Solar battery module and manufacturing method for the same

Abstract

To provide a solar battery cell in which the permeability of a perovskite solution is improved.SOLUTION: A solar battery module 1 includes a plurality of solar battery cells 10. The solar battery cell 10 has a transparent electrode layer 3, a porous electron transport layer 5, an insulating layer 6, and a second conductive layer 7 provided in this order from a base body 2. The porous electron transport layer 5 and the insulating layer 6 include a porous structure having pores containing a perovskite compound. A gap part 10a for separating the solar battery cells 10 is provided between the insulating layer 6 in any one solar battery cell 10 and the insulating layer 6 of the adjacent solar battery cell 10. In the gap part 10a, a mediation part 9 containing a perovskite compound is provided.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] In recent years, solar cells (solar cell modules) have become increasingly popular as a way to utilize renewable energy. Solar cells using inorganic photoelectric conversion elements (e.g., silicon-based solar cells, CIGS-based solar cells, and CdTe-based solar cells) are widely used, but solar cells using organic photoelectric conversion elements (e.g., organic thin-film solar cells, dye-sensitized solar cells, and perovskite solar cells) are also being considered.

[0003] A solar cell module is configured to have a plurality of solar cells, for example, a plurality of strip-shaped solar cells arranged and connected in series. For solar cell modules, methods have been proposed for improving the connection between adjacent solar cells (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-168842 Summary of the Invention [Problem to be solved by the invention]

[0005] A conventional solar cell module is a multilayer structure in which at least two solar cells are deposited on a substrate having a downweb direction and a crossweb direction, the multilayer structure including: a first electrode strip disposed on the substrate, extending along the crossweb direction, and forming a layer of a first conductive material; an insulating strip disposed on the layer of first conductive material, defining a connection region and an active region, and formed of an insulating material, extending along the downweb direction; a functional stack disposed on the layer of first conductive material and within the active region, including a layer of photoactive semiconductor material coated over the entire web; a second electrode strip disposed within the functional stack and the active region, extending in the crossweb direction, and aligned with the first electrode strip to form a solar cell; and an electrical connection pattern extending over the insulating strip for electrically connecting the second electrode strip of any solar cell to the first electrode strip of an adjacent solar cell within the connection region.

[0006] In conventional solar cell modules, laser ablation or mechanical scribing is used to form an insulating wire that passes through a layer of conductive material (second electrode strip) that coats the entire web and the second intermediate layer. However, due to the difficulty of removing the second electrode strip and the second intermediate layer while leaving the first electrode strip, sufficient separation is not possible, and current leaks between the cells, reducing the power generation efficiency of the solar cell module.

[0007] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a solar cell module that can inhibit current leakage and achieve high efficiency of solar cells, and a method for manufacturing the same. [Means for solving the problem]

[0008] The solar cell module according to the present disclosure is a solar cell module having a plurality of solar cells, each of which is provided with, in order from a base, a first conductive layer, a photoelectric conversion layer, and a second conductive layer, the photoelectric conversion layer having a light absorbing portion and a porous layer, a gap portion between the porous layer in any one of the solar cells and the porous layer in an adjacent solar cell, and the gap portion is provided with an intervening portion including a light absorbing portion.

[0009] In the solar cell module according to the present disclosure, the light absorbing portion may include a perovskite compound.

[0010] In the solar cell module according to the present disclosure, a configuration may be adopted in which a plurality of the intervening portions are provided and dispersed in an island shape within the gap portion.

[0011] In the solar cell module according to the present disclosure, the porous layer may be configured to protrude further toward the gap than the second conductive layer in the direction in which the adjacent solar cells are arranged.

[0012] In the solar cell module according to the present disclosure, the porous layer may include an insulating layer, and the insulating layer may have zirconium oxide.

[0013] The method for manufacturing a solar cell module according to the present disclosure is a method for manufacturing a solar cell module having a plurality of solar cells, and includes the steps of providing, in the solar cell, a first conductive layer, a photoelectric conversion layer, and a second conductive layer in that order from a base, the photoelectric conversion layer has a light absorbing portion and a porous layer, and a gap portion is provided between the porous layer in any one of the solar cells and the porous layer in an adjacent solar cell, and the gap portion is provided with an intervening portion including a light absorbing portion.

