Solar cell and production method therefor

Abstract

A solar cell (1) is provided with, in order from a substrate (2), an electron transport layer (4), a porous electron transport layer (5), a spacer layer (6), and a hole transport layer (7). The porous electron transport layer (5) and the spacer layer (6) each include a perovskite compound in the pore portions therein. The spacer layer (6) has a porosity of 70% or higher.

Description

Solar cell and its manufacturing method

[0001] The present disclosure relates to a solar cell using a perovskite compound and a method for producing the same.

[0002] In recent years, solar cells have become increasingly popular as a method for utilizing renewable energy. While solar cells using inorganic photoelectric conversion elements (e.g., silicon-based solar cells, CIGS-based solar cells, and CdTe-based solar cells) are widely used, solar cells using organic photoelectric conversion elements (e.g., organic thin-film solar cells, dye-sensitized solar cells, and perovskite solar cells) are also being considered. Perovskite solar cells, in particular, have been actively researched because they can be fabricated at lower cost than conventional solar cells (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2016-178167

[0004] A conventional solar cell has a substrate, an underlayer laminated on the substrate, and a light-absorbing layer containing an organic-inorganic perovskite compound formed inside the underlayer. The underlayer is formed by spraying at least one of N-type semiconductor particles and insulating particles to which the organic-inorganic perovskite compound is attached onto the substrate.

[0005] Incidentally, perovskite compounds are known to deteriorate due to moisture, and conventional solar cells have the problem of having poor barrier properties, allowing moisture to penetrate and cause deterioration.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a solar cell that prevents the intrusion of moisture-containing air and improves reliability, and a method for manufacturing the same.

[0007] The solar cell according to the present disclosure is a solar cell comprising, in order from a substrate, an electron transport layer, a porous electron transport layer, a spacer layer, and a hole transport layer, wherein the porous electron transport layer and the spacer layer have a perovskite compound in the voids, the spacer layer has a porosity of 70% or more, and contains a decomposition product or reaction product of a perovskite material and an organic onium salt, and the organic onium salt is an iodide, bromide, or chloride, and contains a carboxylic acid.

[0008] In the solar cell according to the present disclosure, the porous electron transport layer and the spacer layer may be formed of a metal oxide selected from titanium oxide, zirconium dioxide, aluminum oxide, and silicon dioxide, either alone or in combination.

[0009] The method for manufacturing a solar cell according to the present disclosure includes the steps of providing, in order from a substrate, an electron transport layer, a porous electron transport layer, a spacer layer, and a hole transport layer, wherein the porous electron transport layer and the spacer layer have a perovskite compound in the voids, the spacer layer has a porosity of 70% or more, and contains a decomposition product or a reaction product of a perovskite material and an organic onium salt, and the organic onium salt is an iodide, bromide, or chloride, and contains a carboxylic acid.

[0010] According to the present disclosure, by increasing the porosity, a large amount of perovskite crystals is produced, improving permeability, inhibiting the intrusion of moisture-containing air, and improving reliability.

[0011] Fig. 1 is a schematic cross-sectional view showing a solar cell according to an embodiment of the present disclosure; Fig. 2 is a schematic explanatory diagram showing a structure of a perovskite compound; Fig. 3 is a characteristic diagram showing the results of comparing the characteristics of a solar cell according to an embodiment of the present disclosure and a comparative example; Fig. 4 is a cross-sectional SEM photograph of a spacer layer; and Fig. 5 is a characteristic diagram showing the results of analysis of the spacer layer.

[0012] Solar cells according to embodiments of the present disclosure will be described below with reference to the drawings.

[0013] FIG. 1 is a schematic cross-sectional view showing a solar cell according to an embodiment of the present disclosure.

[0014] A solar cell 1 according to an embodiment of the present disclosure includes a substrate 2 having a transparent electrode layer 3 formed on its surface, and an electron transport layer 4, a porous electron transport layer 5, a spacer layer 6, and a hole transport layer 7 stacked on top of the substrate 2.

