Solar cell, solar cell string, and solar cell module

Abstract

Provided is a solar cell 1, comprising: a semiconductor substrate 11; a first semiconductor layer 13 laminated on the back side of the semiconductor substrate 11; a back side connection electrode 15 arranged on the back side of the first semiconductor layer 13; a second semiconductor layer 17 laminated on the front side of the semiconductor substrate 11; a junction layer 18 laminated on the front side of the second semiconductor layer 17; an intermediate transparent electrode layer 19 laminated on the surface of the junction layer 18; a surface side photoelectric conversion layer 20 that contains a perovskite compound and is laminated on the front side of the intermediate transparent electrode layer 19; a front side transparent electrode layer 21 laminated on the front side of the front side photoelectric conversion layer 20; and a front side connection electrode 22 arranged on the surface of the front side transparent electrode layer 21. At least a part of an outer edge of the intermediate transparent electrode layer 19 is retreated inward in a plan view from an outer edge of the joining layer 18 so as to bring the front side photoelectric conversion layer 20 into contact with an end part of the joining layer 18.

Description

Solar cell, solar cell string and solar cell module

[0001] The present invention relates to a solar cell, a solar cell string, and a solar cell module.

[0002] A solar cell module is known in which a solar cell string is sealed, with a plurality of solar cells having electrodes on the front and back surfaces connected in series with an interconnector (see, for example, Patent Document 1). Also known is a tandem solar cell having two photoelectric conversion layers with different absorption wavelengths and an intermediate transparent electrode layer connecting the two photoelectric conversion layers in order to improve photoelectric conversion efficiency (see, for example, Patent Document 2).

[0003] International Publication No. WO 2013 / 121549 International Publication No. WO 2008 / 099524

[0004] The layers of a solar cell are often laminated using vacuum film-forming techniques, but layers can also be laminated by coating. For example, photovoltaic layers containing perovskite compounds are often formed by coating. Because it is difficult to laminate materials with a uniform thickness all the way to the edges of the substrate using coating, solar cells with photovoltaic layers formed by coating may have a thin photovoltaic layer at the periphery of the solar cell, or the photovoltaic layer may not be laminated all the way to the periphery of the solar cell. This may result in the edge of the lower transparent electrode layer coming into contact with the interconnector connecting the solar cell, causing a short circuit.

[0005] Therefore, an object of the present invention is to provide a solar cell, a solar cell string, and a solar cell module that can suppress short circuits caused by interconnectors.

[0006] a first semiconductor layer stacked on a back side of the semiconductor substrate; a plurality of back side connection electrodes disposed on the back side of the first semiconductor layer; a second semiconductor layer stacked on a front side of the semiconductor substrate; a bonding layer stacked on the front side of the second semiconductor layer; an intermediate transparent electrode layer stacked on the surface of the bonding layer; a front side photoelectric conversion layer containing a perovskite compound stacked on the front side of the intermediate transparent electrode layer; a front side transparent electrode layer stacked on the front side of the front side photoelectric conversion layer; and a plurality of front side connection electrodes disposed on the surface of the front side transparent electrode layer, wherein at least a portion of the outer edge of the intermediate transparent electrode layer is recessed inward in a planar view from the outer edge of the bonding layer so that the front side photoelectric conversion layer contacts an end of the bonding layer.

[0007] A solar cell string according to one embodiment of the present invention comprises a plurality of the above-described solar cells arranged in a row, and a plurality of interconnectors that respectively connect the back side connection electrode of one of the solar cells on one side of two adjacent solar cells to the back side connection electrode of the solar cell on the other side, and the outer edge of the intermediate transparent electrode layer is recessed inward from the outer edge of the bonding layer in the region where the interconnectors intersect in a planar view.

[0008] A solar cell module according to one embodiment of the present invention comprises the above-described solar cell string, a surface protective material covering the front side of the solar cell string, a back protective material covering the back side of the solar cell string, and a sealing material filled in the space around the solar cell string between the surface protective material and the back protective material.