[0014] The method for manufacturing a solar cell module according to the present disclosure may include a step of impregnating the voids of the porous layer with a perovskite compound and forming the interposed portion. [Effects of the Invention]

[0015] According to the present disclosure, the intervening portion provided in the gap portion acts as an insulator between the solar cells, inhibiting current leakage and enabling high efficiency of the solar cells. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic cross-sectional view showing a solar cell according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic cross-sectional view showing a step of dripping a perovskite solution in a method for manufacturing a solar cell. [Figure 3] This is a photograph taken from above near the gap. [Figure 4] This is an enlarged photograph of Figure 3. DETAILED DESCRIPTION OF THE INVENTION

[0017] Solar cell modules according to embodiments of the present disclosure will now be described with reference to the drawings.

[0018] FIG. 1 is a schematic cross-sectional view showing a solar cell module according to an embodiment of the present disclosure.

[0019] A solar cell 10 according to the embodiment of the present disclosure includes a substrate 2 on which a transparent electrode layer 3 (an example of a first conductive layer), a dense electron transport layer 4, a porous electron transport layer 5 (an example of an electron transport layer), an insulating layer 6, and a second conductive layer 7 are stacked. A plurality of solar cells 10 are arranged side by side on the substrate 2, and the solar cell module 1 is configured by connecting the plurality of solar cells 10 in series. For ease of explanation, the direction in which the plurality of solar cells 10 are arranged in series may be referred to as the adjacent direction X (the direction of the double-headed arrow X in FIG. 1). The following description focuses on one of the plurality of solar cells 10 (the solar cell 10 on the right side in FIG. 1), and the remaining solar cells 10 (such as the solar cell 10 on the left side in FIG. 1) may be referred to as adjacent solar cells 10.

[0020] The base 2 is the base of the solar cell 10 and may be the same as or include the substrate or base material. It may be hard and highly rigid, or it may be flexible or have low rigidity. The base 2 may be, for example, flat or film-like in shape. When light is irradiated (light is incident) on the surface of the solar cell 10 facing the base 2 (the underside of the base 2 in FIG. 1), i.e., when the side facing the base 2 is the light-receiving surface, the base 2 is preferably transparent. In this case, examples of materials for the base 2 include glass and heat-resistant transparent resins. When light is irradiated from the opposite side, the base 2 may be opaque. While "transparent" means that light is transmitted through the base 2, this does not exclude materials that reflect or absorb light even slightly. It is sufficient for the base 2 to transmit light appropriately, and this can be considered synonymous with being located on the light-receiving surface side of the solar cell (including the portion where light is incident, as in the present disclosure). Therefore, a material can be considered transparent simply by being located on at least the light-receiving surface side of the solar cell.

[0021] The first conductive layer, i.e., the transparent electrode layer 3, which is an example of the first conductive layer in this embodiment, is a conductive member. The first conductive layer 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 photovoltaic power from the solar cell 10. The transparent electrode layer 3 is divided into multiple island-like layers spaced apart in the adjoining direction X. The transparent electrode layer 3 is formed of a transparent conductive material, 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 (antimony-doped tin oxide), or a conductive transparent polymer. Note that the chemical formulas are representative examples and may be compound names (as in the present disclosure). Furthermore, while it is desirable for the composition ratio of the chemical formula to be stoichiometric, it does not necessarily have to be stoichiometric (as in the present disclosure). The transparent electrode layer 3 may be configured such that a conductive metal such as silver or thin wires thereof are formed on an oxide film of a conductive transparent material or the like. The term "film" does not specify thickness or width, and includes patterned or island-shaped films and films with portions of different thicknesses. Preferably, the film has a substantially constant thickness. Unless otherwise specified, "approximately" or "approximately" refers to the range of manufacturing error, and preferably indicates that a variation of plus or minus 15% of the numerical value is allowed.

[0022] The dense electron transport layer 4 is a layer capable of transporting electrons generated in the light-absorbing portion (e.g., a perovskite compound). The dense electron transport layer 4 naturally has this function as long as the solar cell has a photoelectric conversion function, and it can be considered synonymous with being disposed on the electron transport side of the light-absorbing portion of the solar cell. Therefore, as long as it is disposed at least on the electron transport side of the light-absorbing portion, it can be said to have an electron transport function. The dense electron transport layer 4 preferably has a function of blocking hole transport. The dense electron transport layer 4 is dense. Details of the dense material will be described below, but it is preferable that the layer has few or no pores. Furthermore, it is preferable that most of these pores are independent and unconnected. Therefore, even if a liquid is dropped onto the dense layer, it can function as a layer that hardly penetrates into the dense layer. In this embodiment, the dense electron transport layer 4 is formed of titanium oxide or tin oxide. Furthermore, the dense electron transport layer 4 is provided on the transparent electrode layer 3 and is not present on the substrate 2.

