Solar cell and method for manufacturing solar cell

Abstract

A solar cell 100 in which one or more photoelectric conversion elements 10(1) to 10(n) are formed on a substrate 1 in which a first conductive film 2 and a first charge transport layer 3 are arranged in the stated order on the surface on one side of a substrate 1 comprises wiring regions βA, βB connecting wiring materials (6, 7) to the first conductive film 2, one or more holes 8A, 8B are formed in the first charge transport layer 3 in the wiring regions βA, βB, and the one or more holes 8A, 8B include holes having a depth reaching at least the first conductive film 2. The method for manufacturing the solar cell 100 includes a first step for forming a first charge transport layer 3 on a first conductive film 2 formed on the surface on one side of a substrate 1, and a second step for forming one or more holes 8A, 8B in the first charge transport layer 3 in the wiring regions βA, βB.

Description

Solar cell and method for manufacturing solar cell

[0001] The present disclosure relates to a solar cell in which one or more photoelectric conversion elements are formed on a substrate having a first conductive film and a first charge transport layer disposed in this order on one surface of the substrate, and a method for manufacturing the solar cell.

[0002] Fig. 16 is a cross-sectional view schematically showing a solar cell 1X described in Patent Document 1. Fig. 17 is a cross-sectional view schematically showing a conventional solar cell 100Y including one or more example photoelectric conversion elements 10Y(1) to 10Y(m) (m is an integer of 1 or more). In Fig. 17, reference symbols 4Y and 5Y respectively represent a photoelectric conversion layer and a second conductive film (a second electrode, for example, a back electrode).

[0003] As shown in FIG. 16 , the solar cell 1X described in Patent Document 1 includes a substrate 3X, multiple solar cell elements 2X, a connection portion 4X, and a transparent portion 5X. Each solar cell element 2X includes a first electrode layer 2aX, a semiconductor layer 2bX, and a second electrode layer 2cX. The first electrode layer 2aX is located on the substrate 3X. The semiconductor layer 2bX is located between the first electrode layer 2aX and the second electrode layer 2cX. The semiconductor layer 2bX has a structure in which, for example, a semiconductor layer having a perovskite structure and a hole transport layer are stacked. The first electrode layer 2aX located on the edge side has a first protrusion 2aeX that protrudes beyond the semiconductor layer 2bX and the second electrode layer 2cX to reach the edge. A first conductor W1X for outputting a first polarity is connected to the first protrusion 2aeX (see paragraphs

[0012] ,

[0015] ,

[0016] ,

[0019] ,

[0020] , and

[0031] ).

[0004] Re-table 2018 / 043644 publication

[0005] However, as shown in Figure 17, a solar cell 100Y in which one or more photoelectric conversion elements 10Y(1) to 10Y(m) are formed on a base 1Y having a first conductive film 2Y and a first charge transport layer 3Y (electron transport layer or hole transport layer) arranged in this order on one surface of the base 1Y has the following disadvantages.

[0006] That is, in the solar cell 100Y, due to the manufacturing process of the solar cell 100Y, a first charge transport layer 3Y may be formed over the entire surface of the first conductive film 2Y opposite the base 1Y. In this case, the first wiring member 6Y and the first conductive film 2Y come into contact with each other through the first charge transport layer 3Y. This reduces the power that can be extracted from the solar cell 100Y due to the electrical resistance of the first charge transport layer 3Y. Furthermore, in a configuration in which the second wiring member 7Y can be connected to the second conductive film 5Y, if the second wiring member 7Y is directly connected to the second conductive film 5Y, power can be extracted directly from the second conductive film 5Y. However, as in the illustrated example, the second wiring member 7Y may come into contact with the first conductive film 2Y through the first charge transport layer 3Y. In this case, as with the first wiring member 6Y, the electrical resistance of the first charge transport layer 3Y reduces the power that can be extracted from the solar cell 100Y.

[0007] Therefore, an object of the present disclosure is to provide a solar cell that can effectively prevent a decrease in the power that can be extracted from the solar cell, and a method for manufacturing the solar cell.

[0008] In order to solve the above problems, the following solar cell and method for manufacturing the solar cell are provided.

[0009] (1) Solar Cell The solar cell according to the present disclosure is a solar cell in which one or more photoelectric conversion elements are formed on a substrate having a first conductive film and a first charge transport layer arranged in this order on one side of the substrate, and the solar cell has a wiring region for connecting wiring material to the first conductive film, and in the wiring region, one or more holes are formed in the first charge transport layer, and the one or more holes include holes that are at least deep enough to reach the first conductive film.

[0010] (2) Method for manufacturing a solar cell The method for manufacturing a solar cell according to the present disclosure is a method for manufacturing a solar cell according to the present disclosure, comprising a first step of forming the first charge transport layer on the first conductive film formed on one side of the base, and a second step of forming the one or more holes in the first charge transport layer in the wiring region.

[0011] According to the present disclosure, it is possible to effectively prevent a decrease in the power that can be extracted from a solar cell.

[0012] FIG. 1A is a plan view schematically showing a solar cell according to the present embodiment. FIG. 1B is a cross-sectional view of the solar cell according to the present embodiment taken along line B-B shown in FIG. 1A. FIG. 1C is a cross-sectional view schematically showing a hole portion in the solar cell according to the present embodiment. FIG. 2A is a cross-sectional view for explaining an example of a wiring region. FIG. 2B is a cross-sectional view for explaining another example of a wiring region. FIG. 3 is a process diagram of an example of a method for manufacturing a solar cell. FIG. 4A is a cross-sectional view schematically showing a second step in the method for manufacturing a solar cell. FIG. 4B is a cross-sectional view schematically showing a third step in the method for manufacturing a solar cell. FIG. 4C is a cross-sectional view schematically showing a fourth step in the method for manufacturing a solar cell. FIG. 5 is a plan view schematically showing an example of a solar cell according to the first embodiment. FIG. 6 is a plan view schematically showing an example of a solar cell according to the second embodiment. FIG. 7 is a plan view schematically showing an example of a solar cell according to the third embodiment. FIG. 8 is a plan view schematically showing an example of a solar cell according to the fourth embodiment. FIG. 9 is a plan view schematically showing an example of a solar cell according to the fifth embodiment. FIG. 10A is a plan view schematically showing another example of a solar cell according to the sixth embodiment. FIG. 10B is a cross-sectional view of the solar cell according to the sixth embodiment taken along line B-B shown in FIG. 10A. FIG. 11 is a cross-sectional view schematically showing an example of a solar cell according to the seventh embodiment. FIG. 12 is a cross-sectional view schematically showing an example of a solar cell according to the eighth embodiment. FIG. 13 is a cross-sectional view schematically showing an example of a solar cell according to the ninth embodiment. FIG. 14 is a cross-sectional view schematically showing an example of a solar cell according to the tenth embodiment. FIG. 15A is a cross-sectional view schematically showing an example of a solar cell according to the eleventh embodiment. FIG. 15B is a cross-sectional view schematically showing another example of a solar cell according to the eleventh embodiment. FIG. 15C is a cross-sectional view schematically showing yet another example of a solar cell according to the eleventh embodiment. FIG. 16 is a cross-sectional view schematically showing a solar cell described in Patent Document 1. FIG. 17 is a cross-sectional view schematically showing a conventional solar cell including one or more example of photoelectric conversion elements.

[0013] Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings. In the following description, identical components are assigned the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated. As an example, the base side is expressed as the lower side and the opposite side as the upper side, but this is for convenience and does not relate to the installation direction or the recommended installation direction. As long as there is no contradiction, it is applicable even if the top and bottom are reversed or the left and right are rephrased.

