Method for manufacturing photoelectric conversion element

Abstract

To provide a method for manufacturing a photoelectric conversion element that improves photoelectric conversion efficiency.SOLUTION: Provided is a method for manufacturing a photoelectric conversion element having a first electrode, a photoelectric conversion layer including a crystal of a perovskite structure, a charge transport layer, and a second electrode. The method includes a step of applying a charge transport layer coating liquid onto a surface of the photoelectric conversion layer to form the charge transport layer. The charge transport layer coating liquid includes alcohol liquid, resin, and charge transporting particles.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a photoelectric conversion element. [Background technology]

[0002] In order to solve the problem of fossil energy depletion and the global environmental problems caused by the use of fossil energy, active research is being conducted on renewable and clean alternative energy sources such as solar energy, wind power, and hydroelectric power. Among them, interest in solar cells that directly convert sunlight into electrical energy is increasing. Here, a solar cell refers to a cell that generates a current and voltage by utilizing the photovoltaic effect in which light energy from sunlight is absorbed and electrons and holes are generated.

[0003] Currently, np diode type silicon (Si) single crystal-based solar cells with a light energy conversion efficiency of over 20% are widely known and are actually used for photovoltaic power generation. However, these require high-temperature processing and the materials themselves are expensive, so they have the problem of high cost per unit of power. In addition, there are problems with supply in terms of silicon resources.

[0004] On the other hand, solar cells using organic materials (hereinafter referred to as "organic solar cells") do not require high-temperature processing and can be produced using a sheet-like substrate by the so-called roll-to-roll method, which is expected to reduce costs. However, further improvements in power generation efficiency and durability are required for the practical use of organic solar cells. In particular, perovskite-type solar cells, which have crystals with a perovskite structure as a photoelectric conversion layer, have excellent photoelectric conversion characteristics, so development is being promoted for the practical use of solar cells.

[0005] For example, Patent Document 1 describes a technique for improving peeling from an electrode by including an organic semiconductor and a polymer compound having a glass transition temperature of 100° C. or higher in a hole transport layer. Patent Document 2 describes a technique for improving photoelectric conversion efficiency by forming a layer containing a phthalocyanine compound between a hole transport layer and a perovskite. Non-Patent Document 1 describes a technique for improving conversion efficiency by mixing copper phthalocyanine and a conductive polymer in a hole transport layer. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2018-170382 A [Patent Document 2] Patent Publication No. 2022-168820 [Non-patent literature]

[0007] [Non-Patent Document 1] Q. Hu,et al,Sol.RRL,2019,3,1800264 Summary of the Invention [Problem to be solved by the invention]

[0008] According to the studies of the present inventors, it has been found that the photoelectric conversion elements described in Patent Document 1, Patent Document 2, and Non-Patent Document 1 have room for improvement in photoelectric conversion efficiency. Therefore, an object of the present invention is to provide a method for producing a photoelectric conversion element with improved photoelectric conversion efficiency. [Means for solving the problem]

[0009] The above object can be achieved by the present invention. A method for producing a photoelectric conversion element having a first electrode, a photoelectric conversion layer including a crystal having a perovskite structure, a charge transport layer, and a second electrode, comprising the steps of: A step of applying a charge transport layer coating liquid onto a surface of the photoelectric conversion layer to form a charge transport layer, The method for producing a photoelectric conversion element is characterized in that the charge transport layer coating liquid contains an alcohol liquid, a resin, and charge transport particles. Effect of the Invention

[0010] According to the present invention, it is possible to provide a method for producing a photoelectric conversion element having improved photoelectric conversion efficiency. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic cross-sectional view in a thickness direction of a photoelectric conversion element manufactured by a method for manufacturing a photoelectric conversion element of the present invention. [Diagram 2] 1 is a perspective view showing a schematic diagram of an example of a moving body provided with a photoelectric conversion element manufactured by a method for manufacturing a photoelectric conversion element according to the present invention; [Diagram 3] FIG. 1 is a perspective view that illustrates an example of a building material provided with a photoelectric conversion element manufactured by the manufacturing method for a photoelectric conversion element of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] <One embodiment> One embodiment relates to a method for manufacturing a photoelectric conversion element. The method for producing a photoelectric conversion element of the present invention includes the steps of: A method for producing a photoelectric conversion element having a first electrode, a photoelectric conversion layer including a crystal having a perovskite structure, a charge transport layer, and a second electrode, comprising the steps of: A step of applying a charge transport layer coating liquid onto a surface of the photoelectric conversion layer to form a charge transport layer, The charge transport layer coating liquid is characterized by containing an alcohol liquid, a resin, and charge transporting particles.

[0013] As a result of investigation, the present inventors found that a photoelectric conversion element with excellent photoelectric conversion efficiency can be manufactured by the above manufacturing method. A coating solution in which charge transport particles are dispersed in a non-alcoholic solvent is applied onto the surface of a photoelectric conversion layer containing crystals of a perovskite structure to produce a photoelectric conversion element. When the cross section of the photoelectric conversion element was observed under an electron microscope, voids were found between the photoelectric conversion layer and the layer of charge transport particles, and there were also areas where the photoelectric conversion layer was not covered with the charge transport particles.

[0014] In contrast, in the case of a photoelectric conversion element formed by the manufacturing method of the present invention, it has been found that the voids and uncovered parts are reduced, and a layer containing charge transport particles that is denser and more closely attached to the photoelectric conversion layer can be formed. This is thought to have made the movement of charges from the photoelectric conversion layer to the electrode smoother, improving the photoelectric conversion efficiency. The present inventors speculate as follows about the reason why the charge transport particles form a layer with good coverage that is dense and closely attached to the photoelectric conversion layer in the present invention.

[0015] The charge transport layer coating liquid of the present invention is a liquid containing an alcohol liquid, a resin, and charge transport particles. The charge transport particles are in a state of being dispersed in the alcohol liquid. The charge transport layer is formed by coating the charge transport layer coating liquid on the surface of the photoelectric conversion layer, and the alcohol liquid evaporates to form a layer containing the charge transport particles and the resin.

[0016] In the applied charge transport layer coating liquid, as the alcohol liquid evaporates, the distance between the charge transport particles decreases. At this time, the resin is interposed between the charge transport particles, and the particle dispersion state is stabilized by the steric barrier of the resin, preventing excessive aggregation in the process of reducing the distance between the particles, and the alcohol liquid is stably deposited on the photoelectric conversion layer to form a layer with good coverage. In addition, since the alcohol liquid has both a hydrophilic part due to a hydroxyl group and a hydrophobic part made of a hydrocarbon in a balanced manner, it is stably interposed between the charge transport particles and contributes to preventing excessive aggregation of the particles during the formation of the coating film. Furthermore, since the perovskite structure crystal of the photoelectric conversion layer has a hydrogen bonding surface, it is compatible with the alcohol liquid due to hydrogen bonding interaction.

[0017] In the case of non-alcohol, the mixture does not mix well, so the non-alcohols tend to aggregate with each other, which results in particle aggregation and the occurrence of uncoated areas. The alcohol liquid is compatible with both the perovskite crystals and the charge transport particles, so it does not cause excessive particle aggregation during the coating film formation process as the alcohol liquid evaporates. As explained by the above mechanism, the synergistic effects of each component are such that the charge transport particles form a dense, tightly adhered layer with good coverage on the photoelectric conversion layer, improving the photoelectric conversion efficiency.

[0018] As explained above, the respective components exert a synergistic effect on each other, thereby making it possible to achieve the effects of the present invention.

[0019] The present invention will be described in detail below with reference to preferred embodiments. The present invention is not limited to the following embodiments, and any modifications or improvements to the following embodiments based on the ordinary knowledge of a person skilled in the art without departing from the spirit of the present invention are also included in the scope of the present invention.

[0020] In this specification, the term "layer" refers not only to a layer having a clear boundary or a flat thin-film layer, but also to a layer having a concentration gradient in which the contained elements change gradually, or to a layer that can form a complex structure together with other layers. Elemental analysis of the layer can be performed, for example, by performing TOF-SIMS / FE-TEM / EDS line analysis measurement of the cross section of the photoelectric conversion element to confirm the element distribution of a specific element. Analysis of each layer may be performed by peeling off the completed photoelectric conversion element to expose the layer to be analyzed. In addition, analysis of the compounds in the charge transport layer coating solution can be performed by mass and structure analysis using elemental analysis such as 1H-NMR, GPC, MALDI-TOF-MS, IR, gas chromatography, liquid chromatography, XPS, and EDX.

[0021] The method for producing a photoelectric conversion element of the present invention has a first electrode, a photoelectric conversion layer containing a crystal of a perovskite structure, a charge transport layer, and a second electrode. FIG. 1 is a cross-sectional view showing a schematic configuration of a photoelectric conversion element produced by the method for producing a photoelectric conversion element of the present invention. The photoelectric conversion element has a second electrode 3, an electron transport layer 4, a photoelectric conversion layer 5, a charge transport layer 6, and a first electrode 7 on a substrate 2. One of the first electrode 7 and the second electrode 3 is an anode and the other is a cathode, and a current can be extracted by connecting the first electrode 7 and the second electrode 3 with an external circuit.