[0015] The base 2 is the base of the solar cell 1 and is the same as or includes the substrate or base material. Examples of the shape of the base 2 include a flat plate and a film. When light is irradiated onto the surface of the solar cell 1 facing the base 2 (the underside of the base 2 in FIG. 1), the base 2 is preferably transparent. In this case, examples of materials for the base 2 include transparent glass and heat-resistant transparent resins. When light is irradiated from the opposite side, the base 2 may be opaque. Note that "transparent" means that light is transmitted through the base 2, but this does not exclude materials that reflect light even slightly. It is sufficient that the base 2 transmits light appropriately, and can be considered synonymous with being provided on the light-receiving surface side of the solar cell (including the portion where light is incident, as in the present disclosure). Therefore, being provided at least on the light-receiving surface side of the solar cell can be considered transparent.

[0016] The transparent electrode layer 3 is formed on the substrate 2 or on the surface of the substrate 2, and functions as an electrode for extracting photovoltaic power from the solar cell 1. The transparent electrode layer 3 is made of a transparent conductive material, such as FTO (fluorine-doped tin oxide), CuI (copper iodide), ITO (indium tin oxide), or SnO ２ Examples of conductive transparent materials include tin oxide (tin oxide), aluminum zinc oxide (AZO), indium zinc oxide (IZO), gallium zinc oxide (GZO), and antimony-doped tin oxide (ATO), as well as conductive transparent polymers. Note that the chemical formulas are representative examples and may be any compound names (same in the present disclosure). Furthermore, the composition ratios of the chemical formulas are preferably stoichiometric, but do not necessarily have to be stoichiometric (same in the present disclosure).

[0017] In this embodiment, the transparent electrode layer 3 is divided into two parts, and for the sake of explanation, one of the transparent electrode layers 3 may be referred to as the first electrode portion 3a (the right side in Figure 1) and the other as the second electrode portion 3b (the left side in Figure 1).

[0018] The electron transport layer 4 is a layer capable of transporting electrons generated in the perovskite. Naturally, it possesses this function as long as it functions as a solar cell, and can be considered synonymous with being disposed on the electron transport side of the perovskite compound of the solar cell. Therefore, as long as it is disposed at least on the electron transport side of the perovskite compound, it can be considered to have an electron transport function. The electron transport layer 4 preferably has the function of blocking the transport of holes. The electron transport layer 4 is preferably dense, with few or no pores within the layer. Furthermore, most of these pores are independent and unconnected. Therefore, even when a liquid is dropped onto the dense layer, the liquid hardly penetrates into the dense layer. For example, in a cross-sectional observation of the dense layer, the porosity relative to the layer area is 10% or less. The electron transport layer 4 is formed of titanium oxide or tin oxide. In this embodiment, the electron transport layer 4 is provided only on the first electrode portion 3a and not on the second electrode portion 3b.

[0019] The term "layer" does not specify thickness or width, and includes a pattern or island shape, or a layer having portions of different thickness. A layer is preferably a member having a substantially constant thickness.

[0020] Dense matter is also called compact, compact substance, etc., and is the same as or includes these.

[0021] The term "porous" is also referred to as "porous" or "mesoporous," and includes the same or both of these. Furthermore, "porous" refers to a material that can contain a perovskite compound in voids.

[0022] Furthermore, the term "dense material" refers to a material having extremely small voids. That is, a dense material refers to a material in which the maximum void width is less than 5 nm when observed through a cross section by SEM. Preferably, a dense material is one that suppresses the penetration of perovskite compounds, and is free of perovskite compounds on one side of the thickness direction of the dense material. More preferably, a dense material is one in which perovskite compounds cannot be contained in voids, or one that does not have a portion where the perovskite compound is continuously present throughout the thickness of the dense portion. That is, if the maximum void width cannot be confirmed as a dense material, it is sufficient that observation by SEM or EDX reveals that there are no portions where the perovskite compound is present throughout the layer thickness. In the present disclosure, unless otherwise contradictory, SEM observation can be performed to confirm the presence of a 400 nm wide cross-sectional SEM (or EDX) image. For example, when a cross section of 400 nm in width is observed by SEM or EDX, if there is no portion in which the perovskite compound exists throughout the thickness of the layer, the layer can be said to be a dense layer.

