Laminate, photoelectric conversion element, method for manufacturing laminate, and method for manufacturing photoelectric conversion element

Abstract

[Problem] To provide a laminate, a photoelectric conversion element, a method for manufacturing a laminate, and a method for manufacturing a photoelectric conversion element with which it is possible to suppress deterioration of an electrode and an electron transport layer and to output a high current value or a high voltage value. [Solution] A laminate for forming a photoelectric conversion element 1 by laminating a photoelectric conversion layer 50 containing a perovskite compound having a perovskite crystal structure, the laminate comprising a substrate 10, an electrode 20 laminated on the substrate 10, and an electron transport layer 30 laminated on the electrode 20, wherein the electron transport layer 30 contains semiconductor fine particles and a water-dispersible resin.

Description

Laminate, photoelectric conversion element, method for manufacturing a laminate, and method for manufacturing a photoelectric conversion element

[0001] The present invention relates to a laminate used in the manufacture of a photoelectric conversion element using a perovskite compound, a photoelectric conversion element having the laminate, a method for manufacturing the laminate, and a method for manufacturing the photoelectric conversion element.

[0002] In recent years, photoelectric conversion materials with a perovskite crystal structure using lead, tin, etc. as the central metal, known as organic-inorganic hybrid semiconductors, have been discovered and demonstrated to have high photoelectric conversion efficiency (for example, Non-Patent Document 1).

[0003] M. M. Lee et al. , Science, 338, 643-647 (2012)

[0004] Photoelectric devices using perovskite compounds having a perovskite crystal structure as photoelectric conversion materials are generally manufactured by forming transparent electrodes on a substrate by depositing ITO transparent electrodes or silver nanowires, and then sequentially stacking an electron transport layer, a photoelectric conversion layer containing a perovskite compound, a hole transport layer, and a metal electrode on top of that. Furthermore, the photoelectric conversion layer made of a perovskite compound having a perovskite crystal structure can be formed by coating or printing techniques. It can be formed by forming an electron transport layer on a transparent electrode with deposited ITO transparent electrodes or silver nanowires, and then coating the electron transport layer with a solution containing a perovskite precursor and heating and drying it.

[0005] However, it has been found that when photoelectric devices are fabricated in this way, the perovskite solution containing the perovskite precursor acts on the underlying electron transport layer and transparent electrode, degrading the components contained in the electron transport layer and transparent electrode, which can result in insufficient current or voltage being obtained in the fabricated photoelectric device. Furthermore, this phenomenon can occur whether the transparent electrode is an ITO transparent electrode or a transparent electrode with deposited silver nanowires, but it is particularly pronounced in transparent electrodes with deposited silver nanowires.

[0006] This invention was created in view of the above problems, and aims to provide a laminate, a photoelectric conversion element, a method for manufacturing the laminate, and a method for manufacturing the photoelectric conversion element, in which the degradation of electrodes and electron transport layers is suppressed and high voltage or current can be output.

[0007] The present invention is characterized by the following laminates (1) to (5): (1) A laminate for forming a photoelectric element by laminating photoelectric conversion layers containing a perovskite compound having a perovskite crystal structure, comprising a substrate, an electrode laminated on the substrate, and an electron transport layer laminated on the electrode, wherein the electron transport layer contains semiconductor nanoparticles and an aqueous dispersible resin. (2) The laminate according to (1) above, wherein the aqueous dispersible resin is a polyolefin resin. (3) The laminate according to (1) above, wherein the aqueous dispersible resin is a resin in which at least a part of the acid structure is neutralized by a volatile alkaline component. (4) The laminate according to (1) above, wherein the content of the aqueous dispersible resin is 5 to 35% by weight relative to the content of the semiconductor nanoparticles. (5) The laminate according to (1) above, wherein the electrode contains conductive nanowires. The present invention is also characterized by the following photoelectric element (6). (6) A photoelectric conversion element having a laminate as described in any of (1) to (5) above. Furthermore, the present invention is characterized by a method for manufacturing a laminate as described in (7) below. (7) A method for manufacturing a laminate for forming a photoelectric conversion element by laminating a photoelectric conversion layer containing a perovskite compound having a perovskite crystal structure, wherein the laminate comprises a substrate, an electrode laminated on the substrate, and an electron transport layer laminated on the electrode, and the method comprises a step of forming an electron transport layer on the electrode, wherein the electron transport layer is formed using an ink composition containing semiconductor fine particles and an aqueous dispersion resin. In addition, the present invention is characterized by a method for manufacturing a photoelectric conversion element as described in (8) below. (8) A method for manufacturing a photoelectric conversion element, wherein a photoelectric conversion layer containing a perovskite compound having a perovskite crystal structure is formed on the electron transport layer of the laminate manufactured by the method for manufacturing a laminate as described in (7) above, using a solution containing a perovskite precursor.

[0008] According to the present invention, since the electron transport layer contains a water-dispersible resin binder, degradation of the electrodes and electron transport layer by the perovskite solution applied on the electron transport layer when forming the photoelectric conversion layer is suppressed, and a laminate capable of outputting high current or voltage, a photoelectric conversion element, a method for manufacturing the laminate, and a method for manufacturing the photoelectric conversion element can be provided.

[0009] This is a cross-sectional view showing the photoelectric conversion element according to this embodiment. This is a flowchart showing the method for manufacturing the photoelectric conversion element according to this embodiment. This is a diagram illustrating the method for manufacturing the photoelectric conversion element according to this embodiment. This is an image showing the verification results in Test Example 2.

[0010] Embodiments of the present invention are described below. In this invention, "perovskite compound" refers to a compound having a perovskite crystal structure. In this invention, a configuration having a photoelectric conversion layer containing a perovskite compound and electrodes for guiding out electrons generated in the photoelectric conversion layer is referred to as a photoelectric conversion element, and a device having such a photoelectric conversion element and functioning as a battery is referred to as a perovskite solar cell. A photoelectric conversion element is a device that converts light energy into electrical energy and can be used as part of solar cells or sensors. In this embodiment, a planar-type and mesoporous photoelectric conversion element is used as an example, but the present invention is not limited to planar-type and mesoporous photoelectric conversion elements, and can also be applied to planar-type photoelectric conversion elements without a mesoporous structure, and to inverted-type (OPV) photoelectric conversion elements.

[0011] Figure 1 is a cross-sectional view showing a photoelectric conversion element 1 according to this embodiment. As shown in Figure 1, the photoelectric conversion element 1 according to this embodiment includes a substrate 10, a first electrode 20, an electron transport layer 30, a porous layer 40, a photoelectric conversion layer 50, a hole transport layer 60, a second electrode 70, and a wiring layer 80. In this embodiment, a photoelectric conversion element 1 that receives light from the substrate 10 side and generates electrons in the photoelectric conversion layer 50 based on the incident light is described as an example, but the photoelectric conversion element of the present invention is not limited to this configuration, and a configuration in which light is received from the second electrode 70 side is also possible. In this embodiment, the configuration having the substrate 10, the first electrode 20, and the electron transport layer 30 is also referred to as a laminate 2. The laminate 2 only needs to have at least the first electrode 20 and the electron transport layer 30, and for example, it can further include a porous layer 40, or it can further include a photoelectric conversion layer 50. Furthermore, the laminate 2 can be provided independently as a component (part) for manufacturing the photoelectric conversion element 1 according to this embodiment.

[0012] (Substrate 10) The substrate 10 is a component that supports each layer of the photoelectric conversion element 1. The substrate 10 is preferably made of a material that does not deteriorate due to heat or organic solvents. Furthermore, the substrate 10 is preferably flexible. The material of the substrate 10 is not particularly limited, but examples include substrates containing inorganic materials, plastic substrates, polymer films, or metal substrates. Examples of inorganic materials include alkali-free glass and quartz glass. For plastics and polymer films, polyolefin resins such as polyethylene, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyimide resins such as polyimide, polyamide, and polyamide-imide, acrylic resins, fluororesins, liquid crystal polymers, and cycloolefin polymers can be used. For metal substrates, aluminum, stainless steel (SUS), titanium, silicon, and the like can be used.

[0013] In the photoelectric conversion element 1 according to this embodiment, light is incident from the substrate 10 side, so a material with high light transmittance (for example, transparent) is used for the substrate 10. However, in the case of an inverted structure (OPV type) where light is incident from the opposite side of the substrate 10 (the second electrode 70 side), an opaque substrate may be used for the substrate 10. The thickness of the substrate 10 is not particularly limited, as long as it has sufficient strength to support the other components.

[0014] (First Electrode 20) In this embodiment, the first electrode 20 is an electrode located on the light incident surface side of the photoelectric conversion element 1. The first electrode 20 is provided on the substrate 10. The material of the first electrode 20 is not particularly limited as long as it is conductive, but in this embodiment, since light is incident from the side of the first electrode 20, the first electrode 20 is made of a transparent or translucent conductive material.

[0015] Examples of transparent or translucent electrode materials include metals and metal oxides. Examples of metals include gold, platinum, silver, copper, aluminum, nickel, indium, tantalum, and titanium. Examples of metal oxides include indium oxide, zinc oxide, tin oxide, and their composites, such as indium-tin oxide (ITO), fluorine-doped tin oxide (FTO), antimond-doped tin oxide (ATO), niobium-doped tin oxide (NTO), aluminum-doped zinc oxide, indium-zinc oxide, and niobium-titanium oxide. Other examples include titanium oxide doped with at least one selected from the group consisting of lithium, magnesium, and fluorine; gallium oxide doped with at least one selected from the group consisting of tin and silicon; gallium nitride doped with at least one selected from the group consisting of silicon and oxygen; zinc oxide doped with at least one selected from the group consisting of boron and gallium; or composites thereof. These may be used individually or in combination of two or more. Among these, transparent conductive metal oxides with high transparency are preferred, and ITO or FTO are particularly preferred.

