Photoelectric conversion module and method for manufacturing the same

Abstract

The present invention provides a photoelectric conversion element that can achieve uniformity in the amount of liquid dispensed from each cell. [Solution] The photoelectric conversion module 1 has a plurality of photoelectric conversion elements 10. The photoelectric conversion element 10 is provided with a first conductive layer 3, a photoelectric conversion layer 5, and a second conductive layer 7 in that order from the substrate 2. The photoelectric conversion layer 5 contains a perovskite compound formed in the voids of the porous layer. A protective wall portion 8 is formed to surround the photoelectric conversion layer 5. A protective wall portion 8 is provided for each photoelectric conversion element 10.

Description

[Technical Field]

[0001] The present disclosure relates to a photoelectric conversion module using a perovskite compound and a method for producing the same. [Background Art]

[0002] In recent years, solar cells have become widespread as a means of utilizing renewable energy. As solar cells, those using inorganic photoelectric conversion elements (for example, silicon-based solar cells, CIGS-based solar cells, CdTe-based solar cells, etc.) are widely used, while solar cells using organic photoelectric conversion elements (for example, organic thin-film solar cells, dye-sensitized solar cells, perovskite solar cells, etc.) are also under investigation. In particular, perovskite solar cells have been actively researched from the perspective that they can be manufactured at lower cost compared to conventional solar cells (see, for example, Patent Document 1). [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2016-178167 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] A conventional solar cell includes a base material, a base layer laminated on the base material, and a light absorption layer containing an organic-inorganic perovskite compound formed inside the base layer. The base layer is formed by spraying at least one of N-type semiconductor fine particles and insulator fine particles having the organic-inorganic perovskite compound adhered thereto onto the base material.

[0005] Conventional solar cell modules involve coating the photoelectric conversion layer with a solution containing a perovskite compound or its precursor. However, the solution does not remain on the photoelectric conversion layer but flows into the cell region of adjacent photoelectric conversion elements, which presents a problem. As a result, it is not possible to control the desired amount of solution dispensed for each cell (solar cell), leading to problems such as reduced conversion efficiency and unevenness due to variations in the amount of solution dispensed.

[0006] This disclosure is made to solve the above-mentioned problems and aims to provide a photoelectric conversion element that can achieve uniformity in the amount of liquid dispensed from each cell, and a method for manufacturing the same. [Means for solving the problem]

[0007] The photoelectric conversion module according to this disclosure is a photoelectric conversion module having a plurality of photoelectric conversion elements, wherein the photoelectric conversion elements are provided with a first conductive layer, a photoelectric conversion layer, and a second conductive layer in order from the substrate, the photoelectric conversion layer contains a perovskite compound formed in the voids of the porous layer, a protective wall portion is formed to surround the photoelectric conversion layer at a distance from it, and the protective wall portion is provided for each photoelectric conversion element.

[0008] The photoelectric conversion module according to this disclosure may be configured such that non-device regions are provided between device regions corresponding to the photoelectric conversion elements, and the protective wall portion is provided in the non-device region.

[0009] The photoelectric conversion module according to this disclosure may be configured such that non-device regions are provided between device regions corresponding to the photoelectric conversion elements, and the barrier portion is provided across the boundary between the device region and the non-device region.

[0010] In the photoelectric conversion module according to this disclosure, the second conductive layer may have a protruding portion that extends further toward the non-device area than the photoelectric conversion layer in the adjacent direction where adjacent photoelectric conversion cells are lined up, and the protective wall portion may be provided overlapping the protruding portion.

[0011] In the photoelectric conversion module according to this disclosure, the protective wall portion may be configured to be provided on top of the end of the second conductive layer in the adjacent direction where adjacent photoelectric conversion cells are lined up.

[0012] In the photoelectric conversion module according to this disclosure, the second conductive layer may have a protruding portion that extends further toward the non-device area than the photoelectric conversion layer in the adjacent direction, and the protective wall portion may be provided overlapping the protruding portion.

[0013] In the photoelectric conversion module according to this disclosure, the protective wall portion may be made of glass.

[0014] In the photoelectric conversion module according to this disclosure, the porous layer may include a porous electron transport layer and a porous insulating layer.

[0015] The photoelectric conversion module according to this disclosure is a photoelectric conversion module having a plurality of photoelectric conversion elements, wherein the photoelectric conversion elements are provided with a first conductive layer, a photoelectric conversion layer, and a second conductive layer in order from the substrate, the photoelectric conversion layer contains a perovskite compound formed in the voids of the porous layer, a protective wall portion is formed on the outside of the photoelectric conversion layer when viewed in cross-section, and the protective wall portion is provided between the photoelectric conversion elements.

[0016] The method for manufacturing a photoelectric conversion module according to the present disclosure is a method for manufacturing a photoelectric conversion module having a plurality of photoelectric conversion elements, the method comprising the step of providing a first conductive layer, a photoelectric conversion layer, and a second conductive layer in order from a substrate in the photoelectric conversion element, the photoelectric conversion layer comprising a perovskite compound formed in the voids of a porous layer, and the method comprising the step of providing a protective wall surrounding the photoelectric conversion layer for each photoelectric conversion element. [Effects of the Invention]

[0017] According to the present disclosure, providing a barrier portion for each photoelectric conversion element can prevent the solution dropped onto the porous layer from flowing out to the region of an adjacent photoelectric conversion element. Accordingly, the desired dropping amount can be controlled for each photoelectric conversion element, and variation in the dropping amount can be suppressed, so that the conversion efficiency can be stabilized. [BRIEF DESCRIPTION OF DRAWINGS]

[0018] [Figure 1] FIG. 1 is a schematic cross-sectional view showing the photoelectric conversion module according to the first embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic cross-sectional view showing a photoelectric conversion module of a comparative example. [Figure 3] FIG. 3 is a schematic cross-sectional view showing the photoelectric conversion module according to the second embodiment of the present disclosure. [Figure 4] FIG. 4 is a schematic cross-sectional view showing the photoelectric conversion module according to the third embodiment of the present disclosure. [MODE FOR CARRYING OUT THE INVENTION]

[0019] (First Embodiment) Hereinafter, the photoelectric conversion module according to the first embodiment of the present disclosure will be described with reference to the drawings.