[0014] FIG. 1A is a plan view schematically illustrating a solar cell 100 according to the present embodiment. FIG. 1B is a cross-sectional view of the solar cell 100 according to the present embodiment taken along line B-B shown in FIG. 1A. FIG. 1C is a cross-sectional view schematically illustrating the hole (first hole 8A and second hole 8B) portion of the solar cell 100 according to the present embodiment. FIGS. 2A and 2B are cross-sectional views for explaining an example and another example of wiring regions βA and βB, respectively. Note that the first hole 8A and the second hole 8B have the same configuration, and therefore are shown in a single view in FIGS. 1C, 2A, and 2B.

[0015] In the solar cell 100 according to the present embodiment, a first conductive film 2 (first electrode, in this example, a transparent conductive film (transparent conductive layer)) and a first charge transport layer 3 (in this example, an electron transport layer) are disposed in this order on one surface of a base 1 (the same as or including a base material or substrate; the same applies in the present disclosure). In this example, a photoelectric conversion layer 4 and a second conductive film 5 are further formed in this order on the surface of the first charge transport layer 3 opposite the first conductive film 2. Note that, from the viewpoint of improving the power generation efficiency of the solar cell 100, a second charge transport layer (e.g., a hole transport layer) may be formed between the photoelectric conversion layer 4 and the second conductive film 5. Unless otherwise specified, the term "film" does not specify the thickness or width, and includes patterned or island-shaped structures and structures having portions of different thicknesses. A film preferably has a substantially uniform thickness. Unless otherwise specified, the term "layer" does not specify the thickness or width, and includes patterned or island-shaped structures and structures having portions of different thicknesses. A layer preferably has a substantially uniform thickness. Unless otherwise specified, the terms "approximately" and "approximately" refer to the margin of manufacturing error, and preferentially indicate that a variation of plus or minus 15% of the numerical value is permitted.

[0016] In this example, the solar cell 100 has a structure in which an electron transport layer is formed (deposited) on the first conductive film 2 as the first charge transport layer 3, but a structure in which a hole transport layer is formed instead of the electron transport layer may also be used. That is, the first charge transport layer 3 may be an electron transport layer or a hole transport layer. In the case where a second charge transport layer is formed between the photoelectric conversion layer 4 and the second conductive film 5, if the first charge transport layer 3 is an electron transport layer, the second charge transport layer is a hole transport layer, and if the first charge transport layer 3 is a hole transport layer (the reverse structure), the second charge transport layer is an electron transport layer.

[0017] The substrate 1 has one or more photoelectric conversion elements 10(1) to 10(m) (where m is an integer greater than or equal to 1) (also referred to as solar cell cells). The substrate 1 has wiring regions βA, βB (busbar regions) (see FIGS. 2A and 2B ) that connect wiring members (in this example, first wiring member 6 and second wiring member 7) (busbars) to the first conductive films 2, 2 located at the end portions. In the wiring regions βA, βB, one or more (in this example, one) holes 8A, 8B (recesses) are formed in the first charge transport layers 3, 3 located at the end portions. The one or more holes 8A, 8B include holes deep enough to reach at least the first conductive films 2, 2. In this example, the holes 8A, 8B are formed in at least a portion of the wiring regions βA, βB (in this example, a portion, specifically, a central portion in the width direction H perpendicular to the longitudinal direction L of the wiring regions βA, βB).

[0018] Solar cell 100 according to this embodiment has a structure of wiring regions βA and βB. In solar cell 100, wiring regions βA and βB are provided at at least one end (both ends in this example) in the width direction H. Specifically, in the width direction H, the end on one side H1 (the left side in the illustrated example) has a structure of wiring region βA that connects first wiring member 6 to first conductive film 2, and the end on the other side H2 (the right side in the illustrated example) has a structure of wiring region βB that connects second wiring member 7 to second conductive film 5 (second electrode, back electrode in this example) via first conductive film 2. Note that with regard to the end on the other side H2 (the right side), if the second wiring member 7 can be connected to second conductive film 5, the second wiring member 7 may be directly connected to second conductive film 5.

[0019] <"Hole"> In the present disclosure, the term "hole (8A, 8B)" encompasses a concept that includes a groove. The hole can be filled with a conductive material (F) (in this example, a conductive adhesive), and the hole can be filled with the conductive material. Therefore, the term "hole" also encompasses a concept that includes a hole filled with a conductive material. On the other hand, the term "hole" does not include a case where the first charge transport layer (3) is absent on either side (H1 or H2) of the wiring region (βA, βB) in the width direction (H) and reaches the end of the first conductive film (2). In other words, a "hole" refers to a portion displaced toward the substrate (1) from the surface of the first charge transport layer, where the first charge transport layer is absent at the bottom in the depth direction (D), and where the first charge transport layer is present on both sides in the width direction. Here, the width [W (see Figures 2A and 2B)] (size in the width direction) of the hole can be, for example, approximately 100 μm to 1 mm. It should be noted that a "hole" does not necessarily have to be completely free of the first charge transport layer at its bottom. That is, it is sufficient that there is a region at the bottom of the "hole" where the first charge transport layer is not present, and there may also be a region where the first charge transport layer is present.

[0020] More specifically, of the first wiring member 6 and the second wiring member 7, at least the first wiring member 6 is connected to the first conductive film 2 via a conductive material F (in this example, a conductive adhesive). In this example, not only is the first wiring member 6 connected to the first conductive film 2 via the conductive material F, but because it is difficult to connect the second wiring member 7 to the second conductive film 5, the second wiring member 7 is also connected to the first conductive film 2 via the conductive material F. This improves the efficiency of current extraction from the first conductive film (2).

[0021] <"Wiring Region"> In the present disclosure, the "wiring region (βA, βB)" refers to a region corresponding to the conductive material (F) that connects the wiring members (6, 7) to the solar cell (100) in a plan view, because current flows where the conductive material is present.

[0022] In the example shown in Figure 2A, the conductive material F does not protrude from the wiring members (6, 7), and the width d1 of the wiring regions βA and βB is smaller than the width d2 of the first wiring member 6 and the second wiring member 7. In the example shown in Figure 2B, the conductive material F protrudes from the wiring members (6, 7), and the width d1 of the wiring regions βA and βB is larger than the width d2 of the first wiring member 6 and the second wiring member 7. The width d1 of the wiring regions βA and βB (size in the width direction H) can be, for example, about 2 mm to 3 mm.

[0023] 1A and 1B, in a solar cell 100, photoelectric conversion elements 10(1) to 10(m) are configured with a first conductive film 2, a first charge transport layer 3 (an electron transport layer in this example), a photoelectric conversion layer 4, and a second conductive film 5. When a second charge transport layer (e.g., a hole transport layer) is formed between the photoelectric conversion layer 4 and the second conductive film 5, the first conductive film 2, the first charge transport layer 3, the photoelectric conversion layer 4, the second charge transport layer, and the second conductive film 5 configure the photoelectric conversion elements 10(1) to 10(m).

[0024] In the solar cell 100, the first conductive film 2, the first charge transport layer 3, the photoelectric conversion layer 4, and the second conductive film 5 are connected in series between the first wiring member 6 and the second wiring member 7 in the photoelectric conversion elements 10(1) to 10(m). In this example, the first wiring member 6 is the negative electrode, and the second wiring member 7 is the positive electrode. When a second charge transport layer is formed between the photoelectric conversion layer 4 and the second conductive film 5, the first conductive film 2, the first charge transport layer 3, the photoelectric conversion layer 4, the second charge transport layer, and the second conductive film 5 are connected in series between the first wiring member 6 and the second wiring member 7. Note that when m is 2 or more, the individual photoelectric conversion elements 10(1) to 10(m) are connected in series. In this case, the solar cell 100 is a series-connected solar cell.

[0025] The solar cell 100 according to this embodiment has a perovskite layer with an MPLE (Multiporous-Layered-Electrodes) structure.

[0026] Here, the MPLE structure is a structure in which a perovskite layer is formed in which a perovskite material is provided in the voids in a spacer layer that is a porous layer having multiple voids, as the photoelectric conversion layer 4. However, the photoelectric conversion layer 4 in the solar cell 100 according to the present embodiment is not limited to a perovskite layer with an MPLE structure, and may be, for example, a planar solar cell with a flat multilayer structure.