[0016] Furthermore, conductive nanowires can be used as transparent or translucent electrode materials. Conductive nanowires are wire-like structures with a cross-sectional diameter of less than 1 μm and an average aspect ratio (long axis length / diameter) of 10 or more. The average diameter of conductive nanowires is preferably 5 nm to 250 nm, more preferably 10 nm to 150 nm, and even more preferably 10 nm to 40 nm. By setting the average diameter of conductive nanowires to 250 nm or less, the transparency of the first electrode 20 can be improved. Also, by setting the average diameter of conductive nanowires to 5 nm or more, the conductivity of the conductive nanowires can be increased, and the durability of the coating film can be improved. The average long axis length of conductive nanowires is preferably 0.5 μm to 500 μm, and more preferably 2.5 μm to 100 μm. Conductivity is exhibited when conductive nanowires come into contact with each other and a three-dimensional conductive network structure is widely distributed in space. Therefore, it is preferable that the long axis length of conductive nanowires be 0.5 μm or more. Furthermore, in order to prevent entanglement between conductive nanowires and improve the storage stability of the conductive nanowires, it is preferable that the long axis length of the conductive nanowires be 500 μm or less.

[0017] Examples of materials for conductive nanowires include metal-coated organic or inorganic fibers, conductive metal oxide fibers, metal nanowires, carbon fibers, and carbon nanotubes. Among these, metal nanowires are preferred because they satisfy the requirements for conductivity. There are no particular restrictions on the metal composition of metal nanowires, and they can be appropriately selected depending on the purpose. For example, they can be composed of one or more metals, including noble and base metal elements. However, it is preferable to include at least one metal belonging to the group consisting of noble metals (e.g., gold, platinum, silver, palladium, rhodium, iridium, ruthenium, osmium, etc.), iron, nickel, cobalt, copper, and tin, and it is even more preferable to include silver nanowires containing silver from the viewpoint of conductivity. In particular, silver nanowires have high conductivity and, because they do not completely cover the entire surface, they have high light transmittance and are also more resistant to bending than materials such as ITO.

[0018] There are no particular restrictions on the structure of conductive nanowires, and they can be appropriately selected depending on the purpose. Furthermore, known conductive nanowires can be used, and when manufacturing them, those obtained by known manufacturing methods can be used. For example, if the conductive nanowire is a silver nanowire, it can be manufactured by a method that includes reacting a silver compound in a polyol at 25°C to 180°C, using polyvinylpyrrolidone or an N-substituted acrylamide-containing polymer as a wire growth control agent.

[0019] Furthermore, the visible light transmittance of the first electrode 20 is preferably 50% to 90%, and more preferably 60% to 80%. When the visible light transmittance is 50% to 90%, durability can be improved while suppressing electrical resistance. Furthermore, when the visible light transmittance is 60% to 80%, light durability can be further improved.

[0020] The thickness of the first electrode 20 is not particularly limited and can be appropriately selected according to the purpose, but it is preferably 1 nm to 1000 nm. If the thickness of the first electrode 20 is less than 1 nm, the conductivity will decrease and the resistance will increase, which will cause a decrease in photoelectric conversion efficiency. Also, if the thickness of the first electrode 20 is greater than 1000 nm, the flexibility will decrease. The thickness of the first electrode 20 can be, for example, 10 nm to 300 nm, 5 nm to 100 μm, or 30 nm to 10 μm. If the electrode material is ITO, it is preferably 30 nm to 300 nm. The sheet resistance is preferably low, preferably 15 Ω / □ or less. The first electrode 20 may be a single layer, or it may have a structure in which layers containing materials with different work functions are stacked. If the material of the first electrode 20 is carbon or metal, it is preferable that the average thickness of the first electrode 20 be such that light transmission can be obtained. The average thickness of the first electrode 20 can be measured, for example, using a touch-type film thickness measuring instrument (e.g., device name: Dektak XT-E, manufactured by Bruker).

[0021] (Electron Transport Layer 30) The electron transport layer 30 is placed between the first electrode 20 and the photoelectric conversion layer 50. The electron transport layer 30 is a layer for efficiently transferring electrons generated in the photoelectric conversion layer 50 to the first electrode 20, and by providing the electron transport layer 30, the photoelectric conversion rate of the photoelectric conversion element 1 can be improved. The electron transport layer 30 is characterized by containing semiconductor nanoparticles. The material of the semiconductor nanoparticles used in the electron transport layer 30 is not particularly limited as long as it has electron transport properties, but for example, an inorganic n-type semiconductor can be used. As the inorganic n-type semiconductor, oxides of metal elements, nitrides of metal elements, and perovskite-type oxides can be used. As the oxides of the above metal elements, for example, oxides of Cd, Zn, In, Pb, Mo, W, Sb, Bi, Cu, Hg, Ti, Ag, Mn, Fe, V, Sn, Zr, Sr, Ga, Si, and Cr can be used, and a specific example is TiO ２ or SnO ２ Examples include GaN as a nitride of a metallic element. An example of a perovskite-type oxide is SrTiO ３ Or CaTiO ３ Examples include alkali metal or alkaline earth metal halides, alkali metal oxides such as magnesium oxide, or silicon dioxide. Suitable halogen compounds include LiF, LiCl, LiBr, LiI, NaF, NaCl, NaBr, NaI, KF, KCl, KBr, KI, and CsF, with LiF being more preferred. Examples of alkali metal oxides include magnesium oxide, titanium oxide, molybdenum oxide, vanadium oxide, zinc oxide, nickel oxide, lithium oxide, calcium oxide, cesium oxide, and aluminum oxide. In this embodiment, the material for the electron transport layer 30 is tin oxide (SnO) with a particle size of 2 to 3 nm. ２ This will be explained using particles.

[0022] The shape of the semiconductor nanoparticles is not particularly limited, but examples include spherical, linear, tubular, branched, bundled, and sheet-shaped nanoparticles, and nanoparticles of an appropriate shape can be used. The particle size of the semiconductor nanoparticles is not particularly limited, but from the viewpoint of preventing short circuits, the electron transport layer is preferably dense, for example, the average particle size of the primary particles is preferably 0.5 nm to 100 nm, more preferably 1 nm to 50 nm, and even more preferably 1 nm to 30 nm. ２ In this case, the particle size is preferably 1 nm or more and 10 nm or less, and the semiconductor nanoparticles are TiO ２ In this case, the particle size is preferably between 2 nm and 25 nm.

[0023] The thickness of the electron transport layer 30 is not particularly limited, but it is preferably 5 nm to 300 nm. If the electron transport layer 30 is too thin, the hole blocking effect will decrease, causing the generated excitons to deactivate before they can dissociate into electrons and holes, making it impossible to efficiently extract current. Conversely, if the electron transport layer 30 is too thick, the film resistance will increase, limiting the generated current and thus reducing the photoconversion efficiency.

[0024] Furthermore, in this embodiment, the electron transport layer 30 is characterized by containing a binder made of an aqueous-dispersible resin. The aqueous-dispersible resin is a resin that can be dispersed in an aqueous medium such as water, and is not particularly limited as long as it can be dispersed in an aqueous medium, but examples include resins that have been made aqueous by introducing an acid structure such as a carboxyl group by modifying with an unsaturated carboxylic acid component, or resins that have been made aqueous by introducing an acid structure such as a carboxyl group by modifying with a saturated carboxylic acid component. Specifically, examples include polyolefin resins containing an acid structure, urethane resins containing an acid structure, acrylic resins containing an acid structure, styrene-based resins containing an acid structure, polyester resins containing an acid structure, and epoxy resins having an acid structure, and two or more of these may be used in combination. Among these, from the viewpoint of suppressing the deterioration of the first electrode 20 and the electron transport layer 30 by the perovskite solution, polyolefin resins containing an acid structure, urethane resins containing an acid structure, and acrylic resins containing an acid structure are preferred.

[0025] The polyolefin resin containing an acidic structure is preferably a polyolefin resin obtained by copolymerizing an olefin component with an unsaturated carboxylic acid component. Examples of olefin components include alkenes having 2 to 6 carbon atoms, such as ethylene, propylene, isobutylene, 2-butene, 1-butene, 1-pentene, and 1-hexene, and two or more of these monomers may be used. Examples of unsaturated carboxylic acid components include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, crotonic acid, as well as half-esters and half-amides of unsaturated dicarboxylic acids.

[0026] Examples of polyolefin resins containing an acid structure include ethylene-ethyl acrylate-(anhydride) maleic acid copolymer, ethylene-butyl acrylate-(anhydride) maleic acid copolymer, ethylene-(meth)acrylic acid ester-(anhydride) maleic acid copolymer, ethylene-propylene-(meth)acrylic acid ester-(anhydride) maleic acid copolymer, ethylene-butene-(meth)acrylic acid ester-(anhydride) maleic acid copolymer, propylene-butene-(meth)acrylic acid ester-(anhydride) maleic acid copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-anhydride maleic acid copolymer, ethylene-propylene-(anhydride) maleic acid copolymer, ethylene-butene-(anhydride) maleic acid copolymer, propylene-butene-(anhydride) maleic acid copolymer, and ethylene-propylene-butene-(anhydride) maleic acid copolymer.

[0027] The urethane resin containing an acidic structure is preferably a polyurethane resin obtained by reacting a component containing an average of two or more active hydrogens per molecule with a polyvalent isocyanate component, or a polyurethane resin obtained by urethane-forming an isocyanate group-containing prepolymer by reacting a component containing an average of two or more active hydrogens per molecule with a polyvalent isocyanate component in an organic solvent with high affinity for water under conditions of excess isocyanate groups, and then neutralizing and chain-extending the prepolymer.