[0023] The porous electron transport layer 5 functions as an electron transport layer that transports electrons generated by photoexcitation to the electrode. Examples of materials that can be used for the porous electron transport layer 5 include titanium oxide, tin oxide, and aluminum oxide. Furthermore, an N-type inorganic oxide is suitable for the porous electron transport layer. A porous layer has numerous pores that are interconnected. When a liquid (with good wettability) is dropped onto a porous layer (with hollow pores), the liquid penetrates into the porous layer. For example, a porous layer may have a porosity of 35% or more relative to the layer volume when observed in cross section. In this embodiment, the porous electron transport layer 5, like the electron transport layer 4, is provided only on the first electrode portion 3a and not on the second electrode portion 3b. Like the electron transport layer 4, the porous electron transport layer 5 is also a layer that can transport electrons generated in the perovskite compound. Naturally, it also functions as a solar cell. That is, as long as it is disposed on the electron transport side of the perovskite compound of the solar cell, it can have the function of transporting electrons. The porous electron transport layer 5 may preferably be a mesoporous layer. Furthermore, it is even more preferable if the porous electron transport layer 5 is a mesoporous nanocrystalline layer.

[0024] The spacer layer 6 is made of a porous material, preferably an insulator. Examples of materials for the spacer layer 6 include metal oxides such as titanium oxide, zirconium dioxide, aluminum oxide, and silicon dioxide. The spacer layer 6 preferably has a porosity (porosity) of 70% or more of the entire spacer layer 6, including the voids. The spacer layer 6 preferably has a large number of voids with a size of 20 nm or more. In other words, the spacer layer 6 is made up of, for example, metal oxides 6c that constitute the spacer layer 6 itself and the voids between the metal oxides 6c. The spacer layer 6 also has voids with a size of less than 20 nm, and the porosity includes these small voids.

[0025] Furthermore, a light absorbing layer that absorbs irradiated light is provided in the gaps of the spacer layer 6. In this embodiment, the spacer layer 6, like the electron transport layer 4, has an insulating layer laminated portion 6a formed on the first electrode portion 3a and an inter-electrode portion 6b that covers the side surfaces of the electron transport layer 4 and the porous electron transport layer 5 and fills between the first electrode portion 3a and the second electrode portion 3b. In the spacer layer 6, it is preferable that the particles of the metal oxide 6c are formed so as to be continuously connected.

[0026] The hole transport layer 7 is a layer that collects holes photoexcited in the light absorption layer and is made of a carbon electrode material that forms a porous layer. The hole transport layer 7 has a collection layer laminated portion 7a that covers the insulating layer laminated portion 6a with respect to the spacer layer 6, and an electrode connecting portion 7b that covers the side surface of the inter-electrode portion 6b and is laminated on the second electrode portion 3b.

[0027] The light absorbing layer described above is a layer containing a perovskite compound. As long as a solar cell has a photoelectric conversion function, the light absorbing layer naturally generates electrons and holes upon photoexcitation. The electrons generated in the light absorbing layer move to the electron transport layer, and the holes generated in the light absorbing layer move to the hole transport layer 7, resulting in charge separation. Therefore, as long as a solar cell has a photoelectric conversion function, it can be said that electrons and holes are generated upon photoexcitation. The porous electron transport layer 5 and the hole transport layer 7 also contain layers filled with a perovskite compound. That is, the voids in the porous electron transport layer 5 and the hole transport layer 7 also contain a perovskite compound. It is desirable that the voids in the porous electron transport layer 5 and the hole transport layer 7 are filled with a perovskite compound. The thickness of the light absorbing layer is preferably 500 nm or more and 2 μm or less, and more preferably 700 nm or more and 800 nm or less.

