Method for manufacturing photoelectric conversion element

Abstract

To provide a method for manufacturing a photoelectric conversion element improved in adhesion between a charge transport layer and a photoelectric conversion layer.SOLUTION: Provided is a method for manufacturing a photoelectric conversion element having a first electrode, a second electrode, and a photoelectric conversion layer arranged between the first electrode and the second electrode and including a crystal of a perovskite structure. The method includes: in this order, a step of performing passivation processing on a surface of the photoelectric conversion layer; and a step of forming, between a layer formed through the passivation processing and the first electrode, a charge transport layer including insulating resin and an annular conjugate compound in which a plurality of pyrrole rings are conjugated and bonded.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 the hole transport layer. Non-Patent Document 1 describes improving conversion efficiency by mixing copper phthalocyanine and a conductive polymer in the hole transport layer. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2018-170382 A [Non-patent literature]

[0007] [Non-Patent Document 1] Q. Hu,et al,Sol.RRL,2018,3,1800264 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 in the photoelectric conversion elements described in Patent Document 1 and Non-Patent Document 1, there is room for improvement in the adhesion between the charge transport layer and the photoelectric conversion layer. SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide a method for producing a photoelectric conversion element having improved adhesion between a charge transport layer and a photoelectric conversion layer. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides A first electrode; A second electrode; a photoelectric conversion layer including a crystal having a perovskite structure, the photoelectric conversion layer being disposed between the first electrode and the second electrode; A method for producing a photoelectric conversion element comprising: A step of performing a passivation treatment on the surface of the photoelectric conversion layer; forming a charge transport layer between the layer formed by the passivation treatment and the first electrode, the charge transport layer including a cyclic conjugated compound in which a plurality of pyrrole rings are conjugated and an insulating resin; The method for producing a photoelectric conversion element is characterized by comprising the steps of: 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 adhesion between a charge transport layer and a photoelectric conversion layer, thereby improving the properties such as the photoelectric conversion efficiency of the photoelectric conversion element produced by the method. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a layer structure in a thickness direction of a first embodiment of a photoelectric conversion element of the present invention. [Diagram 2] 1 is a perspective view showing a schematic diagram of an embodiment of a moving body including a photoelectric conversion element of the present invention; [Diagram 3] FIG. 1 is a perspective view illustrating a schematic diagram of one embodiment of a building material including a photoelectric conversion element of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] <One embodiment> One embodiment is 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 first electrode; A second electrode; a photoelectric conversion layer including a crystal having a perovskite structure, the photoelectric conversion layer being disposed between the first electrode and the second electrode; A method for producing a photoelectric conversion element comprising: A step of performing a passivation treatment on the surface of the photoelectric conversion layer; forming a charge transport layer between the layer formed by the passivation treatment and the first electrode, the charge transport layer including a cyclic conjugated compound in which a plurality of pyrrole rings are conjugated and an insulating resin; The present invention is characterized in that it includes the following in this order.

[0013] As a result of investigations, the present inventors have found that the above-mentioned manufacturing method can improve the adhesion between the charge transport layer and the photoelectric conversion layer. The reason for this is believed to be as follows. Photoelectric conversion layers made of crystals with a perovskite structure have a number of crystal defects on the crystal surface. In addition, π-conjugated molecules are often used as charge transport layers because they have high charge transport layer capabilities. The above crystal defects and π-conjugated molecules have some areas where electrons are biased against each other, and the electrostatic repulsion between them reduces adhesion, which can lead to gaps between the photoelectric conversion layer and the charge transport layer.

[0014] If voids are present, the oxygen in the voids can cause deterioration of the photoelectric conversion layer, resulting in a decrease in durability, and the high resistance of air can impede the exchange of charges, reducing the conversion efficiency of the photoelectric conversion element.

[0015] On the other hand, when a passivation treatment is performed on the crystal surface of the perovskite structure and then a charge transport layer is formed, the layer formed by the passivation treatment (hereinafter also referred to as a passivation layer) inactivates the surface crystal defects of the perovskite structure, thereby eliminating electrostatic repulsion. At the same time, by forming a charge transport layer containing a cyclic conjugated compound in which multiple pyrrole rings are covalently bonded and an insulating resin, it is possible to expect the effects of suppressing peeling and improving conversion efficiency. As a result, it is believed that the gap between the photoelectric conversion layer and the charge transport layer is reduced, resulting in a photoelectric conversion element with high adhesion and improved power generation efficiency.

[0016] <Step of forming a first electrode and step of forming a second electrode> The method for manufacturing a photoelectric conversion element of the present invention preferably includes a step of forming a first electrode and a step of forming a second electrode. In the step of forming the first electrode and the step of forming the second electrode, an appropriate method can be selected according to the material of the first electrode and the material of the second electrode, respectively. Examples of such methods include, but are not limited to, a sputtering method, a vacuum deposition method, a CVD method (vapor phase growth method), and a SPD method (spray pyrolysis deposition method). The materials of the first electrode and the second electrode are as described below. 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.