[0028] Components containing an average of two or more active hydrogen atoms per molecule include diol compounds such as ethylene glycol and propylene glycol, polyether diols, polyester diols, polyether ester diols, and polycarbonate diols, and two or more of these may be used. Polyvalent isocyanate components include aliphatic, alicyclic, or aromatic compounds containing an average of two or more isocyanate groups per molecule. Aliphatic diisocyanate compounds with 1 to 12 carbon atoms are preferred, such as hexamethylene diisocyanate and 2,2,4-trimethylhexane diisocyanate. Alicyclic diisocyanate compounds with 4 to 18 carbon atoms are preferred, such as 1,4-cyclohexane diisocyanate and methylcyclohexylene diisocyanate. Examples of aromatic isocyanates include tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate.

[0029] The method for introducing an acid structure into the urethane resin can be any conventional method without particular limitations. However, the acid structure may also be introduced by pre-introducing carboxyl groups into polyether diols, polyester diols, polyether ester diols, etc., by replacing some or all of the glycol component with dimethylolalkanoic acid. Examples of dimethylolalkanoic acid include dimethylolacetic acid, dimethylolpropionic acid, and dimethylolbutyric acid.

[0030] The acrylic resin containing the acid structure is preferably an acrylic resin obtained by emulsion polymerization of an ethylenically unsaturated monomer containing a (meth)acrylic monomer, or a core-shell type acrylic resin in which a copolymer of an ethylenically unsaturated monomer containing a hydrophilic (meth)acrylic monomer exists as a shell layer, and a copolymer of an ethylenically unsaturated monomer containing a hydrophobic (meth)acrylic monomer exists as a core layer.

[0031] As the ethylenically unsaturated monomer, conventionally known materials can be used and are not particularly limited, but for example, carboxyl group-containing monomers such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, acrylic anhydride, methacrylic anhydride, maleic anhydride, itaconic anhydride, fumaric anhydride, (meth)acrylic acid ester monomers such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, benzyl (meth)acrylate, aromatic monomers such as styrene, vinyltoluene, α-methylstyrene, hydroxyl group-containing monomers such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, polyethylene glycol (meth)acrylate, (meth) Examples include alicyclic alkyl group-containing monomers such as cyclopentyl acrylate, cyclohexyl (meth)acrylate, and cyclooctyl (meth)acrylate; amide group-containing monomers such as acrylamide, methacrylamide, N,N-methylenebisacrylamide, diacetone acrylamide, diacetone methacrylamide, maleamide, N-methylolacrylamide, N-methylolmethacrylamide, N-methoxymethylacrylamide, N-methoxymethylmethacrylamide, N-butoxymethylacrylamide, and N-butoxymethylmethacrylamide; and epoxy group-containing monomers such as glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, methyl glycidyl acrylate, and methyl glycidyl methacrylate.

[0032] Water-dispersible resins are preferably resins in which at least some of the acid structure is neutralized by a volatile alkaline component. Water-dispersible resins have hydrophilic functional groups (acid structures) such as carboxyl groups and sulfo groups introduced into the resin to enable dispersion in an aqueous medium, but by neutralizing this acid structure with an alkaline component, stable dispersion in an aqueous medium becomes possible, such as ammonia (NH₄). ３A neutralization process is carried out using alkaline components such as ) or potassium hydroxide (KOH) as a neutralizing agent. The inventors conducted tests to elucidate and resolve the cause of the deterioration of the first electrode 20 and electron transport layer 30 by the perovskite solution, and found that a water-dispersible resin neutralized with a volatile alkaline component is excellent in suppressing the deterioration of the first electrode 20 and electron transport layer 30 by the perovskite solution.

[0033] Therefore, it is preferable that the aqueous dispersion resin used in this embodiment uses a volatile alkaline component as a neutralizing agent, that is, a resin in which no alkaline component remains in the aqueous dispersion resin when it is formed into the electron transport layer 30. In other words, it is preferable that the electron transport layer 30 in this embodiment has no or only a small amount of alkaline component remaining after neutralizing the aqueous dispersion resin. If the alkaline component used to neutralize the aqueous dispersion resin remains in the electron transport layer 30, a hydrophilic portion of the aqueous dispersion resin will be formed in the electron transport layer 30, and this hydrophilic portion will be easily eroded by the perovskite solution. It is presumed that when this hydrophilic portion dissolves, the perovskite solution will be able to pass through the electron transport layer 30 more easily. In contrast, in this embodiment, by using a water-dispersible resin neutralized with a volatile alkaline component, the formation of hydrophilic areas in the electron transport layer 30 can be suppressed. As a result, erosion of the electron transport layer 30 by the perovskite solution can be suppressed, and it is considered that the deterioration of the first electrode 20 due to the perovskite solution passing through the electron transport layer 30 and coming into contact with the first electrode 20 can be effectively prevented.

[0034] As for the volatile alkaline component, from the viewpoint of being an alkaline component that does not remain in the electron transport layer 30, it is preferable that its boiling point is 250°C or lower, more preferably 200°C or lower, even more preferably 100°C or lower, and particularly preferably 50°C or lower. The volatile alkaline component is not particularly limited, but examples include ammonia, triethylamine, and N,N-diethylaminoethanol. Examples of non-volatile alkalis used for neutralizing the water-dispersible resin include potassium hydroxide and sodium hydroxide.

[0035] The average primary particle size of the water-dispersible resin is not particularly limited, but in its dispersed state in an aqueous medium, it is, for example, 1 nm to 200 nm. From the viewpoint of preventing short circuits, the electron transport layer is preferably dense, preferably 5 nm to 150 nm, more preferably 10 nm to 100 nm, and even more preferably 20 nm to 70 nm.

[0036] The content of the water-dispersible resin in the electron transport layer 30 is not particularly limited, but from the viewpoint of suppressing the degradation of the first electrode 20 and the electron transport layer 30 by the perovskite solution and ensuring high current and voltage as a photoelectric conversion element, it is preferably 1% to 50% by weight, more preferably 5% to 35% by weight, and even more preferably 10% to 20% by weight, relative to the content of semiconductor fine particles in the electron transport layer 30 (100% by weight of semiconductor fine particles).

[0037] (Porous layer 40) The porous layer 40 is placed between the electron transport layer 30 and the photoelectric conversion layer 50. The presence of the porous layer 40 makes it easier to form the photoelectric conversion layer 50. In addition, the material of the photoelectric conversion layer 50 penetrates into the voids of the porous layer 40, and the porous layer 40 acts as a scaffold for the photoelectric conversion layer 50, so the material of the photoelectric conversion layer 50 is less likely to be repelled or aggregated on the surface of the porous layer 40, and the photoelectric conversion layer 50 can be easily formed as a uniform film. Furthermore, it is expected that the porous layer 40 will cause light scattering, which will increase the optical path length of the light passing through the photoelectric conversion layer 50. When the optical path length increases, it is expected that the amount of electrons and holes generated in the photoelectric conversion layer 50 will increase.

[0038] The porous layer 40 includes a porous body having a plurality of voids. The porous body is formed, for example, by a series of insulating or semiconductor particles. Examples of insulating particles include aluminum oxide particles or silicon oxide particles. Examples of semiconductor particles include inorganic semiconductor particles. Examples of inorganic semiconductors include metal oxides, perovskite oxides of metal elements, metal sulfides, or metal chalcogenides. Examples of the above metal oxides are oxides of Cd, Zn, In, Pb, Mo, W, Sb, Bi, Cu, Hg, Ti, Ag, Mn, Fe, V, Sn, Zr, Sr, Ga, Si, or Cr. A more specific example of a metal oxide is TiO2. Examples of perovskite oxides of metal elements are SrTiO3 or CaTiO3. Examples of metal sulfides include CdS, ZnS, In2S3, PbS, MoS2, WS2, Sb2S3, Bi2S3, ZnCdS2, or Cu2S. Examples of metal chalcogenides include CdSe, In2Se3, WSe2, HgS, PbSe, or CdTe.

[0039] The thickness of the porous layer 40 may be 0.01 μm or more and 10 μm or less, or 0.05 μm or more and 1 μm or less. The surface roughness of the porous layer 40 may be 10 or more, or 100 or more, given by the surface roughness coefficient given by effective area / projected area. Projected area is the area of ​​the shadow cast behind an object when it is illuminated with light from directly in front. Effective area is the actual surface area of ​​the object. The effective area can be calculated from the volume obtained from the projected area and thickness of the object, and from the specific surface area and bulk density of the materials constituting the object. Specific surface area is measured, for example, by the nitrogen adsorption method.

[0040] The voids in the porous layer 40 are connected from the portion in contact with the photoelectric conversion layer 50 to the portion in contact with the electron transport layer 30. In other words, the voids in the porous layer 40 are connected from one main surface to the other main surface of the porous layer 40. As a result, the material of the photoelectric conversion layer 50 can fill the voids in the porous layer 40 and reach the surface of the electron transport layer 30. Therefore, even with the porous layer 40, electrons can be exchanged between the photoelectric conversion layer 50 and the electron transport layer 30 because they are in direct contact.

[0041] (Photoelectric conversion layer 50) The photoelectric conversion layer 50 is a layer that performs photoelectric conversion by absorbing light and moving excited electrons, and contains a perovskite compound having a perovskite structure as a material. The perovskite compound is represented by, for example, the following formula (1). ABX ３ ...(1) In the above formula (1), A is a monovalent cation, B is a divalent cation, and X is a monovalent anion.