[0028] The perovskite compound contained in the light absorbing layer has the general formula: ABX ３...(1). The composition ratio of each element is preferably 1:1:3, but is not necessarily 1:1:3. The content of each element may vary as appropriate, and each constituent element does not necessarily have to be a single type. As long as the light-absorbing layer has photoelectric conversion function, there is a degree of freedom in the configuration as described above. In general formula (1), A is an organic molecule (including an organic group or an organic cation, as defined in the present disclosure) or an inorganic atom or molecule (including an inorganic group or an inorganic cation, as defined in the present disclosure) or a combination thereof; B is a metal atom or molecule (including a metal cation, as defined in the present disclosure); and X is a halogen atom or molecule or a chalcogen atom or molecule (including a halogen anion or a chalcogen anion, as defined in the present disclosure). In general formula (1), the three Xs may be the same or different from one another. When contained in the light absorbing layer, a perovskite compound can absorb light and convert it into electricity, and this fact should also be taken into consideration. That is, a perovskite compound can be confirmed by having A, B, and X, for example, by having organic molecules, metal atoms, and halogen atoms. Furthermore, a perovskite compound can be confirmed by detecting elements corresponding to A, B, and X, as long as the light absorbing layer has a photoelectric conversion function. For example, molecules containing carbon, nitrogen, and hydrogen are suitable as organic molecules, and therefore, carbon, nitrogen, hydrogen, metal elements, and halogens or chalcogens can be detected. Alternatively, a perovskite compound can be confirmed by having A, B, and X, for example, by having inorganic atoms, metal atoms, and halogen atoms. Furthermore, a perovskite compound can be confirmed by detecting elements corresponding to A, B, and X, as long as the light absorbing layer has a photoelectric conversion function. For example, cesium or rubidium is suitable as the inorganic atom, and therefore, it is sufficient to detect cesium or rubidium, a metal element, and a halogen or chalcogen. Furthermore, since it is a natural consequence that a light absorbing layer has a crystalline structure in order to have a photoelectric conversion function, it is not necessary to confirm that the compound is a perovskite compound.The light absorbing layer may contain a compound other than a perovskite compound.

[0029] The light absorption layer may contain an organic-inorganic hybrid compound. An organic-inorganic hybrid compound refers to a compound containing an inorganic material and an organic material. Organic-inorganic hybrid compounds also include perovskite compounds, and solar cells using perovskite compounds are also called organic-inorganic hybrid solar cells. "Organic" typically refers to a material composed primarily of carbon. Note that graphite, graphene, carbon nanowires, carbon nanofibers, carbon nanotubes, and carbon materials such as carbon and carbon black that function as electrodes are not considered to be organic materials. In other words, organic refers to a material that contains carbon as one of its primary components, excluding the above-mentioned carbon materials such as graphite. "Inorganic" refers to a material that is not organic.

[0030] In general formula (1), examples of the organic molecule represented by A include alkylamine, alkylammonium, and nitrogen-containing heterocyclic compounds. In the perovskite compound (1), the organic molecule represented by A may be only one type of organic molecule, or may be two or more types of organic molecules.

[0031] Examples of alkylamines include methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, ethylmethylamine, methylpropylamine, butylmethylamine, methylpentylamine, hexylmethylamine, ethylpropylamine, and ethylbutylamine.

[0032] The alkylammonium is an ionized product of the alkylamine. Examples of the alkylammonium include methylammonium, ethylammonium, propylammonium, butylammonium, pentylammonium, hexylammonium, dimethylammonium, diethylammonium, dipropylammonium, dibutylammonium, dipentylammonium, dihexylammonium, trimethylammonium, triethylammonium, tripropylammonium, tributylammonium, tripentylammonium, trihexylammonium, ethylmethylammonium, methylpropylammonium, butylmethylammonium, methylpentylammonium, hexylmethylammonium, ethylpropylammonium, and ethylbutylammonium.

