Photoelectric conversion element, photoelectric conversion module, and photoelectric conversion system

Abstract

A photoelectric conversion element according to the present disclosure is characterized by comprising: a conductive film (2); an electron transport layer (3) that is provided on the conductive film (2); a porous layer (4) that is provided on the electron transport layer (3) and includes a first layer (4a) and a second layer (4b) which is provided below the first layer (4a); a porous conductive layer (5) that is provided on the porous layer (4); and a perovskite compound (6) that is provided in voids of the porous layer (4). This photoelectric conversion element is also characterized in that: the first layer (4a) has a first projection part (4ap) that protrudes toward the porous conductive layer (5); and a first layer first region (S41a), which is a region in the plane direction where the first projection part (4ap) is not present, includes the central part of the first layer (4a).

Description

Photoelectric conversion element, photoelectric conversion module, and photoelectric conversion system

[0001] This disclosure relates to a photoelectric conversion element, a photoelectric conversion module, and a photoelectric conversion system. This application claims priority to Japanese Patent Application No. 2023-140803, filed on August 31, 2023, the contents of which are incorporated herein by reference.

[0002] Photoelectric conversion elements have been disclosed in the past.

[0003] For example, Patent Document 1 discloses a solar cell formed by filling a layered structure of FTO / electron transport layer 1 (e.g., dense TiO2 (c-TiO2)) / mesoporous nanocrystalline layer 2 (e.g., TiO2) / mesoporous insulating spacer 4 (e.g., porous ZrO2) / mesoporous hole collection layer 5 (e.g., mesoporous carbon) with a perovskite-type semiconductor material. The perovskite-type semiconductor material is formed by dropping a precursor solution of the material onto the layered structure and drying it.

[0004] Japanese Patent Application Laid-Open No. 2016-523453

[0005] However, since a portion of the dropped precursor solution of the perovskite compound tends to flow out of the laminated structure, there is a risk that the voids in the laminated structure may not be sufficiently filled with the perovskite compound material.

[0006] In view of the above problems, the present disclosure provides a photoelectric conversion element, a photoelectric conversion module, and a photoelectric conversion system that prevent a portion of the dropped precursor solution of a perovskite compound from flowing out of the stacked structure and have high conversion efficiency.

[0007] A photoelectric conversion element according to one aspect of the present disclosure comprises a conductive film, an electron transport layer provided on the conductive film, a porous layer provided on the electron transport layer and including a first layer and a second layer provided below the first layer, a porous conductive layer provided on the porous layer, and a perovskite compound provided in voids in the porous layer, wherein the first layer has a first convex portion protruding toward the porous conductive layer, and a first region of the first layer, which is a region in a planar direction where the first convex portion is not present, includes a central portion of the first layer.

[0008] A photoelectric conversion module according to another aspect of the present disclosure includes the photoelectric conversion element described above.

[0009] A photoelectric conversion system according to another aspect of the present disclosure includes the photoelectric conversion module described above and a control circuit.

[0010] As described above, the present disclosure makes it possible to provide a photoelectric conversion element, a photoelectric conversion module, and a photoelectric conversion system that have high conversion efficiency by preventing a portion of the dropped precursor solution of a perovskite compound from flowing out of the stacked structure.

[0011] FIG. 1 is a plan view of a photoelectric conversion module including a photoelectric conversion element according to the present disclosure. FIG. 2 is a cross-sectional view taken along II-II of the photoelectric conversion module shown in FIG. 1. FIG. 3 is a cross-sectional view taken along III-III of the photoelectric conversion element shown in FIG. 1. FIG. 4 is a first modified example of the photoelectric conversion element shown in FIG. 3. FIG. 5 is a second modified example of the photoelectric conversion element shown in FIG. 3. FIG. 6 is a third modified example of the photoelectric conversion element shown in FIG. 3. FIG. 7 is a fourth modified example of the photoelectric conversion element shown in FIG. 3. FIG. 8 is a fifth modified example of the photoelectric conversion element shown in FIG. 3. FIG. 9 is a schematic diagram of a photoelectric conversion system according to the present disclosure.

[0012] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that the present embodiments described below do not unnecessarily limit the content of the present disclosure as defined in the claims, and are not limited as long as there are no contradictions. Not all of the configurations described in the present embodiments are essential to the solution of the present disclosure. Furthermore, the light incident side (also referred to as the light receiving surface side) is expressed as the lower side (-Z direction) and the side opposite the light incident side as the upper side (+Z direction), but this is for convenience and does not relate to the installation orientation or recommended installation orientation. Furthermore, as long as there are no contradictions, the top and bottom can be reversed or replaced with left and right. In other words, the present invention is valid even if the light incident side and the side opposite the light incident side are swapped as long as there are no contradictions.