[0042] Specifically, the monovalent cation A is a monovalent metal element cation and / or a monovalent organic cation, and more specifically, a monovalent alkali metal cation and / or a monovalent amine compound cation. As the above monovalent alkali metal cation, Cs ＋ , Rb ＋ , K ＋ etc. are exemplified. Also, as the above monovalent amine compound cation, (CH ３ NH ３ ), ((C ｘ H ２ｘ＋１ ), ｎ NH ３ ), ((CH ３ NH ３ ), ((RNH ３ ), ((C ｎ H ２ｎ＋１ NH ３ ), ((CF ３ NH ３ ), ((CF ３ NH ３ ), ((C ｘ F ２ｘ＋１ ), ((CF ３ NH ３ ), ((C ｘ F ２ｘ＋１ ), ((C ｎ F ２ｎ＋１ NH ３ ), or (CF​​​​​​​​​​​​​​​​​​​​​​​​​​２ (n is an integer of 1 or more, x is an integer of 1 or more), specifically, CH ３ NH ３ ＋ 、C ２ H ５ NH ３ ＋ 、C ３ H ７ NH ３ ＋ 、C ４ H ９ NH ３ ＋ 、CH ６ N ３ ＋ 、HC(NH ２ ) ２ ＋ 、C(NH ２ ) ３ ＋ etc. are exemplified.

[0043] Also, the divalent cation B is a divalent cation of a metal element, Pb ２＋ 、Sn ２＋ 、Ge ２＋ 、Ga ２＋ 、In ２＋ 、Al ２＋ 、Sb ２＋ 、Bi ２＋ 、Po ２＋ 、Eu ２＋ 、Yb ２＋ 、Ca ２＋ or Sr ２＋ are exemplified, and it is preferably at least one selected from Pb ２＋ 、Sn ２＋ 、and Ge ２＋ . Further, the monovalent anion X is a monovalent anion of a halogen element, and it is preferably at least one selected from F － 、Cl － 、Br － 、and I － . Also, the monovalent anion X may contain a molecular anion, and examples of the molecular anion include BF ４ － 、PF ６ － etc.

[0044] In this embodiment, a perovskite compound having the perovskite crystal structure described in (1) above is used, but the perovskite compound is not limited to the perovskite compound having the crystal structure described in (1) above. That is, perovskite crystal structures can be divided into four types, from 0-dimensional structures to 3-dimensional structures, for example, A ２ BX ４ ABX ４ Or A ｎ－１ B ｎ X ３ｎ＋１ A two-dimensional perovskite compound having a composition represented by the structure (where n is an integer between 2 and 6) can also be used. In the perovskite compound of the above structure, A, B, and X can be the same substances. The ratio of each ion constituting the perovskite compound of formula (1) does not need to be exactly the same as the ratio in formula (1) to exhibit photoelectric conversion function. When the ratio of A site ions is 1, the ratio of B site ions should be approximately 0.5 to 1.2, and the ratio of X site ions should be approximately 2.0 to 3.4.

[0045] Furthermore, the photoelectric conversion layer 50 only needs to contain a perovskite compound and may contain defects or impurities. In addition, the perovskite compound may further contain perovskite compounds with different structures, such as Ruddlesden-Popper type perovskite compounds, in addition to the perovskite compound with the above-mentioned crystalline structure. Furthermore, the thickness of the photoelectric conversion layer 50 is not particularly limited and can be, for example, 50 nm to 2 μm, or 100 nm to 1000 nm.

[0046] Perovskite compounds with a high degree of crystallinity have high electron mobility and improved photoelectric conversion efficiency. Therefore, in the photoelectric conversion layer 50 according to this embodiment, the degree of crystallinity of the perovskite compound is preferably 50% or higher, more preferably 70% or higher, and even more preferably 80% or higher. This is because a crystallinity of 50% or higher increases electron mobility and improves photoelectric conversion efficiency. The degree of crystallinity of the perovskite compound can be determined by fitting the scattering peaks originating from the crystalline portion and the halos originating from the amorphous portion detected by X-ray scattering intensity distribution measurement, calculating the integral of each intensity, and then calculating the ratio of the crystalline portion to the whole.

[0047] (Hole Transport Layer 60) The hole transport layer 60 is positioned between the photoelectric conversion layer 50 and the second electrode 70. It accepts holes from the photoelectric conversion layer 50 and also has the function of preventing the recombination of electrons and holes that are simultaneously generated in the photoelectric conversion layer 50. The material of the hole transport layer 60 is not particularly limited as long as it has hole transport properties. For example, an organic semiconductor or an inorganic semiconductor can be used, and an organic semiconductor is preferably used. An organic semiconductor forms a good interface with the photoelectric conversion layer 50, which can suppress an increase in interface defects at the time of bonding, and as a result, the photoelectric conversion efficiency and durability of the photoelectric conversion element 1 can be improved.

[0048] Furthermore, it is even more preferable to use a p-type organic semiconductor as the material for the hole transport layer 60. Examples of substances included in the p-type organic semiconductor include polythiophene derivatives; fluorene derivatives such as 2,2'-7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-MeO-TAD); carbazole derivatives such as polyvinylcarbazole; triphenylamine derivatives such as poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine](PTAA); diphenylamine derivatives; polysilane derivatives; polyaniline derivatives; polypyrrole and its derivatives; and other organic compounds. In particular, among the p-type organic semiconductors, it is preferable to use polythiophene and its derivatives, which are conductive polymers having π-conjugation. Polythiophene and its derivatives have excellent stereoregularity and relatively high solubility in solvents. Polythiophenes and their derivatives are not particularly limited as long as they are compounds having a thiophene skeleton. Specific examples of polythiophenes and their derivatives include poly(3,4-ethylene-dioxythiophene), polystyrene sulfonate (PEDOT:PSS), poly(3-hexylthiophene) (P3HT), poly(3-octylthiophene) (P3OT), poly3-methylthiophene, poly3-butylthiophene, poly3-decylthiophene, poly3-dodecylthiophene, poly3-phenylthiophene, poly3-(p-alkylphenylthiophene), poly3-butylisothionaphthene, poly3-hexylisothionaphthene, poly3-octylisothionaphthene, and poly3-decylisothionaphthene. Furthermore, as the material for the hole transport layer 60, organic semiconductors comprising triallylamine, phenylbenzidine, phenylenevinylene, tetrathiafulvalene, vinylnaphthalene, vinylcarbazole, aniline, triptycene, fluorene, azulene, pyrene, pentacene, perylene, acridine, etc., can also be used.

[0049] Furthermore, a p-type inorganic semiconductor can also be used as the material for the hole transport layer 60. Examples of substances included in the p-type inorganic semiconductor include copper oxide (for example, Cu) ２O), nickel oxide, molybdenum oxide, copper gallium oxide, copper aluminum oxide, molybdenum selenide, molybdenum selenide sulfide, copper iodide (CuI), vanadium pentoxide (V ２ O ５ Examples include carbon materials such as graphene oxide. The p-type inorganic semiconductor in the hole transport layer 60 may be used alone or in combination of two or more types. Metal oxides can also be used as the material for the hole transport layer 60. Examples of such metal oxides include copper oxide, manganese oxide, titanium oxide, molybdenum oxide, vanadium oxide, zinc oxide, nickel oxide, lithium oxide, calcium oxide, cesium oxide, and aluminum oxide.

[0050] The hole transport layer 60 is preferably substantially composed of the above-mentioned organic compound or inorganic compound, and preferably is the above-mentioned organic compound or inorganic compound itself. Furthermore, the content of the above-mentioned organic compound or inorganic compound in the hole transport layer 60 is preferably 80% by weight or more and 100% by weight or less, 90% by weight or more and 100% by weight or less, 95% by weight or more and 100% by weight or less, or 99% by weight or more and 100% by weight or less, relative to the total amount of the hole transport layer 60.

[0051] The hole transport layer 60 may include multiple layers made of different materials. For example, multiple layers may be stacked such that the ionization potential of the hole transport layer 60 decreases sequentially with respect to the ionization potential of the photoelectric conversion layer 50. This can improve the hole transport characteristics.

[0052] The thickness of the hole transport layer 60 is not particularly limited and can be, for example, 1 nm or more and 1000 nm or less. If the hole transport layer 60 is thinner than 1 nm, voltage drops are more likely to occur due to deposition defects, and if the hole transport layer 60 is thicker than 1000 nm, the electrical resistance increases and the conversion efficiency is more likely to decrease. The thickness of the hole transport layer 60 can also be 2 nm to 300 nm, 10 nm to 100 nm, 15 nm to 80 nm, 20 nm to 60 nm, etc. By having the thickness of the hole transport layer 60 within the above range, it is possible to efficiently extract holes generated in the photoelectric conversion layer 50 from the photoelectric conversion layer 50, prevent recombination of electrons and holes generated simultaneously in the photoelectric conversion layer 50, and make it easier to lighten and make the photoelectric conversion element 1 more flexible.

[0053] (Second Electrode 70) The second electrode 70 is formed on the hole transport layer 60. In this embodiment, the second electrode 70 can be formed using a transparent or translucent conductive material as exemplified in the first electrode 20. The second electrode 70 may also be configured to include conductive nanowires such as silver nanowires.