[0022] The photoelectric conversion layer 5 is excited by light incident through the substrate 2, the second electrode 3, and the electron transport layer 4, or through the first electrode 7 and the charge transport layer 6, and generates 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 a layer disposed between the photoelectric conversion layer 5 and two electrodes (the second electrode 3 and the first electrode 7), and may not be formed in some cases. A configuration in which a plurality of electron transport layers 4 and photoelectric conversion layers 5 are stacked may be used. Such a configuration may be called a tandem structure.

[0023] The photoelectric conversion element of the present invention is characterized by having a first electrode 7, a second electrode 3, a photoelectric conversion layer 5 containing a crystal of a perovskite structure disposed between the first electrode 7 and the second electrode 3, and a charge transport layer 6 between the photoelectric conversion layer 5 and the first electrode 7. In order to improve the photoelectric conversion efficiency, the photoelectric conversion elements 1 may be stacked in a tandem type. The photoelectric conversion elements to be stacked are not limited to the type of photoelectric conversion element, and may be a silicon solar cell, a CIGS solar cell, or the like, in addition to a perovskite solar cell using a crystal of a perovskite structure for the photoelectric conversion layer 5.

[0024] Examples of methods for forming each layer including the photoelectric conversion layer and the charge transport layer of the photoelectric conversion element 1 include a coating method and a vapor deposition method. Examples of coating methods include dip coating, spin coating, spray coating, inkjet coating, meniscus coating, screen coating, roll coating, die coating, blade coating, curtain coating, and wire bar coating. The coating method is a method in which a coating liquid for each layer described later is prepared, coated in the desired layer order, and dried. A desired method can be selected from these film formation methods according to each layer. Each step will be described below.

[0025] [Step of forming charge transport layer] The method for producing a photoelectric conversion element of the present invention includes a step of applying a charge transport layer coating liquid onto the surface of a photoelectric conversion layer 5 to form a charge transport layer 6, and the charge transport layer coating liquid contains an alcohol liquid, a resin, and charge transport particles.

[0026] The thickness of the charge transport layer 6 is preferably 1 nm or more and 1000 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.

[0027] In the method for producing a photoelectric conversion element of the present invention, the charge transport layer coating liquid contains an alcohol liquid, a resin, and charge transport particles (as a charge transport material). In the charge transport layer coating liquid of the present invention, the charge transport material (charge transport particles) is dispersed in the coating liquid and exists in a particulate form. By forming the charge transport layer in a particulate form, the charge transport layer can maintain high crystallinity and exhibit its inherent high charge transport ability.

[0028] The particle shape of the charge transport particles is preferably a particle with a small aspect ratio, such as an approximately spherical shape, a rugby ball shape, a cylindrical shape, a flat shape, etc. For example, when the particle has a large aspect ratio, such as a needle shape, the particles must be deposited in the same direction in order to improve the coverage.

[0029] In other words, even if the particles can be deposited on the photoelectric conversion layer without excessive aggregation while remaining in a stable dispersion state, the shape of the particles tends to leave some parts of the photoelectric conversion layer that are not covered with the charge transport particles.In addition, the particles tend to pile up on other particles, so that voids tend to remain between the photoelectric conversion layer and the layer of charge transport particles, which reduces the effect of the present invention.

[0030] The aspect ratio of the charge transporting particles is preferably 5 or less, more preferably 3 or less. Examples of particle shapes that reduce the effect of the present invention include needles and fibers. The aspect ratio is greater than 10.

[0031] Specific examples of the charge transporting particles include phthalocyanine pigments, azo pigments, lake pigments, quinacridone pigments, dioxazine pigments, perylene pigments, and isoindolinone pigments.

[0032] In the method for producing a photoelectric conversion element of the present invention, the charge transporting particles are preferably particles containing a cyclic conjugated compound formed by conjugating a plurality of pyrrole rings. The cyclic conjugated compound formed by conjugating a plurality of pyrrole rings has a planar structure, and the particles are composed of an aggregate of crystallites in which the planar structures overlap. The crystallites have a highly polar surface containing a π-electron cloud and a nitrogen atom on the surface in the vertical direction of the planar structure, and a non-polar surface on the surface in the horizontal direction of the planar structure.

[0033] Therefore, the particles in which the crystallites are gathered have a polar surface and a non-polar surface. Since the alcohol has both a hydrophilic portion and a hydrophobic portion, the particles containing the cyclic conjugated compound in which a plurality of pyrrole rings are conjugated with the alcohol are suitably dispersed, and the coverage of the charge transport layer on the photoelectric conversion layer is improved. In addition, the particles containing the cyclic conjugated compound in which a plurality of pyrrole rings are conjugated with the alcohol are preferable because they show high charge transport ability.

[0034] In the method for producing a photoelectric conversion element of the present invention, the charge transporting particles are more preferably particles containing a phthalocyanine compound, and further, the charge transporting particles are more preferably particles having a structure represented by the following formula (Pc-2). By doing so, the charge transporting particles are likely to interact with alcohol or resin, and the coating property is likely to be improved. In addition, it is more preferable because it has good crystallinity and high charge transportability. [ka]

[0035] In the above formula (Pc-2), M represents H2, a metal atom having a ligand, or a metal atom having no ligand. In the present invention, the structure of a chemical substance can be determined by nuclear magnetic resonance (NMR) spectroscopy. In particular, when M in the above formula (Pc-2) is H2, the above formula (Pc-2) is represented by the following formula (Pc-1). [ka]

[0036] Specific examples of the resin include polyacetal resin, acrylic resin, polyarylate resin, polycarbonate resin, polyvinyl acetate resin, polyester resin, polyamide resin, polyurethane resin, and polystyrene resin.

[0037] In the method for producing a photoelectric conversion element of the present invention, the resin is preferably a resin having a Lewis basic functional group. The Lewis basic functional group acts electronically on the charge transport particles, thereby enhancing the interaction between the particles and the resin, making it easier for the resin to be interposed between the particles, and making it easier to obtain the effect of steric barrier stabilization by the resin. If the particles are cyclic conjugated compounds formed by conjugating multiple pyrrole rings, they are more effective because they are more likely to electronically interact with the Lewis basic functional group.

[0038] Specific examples of Lewis basic functional groups include hydroxyl, halogen, sulfo, amino, carbonyl, ester, ether, carboxyl, aldehyde, methoxy, amide, sulfide, cyano, thienyl, thienylidene, pyridyl, furyl, pyrazolyl, imidazolyl, oxazolyl, and thiazolyl groups. Among these, hydroxyl, carbonyl, ether, ester, pyridyl, and thienylidene groups are preferred from the viewpoint of electronic interaction.

[0039] In the method for producing a photoelectric conversion element of the present invention, the resin preferably has at least one functional group selected from the group consisting of a hydroxyl group, a carbonyl group, an ether group, an ester group, a pyridyl group, and a thienylidene group. In the present invention, the functional group of the resin can be confirmed, for example, by nuclear magnetic resonance (NMR). The thienylidene group has a structure represented by the following formula (A). [ka]

[0040] In particular, it is more preferable that the resin has at least two of these functional groups in terms of ease of interaction. Different functional groups may be contained in one resin, or two resins having different functional groups may be mixed. It is preferable that the Lewis basic functional group is contained in the repeating structure of the resin.

[0041] Specific examples of the resin having a Lewis basic functional group that can be preferably used in the present invention are given below. Polyvinyl butyral, poly(4-vinylpyridine), poly(vinyl chloride), poly(vinylidene fluoride), polyacrylonitrile, poly(vinylidene fluoride-co-hexafluoropropylene), poly(acrylonitrile-co-butadiene), poly(styrene-co-acrylonitrile), polychloroprene, poly(4-chlorostyrene), polymethyl methacrylate, polyvinyl acetate, polyethyleneimine, polyvinyl alcohol, polyacrylic acid, poly(sodium 4-styrenesulfonate), poly(allylamine hydrochloride), sodium polyacrylate, poly(allylamine hydrochloride), poly(4-styrenesulfonic acid), poly(N-isopropylacrylamide), poly(2-ethyl-2-oxazoline), poly(ethylene-alt-maleic anhydride), poly(2-acrylamido-2-methyl-1-propanesulfonic acid), poly(vinyl sulfate) potassium salt, polyanethol sulfonic acid sodium salt, poly(2-dimethylamino)ethyl methacrylate) methyl chloride quaternary salt, poly(methyl vinyl ether), poly(2-propyl acrylic acid), polyvinylpyrrolidone, polypropylene glycol, poly(propylene carbonate), polyvinyl acetate, poly(tetrahydrofuran), nylon-6, poly(ethylene-co-vinyl acetate), poly(propylene glycol) bis(2-aminopropyl ether), poly(bisphenol A carbonate), poly(1,4-butylene adipate), poly(4-vinylphenol), poly(propylene glycol) monobutyl ether, poly Preferred are poly(glycidyl methacrylate), polybutyl acrylate, poly(ethylene succinate), poly(propylene glycol) methacrylate, nylon 11, nylon 12, poly(2-ethylhexyl acrylate), poly(bisphenol A carbonate), poly(propylene glycol) bis(2-aminopropyl ether), polyetherimide, poly(vinyl formal), poly(vinyl methyl ketone), poly(3-hexylthiophene-2,5-diyl), polyaniline, and a composite of poly(3,4-ethylenedioxythiophene) and polystyrene sulfonic acid (PEDOT:PSS).Among them, from the viewpoint of electronic interaction, polyvinyl butyral, polymethyl methacrylate, poly(3-hexylthiophene-2,5-diyl), polyvinyl acetate, polyvinyl alcohol, polyacrylic acid, poly(2-propylacrylic acid), polybutyl acrylate, and poly(4-vinylpyridine) are more preferable, and polyvinyl acetal resin and polyvinyl butyral resin are particularly preferable. In the method for producing a photoelectric conversion element of the present invention, the resin preferably contains a polyvinyl acetal resin, and more preferably contains a polyvinyl butyral resin. These resins are likely to interact with the charge transport particles.