[0013] 1. Photoelectric Conversion Module Fig. 1 is a plan view of a photoelectric conversion module 100 including a photoelectric conversion element 10 according to the present disclosure. The photoelectric conversion module 100 according to the present disclosure includes a photoelectric conversion element 10 described below. The photoelectric conversion module 100 in Fig. 1 is illustrated as having six photoelectric conversion elements 10 connected in series as an example, but the number of photoelectric conversion elements 10 connected in series is not limited to this. Furthermore, the number is not limited to a series connection, and parallel connection is also possible.

[0014] 1, which shows the photoelectric conversion module 100 as viewed from above, the electron transport layer 3, the porous layer 4, and the porous conductive layer 5 provided in the photoelectric conversion element 10 are present on the surface. A barrier layer (not shown) may be provided on these layers.

[0015] The barrier layer may be made of a material with high gas barrier properties, a dense inorganic material layer, or an insulating material.

[0016] Fig. 2 is a cross-sectional view taken along line II-II of the photoelectric conversion module 100 shown in Fig. 1. As shown in Fig. 2, photoelectric conversion elements 10 are integrated in the x direction.

[0017] The photoelectric conversion element 10 comprises, from the bottom, a substrate 1, a transparent conductive film 2, an electron transport layer 3, a porous layer 4 including a first layer 4a and a second layer 4b, a porous conductive layer, and a perovskite compound 6 provided in the voids of the porous layer 4.

[0018] Another aspect of the present disclosure is a solar cell module in which photoelectric conversion elements are integrated and modularized, characterized in that the substrate 1 is a transparent substrate.

[0019] The transparent conductive film 2, the porous layer 4, and the porous conductive layer 5 are each patterned and separated for each photoelectric conversion element 10. Each layer may be patterned after layer formation (film formation) using, for example, a laser scribing method or a mechanical scribing method, or may be patterned simultaneously with layer formation (film formation) using, for example, a screen printing method or a gravure printing method. Furthermore, heat treatment may be performed when each layer is formed.

[0020] Adjacent photoelectric conversion elements 10 are connected in series in region P3 by contacting the transparent conductive film 2 and the porous conductive layer 5 via the electron transport layer 3. Note that the electron transport layer 3 may be patterned in advance so that the transparent conductive film 2 and the porous conductive layer 5 are in direct contact with each other in region P3.

[0021] After the porous layer 4 is provided, a precursor solution of the perovskite compound 6 is dropped onto the porous conductive layer 5, causing the precursor solution to penetrate into the porous layer 4 via the porous conductive layer 5, and the solvent is evaporated to form the perovskite compound 6 in the voids of the porous layer 4.

[0022] Here, the photoelectric conversion element 10 is characterized by having first convex portions 4ap that protrude from the end of the porous layer 4 toward the porous conductive layer 5. The presence of the first convex portions 4ap can prevent a portion of the dropped precursor solution of the perovskite compound 6 from flowing out of the stacked structure. This allows a sufficient amount of the perovskite compound 6 to fill the voids in the porous layer 4, resulting in a photoelectric conversion module 100 with high conversion efficiency. On the other hand, if the first convex portions 4ap are not provided, the dropped precursor solution is likely to flow out of the porous layer 4, resulting in insufficient filling of the perovskite compound into the voids in the porous layer 4 and making it difficult to achieve high conversion efficiency. Below, a photoelectric conversion element 10 having the first convex portions 4ap will be described.

[0023] 2. Photoelectric Conversion Element Fig. 3 is a cross-sectional view taken along III-III of the photoelectric conversion element 10 shown in Fig. 1. As shown in Fig. 3, the photoelectric conversion element 10 comprises, from below, a substrate 1, a transparent conductive film 2, an electron transport layer 3, a porous layer 4 including a first layer 4a and a second layer 4b provided below the first layer 4a, and a porous conductive layer 5, and comprises a perovskite compound 6 in the voids of the porous layer 4. Each component will be described in detail below.

[0024] [Substrate] The substrate 1 is the substrate of the photoelectric conversion element 10 and is made of a transparent or light-transmitting material. The substrate 1 is disposed on the light-incident side of the photoelectric conversion element 10 (including the portion where light is incident, the same applies in the present disclosure). Note that transparent or light-transmitting means that light passes through, but does not exclude materials that reflect or absorb even a small amount of light. It means that the substrate is disposed on the light-receiving side of the solar cell. Therefore, a substrate can be considered transparent if it is disposed at least on the light-receiving side. In other words, a transparent or light-transmitting substrate means a substrate disposed on the light-receiving side of the photoelectric conversion element. Note that the substrate 1 is the substrate of the photoelectric conversion element 10 and is the same as or includes a substrate or base.

[0025] Examples of materials that can be used for the substrate 1 include plastics such as PET and polyimide, and glass. By using a flexible substrate, the solar cell itself can be made flexible.

[0026] When the material of the substrate 1 is a transparent resin such as an organic film, the photoelectric conversion element 10 may have a barrier layer (not shown) on the substrate 1. In this way, it is possible to prevent moisture and the like from penetrating into the porous layer 4.