[0054] Furthermore, when the second electrode 70 is formed by applying an ink composition containing conductive nanowires, the second electrode 70 is laminated on the hole transport layer 60. Therefore, if the ink composition containing conductive nanowires contains a good solvent for the perovskite compound, such as water, the good solvent for the perovskite compound may pass through the hole transport layer 60 and act on the perovskite compound forming the photoelectric conversion layer 50, potentially degrading the photoelectric conversion layer 50. For this reason, it is preferable to use a solvent in the ink composition containing conductive nanowires that can disperse the conductive nanowires without reacting with the perovskite compound. Specifically, it is preferable to use a solvent that contains a poor solvent for perovskite as the solvent for such an ink composition. A poor solvent for perovskite compounds is a solvent in which the perovskite crystals do not substantially dissolve. Examples of poor solvents for perovskite compounds include aromatic hydrocarbons such as toluene and benzene; substituted aromatic hydrocarbons such as chlorobenzene, orthodichlorobenzene (o-dichlorobenzene), and nitrobenzene; ethers such as diethyl ether, diisopropyl ether, and cyclopentyl methyl ether (CPME); alcohols such as 1-hexanol and octanol; long-chain hydrocarbons (especially C4-10 hydrocarbons) such as hexane, heptane, octane, and dodecane; esters such as γ-butyrolactone; halogenated solvents such as dichloromethane and chloroform; fluorinated solvents such as chlorofluorocarbons, hydrochlorofluorocarbons, and hydrofluorocarbons; pyridine; and nitriles such as acetonitrile and 3-methoxypropionitrile.

[0055] (Wiring layer 80) The wiring layer 80 is a layer that forms wiring for outputting electrons extracted from the first electrode 20 to the outside and for introducing electrons into the second electrode 70, and is arranged in contact with the first electrode 20 and the second electrode 70, respectively. The wiring layer 80 is not limited to any conductive material, but for example, copper tape can be used.

[0056] (Manufacturing Method) Next, an example of a method for manufacturing the photoelectric conversion element 1 according to this embodiment will be described based on Figures 2 and 3. Figure 2 is a flowchart showing the method for manufacturing the photoelectric conversion element 1 according to this embodiment, and Figure 3 is a diagram for explaining the method for manufacturing the photoelectric conversion element 1 according to this embodiment.

[0057] In step S101, a film-like substrate 10 is prepared as shown in Figure 3(A). In this embodiment, for example, polyethylene terephthalate film (PET film) is used as the substrate 10.

[0058] In step S102, as shown in Figure 3(B), the first electrode 20 is formed on the substrate 10. Specifically, the first electrode 20 containing conductive nanowires is formed by coating or printing an ink composition containing conductive nanowires onto the substrate 10 and then drying it. The first electrode 20 may also contain residues remaining after the ink composition has been dried.

[0059] Furthermore, the ink composition containing conductive nanowires used in step S102 preferably contains a solvent capable of dispersing the conductive nanowires in order to enable uniform application of the conductive nanowires. For example, if the conductive nanowires are silver nanowires, such solvents may include water, alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methylpropanol, and 1,1-dimethylethanol, glycols such as ethylene glycol, propylene glycol, 1,3-butanediol, and diethylene glycol, and glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, propylene glycol monomethyl ether, 3-methoxy-1-butanol, and 3-methoxy-3-methyl-1-butanol.

[0060] Furthermore, an ink composition containing conductive nanowires can be prepared by appropriately selecting stirring, mixing, heating, cooling, dissolving, and dispersing the above-mentioned components using known methods. The prepared ink composition can be applied by coating methods such as spin coating, slit die coating, dip coating, bar coating, roll coating, and spray coating, or by printing methods such as screen printing, gravure printing, flexographic printing, offset printing, gravure-offset printing, and inkjet printing. In addition, to adjust the thickness of the first electrode 20, the coating material can be applied multiple times using the above-mentioned coating and printing methods to form the first electrode 20.

[0061] The content of conductive nanowires in the ink composition for forming the first electrode 20 is not particularly limited, but is preferably 0.01% to 30% by weight, more preferably 0.05% to 10% by weight, and even more preferably 0.1% to 2% by weight, relative to the total weight of the ink composition. By limiting the conductive nanowire content to 30% by weight or less, entanglement of conductive nanowires can be prevented, improving the storage stability of the conductive nanowires. Furthermore, if the conductive nanowire content is low, conductivity can be imparted to the coating film coated with the silver nanowire composition by performing multiple coatings, but from the viewpoint of productivity, it is preferable that the conductive nanowire content be 0.01% by weight or more. In addition, the ink composition for forming the first electrode 20 can be used in combination with other components as long as it does not impair its properties. Examples of other components include surfactants, surface modifiers, corrosion inhibitors, pH adjusters, binder resins, thickeners, and conductive additives.

[0062] In step S103, as shown in Figure 3(C), an electron transport layer 30 is formed on the first electrode 20. Specifically, an ink composition containing semiconductor fine particles and a water-dispersible resin is applied or printed onto the first electrode 20 and then dried to form the electron transport layer 30 containing semiconductor fine particles and a water-dispersible resin.

[0063] Furthermore, the ink composition containing semiconductor fine particles and a water-dispersible resin used in step S103 preferably contains a solvent capable of dispersing the semiconductor fine particles and the water-dispersible resin in order to enable uniform application. The solvent is not particularly limited, but for example, water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methylpropanol, 1,1-dimethylethanol, and other alcohols can be used.

[0064] Furthermore, an ink composition containing semiconductor fine particles and a water-dispersible resin can be prepared by appropriately selecting stirring, mixing, heating, cooling, dissolving, and dispersing the above-mentioned components using known methods. The prepared ink composition can be applied by coating methods such as spin coating, slit die coating, dip coating, bar coating, roll coating, and spray coating, or by printing methods such as screen printing, gravure printing, flexographic printing, offset printing, gravure-offset printing, and inkjet printing. In addition, to adjust the thickness of the electron transport layer 30, the coating material can be applied in multiple layers using the above-mentioned coating and printing methods.

[0065] The content of semiconductor fine particles and water-dispersible resin in the ink composition for forming the electron transport layer 30 is not particularly limited, but is preferably 0.1% to 30% by weight, preferably 0.5% to 20% by weight, and more preferably 1% to 15% by weight, based on the total weight of the ink composition. In addition, other components can be used in combination with the ink composition for forming the electron transport layer 30, as long as their properties are not impaired.

[0066] In step S104, as shown in Figure 3(D), a porous layer 40 is formed on the electron transport layer 30. In this embodiment, the porous layer is m-TiO ２ A layer is formed. The porous layer 40 is formed by a coating method such as spin coating. Alternatively, the photoelectric conversion element 1 can be configured without the porous layer 40.

[0067] In step S105, as shown in Figure 3(E), a photoelectric conversion layer 50 is formed on the porous layer 40. The photoelectric conversion layer 50 is formed by coating a perovskite solution containing a perovskite precursor onto the porous layer 40 using coating methods such as spin coating, slit die coating, bar coating, spray coating, dip coating, and roll coating, or printing methods such as screen printing, gravure printing, flexographic printing, offset printing, gravure offset printing, and inkjet printing, and then heating and drying it. For example, a DMF (N,N-dimethylformamide) solution containing methylammonium iodide and lead iodide can be coated by spin coating, dried, and then annealed at 90°C for 3 hours to form the photoelectric conversion layer 50. Alternatively, the photoelectric conversion layer 50 can also be formed by coating a solution in which metal halides, alkylamine halides, cesium halides, etc. are dissolved or dispersed, and then drying it. Furthermore, the photoelectric conversion layer 50 can also be formed by a two-step precipitation method in which a solution of metal halide dissolved or dispersed is applied, dried, and then immersed in a solution of alkylamine halide dissolved in it to form a perovskite compound. In addition, the photoelectric conversion layer 50 can also be formed by applying a solution of metal halide and alkylamine halide dissolved or dispersed in it, while adding a poor solvent (solvent with low solubility) for the perovskite compound to precipitate crystals.

[0068] Furthermore, when forming the photoelectric conversion layer 50, a perovskite compound having a perovskite crystal structure can be formed by dissolving a perovskite precursor in a good solvent for the perovskite compound to prepare a solution, applying this solution, and then removing (drying) a portion of the good solvent to precipitate the perovskite crystals. Examples of good solvents for the perovskite compound include N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), and acetone.

[0069] In the photoelectric conversion layer 50, it is preferable to coat a perovskite solution containing a perovskite precursor onto the porous layer 40, dry it, and then increase the crystallinity of the perovskite compound by annealing (heat treatment), irradiation with high-intensity light such as a laser, or plasma treatment. By increasing the crystallinity of the perovskite compound, the electron mobility increases, and the photoelectric conversion efficiency improves.

[0070] The annealing temperature is preferably 80°C or higher. By performing annealing at a temperature of 80°C or higher, the crystallinity of the perovskite compound can be increased, resulting in a photoelectric conversion element 1 with excellent light resistance and high photoelectric conversion efficiency. The annealing temperature is more preferably 100°C or higher, and even more preferably 120°C or higher. There is no particular upper limit to the annealing temperature, but since the effect of increasing the crystallinity does not change even at higher temperatures, and there is also an adverse effect on other components, approximately 200°C is the practical upper limit. There is no particular limit to the heating time for annealing, but it is preferably 3 minutes or more and within 3 hours. If the heating time is 3 minutes or more, the crystallinity of the perovskite compound can be sufficiently increased. If the heating time is within 3 hours, the perovskite compound can be heat-treated without thermal degradation.

[0071] In step S106, as shown in Figure 3(F), a hole transport layer 60 is formed on the photoelectric conversion layer 50. For example, the hole transport layer 60 can be formed by coating the photoelectric conversion layer 50 with a solution obtained by dissolving the material constituting the hole transport layer 60 in a solvent. The solvent may be an aqueous solvent or an organic solvent, but since it is formed on the photoelectric conversion layer 50, it is preferable to use a poor solvent for the perovskite compound contained in the photoelectric conversion layer 50. Alcohols such as ethanol or 1-hexanol can also be used. Furthermore, these solvents can be used individually or in combination. In addition, the solution for forming the hole transport layer 60 may include a supporting electrolyte and a dopant.