[0020] FIG. 1 is a schematic cross-sectional view showing the photoelectric conversion module according to the first embodiment of the present disclosure.

[0021] The photoelectric conversion element 10 according to the embodiment of this disclosure has a first conductive layer 3, a dense electron transport layer 4, a photoelectric conversion layer 5, a hole transport layer 6, and a second conductive layer 7 laminated on a substrate 2. Multiple photoelectric conversion elements 10 are arranged side-by-side on the substrate 2, and a photoelectric conversion module 1 is constructed by connecting multiple photoelectric conversion elements 10 in series. For explanatory purposes, the direction in which multiple photoelectric conversion elements 10 are arranged in series may be referred to as the adjacent direction X. Furthermore, the explanation may focus on one of the multiple photoelectric conversion elements 10 (the right photoelectric conversion element 10 in Figure 1), while the remaining photoelectric conversion elements 10 (such as the left photoelectric conversion element 10 in Figure 1) may be referred to as adjacent photoelectric conversion elements 10. Furthermore, for the purpose of explanation below, the portion of the substrate 2 in which the first conductive layer 3, dense electron transport layer 4, photoelectric conversion layer 5, hole transport layer 6, and second conductive layer 7 are stacked to form a single photoelectric conversion element 10 will be referred to as the device region DR, and the portion outside the device region DR, between adjacent photoelectric conversion elements 10, will be referred to as the non-device region HR. In this embodiment, a protective wall portion 8 is provided in the non-device region HR, which is spaced apart from the device region DR and surrounds it.

[0022] Provided that, the device region basically means a region on the base body 2 where all of the first conductive layer 3, the dense electron transport layer 4, the photoelectric conversion layer 5, the hole transport layer 6, and the second conductive layer 7 are stacked and overlapped. In addition to the above basic region, the device region may further include at least the region occupied by the photoelectric conversion layer 5. In addition to the several regions mentioned above, the device region may further include at least the region occupied by the electron transport layer. In addition to the several regions mentioned above, the device region may further include at least the region occupied by the hole transport layer 6. In addition to the several regions mentioned above, the device region may further include at least the region occupied by the second conductive layer 7. In addition, depending on the case, in addition to the several regions mentioned above, the device region may further include at least the region occupied by the first conductive layer 3. Furthermore, regarding the non-device region, although there are the respective device regions described above, it means all regions that are not the device region with respect to each corresponding device region. That is, the non-device region is defined as a region that is not the device region relative to the device region.

[0023] It should be noted that, in the illustration, as the device region DR, a region including at least the regions occupied by the dense electron transport layer 4, the photoelectric conversion layer 5, the hole transport layer 6, and the second conductive layer 7 in addition to the basic region is shown as an example.

[0024] Furthermore, "surrounding a certain region" means, for example, in a microscopic observation of any region from the light-receiving surface side (or the back side opposite the light-receiving surface side), it is sufficient to confirm that at least a portion of each of the two ends of a certain region (for example, any two opposing sides of a certain region) is located outside the ends of the region in the observation images obtained by individually observing each side. Alternatively, if confirmation is difficult with the above microscopic observation, "surrounding a certain region" may be confirmed by performing a cross-sectional observation and confirming that the region is located outside the respective ends in the observation images obtained by individually observing both ends of the region in at least one cross-section. As stated above, confirmation of "surrounding a certain region" is sufficient by observing two points on any two opposing sides or any cross-section, but it is even more preferable to confirm this by observing two points on two opposing sides different from the two opposing sides, or two points on any cross-section perpendicular to any cross-section.

[0025] The base 2 is the base for the photoelectric conversion element 10, and is the same as or includes the substrate or base material. It may be hard and rigid, or it may be flexible and have low rigidity. Examples of the shape of the base 2 include a flat plate and a film. When light is irradiated (light is incident) on the surface of the photoelectric conversion element 10 that faces the base 2 (the bottom surface of the base 2 in Figure 1), that is, when the side of the base 2 is the light-receiving surface, it is preferable that the base 2 is transparent. In this case, examples of materials for the base 2 include glass and heat-resistant transparent resin. When light is irradiated from the opposite side, the base 2 may be opaque. Examples of materials that can be used as the base 2 include organic films. Examples of materials for the organic film include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polyetherimide (PEI), polytetrafluoroethylene (PTFE), polyamideimide (PAI), and polyethylene naphthalate (PEN), but other resins can also be used as long as they meet the requirements. The thickness of the organic film that forms the substrate 2 is preferably around 50 μm to 100 μm. Note that "transparent" means that light is transmitted, but this does not exclude anything that reflects or absorbs even a little light. It is sufficient that light is transmitted appropriately, and this can be considered synonymous with being provided on the light-receiving side of the solar cell (including the part where light is incident, as is the case in this disclosure). Therefore, it can be said that it is transparent if it is provided at least on the light-receiving side of the solar cell.

[0026] The first conductive layer 3 is a transparent electrode layer and is a conductive component. The first conductive layer 3 is formed on the substrate 2, on the surface of the substrate 2, or on one side of the substrate 2 (for example, the upper side), and functions as an electrode for extracting the photovoltaic power of the photoelectric conversion element 10. The first conductive layer 3 is formed of a transparent conductive material, such as conductive transparent materials such as FTO (fluorine-doped tin oxide), CuI (copper iodide), ITO (indium tin oxide), SnO2 (tin oxide), AZO (aluminum zinc oxide), IZO (indium zinc oxide), GZO (gallium zinc oxide), ATO (antimond-doped tin oxide), or conductive transparent polymers. The chemical formulas are representative examples and any compound name is acceptable (similar in this disclosure). Furthermore, while stoichiometric composition ratios of the chemical formulas are desirable, they do not necessarily have to be stoichiometric (similar in this disclosure). The first conductive layer 3 may have a configuration in which a conductive metal such as silver or a fine wire thereof is formed on an oxide film such as a conductive transparent material. The term "film" does not specify a thickness or width, and includes patterned or island-shaped films or films with parts of different thicknesses. Preferably, the film has a substantially constant thickness. Unless otherwise specified, "substantially" or "to a certain extent" refers to the range of manufacturing tolerances, and preferentially indicates that a variation of plus 15% and minus 15% of that value is acceptable. In this disclosure, conductivity means that as long as the solar cell functions as a solar cell, it can be confirmed that the parts with the appropriate material are conductive, and it is not necessary to check the physical properties of the conductive layer to confirm conductivity.