[0027] The solar cell 100 according to the present embodiment is not limited to solar cells using a perovskite material, and can be suitably used in any solar cell in which a first charge transport layer is formed on a first conductive film. For example, a dye-sensitized solar cell can be given as an example of a solar cell in which a first charge transport layer is formed on a first conductive film.

[0028] <Base> Examples of materials that can be used as the base 1 include a glass substrate and an organic film. Specific 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 will become the base 1 is preferably approximately 50 μm to 100 μm.

[0029] <First Conductive Film> The first conductive film 2 is provided on the substrate 1 and serves as an electrode for extracting current generated by photovoltaic power in the photoelectric conversion layer 4 of each of the photoelectric conversion elements 10(1) to 10(m). When the substrate 1 is on the light incident side, the first conductive film 2 can be a transparent conductive film. Examples of transparent conductive films include those containing transparent conductive oxides (TCOs). Transparent conductive films can be made of conductive transparent materials such as aluminum-doped zinc oxide (AZO), indium zinc oxide (IZO), gallium-doped zinc oxide (GZO), fluorine-doped tin oxide (FTO), and indium tin oxide (ITO). The first conductive film 2 may also be made of an oxide of a conductive transparent material, on which thin lines of a conductive metal such as silver are patterned. The term "transparent" means that the film transmits light, but does not exclude films that reflect or absorb light even slightly, and means that the film is provided on the light-receiving surface side of the photoelectric conversion element (including the portion where light is incident, the same applies in the present disclosure). Therefore, the film can be considered transparent if it is provided at least on the light-receiving surface side. In other words, the transparent conductive film means a conductive film provided on the light-receiving surface side of the photoelectric conversion element.

[0030] <First Charge Transport Layer> The first charge transport layer 3 is a charge transport layer that transports electrons generated in the photoelectric conversion layer 4 to the first conductive film 2. It is self-evident that the electron transport layer located on the electron transport side of the photoelectric conversion layer 4 has the function of transporting electrons as long as the solar cell functions as a solar cell, and no further confirmation is required. In other words, as long as the solar cell functions as a solar cell, the layer located on the electron transport side of the photoelectric conversion layer 4 is referred to as the electron transport layer. The electron transport layer is made of a material that allows electrons generated in the photoelectric conversion layer 4 to easily move to the electron transport layer and that allows electrons from the electron transport layer to easily move to the first conductive film 2. The electron transport layer may also be a seed layer for oriented growth of the photoelectric conversion layer 4. This can improve the crystalline quality of the perovskite compound that constitutes the photoelectric conversion layer 4. The electron transport layer may be, for example, a titanium dioxide (TiO2) layer. Furthermore, a TiN layer or a TiO2-xNx layer may be formed on the surface of the titanium dioxide contained in this titanium dioxide layer. The electron transport layer may be made of stannic oxide (SnO2). The thickness of the electron transport layer is, for example, about 100 nm to 250 nm.

[0031] The holes 8A and 8B can be formed in the first charge transport layer 3 by, for example, cutting (scribing) such as mechanical processing or laser processing, which will be described in detail later.

[0032] <Photoelectric Conversion Layer> The photoelectric conversion layer 4 is a layer capable of absorbing light. It is a layer capable of absorbing light incident on the photoelectric conversion elements 10(1) to 10(m) and generating electrons and holes. These electrons move to the electron transport layer, and when a second charge transport layer is formed, the holes move to the hole transport layer. The fact that the photoelectric conversion layer 4 absorbs light and generates electrons and holes is self-evident as long as the solar cell 100 functions as a solar cell, and does not require confirmation. As long as a material with light absorption function is included, it can be considered that the photoelectric conversion layer 4 absorbs light and generates electrons and holes.

[0033] When the solar cell 100 has a perovskite layer with an MPLE structure, the photoelectric conversion elements (1) to 10(m) may have a photoelectric conversion layer 4 in the pores of the porous insulating layer. Specifically, the photoelectric conversion elements (1) to 10(m) may have a light-absorbing portion made of the material used in the photoelectric conversion layer 4 in the pores of the porous insulating layer. In this embodiment, the light-absorbing portion refers to a portion made of the light-absorbing material used in the photoelectric conversion layer 4. One or more light-absorbing portions can be described as a photoelectric conversion layer. In other words, the light-absorbing portion can refer to a portion that is an arbitrary region in the photoelectric conversion layer. Furthermore, the photoelectric conversion layer can refer to a collection of light-absorbing portions that exist discretely or continuously in a region having a thickness, primarily in a certain direction. When the second conductive film 5 is porous, the light-absorbing portion may also be provided in at least some of the pores of the second conductive film 5.

[0034] The photoelectric conversion layer 4 preferably contains a perovskite compound or an organic-inorganic hybrid compound. This compound can generate electrons and holes in the photoelectric conversion layer 4. The film thickness of the photoelectric conversion layer 4 is preferably within a range of approximately 500 nm to 1000 nm.

[0035] The perovskite compound contained in the light-absorbing portion is composed of a compound represented by the general formula: ABX (1). However, while the composition ratio of each element is preferably 1:1:3, it does not necessarily have to be 1:1:3. The content of each element may vary as appropriate, and each constituent element does not necessarily have to be a single type. As long as the 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 configuration as described in 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, the same applies in the present disclosure) or an inorganic atom or molecule (including an inorganic group or an inorganic cation, the same applies in the present disclosure) or a combination thereof; B is a metal atom or molecule (including a metal cation, the same applies in the present disclosure); and X is a halogen atom or molecule or a chalcogen atom or molecule (including a halogen anion or a chalcogen anion, the same applies in the present disclosure). In general formula (1), the three Xs may be the same or different. As long as the 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 the solar cell has a photoelectric conversion function, it can be confirmed that the compound 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 know that a compound is a perovskite compound if it contains A, B, and X. For example, it is sufficient to know 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.

[0036] 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.

[0037] In general formula (1), examples of the organic molecule represented by A include alkylamine, alkylammonium, and nitrogen-containing heterocyclic compounds. In the perovskite compound (1), the organic molecule represented by A may be only one type of organic molecule, or may be two or more types of organic molecules.

[0038] 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.

[0039] 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.

[0040] 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. Phenethylammonium is preferred as the ionized nitrogen-containing heterocyclic compound.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] As the perovskite compound, a compound represented by the general formula "CH3NH3PbX3 (wherein X represents a halogen atom)" is preferred, with CH3NH3PbI3 being more preferred. 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 photoelectric conversion elements 10(1) to 10(m) can be further improved.

[0045] <Second Conductive Film> The second conductive film 5 is provided on the photoelectric conversion layer 4 and is an electrode for extracting current generated by the photovoltaic power of the photoelectric conversion elements 10(1) to 10(m). Examples of materials for the second conductive film 5 include metals such as Ni, Pt, and Pd. The film thickness of the second conductive film 5 is preferably approximately 50 nm to 150 nm. The second conductive film 5 can be formed by, for example, a sputtering method or a vacuum deposition method. Specific examples of materials constituting the second conductive film 5 include conductive materials such as graphite, graphene, carbon nanowires, carbon nanofibers, carbon nanotubes, and carbon black. In the case of such materials, the second conductive film 5 can be porous. Basically, any conductive material is acceptable.

[0046] <Second Charge Transport Layer> When a second charge transport layer is provided between the photoelectric conversion layer 4 and the second conductive film 5, the second charge transport layer is a hole transport layer that has the function of transporting holes generated in the photoelectric conversion layer 4 to the second conductive film 5. It is self-evident that the hole transport layer located on the hole transport side of the photoelectric conversion layer 4 or on the hole transport side of the photoelectric conversion layer 4 has the function of transporting holes, so confirmation is not required, as long as the solar cell 100 functions as a solar cell. In other words, as long as the solar cell 100 functions as a solar cell, the layer located on the hole transport side of the photoelectric conversion layer 4 or on the hole transport side of the photoelectric conversion layer 4 is referred to as the hole transport layer. The thickness of the hole transport layer can be, for example, approximately 30 nm to 100 nm. Specific materials constituting the hole transport layer include oxides and sulfides such as copper oxide (CuO) and zinc sulfide (ZnS). The hole transport layer can be formed, for example, by a sputtering method or a vacuum deposition method.