[0027] The thickness of the substrate 1 may be about 100 μm to 5000 μm. The substrate 1 does not necessarily need to be light-transmitting. In other words, the photoelectric conversion function is ensured as long as the photoelectric conversion element has even a light-transmitting portion, and the substrate 1 does not necessarily need to be light-transmitting.

[0028] [Transparent Conductive Film] The transparent conductive film 2 is a conductive film on the light-receiving surface side of the photoelectric conversion element 10. Examples of materials constituting the transparent conductive film 2 include transparent conductive materials (particularly, transparent conductive oxides (TCOs)) and non-transparent conductive materials. Examples of transparent conductive materials include indium tin oxide (ITO), tin oxide (SnO ２Examples of suitable conductive materials include fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), indium zinc oxide (IZO), and gallium-doped zinc oxide (GZO). Furthermore, the film may be formed by a known method. For example, sputtering, CVD, vapor deposition, etc. may be used. A transparent conductive material refers to a material that, even if its physical properties are non-transparent at a certain thickness, can become transparent depending on the thickness of the material and therefore can be used as a conductive film on the light-receiving surface side of a solar cell 100. The term "film" does not specify thickness or width, and includes patterned or island-shaped films and films with portions of different thicknesses. A film preferably has a substantially constant thickness. Unless otherwise specified, the terms "approximately" and "approximately" mean that variations within the range of manufacturing error are allowed, and preferably indicate a variation of plus or minus 15% of the numerical value. In this disclosure, unless otherwise specified, thickness, width, etc. are confirmed by cross-sectional observation. For example, when observing using an SEM, it is sufficient to observe a single 400 nm-wide cross-sectional SEM image, and thickness, width, etc., within that range; it is not necessary to confirm all cross sections. In other words, a "substantially constant thickness" can be said to be a substantially constant thickness if the thickness in a single 400 nm-wide cross-sectional SEM image is within a range of plus or minus 15% of the average thickness. Note that the transparent conductive film does not necessarily have to be transparent. In other words, the photoelectric conversion function is ensured as long as there is even a partial transparent portion in the photoelectric conversion element, and the conductive film does not necessarily have to be transparent.

[0029] [Electron Transport Layer] The electron transport layer 3 has the function of transporting electrons generated in the perovskite compound 6 provided in the voids of the porous layer 4. Here, for example, the electrons generated in the perovskite compound 6 are transported to the transparent conductive film 2. Preferably, the electron transport layer 3 has the function of blocking holes generated in the perovskite compound 6. The layer disposed on the transparent conductive film 2 side of the porous layer 4 of the photoelectric conversion element 10 naturally has an electron transport function. As long as the electron transport layer 3 is disposed on the transparent conductive film 2 side of the porous layer 4 and the solar cell 100 functions as a photoelectric conversion element, the electron transport function of the electron transport layer 3 does not need to be confirmed. As long as the solar cell 100 functions as a photoelectric conversion element, the layer disposed on the electron transport side of the perovskite compound is referred to as the electron transport layer. The electron transport layer 3 preferably contains a material that easily transports electrons generated in the perovskite compound 6 to the transparent conductive film 2.

[0030] The electron transport layer 3 may be made of, for example, tin oxide, titanium oxide, zinc oxide, or the like. The layer thickness may be, for example, but not limited to, 10 nm to 100 nm. The layer may be formed by a known method. For example, sputtering, die coating, screen printing, or the like may be used.

[0031] The electron transport layer 3 may include a dense titanium oxide layer with a relatively small porosity.

[0032] [Porous Layer] The dense material constituting the electron transport layer 3 and the porous material constituting the porous layer 4 will now be described. The term "layer" does not specify thickness or width, but includes patterned or island-shaped structures and structures with varying thicknesses. A layer preferably has a substantially uniform thickness. The term "dense material" refers to materials such as dense, compact, and compact structures, and includes the same or equivalent terms. The term "porous material" refers to materials such as perovskite compounds, porous structures, and mesoporous structures, and includes the same or equivalent terms. The term "porous material" refers to materials that can contain, in their void spaces, substances other than those constituting porous structures (hereinafter referred to as perovskite compounds, etc.). The term "dense material" refers to materials with extremely small voids. In other words, 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. In this disclosure, unless otherwise specified, SEM observations can be performed on cross-sectional SEM images with a width of 400 nm, and confirmation is sufficient. For example, if the maximum width of voids in a single 400 nm-wide cross-sectional SEM image is less than 5 nm, the layer can be said to be dense. Preferably, a dense material is one that can suppress the penetration of perovskite compounds and ensure that no perovskite compounds are present on one side of the thickness direction of the dense material. More preferably, a dense material means one that cannot contain perovskite compounds or the like in the voids, or one that does not have a portion where perovskite compounds or the like are present continuously throughout the thickness of the dense material. In other words, if a dense material cannot be confirmed by the maximum width of voids, it is sufficient that observation by SEM or EDX reveals that there are no portions where perovskite compounds or the like are present throughout the layer thickness. In the present disclosure, unless otherwise stated, SEM observation can be performed on a 400 nm-wide cross-sectional SEM (or EDX) image and confirmed. For example, if a 400 nm wide cross-section is observed by SEM or EDX and there is no portion in which the perovskite compound is present throughout the layer thickness, the layer can be said to be dense. Note that the definition of dense as being one in which the voids are extremely small takes precedence, and if this does not confirm the denseness, the above preferred definition can be applied, and if this still does not confirm the denseness, the above even more preferred definition can be applied.Here, dense titanium oxide is used as an example of the electron transport layer 3, but the material is not limited as long as it is disposed closer to the transparent conductive film 2 than the porous layer 4 of the photoelectric conversion element 10, and it is not necessary to confirm that it naturally has the function. As the electron transport layer 3, for example, inorganic oxides such as zinc oxide, indium oxide, tin oxide, aluminum oxide, and gallium oxide, typically N-type inorganic oxides, inorganic sulfides such as tin sulfide, indium sulfide, and zinc sulfide, typically N-type inorganic sulfides, etc. can be used.