[0027] The first conductive layer 3 is divided into multiple sections and arranged in an island-like manner, spaced apart in the adjacent direction X. Specifically, the first conductive layer 3 is arranged to span from the device region DR of one of the photoelectric conversion elements 10, through the non-device region HR, to the device region DR of the adjacent photoelectric conversion element 10. Approximately in the center of the device region DR, the first conductive layer 3 is divided, and there is a portion on the substrate 2 where the first conductive layer 3 is not provided.

[0028] The dense electron transport layer 4 is a layer capable of transporting electrons generated in the light-absorbing portion (for example, a perovskite compound). The electron transport layer naturally possesses this function as long as the solar cell has the function of photoelectric conversion, and can be considered equivalent to being located on the electron transport side of the light-absorbing portion of the solar cell. Therefore, as long as it is located on the electron transport side of the perovskite compound, it can be said to have an electron transport function. Preferably, the electron transport layer also has the function of blocking hole transport.

[0029] Furthermore, the term "electron transport layer" can refer to both dense electron transport layers and porous electron transport layers, or to each of these layers individually, or it can refer to an electron transport layer as a general concept that includes other layers with electron transport functions.

[0030] In this embodiment, the dense electron transport layer 4 is dense. Dense is also called compact or compact material, and can be the same as or include those materials. Furthermore, it is preferable that the dense layer has few or no pores. It is also preferable that most of these pores are independent and not connected. The dense layer can function as a layer in which liquid hardly seeps into the dense layer even when a liquid is dropped onto it.

[0031] Furthermore, it is preferable that the compact material has almost no voids or, if any, extremely small voids. In this disclosure, compact material means a material in which, upon observation, no light-absorbing portion (in this embodiment, a perovskite compound as an example, and hereinafter described as a perovskite compound) is present on one side in the thickness direction of the compact material (for example, the lower side). In other words, even if a perovskite compound is present on the upper side of the compact material, it is possible to ensure that it does not penetrate and remain absent on the lower side of the compact material. Preferably, the compact material has extremely small voids. Preferably, the compact material has a maximum void width of less than 5 nm. Preferably, the compact material suppresses the penetration of perovskite compounds, and allows for a state in which no perovskite compounds are present on one side in the thickness direction of the compact material. More preferably, dense material means material that cannot contain perovskite compounds in its voids, or material that does not have any portions in which perovskite compounds exist continuously throughout the thickness of the dense portion. In other words, if dense material cannot be confirmed at the maximum width of its voids, it is sufficient that observation by SEM or EDX shows that there are no portions in which perovskite compounds penetrate the thickness of the layer. In this disclosure, unless otherwise contradictory, observation by SEM should be performed on a 400 nm wide cross-sectional SEM (or EDX) image and confirmation should be possible. For example, if a single 400 nm wide cross-sectional SEM or EDX observation shows no portions in which perovskite compounds penetrate the thickness of the layer, then that layer can be said to be dense material.

[0032] The dense electron transport layer 4 can be made of, for example, tin oxide, titanium oxide, zinc oxide, etc. The dense electron transport layer 4 can be formed by known methods, such as sputtering, die coating, or screen printing. The layer thickness can be, for example, 10 nm to 200 nm, but is not limited to this. The term "layer" does not define thickness or width, and includes patterned or island-shaped layers, or layers with different thicknesses. Preferably, the layer is a component with a substantially constant thickness. The dense electron transport layer 4 is provided overlapping a portion of the first conductive layer 3. Specifically, the dense electron transport layer 4 is provided on the first conductive layer 3 located at one end (the left end in Figure 1) in the adjacent direction X of the device region DR.

[0033] The photoelectric conversion layer 5 refers to the layer located between the first conductive layer and the second conductive layer, and is a layer that has the function of converting light into electricity. The photoelectric conversion layer 5 is a layer that includes at least a porous layer and a light-absorbing layer. It is self-evident that as long as the solar cell has a photoelectric conversion function, the photoelectric conversion layer 5 has the function of converting light into electricity, and verification of the photoelectric conversion function is not required. In other words, as long as the solar cell functions as a solar cell, the layer located between the first conductive layer and the second conductive layer has the function of converting light into electricity, and that layer is called the photoelectric conversion layer. When there is a dense electron transport layer between the first conductive layer and the second conductive layer, the dense electron transport layer can be excluded from the photoelectric conversion layer.

[0034] The porous layer may include a porous electron transport layer or an insulating layer, or a porous electron transport layer and an insulating layer. It may also include a porous hole transport layer. Preferably, the porous electron transport layer is located on one side of the porous layer in the thickness direction (for example, the bottom side), and the insulating layer is located on the opposite side (for example, the top side). The porous layer may also include a second conductive layer.

[0035] Porous material is also called porous or mesoporous, and can be the same as or include the same as these. In this disclosure, porous material means a material that can contain light-absorbing parts (for example, perovskite compounds) in its voids (which can be expressed in various ways such as gaps, holes, or pores). A porous layer is preferably one in which a large number of pores are connected within the layer. Because it is porous, when a liquid (one with good wettability) is dropped onto a porous layer (one in which the pores are hollow), the liquid seeps into the porous layer. Furthermore, a porous layer refers to a layer formed entirely of porous materials, and if each layer, such as the photoelectric conversion layer 5, the hole transport layer 6, and the second conductive layer 7, is porous or contains porous parts, then these porous parts are also included in the term porous layer.

[0036] The porous electron transport layer (part of the photoelectric conversion layer 5) functions as an electron transport layer that transports electrons generated in the light absorption section to the electrodes. For example, titanium oxide, tin oxide, and aluminum oxide can be used as materials for the porous electron transport layer. Furthermore, any N-type inorganic oxide is preferable for the porous electron transport layer.