[0033] Examples of the nitrogen-containing heterocyclic compound include imidazole, azole, pyrrole, aziridine, azirine, azetidine, azeto, azole, imidazoline, and carbazole. The nitrogen-containing heterocyclic compound may be an ionized compound. As the ionized nitrogen-containing heterocyclic compound, phenethylammonium is preferred.

[0034] In general formula (1), the organic molecule represented by A is preferably methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, methylammonium, ethylammonium, propylammonium, butylammonium, pentylammonium, hexylammonium, or phenethylammonium, more preferably methylamine, ethylamine, propylamine, methylammonium, ethylammonium, or propylammonium, and even more preferably methylammonium.

[0035] In general formula (1), examples of the metal atom represented by B include lead, tin, zinc, titanium, antimony, bismuth, nickel, iron, cobalt, silver, copper, gallium, germanium, magnesium, calcium, indium, aluminum, manganese, chromium, molybdenum, and europium. In the perovskite compound, the metal atom represented by B may be only one type of metal atom, or may be two or more types of metal atoms. From the viewpoint of improving the light absorption characteristics and charge generation characteristics of the perovskite compound 7, the metal atom represented by B is preferably a lead atom or a tin atom. From the viewpoint of reducing lead, a tin atom is preferred.

[0036] In general formula (1), examples of halogen atoms represented by X include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms, and examples of chalcogen atoms include oxygen atoms, sulfur atoms, selenium atoms, and tellurium atoms. In the perovskite compound, the halogen atoms or chalcogen atoms represented by X may be one type or two or more types. As the halogen atom represented by X, an iodine atom is preferred from the viewpoint of enabling the perovskite compound to utilize light in a wide wavelength range. Specifically, of the three Xs, it is preferred that at least one X represents an iodine atom, and it is more preferred that all three Xs represent iodine atoms.

[0037] The perovskite compound may be a compound represented by the general formula "CH ３ NH ３ PbX ３ (wherein X represents a halogen atom)" is preferred, and ３ NH ３ PbI ３ As the perovskite compound, the general formula "CH ３ NH ３ PbX ３ " (particularly, compounds represented by CH ３ NH ３ PbI ３ By using the above-mentioned compound, electrons and holes can be generated more efficiently in the perovskite compound, and as a result, the photoelectric conversion efficiency of the solar cell 1 can be further improved.

[0038] The porous electron transport layer 5 and the spacer layer 6 are preferably formed of a metal oxide selected from titanium oxide, zirconium dioxide, aluminum oxide, and silicon dioxide, either alone or in combination.

[0039] Next, a process for fabricating the spacer layer 6 will be described. In this embodiment, nano-ZrO with an average particle size of 4 nm is used. ２ The particles were dispersed in a 5% aqueous solution of acetic acid to form nano-ZrO ２ Next, a sol containing ZrO particles having an average particle size of 50 nm is prepared. ２ The particles and ethyl cellulose, which is a binder, are mixed in turpineol to form ZrO ２ A slurry is prepared. Then, nano-ZrO ２ Sol and ZrO ２ The slurry is mixed with ethyl cellulose and turpineol, and the water in the mixture is removed using an evaporator to prepare a porous ceramic film-forming composition.

[0040] The porous ceramic film-forming composition thus obtained is applied, dried at 150°C for 3 minutes, and then heat-treated in air at 450°C for 1 hour to form a porous ceramic film (spacer layer 6).

[0041] The porosity of the spacer layer 6 is determined by the binder and ZrO ２ The weight ratio of the binder to ZrO can be adjusted by, for example, ２ When the weight ratio is set to 2.2, the porosity can be set to 70%, and the binder / ZrO ２ If the weight ratio is 0.20, the porosity can be set to 40%.

[0042] When fabricating the solar cell 1, first, a substrate is fabricated using a general photolithography process, screen printing process, etc., with appropriate settings made for the portions where each layer of the solar cell 1 will be provided. The fabricated substrate has a porous layer as described above, and the solar cell 1 is fabricated by dripping a perovskite precursor solution containing a perovskite compound (described below) from the top of the substrate and baking it.