[0009] In the solar cell module described above, the sealing material may be made of a non-crosslinked resin.

[0010] According to the present invention, it is possible to provide a solar cell, a solar cell string, and a solar cell module that can suppress short circuits caused by interconnectors.

[0011] Fig. 3 is a schematic plan view showing the configuration of a solar cell according to one embodiment of the present invention. Fig. 4 is a schematic cross-sectional view taken along line X-X of the solar cell of Fig. 1. Fig. 5 is a schematic plan view of a solar cell module having the solar cell of Fig. 1. Fig. 6 is a schematic cross-sectional view taken along line Y-Y of the solar cell module of Fig. 3. Fig. 7 is a graph showing the output of a solar cell according to an example of the present invention.

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1 is a schematic cross-sectional view showing the configuration of a solar cell 1 according to a first embodiment of the present invention. Fig. 2 is a schematic cross-sectional view of the solar cell 1. For convenience, the dimensions of various components in the drawings have been adjusted for clarity.

[0013] The solar cell 1 includes a semiconductor substrate 11 made of a semiconductor substrate, a first passivation layer 12 laminated over the entire back side of the semiconductor substrate 11, a first semiconductor layer 13 laminated over the entire back side of the first passivation layer 12, a back-side transparent electrode layer 14 laminated over the entire back side of the first semiconductor layer 13, a back-side connection electrode 15 disposed on the back side of the back-side transparent electrode layer 14, a second passivation layer 16 laminated over the entire surface of the semiconductor substrate 11, and a second passivation layer 17 laminated over the entire surface of the second passivation layer 16. The semiconductor device comprises a semiconductor layer (17), a bonding layer (18) laminated over the entire surface of the second semiconductor layer (17), an intermediate transparent electrode layer (19) laminated over the surface of the bonding layer (18) leaving at least a portion of the outer edge of the bonding layer (18), a front-side photoelectric conversion layer (20) laminated over the entire surface of the intermediate transparent electrode layer (19) and the bonding layer (18) exposed from the intermediate transparent electrode layer (19) and containing a perovskite compound, a front-side transparent electrode layer (21) laminated over the entire surface of the front-side photoelectric conversion layer (20), and a front-side connection electrode (22) disposed on the surface of the front-side transparent electrode layer (21).

[0014] The semiconductor substrate 11 is a photoelectric conversion substrate that absorbs incident light and generates photocarriers (electrons and holes). The semiconductor substrate 11 can be formed of a crystalline silicon material such as single crystal silicon or polycrystalline silicon. It may also be formed of other semiconductor materials such as gallium arsenide (GaAs). The semiconductor substrate 11 can be, for example, an n-type semiconductor substrate in which a crystalline silicon material is doped with an n-type dopant. Examples of n-type dopants include phosphorus (P). The semiconductor substrate 11 can also be a p-type semiconductor substrate in which a crystalline silicon material is doped with a p-type dopant. Examples of p-type dopants include boron (B). By using crystalline silicon as the material for the semiconductor substrate 11, dark current is relatively small, and relatively high output (stable output regardless of illuminance) can be obtained even when the intensity of incident light is low. The semiconductor substrate 11 may have a pyramidal micro-concave structure, known as a texture structure, on its main surface to improve the light incidence rate.

[0015] The first passivation layer 12 forms a depletion layer to suppress carrier recombination on the back side of the semiconductor substrate 11. The first passivation layer 12 can be formed, for example, from intrinsic semiconductor silicon (i-type amorphous silicon), silicon oxide (SiO), or the like. The first passivation layer 12 can be formed, for example, by a film formation technique such as CVD or PVD. The lower limit of the thickness of the first passivation layer 12 is preferably 0.5 nm, more preferably 1.0 nm. On the other hand, the upper limit of the thickness of the first passivation layer 12 is preferably 50 nm, more preferably 30 nm. By setting the thickness of the first passivation layer 12 at or above the lower limit, pinholes in the first passivation layer 12 can be prevented, effectively suppressing carrier recombination. Furthermore, by setting the thickness of the first passivation layer 12 at or below the upper limit, the internal resistance of the first passivation layer 12 can be reduced, thereby improving the photoelectric conversion efficiency of the solar cell 1.