[0023] The term "layer" does not specify thickness or width, and includes a pattern or island shape, or a layer having portions of different thickness. A layer is preferably a member having a substantially constant thickness.

[0024] Dense matter may also be called compact, compact substance, etc., and may be the same as or include these.

[0025] Furthermore, a dense material refers to a material having extremely small voids. That is, in the present disclosure, a dense material refers to a material that can be observed such that no light-absorbing portion (in this embodiment, as an example, a perovskite compound, hereinafter referred to as a perovskite compound) is present on one side (for example, the lower side) of the dense material in the thickness direction. That is, even if a perovskite compound is present on the upper side of the dense material, it is possible to ensure that it does not penetrate to the lower side of the dense material. Preferably, a dense material refers to a material having extremely small voids. Preferably, a dense material refers to a material in which the maximum void width is less than 5 nm. Preferably, a dense material is one that suppresses the penetration of the perovskite compound, and is capable of being free of the perovskite compound on one side of the dense material in the thickness direction. More preferably, a dense material refers to a material that cannot contain a perovskite compound in the voids or does not have a portion where the perovskite compound is continuously present throughout the thickness of the dense material. That is, when a dense material cannot be confirmed by the maximum width of the voids it has, it is sufficient if observation by SEM or EDX reveals that there are no portions where the perovskite compound exists throughout the layer thickness. In the present disclosure, unless otherwise stated, SEM observation should be performed on a 400 nm wide cross-sectional SEM (or EDX) image and confirmed. For example, if observation by SEM or EDX of a single 400 nm wide cross-section reveals no portions where the perovskite compound exists throughout the layer thickness, the layer can be said to be dense.

[0026] The porous layer refers to a layer that is porous. Porous is also referred to as porous or mesoporous, and can be the same as or can include these. Furthermore, porous refers to a layer that can contain a light-absorbing portion (perovskite compound in this embodiment) in its voids (which can be variously expressed as gaps, holes, or holes). The porous layer includes a porous electron transport layer or an insulating layer, or a porous electron transport layer and an insulating layer. Preferably, the porous electron transport layer is disposed on one side (for example, the lower side) of the porous layer in the thickness direction, and an insulating layer is disposed on the opposite side (for example, the upper side). The porous layer can also be included in the second conductive layer.

[0027] The porous electron transport layer 5 functions as an electron transport layer that transports electrons generated in the light absorbing section to the electrode. Examples of materials that can be used for the porous electron transport layer 5 include titanium oxide, tin oxide, and aluminum oxide. Furthermore, an n-type inorganic oxide is suitable for the porous electron transport layer 5. As already described in detail, a porous layer preferably has numerous pores that are interconnected. Because of its porosity, when a liquid (with good wettability) is dropped onto a porous layer (with hollow pores), the liquid can permeate the porous layer. Like the dense electron transport layer 4, the porous electron transport layer 5 is a layer that can transport electrons generated in the perovskite compound. Naturally, the porous electron transport layer 5 also functions as a solar cell. That is, as long as it is disposed on the electron transport side (or negative electrode side, as in the present disclosure) of the perovskite compound of the solar cell, it can be considered to have the electron transport function. The porous electron transport layer 5 may preferably be a mesoporous layer. Furthermore, it is even more preferable if the porous electron transport layer 5 is a mesoporous nanocrystalline layer.

[0028] In this embodiment, the porous electron transport layer 5 is provided on the dense electron transport layer 4, and has a smaller area in the adjoining direction X than the dense electron transport layer 4. Therefore, there is a region on the upper surface of the dense electron transport layer 4 that is not covered with the porous electron transport layer 5. The porous electron transport layer 5 is also disposed near the end of the dense electron transport layer 4 in the adjoining direction X (the right end in FIG. 1 ).