[0047] (Method of manufacturing solar cell) Figure 3 is a process diagram of an example of a method of manufacturing solar cell 100. Figures 4A to 4C are cross-sectional views that schematically show the second step S2 to the fourth step S4, respectively, in the method of manufacturing solar cell 100. In Figure 4A, γ1 is an element formation region (cell formation region) where photoelectric conversion elements 10(1) to 10(m) (solar cell) are formed, and γ2 is a bus bar attachment region where the first bus bar (6) and the second bus bar (7) are attached.

[0048] The manufacturing method of the solar cell 100 according to this embodiment includes a first step S1 of forming a first charge transport layer 3 (an electron transport layer in this example) on a first conductive film 2 (a transparent conductive film in this example) formed on one surface of a substrate 1, and a second step S2 of forming one or more holes 8A, 8B in the first charge transport layer 3 in wiring regions βA, βB by cutting processing such as mechanical processing and laser processing.

[0049] Here, the mechanical processing and the laser processing are conventionally known processing methods, and are processing using a cutting blade and a cutting laser beam, respectively. These cutting processes also apply to the cutting process for forming separation grooves for dividing cells, which will be described later.

[0050] The method for manufacturing the solar cell 100 according to this embodiment will be described by taking as an example a solar cell 100 having a perovskite layer with an MPLE structure.

[0051] [First Step] <Formation of Transparent Conductive Film> First, in the first step S1, a transparent conductive film (an example of the first conductive film 2) is formed on one surface of a glass substrate (an example of the base 1) (see S1-1 in FIG. 3 and FIG. 4A). Materials used for the transparent conductive film (2) include indium tin oxide (ITO) and tin oxide (FTO). The transparent conductive film (2) is formed by a known method such as a sputtering method or a CVD method.

[0052] <Formation of Electron Transport Layer> Next, an electron transport layer (an example of the first charge transport layer 3) is formed on the transparent conductive film (2) (see S1-2 in FIG. 3 and FIG. 4A). Materials used for the electron transport layer (3) include titanium dioxide (TiO2) and stannic oxide (SnO2). The electron transport layer (3) is formed by a known method such as sputtering or spin coating.

[0053] [Second Step] <Formation of Holes and Separation Grooves> Next, in the second step S2, the electron transport layer (3) is cut (in this example, laser processing (laser scribing)) to form first holes 8A and second holes 8B that reach at least the transparent conductive film (2), and further to form separation grooves 9 for separating cells (see S2-1 in FIG. 3 and FIG. 4A). The first holes 8A and second holes 8B are holes for attaching a first bus bar (an example of the first wiring member 6) and a second bus bar (an example of the second wiring member 7). Here, the laser light used in the laser processing is a beam of fundamental wave (1064 nm) of a YAG laser.

[0054] [Third Step] <Formation of Porous Insulating Layer> Next, in the third step S3, a porous insulating layer 40 is formed in the separation groove 9 (see S3-1 in FIG. 3 and FIG. 4B). The material used for the porous insulating layer 40 is porous zirconium dioxide (porous ZrO2). The porous insulating layer 40 is formed by a known method such as screen printing.

[0055] <Formation of Porous Rear Electrode> Next, a porous rear electrode (electrode layer) (an example of the second conductive film 5) is formed on the porous insulating layer 40 and the separation groove 9 (see S3-2 in FIG. 3 and FIG. 4B). Materials used for the porous rear electrode (5) include carbon nanofibers, carbon nanotubes, and carbon black. The porous rear electrode (5) is formed by a known method such as screen printing.

[0056] <Dropping of Perovskite Material Liquid> Next, in the element formation region γ1, the perovskite material liquid Q is dropped from the porous back electrode (5) (see S3-3 in FIG. 3 and FIG. 4B). The perovskite material liquid Q permeates the porous back electrode (5) and the porous insulating layer 40, and the porous insulating layer 40 permeated with the perovskite material liquid Q dries to become the photoelectric conversion layer 4.

[0057] [Fourth Step] <Application of Conductive Adhesive to Busbar Mounting Region> Next, in the fourth step S4, the conductive adhesive (F, F) is applied to the first holes 8A and the second holes 8B in the busbar mounting regions γ2, γ2 (see S4-1 in FIG. 3 and FIG. 4C ). At this time, the conductive adhesive (F, F) filled in the first holes 8A and the second holes 8B is allowed to slightly protrude from the first holes 8A and the second holes 8B. A general thermosetting conductive adhesive is used as the conductive adhesive (F, F). The conductive adhesive (F, F) is applied using a known method such as a dispenser. It is desirable that the conductive adhesive (F, F) be one that hardens at as low a temperature as possible (for example, 100°C or less) so as not to cause deterioration of the photoelectric conversion layer 4.

[0058] <Attaching the bus bars> The first bus bar (6) and the second bus bar (7) are placed in the holes 8A and 8B to which the conductive adhesive (F, F) has been applied (see S4-2 in FIG. 3 and FIG. 4C), and the conductive adhesive (F, F) is heated and hardened, thereby attaching the first bus bar (6) and the second bus bar (7) to the conductive adhesive (F, F).

[0059] As described above, in the method for manufacturing the solar cell 100 according to the present embodiment, holes 8A and 8B are formed by laser scribing in the transparent conductive film (2) covered with the electron transport layer (3), reaching at least the transparent conductive film (2), and conductive adhesives (F, F) are brought into contact with the holes 8A and 8B, and the bus bars (6, 7) are attached to the electron transport layer (3) by the conductive adhesives (F, F). In this way, even if the transparent conductive film (2) is covered with the electron transport layer (3), power supplied from the transparent conductive film (2) can be extracted from the bus bars (6, 7) via the conductive adhesives (F, F) provided in the holes 8A and 8B.

[0060] According to the present embodiment, even if the first charge transport layer 3 (in this example, an electron transport layer) is formed over the entire surface of the first conductive film 2 opposite the substrate 1 due to reasons such as the process for manufacturing the solar cell 100, the wiring material, specifically the first wiring material 6, can be reliably connected to the first conductive film 2 through one or more holes 8A that are deep enough to reach at least the first conductive film 2. Furthermore, in this example, since it is difficult to connect the second wiring material 7 to the second conductive film 5, the second wiring material 7 can be reliably connected to the first conductive film 2 through one or more holes 8B that are deep enough to reach at least the first conductive film 2. This prevents a decrease in the power that can be extracted from the solar cell 100, regardless of the electrical resistance of the first charge transport layer 3.

[0061] First Embodiment Fig. 5 is a plan view schematically illustrating an example of a solar cell 100 according to a first embodiment. Note that the first wiring member 6, the second wiring member 7, and the conductive materials F, F are omitted from Fig. 5. This also applies to Figs. 6 to 15C, which will be described later.

[0062] In solar cell 100 according to the present embodiment, holes 8A and 8B are linear holes (grooves). In the method for manufacturing solar cell 100 according to the present embodiment, linear (groove-shaped) holes 8A and 8B are formed in second step S2.

[0063] In this embodiment, the shape of the scribe regions δA and δB, which are regions where at least the first charge transport layer 3 has been removed by cutting, when viewed in a plane is a continuous region in the longitudinal direction L, as shown in Figure 5.