[0017] When manufacturing solar cells, cutting is generally performed between each process to form circuits. Examples of cutting include mechanical patterning and laser patterning.

[0018] <Modularization process> The method for producing a photoelectric conversion element of the present invention may include a modularization step of sealing the element having the electrodes. Examples of the sealing method include sealing with a resin or sealing with a film having a resin. Examples of materials used for sealing include silazane, silicone rubber, a resin having a siloxane skeleton, a resin having fluorine, 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.

[0019] <Step of forming photoelectric conversion layer> The method for producing a photoelectric conversion element of the present invention preferably includes a step of forming a photoelectric conversion layer containing a crystal of a perovskite structure between a first electrode and a second electrode. The step of forming the photoelectric conversion layer includes a step of applying a liquid containing the material of the photoelectric conversion layer described above. Examples of the application method include spin coating, blade coating, slit die coating, screen printing, bar coater, casting, printing 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.

[0020] 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, 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 current density.

[0021] <Passivation process> The method for producing a photoelectric conversion element of the present invention includes a step of performing a passivation treatment on the surface of the photoelectric conversion layer on the side of the first electrode. The passivation process may be included in the process of forming the photoelectric conversion layer described above, or a separate passivation process may be provided after the process of forming the photoelectric conversion layer described above.

[0022] The passivation process includes a process of applying a liquid containing a material for passivation process described later. 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.

[0023] (Passivation treatment material) In the passivation process of the present invention, the materials to be subjected to the multiple passivation processes preferably contain a compound having at least one group selected from the group consisting of a hydroxy group, a carbonyl group, a carboxy group, an ester group (ester bond, -CO-O- or -O-CO-), an amino group, an ammonium salt, an ether group (ether bond, -O-), a phosphine oxide group, and a thiol group, from the viewpoint of high interaction ability with surface defects of the perovskite crystal and the charge transport material, and more preferably contain a compound having at least one group selected from the group consisting of an ester group (ester bond, -CO-O- or -O-CO-) and an ammonium salt. In the present invention, the molecular weight of the above compound is preferably 250 or less, from the viewpoint of being able to interact with microscopic surface defects of the perovskite crystal.

[0024] The material for passivation treatment in the present invention is not particularly limited, but specific examples are shown in the following formulae (A-1) to (A-47). [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka]

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[0025] Among these, the compound represented by the above formula (A-5), the compound represented by the above formula (A-6), the compound represented by the above formula (A-10), the compound represented by the above formula (A-20), the compound represented by the above formula (A-28), the compound represented by the above formula (A-31), the compound represented by the above formula (A-35), the compound represented by the above formula (A-38), the compound represented by the above formula (A-39), the compound represented by the above formula (A-42), the compound represented by the above formula (A-45), the compound represented by the above formula (A-46), and the compound represented by the above formula (A-47) are desirable in terms of ease of interaction with crystal defects on the surface of the photoelectric conversion layer.

[0026] In the above formulas (A-1) to (A-41), X - Examples of the anion include, but are not limited to, a fluorine ion, a chlorine ion, a bromine ion, an iodine ion, a cyanide ion, a nitrate ion, a benzenesulfonate ion, a p-toluenesulfonate ion, a methylsulfate ion, an ethylsulfate ion, a propylsulfate ion, a tetrafluoroborate ion, a tetraphenylborate ion, a benzenesulfinate ion, an acetate ion, a trifluoroacetate ion, a propionacetate ion, a benzoate ion, an oxalate ion, a succinate ion, a malonate ion, an oleate ion, a stearate ion, a citrate ion, a picolinate ion, a monohydrogen diphosphate ion, a dihydrogen diphosphate ion, a pentafluoropropionate ion, a chlorosulfonate ion, a fluorosulfonate ion, a perchlorate anion, a trifluoromethanesulfonyl anion, a bis(trifluoromethanesulfonyl)imide anion, a naphthalenesulfonyl ion, a naphthalene disulfonate ion, a tristrifluoromethanesulfonylmethide anion, a tetraarylborate anion, and a sulfate anion. X - As the anion, a bromide ion or an iodide ion is particularly preferred from the viewpoint of ease of maintaining the perovskite crystal structure.

[0027] In the present invention, it is preferable that the material to be subjected to the passivation treatment contains at least one compound selected from the group consisting of a compound represented by the following formula (A-38-I), a compound represented by the following formula (A-20-I), and a compound represented by the following formula (A-5-Br). [ka] [ka] [ka]

[0028] <Step of forming charge transport layer> The method for producing a photoelectric conversion element of the present invention includes a step of forming a charge transport layer between a layer formed by a passivation treatment (passivation layer) and the first electrode, the charge transport layer including a cyclic conjugated compound in which a plurality of pyrrole rings are conjugated and an insulating resin.