[0037] In this embodiment, the porous electron transport layer is a porous layer containing voids, and is occupied by metal oxides that constitute itself and voids which are the gaps between the metal oxides, and the voids of the porous electron transport layer are filled with a perovskite compound. The porous electron transport layer is a layer that can transport electrons generated by the perovskite compound. That is, as long as it is located on the electron transport side (or negative electrode side, similarly in this disclosure) of the perovskite compound of the solar cell, it can have an electron transport function. The porous electron transport layer may preferably be a mesoporous layer. Furthermore, it is even better if the porous electron transport layer is a mesoporous nanocrystalline layer.

[0038] The insulating layer (in this case, part of the photoelectric conversion layer 5) is made of a porous material. Examples of insulating layer materials include metal oxides containing titanium oxide, zirconium dioxide, and aluminum oxide, and oxides containing silicon dioxide. It should be noted that insulation does not need to completely prevent the movement of charge; depending on its thickness and structure, it is acceptable if it can suppress charge movement even if it cannot completely prevent it. Adding an insulating layer increases the distance between the first conductive layer (including the electron transport layer if present) and the second conductive layer (including the hole transport layer if present), suppressing physical contact between the materials on both sides and preventing the recombination of electrons and holes generated in the light absorption area. In other words, adding an insulating layer can improve the performance of the solar cell and contribute to achieving commercial-level performance. Therefore, the insulating layer exists between the first conductive layer (including the electron transport layer, if present) and the second conductive layer (including the hole transport layer, if present), contributing to increasing the distance between each side. As a result, if the solar cell is commercially available, verification is sufficient, and there is no need to verify the physical properties of the insulating performance.

[0039] The insulating layer is a porous layer containing voids, preferably having many voids with a size of 20 nm or more. Light-absorbing portions that absorb irradiated light are provided in the voids of the insulating layer. In this embodiment, the insulating layer is occupied by metal oxides that constitute itself and voids which are the gaps between the metal oxides, and the voids of the insulating layer are filled with a perovskite compound. The insulating layer also has voids with a size of less than 20 nm, and these small voids may also be considered as voids.

[0040] The thickness of the photoelectric conversion layer 5 is preferably 500 nm to 3 μm, and more preferably 400 nm to 600 nm. It is self-evident that the light-absorbing portion absorbs light and generates electrons and holes as long as the solar cell functions as a solar cell, and therefore does not require verification. As long as a material with light-absorbing properties is included, it can be assumed that the light-absorbing portion absorbs light and generates electrons and holes.

[0041] A light-absorbing region refers to a specific area (for example, a perovskite compound) that absorbs light, and this region can be collectively described as a light-absorbing layer. Here, a light-absorbing region can mean a specific area or part of the light-absorbing layer. Furthermore, a light-absorbing layer can mean a collection of discretely existing light-absorbing regions in a region with a certain thickness (which does not need to be constant) in a certain direction.

[0042] The perovskite compound contained in the light-absorbing portion is composed of a compound represented by the general formula: ABX3···(1). However, while the composition ratio of each is preferably 1:1:3, it is not necessarily 1:1:3, the content of each element may be adjusted as appropriate, and each constituent element does not need to be of only one type. As long as the light-absorbing portion has a photoelectric conversion function, the perovskite compound contained in the light-absorbing portion is exhibiting that photoelectric conversion function, and therefore, it is reasonable to assume that it is exhibiting that function even with the degree of freedom in composition as described in terms of composition ratio and type of constituent element. In general formula (1), A is an organic molecule (including an organic group or organic cation, as is the case in this disclosure) or an inorganic atom or molecule (including an inorganic group or inorganic cation, as is the case in this disclosure) or a combination thereof, B is a metal atom or molecule (including a metal cation, as is the case in this disclosure), and X is a halogen atom or molecule or a chalcogen atom or molecule (including a halogen anion or chalcogen anion, as is the case in this disclosure). In general formula (1), the three X's may be the same or different from each other. As long as a solar cell has a photoelectric conversion function, the perovskite compound contained in the light-absorbing part is exhibiting a photoelectric conversion function, and this should be taken into consideration. That is, if it can be confirmed that a compound is a perovskite compound, it is reasonable to consider it a perovskite compound that exhibits a photoelectric conversion function if it has A, B, and X. For example, it is sufficient if it is found to have an organic molecule, a metal atom, and a halogen atom. Furthermore, as long as a solar cell has a photoelectric conversion function, it can be confirmed that a compound is a perovskite compound if elements corresponding to A, B, and X are detected. For example, as organic molecules, molecules containing carbon, nitrogen, and hydrogen are suitable, and therefore, it is sufficient if carbon, nitrogen, hydrogen, a metal element, and a halogen or chalcogen are detected. Alternatively, a compound is a perovskite compound if it has A, B, and X. For example, it is sufficient if it is found to have an inorganic atom, a metal atom, and a halogen atom. Furthermore, the presence of a perovskite compound can be confirmed if elements A, B, and X are detected, as long as the solar cell has a photoelectric conversion function.For example, cesium or rubidium are preferred as inorganic atoms; therefore, it is sufficient if cesium or rubidium, a metallic element, and a halogen or chalcogen are detected. Furthermore, the fact that it is a perovskite compound is based on the premise that a solar cell has a crystalline structure as long as it has a photoelectric conversion function, and therefore confirmation of the presence of a crystalline structure is not required. The light-absorbing portion may contain substances other than the perovskite compound.

[0043] The light-absorbing portion may contain organic-inorganic hybrid compounds. An organic-inorganic hybrid compound refers to a compound containing both inorganic and organic materials. Perovskite compounds are also included in organic-inorganic hybrid compounds, and solar cells using perovskite compounds are also called organic-inorganic hybrid solar cells. "Organic" typically refers to materials composed of multiple carbon atoms. However, carbon materials such as graphite, graphene, carbon nanowires, carbon nanofibers, carbon nanotubes, and carbon or carbon black that function as electrodes are not specifically considered organic materials. In other words, organic refers to materials that, excluding the above-mentioned carbon materials such as graphite, have multiple carbon atoms as one of their constituent elements. "Inorganic" refers to materials that are not organic.