[0033] The porous layer 4 is a porous layer. The porous layer 4 has voids. The perovskite compound 6 is provided in the voids. The perovskite compound absorbs light, allowing the photoelectric conversion element 10 to perform photoelectric conversion.

[0034] The porous layer 4 preferably contains a metal oxide. For example, a porous metal oxide can be used as the porous layer 4. By making the porous layer 4 porous, the precursor solution of the perovskite compound 6 can easily permeate the porous layer 4.

[0035] The porous layer 4 may be an aggregate of metal oxide fine particles. The porous layer 4 includes a porous material containing an oxide containing one or more of Ti, Sr, Zr, Al, and Si. For example, porous titanium oxide, porous strontium titanate, porous zirconium oxide, porous aluminum oxide, porous silicon oxide, etc. can be used.

[0036] As shown in FIG. 3, the porous layer 4 includes a first layer 4a and a second layer 4b provided below and connected to the first layer 4a.

[0037] The first layer 4a preferably has, on at least one side of its edge, a first protrusion 4ap that protrudes toward the porous conductive layer 5. Since the first protrusion 4ap protrudes toward the porous conductive layer 5 (+Z direction), it is possible to prevent a portion of the dropped precursor solution of the perovskite compound 6 from flowing out of the laminated structure. The laminated structure is a structure made up of the porous layer 4 and the porous conductive layer 5.

[0038] The first layer 4a has a first-layer first region S41a, which is a region in the planar direction where the first convex portion 4ap is not present, and a first-layer second region S41b, which is a region in the planar direction (Y direction) where the first convex portion 4ap is present. That is, the film thickness of the first-layer second region S41b is thicker than the film thickness of the first-layer first region S41a. The first-layer first region S41a also includes a central portion of the first layer 4a. The central portion is the central portion of the first layer 4a in the X or Y direction.

[0039] The thickness of the first-layer first region S41a is, for example, 1 μm or more and 6 μm or less. The thickness of the first-layer second region S41b having the first convex portion 4ap is preferably 1.1 times or more, more preferably 1.2 times or more, even more preferably 1.4 times or more, and still more preferably 2.0 times or more, the thickness of the first-layer first region S41a.

[0040] The porous layer 4 may be formed by a known method. For example, it may be formed by die coating, screen printing, gravure printing, or the like using ink containing metal oxide fine particles. For example, when using screen printing, the first convex portions 4ap can be formed by making the mesh size corresponding to the position where the first layer 4a is to be formed larger than that of other locations on a screen printing plate for forming the first layer 4a. Note that the method is not limited to the above, and any method may be used as long as the first convex portions 4ap are formed.

[0041] The first layer 4a preferably includes a porous material made of an insulator. For example, porous zirconium oxide, porous aluminum oxide, porous silicon oxide, etc. can be used as the first layer 4a. For example, a porous material including one or more of zirconium oxide, aluminum oxide, and silicon oxide can be used as the first layer 4a. In other words, the first layer 41a preferably includes one or more of the group consisting of zirconium oxide, aluminum oxide, and silicon oxide.

[0042] The second layer 4b may be made of, for example, porous titanium oxide or porous strontium titanate. A porous material containing at least one of titanium oxide and strontium titanate may also be used for the second layer 4b. In other words, the second layer 4b preferably contains titanium oxide or strontium titanate. The film may be formed by a known method. For example, die coating, screen printing, gravure printing, or the like may be used.

[0043] The first convex portions 4ap are preferably provided near at least one side of the first layer 4a in plan view. Here, "near one side" refers preferably to a region within 2 mm, more preferably within 1 mm, and even more preferably within 400 μm of the edge of the first layer 4a in plan view. Furthermore, a region in which the thickness of the porous layer 4 gradually decreases may exist between the edge of the first layer 4a and the first convex portions 4ap in plan view. In this case, this region is preferably within 2 mm, more preferably within 1 mm, and even more preferably within 400 μm of the edge of the first layer 4a in plan view. Furthermore, the first layer 4a is preferably rectangular in plan view, and the first convex portions 4ap are preferably provided along at least a short side of the rectangular shape. That is, in FIG. 1, the first convex portions 4ap are provided along the X direction. Providing the first convex portions 4ap on the short side can prevent the porous layer 4 from flowing into the outer frame portion of the photoelectric conversion element 10 where no cell structure is present.