[0016] The first semiconductor layer 13 is stacked on the back surface side of the semiconductor substrate 11 via the first passivation layer 12. The first semiconductor layer 13 is a semiconductor layer having a first conductivity and selectively extracts only photocarriers of one polarity among photocarriers generated in the semiconductor substrate 11. The first semiconductor layer 13 may be formed from a thin film of amorphous silicon and may contain the same dopant as the semiconductor substrate 11 described above at a higher content than the semiconductor substrate 11. The first semiconductor layer 13 may be formed by a film formation technique such as CVD or PVD. The lower limit of the thickness of the first semiconductor layer 13 is preferably 0.5 nm, more preferably 1.0 nm. On the other hand, the upper limit of the thickness of the first semiconductor layer 13 is preferably 50 nm, more preferably 30 nm. By making the thickness of the first semiconductor layer 13 equal to or greater than the lower limit, carriers generated in the semiconductor substrate 11 can be appropriately collected. Furthermore, by setting the thickness of the first semiconductor layer 13 to be equal to or less than the upper limit, the internal resistance of the first semiconductor layer 13 can be reduced, and the photoelectric conversion efficiency of the solar cell 1 can be improved.

[0017] The back-side transparent electrode layer 14 is a conductive layer for collecting current from the first semiconductor layer 13 and transmitting charges to the back-side connection electrode 15. The back-side transparent electrode layer 14 can be formed from a transparent conductive oxide (TCO), such as indium oxide, tin oxide, zinc oxide, titanium oxide, or a composite oxide thereof. Among these, ITO (indium tin oxide), which is indium oxide doped with tin, is preferred. The back-side transparent electrode layer 14 can be formed by a film formation technique such as CVD or PVD. The lower limit of the thickness of the back-side transparent electrode layer 14 is preferably 10 nm, more preferably 20 nm. Meanwhile, the upper limit of the thickness of the back-side transparent electrode layer 14 is preferably 100 nm, more preferably 80 nm. By making the thickness of the back-side transparent electrode layer 14 equal to or greater than the lower limit, the internal resistance of the back-side transparent electrode layer 14 can be reduced, thereby improving the photoelectric conversion efficiency of the solar cell 1. Furthermore, by setting the thickness of the back transparent electrode layer 14 to the above upper limit or less, it is possible to prevent the manufacturing cost of the solar cell 1 from increasing unnecessarily.

[0018] The back-side connection electrode 15 is disposed on the back side of the first semiconductor layer 13 via the back-side transparent electrode layer 14. The back-side connection electrode 15 is a connection terminal to which the interconnector 2 (described later) is connected in order to output the charge extracted by the first semiconductor layer 13 to the outside. The back-side connection electrodes 15 may be arranged in a matrix. The back-side connection electrodes 15 may be formed, for example, from a conductive paste containing metal particles and a binder. Examples of the material for the metal particles include silver, copper, and nickel. Examples of the binder include resins such as epoxy resins, and thermosetting resin compositions containing a crosslinking agent that is activated by heating are particularly preferred. The back-side connection electrode 15 may also have a multilayer structure including, for example, a layer that improves adhesion to the back-side transparent electrode layer 14.

[0019] The second passivation layer 16 is a layer that suppresses carrier recombination, similar to the first passivation layer 12 .

[0020] The second semiconductor layer 17 selectively extracts carriers having a polarity different from that of the first semiconductor layer 13. The second semiconductor layer 17 can be formed from a thin film of amorphous silicon having a dopant type different from that of the first semiconductor layer 13. The method of forming the second semiconductor layer 17, its thickness, etc. are the same as those of the first semiconductor layer 13.