[0044] The light-absorbing portion may include quantum dots. A quantum dot is defined as a dot with a maximum width of 100 nm or less. The shape of the quantum dot is not particularly restricted and is not limited to a spherical three-dimensional shape (circular cross-sectional shape), as long as it satisfies the above maximum width. For example, it may have a polygonal cross-sectional shape, a rod-shaped three-dimensional shape, a branch-shaped three-dimensional shape, a three-dimensional shape with irregularities on the surface, or a combination thereof. The quantum dot is typically made of a semiconductor. A semiconductor is any material that can absorb light and may include at least the materials described below. The semiconductor includes, for example, at least one selected from the group consisting of group II-VI compounds, group III-V compounds, chalcogenides, and perovskite compounds. Note that group II-VI compounds mean compounds containing group II and group VI elements, and group III-V compounds mean compounds containing group III and group V elements. Furthermore, Group II elements include Group 2 and Group 12 elements, Group III elements include Group 3 and Group 13 elements, Group V elements include Group 5 and Group 15 elements, and Group VI elements may include Group 6 and Group 16 elements. Here, the group numbering of elements using Roman numerals is based on the old IUPAC or old CAS system, and the group numbering of elements using Arabic numerals is based on the current IUPAC system. Semiconductors include, for example, at least one selected from the group consisting of MgS, MgSe, MgTe, CaS, CaSe, CaTe, SrS, SrSe, SrTe, BaS, BaSe, BaTe, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, HgS, HgSe, HgTe, GaAs, GaP, InN, InAs, InP, and InSb.

[0045] Examples of organic molecules represented by A in general formula (1) include alkylamines, alkylammonium compounds, and nitrogen-containing heterocyclic compounds. In perovskite compound (1), the organic molecule represented by A may be only one type of organic molecule, or it may be two or more types of organic molecules.

[0046] 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.

[0047] Alkylammonium compounds are ionized compounds of the alkylamines mentioned above. Examples of alkylammonium compounds 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.

[0048] Examples of nitrogen-containing heterocyclic compounds include imidazole, azole, pyrrole, aziridine, azirine, azetidine, azeto, azole, imidazoline, and carbazole. Nitrogen-containing heterocyclic compounds may also be ionized. Phenethylammonium is preferred as an ionized nitrogen-containing heterocyclic compound.

[0049] 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.

[0050] In general formula (1), examples of metal atoms 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 perovskite compounds, the metal atom represented by B may be only one type of metal atom, or it may be two or more types of metal atoms. From the viewpoint of improving the light absorption and charge generation characteristics of perovskite compounds, lead atoms or tin atoms are preferred as the metal atom represented by B. From the viewpoint of reducing lead, tin atoms are preferred.

[0051] In general formula (1), examples of halogen atoms represented by X include fluorine, chlorine, bromine, and iodine atoms, while examples of chalcogen atoms include oxygen, sulfur, selenium, and tellurium atoms. In a perovskite compound, the halogen atom or chalcogen atom represented by X may be one or two or more. From the viewpoint of enabling the perovskite compound to utilize light in a broad wavelength range, iodine is preferred as the halogen atom represented by X. More specifically, it is preferable that at least one of the three Xs represents an iodine atom, and more preferably that all three Xs represent iodine atoms.

[0052] As the perovskite compound, compounds represented by the general formula "CH3NH3PbX3 (where X represents a halogen atom)" are preferred, and CH3NH3PbI3 is more preferred. By using a compound represented by the general formula "CH3NH3PbX3" (especially CH3NH3PbI3) as the perovskite compound, electrons and holes can be generated more efficiently in the perovskite compound, and as a result, the photoelectric conversion efficiency of the photoelectric conversion element 10 can be further improved.

[0053] A photoelectric conversion layer is a layer that converts light into electricity. It can include a porous layer and a light-absorbing layer, and refers to a layer located at least between the first conductive layer and the second conductive layer. The light-absorbing layer is often located between the first conductive layer and the second conductive layer, and if the light-absorbing layer is located only between the first and second conductive layers, then the photoelectric conversion layer is also located only between the first and second conductive layers. However, if the first and second conductive layers have a special shape, such as being porous, the light-absorbing layer may include a region encompassing the first and second conductive layers themselves. In such cases, the portion of the first and second conductive layers containing the light-absorbing layer can also be included in the photoelectric conversion layer. Even in that case, the photoelectric conversion layer is located at least between the first and second conductive layers. In other words, in all cases, a solar cell (photoelectric conversion element) is provided with a first conductive layer, a photoelectric conversion layer, and a second conductive layer in that order from the substrate, and this does not exclude the first and second conductive layers themselves from being included, nor does it exclude the presence of a photoelectric conversion layer in parts other than between the first and second conductive layers.

[0054] In this embodiment, the photoelectric conversion layer 5 is located on the dense electron transport layer 4 and extends over a wider area in the adjacent direction X than the dense electron transport layer 4. Specifically, the photoelectric conversion layer 5 is provided so as to straddle the island-like divisions of the first conductive layer 3, with a portion covering the substrate 2. In other words, the photoelectric conversion layer 5 is provided so as to extend from the first conductive layer 3 located at one end of the device region DR in the adjacent direction X (the left end in Figure 1) to the first conductive layer 3 located at the other end of the adjacent direction X (the right end in Figure 1).

[0055] The hole transport layer 6 has the function of transporting holes generated in the light absorption section and transporting the holes to the second conductive layer 7. Furthermore, it is preferable that the hole transport layer 6 also has the function of blocking electrons generated in the light absorption section. As long as the hole transport layer 6 is positioned between the light absorption section of the photoelectric conversion element 10 and the second conductive layer 7, it naturally has the function of hole transport, and as long as it is positioned on the hole transport side and the photoelectric conversion element 10 has the function of photoelectric conversion, it is not necessary to confirm the hole transport function. In other words, the hole transport layer 6 refers to the one positioned on the hole transport side of the light absorption section.