[0044] It is also preferable that the first convex portions 4ap are provided along at least the long sides of the rectangular shape, which further prevents a portion of the dropped precursor solution of the perovskite compound 6 from flowing out of the layered structure.

[0045] As shown in FIG. 3, the entire surface of the first layer first region S41a is preferably in contact with the porous conductive layer 5.

[0046] 3, it is preferable that at least a portion of the first-layer second region S41b contacts the porous conductive layer 5. In this way, convex portions 5ap of the porous conductive layer 5 are formed in the region of the porous conductive layer 5 that contacts the first-layer second region S41b, which further prevents a portion of the dropped precursor solution of the perovskite compound 6 from flowing out of the laminated structure. It is also more preferable that at least a portion of the first convex portions 4ap contacts the porous conductive layer 5. In this case, the height of the convex portions 5ap of the porous conductive layer 5 increases, which is more effective.

[0047] The porous layer 4 is formed by forming the second layer 4b and then the first layer 4a. The first layer 4a may be thicker than the second layer 4b.

[0048] [Perovskite Compound] The perovskite compound 6 is provided in the voids of the porous layer 4. As described above, after the porous layer 4 is formed, a precursor solution of the perovskite compound 6 is dripped onto the porous layer 4 to penetrate and fill the voids. As described above, the presence of the first convex portions 4ap prevents a portion of the dripped precursor solution of the perovskite compound 6 from flowing out of the laminated structure. This allows a sufficient amount of the perovskite compound 6 to be filled into the voids of the porous layer 4, resulting in high conversion efficiency. Considering that a photoelectric conversion element has a photoelectric conversion function, it is natural that the perovskite compound has the photoelectric conversion function. Therefore, as long as the photoelectric conversion element has the photoelectric conversion function, there is no need to specifically confirm that the perovskite compound has the photoelectric conversion function.

[0049] A known compound is used as the perovskite compound 6. A precursor solution of the perovskite compound is permeated into the porous layer 4 to fill it, and then dried.

[0050] The perovskite compound is composed of a compound represented by the general formula: ABX (1). While the composition ratio is preferably 1:1:3, it does not necessarily have to be 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 photoelectric conversion element has a photoelectric conversion function, i.e., the perovskite compound is contained in the porous layer 4 of the photoelectric conversion element, the composition may have the degree of freedom described above. In general formula (1), A represents 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 represents a metal atom or molecule (including a metal cation, as defined in the present disclosure); and X represents 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. Because a perovskite compound functions as a material that absorbs light and converts it into electricity when contained in the porous layer 4 of a photoelectric conversion element, this fact should also be taken into consideration. That is, a perovskite compound can be confirmed by, for example, detecting organic molecules, metal atoms, and halogen atoms. Furthermore, a perovskite compound can be confirmed by detecting elements corresponding to A, B, and X, so long as the photoelectric conversion element has a photoelectric conversion function. For example, molecules containing carbon, nitrogen, and hydrogen are suitable as organic molecules, and therefore, carbon, nitrogen, hydrogen, a metal element, and a halogen element or chalcogen element can be detected. Furthermore, a perovskite compound can be confirmed by detecting elements corresponding to A, B, and X, so long as the photoelectric conversion element has a photoelectric conversion function. For example, cesium or rubidium is suitable as inorganic atoms, and therefore, cesium or rubidium, a metal element, and a halogen element or chalcogen can be detected. Furthermore, it is natural that a perovskite compound has a crystalline structure or semiconductor properties in order for a photoelectric conversion element to have a photoelectric conversion function, and it is not necessary to confirm that it has a crystalline structure or semiconductor properties.The porous layer 4 may contain a compound other than a perovskite compound.

[0051] An organic-inorganic hybrid compound may be included instead of a perovskite 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 organic materials. In other words, organic refers to materials that contain carbon as one of their primary components, excluding carbon materials such as graphite. "Inorganic" refers to materials that are not organic. In general formula (1), examples of organic molecules represented by A include alkylamines, alkylammoniums, and nitrogen-containing heterocyclic compounds. In perovskite compound (1), the organic molecule represented by A may be a single organic molecule or two or more organic molecules.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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. Furthermore, in general formula (1), the organic molecule represented by A is also preferably a formamidinium cation.

[0056] 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.

[0057] 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.

[0058] 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 The perovskite compound is more preferably a compound represented by 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 100 can be further improved.