[0029] The step of forming the charge transport layer is preferably a method of applying a resin solution in which an insulating resin is dissolved, which allows the insulating resin to preferentially infiltrate into the gaps between the perovskite crystal grains.

[0030] Examples of the step of forming the charge transport layer include the following: a method of disposing a cyclic conjugated compound formed by conjugating a plurality of pyrrole rings on the surface of the passivation layer, and then applying a resin solution in which an insulating resin is dissolved, or a method of disposing a cyclic conjugated compound formed by conjugating a plurality of pyrrole rings on the surface of the passivation layer, and then applying a resin solution in which an insulating resin is dissolved, and then applying a solution in which a cyclic conjugated compound formed by conjugating a plurality of pyrrole rings is dispersed in a resin solution in which an insulating resin is dissolved, on the surface of the passivation layer.

[0031] (Cyclic conjugated compounds formed by conjugating pyrrole rings) The cyclic conjugated compound formed by covalently bonding a plurality of pyrrole rings used in the present invention is preferably a porphyrin compound or a phthalocyanine compound, more preferably a phthalocyanine compound, from the viewpoint of the spread of the π electron cloud that is the starting point of the interaction. The phthalocyanine compound may have a central element, and examples of the central element include Ga, Cu, Ti, Zn, Si, V, Pb, and Pt. Among them, Ga is preferred from the viewpoint of electronic interaction with insulating resins and passivation materials, and the cyclic conjugated compound is more preferably a gallium phthalocyanine compound, and particularly preferably a hydroxygallium phthalocyanine compound from the viewpoint of interaction with passivation materials.

[0032] Specific examples of the porphyrin compound of the present invention are shown in the following formula (P-1) and formula (P-2). [ka] [ka]

[0033] In the above formula (P-1) and the above formula (P-2), R1 to R 12 represents an aromatic group which may have a substituent, or an organic group which may have a substituent, and R1 to R 12 may be different from each other.

[0034] R1~R 12 Specifically, X is preferably a hydrogen atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an octyloxy group, an octabutoxy group, a halogen atom, a phenyl group, a phenoxy group, a carboxyphenyl group, a benzenesulfonic acid group, a hydroxyphenyl group, a dihydroxyphenyl group, a trihydroxyphenyl group, a methoxyphenyl group, a dimethoxyphenyl group, a trimethoxyphenyl group, a methylphenyl group, a dimethylphenyl group, a trimethylphenyl group, a pyridyl group, an aminophenyl group, a tetrasodium sulfonate group, a 4-cumylphenoxy group, a sulfonic acid group, a phenylthio group, or a tert-butyl group. In the above formula (P-1) and the above formula (P-2), X represents a metal element or an organic element, specifically, SiCl2, Cu, Zn, Pd, Pb, Ni, Pt, Co, MnCl, FeCl, VO, or RuCO is preferable.

[0035] Specific examples of the phthalocyanine compound of the present invention are shown in the following formulae (P-3), (P-4), and (P-5). [ka] [ka] [ka]

[0036] In the above formula (P-3) and the above formula (P-4), R 13 ~R 28 represents an aromatic group which may have a substituent or an organic group which may have a substituent, and R 13 ~R 28 may be different from each other. Specifically, hydrogen, a methyl group, an ethyl group, a propyl group, a isopropyl group, a butyl group, an octyloxy group, an octabutoxy group, a halogen atom, a phenyl group, a phenoxy group, a carboxyphenyl group, a benzenesulfonic acid group, a hydroxyphenyl group, a dihydroxyphenyl group, a trihydroxyphenyl group, a methoxyphenyl group, a dimethoxyphenyl group, a trimethoxyphenyl group, a methylphenyl group, a dimethylphenyl group, a trimethylphenyl group, a pyridyl group, an aminophenyl group, a tetrasodium sulfonate base, a 4-cumylphenoxy group, a sulfonic acid group, a phenylthio group, and a tert-butyl group are preferred. In the above formulas (P-3), (P-4), and (P-5), X represents a metal element or an organic element, and specifically, SiCl 2、 Cu, Zn, Pd, Pb, Ni, Pt, Co, MnCl, FeCl, VO, RuCO are preferred.

[0037] (Insulating resin) Specific examples of insulating resins include polyacetal resins, acrylic resins, polyarylate resins, polycarbonate resins, polyvinyl acetate resins, polyester resins, polyamide resins, polyurethane resins, and polystyrene resins.

[0038] In the present invention, the glass transition temperature of the insulating resin is preferably 95° C. or less. Within this range, it is easy to come into close contact with the charge transport material (a cyclic conjugated compound formed by conjugating pyrrole rings), and a more effective charge distribution can be formed. The glass transition temperature can be determined by a differential scanning calorimeter (DSC).

[0039] In the present invention, the insulating resin is preferably a polyvinyl acetal resin or a polyvinyl butyral resin, which is easily in close contact with the charge transport material (a cyclic conjugated compound formed by conjugating pyrrole rings) and can form a more effective charge distribution.