[0056] The hole transport layer 6 is preferably composed of a material with a band gap of 2 eV or more and an ionization potential smaller than 5.4 eV (shallow), and is preferably composed of an inorganic material. The thickness of the hole transport layer 6 can be, for example, 30 nm to 100 nm. Specific materials that constitute the hole transport layer 6 include oxides and sulfides such as copper oxide (Cu2O), zinc sulfide (ZnS), and nickel oxide. It may also be fine particles of oxides or sulfides. Organic materials may also be used. Furthermore, the hole transport layer 6 may inhibit electron transport (electron blocking). The hole transport layer 6 may also be accompanied by a separate electron blocking layer. Alternatively, there may be no hole transport layer 6, and instead there may be an electron blocking layer. The hole transport layer 6 is a porous layer, similar to the photoelectric conversion layer 5.

[0057] The hole transport layer 6 is provided in a region where a portion overlaps with the photoelectric conversion layer 5 in the adjacent direction X. Specifically, one end of the hole transport layer 6 in the adjacent direction X (the left end in Figure 1) does not reach the end of the photoelectric conversion layer 5, and a portion of the upper surface of the photoelectric conversion layer 5 is exposed. Furthermore, the hole transport layer 6 is provided in a region where a portion overlaps with the dense-quality electron transport layer 4 in the adjacent direction X, and is located above the dense-quality electron transport layer 4 with the photoelectric conversion layer 5 in between.

[0058] The second conductive layer 7 is a conductive material. It functions as an electrode for extracting the photovoltaic power of the photoelectric conversion element 10. It has the function of collecting holes photoexcited in the light absorption section, and is preferably formed of a porous carbon material.

[0059] As the second conductive layer 7, for example, a metal film with a work function of 5 eV or higher can be used. By having the second conductive layer 7 composed of a metal with a deep work function (5 eV or higher), it becomes easier to generate a band structure bend that smooths the flow of holes at the interface between the light-absorbing part or the layer on the light-absorbing part side and the second conductive layer 7. As the material for the second conductive layer 7, for example, metals such as Ni, Pt, and Pd can be used. The film thickness of the second conductive layer 7 is preferably around 50 nm to 150 nm. The second conductive layer 7 can be formed by, for example, a sputtering deposition method or a vacuum deposition method. In addition, conductive carbon materials such as graphite, graphene, carbon nanowires, carbon nanofibers, carbon nanotubes, and carbon black can be used. In principle, any material that is conductive is not excluded from application.

[0060] The light-absorbing portion described above contains a perovskite compound. In this embodiment, the hole transport layer 6 and the second conductive layer 7 also have light-absorbing portions. That is, the light-absorbing portions are arranged in the voids (which can be expressed in various ways, such as gaps, holes, or pores) of these layers. Preferably, it is desirable that the voids in the porous layer are filled with light-absorbing portions. As long as a solar cell has a photoelectric conversion function, it naturally includes light-absorbing portions as a component. The light-absorbing portion generates electrons and holes by absorbing light, the electrons generated in the light-absorbing portion move to the electron transport layer, and the holes generated in the light-absorbing portion move to the second conductive layer 7, where the charge is separated. As long as a solar cell has a photoelectric conversion function, it can be confirmed that electrons and holes are generated by absorbing light in the portion with the appropriate material, and it is not necessary to check the physical properties of the photoelectric conversion of the light-absorbing portion in order to confirm that it is a light-absorbing portion.

[0061] The second conductive layer 7 is provided in a region where a portion overlaps with the hole transport layer 6 in the adjacent direction X. Specifically, one end of the second conductive layer 7 in the adjacent direction X (the left end in Figure 1) does not reach the end of the photoelectric conversion layer 5, and a portion of the upper surface of the photoelectric conversion layer 5 is exposed. The other end of the second conductive layer 7 in the adjacent direction X (the right end in Figure 1) protrudes outside the photoelectric conversion layer 5 and the hole transport layer 6, covering the first conductive layer 3. In other words, the second conductive layer 7 has an overhanging portion 7a that protrudes further towards the non-device region HR than the photoelectric conversion layer 5 in the adjacent direction X.

[0062] In this embodiment, the barrier portion 8 is located in the non-device region HR, is provided on the first conductive layer 3, and is made of glass. In the photoelectric conversion element 10, as will be described later, when dropping the perovskite solution to form the light-absorbing portion, the barrier portion 8 functions as a dike around the photoelectric conversion layer 5, preventing the perovskite solution from flowing out of the device region DR. The barrier portion 8 only needs to function as a dike around the photoelectric conversion layer 5, and may be made of a material other than glass.

[0063] Figure 1 shows a configuration in which three photoelectric conversion elements 10 are provided. The protective wall 8 is provided between photoelectric conversion elements 10 that are aligned in the adjacent direction X, corresponding to each photoelectric conversion element 10.

[0064] When fabricating the photoelectric conversion module 1, a laminated substrate is created using general photolithography or screen printing processes, with the portions for each layer of the photoelectric conversion element 10 appropriately set. The protective wall portion 8 can be formed at any time after the formation of the first conductive layer 3, and the material can be appropriately selected according to the subsequent processes. When forming each layer of the photoelectric conversion element 10, high-temperature heat treatment is performed, so it is preferable to select a material with a melting temperature higher than the processing temperature at this stage.

[0065] After the above-described process, a first conductive layer 3, a dense electron transport layer 4, a photoelectric conversion layer 5, a hole transport layer 6, a second conductive layer 7, and a barrier layer 8 are formed on the substrate 2, followed by the step of dropping a perovskite solution 20 (see Figure 2). In this step, a perovskite precursor solution (perovskite solution 20) containing a perovskite compound is dropped from the top of the laminated substrate and fired. In this embodiment, the perovskite solution 20 was prepared by mixing and stirring methylamine iodide (1.14 M), lead iodide (1.2 M), 5-aminovaleric acid hydroiodide (0.06 M), and γ-butyrolactone (solvent).

[0066] The perovskite solution 20 dropped onto the laminated substrate penetrates the second conductive layer 7, the hole transport layer 6, and the photoelectric conversion layer 5. Subsequently, by firing, the perovskite solution 20 is evaporated, forming the perovskite compound, which is the light-absorbing portion, in the pores of the second conductive layer 7, the hole transport layer 6, and the photoelectric conversion layer 5.