[0043] Although FIG. 1 shows a configuration in which an electrode layer is provided only on the substrate 2, the present invention is not limited to this, and a configuration in which an additional electrode layer is provided on the hole transport layer 7 may also be used.

[0044] FIG. 2 is a schematic explanatory diagram showing the structure of a perovskite compound.

[0045] The spacer layer 6 described above contains a decomposition product or reaction product of a perovskite material and an organic onium salt, where the organic onium salt is an iodide, bromide, or chloride and contains a carboxylic acid. When the perovskite crystal 10a reacts with the organic onium salt containing a carboxylic acid, carboxy groups 10b containing carbon chains are generated on the surface of the perovskite crystal 10a. As shown in FIG. 2 , in the perovskite compound 10, the carboxy groups 10b with carbon chains surround the perovskite crystal 10a, thereby acting as a barrier layer and improving water durability.

[0046] A in the above general formula (1) is, for example, a methylammonium ion (MA ＋ , C.H. ３ NH ３ ), formamidium ion (FA ＋ , CH(NH ２ ) ２ ), and guanidinium ion (GA ＋ ) or an organic cation having an amino group such as Cs ＋ , Rb ＋ , Cu ＋ , Pd ＋ , Pt ＋ , Ag ＋ , Au ＋ , Rh ＋ , and Ru ＋ The perovskite compound may contain at least one of these cations.

[0047] B in the above general formula (1) is, for example, a lead ion (Pb ２＋ ) and tin ions (Sn ２＋ The metal ions may be metal ions of elements in Group 14 (Group IV-B), such as ZnO, ZnS, ZnCl, ZnO ...

[0048] X in the above general formula (1) is, for example, an iodine ion (I － ), bromine ion (Br － ), and chloride ions (Cl － The perovskite compound may contain at least one of these halide ions.

[0049] The perovskite compound is, for example, CH ３ NH ３ PbI ３ , FASnI ３ FA is CH(NH ２ ) ２ is.

[0050] In the process of producing the solar cell 1, after each layer is formed on the substrate 2, a perovskite precursor solution containing an organic onium salt is dropped onto the substrate, followed by baking to form a light absorbing layer. In this embodiment, the organic onium salt-containing perovskite precursor solution contains 100% Pb and 5% 5-aminovaleric acid hydroiodide (5-AVAI) added.

[0051] Next, the results of a comparison of the characteristics of solar cell 1 according to an embodiment of the present disclosure and a comparative example fabricated under different conditions will be described with reference to FIG.

[0052] FIG. 3 is a characteristic diagram showing the results of comparing the characteristics of the solar cell according to the embodiment of the present disclosure with those of a comparative example.

[0053] 3 shows the change in conversion efficiency retention (vertical axis) over time (horizontal axis) as a result of evaluation of solar cell 1 according to an embodiment of the present disclosure and two comparative examples (Comparative Example 1 and Comparative Example 2) fabricated under different conditions. In Fig. 3, the evaluation result of solar cell 1 according to the embodiment (first evaluation result HK1) is shown by a solid line, the evaluation result of Comparative Example 1 (second evaluation result HK2) is shown by a dashed line, and the evaluation result of Comparative Example 2 (third evaluation result HK3) is shown by a dashed line.

[0054] Comparative Example 1 differs from Solar Cell 1 according to the present embodiment in that the porosity of the spacer layer 6 is 40%. Comparative Example 2 differs from Solar Cell 1 according to the present embodiment in that 5-AVAI was not added in the fabrication process.

[0055] As shown in Figure 3, the first evaluation result HK1 shows that the conversion efficiency retention rate dropped to about 80% after about 200 hours, but the change thereafter was small, and the conversion efficiency retention rate remained high. In contrast, the second evaluation result HK2 shows that the conversion efficiency retention rate dropped to about 60% after about 200 hours, and then gradually decreased. Furthermore, the third evaluation result HK3 shows that the conversion efficiency retention rate dropped significantly over time, and after about 400 hours, the conversion efficiency retention rate was 20% or less.