[0040] In the present invention, the photoelectric conversion element 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.

[0041] 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. 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.

[0042] 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 a layer can be performed, for example, by performing TOF-SIMS / FE-TEM / EDS line analysis measurement of a cross section of a photoelectric conversion element to confirm the element distribution of a specific element. Analysis of each layer may be performed by peeling and removing the completed photoelectric conversion element to expose the layer to be analyzed. In the present invention, the volume ratio is quantified by using the area ratio of the exposed surface or cross section as the volume ratio of the layer.

[0043] In the method for producing a photoelectric conversion element of the present invention, the photoelectric conversion element has a first electrode, a second electrode, and a photoelectric conversion layer containing a crystal of a perovskite structure disposed between the first electrode and the second electrode. FIG. 1 is a cross-sectional view showing a schematic configuration of one embodiment of the photoelectric conversion element of the present invention. The photoelectric conversion element 1 has a second electrode 3, an electron transport layer 4, a photoelectric conversion layer 5, a passivation layer 6, a charge transport layer 7, and a first electrode 8 on a substrate 2. One of the first electrode 8 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 8 and the second electrode 3 with an external circuit.

[0044] 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 the first electrode 8, the charge transport layer 7, and the passivation layer 6, and generates electrons or holes. That is, the photoelectric conversion layer 5 generates a current between the first electrode 8 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 8), and may not be formed in some cases. A form in which a plurality of electron transport layers 4 and photoelectric conversion layers 5 are laminated may be used. Such a form may also be called a tandem structure. Each member will be described below. In addition, a photoelectric conversion element may be fabricated on the substrate 2 in the order of the first electrode 8, the charge transport layer 7, the passivation layer 6, the photoelectric conversion layer 5, the electron transport layer 4, and the second electrode 3.

[0045] [Photoelectric conversion element] The present invention relates to a method for producing a photoelectric conversion element, and the photoelectric conversion element of the present invention is characterized by having a first electrode, a second electrode, a photoelectric conversion layer containing a crystal of a perovskite structure disposed between the first electrode and the second electrode, and a charge transport layer between the photoelectric conversion layer and the first electrode. In addition, in order to improve the photoelectric conversion efficiency, the photoelectric conversion elements 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 include a perovskite solar cell using a perovskite crystal in the photoelectric conversion layer, a silicon solar cell, a CIGS solar cell, and the like.

[0046] The photoelectric conversion layer of the photoelectric conversion element of the present invention and each layer including the charge transport layer can be formed by coating or vapor deposition. Examples of the coating method 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 the 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 layer will be described below.

[0047] 〔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 8 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.

[0048] 〔electrode〕 The photoelectric conversion element of the present invention has a first electrode and a second electrode. The materials of the first electrode 8 and the second electrode 3 are not particularly limited, and conventionally known materials can be used. For example, 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 can be mentioned.

[0049] 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.

[0050] At least one of the first electrode 8 and the second electrode 3 on the light incident side is a transparent electrode, and the other may be a transparent electrode or may also serve as a reflective layer formed 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 8 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 electrodes may be patterned electrodes.

[0051] [Photoelectric Conversion Layer] The photoelectric conversion element of the present invention has a photoelectric conversion layer including a crystal having a perovskite structure, which is disposed between a first electrode and a second electrode. 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]

[0052] 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. As A in the above general formula [1], for example, in the case of an organic molecule, C p N m H n (wherein p, m, and n are all positive integers) are preferred. Specific examples include methylammonium and formamidium.

[0053] 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.

[0054] When the constituent A cations are too large to fit within the 3D perovskite crystal, they form 2D perovskite crystals, 2.5D perovskite crystals that have both 2D and 3D properties, bilayer crystals of 3D and 2D perovskite structures, or mixed 3D and 2D perovskite crystals, all of which can function as a photovoltaic layer.

[0055] A bilayer crystal of 3D and 2D perovskite is a crystal in which 3D and 2D perovskite structure crystals are stacked as independent, separate layers, while a mixed 3D / 2D perovskite is a crystal with a structure that combines regions or domains of both 2D or 2.5D layered and 3D perovskite structure crystals.

[0056] The crystals having a two-dimensional perovskite or 2.5-dimensional perovskite structure are 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]

[0057] In the above general formulas, the general formula [2] forms an RP (Ruddlesden-Popper) type perovskite structure, the general formula [3] forms a DJ (Dion-Jacobson) type perovskite structure, and the general formula [4] forms an ACI (Alternating cations in the interlayer) type perovskite structure.

[0058] R', R'', and R''' in the above general formulas [2] to [4] are organic molecules or metal cations which may have a substituent, and specific examples thereof include 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, guanidinium, propylammonium, propargylamine, alkylammonium, cyclohexylmethylammonium, 4-(aminomethyl)piperidinium, piperidinium, pyrrolidinium, cyclohexylmethylammonium, 4-(aminomethyl)piperidinium, piperidinium, pyrrolidinium, cyclohexylmethylammonium, 4-aminomethyl)piperidin ... Cylammonium, 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.