[0029] In this embodiment, the dense electron transport layer 4 is disposed on the transparent electrode layer 3 with the same width (width in the adjacent direction X in FIG. 1), but the width does not necessarily have to be the same. At the end in the adjacent direction X (left end in FIG. 1), the transparent electrode layer 3 may be formed so that a part of the transparent electrode layer 3 is not covered with the dense electron transport layer 4 and is exposed. This improves the electrical connection between the transparent electrode layer 3 of the solar cell (the solar cell on the right in FIG. 1) and the second conductive layer 7 of the adjacent solar cell (the solar cell on the left in FIG. 1).

[0030] The insulating layer 6 is made of a porous material. Examples of materials for the insulating layer 6 include metal oxides, such as titanium oxide, zirconium dioxide, and aluminum oxide, and oxides, such as silicon dioxide. Note that insulation does not necessarily have to completely prevent charge transfer; it is acceptable for the thickness and structure of the insulating layer to suppress, but not completely prevent, charge transfer. 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), thereby reducing physical contact between the materials on both sides and suppressing the recombination of electrons and holes generated in the light-absorbing region. In other words, adding an insulating layer improves the performance of solar cells and contributes to achieving commercialized 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) and contributes to increasing the distance between the two sides. As a result, it is sufficient to confirm the physical properties of the insulating layer if the solar cell is commercialized; it is not necessary to verify the insulating performance. The insulating layer 6 is a porous layer containing voids, and preferably has a large number of voids with a size of 20 nm or more. In other words, the insulating layer 6 is occupied by, for example, the metal oxide that constitutes the insulating layer 6 itself and the voids that are the gaps between the metal oxides. The insulating layer 6 also has voids with a size of less than 20 nm, and the porosity is set to include these small voids. Furthermore, light absorbing portions that absorb irradiated light are provided in the voids of the insulating layer 6.

[0031] In this embodiment, the insulating layer 6 is provided on the porous electron transport layer 5 and has a wider area in the adjacent direction X than the porous electron transport layer 5. Specifically, one end of the insulating layer 6 in the adjacent direction X (the left end in FIG. 1 ) covers part of the upper surface of the dense electron transport layer 4, and the other end of the insulating layer 6 in the adjacent direction X (the right end in FIG. 1 ) protrudes outside the dense electron transport layer 4 and covers the side surfaces of the transparent electrode layer 3 and the dense electron transport layer 4. The other end of the insulating layer 6 in the adjacent direction X does not reach the transparent electrode layer 3 and the dense electron transport layer 4 of the adjacent solar cell 10 and is separated therefrom.

[0032] The second conductive layer 7 is a conductive member. It functions as an electrode for extracting photovoltaic power from the solar cell 10. It has the function of collecting photoexcited holes in the light absorbing portion and is preferably formed of a porous carbon material. The second conductive layer 7 is provided in a range where it partially overlaps with the insulating 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 FIG. 1 ) does not reach the end of the insulating layer 6, so that a portion of the upper surface of the insulating layer 6 (the insulating layer upper surface 6a) is exposed. The other end of the second conductive layer 7 in the adjacent direction X (the right end in FIG. 1 ) extends outside the insulating layer 6 and reaches the transparent electrode layer 3 and dense electron transport layer 4 of the adjacent solar cell 10. In other words, the end of the second conductive layer 7 contacts the dense electron transport layer 4 of the adjacent solar cell 10, so that the adjacent solar cell 10 are electrically connected to each other.

[0033] The second conductive layer 7 can be, for example, a metal film with a work function of 5 eV or more. By using a metal with a high work function (5 eV or more) for the second conductive layer 7, a bending of the band structure that allows holes to flow smoothly is easily generated at the interface between the second conductive layer and the light absorbing layer or the light absorbing section or the layer on the light absorbing section side. The second conductive layer 7 can be made of, for example, metals such as Ni, Pt, and Pd. The thickness of the second conductive layer 7 is preferably about 50 nm to 150 nm. The second conductive layer 7 can be formed by, for example, a sputtering method or a vacuum deposition method. Alternatively, conductive carbon materials such as graphite, graphene, carbon nanowires, carbon nanofibers, carbon nanotubes, and carbon black can be used. Basically, any conductive material can be used.

[0034] The light-absorbing portion described above contains a perovskite compound. In this embodiment, the porous electron transport layer 5, the insulating layer 6, and the second conductive layer 7 also contain light-absorbing portions. That is, the light-absorbing portions are disposed in the voids (which can also be variously expressed as gaps, holes, or cavities) of these layers. Preferably, these layers are filled with light-absorbing portions. The voids in the porous electron transport layer 5, the insulating layer 6, and the second conductive layer 7 are desirably filled with light-absorbing portions. As long as a solar cell has a photoelectric conversion function, it naturally includes a light-absorbing portion 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 charges are separated. As long as the solar cell has a photoelectric conversion function, it can be assumed that electrons and holes are generated by absorbing light in a portion containing an appropriate material. Therefore, it is not necessary to confirm the photoelectric conversion properties of the light-absorbing portion to confirm that it is a light-absorbing portion.