[0021] The bonding layer 18 improves adhesion between the second semiconductor layer 17 and the intermediate transparent electrode layer 19 and prevents short circuits by covering the surface of the second semiconductor layer 17. The bonding layer 18 has high adhesion to the second semiconductor layer 17 and the intermediate transparent electrode layer 19 and can be formed from a relatively high-resistance material, such as SiOx. The bonding layer 18 can be formed by a film formation technique, such as CVD or PVD. The lower limit of the thickness of the bonding layer 18 is preferably 0.5 nm, more preferably 1.0 nm. Meanwhile, the upper limit of the thickness of the bonding layer 18 is preferably 20 nm, more preferably 10 nm. By setting the thickness of the bonding layer 18 at or above the lower limit, pinholes can be prevented from forming in the bonding layer 18. Furthermore, by setting the thickness of the bonding layer 18 at or below the upper limit, the internal resistance of the bonding layer 18 can be reduced, thereby improving the photoelectric conversion efficiency of the solar cell 1.

[0022] The intermediate transparent electrode layer 19 connects the back-side photoelectric conversion structure that extracts charges photoelectrically converted by the semiconductor substrate 11 with the front-side photoelectric conversion structure that extracts charges photoelectrically converted by the front-side photoelectric conversion layer 20. The intermediate transparent electrode layer 19 can be formed using a film formation technique such as CVD or PVD using the same material as the back-side transparent electrode layer 14. The lower limit of the thickness of the intermediate transparent electrode layer 19 is preferably 10 nm, more preferably 20 nm. Meanwhile, the upper limit of the thickness of the intermediate transparent electrode layer 19 is preferably 100 nm, more preferably 80 nm. By setting the thickness of the intermediate transparent electrode layer 19 at or above the lower limit, electrical connection between the back-side photoelectric conversion structure and the front-side photoelectric conversion structure can be ensured. Furthermore, by setting the thickness of the intermediate transparent electrode layer 19 at or below the upper limit, the internal resistance of the intermediate transparent electrode layer 19 can be reduced, thereby improving the photoelectric conversion efficiency of the solar cell 1.

[0023] At least a portion of the outer edge of the intermediate transparent electrode layer 19 is recessed inward in plan view from the outer edge of the bonding layer 18 so that the front-side photoelectric conversion layer 20 contacts the end of the bonding layer 18. More specifically, the outer edge of the intermediate transparent electrode layer 19 is recessed inward from the outer edge of the bonding layer 18 at least in the region where the interconnector 2 connected to the front-side connection electrode 22 intersects in plan view. This prevents the intermediate transparent electrode layer 19 from contacting the interconnector 2 and causing a short circuit. The intermediate transparent electrode layer 19 with a recessed outer edge can be formed by selectively depositing material using a mask or selectively removing it by etching using a mask.

[0024] The lower limit of the recession distance of the intermediate transparent electrode layer 19 from the bonding layer 18 is preferably 70 μm, more preferably 100 μm. On the other hand, the upper limit of the recession distance of the intermediate transparent electrode layer 19 from the bonding layer 18 is preferably 800 μm, more preferably 500 μm. By setting the recession distance of the intermediate transparent electrode layer 19 from the bonding layer 18 to the above lower limit or more, short circuits due to the interconnector 2 can be more reliably prevented. Furthermore, by setting the recession distance of the intermediate transparent electrode layer 19 from the bonding layer 18 to the above upper limit or less, a decrease in the photoelectric conversion efficiency of the solar cell 1 due to a reduction in the area of ​​the intermediate transparent electrode layer 19 can be suppressed.