[0059] 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.

[0060] 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.

[0061] Specifically, 3D perovskites, 2D perovskites, and mixed 3D / 2D perovskites 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) 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)2MA2Pb3I<h2 style=";text-align:left;direction:ltr"> 10, (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 in 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, for example, as shown in Table 1. 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 perovskite crystals.

[0062] [Table 1]

[0063] 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.

[0064] The crystal with the perovskite structure 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 the presence of such a structure makes it easy to change the orientation of the octahedron in the crystal lattice, thereby increasing the mobility of electrons in the crystal with the perovskite structure and improving the photoelectric conversion efficiency of the photoelectric conversion element.

[0065] 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.

[0066] 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. 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.

[0067] In the present invention, the surface roughness Ra of the perovskite crystal of the photoelectric conversion layer is preferably 10 nm or more and 200 nm or less. When the surface roughness Ra is 10 nm or more, the recombination suppression effect of the insulating resin is more likely to be exhibited. When the surface roughness Ra is larger than 200 nm, the charge transporting particles are more likely to penetrate to the second electrode side of the photoelectric conversion layer, and the recombination suppression effect may be reduced.

[0068] [Passivation layer] In the photoelectric conversion element of the present invention, a passivation layer is formed on the surface of the photoelectric conversion layer on the first electrode side. The passivation layer contains a passivation material. In the photoelectric conversion element of the present invention, it is preferable that the passivation material is disposed between the crystals of the perovskite structure of the photoelectric conversion layer. Each item of the passivation material is as described above.

[0069] [Charge transport layer] The photoelectric conversion element of the present invention has a charge transport layer disposed between the photoelectric conversion layer and the first electrode, and the charge transport layer is formed of a cyclic conjugated compound in which pyrrole rings are conjugated on the surface of the passivation layer, and an insulating resin. It is preferable that the photoelectric conversion element of the present invention completely covers the photoelectric conversion layer and the passivation layer. The items such as the cyclic conjugated compound in which pyrrole rings are conjugated and the insulating resin are as described above.

[0070] In the present invention, the charge transport layer contains a cyclic conjugated compound formed by conjugating pyrrole rings, and an insulating resin, and the volume of the cyclic conjugated compound formed by conjugating pyrrole rings in the charge transport layer is preferably 5 to 30 times the volume of the insulating resin in the charge transport layer. 8 In the present invention, during charge transport, the mass content of the cyclic conjugated compound formed by conjugating the pyrrole rings is preferably 5 to 30 times the mass content of the insulating resin.

[0071] The thickness of the charge transport layer is preferably from 1 nm to 1000 nm, more preferably from 5 nm to 500 nm, and particularly preferably from 10 nm to 200 nm.

[0072] The charge transport layer can be formed by preparing a coating solution for the charge transport layer containing the above-mentioned materials and solvent, forming this coating film on the passivation layer, and drying it. Examples of the solvent used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Among these solvents, alcohol-based solvents or aromatic hydrocarbon-based solvents are preferred.

[0073] [Second Charge Transport Layer] In the present invention, from the viewpoint of film compatibility of the charge transport layer 7, a second charge transport layer may be further provided between the charge transport layer 7 and the first electrode 8.

[0074] 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.

[0075] 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.

[0076] [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.

[0077] 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.

[0078] 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 of the electron transport layer 4 is 1 nm or more, holes can be blocked sufficiently, and if it is 2000 nm or less, it is unlikely to become a resistance during electron transport, and the photoelectric conversion efficiency is high. The thickness is more preferably 3 nm at the lower limit and 1000 nm at the upper limit, and even more preferably 5 nm at the lower limit and 500 nm at the upper limit.

[0079] <Application Examples> Application examples of the present invention include photoelectric conversion devices, moving objects, and building materials. [Photoelectric conversion device] The photoelectric conversion device of the present invention has 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. The photoelectric conversion element may be stacked with photoelectric conversion elements having different absorption wavelengths in order to increase the output voltage.

[0080] 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.

[0081] [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 equipped with the photoelectric conversion element of the present invention. The moving body 30 has the photoelectric conversion element 31 of the present invention and a vehicle 32 equipped with the photoelectric conversion element 31. The photoelectric conversion element 31 is arranged at a position where the vehicle 32 can receive external light. If the moving body 30 is an automobile, it may be arranged on the roof. The electric energy obtained by the photoelectric conversion element 31 may be used as the power of the moving body 30 or as the power of 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.

[0082] 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.

[0083] [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.

[0084] 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.

[0085] 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.

[0086] In addition to the above application examples, the following application examples can be mentioned. Examples of portable devices include calculators, sensors, and small solar panels. Examples of wearable devices include glasses-type terminals, wristwatch-type terminals, and portable medical equipment. Examples of sheet structures supported by multiple frames include tents, vinyl greenhouses, and truck beds. Examples of structures that are used in a fixed position include 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

[0087] 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 description of the examples, "parts" are by mass unless otherwise specified.