[0059] [Porous Conductive Layer] The porous conductive layer 5 is a porous conductive layer. Examples of materials that can be used for the porous conductive layer 5 include carbon black, graphite, and carbon fine particles. In other words, the porous conductive layer 5 preferably contains at least one of the group consisting of carbon black, graphite, and carbon fine particles. The layer may be formed by a known method. Examples of methods that can be used include die coating, screen printing, and gravure printing. The conductive layer has a conductive function, but as long as it is located closer to the porous conductive layer 5 than the porous layer 4 of the photoelectric conversion element 10, it naturally has this function. Therefore, as long as the photoelectric conversion element 10 functions when it is located on the porous conductive layer 5 side, there is no need to confirm this function.

[0060] Furthermore, the porous conductive layer 5 may have a rectangular shape in plan view as shown in Fig. 1. Furthermore, the short sides (X direction in Fig. 1) of the porous conductive layer 5 may be provided within the first layer second region S41b as shown in Fig. 3. That is, the porous conductive layer end portion 5a may be provided within the first layer second region S41b. In this way, convex portions are formed in the regions of the porous conductive layer 5 above the first convex portions 4ap, thereby preventing a portion of the dropped precursor solution of the perovskite compound 6 from flowing out of the stacked structure.

[0061] As shown in FIG. 3, the porous conductive layer end 5a is provided between the outer end 4apb and the inner end 4apa of the first convex portion 4ap.

[0062] Furthermore, one of the two long sides (Y direction in FIG. 1 ) of the porous conductive layer 5 may be provided on the first layer second region S41b. In this way, a convex portion is also formed on the porous conductive layer 5, which can prevent a portion of the dropped precursor solution of the perovskite compound 6 from flowing out of the stacked structure, thereby increasing the conversion efficiency. The perovskite compound may be contained in the voids of the porous conductive layer 5.

[0063] As described above, the photoelectric conversion element 10 according to the present disclosure prevents a portion of the dropped precursor solution of the perovskite compound 6 from flowing out of the layered structure, and has high conversion efficiency.

[0064] Modifications of the photoelectric conversion element 10 will be described below.

[0065] The photoelectric conversion element 11 shown in Fig. 4 is a first modification of the photoelectric conversion element 10 shown in Fig. 3. As shown in Fig. 4, the porous conductive layer end 5a is provided inside the inner end 4apa of the first convex portion 4ap (towards the center of the photoelectric conversion element 11). Because the photoelectric conversion element 11 has the first convex portion 4ap, the precursor liquid of the perovskite compound is less likely to flow out of the layered structure, making it easier to obtain good photoelectric conversion efficiency.

[0066] 4, it is preferable that at least a portion of the first layer first region S41a be in contact with the porous conductive layer 5. This improves the uniformity of the thickness of the porous conductive layer 5, thereby improving the yield.

[0067] 4, the porous conductive layer 5 preferably has a rectangular shape in plan view as shown in Fig. 1, and the short sides (sides in the X direction) of the porous conductive layer 5 are preferably provided on the first layer first region S41a. This improves the uniformity of the thickness of the porous conductive layer 5 and improves the yield.

[0068] 4, one of the two long sides (Y direction in FIG. 1) of the porous conductive layer 5 is preferably provided on the first layer first region S41a, which improves the thickness uniformity of the porous conductive layer 5 and improves the yield.

[0069] The photoelectric conversion element 12 shown in Fig. 5 is a second modification of the photoelectric conversion element 10 shown in Fig. 3. As shown in Fig. 5, after forming the second layer 4b, the first layer 4a may be formed, and then the first convex portion 4ap may be formed by further laminating the first layer 4a on its outer edge portion. In this manner, the first-layer second region 41b, which is thicker than the first-layer first region S41a, can be formed on the outer edge portion of the porous layer 4.

[0070] The photoelectric conversion element 13 shown in Fig. 6 is a third variation of the photoelectric conversion element 10 shown in Fig. 3. As shown in Fig. 6, after forming the second layer 4b, the first layer 4a may be formed by separately forming the first-layer first region S41a of the first layer 4a and the first-layer second region S41b, which is thicker than the first-layer first region S41a, on the outer edge of the second layer 4b. In this case, as shown in Fig. 6, a first convex portion 4ap is formed on the outer edge of the first layer 4a, protruding further in the direction toward the porous conductive layer 5 (in the +Z direction) than the upper end of the first-layer first region S41a.

[0071] The photoelectric conversion element 14 shown in FIG. 7 is a fourth variation of the photoelectric conversion element 10 shown in FIG. 3. As shown in FIG. 7, the second layer 4b has second convex portions 4bp protruding toward the porous conductive layer 5 on at least one edge. The second layer 4b has a second-layer first region S42a, which is a region in the planar direction where the second convex portions 4bp are not present, and a second-layer second region S42b, which is a region in the planar direction where the second convex portions 4bp are present. The second-layer second region S42b is characterized in that the thickness of the second-layer second region S42b is thicker than the thickness of the second-layer first region S42a. By providing the second convex portions 4bp in the second layer 4b, first convex portions 4ap are provided in the first layer 4a accordingly. In other words, even if the thickness of the first layer 4a in the first region S41a of the first layer is the same as that in the second region S41b of the first layer, the first convex portion 4ap is formed in the first layer 4a on the second convex portion 4bp. The first convex portion 4ap is located above the second convex portion 4bp.