[0035] The light-absorbing portion can refer to any region that absorbs light (e.g., a perovskite compound is included). If there are other light-absorbing portions in addition to the light-absorbing portion shown, they can be collectively referred to as a light-absorbing layer. In other words, the light-absorbing portion can refer to any region in the light-absorbing layer. Furthermore, the light-absorbing layer can refer to a collection of light-absorbing portions that exist discretely or continuously in a region that has a thickness (similar to the definition of "layer," which does not need to be constant, for example) and is mainly in a certain direction.

[0036] The perovskite compound contained in the light-absorbing portion is composed of a compound represented by the general formula: ABX3 (1). While the composition ratio of each element is preferably 1:1:3, it does not necessarily have to be 1:1:3. The content ratio of each element may vary as appropriate, and each element does not necessarily have to be a single type. As long as the light-absorbing portion has a photoelectric conversion function, the perovskite compound contained in the light-absorbing portion exhibits the photoelectric conversion function. Therefore, even if there is a degree of freedom in the composition as described above regarding the composition ratio and the type of constituent elements, it is reasonable to consider that the function is exhibited. In general formula (1), A is an organic molecule (including an organic group or an organic cation, as defined herein), an inorganic atom or molecule (including an inorganic group or an inorganic cation, as defined herein), or a combination thereof; B is a metal atom or molecule (including a metal cation, as defined herein); and X is a halogen atom or molecule or a chalcogen atom or molecule (including a halogen anion or a chalcogen anion, as defined herein). In general formula (1), the three Xs may be the same or different. As long as a solar cell has a photoelectric conversion function, the perovskite compound contained in the light absorbing portion exhibits the photoelectric conversion function, and this should be taken into consideration. That is, if it is confirmed that a compound is a perovskite compound, it is reasonable to consider it a perovskite compound exhibiting a photoelectric conversion function. For example, it is sufficient to know that it contains organic molecules, metal atoms, and halogen atoms. Furthermore, as long as a solar cell has a photoelectric conversion function, it is sufficient to confirm that it is a perovskite compound if elements corresponding to A, B, and X are detected. For example, molecules containing carbon, nitrogen, and hydrogen are suitable as organic molecules, and therefore it is sufficient to detect carbon, nitrogen, hydrogen, a metal element, and a halogen or chalcogen. Alternatively, it is sufficient to confirm that a compound is a perovskite compound if it contains A, B, and X. For example, it is sufficient to confirm that it contains inorganic atoms, metal atoms, and halogen atoms. Furthermore, the perovskite compound can be confirmed if elements corresponding to A, B, and X are detected, so long as the solar cell has a photoelectric conversion function.For example, cesium or rubidium is suitable as the inorganic atom, and therefore, it is sufficient to detect cesium or rubidium, a metal element, and a halogen or chalcogen. Furthermore, since it is a natural consequence that a solar cell has a crystalline structure as long as it has a photoelectric conversion function, it is not necessary to confirm that the compound is a perovskite compound. This does not exclude the inclusion of compounds other than perovskite compounds in the light-absorbing portion.

[0037] The light absorbing portion may contain an organic-inorganic hybrid compound. An organic-inorganic hybrid compound refers to a compound containing an inorganic material and an organic material. Organic-inorganic hybrid compounds also include perovskite compounds, and solar cells using perovskite compounds are also called organic-inorganic hybrid solar cells. "Organic" typically refers to a material composed of multiple carbon atoms. Note that graphite, graphene, carbon nanowires, carbon nanofibers, carbon nanotubes, and carbon materials such as carbon and carbon black that function as electrodes are not considered to be organic materials. In other words, organic refers to a material that contains multiple carbon atoms as one of its constituent elements, excluding the above-mentioned carbon materials such as graphite. "Inorganic" refers to a material that is not organic.