[0042] In the method for producing a photoelectric conversion element of the present invention, the glass transition temperature of the resin is preferably 95° C. or less. Within this range, the resin is easily in close contact with the charge transport particles, and the coating property is more effectively improved by the interaction. In the present invention, the glass transition temperature can be determined by a differential scanning calorimeter (DSC).

[0043] The molecular weight of the resin is preferably in the range of 1,000 to 1,000,000 in terms of dispersibility and film-forming properties.

[0044] In the method for producing a photoelectric conversion element of the present invention, the mass of the charge transporting particles in the charge transport layer coating liquid is preferably 5 to 20 times the mass of the resin in the charge transport layer coating liquid. In this way, the resin is likely to interact with the charge transporting particles, and the covering property is likely to be improved. If it is more than 20 times, the improvement in covering property due to the interaction of the resin is likely to be insufficient. If it is less than 5 times, the charge transfer from the photoelectric conversion layer to the particles is insufficient, and it is difficult to improve the photoelectric conversion efficiency. In the present invention, the ratio of the mass of the charge transporting particles to the mass of the resin can be confirmed, for example, by taking a small amount of the charge transport layer coating liquid, dissolving it in deuterated DMSO at a low concentration, and determining the peak ratio derived from each structure by NMR measurement.

[0045] The charge transport layer coating liquid contains an alcohol liquid. The alcohol liquid functions as a dispersion medium for the charge transport particles in the coating liquid. In addition, the alcohol liquid has a low surface tension, and can exhibit good wettability of the charge transport layer coating liquid on the surface of the photoelectric conversion layer containing crystals of a perovskite structure.

[0046] In the method for producing a photoelectric conversion element of the present invention, the alcohol liquid preferably contains an aliphatic alcohol, and more preferably contains an alcohol having 5 or less carbon atoms. Within this range, the balance between the hydrophobic part and the hydrophilic part is good, and it can contribute more favorably to improving the coverage. In particular, it is preferable because it can favorably disperse particles containing a cyclic conjugated compound formed by conjugating multiple pyrrole rings, thereby improving the coverage. In addition, in the present invention, chemical substances such as alcohol liquids can be confirmed by, for example, nuclear magnetic resonance (NMR).

[0047] The alcohol liquid in the charge transport layer coating liquid may be a mixture of two or more kinds. Also, the charge transport layer coating liquid may contain a solvent other than the alcohol liquid. When a solvent other than the alcohol liquid is contained, it is preferable that the mass of the alcohol liquid is 40% or more relative to the mass of the total solvent in the charge transport layer coating liquid, since the above-mentioned effect is easily exhibited.

[0048] In the method for producing a photoelectric conversion element of the present invention, the particle diameter of the charge transporting particles in the charge transport layer coating liquid is 1.0×10 1 nm or more 5.0×10 2 If the particle size is within the above range, the dispersion stability of the charge transport particles during application is more effectively improved, and the coverage is likely to be improved.

[0049] In the present invention, the particle size of the charge transport particles in the charge transport layer coating liquid can be measured using Zetasizer Nano-ZS (manufactured by MALVERN). This device can measure the particle size by dynamic light scattering. First, the solid-liquid ratio of the particles to be measured is diluted to 0.10% by mass (±0.02% by mass), and then the solid-liquid ratio is collected in a quartz cell and placed in the measurement section. The diluted liquid is prepared and used as the same liquid as the solvent constituting the charge transport layer coating liquid. As the measurement conditions, the refractive index and viscosity of the dispersion solvent at 20°C are inputted into the control software Zetasizersoftware 6.30, and the liquid is measured under the condition of 20°C to obtain the Z-average particle size. In the case of a mixed solvent, the mass average value of the dispersion medium to be mixed is adopted.

[0050] The particle size of the charge transporting particles can be changed by dispersing the charge transport layer coating liquid with a paint shaker, and the particle size can be reduced by extending the dispersion time, and the particle size can be further reduced by centrifuging the charge transport layer coating liquid.

[0051] The charge transport layer coating liquid preferably contains an aromatic ring compound having a hydroxyl group, which is different from the charge transport particles and the resin. By containing an aromatic ring compound having a hydroxyl group, the dispersion stability of the charge transport particles during coating is more effectively improved, and the coating property is easily improved.

[0052] The charge transport layer can be formed by preparing a charge transport layer coating solution containing the above-mentioned materials and solvent, forming this coating film on the photoelectric conversion layer, and drying it. Methods for forming the coating film include dip coating, spin coating, spray coating, inkjet coating, meniscus coating, screen coating, roll coating, die coating, blade coating, curtain coating, and wire bar coating.

[0053] The photoelectric conversion element of the present invention may have a second charge transport layer between the first electrode and the charge transport layer. By having the second charge transport layer, the transfer of carriers to the electrode may be facilitated.

[0054] 〔substrate〕 The photoelectric conversion element 1 of the present invention may include a substrate 2, examples of which include a transparent glass substrate such as soda-lime glass or alkali-free glass, a ceramic substrate, a transparent plastic substrate, etc. When light is taken in from the first electrode 7 side, an opaque material can be used for the substrate 2, and when light is taken in from the second electrode 3 side, the substrate 2 is made of a transparent material.

[0055] [First electrode and second electrode] The first electrode and the second electrode can be formed by, for example, vacuum deposition, sputtering, or other known methods, such as, but not limited to, sputtering, vacuum deposition, CVD (vapor phase deposition), and SPD (spray pyrolysis deposition).

[0056] There are no particular limitations on the materials for the first electrode 7 and the second electrode 3, and any conventionally known materials can be used. Examples include metals such as gold, silver, titanium, and copper, sodium, sodium-potassium alloy, lithium, magnesium, carbon, carbon nanotubes, aluminum, magnesium-silver mixture, magnesium-indium mixture, aluminum-lithium alloy, Al / Al2O3 mixture, and Al / LiF mixture.

[0057] Examples of transparent electrode materials include conductive transparent materials such as CuI, ITO (indium tin oxide), SnO2, AZO (aluminum zinc oxide), IZO (indium zinc oxide), GZO (gallium zinc oxide), FTO (fluorine-doped tin oxide), ATO (antimony-doped tin oxide), conductive transparent polymers, etc. These materials may be used alone or in combination of two or more.

[0058] At least one of the first electrode 7 and the second electrode 3 on the light incident side is a transparent electrode, and the other may be a transparent electrode or a layer that also serves as a reflective layer made of a light-reflective material, or may be a transparent electrode provided with 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 may be a transparent electrode and the substrate 2 may be a reflective layer. The electrode may be a patterned electrode. When either 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.

[0059] When manufacturing solar cells, cutting is generally performed between each process to form circuits. Examples of cutting include mechanical patterning and laser patterning.

[0060] <Modularization process> The element having the electrodes formed thereon may be sealed. Examples of the sealing method include sealing with a resin or sealing with a film. Examples of the material used for sealing include silazane, silicone rubber, a resin having a siloxane skeleton, and glass. In addition, from the viewpoint of preventing adhesion between elements that occurs when the elements are wound in a roll-to-roll system, the surfaces of the encapsulated elements may be subjected to a hairline treatment.

[0061] [Photoelectric Conversion Layer] The method for forming the photoelectric conversion layer includes a step of applying a liquid containing the material of the photoelectric conversion layer. Examples of the application method include spin coating, blade coating, slit die coating, screen printing, bar coater, casting, print transfer, immersion and pulling, inkjet, spraying, and vacuum deposition. Among these, a method is appropriately selected according to the characteristics of the photoelectric conversion layer to be produced, such as thickness control and orientation control.

