 substrate

[0238] 3 Second electrode

[0239] 4. Electron transport layer

[0240] 5 Photoelectric conversion layer

[0241] 6. Charge transport layer

[0242] 7 First Electrode

Claims

1. A photoelectric conversion element, comprising: First electrode; Second electrode; as well as A photoelectric conversion layer is disposed between the first electrode and the second electrode, the photoelectric conversion layer comprising crystals having a perovskite structure. The photoelectric conversion element includes a charge transport layer between the photoelectric conversion layer and the first electrode, the charge transport layer comprising: Cyclic conjugated compounds in which multiple pyrrole rings are linked by conjugated bonds; and An aliphatic resin having at least one functional group selected from the group consisting of hydroxyl and carboxyl groups.

2. The photoelectric conversion element according to claim 1, wherein the photoelectric conversion element includes a second charge transport layer between the first electrode and the charge transport layer.

3. The photoelectric conversion element according to claim 2, wherein the second charge transport layer comprises a spirofluorene compound.

4. The photoelectric conversion element according to any one of claims 1 to 3, wherein the aliphatic resin further has at least one functional group selected from the group consisting of carbonyl, ester, ether, carboxyl, methoxy, amino, sulfonyl, aldehyde, amide and thioether.

5. The photoelectric conversion element according to any one of claims 1 to 4, wherein the cyclic conjugated compound in the charge transport layer contains 5 to 30 times the mass of the aliphatic resin in the charge transport layer.

6. The photoelectric conversion element according to any one of claims 1 to 5, wherein the cyclic conjugated compound in the charge transport layer contains 8 to 20 times the mass of the aliphatic resin in the charge transport layer.

7. The photoelectric conversion element according to any one of claims 1 to 6, wherein the cyclic conjugated compound is a phthalocyanine compound.

8. The photoelectric conversion element according to claim 7, wherein the phthalocyanine compound has a central element.

9. The photoelectric conversion element according to claim 7 or 8, wherein the phthalocyanine compound is a metal phthalocyanine compound.

10. The photoelectric conversion element according to claim 9, wherein the metal phthalocyanine compound is a gallium phthalocyanine compound.

11. The photoelectric conversion element according to claim 10, wherein the gallium phthalocyanine compound is a hydroxygallium phthalocyanine compound.

12. The photoelectric conversion element according to any one of claims 1 to 11, wherein the glass transition temperature of the aliphatic resin is below 95°C.

13. A photoelectric conversion device comprising the photoelectric conversion element according to any one of claims 1 to 12.

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