[0088] Example 1 Preparation of Charge Transport Material 1 Process (1) In a nitrogen flow atmosphere, 5.46 parts of orthophthalonitrile and 45 parts of α-chloronaphthalene were put into a reaction vessel, and then heated to a temperature of 30°C and maintained at this temperature. Next, 3.75 parts of gallium trichloride were put in at this temperature (30°C). The water concentration of the mixed liquid at the time of putting in was 150 ppm. Then, the temperature was raised to 200°C. Next, under a nitrogen flow atmosphere, the reaction was carried out at a temperature of 200°C for 4.5 hours, and then cooled. When the temperature reached 150°C, the product was filtered. The obtained filtrate was dispersed and washed using N,N-dimethylformamide at a temperature of 140°C for 2 hours, and then filtered. The obtained filtrate was washed with methanol and then dried to obtain chlorogallium phthalocyanine in a yield of 71%.

[0089] Process (2) 4.65 parts of the chlorogallium phthalocyanine was dissolved in 139.5 parts of concentrated sulfuric acid at a temperature of 10° C., and the solution was dropped into 620 parts of ice water under stirring to reprecipitate, and then 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. Next, the obtained wet cake (filtrate) was dispersed and washed with ion-exchanged water, and then filtration using a filter press was repeated three times.

[0090] Finally, freeze-drying was performed to obtain hydroxygallium phthalocyanine (hydrated hydroxygallium phthalocyanine) with a solid content of 23 mass% in a yield of 71%. This hydroxygallium phthalocyanine was dried in a Hyper Dry dryer (product name: HD-06R, frequency (oscillation frequency): 2455 MHz ± 15 MHz, manufactured by Japan Biocon) to obtain hydroxygallium phthalocyanine (OHGaPc) (crystal) with a water content of 1.0 mass% or less.

[0091] Process (3) Five parts of the hydroxygallium phthalocyanine 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 charge transport material 1 (specific gravity 1.6).

[0092] Preparation of resin solution 1 1.0 g of polyvinyl butyral (product name: BM-2, manufactured by Sekisui Chemical Co., Ltd., specific gravity 1.6) was dissolved in 19 g of 2-propanol with stirring for 24 hours to obtain resin solution 1.

[0093] <Preparation of passivation solution 1> X - A passivation solution 1 was obtained by dissolving 2.5 mg of compound (A-5) (2-phenylethylamine hydroiodide, PEAI, Tokyo Chemical Industry Co., Ltd.) using bromide ions in 1 ml of 2-propanol.

[0094] [Formation of Electron Transport Layer] A square ITO-coated glass substrate with sides of 25 mm was cleaned, and a 5-fold diluted tin oxide (2) colloidal solution (15% water dispersion, manufactured by Alfa Aesar) was spin-coated onto it, followed by heating at 150°C for 30 minutes to form a thin-film electron transport layer with a thickness of 16 nm.

[0095] [Formation of photoelectric conversion layer] 0.487 g of lead bromide, 1.034 g of formamidium iodide, 2.903 g of lead iodide, and 0.139 g of methylammonium bromide were dissolved in 4.25 g of N,N-dimethylformamide and 1.216 g of dimethyl sulfoxide, and the mixture was stirred for 1 hour (solution 1). Furthermore, 0.100 g of cesium iodide was dissolved in 0.285 g of dimethyl sulfoxide, and the mixture was stirred for 1 hour (solution 2). The dissolved cesium iodide solution (solution 2) was then added to solution 1 to prepare a photoelectric conversion layer coating solution. This coating solution was spin-coated on the electron transport layer by the poor solvent method, resulting in the formation of a photoelectric conversion layer containing Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 A photoelectric conversion layer having a thickness of 600 nm and a surface roughness Ra of 13 nm was formed from the photoelectric conversion layer 3.

[0096] [Formation of Passivation Layer] The passivation solution was spin-coated onto the photoelectric conversion layer to form a passivation layer having a thickness of 10 nm.

[0097] [Formation of Charge Transport Layer] 0.1g of the charge transport material 1 and 0.01g of the calixarene compound (JP Patent Publication 2003-207913) were mixed with 10.6g of 2-propanol, and 11g of beads (zirconia beads, Treceram (registered trademark) zirconia beads, 0.3mm) were encapsulated in this mixture, and dispersion was performed for 7 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 6 hours using a paint shaker to prepare a charge transport layer solution. This charge transport layer solution was spin-coated on the passivation layer to form a charge transport layer with a thickness of 160nm.

[0098] [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 100 nm.

[0099] [Formation of the first electrode] On the second charge transport layer, a layer having a thickness of 80 nm and an area of ​​0.09 cm 2 Gold electrodes were formed at 10 locations by vacuum deposition to obtain a photoelectric conversion element.

[0100] [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 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 on an inclined sample stage, and then using a scanning electron microscope (apparatus: Carl Zeiss, SmartSEM).