[0062] In order to remove the solvent or dispersion medium from the liquid containing the applied photoelectric conversion layer material, annealing may be performed under reduced pressure or in an inert atmosphere (nitrogen or argon atmosphere). The temperature of the annealing is preferably 40° C. or higher and 300° C. or lower, and more preferably 50° C. or higher and 150° C. or lower. Note that annealing is preferable because it may increase the contact area at the interface between the stacked layers by allowing the materials constituting each layer to penetrate into each other, thereby increasing the short-circuit current.

[0063] The photoelectric conversion layer 5 has a crystal having a perovskite structure. The crystal having a perovskite structure used in the present invention is preferably represented by the following general formula [1]. ABX3[1] In the above general formula [1], A is a monovalent cation of an organic molecule or a metal atom, B is a divalent metal cation, and X is a monovalent halide anion.

[0064] As A in the above general formula [1], for example, in the case of an organic molecule, C p N q H r (wherein p, q, and r are all positive integers) are preferable. Specific examples include methylammonium and formamidium.

[0065] The metal atom is not particularly limited, but lithium, cesium, sodium, potassium, and rubidium are preferred. These organic molecules or metal atoms may be used alone or in combination of two or more.

[0066] When the constituent A cations are too large to fit within the 3D perovskite crystal, they form 2D perovskite crystals, 2.5D perovskite crystals with both 2D and 3D properties, bilayer crystals of 3D and 2D perovskite structures, or mixed 3D and 2D perovskite crystals, all of which function as photoelectric conversion layers. A bilayer crystal of 3D and 2D perovskite is a crystal in which 3D and 2D perovskite crystals are stacked as separate layers, while a mixed 3D and 2D perovskite crystal is a crystal in which both 2D or 2.5D layered and 3D perovskite crystals are mixed.

[0067] The crystal having a two-dimensional perovskite structure or the crystal having a 2.5-dimensional perovskite structure is preferably represented by the following general formulas [2] to [4], where n is a positive integer. R'2A n-1 B n X 3n+1 [2] R''A n-1 B n X 3n+1 [3] R'''A n B n X 3n+1 [4] In the above general formulas, [2] forms an RP (Ruddlesden-Popper) type perovskite structure, [3] forms a DJ (Dion-Jacobson) type perovskite structure, and [4] forms an ACI (Alternating cations in the interlayer) type perovskite structure.

[0068] In the above general formulas [2] to [4], R', R'', and R''' are, for example, C p N m H n(p, m, and n are all positive integers). A is an organic molecule or metal cation that may have a substituent, specifically ethylammonium, propylammonium, n-butylammonium, n-hexylammonium, n-octylammonium, 1,6-hexadiammonium, iso-butylammonium, 3-(nonafluoro-tert-butyloxy)propylamine, 1,3-propanediammonium, 1,5-pentamethylenediamine, octyldiammonium, 2,2-(ethylenedioxy)bis(ethylammonium), 5-aminovaleric acid, 4-tert-butylammonium, N,N'-dimethylethylene-1,2-diammonium, 2,2,3,3,3-pentafluoropropylammonium, guanidium, propylammonium, propargylamine, alkylammonium, cyclohexylmethylammonium, 4-(aminomethyl)piperidinium, piperidinium, pyrrolidinium, cyclohexylammonium, 4- Fluorophenethylammonium, 4-fluorophenethylammonium, trifluoromethylbenzylammonium, pentafluorobenzylammonium, pentafluorophenylethylammonium, 4-methoxyphenethylammonium, imidazolium, pyridinium, 3-thiophenemethylammonium, 2-thiopheneethylammonium, 2-thiopheneformamidium, 2-thiophenemethylammonium, 1-naphthylmethylammonium, 2-naphthylmethylammonium, phenethylammonium, phenylammonium, benzylammonium, 2,5-thiophenedimethylammonium, phenylpropylammonium, 1,4-phenylenedimethanamine, 3-phenyl-2-propene-1-ammonium, phenylbutylammonium, 4-tert-butyl-benzylammonium, 3-(aminomethyl)piperidinium, 4-(aminomethyl)piperidinium are preferred.

[0069] In the above general formulas [1] to [4], B is a metal atom, such as 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, and bismuth are preferred from the viewpoint of electron orbital overlap. These metal atoms may be used alone or in combination of two or more.

[0070] X in the above general formulas [1] to [4] is a halogen atom, such as chlorine, bromine, and iodine. These halogen atoms may be used alone or in combination of two or more. Among them, halogen atoms are preferred because the perovskite crystals are easily soluble in organic solvents by containing halogen in the structure, making it possible to apply the perovskite crystals to inexpensive printing methods and the like. Furthermore, iodine is more preferred because the energy band gap of the perovskite crystals is narrowed.

[0071] Specifically, 3D perovskite crystals, 2D perovskite crystals, and mixed 3D / 2D perovskite crystals are MAPbI3, FAPbCl3, FAPbI3, MAPbI 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)<h2 style=";text-align:left;direction:ltr"> 0.85 <h2 style=";text-align:left;direction:ltr"> (MAPbBr3)<h2 style=";text-align:left;direction:ltr"> 0.15 <h2 style=";text-align:left;direction:ltr"> CsPbI3, CsPbBr3, Cs<h2 style=";text-align:left;direction:ltr"> x <h2 style=";text-align:left;direction:ltr"> (MA)<h2 style=";text-align:left;direction:ltr"> 1-x <h2 style=";text-align:left;direction:ltr"> PbI3, Csx(FA)<h2 style=";text-align:left;direction:ltr"> 1-x <h2 style=";text-align:left;direction:ltr"> PbI3, MA<h2 style=";text-align:left;direction:ltr"> x <h2 style=";text-align:left;direction:ltr"> (FA)<h2 style=";text-align:left;direction:ltr"> 1-x <h2 style=";text-align:left;direction:ltr"> PbI3, MA<h2 style=";text-align:left;direction:ltr"> 0.17 <h2 style=";text-align:left;direction:ltr"> FA<h2 style=";text-align:left;direction:ltr"> 0.83 <h2 style=";text-align:left;direction:ltr"> Pb(I<h2 style=";text-align:left;direction:ltr"> 0.83 <h2 style=";text-align:left;direction:ltr"> Br<h2 style=";text-align:left;direction:ltr"> 0.17 <h2 style=";text-align:left;direction:ltr"> 3.Cs<h2 style=";text-align:left;direction:ltr"> 0.15 <h2 style=";text-align:left;direction:ltr"> FA<h2 style=";text-align:left;direction:ltr"> 0.85 <h2 style=";text-align:left;direction:ltr"> PbI<h2 style=";text-align:left;direction:ltr"> 2.55 <h2 style=";text-align:left;direction:ltr"> Br<h2 style=";text-align:left;direction:ltr"> 0.45 <h2 style=";text-align:left;direction:ltr"> Cs<h2 style=";text-align:left;direction:ltr"> 0.05 <h2 style=";text-align:left;direction:ltr"> FA<h2 style=";text-align:left;direction:ltr"> 0.88 <h2 style=";text-align:left;direction:ltr"> MA<h2 style=";text-align:left;direction:ltr"> 0.07 <h2 style=";text-align:left;direction:ltr"> PbI<h2 style=";text-align:left;direction:ltr"> 2.56 <h2 style=";text-align:left;direction:ltr"> Br<h2 style=";text-align:left;direction:ltr"> 0.44 <h2 style=";text-align:left;direction:ltr"> Cs<h2 style=";text-align:left;direction:ltr"> 0.15 <h2 style=";text-align:left;direction:ltr"> FA<h2 style=";text-align:left;direction:ltr"> 0.85 <h2 style=";text-align:left;direction:ltr"> PbI<h2 style=";text-align:left;direction:ltr"> 2.55 <h2 style=";text-align:left;direction:ltr"> Br<h2 style=";text-align:left;direction:ltr"> 0.45 <h2 style=";text-align:left;direction:ltr"> (PEA)2(MA)2Pb3I<h2 style=";text-align:left;direction:ltr"> 10 <h2 style=";text-align:left;direction:ltr"> (PTA)2(MA)4Pb5I<h2 style=";text-align:left;direction:ltr"> 16 <h2 style=";text-align:left;direction:ltr"> (PEA)2(MA)4Pb5I<h2 style=";text-align:left;direction:ltr"> 16 <h2 style=";text-align:left;direction:ltr"> (ThMA)2(MA)2Pb3I<h2 style=";text-align:left;direction:ltr"> 10 <h2 style=";text-align:left;direction:ltr"> (3BBA)2(MA)2Pb3I<h2 style=";text-align:left;direction:ltr"> 10 <h2 style=";text-align:left;direction:ltr"> (ThMA)2(FA)4Pb5I<h2 style=";text-align:left;direction:ltr"> 16 <h2 style=";text-align:left;direction:ltr"> (4FPEA)2(FA<h2 style=";text-align:left;direction:ltr"> 0.3 <h2 style=";text-align:left;direction:ltr"> MA<h2 style=";text-align:left;direction:ltr"> 0.7 <h2 style=";text-align:left;direction:ltr"> 4Pb5I)<h2 style=";text-align:left;direction:ltr"> 16 <h2 style=";text-align:left;direction:ltr"> (PDMA)FA2Pb3I<h2 style=";text-align:left;direction:ltr"> 10 <h2 style=";text-align:left;direction:ltr"> (3AMPY)(MA)3Pb4I<h2 style=";text-align:left;direction:ltr"> 13 <h2 style=";text-align:left;direction:ltr"> (PDMA)MA5Pb6I<h2 style=";text-align:left;direction:ltr"> 19 <h2 style=";text-align:left;direction:ltr"> (PDMA)MA3Pb4I<h2 style=";text-align:left;direction:ltr"> 13 <h2 style=";text-align:left;direction:ltr"> (TTDMA)MA3Pb4I<h2 style=";text-align:left;direction:ltr"> 13 <h2 style=";text-align:left;direction:ltr"> (TTDMA)MA4Pb5I<h2 style=";text-align:left;direction:ltr"> 16 <h2 style=";text-align:left;direction:ltr"> (BA<h2 style=";text-align:left;direction:ltr"> 0.9 <h2 style=";text-align:left;direction:ltr"> PEA<h2 style=";text-align:left;direction:ltr"> 0.1 <h2 style=";text-align:left;direction:ltr"> )2MA4Pb5I<h2 style=";text-align:left;direction:ltr"> 16 <h2 style=";text-align:left;direction:ltr"> (BA<h2 style=";text-align:left;direction:ltr"> 0.9 <h2 style=";text-align:left;direction:ltr"> PEA<h2 style=";text-align:left;direction:ltr"> 0.1 <h2 style=";text-align:left;direction:ltr"> )2MA3Pb4I<h2 style=";text-align:left;direction:ltr"> 13 <h2 style=";text-align:left;direction:ltr"> (4FPEA)2MA3Pb4I<h2 style=";text-align:left;direction:ltr"> 13 <h2 style=";text-align:left;direction:ltr"> (4FPEA)2MA4Pb5I<h2 style=";text-align:left;direction:ltr"> 16 <h2 style=";text-align:left;direction:ltr"> (BA)2MA2Pb3I10 , (BA)2MA3Pb4I 13 , (TEA)2MA2Pb3I 10 , (BA)2MA4Pb5I 16 , (BA)2MA3Pb4I 13 , CsSnBr3, CsSnI3, FA 0.75 MA 0.25 Sn 0.95 Ge 0.05 I3, FAMASnGeI3, FASnBr3, FASnI3, MA2Sn3I8, MASnBr3, MASnGeI3, and MASnI3 are preferred. The A site, B site, and X site of the above general formula may be adjusted to be under- or over-adjusted depending on the purpose, and the combination of x1 to x5 may be changed depending on the purpose. The combination of x1 to x5 is shown in Table 1, for example. Particularly preferred ranges 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 may be included as a material for forming a crystal of a perovskite structure.