[0072] In this way, it is possible to prevent a part of the dropped precursor solution of the perovskite compound 6 from flowing out to the outside of the laminated structure.

[0073] The photoelectric conversion element 15 shown in Fig. 8 is a fifth variation of the photoelectric conversion element 10 shown in Fig. 3. As shown in Fig. 7, the second layer 4b has second convex portions 4bp protruding toward the porous conductive layer 5 on at least one side of the edge. The second layer 4b has a second-layer first region S42a, which is a region in the planar direction where the second convex portions 4bp are not present, and a second-layer second region S42b, which is a region in the planar direction where the second convex portions 4bp are present. The second-layer first region S42a includes a central portion of the second layer 4b. The central portion is the central portion of the second layer 4b in the X or Y direction. 8 differs from the embodiment shown in FIG. 7 in that the thickness of the second layer 4b in the second-layer-second region S42b is thicker than the thickness of the second layer 4b in the second-layer-first region S42a, and the thickness of the first layer 4a in the first-layer-second region S41b is thicker than the thickness of the first layer 4a in the first-layer-first region S41a. The first protrusions 4ap are preferably located above the second protrusions 4bp. In this case, the amount of protrusion of the first protrusions 4ap toward the porous conductive layer 5 (+Z direction) can be further increased when viewed from the top end of the first-layer-second region S41a.

[0074] In this way, it is possible to more effectively prevent a part of the dropped precursor solution of the perovskite compound 6 from flowing out to the outside of the laminated structure.

[0075] The positional relationship between the porous conductive layer end portion 5a and the first convex portion 4ap, and the positional relationship between the porous conductive layer end portion 5a and the first-layer second region S41b shown in Figures 7 and 8 are as described in Figures 3 and 4. Furthermore, the positional relationship between the porous conductive layer end portion 5a and the second convex portion 4bp, and the positional relationship between the porous conductive layer end portion 5a and the second-layer second region S42b may be similar to the positional relationship between the porous conductive layer end portion 5a and the first convex portion 4ap, and the positional relationship between the porous conductive layer end portion 5a and the first-layer second region S41b, respectively.

[0076] The method of forming the first convex portion 4ap and the second convex portion 4bp in FIGS. 7 and 8 can be the same as the method of forming the first convex portion 4ap described with reference to FIG. 5 or FIG.

[0077] As described above, photoelectric conversion elements 10, 11, 12, 13, 14, and 15 according to the present disclosure can improve conversion efficiency and yield.

[0078] 3. Photovoltaic Conversion System Fig. 9 is a schematic diagram of a photovoltaic conversion system 1000 according to the present disclosure. As shown in Fig. 9, the photovoltaic conversion system 1000 according to the present disclosure includes the above-described photovoltaic conversion module 100, a power conditioner 101, a distribution board 102, a power meter 103, a storage battery 104, and electrical equipment 105. The photovoltaic conversion system 1000 shown in Fig. 9 is provided with one each of the photovoltaic conversion module 100, the power conditioner 101, the distribution board 102, the power meter 103, the storage battery 104, and the electrical equipment 105, but a plurality of each may be provided.

[0079] The power conditioner 101 controls the current and voltage so that the power output from the photovoltaic conversion module 100 is optimized, and performs the desired power distribution while monitoring the output power of the photovoltaic conversion module 100 and the charge amount of the storage battery 104, and outputs power to the storage battery 104 and the distribution board 102. At this time, the power conditioner 101 outputs DC power to the storage battery 104 and AC power to the distribution board 102. In other words, the power conditioner 101 has the function of converting DC power into AC power.

[0080] The distribution board 102 supplies the AC power received from the power conditioner 101 to the electrical equipment 105 and the power meter 103 in a desired distribution while monitoring the output power of the power conditioner 101 and the power consumption of the electrical equipment 105 .

[0081] The power meter 103 measures the power supplied from the distribution board 102 and supplies it to the commercial power system.

[0082] The electrical device 105 may be connected to the power conditioner 101 instead of being connected to the distribution board 102. In this case, the power conditioner 101 performs the desired power distribution while monitoring the output power of the photovoltaic conversion module 100, the charge amount of the storage battery 104, and the power consumption of the electrical device 105, and supplies AC power to the distribution board 102, DC power to the storage battery 104, and AC power to the electrical device 105. If the electrical device 105 is for DC power, DC power may be supplied.

[0083] As described above, the photoelectric conversion element, photoelectric conversion module, and photoelectric conversion system according to the present disclosure can prevent a portion of the dropped precursor solution of the perovskite compound from flowing out of the stacked structure, thereby achieving high conversion efficiency.

[0084] Although each embodiment and each example of the present disclosure have been described in detail above, it will be readily apparent to those skilled in the art that many modifications are possible without substantially departing from the novel features and effects of the present disclosure. Therefore, all such modifications are intended to be included within the scope of the present disclosure.