[0072] The hole transport layer 60 can be formed by coating, printing, or vapor deposition. Coating methods include, for example, spin coating, slit die coating, dip coating, bar coating, roll coating, and spray coating. Printing methods include, for example, screen printing, gravure printing, flexographic printing, offset printing, gravure-offset printing, and inkjet printing. If necessary, multiple materials may be mixed to form the hole transport layer 60, which may then be pressurized or fired. If the material of the hole transport layer 60 is an organic low-molecular-weight substance or an inorganic semiconductor, it is also possible to form the hole transport layer 60 by vacuum vapor deposition. Furthermore, the above methods can be used individually or in combination.

[0073] In step S107, as shown in Figure 3(G), a second electrode 70 is formed on the hole transport layer 60. In this embodiment, the second electrode 70 can be a thin silver film, and can be formed to a thickness of about 100 nm by, for example, vacuum deposition. The second electrode 70 can also be formed using an ink composition containing conductive nanowires, similar to the first electrode 20.

[0074] In step S108, as shown in Figure 3(H), the wiring layer 80 is formed. In this embodiment, copper tape is used as the wiring layer 80, and the copper tape is arranged to be connected to the first electrode 20 and the second electrode 70, respectively. This allows the power generated by the photoelectric conversion element 1 to be output to the outside via the wiring layer 80 made of copper tape.

[0075] As described above, the photoelectric conversion element 1 according to this embodiment is manufactured. In this embodiment, the procedure involves forming a first electrode 20, forming an electron transport layer 30 on the first electrode 20, and forming a photoelectric conversion layer 50 on the electron transport layer 30. However, with this procedure, there was a problem that the perovskite solution used to form the photoelectric conversion layer 50 would dissolve the electron transport layer 30 and the first electrode 20. In contrast, in this embodiment, since the electron transport layer 30 contains a binder made of a water-dispersible resin, the degradation of the electron transport layer 30 and the first electrode 20 by the perovskite solution can be suppressed, and as a result, the voltage and current of the photoelectric conversion element 1 can be increased compared to the case where the electron transport layer 30 does not contain a binder.

[0076] Next, an embodiment of the present invention will be described. In this embodiment, a first electrode 20 containing silver nanowires is formed on a substrate 10, an electron transport layer without a binder is formed on the first electrode 20, and then a photoelectric conversion layer 50 is formed on the electron transport layer. However, the silver nanowires of the first electrode 20 deteriorated due to the perovskite solution. Therefore, tests were conducted to clarify and resolve the cause of this deterioration.

[0077] (Test Example 1) Specifically, in Test Example 1, first, a first electrode 20 with a surface resistance of 15 Ω / □ was formed using an ink composition containing silver nanowires (product name: T-AG139, manufactured by Seikoh PMC Co., Ltd.). Then, DMF or NMP contained in the perovskite solution, or the perovskite solution itself, was dropped onto the electrode, and the surface resistance of the first electrode 20 was measured to verify the effect of the perovskite solution on the silver nanowires. The perovskite solution contained 142.8 mg of formamidinium iodide (FAI), cesium iodide (CsI), and 46.1 mg of lead iodide (PbI). ２ ), 27.8 mg of lead chloride (PbCl ２ This was prepared by mixing 96 μl of N-methyl-2-pyrrolidone (NMP) with 500 ml of dimethylformamide (DMF) (the same applies to Test Examples 2-5 below).

[0078] Table 1 below shows the measurement results for Test Example 1. As shown in Table 1 above, when only DMF or NMP was dropped onto the first electrode 20 made of silver nanowires, the surface resistance of the silver nanowires did not change significantly compared to when no drop was added. Therefore, it was found that DMF and NMP do not directly affect the silver nanowires. On the other hand, when a perovskite solution was dropped onto the first electrode 20 made of silver nanowires, the surface resistance of the silver nanowires exceeded 1000 Ω (also called O.L.; the same applies hereinafter). From this, it was found that when formamidinium iodide (FAI), cesium iodide (CsI), and lead iodide (PbI) were added to the first electrode 20 made of silver nanowires, the surface resistance of the silver nanowires did not change significantly. ２ ), lead chloride (PbCl ２ It is thought that perovskite precursors such as ) are acting to degrade the first electrode 20.

[0079] (Test Example 2) In Test Example 2, the effect of the perovskite solution on the electron transport layer was investigated. Specifically, an electron transport layer consisting only of tin oxide sol (primary particle size: 2 nm, product name: Ceramase S-8, manufactured by Taki Chemical Co., Ltd.) was prepared, and DMF, NMP, and the perovskite solution were dropped onto the prepared electron transport layer. The electron transport layer was then visually inspected after the dropping of DMF, NMP, and the perovskite solution. As a result, no change was observed in the electron transport layer when DMF and NMP were dropped onto the electron transport layer without a binder. On the other hand, when the perovskite solution was dropped onto the electron transport layer without a binder, it was confirmed that a part of the electron transport layer dissolved, as shown in Figure 4(A). From this, it is considered that the perovskite solution dissolves the electron transport layer and penetrates to the first electrode 20 below the electron transport layer, thereby degrading the first electrode 20.

[0080] Furthermore, in Test Example 2, an electron transport layer 30 containing a binder was prepared, similar to the laminate 2 in this embodiment. Specifically, an electron transport layer 30 was prepared containing 15% by weight of ethylene-(meth)acrylic acid copolymer (product name: Hi-Tec S-3121, manufactured by Toho Chemical Industry Co., Ltd.) in solid content relative to 100% by weight of tin oxide sol (average primary particle size: 2 nm, product name: Ceramase S-8, manufactured by Taki Chemical Co., Ltd.). Then, DMF, NMP, and perovskite solutions were dropped onto the prepared electron transport layer 30, and the electron transport layer 30 was visually inspected after the dropping of DMF, NMP, and perovskite solutions, respectively. As a result, even in the electron transport layer 30 containing a binder, no change was observed when DMF or NMP was dropped onto the electron transport layer 30. Similarly, when the perovskite solution was dropped onto the electron transport layer 30 containing the binder, no change was observed, as shown in Figure 4(B). Therefore, it is considered that adding a binder to the electron transport layer 30 can prevent the degradation of the electron transport layer 30 and the first electrode 20 by the perovskite solution.

[0081] (Test Example 3) In Test Example 3, in order to verify whether the degradation of the electron transport layer 30 and the first electrode 20 by the perovskite solution can be suppressed in the laminate 2 and photoelectric conversion element 1 according to this embodiment, the surface resistance of the laminate 2 according to this embodiment and the voltage and current of the photoelectric conversion element 1 according to this embodiment were measured. In Test Example 3, when the laminate 2 was made, a PET film was used as the substrate 10, and a first electrode 20 with the same composition containing silver nanowires and a surface resistance of 15 Ω / □ was formed on the substrate, and then an electron transport layer 30 containing a binder made of a water-dispersible resin and containing tin oxide with an average primary particle size of 2 nm at the same concentration was formed on the first electrode 20. Furthermore, when fabricating the photoelectric conversion element 1, a porous layer 40 containing titanium oxide, a photoelectric conversion layer 50 containing a perovskite compound, a hole transport layer 60 containing polystyrene sulfonate (PEDOT:PSS), and a second electrode 70 made of a silver thin film were sequentially laminated on the electron transport layer 30 of the aforementioned laminate 2 to constitute the photoelectric conversion element 1. In addition, in Test Example 3, as a comparative example, an electron transport layer without a binder was used, and the surface resistance of the laminate having the electron transport layer, and the voltage and current of the photoelectric conversion element having the laminate were measured. The measurement results in Test Example 3 are shown in Table 2 below.

[0082]

[0083] In Comparative Examples 1-4, a layer containing tin oxide but without a binder was formed as the electron transport layer. In Comparative Example 1, the thickness of the electron transport layer was 50 nm; in Comparative Example 2, it was 100 nm; in Comparative Example 3, it was 200 nm; and in Comparative Example 4, it was 300 nm. In Comparative Examples 1-4, a first electrode 20 made of silver nanowire was formed on a PET film substrate 10, and the binder-free electron transport layer from Comparative Examples 1-4 was formed on top of it to create a laminate, and the surface resistance (Ω / □) of the prepared laminate (hereinafter referred to as AgNW / electron transport) was measured. Furthermore, in Comparative Examples 1-4, a laminate (hereinafter referred to as AgNW / electron transport / PVK) was also prepared by laminating a photoelectric conversion layer 50 containing a perovskite compound on top of the electron transport layer, and the surface resistance (Ω / □) of this laminate was also measured. As a result, in Comparative Examples 1-4, surface resistances of 19-21 Ω / □ were measured for the AgNW / electron transport laminates, but the surface resistances of the AgNW / electron transport / PVK laminates were all 0.L. This is thought to be because, as shown in Test Example 1, the perovskite solution applied to form the photoelectric conversion layer 50 passed through the electron transport layer, acted on the silver nanowires, and degraded them.

[0084] Furthermore, in Comparative Examples 1-4, photoelectric conversion elements having an electron transport layer without a binder were fabricated, and the voltage and current of the fabricated photoelectric conversion elements were measured. As a result, as shown in Table 2 above, in all of the photoelectric conversion elements in Comparative Examples 1-4, the voltage and current were zero. From this, it was found that when the first electrode 20 is formed from silver nanowires and the electron transport layer is configured without a binder, the perovskite solution containing the perovskite precursor dissolves the electron transport layer and passes through the electron transport layer, degrading the silver nanowires and causing a decrease in the voltage and current of the photoelectric conversion element.