[0064] In this embodiment, an example of a hole (8A in this example) provided at the end on at least one side (one side H1 in this example) in the width direction H is formed to reach the end faces (both end faces in this example) on at least one side (L1 and / or L2) of both end faces in the longitudinal direction L. Another example of a hole (8B in this example) provided at the end on at least one side (the other side H2 in this example) in the width direction H is formed to reach partway through both end faces in the longitudinal direction L, but not to reach both end faces.

[0065] In the scribe regions δA and δB shown in FIG. 5 , the hole 8A formed in the scribe region δA at the end of one side H1 in the width direction H is an example of a groove (long, thin, linear hole) extending in the longitudinal direction L by cutting to the end face (upper end face in the figure) of one side L1 and the end face (lower end face in the figure) of the other side L2 in the longitudinal direction L of the substrate 1. The hole 8B formed in the scribe region δB at the end of the other side H2 in the width direction H is a groove extending in the longitudinal direction L, similar to the scribe region δA, but is an example of a groove (long, thin, linear hole) that does not reach the end face (upper end face in the figure) of one side L1 and the end face (lower end face in the figure) of the other side L2 in the longitudinal direction L of the substrate 1 by cutting, leaving the first charge transport layer 3 at both ends. Such a groove is also included in the "hole" of the present disclosure.

[0066] In this way, the holes 8A and 8B are linear holes, and by forming the linear holes 8A and 8B, cutting can be performed relatively easily.

[0067] In the solar cell 100 according to the present embodiment, the photoelectric conversion elements 10(1) to 10(m) have a photoelectric conversion layer 4 and a second conductive film 5 formed in this order on a first charge transport layer 3. In the manufacturing method for the solar cell 100 according to the present embodiment, in the third step S3, the photoelectric conversion layer 4 and the second conductive film 5 are formed in this order on the first charge transport layer 3. The photoelectric conversion layer 4 has a light absorption layer containing perovskite. This makes it possible to suitably use the structure of the holes 8A and 8B according to the present embodiment for the solar cell 100 containing perovskite.

[0068] In the solar cell 100 and the method for manufacturing the solar cell 100 according to the present embodiment, a plurality of photoelectric conversion elements 10(1) to 10(m) are formed on the base 1. In this way, the structure of the holes 8A, 8B according to the present embodiment can be suitably used for the solar cell 100 in which the plurality of photoelectric conversion elements 10(1) to 10(m) are formed.

[0069] Second Embodiment In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. This also applies to the third to eleventh embodiments described later.

[0070] FIG. 6 is a plan view schematically illustrating an example of a solar cell 100 according to the second embodiment.

[0071] In solar cell 100 according to the present embodiment, holes 8A and 8B are island-shaped holes. In the method for manufacturing solar cell 100 according to the present embodiment, island-shaped holes 8A and 8B are formed in second step S2.

[0072] In this embodiment, the holes 8A, 8B formed in the scribe regions δA, δB are in the form of multiple islands (e.g., dotted lines, broken lines). The multiple island-shaped holes (8A-8A), (8B-8B) are arranged side by side at predetermined intervals in the longitudinal direction L. Therefore, the scribe regions δA, δB are island-shaped regions including multiple island-shaped holes. Although the scribe regions δA, δB are composed of a single island-shaped region, they may also be composed of multiple island-shaped regions formed at intervals in the longitudinal direction L.

[0073] 6, the shape of each of the holes 8A-8A and 8B-8B in the island-shaped scribe regions δA and δB is square. However, this is not limiting, and the shape of the holes 8A and 8B may be rectangular, circular, elliptical, square with rounded corners (arcuate), or any other shape.

[0074] In this way, the holes 8A, 8B are island-shaped holes, and by forming the island-shaped holes 8A, 8B, the contact surfaces 2a (see FIG. 1C) (hereinafter sometimes simply referred to as "contact surfaces") of the first conductive film 2 with the conductive adhesive (F) can be the bottom and / or side surfaces of the individual holes 8A-8A and 8B-8B in the island-shaped regions of the first conductive film 2. As a result, for example, compared to the linear holes 8A, 8B of the first embodiment, the contact surfaces 2a (see FIG. 1C) in the longitudinal direction L in plan view are reduced, but the area of ​​the contact surfaces 2a in the width direction H can be increased, thereby reducing the electrical resistance between the first conductive film 2 and the conductive adhesive (F). The contact surfaces 2a will be described in detail in the seventh to eleventh embodiments described below.

[0075] Third Embodiment FIG. 7 is a plan view schematically illustrating an example of a solar cell 100 according to a third embodiment.

[0076] In solar cell 100 according to the present embodiment, holes 8A, 8B form hole rows (8A1, 8A2), (8B1, 8B2) consisting of multiple rows of island-shaped holes. In the method for manufacturing solar cell 100 according to the present embodiment, in second step S2, holes 8A, 8B that form hole rows (8A1, 8A2), (8B1, 8B2) consisting of multiple rows of island-shaped holes are formed.

[0077] In this way, the holes 8A and 8B form hole rows (8A1, 8A2) and (8B1, 8B2), and by forming the holes 8A and 8B that form the hole rows (8A1, 8A2) and (8B1, 8B2), it is possible to increase the contact surface 2a, thereby improving the conductivity between the first conductive films 2 and the wiring materials (first wiring material 6 and second wiring material 7). For example, compared with the scribe regions δA and δB in the second embodiment, the area of ​​the contact surface 2a can be increased by about two times, thereby reducing the electrical resistance between the first conductive film 2 and the conductive adhesive (F).

[0078] In this embodiment, the hole rows (8A1, 8A2), (8B1, 8B2) are formed in multiple rows along the longitudinal direction L. The multiple hole rows (8A1, 8A2), (8B1, 8B2) are formed at predetermined intervals in the width direction H. The multiple island-shaped holes (8A-8A), (8B-8B) are arranged in parallel at predetermined intervals in the longitudinal direction L. More specifically, a pair of scribe regions δA, δB made of island-shaped regions are provided at both ends of the solar cell 100 in the width direction H. In the example shown in FIG. 7 , multiple rows (two rows in this example) of hole rows (8A1, 8A2) are formed in the scribe region δA at one end in the width direction H, and multiple rows (two rows in this example) of hole rows (8B1, 8B2) are formed in the scribe region δB at the other end in the width direction H. In this example, the number of hole rows (8A1, 8A2), (8B1, 8B2) in each scribe region δA, δB is two, but it may be three or more. Also, in this embodiment, holes 8B to 8B may be formed alternately in the longitudinal direction L in at least one of the pair of scribe regions (δA, δB) consisting of island regions (in this example, the scribe region δB at the other end in the width direction H).

[0079] In addition, when the inner scribe regions δA1 and δB1, which are the inner scribe regions in the width direction H, are island-shaped regions, it is possible to pass current through parts of the first conductive film 2 other than the island regions (see arrows MA and MB in Figure 7), thereby allowing current to also pass through the end scribe regions δA2 and δB2, which are the scribe regions at the ends in the width direction H.

[0080] Fourth Embodiment FIG. 8 is a plan view schematically illustrating an example of a solar cell 100 according to a fourth embodiment.

[0081] In solar cell 100 according to the present embodiment, holes 8A, 8B form hole rows (8A1, 8A2), (8B1, 8B2) consisting of multiple rows of holes. In the multiple hole rows (8A1, 8A2), (8B1, 8B2), end hole rows 8A2, 8B2 in the width direction H are made up of linear holes, and hole rows 8A1, 8B1 on the inside of end hole rows 8A2, 8B2 made up of linear holes in the width direction H are made up of a plurality of island-like holes. In the manufacturing method for solar cell 100 according to the present embodiment, in second step S2, end hole rows 8A2, 8B2 made up of linear holes are formed at the ends of solar cell 100 in the width direction H, and inner hole rows 8A1, 8B1 made up of a plurality of island-like holes are formed on the inside of end hole rows 8A2, 8B2 in the width direction H of solar cell 100.