[0056] As can be seen from the results shown in FIG. 3, in this embodiment, the porosity of the spacer layer 6 is set to 70% or more, so that a large amount of perovskite crystals is generated, improving permeability, inhibiting the intrusion of moisture-containing air, and improving reliability.

[0057] FIG. 4 is a SEM photograph of a cross section of the spacer layer.

[0058] 4 is an SEM photograph of a cross section of the spacer layer 6 fabricated in the same process as the solar cell 1 according to the present embodiment. ２ It can be seen that numerous perovskite crystals are generated in the voids of the metal oxide 6c. The porosity of the spacer layer 6 can be determined by taking an SEM photograph such as that shown in FIG. 4 and calculating the ratio of the metal oxide 6c to the voids.

[0059] FIG. 5 is a characteristic diagram showing the results of analyzing the spacer layer.

[0060] FIG. 5 shows a spacer layer 6 (ZrO ２) by X-ray diffraction (XRD) (first diffraction result SK1). In addition, two reference examples (second diffraction result SK2 and third diffraction result SK3) are ZrO without 5-AVAI added. ２ The analysis results for the above are also shown. In Fig. 5, the horizontal axis represents the diffraction angle (2θ / deg), and the vertical axis represents the intensity. Note that in Fig. 5, the positions of the first diffraction result SK1 to the third diffraction result SK3 on the vertical axis are shifted to prevent them from overlapping, in consideration of ease of viewing the drawing. Therefore, attention is focused on whether or not there are any locally increased intensity portions (peaks) in each of the first diffraction result SK1 to the third diffraction result SK3.

[0061] 5, the first diffraction result SK1 differs from the second diffraction result SK2 and the third diffraction result SK3 in that a first peak P1 at a diffraction angle of 5.8 degrees and a second peak P2 at a diffraction angle of 23.2 degrees are present. In this way, whether 5-AVAI is added in the production process may be analyzed using an X-ray diffraction method or the like.

[0062] It should be noted that the embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present disclosure should not be interpreted solely by the above-described embodiments, but should be defined based on the claims. Furthermore, all modifications within the scope and meaning equivalent to the claims are included.

[0063] This application claims priority based on Japanese Patent Application No. 2023-140892, filed on August 31, 2023, the contents of which are incorporated herein by reference. Furthermore, all references cited in this specification are specifically incorporated herein by reference in their entirety.

[0064] REFERENCE SIGNS LIST 1 Solar cell 2 Substrate 3 Transparent electrode layer 4 Electron transport layer 5 Porous electron transport layer 6 Spacer layer 7 Hole transport layer

Claims

1. A solar cell comprising, in order from a substrate, an electron transport layer, a porous electron transport layer, a spacer layer, and a hole transport layer, wherein the porous electron transport layer and the spacer layer have a perovskite compound in the voids, the spacer layer has a porosity of 70% or more, and has a decomposition product or reaction product of a perovskite type material and an organic onium salt, and the organic onium salt is an iodide, bromide, or chloride, and contains a carboxylic acid.

2. The solar cell according to claim 1, wherein the porous electron transport layer and the spacer layer are formed from a metal oxide selected from the group consisting of titanium oxide, zirconium dioxide, aluminum oxide, and silicon dioxide, either alone or in combination of two or more of these.

3. A method for manufacturing a solar cell, comprising the steps of providing, in order from a substrate, an electron transport layer, a porous electron transport layer, a spacer layer, and a hole transport layer, wherein the porous electron transport layer and the spacer layer have a perovskite compound in the voids, the spacer layer has a porosity of 70% or more, and has a decomposition product or reaction product of a perovskite type material and an organic onium salt, and the organic onium salt is an iodide, bromide, or chloride, and contains a carboxylic acid.

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