[0085] On the other hand, Examples 1-15 differ from Comparative Examples 1-4 in that the electron transport layer 30 contains a binder. Specifically, in Example 1-4, the electron transport layer 30 contains ethylene-(meth)acrylic acid copolymer (product name: Hi-Tech S-3121, manufactured by Toho Chemical Industry Co., Ltd.) as a binder for the water-dispersible resin. In addition, in Example 1-4, the electron transport layer 30 contains ethylene-(meth)acrylic acid copolymer with an average particle size of 35 nm at a concentration of 15% by weight relative to the amount of tin oxide added (100% by weight). Furthermore, in Example 1, the film thickness of the electron transport layer 30 was 50 μm, in Example 2, the film thickness of the electron transport layer 30 was 100 μm, in Example 3, the film thickness of the electron transport layer 30 was 200 μm, and in Example 4, the film thickness of the electron transport layer 30 was 300 μm.

[0086] Furthermore, in Examples 1-4, a first electrode 20 made of silver nanowires was formed on a PET film substrate 10, and an electron transport layer 30 containing the binder of Example 1-4 was formed on top of it to create a laminate 2. The surface resistance (Ω / □) of the prepared laminate 2 (hereinafter referred to as AgNW / electron transport) and the surface resistance (Ω / □) of a laminate 2 (hereinafter referred to as AgNW / electron transport / PVK) in which a photoelectric conversion layer 50 containing a perovskite compound was further laminated on top of the electron transport layer 30 were measured. As shown in Table 2 above, in Example 1-4, the surface resistance of the laminate 2 made of AgNW / electron transport was 16 to 20 Ω / □. In addition, in Example 1-4, the surface resistance of the laminate 2 made of AgNW / electron transport / PVK was 25 to 35 Ω / □, and the surface resistance did not become 0.L. as in Comparative Example 1-4. Based on these findings, by forming the photoelectric conversion layer 50 on the electron transport layer 30 containing a binder, the degradation of the silver nanowires due to the perovskite solution can be suppressed. As a result, the voltage of the photoelectric conversion element 1 becomes 0.2V or higher, and the current becomes 4.2mA or higher, achieving higher voltage and current compared to Comparative Examples 1-4.

[0087] Furthermore, in Examples 5-6, similar to Examples 1-4, an aqueous dispersion resin of ethylene-(meth)acrylic acid copolymer with an average particle size of 35 nm (product name: Hi-Tech S-3121, manufactured by Toho Chemical Industry Co., Ltd.) was used as the binder contained in the electron transport layer 30, with a content of 7.5% by weight or 30% by weight relative to the amount of tin oxide added (100% by weight). In Examples 5 and 6, compared to Examples 1-4, the surface resistance of the laminate 2 consisting of AgNW / electron transport / PVK was higher at 100 Ω / □ or 65 Ω / □, and consequently, the voltage of the photoelectric conversion element 1 was lower at 0.3 to 0.6 V and the current at 0.1 to 0.2 mA. However, in Examples 5-6 as well, the voltage and current of the photoelectric conversion element 1 were higher compared to Comparative Example 1-4, confirming that the inclusion of a binder in the electron transport layer 30 suppresses the degradation of the electron transport layer 30 and the first electrode 20. However, comparing Examples 5-6 with Examples 1-4, since Examples 1-4 yielded higher voltage and current, it is considered preferable that the binder content in the photoelectric conversion layer 50 be 10-20%.

[0088] In Examples 7-9, an aqueous dispersible resin containing an ethylene-unsaturated carboxylic acid copolymer (product name: Hi-Tech E-4A, manufactured by Toho Chemical Industry Co., Ltd.) was used as the binder contained in the electron transport layer 30. In Example 7, the binder content was 7% by weight per 100% by weight of tin oxide, in Example 8, the binder content was 15% by weight per 100% by weight of tin oxide, and in Example 9, the binder content was 30% by weight per 100% by weight of tin oxide.

[0089] In Example 7-9, the surface resistance of the laminate 2 consisting of AgNW / electron transport was 14-16 Ω / □. Furthermore, the surface resistance of the laminate 2 consisting of AgNW / electron transport / PVK was 17-20 Ω / □, and unlike Comparative Example 1-4, the surface resistance did not become 0.0. These results indicate that forming the photoelectric conversion layer 50 on the electron transport layer 30 containing the binder suppresses the degradation of the silver nanowires due to the perovskite solution. As a result, the voltage of the photoelectric conversion element 1 was 0.1-0.3 V and the current was 1.4-5 mA, achieving higher voltage and current compared to Comparative Example 1-4. Thus, it was confirmed that in the photoelectric conversion element 1 according to Example 7-9, the degradation of the silver nanowires due to the perovskite solution is suppressed, resulting in higher voltage and current in the photoelectric conversion element 1 compared to Comparative Example 1-4.

[0090] In Examples 10-11, an ethylene-(meth)acrylic acid copolymer (product name: Zychsen A, manufactured by Sumitomo Seika Co., Ltd.) was used as the binder contained in the electron transport layer 30. In Example 10, the binder content was 7.5% by weight relative to 100% by weight of tin oxide, and in Example 11, the binder content was 15% by weight relative to 100% by weight of tin oxide. In Example 10-11, the surface resistance of the laminate 2 consisting of AgNW / electron transport / PVK was 17-20 Ω / □, and when used as a photoelectric conversion element 1, the voltage was 0.29-0.31 V and the current was 0.1 mA. Thus, in the photoelectric conversion element 1 according to Example 10-11, the current value was lower compared to Example 1-9, but higher compared to Comparative Example 1-4, suggesting that the binder suppressed the degradation of the silver nanowire by the perovskite solution.

[0091] In Examples 12-13, a water-dispersible resin containing a propylene-unsaturated carboxylic acid copolymer and a polyoxyethylene alkyl (or alkenyl) ether (product name: Hi-Tech P-9018, manufactured by Toho Chemical Industry Co., Ltd.) was used as the binder contained in the electron transport layer 30. In Example 12, the binder content was 7.5% by weight per 100% by weight of tin oxide, and in Example 13, the binder content was 15% by weight per 100 parts by weight of tin oxide.

[0092] In Examples 12-13, the surface resistance of the laminate 2 consisting of AgNW / electron transport / PVK was 0.L., but the voltage of the photoelectric conversion element 1 was 0.02 to 0.33 V and the current was 0.01 to 0.2 mA, which were higher than those of Comparative Example 1-4. From this, it was found that even when acid-modified polypropylene or polyoxyethylene alkyl (or alkenyl) ether was used as the binder contained in the electron transport layer 30, the degradation of the silver nanowire by the perovskite solution could be suppressed compared to Comparative Example 1-4, which did not contain a binder.

[0093] In Examples 14-15, an ethylene-(meth)acrylic acid copolymer resin (product name: Zychsen N, manufactured by Sumitomo Seika Co., Ltd.) was used as the binder contained in the electron transport layer 30. In Example 14, the binder content was 7.5% by weight relative to 100% by weight of tin oxide, and in Example 15, the binder content was 15% by weight relative to 100% by weight of tin oxide. In Examples 14-15, the surface resistance of the laminate 2 consisting of AgNW / electron transport / PVK was 19-20 Ω / □, and when used as a photoelectric conversion element 1, the voltage was 0.02-0.1 V and the current was 0.01 mA. Thus, in the photoelectric conversion element 1 according to Example 14-15, the voltage and current were lower than in Example 1-13, but compared to Comparative Example 1-4, the voltage and current of the photoelectric conversion element 1 were higher, suggesting that the binder suppressed the degradation of the silver nanowire by the perovskite solution.

[0094] Furthermore, in this embodiment, Examples 1-11, in which at least a portion of the acidic structure of the water-dispersible resin contained in the electron transport layer 30 was neutralized by a volatile alkaline component, tended to show higher voltage and current when used as the photoelectric conversion element 1 compared to Examples 12-15, in which the structure was neutralized by a non-volatile alkaline component. Specifically, among Examples 2, 8, 11, and 15, which had the same binder content in the electron transport layer 30, Example 2, which included an ethylene-(meth)acrylic acid copolymer neutralized with a volatile alkaline component having a boiling point of 50°C or less as the binder of the electron transport layer 30, showed a voltage of 0.41V and a current of 5.1mA when used as the photoelectric conversion element 1. Example 8, which included an ethylene-unsaturated carboxylic acid copolymer neutralized with a volatile alkaline component having a boiling point of 200°C or less as the binder of the electron transport layer 30, showed a voltage of 0.27V and a current of 4.4mA when used as the photoelectric conversion element 1. Example 11, which included an ethylene-(meth)acrylic acid copolymer neutralized with a volatile alkaline component having a boiling point of 50°C or less as the binder of the electron transport layer 30, showed relatively high voltages of 0.31V and currents of 0.1mA when used as the photoelectric conversion layer 1. In contrast, Example 15, which included an ethylene-(meth)acrylic acid copolymer neutralized with a non-volatile alkaline component as the binder for the electron transport layer 30, showed a voltage of 0.02 V and a current of 0.01 mA when used as the photoelectric conversion element 1. It was found that the voltage and current tend to be higher when the photoelectric conversion element 1 contains a water-dispersible resin binder neutralized with a volatile alkaline component in the electron transport layer 30. Furthermore, in Examples 12-13, which included a propylene-unsaturated carboxylic acid copolymer neutralized with a non-volatile alkaline component in the electron transport layer 30, the surface resistance of the laminate 2 consisting of AgNW / electron transport / PVK was 0.L. This indicates that a water-dispersible resin binder neutralized with a volatile acrylic component tends to be better for suppressing the degradation of silver nanowires by the perovskite solution.