[0072] [Table 1]

[0073] In the above specific examples, "MA" stands for methylammonium, "FA" stands for formamidinium, "PEA" stands for phenethylammonium, "PTA" stands for phenyltriethylammonium, "ThMA" stands for 2-thiophenemethylammonium, "3BBA" stands for 3-bromobenzylammonium, "3AMPY" stands for 3-(aminomethyl)pyridine, "PDMA" stands for 1,4-phenylenedimethaneammonium, "TTDMA" stands for thieno[3,2-b]thiophene-2.5-diyldimethaneammonium, "4FPEA" stands for 4-fluorophenethylammonium, "BA" stands for butylammonium, and "TEA" stands for 2-thiophenethylammonium.

[0074] The above-mentioned perovskite crystal preferably has a cubic structure in which a metal atom B is located at the body center, an organic molecule A at each vertex, and a halogen atom X at the face center. Although the details are not clear, it is presumed that by having such a structure, the orientation of the octahedron in the crystal lattice can be easily changed, thereby increasing the mobility of electrons in the perovskite crystal and improving the photoelectric conversion efficiency of the photoelectric conversion element.

[0075] The organic-inorganic perovskite compound used in the present invention is preferably a crystalline semiconductor. The crystalline semiconductor means a semiconductor in which the scattering peak can be detected by measuring the X-ray scattering intensity distribution. By using the organic-inorganic perovskite compound as a crystalline semiconductor, the mobility of electrons in the organic-inorganic perovskite compound is increased, and the photoelectric conversion efficiency of the photoelectric conversion element is improved. Furthermore, the photoelectric conversion layer according to the present invention may contain materials other than the crystals having the organic-inorganic perovskite structure, as long as the photoelectric conversion efficiency and charge transport properties are not impaired.

[0076] The thickness of the photoelectric conversion layer according to the present invention is preferably 5 nm or more and 2000 nm or less. If the thickness is 5 nm or more, light can be sufficiently absorbed, and if the thickness is 2000 nm or less, the generated charge can be transported to each electrode. The more preferred lower limit is 50 nm or more, the more preferred upper limit is 1200 nm, the even more preferred lower limit is 100 nm, and the even more preferred upper limit is 1000 nm.

[0077] [Second Charge Transport Layer] In the present invention, from the viewpoint of film compatibility of the charge transport layer 6, a step of forming a second charge transport layer on the surface of the charge transport layer 6 (between the charge transport layer 6 and the first electrode 7) may be further included. The method of forming the second charge transport layer is as described above.

[0078] The material of the second charge transport layer is not particularly limited, and examples thereof include spirofluorene compounds, triphenylamine compounds, chrysene 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 compatibility with the film interface, it is preferable that the compound has an aromatic ring, and Spiro-OMeTAD, PTAA, and phthalocyanine compounds are preferable.

[0079] The second charge transport layer may have a dopant as an additive to improve the charge transport ability. Examples of materials that can be used as a dopant include lithium compounds such as bis(trifluoromethanesulfonyl)imide lithium, cobalt compounds such as [tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(3)tris(bis(trifluoromethylsulfonyl)imide)], boron compounds such as tetrakis(pentafluorophenyl)borate, molybdenum compounds such as tris[1-(methoxycarbonyl)-2-(trifluoromethyl)-ethane-1,2-dithiolene]molybdenum, organic compounds having a tetracyanoquinodimethane skeleton such as 2,3,4,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane, and organic compounds having a pyridine skeleton such as 4-tert-butylpyridine.

[0080] [Electron transport layer] In the photoelectric conversion element of the present invention, as shown in FIG. 1, an electron transport layer 4 may be disposed between the second electrode 3 and the photoelectric conversion layer 5.

[0081] The material of the electron transport layer 4 is not particularly limited, and examples thereof include N-type conductive polymers, N-type low-molecular organic semiconductors, N-type metal oxides, N-type metal sulfides, alkali metal halides, alkali metals, surfactants, etc. Specific examples thereof include cyano group-containing polyphenylene vinylene, boron-containing polymers, bathocuproine, bathophenanthrene, hydroxyquinolinatoaluminum, oxadiazole compounds, benzimidazole compounds, naphthalenetetracarboxylic acid compounds, fullerene compounds, perylene derivatives, phosphine oxide compounds, phosphine sulfide compounds, fluoro group-containing phthalocyanines, titanium oxide, zinc oxide, indium oxide, tin oxide, gallium oxide, tin sulfide, indium sulfide, zinc sulfide, etc. In particular, tin oxide may be obtained by reacting tin chloride (2), tin chloride (4), tin chloride (2) dihydrate, or tin chloride (4) pentahydrate.

[0082] The thickness of the electron transport layer 4 is preferably 1 nm at the lower limit and 2000 nm at the upper limit. If the thickness is 1 nm or more, holes can be blocked sufficiently, and if the thickness is 2000 nm or less, the layer is unlikely to become a resistance during electron transport, and the photoelectric conversion efficiency is increased. The more preferable lower limit of the thickness is 3 nm, the more preferable upper limit is 1000 nm, the even more preferable lower limit is 5 nm, and the even more preferable upper limit is 500 nm.

[0083] <Photoelectric conversion elements and their applications> The photoelectric conversion element produced by the method for producing a photoelectric conversion element of the present invention and its application examples will be described below.

[0084] [Photoelectric conversion element] The photoelectric conversion element of the present invention is manufactured by the above-mentioned method for manufacturing a photoelectric conversion element. The photoelectric conversion element 1 has a second electrode 3, an electron transport layer 4, a photoelectric conversion layer 5, a charge transport layer 6, and a first electrode 7 on a substrate 2. One of the first electrode 7 and the second electrode 3 is an anode and the other is a cathode, and a current can be extracted by connecting the first electrode 7 and the second electrode 3 to an external circuit.

[0085] The photoelectric conversion layer 5 is excited by light incident through the substrate 2, the second electrode 3, and the electron transport layer 4, or through the first electrode 7 and the charge transport layer 6, and generates 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 a layer disposed between the photoelectric conversion layer 5 and two electrodes (the second electrode 3 and the first electrode 7), and may not be formed in some cases. A configuration in which a plurality of electron transport layers 4 and photoelectric conversion layers 5 are stacked may be used. Such a configuration may be called a tandem structure.