[0038] The light-absorbing portion may contain quantum dots. Quantum dots refer to dots with a maximum width of 100 nm or less. The shape of the quantum dots is not particularly limited as long as it satisfies the above-mentioned maximum width, and is not limited to a spherical three-dimensional shape (circular cross-sectional shape). For example, they may have a polygonal cross-sectional shape, a rod-like three-dimensional shape, a branch-like three-dimensional shape, a three-dimensional shape with an uneven surface, or a combination thereof. The quantum dots are typically made of a semiconductor. The semiconductor may be any material capable of absorbing light and may include at least the materials described below. The semiconductor may include, for example, at least one selected from the group consisting of II-VI group compounds, III-V group compounds, chalcogenides, and perovskite compounds. The II-VI group compounds refer to compounds containing II and VI elements, and the III-V group compounds refer to compounds containing III and V elements. Furthermore, Group II elements may include Group 2 and Group 12 elements, Group III elements may include Group 3 and Group 13 elements, Group V elements may include Group 5 and Group 15 elements, and Group VI elements may include Group 6 and Group 16 elements. Here, the numbering of element groups using Roman numerals is based on the old IUPAC system or the old CAS system, and the numbering of element groups using Arabic numerals is based on the current IUPAC system. The semiconductor may 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.

[0039] In the general formula (1), examples of the organic molecule represented by A include alkylamine, alkylammonium, and nitrogen-containing heterocyclic compounds. In the perovskite compound (1), the organic molecule represented by A may be only one type of organic molecule, or may be two or more types of organic molecules.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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 properties and charge generation properties of the perovskite compound, 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.

[0045] 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. The halogen atom represented by X is preferably an iodine atom, from the viewpoint of enabling the perovskite compound to utilize light in a wide wavelength range. Specifically, of the three Xs, it is preferable that at least one X represents an iodine atom, and it is more preferable that all three Xs represent iodine atoms.

[0046] The perovskite compound is preferably a compound represented by the general formula "CH3NH3PbX3 (wherein X represents a halogen atom)", and more preferably CH3NH3PbI3. By using a compound represented by the general formula "CH3NH3PbX3" (particularly 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 solar cell 10 can be further improved.

[0047] The photoelectric conversion layer is a layer that converts light into electricity. It can include a porous layer and a light-absorbing portion, and refers to a layer located between the first and second conductive layers. The light-absorbing portion is often located between the first and second conductive layers. In such cases, 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 porous, the light-absorbing portion may be present in the area including the first and second conductive layers themselves. In such cases, the first and second conductive layers themselves, where the light-absorbing portion is located, can also be considered as the photoelectric conversion layer. Even in such cases, the photoelectric conversion layer is located at least between the first and second conductive layers. In other words, in any case, a solar cell is provided with a first conductive layer, a photoelectric conversion layer, and a second conductive layer, in that order from the substrate. This does not exclude the first and second conductive layers from being included in the photoelectric conversion layer themselves, nor does it exclude the photoelectric conversion layer being present in areas other than between the first and second conductive layers.

[0048] As described above, the insulating layer 6 is provided for each solar cell 10, and is spaced apart from the insulating layer 6 of an adjacent solar cell 10. Similarly to the insulating layer 6, the second conductive layer 7 is also provided for each solar cell 10, and is spaced apart from the second conductive layer 7 of an adjacent solar cell 10. In this manner, gaps 10a are provided between the solar cells 10 to separate them. In this embodiment, portions of the upper surfaces of the dense electron transport layer 4 and the insulating layer 6 are exposed in the gaps 10a.

[0049] Note that "a gap is provided" or "a gap separating solar cell cells" means that, as shown in FIG. 1, it is sufficient to confirm that a gap exists between the layers to be separated (for example, between the left insulating layer 6 and the right insulating layer 6) in the observation of any cross section of the solar cell; it is not necessary to observe multiple cross sections of the solar cell. Similarly, "any film or layer of a solar cell being separated for each solar cell" means that, as shown in FIG. 1, it is sufficient to confirm that the film or layer is separated in the observation of any cross section of the solar cell; it is not necessary to observe multiple cross sections of the solar cell. Furthermore, "a film or layer of a solar cell being connected to an adjacent solar cell" means that, as shown in FIG. 1, it is sufficient to confirm that the film or layer is connected between adjacent solar cell in the observation of any cross section of the solar cell; it is not necessary to observe multiple cross sections of the solar cell.