[0101] Example 2 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the passivation material of the passivation solution 1 is changed to the material described in compound (A-45).

[0102] Example 3 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the charge transport material 1 is represented by the following formula (Pc-1). [ka]

[0103] Example 4 A photoelectric conversion element is obtained in the same manner as in Example 3, except that the passivation material of the passivation solution 1 is changed to the material described in Compound (A-20).

[0104] Example 5 A photoelectric conversion element is obtained in the same manner as in Example 3, except that the passivation material of the passivation solution 1 is changed to the material described in compound (A-5). Note that X- in compound (A-5) uses a bromide ion.

[0105] Example 6 A photoelectric conversion element is obtained in the same manner as in Example 2, except that the charge transport substance 1 is represented by the following formula (Pc-1).

[0106] Example 7 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the charge transport material 1 is changed to chlorogallium phthalocyanine.

[0107] Example 8 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the passivation material of the passivation solution 1 is changed to the material described in compound (A-46).

[0108] Example 9 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the passivation material of the passivation solution 1 is changed to the material described in compound (A-35).

[0109] Example 10 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the passivation material of the passivation solution 1 is changed to the material described in Compound (A-42).

[0110] Example 11 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the passivation material of the passivation solution 1 is changed to the material described in Compound (A-6).

[0111] Example 12 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the ratio of the volume of the charge transport material 1 to the volume of the insulating resin is set to 5.

[0112] Example 13 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the charge transport material 1 is changed to copper phthalocyanine.

[0113] Example 14 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the passivation material of the passivation solution 1 is changed to the material described in Compound (A-10).

[0114] Example 15 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the passivation material of the passivation solution 1 is changed to the material described in compound (A-39). Note that X- in compound (A-39) is an iodine ion.

[0115] (Example 16) A photoelectric conversion element is obtained in the same manner as in Example 1, except that the passivation material of the passivation solution 1 is changed to the material described in compound (A-28).

[0116] (Example 17) A photoelectric conversion element is obtained in the same manner as in Example 1, except that the passivation material of the passivation solution 1 is changed to the material described in Compound (A-47).

[0117] (Example 18) A photoelectric conversion element is obtained in the same manner as in Example 1, except that the insulating resin is polymethyl methacrylate (PMMA, manufactured by Sigma-Aldrich, glass transition temperature: 100° C.).

[0118] (Example 19) A photoelectric conversion element is obtained in the same manner as in Example 2, except that the ratio of the volume of the charge transport material 1 to the volume of the insulating resin is set to 1.

[0119] (Example 20) A photoelectric conversion element is obtained in the same manner as in Example 1, except that the charge transport material 1 is tetraphenylporphyrin (TPP).

[0120] Example 21 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the ratio of the volume of the charge transport material 1 to the volume of the insulating resin is set to 30.

[0121] Example 22 A photoelectric conversion element is obtained in the same manner as in Example 1, except that the passivation material of the passivation solution 1 is changed to the material described in compound (A-31).

[0122] Example 23 A photoelectric conversion element is obtained in the same manner as in Example 2, except that the ratio of the volume of the charge transport material 1 to the volume of the insulating resin is set to 40.

[0123] Comparative Example 1 A photoelectric conversion element is obtained in the same manner as in Example 12, except that the charge transport material 1 is SPIRO-OMeTAD.

[0124] Comparative Example 2 A photoelectric conversion element is obtained in the same manner as in Example 3, except that poly(3-hexylthiophene-2,5-diyl) (P3HT) is used as the conductive resin instead of the insulating resin.

[0125] Comparative Example 3 A photoelectric conversion element is obtained in the same manner as in Example 3, except that the passivation solution is not used.

[0126] [evaluation] (Gap length) The photoelectric conversion element produced in Example 1 was cut and fixed to a sample stage, and an observation image of the cut surface was obtained using a scanning electron microscope (device: Carl Zeiss, SmartSEM). The height of the gap between the surface of the photoelectric conversion layer and the charge transport layer in the observation image was measured and used as the gap length. The gap lengths were measured at five points in the image, and the average value was used as the representative value of the gap length. The results are shown in Table 2. The direction of the gap height is perpendicular to the surface of the photoelectric conversion layer.

[0127] [Photoelectric conversion efficiency] A power supply (KEITHLEY, Model 236) was connected between the electrodes of the photoelectric conversion element prepared in Example 1, and the intensity was 114 mW / cm 2 The photoelectric conversion efficiency was measured by irradiating a certain amount of light using a solar simulator (manufactured by Yamashita Denso Co., Ltd.) and measuring the generated current and voltage. In addition, measurements were taken at 10 electrodes for each photoelectric conversion element, and the average value was used as the representative value for that photoelectric conversion element. The results are shown in Table 2.

[0128] 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 Table 2, the mass refers to the ratio of the mass of the cyclic conjugated compound to the mass of the insulating resin in the charge transport layer.