[0086] The photoelectric conversion element of the present invention is characterized by having a first electrode 7, a second electrode 3, a photoelectric conversion layer 5 containing a crystal of a perovskite structure disposed between the first electrode 7 and the second electrode 3, and a charge transport layer 6 between the photoelectric conversion layer 5 and the first electrode 7. In order to improve the photoelectric conversion efficiency, the photoelectric conversion elements 1 may be stacked in a tandem type. The photoelectric conversion elements to be stacked are not limited to the type of photoelectric conversion element, and may be a silicon solar cell, a CIGS solar cell, or the like, in addition to a perovskite solar cell using a crystal of a perovskite structure for the photoelectric conversion layer 5.

[0087] In the photoelectric conversion element of the present invention, it is preferable that a charge transport layer 6 is disposed between the photoelectric conversion layer 5 and the first electrode 7, the charge transport layer 6 having charge transport particles and a resin, and disposed on the surface of the photoelectric conversion layer 5. The film thickness of the charge transport layer 6 is preferably 1 nm or more and 1000 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.

[0088] The thickness of the photoelectric conversion layer is preferably 5 nm or more and 2000 nm or less. If the thickness is 5 nm or more, light can be sufficiently absorbed, and if the thickness is 2000 nm or less, the generated charge can be transported to each electrode. The more preferred lower limit is 50 nm or more, the more preferred upper limit is 1200 nm, the even more preferred lower limit is 100 nm, and the even more preferred upper limit is 1000 nm.

[0089] In the present invention, the presence of each layer can be confirmed, for example, by X-ray photoelectron spectroscopy (XPS), nuclear magnetic resonance (NMR), or energy dispersive X-ray spectroscopy (EDS) using an electron gun of a scanning electron microscope (SEM) or a transmission electron microscope (TEM). The shape and aspect ratio of the charge transporting particles can also be confirmed by a scanning electron microscope (SEM) or a transmission electron microscope (TEM). In the present invention, the film thickness of each layer can be confirmed, for example, by observing a cross section of a photoelectric conversion element with a scanning electron microscope (SEM) or a transmission electron microscope (TEM).

[0090] [Photoelectric conversion device] The photoelectric conversion device of the present invention includes the above-mentioned photoelectric conversion element. A photoelectric conversion device can be configured by using a plurality of the photoelectric conversion elements of the present invention. When a plurality of photoelectric conversion elements are connected, the photoelectric conversion device can be called a photoelectric conversion cell or a photoelectric conversion module.

[0091] The photoelectric conversion element may be stacked with photoelectric conversion elements having different absorption wavelengths in order to increase the output voltage. The photoelectric conversion device has the photoelectric conversion element of the present invention and an inverter. The inverter may be a converter that converts direct current to alternating current. The photoelectric conversion device may have a storage unit connected to the photoelectric conversion element. The storage unit is not limited as long as it can store electricity. For example, a secondary battery using lithium ions or the like, an all-solid-state battery, an electric double layer capacitor, etc. may be mentioned. In order to impart a function such as maintaining or increasing the amount of incident light, a surface layer that is resistant to water and dirt, or a function of collecting or guiding light may be added.

[0092] [Mobile object] The moving body of the present invention has the above-mentioned photoelectric conversion element. Fig. 2 is a perspective view showing an embodiment of a moving body having the photoelectric conversion element of the present invention. The moving body 30 has the photoelectric conversion element 31 of the present invention and a body 32 having the photoelectric conversion element 31.

[0093] The photoelectric conversion element 31 is disposed at a position on the body 32 where it can receive external light. If the moving body 30 is an automobile, it may be disposed on the roof. The electric energy obtained by the photoelectric conversion element 31 may power the moving body 30 or may power other electric devices. The electric energy generated from the power of the moving body 30 may be used to power the photoelectric conversion element 31. If the moving body 30 is an automobile, frictional energy generated by braking may be converted into electric energy and used to control the photoelectric conversion element 31.

[0094] The moving body 30 may be, for example, an automobile, a motorcycle, a railroad vehicle, a ship, an artificial satellite, an airplane, or a flying object including a drone. The configuration of the body 32 of the moving body 30 is not particularly limited, but it is preferable that the body 32 be made of a high-strength material.

[0095] [Building materials] The building material of the present invention has the above-mentioned photoelectric conversion element. Fig. 3 is a perspective view showing an 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 has the photoelectric conversion element 41 of the present invention, a protective member 42 that protects the photoelectric conversion element 41, a heat dissipation member 43, and exteriors 44a and 44b.

[0096] The building material 40 of the present invention may have a heat dissipation member 43 having a higher thermal conductivity than the photoelectric conversion element 41. When used on a roof or the like, the temperature of the photoelectric conversion element 41 may increase due to sunlight, and the photoelectric conversion efficiency may decrease. The use of the heat dissipation member 43 can reduce the decrease in photoelectric conversion efficiency. Examples of the heat dissipation member 43 include metal, alloy, liquid metal, and liquid resin.

[0097] Furthermore, the building material 40 of the present invention may have exteriors 44a and 44b. The exteriors 44a and 44b may emit different colors or may be the same. 44a and 44b may be made of the same material or different materials. Paint or a transparent substrate may be used as the exterior. A material with low light absorption and high heat insulation is preferable.

[0098] In addition to the above application examples, other application examples include the following: Portable devices, such as calculators, sensors, and small solar panels. Wearable devices, such as eyeglass-type terminals, wristwatch-type terminals, and portable medical equipment. Sheet structures supported by multiple frames, such as tents, vinyl greenhouses, and truck beds. Fixed structures, such as road panels, floating panels, building materials that take advantage of the flexibility of the substrate, wall-type building materials, glass-type building materials, and mega solar panels. EXAMPLES

[0099] The present invention will be described in more detail below using examples and comparative examples. The present invention is not limited to the following examples without departing from the gist of the present invention. In the following examples, "parts" are by mass unless otherwise specified.

[0100] Preparation of particle 1 Process (1) In a nitrogen flow atmosphere, 5.46 parts of orthophthalonitrile and 45 parts of α-chloronaphthalene were added to a reaction vessel, which was then heated to a temperature of 30°C and maintained at this temperature. Next, 3.75 parts of gallium trichloride were added at this temperature (30°C). The water concentration of the mixture at the time of addition was 150 ppm. The temperature was then increased to 200°C.

[0101] Next, the mixture was reacted at 200°C for 4.5 hours under a nitrogen flow atmosphere, then cooled, and the product was filtered when the temperature reached 150°C. The resulting filtrate was dispersed and washed using N,N-dimethylformamide at 140°C for 2 hours, and then filtered. The resulting filtrate was washed with methanol and dried to obtain chlorogallium phthalocyanine particles in a yield of 71% by mass.

[0102] Process (2) 4.65 parts of the chlorogallium phthalocyanine particles were dissolved in 139.5 parts of concentrated sulfuric acid at a temperature of 10° C., dropped into 620 parts of ice water under stirring to reprecipitate, and filtered under reduced pressure using a filter press. No. 5C (manufactured by Advantec Co., Ltd.) was used as the filter. The obtained wet cake (filtrate) was dispersed and washed with 2% ammonia water for 30 minutes, and then filtered using a filter press.

[0103] Next, the obtained wet cake (filtrate) was dispersed and washed with ion-exchanged water, and then filtered three times using a filter press. Finally, freeze-drying was performed to obtain hydroxygallium phthalocyanine particles (hydrated hydroxygallium phthalocyanine particles) with a solid content of 23% by mass at a yield of 71% by mass. These hydroxygallium phthalocyanine particles were dried in a Hyper Dry dryer (product name: HD-06R, frequency (oscillation frequency): 2455MHz ± 15MHz, manufactured by Japan Biocon) to obtain hydroxygallium phthalocyanine (OHGaPc) particles (crystals) with a water content of 1.0% by mass or less.

[0104] Process (3) Five parts of the hydroxygallium phthalocyanine particles were mixed with five parts of N-methylformamide solvent, and the mixture was dispersed for six hours using a sand mill (TSG-1 / 4G-4U, manufactured by Igarashi Machine Manufacturing (now Imex), disk diameter 70 mm, number of disks 5) containing five parts of glass beads, filtered, and dried to obtain Particle 1 (specific gravity 1.6). The aspect ratio was 3 or less.

[0105] Preparation of resin solution 1 1.0 g of polyvinyl acetal resin (product name: S-LEC (registered trademark) BM-2, manufactured by Sekisui Chemical Co., Ltd., glass transition temperature 71° C.) was dissolved in 19 g of 2-propanol as a solvent with stirring for 24 hours to obtain resin solution 1.