[0050] The gap 10a is provided with an intervening portion (referred to as a resistor portion 9 in this embodiment, and hereinafter described as a resistor portion 9) containing a perovskite compound. A plurality of resistor portions 9 are provided in the gap 10a, dispersed in an island shape. The position of the resistor portions 9 in the gap 10a will be described later with reference to FIGS. 3 and 4.

[0051] The term "resistive portion" refers to a portion with low charge mobility or a certain level of electrical resistance. However, this does not exclude portions through which even a small amount of electricity flows. In other words, a resistive portion is sufficient as long as it has a degree of resistance sufficient to provide high separation between adjacent solar cells. For example, the presence of a resistive portion in a gap portion may provide a degree of resistance sufficient to allow a solar cell module to be commercialized. In other words, the degree of resistance of the resistive portion is sufficient as long as a solar cell module having a resistive portion in the gap portion has been commercialized. Since it is extremely difficult to measure the physical properties, such as the resistance value, of the perovskite compound dispersed in the islands formed in the gap portion, it is not necessary to confirm the physical properties, such as the charge mobility or electrical resistance, of the resistive portion; it is sufficient to identify the material.

[0052] Furthermore, since the separation performance of the solar cell module is improved by dispersing multiple perovskite compounds in the gaps in an island-like manner, it is desirable that multiple intervening portions be provided in an island-like manner.

[0053] As described above, the insulating layer 6 protrudes further toward the gap 10a than the second conductive layer 7 in the adjacency direction X. In this way, since the insulating layer 6 protrudes further toward the gap 10a than the second conductive layer 7, there is a margin for error in aligning the second conductive layer 7 with the insulating layer 6, and an unintended structure due to an error in alignment can be avoided.

[0054] In this embodiment, the hole transport layer may be disposed between the perovskite compound, which is the light absorbing section, and the second conductive layer 7. The hole transport layer is a layer that has the function of transporting holes generated in the light absorbing section to the second conductive layer. It is self-evident that, as long as the solar cell has a photoelectric conversion function, the hole transport layer located on the hole transport side (or the positive electrode side, as in the present disclosure) of the light absorbing section or on the hole transport side of the light absorbing section has the function of transporting holes, and confirmation of the hole transport function is not necessary. In other words, as long as the solar cell functions as a solar cell, the layer located on the hole transport side of the light absorbing section or on the hole transport side of the light absorbing section is referred to as the hole transport layer. The hole transport layer may be composed of, for example, a material having a band gap of 2 eV or more and an ionization potential smaller (shallower) than 5.4 eV. The hole transport layer may be composed of an inorganic material. The thickness of the hole transport layer may be, for example, approximately 30 nm or more and 100 nm or less. Specific materials constituting the hole transport layer include oxides and sulfides such as copper oxide (CuO), zinc sulfide (ZnS), and nickel oxide. Fine particles of oxides or sulfides may also be used. Organic materials may also be used. The hole transport layer may be capable of inhibiting electron transport (electron blocking). The hole transport layer may also be accompanied by a separate electron blocking layer. Alternatively, there may be no hole transport layer, and an electron blocking layer may be provided instead.

[0055] Next, a method for manufacturing the solar cell 10 will be described with reference to FIG.

[0056] FIG. 2 is a schematic cross-sectional view showing a step of dropping a perovskite solution in the method for manufacturing a solar cell.

[0057] Fig. 2 shows a schematic cross section of a solar cell 10 (solar cell module 1) in the step of dripping the perovskite solution 8. The first porous layer 51 in Fig. 2 corresponds to the porous electron transport layer 5 before dripping the perovskite solution 8, and the second porous layer 61 in Fig. 2 corresponds to the insulating layer 6 before dripping the perovskite solution 8.

[0058] When fabricating the solar cell 10, a laminated substrate is first fabricated using a typical photolithography process, screen printing process, or the like, in which the portions where each layer of the solar cell 10 will be provided are appropriately set. Specifically, a glass substrate having a fluorine-doped tin oxide film was used for the substrate 2 and the transparent electrode layer 3. A titanium oxide dense layer (dense electron transport layer 4) was then formed on the fluorine-doped tin oxide film using a spray pyrolysis method. Next, a titanium oxide paste was applied to the titanium oxide dense layer and dried to form a titanium oxide porous layer (first porous layer 51). Next, a zirconium dioxide paste was applied to the titanium oxide porous layer and dried to form a zirconium dioxide porous layer (second porous layer 61). Next, a carbon paste was applied to the zirconium dioxide porous layer and dried to form a carbon porous layer (second conductive layer 7). As described above, a photolithography step or a screen printing step may be performed between steps of forming each layer in the laminated substrate, and the portion where each layer is to be provided may be appropriately set or shaped.