[0067] As described above, the process of dropping a perovskite solution is carried out when manufacturing the photoelectric conversion module 1. Concerns regarding this step will be explained with reference to the comparative example shown in Figure 2.

[0068] Figure 2 is a schematic cross-sectional view showing a photoelectric conversion module of a comparative example.

[0069] Figure 2 shows a comparative example of a photoelectric conversion module (comparative module 100). In comparative module 100, the difference from the structure shown in Figure 1 is that protective barriers 8 are provided only at both ends of the base body 2, and protective barriers 8 are not provided between photoelectric conversion elements 10 that are arranged in the adjacent direction X.

[0070] The perovskite solution 20 is dropped from above each photoelectric conversion element 10. If a barrier 8 is not provided between the photoelectric conversion elements 10, the perovskite solution 20 will spread disorderly, as indicated by arrows F1 to F5. As a result, variations occur in the amount of perovskite solution 20 on each photoelectric conversion element 10, leading to a decrease in conversion efficiency and inconsistencies.

[0071] In a photoelectric conversion module 1 having multiple photoelectric conversion elements 10, there is a problem that if there is a photoelectric conversion element 10 with low conversion efficiency, the conversion efficiency of all photoelectric conversion elements 10 will be dragged down by it.

[0072] In contrast, in the photoelectric conversion module 1 according to this embodiment, as shown in Figure 1, the photoelectric conversion elements 10 are separated from each other by a barrier section 8. By providing a barrier section 8 for each photoelectric conversion element 10 in this way, it is possible to prevent the dropped perovskite solution 20 from flowing out into the area of ​​the adjacent photoelectric conversion element 10. As a result, the amount of solution dropped can be controlled to be the desired amount for each photoelectric conversion element 10, and variations in the amount of solution dropped can be suppressed, thereby stabilizing the conversion efficiency.

[0073] Furthermore, since the protective wall portion 8 is provided in a non-device region HR that does not overlap with the photoelectric conversion element 10, it is less susceptible to manufacturing process constraints on the photoelectric conversion element 10, and there is more room to select the material of the protective wall portion 8.

[0074] Furthermore, by using glass as the material for the barrier wall 8, the dropped perovskite solution 20 can be more reliably blocked by the barrier wall 8.

[0075] (Second Embodiment) Next, the photoelectric conversion module 1 according to the second embodiment of this disclosure will be described with reference to the drawings. Note that the structure of the photoelectric conversion module 1 according to the second embodiment is substantially the same as that of the first embodiment shown in Figure 1; therefore, common parts are denoted by the same reference numerals and their descriptions are omitted.

[0076] Figure 3 is a schematic cross-sectional view showing a photoelectric conversion module according to a second embodiment of the present disclosure.

[0077] The second embodiment differs from the first embodiment in the area over which the protective barrier 8 is provided. Specifically, in this embodiment, the protective barrier 8 straddles the boundary between the device region DR and the non-device region HR and is provided overlapping the protruding portion 7a of the second conductive layer 7.

[0078] In this way, since a portion of the protective wall 8 is formed overlapping the device region DR, the space required in the non-device region HR for providing the protective wall 8 can be reduced, allowing for denser integration of the photoelectric conversion elements 10. Furthermore, since the protective wall 8 overlaps the protruding portion 7a and does not overlap the photoelectric conversion layer 5, the dropped solution can be smoothly penetrated into the photoelectric conversion layer 5 directly below it.

[0079] (Third embodiment) Next, the photoelectric conversion module 1 according to the third embodiment of this disclosure will be described with reference to the drawings. The structure of the photoelectric conversion module 1 according to the third embodiment is substantially the same as that of the first and second embodiments shown in Figures 1 and 3, so the same reference numerals are used for common parts and their descriptions are omitted.

[0080] Figure 4 is a schematic cross-sectional view showing a photoelectric conversion module according to the third embodiment of this disclosure.

[0081] The third embodiment differs from the second embodiment in the extent to which the barrier portion 8 is provided. Specifically, in this embodiment, the barrier portion 8 is provided at the end of the second conductive layer 7 in the adjacent direction X, overlapping the protruding portion 7a. In other words, the barrier portion 8 is provided only on the end of the second conductive layer 7 and not on the first conductive layer 3 outside the second conductive layer 7. However, for photoelectric conversion elements 10 located at the ends of the photoelectric conversion elements 10 arranged side by side, the barrier portion 8 may be provided on the first conductive layer 3 so as to surround the outside. By providing the barrier portion 8 on the second conductive layer 7, as shown by arrow F6, the perovskite solution 20 flowing along the surface of the second conductive layer 7 can be blocked by the barrier portion 8, preventing it from flowing out to the area of ​​the adjacent photoelectric conversion element 10.

[0082] In this disclosure, the first conductive layer side or the light-receiving surface side is described as the electron transport side, and the second conductive layer side or the back surface side is described as the hole transport side. However, this disclosure can also be applied when the conductivity types are reversed, i.e., when the first conductive layer side or the light-receiving surface side is the hole transport side and the second conductive layer side or the back surface side is the electron transport side. In that case, the terms "hole" and "electron" can be reversed as appropriate when applying the disclosure.

[0083] Furthermore, the embodiments disclosed herein are illustrative in all respects and do not constitute a limiting interpretation. Accordingly, the technical scope of this disclosure is not to be interpreted solely by the embodiments described above, but is defined based on the claims. This includes all modifications within the meaning and scope of equivalents to the claims.

[0084] (Note) (Aspect 1) A photoelectric conversion module having multiple photoelectric conversion elements, The aforementioned photoelectric conversion element is provided with, in order from the substrate, a first conductive layer, a photoelectric conversion layer, and a second conductive layer. The photoelectric conversion layer comprises a perovskite compound formed in the voids of the porous layer. A protective wall is formed so as to surround the photoelectric conversion layer, spaced apart from it. The protective barrier is provided for each of the photoelectric conversion elements. A photoelectric conversion module characterized by the following.

[0085] (Aspect 2) A photoelectric conversion module according to Embodiment 1, Non-device regions are provided between the device regions corresponding to the aforementioned photoelectric conversion elements. The protective wall portion is provided in the non-device area. A photoelectric conversion module characterized by the following.