[0106] Preparation of resin solution 2 1.0 g of polyvinyl acetal resin (product name: S-LEC (registered trademark) BX-1, manufactured by Sekisui Chemical Co., Ltd., glass transition temperature 95° C.) was dissolved in 19 g of ethanol as a solvent with stirring for 24 hours to obtain resin solution 2.

[0107] Preparation of resin solution 3 1.0 g of polyvinyl acetal resin (product name: S-LEC (registered trademark) BL-S, manufactured by Sekisui Chemical Co., Ltd., glass transition temperature 66° C.) was dissolved in 19 g of 2-propanol as a solvent with stirring for 24 hours to obtain resin solution 3.

[0108] Preparation of resin solution 4 1.0 g of polymethyl methacrylate (PMMA, manufactured by Sigma-Aldrich, glass transition temperature 70° C.) was dissolved in 19 g of chlorobenzene as a solvent with stirring for 24 hours to obtain resin solution 4.

[0109] Preparation of resin solution 5 1.0 g of polymethyl methacrylate (PMMA, manufactured by Sigma-Aldrich, glass transition temperature 100° C.) was dissolved in 19 g of chlorobenzene as a solvent with stirring for 24 hours to obtain resin solution 5.

[0110] Preparation of resin solution 6 1.0 g of poly(3-hexylthiophene-2,5-diyl) (P3HT, glass transition temperature 130° C.) was dissolved in 19 g of chlorobenzene as a solvent with stirring for 24 hours to obtain a resin solution 6.

[0111] Preparation of resin solution 7 1.0 g of poly(4-vinylpyridine) (glass transition temperature: 137° C.) was dissolved in 19 g of 2-propanol as a solvent with stirring for 24 hours to obtain resin solution 7.

[0112] Preparation of resin solution 8 1.0 g of poly[9,9-bis-(2-ethylhexyl)-9H-fluorene-2,7-diyl] (glass transition temperature: 45° C.) was dissolved in 19 g of chlorobenzene as a solvent with stirring for 24 hours to obtain a resin solution 8.

[0113] <Preparation of resin solution 9> 1.0 g of poly(3-hexylthiophene-2,5-diyl) (P3HT, glass transition temperature 130° C.) was dissolved in 19 g of dichlorobenzene as a solvent with stirring for 24 hours to obtain resin solution 9.

[0114] Preparation of resin solution 10 1.0 g of polyvinyl acetal resin (product name: S-LEC (registered trademark) BL-S, manufactured by Sekisui Chemical Co., Ltd., glass transition temperature 66° C.) was dissolved in 19 g of acetone as a solvent with stirring for 24 hours to obtain a resin solution 10.

[0115] Example 1 [Formation of Electron Transport Layer] A glass substrate with ITO was cleaned, and a 5-fold diluted tin oxide (2) colloidal solution (15% water dispersion, manufactured by Alfa Aesar) was spin-coated onto it, and then heated at 150°C for 30 minutes to form a thin-film electron transport layer with a thickness of 16 nm.

[0116] [Formation of photoelectric conversion layer] 1.1 g of lead iodide and 0.39 g of methylammonium iodide were dissolved in 0.36 g of N,N-dimethylformamide and 1.45 g of dimethylsulfoxide to prepare a photoelectric conversion layer coating solution. This coating solution was spin-coated on the electron transport layer to form a 500 nm-thick photoelectric conversion layer made of MAPbI3.

[0117] [Formation of Charge Transport Layer] 0.1g of the particles 1 and 0.01g of a calixarene compound (JP Patent Publication 2003-207913) were mixed with 10.6g of 2-propanol as a solvent, and 11g of beads (zirconia beads, Treceram (registered trademark) zirconia beads, 0.3mm) were enclosed in this mixture, and dispersion was performed for 3 hours using a paint shaker (manufactured by Toyo Seiki Co., Ltd.). Then, 0.2g of resin solution 1 was added, and dispersion was performed again for 4 hours using a paint shaker to prepare a charge transport layer coating liquid. This charge transport layer coating liquid was spin-coated on the photoelectric conversion layer to form a charge transport layer having a thickness of 180nm.

[0118] [Introduction of a second charge transport layer] 0.15 g of Spiro-OMeTAD 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 this chlorobenzene solution and 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(3)tris(bis(trifluoromethylsulfonyl)imide)] in 0.3 g of acetonitrile was mixed to prepare a material solution for the second charge transport layer. This was applied by spin coating on the charge transport layer to form a second charge transport layer with a thickness of 150 nm.

[0119] [Formation of the first electrode] On the second charge transport layer, a layer having a thickness of 80 nm and an area of ​​0.36 cm 2 A gold electrode was formed by vacuum deposition to obtain a photoelectric conversion element.

[0120] [Analysis of compound amounts] The electrode surface of the photoelectric conversion element was peeled off to expose the charge transport layer surface. This charge transport layer surface was wiped off with a cotton swab or the like soaked in a solvent, dissolved in heavy water sulfuric acid, and 1H-NMR measurement (apparatus: AVANCE3-500, manufactured by BRUKER) was performed. In addition, the peeled off charge transport layer components were subjected to mass and structure analysis by elemental analysis such as GPC, MALDI-TOF-MS, IR, gas chromatography, XPS, and EDX to confirm the presence of compounds. The film thickness was confirmed by cutting the photoelectric conversion element, fixing it to an inclined sample stage, and then observing the cross-section with a SEM (apparatus: Carl Zeiss, SmartSEM).

[0121] [Analysis of particle size of charge transport particles] The particle size of the charge transporting particles in the charge transport layer coating solution was determined by measuring the Z-average particle size using the above-mentioned Zetasizer Nano-ZS (manufactured by MALVERN).

[0122] Example 2 A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, the amount of resin solution 1 added is changed to 0.25 g.

[0123] Example 3 A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, the amount of resin solution 1 added is changed to 0.40 g.

[0124] Example 4 A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, the amount of resin solution 1 added is changed to 0.10 g.

[0125] Example 5 A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, the amount of resin solution 1 added is changed to 0.50 g.

[0126] Example 6 A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, the amount of resin solution 1 added is changed to 0.08 g.

[0127] Example 7 In preparing the charge transport layer coating solution, the time of paint shaker dispersion before adding resin solution 1 was changed to 6 hours, and the obtained dispersion was centrifuged (15,000 rpm, 2 minutes) to reduce the particle size in the dispersion, and then resin solution 1 was added so that the mass ratio of the charge transport particles to the resin was 10 times, and the photoelectric conversion element was obtained in the same manner as in Example 1, except that the paint shaker dispersion was again performed for 4 hours.

[0128] Example 8 In preparing the charge transport layer coating solution, the time for dispersion in the paint shaker before adding resin solution 1 was changed to 1 hour, and the time for dispersion in the paint shaker after adding resin solution 1 was changed to 1 hour. A photoelectric conversion element was obtained in the same manner as in Example 1.

[0129] Example 9 A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, 10.6 g of 2-propanol is changed to 10.6 g of ethanol and resin solution 1 is changed to resin solution 2.

[0130] Example 10 A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, the particles 1 are changed to copper phthalocyanine particles.

[0131] Example 11 A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, the particles 1 are changed to tetraphenylporphyrin (TPP) particles.

[0132] Example 12 A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, the particles 1 are changed to quinacridone particles.

[0133] (Example 13) A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, particles 1 are changed to particles having a compound represented by the following formula (Pc-3). [ka]

[0134] Example 14 A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, resin solution 1 is changed to resin solution 4.

[0135] Example 15 A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, resin solution 1 is changed to resin solution 5.

[0136] Example 16 A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, resin solution 1 is changed to resin solution 3.

[0137] (Example 17) A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, resin solution 1 is changed to resin solution 6.

[0138] (Example 18) A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, resin solution 1 is changed to resin solution 7.

[0139] (Example 19) A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, the amount of resin solution 1 added is 0.25 g and the second charge transport layer is not provided.

[0140] (Example 20) A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, the solvent is changed to 4.2 g of 2-propanol and 6.4 g of chlorobenzene.

[0141] Example 21 A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, 10.6 g of 2-propanol is changed to 10.6 g of methanol.

[0142] Example 22 A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, 10.6 g of 1-butanol is used instead of 10.6 g of 2-propanol.

[0143] Example 23 A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, 10.6 g of 2-propanol is replaced with 10.6 g of 1-pentanol.

[0144] Example 24 A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, 10.6 g of 2-propanol is changed to 10.6 g of benzyl alcohol.

[0145] (Example 25) A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, resin solution 8 is used instead of resin solution 1, and the amount added is changed to 0.14 g.

[0146] (Example 26) A photoelectric conversion element is obtained in the same manner as in Example 1, except that the photoelectric conversion layer coating liquid is changed as follows to form the photoelectric conversion layer. 0.487g of methylammonium bromide, 1.034g of formamidium iodide, 2.903g of lead iodide, and 0.139g of methylammonium bromide are dissolved in 4.25g of N,N-dimethylformamide and 1.216g of dimethyl sulfoxide, and the mixture is stirred for 1 hour (solution 1). Furthermore, 0.100g of cesium iodide is dissolved in 0.285g of dimethyl sulfoxide, and the mixture is stirred for 1 hour (solution 2). The dissolved cesium iodide solution (solution 2) is then added to solution 1 to prepare a photoelectric conversion layer coating solution. This coating solution is spin-coated on the electron transport layer to produce Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 ) 3 to form a photoelectric conversion layer having a thickness of 600 nm.