[0082] In this way, the hole rows 8A2, 8B2 at the ends in the width direction H are made up of straight holes, and the hole rows 8A1, 8B1 on the inside of the hole rows 8A2, 8B2 at the ends in the width direction H are made up of island-shaped holes, thereby preventing current from flowing easily to the ends in the width direction H.

[0083] In this embodiment, the plurality of island-shaped holes (8A-8A), (8B-8B) are arranged in parallel at predetermined intervals in the longitudinal direction L. In detail, the scribe regions δA, δB combine end scribe regions δA2, δB2 that constitute end hole rows 8A2, 8B2 [first embodiment (see FIG. 5)] and inner scribe regions δA1, δB1 that constitute inner hole rows 8A1, 8B1 [second and third embodiments (see FIGS. 6 and 7)].

[0084] Note that if there are scribe regions that form linear holes, it is more difficult for current to flow to the ends in the width direction H. For this reason, as shown in Figure 8, in the width direction H, it is preferable that the end scribe regions δA2, δB2 that form the hole rows (8A2, 8B2) that are made up of linear holes are located in regions that are closer to the ends of solar cell 100 than the inner scribe regions δA1, δB1 that form the hole rows (8A1, 8B1) that are made up of a plurality of island-shaped holes.

[0085] Fifth Embodiment FIG. 9 is a plan view schematically illustrating an example of a solar cell 100 according to a fifth embodiment.

[0086] In solar cell 100 according to this embodiment, at least one of holes 8A, 8B (in this example, hole 8A on one side H1 in width direction H) is a plurality of substantially rectangular holes extending diagonally with respect to longitudinal direction L. The plurality of substantially rectangular holes extending diagonally are arranged side by side at predetermined intervals in longitudinal direction L. In the manufacturing method for solar cell 100 according to this embodiment, in second step S2, a plurality of substantially rectangular holes 8A extending diagonally with respect to longitudinal direction L are formed at predetermined intervals in longitudinal direction L.

[0087] In solar cell 100 according to this embodiment, at least one of holes 8A, 8B (in this example, hole 8B on the other side H2 in width direction H) is a plurality of holes having a substantially rectangular shape along width direction H. The plurality of substantially rectangular holes along width direction H are arranged in parallel at predetermined intervals in longitudinal direction L. In the manufacturing method for solar cell 100 according to this embodiment, in second step S2, a plurality of substantially rectangular holes 8B along width direction H are formed at predetermined intervals in longitudinal direction L.

[0088] In this embodiment, the area of ​​the contact surface 2a in the width direction H can be increased, thereby reducing the electrical resistance between the first conductive film 2 and the conductive adhesive (F). Moreover, the holes 8A, 8B can be made wider than the wiring regions βA, βB, allowing for more flexibility in positioning the wiring materials (6, 7) when attaching them.

[0089] Although rectangular holes are exemplified in the first to fifth embodiments, the rectangular holes may have rounded corners (arc-shaped corners).

[0090] Sixth Embodiment Fig. 10A is a plan view schematically illustrating another example of a solar cell 100 according to a sixth embodiment. Fig. 10B is a cross-sectional view of the solar cell 100 according to the sixth embodiment taken along line B-B shown in Fig. 10A. Note that holes 8A and 8B have the same configuration, and are therefore shown in a single view in Fig. 10B and in Figs. 11 to 15C described below.

[0091] In solar cell 100 according to the present embodiment, holes 8A, 8B have a depth that reaches at least to base 1. In the method for manufacturing solar cell 100 according to the present embodiment, in second step S2, holes 8A, 8B are formed with a depth that reaches at least to base 1.

[0092] In the scribe regions δA and δB, holes 8A and 8B8 of the same width are cut in the first charge transport layer 3 (electron transport layer) and the first conductive film 2 (transparent conductive film).

[0093] The exposed regions φA and φB on one side and the other side in the width direction H of the first conductive film 2 are exposed on the side surfaces of one side H1 and the other side H2 in the width direction H of the first conductive film 2, respectively, and extend along the depth direction D.

[0094] In the scribe region δA on one side H1 in the width direction H of the first embodiment (see Figure 5) and the end scribe region δA2 on one side H1 in the width direction H of the fourth embodiment (see Figure 8), the region where current mainly flows on the contact surface 2a of the first conductive film 2 with the conductive material F is the exposed region φB on the other side H2 in the width direction H shown in Figure 10B.

[0095] In contrast, in the scribe region δB on the other side H2 in the width direction H of the first embodiment, and the end scribe region δB2 on the other side H2 in the width direction H of the fourth embodiment, the region on the contact surface 2a where current mainly flows is the exposed region φA on one side H1 in the width direction H shown in Figure 10B.

[0096] Furthermore, in the scribe regions δA, δB of the second and third embodiments (see Figures 6 and 7) and the inner scribe regions δA1, δB1 of the fourth embodiment (see Figure 8), current flows through both exposed regions φA, φB on both sides in the width direction H shown in Figure 10B.

[0097] 10B, the depth of the holes 8A, 8B formed in the scribe regions δA, δB is the depth to the surface 1a (interface) of the base 1 facing the first conductive film 2, but they may be deeper, i.e., cut partway through the base 1. This also applies to the ninth and tenth embodiments (see FIGS. 13 and 14) described below.

[0098] Here, the term "exposed region" in the present disclosure refers to a region in which the first conductive film 2 is exposed when no conductive material F is provided. This also applies to the seventh to eleventh embodiments (see FIGS. 11 to 15C) described later.

[0099] Seventh Embodiment FIG. 11 is a cross-sectional view schematically illustrating an example of a solar cell 100 according to a seventh embodiment.

[0100] In solar cell 100 according to the present embodiment, holes 8A and 8B have a depth reaching to surface 2b (interface) of first conductive film 2 facing first charge transport layer 3. In the method for manufacturing solar cell 100 according to the present embodiment, in second step S2, holes 8A and 8B are formed with a depth reaching to surface 2b of first conductive film 2 facing first charge transport layer 3. In scribe regions δA and δB, holes 8A and 8B are cut to reach surface 2b of first conductive film 2 facing first charge transport layer 3.

[0101] The exposed region φC of the first conductive film 2 is exposed at the surface 2b of the first conductive film 2 facing the first charge transport layer 3, and extends along the width direction H. In this structure, as the width W of the scribe regions δA and δB is increased, the area of ​​the contact surface 2a of the first conductive film 2 with the conductive material F can be increased, and the electrical resistance between the first conductive film 2 and the conductive adhesive (F) can be reduced accordingly.

[0102] Eighth Embodiment FIG. 12 is a cross-sectional view schematically illustrating an example of a solar cell 100 according to an eighth embodiment.

[0103] In solar cell 100 according to the present embodiment, holes 8A and 8B are deep enough to reach partway through first conductive film 2. In the method for manufacturing solar cell 100 according to the present embodiment, in second step S2, holes 8A and 8B are formed to reach partway through first conductive film 2. In scribe regions δA and δB, holes 8A and 8B are cut partway through first conductive film 2.

[0104] The exposed region φC on the bottom side of the first conductive film 2 is exposed on the bottom surface of the first conductive film 2 and on the side surfaces on one side H1 and the other side H2 in the width direction H, and extends along the width direction H and the depth direction D. In this structure, the area of ​​the contact surface 2a of the first conductive film 2 with the conductive material F can be made larger than in the structure of the seventh embodiment (see FIG. 11 ) by the amount that penetrates into the first conductive film 2, and the electrical resistance between the first conductive film 2 and the conductive adhesive (F) can be reduced accordingly.

[0105] Ninth Embodiment FIG. 13 is a cross-sectional view schematically illustrating an example of a solar cell 100 according to a ninth embodiment.

[0106] In solar cell 100 according to the present embodiment, holes 8A and 8B are deeper than surface 2b of first conductive film 2 facing first charge transport layer 3, and are tapered holes that widen toward the side opposite base 1. In the method for manufacturing solar cell 100 according to the present embodiment, second step S2 forms tapered holes that are deeper than first conductive film 2 and widen toward the side opposite base 1. In scribe regions δA and δB, holes 8A and 8B that are tapered in cross section are machined (mechanically machined in this example).