[0086] (Aspect 3) A photoelectric conversion module according to Embodiment 1, Non-device regions are provided between the device regions corresponding to the aforementioned photoelectric conversion elements. The protective wall portion is provided across the boundary between the device area and the non-device area. A photoelectric conversion module characterized by the following.

[0087] (Aspect 4) A photoelectric conversion module according to embodiment 3, The second conductive layer has a protruding portion that extends further toward the non-device region than the photoelectric conversion layer in the adjacent direction in which adjacent photoelectric conversion cells are lined up. The aforementioned protective wall portion is provided overlapping the aforementioned protruding portion. A photoelectric conversion module characterized by the following.

[0088] (Appendix 5) A photoelectric conversion module according to Embodiment 1, The protective wall portion is provided overlapping the edges of the second conductive layer in the adjacent direction where adjacent photoelectric conversion cells are lined up. A photoelectric conversion module characterized by the following.

[0089] (Aspect 6) A photoelectric conversion module according to embodiment 5, The second conductive layer has a protruding portion that, in the adjacent direction, protrudes toward the non-device region side compared to the photoelectric conversion layer, The aforementioned protective wall portion is provided overlapping the aforementioned protruding portion. A photoelectric conversion module characterized by the following.

[0090] (Aspect 7) A photoelectric conversion module according to any one of embodiments 1 to 6, The aforementioned protective wall is made of glass. A photoelectric conversion module characterized by the following.

[0091] (Pattern 8) A photoelectric conversion module according to any one of embodiments 1 to 6, The porous layer includes a porous electron transport layer and a porous insulating layer. A photoelectric conversion module characterized by the following.

[0092] (Aspect 9) A photoelectric conversion module having multiple photoelectric conversion elements, The aforementioned photoelectric conversion element is provided with, in order from the substrate, a first conductive layer, a photoelectric conversion layer, and a second conductive layer. The photoelectric conversion layer comprises a perovskite compound formed in the voids of the porous layer. A protective wall portion is formed on the outside of the photoelectric conversion layer when viewed in cross-section. The protective barrier is provided between the photoelectric conversion elements. A photoelectric conversion module characterized by the following.

[0093] (Aspect 10) A method for manufacturing a photoelectric conversion module having multiple photoelectric conversion elements, The photoelectric conversion element includes the step of providing a first conductive layer, a photoelectric conversion layer, and a second conductive layer in order from the substrate, The photoelectric conversion layer comprises a perovskite compound formed in the voids of the porous layer. The step includes providing a protective wall surrounding the photoelectric conversion layer for each of the photoelectric conversion elements. A method for manufacturing a photoelectric conversion module characterized by the following. [Explanation of Symbols]

[0094] 1. Photoelectric conversion module 2 Base 3. First conductive layer 4 Dense electron transport layer 5 Photoelectric conversion layer 6. Hole transport layer 7. Second conductive layer 7a Extrusion part 8. Barrier section 10 Photoelectric conversion element 20 Perovskite solution DR device area HR Non-Device Area X adjacent direction

Claims

1. A photoelectric conversion module having multiple photoelectric conversion elements, The aforementioned photoelectric conversion element is provided with, in order from the substrate, a first conductive layer, a photoelectric conversion layer, and a second conductive layer. The photoelectric conversion layer comprises a perovskite compound formed in the voids of the porous layer. A protective wall is formed so as to surround the photoelectric conversion layer. The protective barrier is provided for each of the photoelectric conversion elements. A photoelectric conversion module characterized by the following.

2. A photoelectric conversion module according to claim 1, Non-device regions are provided between the device regions corresponding to the aforementioned photoelectric conversion elements. The protective wall portion is provided in the non-device area. A photoelectric conversion module characterized by the following.

3. A photoelectric conversion module according to claim 1, Non-device regions are provided between the device regions corresponding to the aforementioned photoelectric conversion elements. The protective wall portion is provided across the boundary between the device area and the non-device area. A photoelectric conversion module characterized by the following.

4. A photoelectric conversion module according to claim 3, The second conductive layer has a protruding portion that extends further toward the non-device region than the photoelectric conversion layer in the adjacent direction in which adjacent photoelectric conversion cells are lined up. The aforementioned protective wall portion is provided overlapping the aforementioned protruding portion. A photoelectric conversion module characterized by the following.

5. A photoelectric conversion module according to claim 1, The protective wall portion is provided overlapping the end of the second conductive layer in the adjacent direction where adjacent photoelectric conversion cells are lined up. A photoelectric conversion module characterized by the following.

6. A photoelectric conversion module according to claim 5, The second conductive layer has a protruding portion that, in the adjacent direction, protrudes toward the non-device region side compared to the photoelectric conversion layer, The aforementioned protective wall portion is provided overlapping the aforementioned protruding portion. A photoelectric conversion module characterized by the following.

7. A photoelectric conversion module according to claim 1, The aforementioned protective wall is made of glass. A photoelectric conversion module characterized by the following.

8. A photoelectric conversion module according to claim 1, The porous layer includes a porous electron transport layer and a porous insulating layer. A photoelectric conversion module characterized by the following.

9. A photoelectric conversion module having multiple photoelectric conversion elements, The aforementioned photoelectric conversion element is provided with, in order from the substrate, a first conductive layer, a photoelectric conversion layer, and a second conductive layer. The photoelectric conversion layer comprises a perovskite compound formed in the voids of the porous layer. A protective wall portion is formed on the outside of the photoelectric conversion layer when viewed in cross-section. The protective barrier is provided between the photoelectric conversion elements. A photoelectric conversion module characterized by the following.

10. A method for manufacturing a photoelectric conversion module having multiple photoelectric conversion elements, The photoelectric conversion element includes the step of providing a first conductive layer, a photoelectric conversion layer, and a second conductive layer in order from the substrate, The photoelectric conversion layer comprises a perovskite compound formed in the voids of the porous layer. The step includes providing a protective wall surrounding the photoelectric conversion layer for each of the photoelectric conversion elements. A method for manufacturing a photoelectric conversion module characterized by the following.

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