[0147] Comparative Example 1 A photoelectric conversion element was obtained in the same manner as in Example 1, except that resin solution 1 was not used in the preparation of the charge transport layer coating solution.

[0148] Comparative Example 2 In preparing the charge transport layer coating solution, a photoelectric conversion element is obtained in the same manner as in Example 1, except that the particles 1 are replaced with particles having a compound represented by the following formula (Pc-4), 10.6 g of 2-propanol is replaced with 10.6 g of dichlorobenzene, resin solution 1 is replaced with resin solution 9, and the solvent is replaced with only dichlorobenzene. [ka]

[0149] Comparative Example 3 A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, 10.6 g of 2-propanol is changed to 10.6 g of acetone, resin solution 1 is changed to resin solution 10, and the solvent is acetone only.

[0150] Comparative Example 4 A photoelectric conversion element is obtained in the same manner as in Example 1, except that in the preparation of the charge transport layer coating solution, 10.6 g of 2-propanol is changed to 10.6 g of chlorobenzene (solvent is only chlorobenzene) and resin solution 1 is not used.

[0151] Comparative Example 5 In preparing the charge transport layer coating solution, the particles 1 were changed to nickel(II) phthalocyanine-tetrasulfonic acid tetrasodium salt, the 10.6 g of 2-propanol was changed to 10.6 g of water, the resin solution 1 was changed to PEDOT:PSS (2.7% by mass, manufactured by Sigma-Aldrich Co.) and the amount added was changed to 0.37 g, and the solvent was changed to water only. Except for this, a photoelectric conversion element was obtained in the same manner as in Example 1.

[0152] Comparative Example 6 In preparing the charge transport layer coating solution, a photoelectric conversion element is obtained in the same manner as in Example 1, except that 10.6 g of 2-propanol is changed to 10.6 g of chlorobenzene, particles 1 are changed to Spiro-OMeTAD, resin solution 1 is changed to resin solution 5, and the solvent is changed to only chlorobenzene.

[0153] [evaluation] A power supply (KEITHLEY, Model 236) was connected between the electrodes of the photoelectric conversion element prepared in Example 1, and the intensity was 100 mW / cm 2 The photoelectric conversion efficiency was measured by irradiating the device with a constant amount of light using a solar simulator (manufactured by Yamashita Denso Co., Ltd.) and measuring the generated current and voltage. The results are shown in Table 2.

[0154] The photoelectric conversion efficiency of each of Examples 2 to 26 and Comparative Examples 1 to 6 was evaluated in the same manner as in Example 1. The results are shown in Table 2. In Table 2, the photoelectric conversion efficiency in Example 1 is set to 100, and the ratio to this is shown as the conversion efficiency of each photoelectric conversion element. In Comparative Examples 5 and 6, the charge transport material was dissolved in a solvent, and the particles were not in a dispersed state, so that the particle size was not measured.

[0155] [Table 2]

[0156] The disclosure of this embodiment includes the following method. (Method 1) A method for producing a photoelectric conversion element having a first electrode, a photoelectric conversion layer including a crystal having a perovskite structure, a charge transport layer, and a second electrode, comprising the steps of: A step of applying a charge transport layer coating liquid onto a surface of the photoelectric conversion layer to form a charge transport layer, The method for producing a photoelectric conversion element, wherein the charge transport layer coating liquid contains an alcohol liquid, a resin, and charge transport particles. (Method 2) The method for producing a photoelectric conversion element according to method 1, wherein the alcohol liquid contains an aliphatic alcohol. (Method 3) 3. The method for producing a photoelectric conversion element according to method 1 or 2, wherein the alcohol liquid contains an alcohol having 5 or less carbon atoms. (Method 4) The method for producing a photoelectric conversion element according to any one of Methods 1 to 3, wherein the resin is a resin having a Lewis basic functional group. (Method 5) The method for producing a photoelectric conversion element according to any one of Methods 1 to 4, wherein the resin has at least one functional group selected from the group consisting of a hydroxy group, a carbonyl group, an ether group, an ester group, a pyridyl group, and a thienylidene group. (Method 6) 6. The method for producing a photoelectric conversion element according to any one of Methods 1 to 5, wherein the resin includes a polyvinyl acetal resin. (Method 7) 7. The method for producing a photoelectric conversion element according to any one of Methods 1 to 6, wherein the resin has a glass transition temperature of 95° C. or lower. (Method 8) The method for producing a photoelectric conversion element according to any one of Methods 1 to 7, wherein the mass of the charge transport particles in the charge transport layer coating liquid is 5 to 20 times the mass of the resin in the charge transport layer coating liquid. (Method 9) The particle size of the charge transport particles in the charge transport layer coating liquid is 1.0×10 1 nm or more 5.0×10 2 9. The method for producing a photoelectric conversion element according to any one of methods 1 to 8, wherein the thickness of the photoelectric conversion element is 10 nm or less. (Method 10) 10. The method for producing a photoelectric conversion element according to any one of Methods 1 to 9, wherein the charge transporting particles are particles containing a cyclic conjugated compound in which a plurality of pyrrole rings are conjugated. (Method 11) 11. The method for producing a photoelectric conversion element according to any one of Methods 1 to 10, wherein the charge transporting particles are particles containing a phthalocyanine compound. (Method 12) 12. The method for producing a photoelectric conversion element according to any one of Methods 1 to 11, wherein the charge transporting particles are particles having a structure represented by the following formula (Pc-2): [ka] (In the above formula (Pc-2), M represents H2, a metal atom having a ligand, or a metal atom having no ligand.) (Method 13) 13. The method for producing a photoelectric conversion element according to any one of Methods 1 to 12, further comprising the step of forming a second charge transport layer on a surface of the charge transport layer. [Explanation of symbols]

[0157] 1 Photoelectric conversion element 2. Board 3 Second electrode 4 Electron transport layer 5 Photoelectric conversion layer 6 Charge transport layer 7 First electrode 30 Mobile 31, 41 Photoelectric conversion element 32 Aircraft 40 Building materials 42 Protective materials 43 Heat dissipation materials 44a, 44b Exterior

Claims

1. A method for producing a photoelectric conversion element having a first electrode, a photoelectric conversion layer including a crystal having a perovskite structure, a charge transport layer, and a second electrode, comprising the steps of: A step of applying a charge transport layer coating liquid onto a surface of the photoelectric conversion layer to form a charge transport layer, The method for producing a photoelectric conversion element, wherein the charge transport layer coating liquid contains an alcohol liquid, a resin, and charge transport particles.

2. The method for producing a photoelectric conversion element according to claim 1 , wherein the alcohol liquid contains an aliphatic alcohol.

3. The method for producing a photoelectric conversion element according to claim 1 , wherein the alcohol liquid contains an alcohol having 5 or less carbon atoms.

4. The method for producing a photoelectric conversion element according to claim 1 , wherein the resin has a Lewis basic functional group.

5. The method for producing a photoelectric conversion element according to claim 1 , wherein the resin has at least one functional group selected from the group consisting of a hydroxy group, a carbonyl group, an ether group, an ester group, a pyridyl group, and a thienylidene group.

6. The method for producing a photoelectric conversion element according to claim 1 , wherein the resin includes a polyvinyl acetal resin.

7. The method for producing a photoelectric conversion element according to claim 1 , wherein the resin has a glass transition temperature of 95° C. or lower.

8. 2 . The method for producing a photoelectric conversion element according to claim 1 , wherein the mass of the charge transporting particles in the charge transport layer coating liquid is 5 to 20 times the mass of the resin in the charge transport layer coating liquid.

9. The particle size of the charge transport particles in the charge transport layer coating liquid is 1.0×10 １ nm or more 5.0×10 ２ The method for producing a photoelectric conversion element according to claim 1 , wherein the thickness of the first and second electrodes is equal to or less than nm.

10. The method for producing a photoelectric conversion element according to claim 1 , wherein the charge transporting particles are particles containing a cyclic conjugated compound in which a plurality of pyrrole rings are conjugated.

11. The method for producing a photoelectric conversion element according to claim 1 , wherein the charge transporting particles are particles containing a phthalocyanine compound.

12. 2. The method for producing a photoelectric conversion element according to claim 1, wherein the charge transporting particles are particles having a structure represented by the following formula (Pc-2): 【Chemistry 1】 (In the above formula (Pc-2), M represents H2, a metal atom having a ligand, or a metal atom having no ligand.)

13. The method for producing a photoelectric conversion element according to claim 1 , further comprising the step of forming a second charge transport layer on a surface of the charge transport layer.

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