[0059] The fabricated laminated substrate has a porous layer, and a perovskite precursor solution (perovskite solution 8) containing a perovskite compound is dripped onto the laminated substrate from above and baked to fabricate a solar cell 10. In this embodiment, the perovskite solution 8 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).

[0060] The perovskite solution 8 dropped onto the laminated substrate permeates the second conductive layer 7, the second porous layer 61, and the first porous layer 51. At this time, the perovskite solution 8 is dropped onto the entire laminated substrate and also into the gaps 10a. The perovskite solution 8 dropped into the gaps 10a does not permeate into the dense electron transport layer 4, but remains on the dense electron transport layer 4.

[0061] Thereafter, baking is performed to evaporate the perovskite solution 8, thereby forming a perovskite compound as a light absorbing portion in the pores of the second conductive layer 7, the second porous layer 61, and the first porous layer 51. The first porous layer 51 functions as an electron transport layer and is therefore referred to as a porous electron transport layer 5, and the second porous layer 61 functions to separate the electron transport layer from the carbon porous layer and is therefore referred to as an insulating layer 6.

[0062] Furthermore, when the remaining perovskite solution 8 is evaporated in the gap portion 10a, a perovskite compound is formed. The formed perovskite compound is partially eliminated by laser irradiation, thereby forming a plurality of dispersed island-like perovskite compounds. This forms the resistor portion 9.

[0063] FIG. 3 shows another embodiment, and is a photograph of the vicinity of the gap taken from above, and FIG. 4 is an enlarged photograph of FIG.

[0064] 3 and 4, the black dots visible at the top correspond to the resistor portions 9, and multiple resistor portions 9 are provided in the gaps 10a, dispersed in an island pattern. The resistor portions 9 provided in the gaps 10a act as insulators between the solar cells 10, inhibiting current leakage and improving the efficiency of the solar cells 10. Furthermore, because multiple resistor portions 9 are provided at separate intervals, current leakage in the gaps 10a can be more effectively inhibited.

[0065] It should be noted that the embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present disclosure should not be interpreted solely by the above-described embodiments, but should be defined based on the claims. Furthermore, all modifications within the scope and meaning equivalent to the claims are included. [Explanation of symbols]

[0066] 1. Solar cell module 2 Base 3 Transparent electrode layer 4 Dense electron transport layer 5 Porous electron transport layer 6 insulating layer 6a Top surface of insulating layer 7 Second conductive layer 8 Perovskite solution 9 Resistance part 10 solar cells 10a Gap X adjacent direction

Claims

1. A solar cell module having a plurality of solar cells, The solar cell includes a base body, a first conductive layer, a photoelectric conversion layer, and a second conductive layer in this order, the photoelectric conversion layer has a light absorbing portion and a porous layer, a gap is provided between the porous layer of any one of the solar cells and the porous layer of an adjacent solar cell; The gap portion is provided with an intervening portion including a light absorbing portion. A solar cell module characterized by:

2. The solar cell module according to claim 1, The light absorbing portion contains a perovskite compound. A solar cell module characterized by:

3. The solar cell module according to claim 1, The intervening portion is provided in a plurality of islands in the gap. A solar cell module characterized by:

4. The solar cell module according to claim 1, the porous layer protrudes further toward the gap than the second conductive layer in the direction in which the adjacent solar cells are arranged. A solar cell module characterized by:

5. The solar cell module according to claim 1, the porous layer includes an insulating layer; The insulating layer comprises zirconium oxide. A solar cell module characterized by:

6. A method for manufacturing a solar cell module having a plurality of solar cells, comprising: providing a first conductive layer, a photoelectric conversion layer, and a second conductive layer in this order from a substrate in the solar cell; the photoelectric conversion layer has a light absorbing portion and a porous layer, a gap is provided between the porous layer of any one of the solar cells and the porous layer of an adjacent solar cell; The gap portion is provided with an intervening portion including a light absorbing portion. A method for manufacturing a solar cell module, comprising:

7. The method for manufacturing a solar cell module according to claim 6, The method includes a step of impregnating the pores of the porous layer with a perovskite compound and forming the intermediate portion. A method for manufacturing a solar cell module, comprising:

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