[0085] For example, a term described at least once in the specification or drawings together with a different term having a broader or equivalent meaning can be replaced with that different term anywhere in the specification or drawings. Furthermore, the configurations and operations of the photoelectric conversion element, photoelectric conversion module, and photoelectric conversion system are not limited to those described in the embodiments and examples of the present disclosure, and various modifications are possible.

Claims

1. A photoelectric conversion element comprising: a conductive film; an electron transport layer provided on the conductive film; a porous layer provided on the electron transport layer and including a first layer and a second layer provided below the first layer; a porous conductive layer provided on the porous layer; and a perovskite compound provided in voids in the porous layer, wherein the first layer has a first convex portion protruding in the direction of the porous conductive layer, and a first region of the first layer, which is a region in the planar direction where the first convex portion is not present, includes a central portion of the first layer.

2. A photoelectric conversion element according to claim 1, characterized in that the first layer has a first convex portion on at least one side of its edge that protrudes toward the porous conductive layer.

3. A photoelectric conversion element according to claim 1 or 2, characterized in that the first convex portion is provided near at least one side of the first layer in a plan view.

4. A photoelectric conversion element described in any one of claims 1 to 3, characterized in that the first layer is rectangular in plan view, and the first convex portion is provided along at least a short side of the rectangular shape.

5. A photoelectric conversion element described in any one of claims 1 to 3, characterized in that the first layer is rectangular in plan view, and the first convex portion is provided along at least a long side of the rectangular shape.

6. A photoelectric conversion element described in any one of claims 1 to 5, characterized in that the second layer has a second convex portion protruding in the direction of the porous conductive layer, and a second layer first region, which is a region in the planar direction where the second convex portion is not present, includes a central portion of the second layer.

7. A photoelectric conversion element according to any one of claims 1 to 5, characterized in that the second layer has a second convex portion protruding in the direction of the porous conductive layer.

8. The photoelectric conversion element according to claim 7, wherein the film thickness of the first region of the first layer is greater than the film thickness of the second region of the first layer.

9. A photoelectric conversion element according to any one of claims 1 to 8, characterized in that at least a portion of the first region of the first layer is in contact with the porous conductive layer.

10. A photoelectric conversion element described in any one of claims 1 to 9, characterized in that at least a portion of the first layer second region, which is the region in the planar direction in which the first convex portion exists, is in contact with the porous conductive layer.

11. A photoelectric conversion element described in any one of claims 1 to 10, characterized in that the porous conductive layer is rectangular in a planar view, and the short side of the porous conductive layer is provided on the first region of the first layer.

12. A photoelectric conversion element described in any one of claims 1 to 10, characterized in that the porous conductive layer is rectangular in a planar view, and the short side of the porous conductive layer is provided within a first layer second region, which is a region in the planar direction in which the first convex portion exists.

13. A photoelectric conversion element described in any one of claims 1 to 10, characterized in that the porous conductive layer is rectangular in a planar view, and one of the two long sides of the porous conductive layer is provided on the first region of the first layer.

14. A photoelectric conversion element described in any one of claims 1 to 10, characterized in that the porous conductive layer is rectangular in a planar view, and one of the two long sides of the porous conductive layer is provided on a first layer second region, which is a region in the planar direction in which the first convex portion exists.

15. A photoelectric conversion element described in any one of claims 1 to 14, characterized in that an end of the porous conductive layer is provided between an outer end and an inner end of the first convex portion.

16. A photoelectric conversion element described in any one of claims 1 to 14, characterized in that an end of the porous conductive layer is provided inside the inner end of the first convex portion.

17. The photoelectric conversion element according to any one of claims 1 to 16, characterized in that the porous layer contains a metal oxide.

18. A photoelectric conversion element according to any one of claims 1 to 17, characterized in that the porous layer contains at least one of the group consisting of titanium oxide, zirconium oxide, aluminum oxide and silicon oxide.

19. The photoelectric conversion element according to any one of claims 1 to 18, characterized in that the second layer contains titanium oxide.

20. A photoelectric conversion element according to any one of claims 1 to 19, characterized in that the first layer contains at least one of the group consisting of zirconium oxide, aluminum oxide and silicon oxide.

21. A photoelectric conversion element according to any one of claims 1 to 20, characterized in that the porous conductive layer contains at least one of the group consisting of carbon black, graphite, and carbon particles.

22. A photoelectric conversion element described in any one of claims 1 to 21, characterized in that the thickness of the first layer second region, which is the region in the planar direction in which the first convex portion exists, is 1.1 times or more the thickness of the first layer first region.

23. A photoelectric conversion element described in any one of claims 1 to 22, characterized in that the thickness of the first layer second region, which is the region in the planar direction in which the first convex portion exists, is 2.0 times or more the thickness of the first layer first region.

24. A photoelectric conversion module comprising the photoelectric conversion element according to any one of claims 1 to 23.

25. A photoelectric conversion system comprising: the photoelectric conversion module according to claim 24; and a control circuit.

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