[0129] [Table 2]

[0130] The disclosure of this embodiment includes the following method. (Method 1) A first electrode; A second electrode; a photoelectric conversion layer including a crystal having a perovskite structure, the photoelectric conversion layer being disposed between the first electrode and the second electrode; A method for producing a photoelectric conversion element comprising: A step of performing a passivation treatment on the surface of the photoelectric conversion layer; forming a charge transport layer between the layer formed by the passivation treatment and the first electrode, the charge transport layer including a cyclic conjugated compound in which a plurality of pyrrole rings are conjugated and an insulating resin; A method for producing a photoelectric conversion element, comprising the steps of: (Method 2) The method for producing a photoelectric conversion element according to Method 1, wherein the insulating resin has a glass transition temperature of 95° C. or lower. (Method 3) The method for producing a photoelectric conversion element according to Method 1 or 2, wherein the mass content of the cyclic conjugated compound in the charge transport layer is 5 to 30 times the mass content of the insulating resin. (Method 4) The method for producing a photoelectric conversion element according to any one of Methods 1 to 3, wherein the cyclic conjugated compound is a phthalocyanine compound. (Method 5) 5. The method for producing a photoelectric conversion element according to any one of Methods 1 to 4, wherein the cyclic conjugated compound is a gallium phthalocyanine compound. (Method 6) 6. The method for producing a photoelectric conversion element according to any one of Methods 1 to 5, wherein the cyclic conjugated compound is a hydroxygallium phthalocyanine compound. (Method 7) 7. The method for producing a photoelectric conversion element according to any one of Methods 1 to 6, wherein in the passivation treatment step, a material for the passivation treatment contains a compound having at least one group selected from the group consisting of a hydroxyl group, a carbonyl group, a carboxyl group, an ester group, an amino group, an ammonium salt, an ether group, a phosphine oxide group, and a thiol group. (Method 8) The method for producing a photoelectric conversion element according to any one of Methods 1 to 7, wherein in the passivation treatment step, a material for the passivation treatment includes a compound having at least one group selected from the group consisting of an ester group and an ammonium salt. (Method 9) The method for producing a photoelectric conversion element according to Method 7 or 8, wherein the compound has a molecular weight of 250 or less. (Method 10) The method for producing a photoelectric conversion element according to any one of Methods 1 to 9, wherein the material for the passivation treatment contains at least one compound selected from the group consisting of a compound represented by the following formula (A-38-I), a compound represented by the following formula (A-20-I), and a compound represented by the following formula (A-5-Br). [ka] [ka] [ka] [Explanation of symbols]

[0131] 1 Photoelectric conversion element 2. Board 3 Second electrode 4 Electron transport layer 5 Photoelectric conversion layer 6 Passivation Layer 7 Charge transport layer 8 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 first electrode; A second electrode; a photoelectric conversion layer including a crystal having a perovskite structure, the photoelectric conversion layer being disposed between the first electrode and the second electrode; A method for producing a photoelectric conversion element comprising: A step of performing a passivation treatment on the surface of the photoelectric conversion layer; forming a charge transport layer between the layer formed by the passivation treatment and the first electrode, the charge transport layer including a cyclic conjugated compound in which a plurality of pyrrole rings are conjugated and an insulating resin; A method for producing a photoelectric conversion element, comprising the steps of:

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

3. The method for producing a photoelectric conversion element according to claim 1 , wherein the mass content of the cyclic conjugated compound in the charge transport layer is 5 to 30 times the mass content of the insulating resin.

4. The method for producing a photoelectric conversion element according to claim 1 , wherein the cyclic conjugated compound is a phthalocyanine compound.

5. The method for producing a photoelectric conversion element according to claim 1 , wherein the cyclic conjugated compound is a gallium phthalocyanine compound.

6. The method for producing a photoelectric conversion element according to claim 1 , wherein the cyclic conjugated compound is a hydroxygallium phthalocyanine compound.

7. 2. The method for producing a photoelectric conversion element according to claim 1, wherein in the passivation treatment step, a material for the passivation treatment includes a compound having at least one group selected from the group consisting of a hydroxyl group, a carbonyl group, a carboxyl group, an ester group, an amino group, an ammonium salt, an ether group, a phosphine oxide group, and a thiol group.

8. 2. The method for producing a photoelectric conversion element according to claim 1, wherein in the step of performing the passivation treatment, a material for the passivation treatment includes a compound having at least one group selected from the group consisting of an ester group and an ammonium salt.

9. The method for producing a photoelectric conversion element according to claim 7 or 8, wherein the compound has a molecular weight of 250 or less.

10. The method for producing a photoelectric conversion element according to claim 1, wherein the material for the passivation treatment comprises at least one compound selected from the group consisting of a compound represented by the following formula (A-38-I), a compound represented by the following formula (A-20-I), and a compound represented by the following formula (A-5-Br). 【Chemistry 1】 【Chemistry 2】 【Chemistry 3】

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