[0107] The exposed regions φA and φB of the first conductive film 2 are exposed at tapered surfaces on one side H1 and the other side H2 in the width direction H, respectively, and extend obliquely relative to the depth direction D.

[0108] In this way, by forming the holes 8A, 8B in a tapered shape that widens toward the opposite side from the base 1, the exposed areas φA, φB where the first conductive film 2 is exposed, and therefore the contact surface 2a of the first conductive film 2 with the conductive material F, can be made larger compared to the structure of the sixth embodiment (see Figures 10A and 10B), and accordingly, more power can be extracted from the first conductive film 2.

[0109] The structure of the ninth embodiment may be combined with the structure of the eighth embodiment (see FIG. 12).

[0110] Tenth Embodiment FIG. 14 is a cross-sectional view schematically illustrating an example of a solar cell 100 according to a tenth embodiment.

[0111] In solar cell 100 according to the present embodiment, holes 8A and 8B are holes deeper than surface 2b of first conductive film 2 facing first charge transport layer 3, and a width W1 (W) of a depth portion corresponding to first conductive film 2 is smaller than a width W2 (W) of a depth portion corresponding to first charge transport layer 3 (W2>W1). In the manufacturing method for solar cell 100 according to the present embodiment, second step S2 forms holes deeper than first conductive film 2, and the width W1 of the hole in the first conductive film 2 is smaller than the width W2 of the hole in the first charge transport layer 3. In scribe regions δA and δB, holes 8A and 8B8 are cut to have a stepped shape in cross section.

[0112] The exposed regions φA1, φB1 and the exposed regions φA2, φB2 of the first conductive film 2 are aligned along the depth direction D and the width direction H, respectively, and the first conductive film 2 is exposed on one side H1 and the other side H2 in the width direction H. Here, the exposed regions of the first conductive film 2 are the exposed regions φA1, φB1 along the depth direction D and the exposed regions φA2, φB2 along the width direction H.

[0113] In this way, the structure of the tenth embodiment can increase the exposed areas φA, φB where the first conductive film 2 is exposed, and therefore the contact surface 2a of the first conductive film 2 with the conductive material F, compared to the structure of the sixth embodiment (see Figures 10A and 10B), and accordingly, can extract more power from the first conductive film 2.

[0114] 14 , the contact surfaces 2 a of the exposed regions φA2 and φB2 along the width direction H with the conductive material F are surfaces 2 b of the first conductive film 2 facing the first charge transport layer 3. However, this is not limitative, and the contact surfaces 2 a of the exposed regions φA2 and φB2 along the width direction H may be located midway through the first conductive film 2 in the depth direction D.

[0115] 15A to 15C are cross-sectional views each schematically showing an example, another example, and yet another example of a solar cell 100 according to an eleventh embodiment. In Fig. 15A to 15C, of ​​the scribe regions δA and δB on both sides H1 and H2 in the width direction H, the common configuration of the scribe region δA on one side H1 and the scribe region δB on the other side H2 is represented by a symbol without quotation marks, and the configuration unique to the scribe region δB on the other side H2 is the same as the configuration obtained by flipping the scribe region δA shown in Fig. 15A to 15C left and right, and is represented by a symbol with quotation marks.

[0116] In the solar cell 100 according to this embodiment, the holes 8A, 8B have at least two portions λ of different depths. Of the at least two portions λ of different depths, at least one portion λ1 is deeper than the surface 2b of the first conductive film 2 facing the first charge transport layer 3. In the manufacturing method for the solar cell 100 according to this embodiment, in the second step S2, holes 8A, 8B are formed, each having at least two portions λ of different depths (step-like portions in this example), and in which at least one portion λ1 of the at least two portions λ of different depths is deeper than the surface 2b of the first conductive film 2 facing the first charge transport layer 3. In this example, the portion λ1 deeper than the surface 2b of the first conductive film 2 facing the first charge transport layer 3 includes a portion λ1a deeper than the surface 1a of the base 1 facing the first conductive film 2. The cutting conditions (cutting strength) of the cutting process are gradually changed so that the small scribe regions T(1) to T(n) (n is an integer of 2 or more; in this example, n = 7) gradually become deeper from the inside to the ends in the width direction H. Here, n is a value that increases in the direction of width H from the end of the other side H2 in the case of the scribe area δA on one side H1, and in the case of the scribe area δB on the other side H2, it is a value that increases in the direction of width H from the end of the one side H1. For example, when performing cutting by mechanical processing or laser processing, if the cutting strength is increased in stages, the relative position with respect to the workpiece and the output power of the laser light are set each time cutting is performed so that the cutting dimension (digging amount) of the workpiece increases in stages.

[0117] By doing so, small scribe regions T(1) to T(n) that become deeper stepwise from the inside toward the ends in the width direction H can be easily formed.

[0118] In the scribe regions δA and δB, at least two small scribe regions T(1) to T(n) of different depths are cut adjacent to each other. In the portion λ of the scribe region δA where at least two depths are different, the depths of the small scribe regions T(1) to T(n) become deeper the closer they are to the end of one side H1 of the solar cell 100 in the width direction H. In addition, in the portion λ of the scribe region δB where at least two depths are different, the depths of the small scribe regions T(1) to T(n) become deeper the closer they are to the end of the other side H2 of the solar cell 100 in the width direction H.

[0119] Furthermore, in solar cell 100 according to the present embodiment, holes 8A, 8B are deepest on the side closer to the end of solar cell 100 in width direction H. In the method for manufacturing solar cell 100 according to the present embodiment, in second step S2, holes 8A, 8B are formed so that they are deepest on the side closer to the end of solar cell 100 in width direction H.

[0120] 15A to 15C, among the small scribe regions T(1) to T(n), at least some [for example, up to n=j (j is an integer from 2 to n, in this example j=5)] of adjacent small scribe regions [T(1), T(2)], ..., [T(j-1), T(j)] are spaced apart, and the remaining portions [for example, small scribe regions T(j) to T(n)] are connected to each other (joined). In this way, among the small scribe regions T(1) to T(n), some or all of the adjacent small scribe regions may be adjacent to each other, or all of the small scribe regions may be spaced apart.

[0121] The overall width W of the scribe regions δA and δB is set to be approximately the same as that of the other examples described above.

[0122] The scribe regions δA and δB as shown in Figures 15A and 15B can be suitably used when forming a hole 8A in a linear manner extending to the end face of one side L1 and the end face of the other side L2 in the longitudinal direction L of the base 1, as in the scribe region δA on one side H1 in the width direction H in the first embodiment (see Figure 5).

[0123] That is, when the holes 8A are formed linearly from the end face on one side L1 to the end face on the other side L2 in the longitudinal direction L of the base 1, as described above, the region where current mainly flows on the contact surface 2a of the first conductive film 2 with the conductive material F is the exposed region φB on the other side H2 in the width direction H. In this regard, in the scribe regions δA and δB shown in Figures 15A and 15B, the exposed region φB on the other side H2 of the first conductive film 2, which has a larger area of ​​the contact surface 2a than the exposed region φA on one side H1, becomes the region where current mainly flows on the contact surface 2a, making it easier for current to flow on the contact surface 2a.

[0124] The scribe regions δA and δB shown in Figure 15B show an example in which the depths are shallower than the scribe regions δA and δB shown in Figure 15 A. As the depths of the scribe regions δA and δB become shallower, the contact surfaces 2a in the scribe regions δA and δB shown in Figure 15B shift to one side H1 in the width direction H relative to the contact surfaces 2a in the scribe regions δA and δB shown in Figure 15A.

[0125] When the holes 8A are formed linearly from the end face of one side L1 to the end face of the other side L2 in the longitudinal direction L of the base 1, the exposed region φB on the other side H2 becomes the region on the contact surface 2a through which current mainly flows. The exposed region φB shown in Figure 15B is shifted toward one side H1 in the width direction H from the exposed region φB shown in Figure 15A.