[0095] Thus, from Test Example 3, although there are differences in the degree to which the degradation of silver nanowires is suppressed depending on the type of binder contained in the electron transport layer 30, the voltage and / or current when used as a photoelectric conversion element 1 were higher in Example 1-15, which has a binder in the electron transport layer 30, compared to Comparative Examples 1-4, which do not contain a binder in the electron transport layer. Therefore, it was found that including a binder in the electron transport layer has the effect of suppressing the degradation of silver nanowires by the perovskite solution. Furthermore, it was found that using a binder in which at least some of the acid structure is neutralized by a volatile alkaline component as the binder of the water-dispersible resin contained in the electron transport layer 30 tends to result in higher voltage and current when used as a photoelectric conversion element 1 compared to using a binder neutralized by a non-volatile alkaline component.

[0096] (Test Example 4) Next, in Test Example 4, in order to verify whether the degradation of the electron transport layer 30 and the first electrode 20 by the perovskite solution can be suppressed even when a resin other than a polyolefin resin having an acidic structure is used as the binder contained in the electron transport layer, the surface resistance of the laminate 2 according to this embodiment, and the voltage, current, and surface resistance of the photoelectric conversion element 1 according to this embodiment were measured, similar to Test Example 3. The measurement results in Test Example 4 are shown in Table 3 below.

[0097]

[0098] In Example 16, a water-dispersible urethane resin (product name: Hi-Tech U-5111, manufactured by Toho Chemical Industry Co., Ltd.) was used as the binder contained in the electron transport layer 30. In Example 16, the binder content was 7.5% by weight relative to 100% by weight of tin oxide. In Example 16, when the laminate 2 consisted of AgNW / electron transport / PVK, the surface resistance was 0.L., and when it was used as the photoelectric conversion element 1, the voltage was 0.02V and the current was 0.01mA. Thus, in the photoelectric conversion element 1 according to Example 16, the voltage and current were lower compared to Examples 1-15 which used polyolefin resin, but the voltage was slightly higher compared to Comparative Example 1-4 which did not contain a binder in the electron transport layer. This suggests that the urethane resin contained in the electron transport layer 30 suppresses the degradation of the silver nanowire by the perovskite solution.

[0099] In Example 17, a self-crosslinking acrylic core-shell polymer (product name: Hyros XME-2039, manufactured by Seikoh PMC Co., Ltd.) was used as the binder contained in the electron transport layer 30. In Example 17, the binder content was 7.5% by weight relative to 100% by weight of tin oxide. In Example 17, when the laminate 2 consisted of AgNW / electron transport / PVK, the surface resistance was high at 100Ω / □, and consequently, when it was used as the photoelectric conversion element 1, the voltage was 0.2V and the current was 0.2mA. Thus, even when a self-crosslinking acrylic core-shell polymer is used as the binder contained in the electron transport layer 30, the voltage and current of the photoelectric conversion element 1 tend to be lower compared to Examples 1-15 which use a polyolefin resin. However, compared to Comparative Example 1-4 which does not contain a binder in the electron transport layer 30, the voltage and current of the photoelectric conversion element 1 tend to be higher. This suggests that the inclusion of a binder in the electron transport layer 30 suppresses the degradation of the electron transport layer 30 and the first electrode 20 by the perovskite solution.

[0100] (Test Example 5) In addition, in Test Example 5, in order to verify whether the degradation of the electron transport layer 30 and the first electrode 20 by the perovskite solution can be suppressed even when the first electrode 20 is an ITO transparent electrode with a surface resistance of 15 Ω / □, the surface resistance of the laminate 2 according to this embodiment, and the voltage, current, and surface resistance of the photoelectric conversion element 1 according to this embodiment were measured, similar to Test Examples 3 and 4. Specifically, in Test Example 5, a photoelectric conversion element was constructed by sequentially laminating a PET film as the substrate 10, an ITO transparent electrode as the first electrode 20, an electron transport layer containing tin oxide, a porous layer 40 containing titanium oxide, a photoelectric conversion layer 50 containing a perovskite compound, a hole transport layer 60 containing polystyrene sulfonate (PEDOT: PSS), and a second electrode 70 made of a silver thin film. Furthermore, in Test Example 5, in Comparative Example 5, the electron transport layer was configured without a binder, and in Example 18, the electron transport layer 30 was configured to contain ethylene-(meth)acrylic acid copolymer (product name: Hi-Tech S-3121, manufactured by Toho Chemical Industry Co., Ltd.) as a binder for the water-dispersible resin. In addition, in Comparative Example 5 and Example 18, the film thickness of the electron transport layer 30 was 200 μm. The surface resistance of the laminates of Comparative Example 5 and Example 18 was measured, and the voltage and current of the photoelectric conversion element having the laminate were measured. The measurement results for Test Example 5 are shown in Table 4 below.

[0101]

[0102] As shown in Table 4 above, in the photoelectric conversion element of Comparative Example 5, although the electron transport layer does not contain a binder, the voltage was 0.08 V and the current was 1.8 mA, which are higher voltages and currents compared to the case in Test Example 3 where silver nanowires were used for the first electrode 20. On the other hand, in the photoelectric conversion element 1 of Example 18, the voltage was 0.28 V and the current was 8.1 mA. From this, it was found that when the first electrode 20 is an ITO transparent electrode, the degree of degradation by the perovskite solution is smaller compared to when silver nanowires are used, but by including a binder in the electron transport layer 30, the degradation of the first electrode 20 and the electron transport layer 30 can be suppressed. Furthermore, in the case of ITO transparent electrodes, it is possible that the electron transport layer 30 dissolves due to the perovskite solution, causing a short circuit between the ITO transparent electrode and the photoelectric conversion layer 50, resulting in a decrease in voltage and current. Therefore, it is also possible that adding a water-dispersible resin binder to the electron transport layer 30 prevents the short circuit and allows for the acquisition of high voltage and current.

[0103] As described above, in the laminate 2 and the photoelectric conversion element 1 having the laminate 2 according to this embodiment, the electron transport layer 30 contains a water-dispersible resin, which effectively suppresses the dissolution and degradation of the electron transport layer 30 and the first electrode 20 by the perovskite solution applied when manufacturing the photoelectric conversion layer 50. As a result, the degradation of the entire photoelectric conversion element 1 is suppressed, and the voltage and / or current of the photoelectric conversion element 1 can be increased. In particular, in this embodiment, when the first electrode 20 contains conductive nanowires such as silver nanowires, the degradation of the first electrode 20 can be suppressed more effectively, and the feasibility of manufacturing the photoelectric conversion element 1 by roll-to-roll can be improved. That is, when manufacturing the photoelectric conversion element 1 by roll-to-roll, it is desirable to form the first electrode 20 by applying or printing an ink composition containing conductive nanowires such as silver nanowires. However, when the first electrode 20 is configured to include silver nanowires, the silver nanowires are degraded by the perovskite solution applied to the first electrode 20. In this embodiment, however, since the electron transport layer 30 contains a binder, the degradation of the first electrode 20 by the perovskite solution can be suppressed, making it possible to use conductive nanowires such as silver nanowires for the first electrode 20.

[0104] Furthermore, in this embodiment, the water-dispersible resin used as a binder is not particularly limited, but it is preferably a polyolefin resin. This is because, even with water-dispersible resins, some may dissolve partially in the perovskite solution, and experiments have confirmed that polyolefin resins tend to be less soluble in the perovskite solution. Moreover, in this embodiment, by using a binder in which at least a portion of the acidic structure of the electron transport layer 30 is neutralized by a volatile alkaline component, the degradation of the electron transport layer 30 and the first electrode 20 by the perovskite solution can be further suppressed, and the voltage and current when used as a photoelectric conversion element 1 can be increased.

[0105] Although preferred embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the embodiments described above. Various modifications and improvements can be made to the above embodiments, and such modified or improved forms are also included in the technical scope of the present invention.

[0106] 1...Photoelectric conversion element 2...Laminate 10...Substrate 20...First electrode 30...Electron transport layer 40...Porous layer 50...Photoelectric conversion layer 60...Hole transport layer 70...Second electrode 80...Wiring layer

Claims

1. A laminate for forming a photoelectric element by stacking photoelectric conversion layers containing a perovskite compound having a perovskite crystal structure, comprising: a substrate; electrodes stacked on the substrate; and an electron transport layer stacked on the electrodes, wherein the electron transport layer contains semiconductor nanoparticles and an aqueous dispersion resin.

2. The laminate according to claim 1, wherein the aqueous dispersion resin is a polyolefin resin.

3. The laminate according to claim 1, wherein the aqueous dispersion resin is a resin in which at least a portion of the acid structure is neutralized by a volatile alkaline component.

4. The laminate according to claim 1, wherein the content of the water-dispersible resin is 5 to 35% by weight relative to the content of the semiconductor fine particles.

5. The laminate according to claim 1, wherein the electrode is a layer containing conductive nanowires.

6. A photoelectric conversion element having a laminate according to any one of claims 1 to 5.

7. A method for manufacturing a laminate for forming a photoelectric element by stacking photoelectric conversion layers containing a perovskite compound having a perovskite crystal structure, wherein the laminate comprises a substrate, an electrode stacked on the substrate, and an electron transport layer stacked on the electrode, and the method comprises a step of forming the electron transport layer on the electrode, wherein the electron transport layer is formed using an ink composition containing semiconductor fine particles and an aqueous dispersion resin.

8. A method for manufacturing a photoelectric element, comprising forming a photoelectric conversion layer containing a perovskite compound having a perovskite crystal structure on the electron transport layer of a laminate manufactured by the method for manufacturing a laminate according to claim 7, using a solution containing a perovskite precursor.

Images