[0126] The scribe regions δA and δB shown in Figure 15C show an example in which the depths are deeper than the scribe regions δA and δB shown in Figure 15 A. As the depths of the scribe regions δA and δB increase, the contact surfaces 2a in the scribe regions δA and δB shown in Figure 15C shift toward the other side H2 in the width direction H relative to the contact surfaces 2a in the scribe regions δA and δB shown in Figure 15A.

[0127] When the holes 8A are formed linearly from the end face of one side L1 to the end face of the other side L2 in the longitudinal direction L of the base 1, the exposed region φB on the other side H2 becomes the region on the contact surface 2a through which current mainly flows. The exposed region φB shown in Figure 15C is shifted toward the other side H2 in the width direction H from the exposed region φB shown in Figure 15A.

[0128] Due to variations in the manufacturing conditions of the solar cell 100, such as variations in the thickness of one or more of the base 1, the first conductive film 2, and the first charge transport layer 3, or variations in the hardness of one or both of the first conductive film 2 and the first charge transport layer 3, the depth of the scribe regions δA and δB may be shallower or deeper than the target depth. Even in such cases, in the solar cell 100 according to the eleventh embodiment, the contact surface 2 a shifts to one side H1 or the other side H2 in the width direction H, and the contact surface 2 a is present in either of these portions. As a result, the solar cell 100 according to the eleventh embodiment can stably ensure electrical continuity between the first conductive film 2 and the wiring members (the first wiring member 6 and the second wiring member 7) without being affected by variations in the manufacturing conditions.

[0129] Other Embodiments In each of the first to fifth embodiments, the holes 8A formed at the end of one side H1 in the width direction H and the holes 8B formed at the end of the other side H2 are different in configuration. Accordingly, the first to fifth embodiments illustrate ten different configurations of holes. In a given solar cell 100, any one of these ten types of holes may be used for both the hole 8A at the end of one side H1 in the width direction H and the hole 8B at the end of the other side H2 in the width direction H. Furthermore, any two of these ten types of holes may be used in combination. For example, any two of these ten types of holes may be used for the hole 8A at the end of one side H1 in the width direction H and the hole 8B at the end of the other side H2 in the width direction H, respectively.

[0130] In the sixth to eleventh embodiments, six different types of holes are shown. Any two of these six types of holes may be used in combination in a given solar cell 100. For example, any two of these six types of holes may be used for the hole 8A at the end on one side H1 in the width direction H and the hole 8B at the end on the other side H2.

[0131] In the first to fifth embodiments, ten different hole shapes are shown in a plan view. In the sixth to eleventh embodiments, six different hole shapes are shown in a cross-sectional view. A hole may be formed by combining any one of these ten different hole shapes in a plan view with any one of the six different hole shapes in a cross-sectional view. For example, a hole may be formed by combining the shape of the hole 8B at the end of the other side H2 in the width direction H of the third embodiment in a plan view with the shape of the hole 8A of the tenth embodiment in a cross-sectional view.

[0132] The present disclosure is not limited to the above-described embodiments, but can be implemented in various other forms. Therefore, the embodiments are merely examples in all respects and should not be interpreted as being limiting. The scope of the present disclosure is defined by the claims and is not bound by the text of the specification. Furthermore, all modifications and variations within the equivalent scope of the claims are within the scope of the present disclosure.

[0133] This application claims priority from Japanese Patent Application No. 2024-26671, filed on February 26, 2024, the entire contents of which are incorporated herein by reference.

[0134] The present disclosure relates to a solar cell in which one or more photoelectric conversion elements are formed on a substrate having a first conductive film and a first charge transport layer arranged in this order on one side of the substrate, and is particularly applicable to applications for effectively preventing a decrease in the power that can be extracted from the solar cell.

[0135] 1 Base body 1a Opposing surface 10 Photoelectric conversion element (solar cell) 100 Solar cell 2 First conductive film 2a Contact surface 2b Opposing surface 3 First charge transport layer 4 Photoelectric conversion layer 40 Insulating layer 5 Second conductive film 6 First wiring material 7 Second wiring material 8A First hole 8A1 Inner hole row 8A2 End hole row 8B Second hole 8B1 Inner hole row 8B2 End hole row 9 Separation groove D Depth direction F Conductive material H Width direction L Longitudinal direction Q Perovskite material liquid S1 First step S2 Second step S3 Third step S4 Fourth step T Small scribe area W Hole width d1 Wiring area width d2 Wiring material width βA Wiring area βB Wiring area γ1 Element formation area (cell formation area) γ2 Busbar attachment region δA Scribe region δA1 Inner scribe region δA2 End scribe region δB Scribe region δB1 Inner scribe region δB2 End scribe region λ At least two portions with different depths φA Exposed region on one side of the first conductive film φA1 Exposed region along the depth direction of the first conductive film φA2 Exposed region along the width direction of the first conductive film φB Exposed region on the other side of the first conductive film φB1 Exposed region along the depth direction of the first conductive film φB2 Exposed region along the width direction of the first conductive film φC Exposed region on the bottom side of the first conductive film

Claims

1. A solar cell having one or more photoelectric conversion elements formed on a substrate having a first conductive film and a first charge transport layer arranged in this order on one side of the substrate, the solar cell having a wiring region for connecting wiring material to the first conductive film, and one or more holes formed in the first charge transport layer in the wiring region, the one or more holes including a hole deep enough to reach at least the first conductive film.

2. The solar cell according to claim 1, wherein the holes are linear holes.

3. The solar cell according to claim 1, wherein the holes are island-shaped holes.

4. The solar cell according to claim 1, wherein the holes form a hole row consisting of multiple rows of island-shaped holes.

5. The solar cell according to claim 1, wherein the holes form a hole row consisting of multiple rows of holes, and the multiple hole rows are such that the hole row at the end in a width direction perpendicular to the longitudinal direction of the wiring region is made up of straight holes, and the hole row inside the end hole row consisting of straight holes in the width direction is made up of multiple island-shaped holes.

6. The solar cell according to any one of claims 1 to 5, wherein the holes are holes having a depth that reaches at least the base.

7. The solar cell according to any one of claims 1 to 5, wherein the holes have a depth that reaches partway through the first conductive film.

8. The solar cell according to any one of claims 1 to 5, wherein the holes have a depth reaching the surface of the first conductive film facing the first charge transport layer.

9. A solar cell described in any one of claims 1 to 5, wherein the hole is deeper than the surface of the first conductive film facing the first charge transport layer and is a tapered hole widening toward the opposite side from the substrate.

10. A solar cell described in any one of claims 1 to 5, wherein the hole is deeper than the surface of the first conductive film facing the first charge transport layer, and the width of the deep portion corresponding to the first conductive film is smaller than the width of the deep portion corresponding to the first charge transport layer.

11. A solar cell described in any one of claims 1 to 5, wherein the hole has at least two portions with different depths, and the depth of at least one of the at least two portions with different depths is deeper than the surface of the first conductive film facing the first charge transport layer.

12. The solar cell according to claim 11, wherein the hole has the deepest depth on the side closer to the end of the solar cell in the width direction perpendicular to the longitudinal direction of the wiring region.

13. A solar cell according to any one of claims 1 to 12, wherein the photoelectric conversion element has a photoelectric conversion layer and a second conductive film formed in this order on the first charge transport layer, and the photoelectric conversion layer has a light absorption layer containing perovskite.

14. A solar cell according to any one of claims 1 to 13, wherein a plurality of the photoelectric conversion elements are formed on the substrate.

15. A method for manufacturing a solar cell according to any one of claims 1 to 14, comprising: a first step of forming the first charge transport layer on the first conductive film formed on one surface of the substrate; and a second step of forming the one or more holes in the first charge transport layer in the wiring region.

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