[0025] The front-side photoelectric conversion layer 20 absorbs incident light to generate photocarriers. The perovskite compound contained in the front-side photoelectric conversion layer 20 includes an organic atom A including at least one of a monovalent organic ammonium ion and an amidinium ion, a metal atom B that generates a divalent metal ion, and a halogen atom X including at least one of an iodide ion I, a bromide ion Br, a chloride ion Cl, and a fluoride ion F, and the organic atom A is represented by the formula ABX. ３ Among them, when the front-side photoelectric conversion layer 20 is formed by a vapor deposition method (dry process), the organic atom A may be methylammonium MA (CH ３ NH ３ ) is preferred, the metal atom B is preferably lead Pb, and the halogen atom X is preferably at least one of iodide I, bromide ion Br, and chloride ion Cl.

[0026] Specifically, a preferred perovskite compound is methylammonium lead halide MAPbX. ３ (CH ３ NH ３ PbX ３ ), MAPbI ３ , MAPbBr ３ , MAPbCl ３ The halogen atom X may contain multiple types of atoms. Examples of perovskite compounds containing iodide I and other halogen atoms X include methylammonium lead iodide MAPbI. ｙ X （３－ｙ） (CH ３ NH ３ PbI ｙ X （３－ｙ） ), MAPbI ｙ Br （３－ｙ） , MAPbI ｙ Cl （３－ｙ） (where y is any positive integer).

[0027] The front-side photoelectric conversion layer 20 is made of a perovskite compound containing methylammonium lead halide (MAPbX ３ (CH ３ NH ３ PbX ３)), the front-side photoelectric conversion layer 20 is ２ For example, a perovskite compound can be formed by sequentially coating and drying a material containing methylammonium lead iodide (MAPbI) and a material containing methylammonium halide (MAPbI) to form a thin film of these materials at a reaction temperature. ｙ X （３－ｙ） (CH ３ NH ３ PbI ｙ X （３－ｙ） )), the front-side photoelectric conversion layer 20 can be formed, for example, by sequentially depositing a lead halide (PbX2) material and a methylammonium iodide (MAI) material and then reacting the resulting thin films at a reaction temperature. The front-side photoelectric conversion layer 20 can also be formed by a method such as a sol-gel method in which a perovskite compound is synthesized in a liquid-phase coating, or a coating method in which a solution containing a pre-synthesized perovskite compound is applied. The thickness of the front-side photoelectric conversion layer 20 depends on the material used, but is preferably 100 nm or more and 1000 nm or less in order to increase the light absorption rate while reducing the distance traveled by the generated charges.

[0028] The front-side transparent electrode layer 21 collects charges (photocarriers) of a polarity different from that of the back-side transparent electrode layer 14 from the front-side photoelectric conversion layer 20 and transmits them to the front-side connection electrode 22. The front-side transparent electrode layer 21 can be formed of the same material, by the same method, and to the same thickness as the back-side transparent electrode layer 14.

[0029] The front-side connection electrodes 22 are connection terminals to which the interconnector 2 is connected in order to output the charges collected by the front-side transparent electrode layer 21 to the outside. The front-side connection electrodes 22 can be arranged in a matrix. The front-side connection electrodes 22 can be made of the same material as the back-side connection electrodes 15.

[0030] As described above, in the solar cell 1 of this embodiment, the intermediate transparent electrode layer 19 is recessed from the bonding layer 18 , so that short circuits caused by the interconnector 2 coming into contact with the intermediate transparent electrode layer 19 can be prevented.

[0031] Next, a description will be given of a solar cell module 100 according to one embodiment of the present invention, which includes the solar cell 1. Fig. 3 is a schematic plan view of the solar cell module 100, and Fig. 4 is a schematic cross-sectional view of the solar cell module 100.

[0032] The solar cell module 100 comprises a plurality of solar cell strings 110, a surface protective material 120 covering the front side of the solar cell strings 110, a back protective material 130 covering the back side of the solar cell strings 110, and a sealing material 140 filled in the space around the solar cell strings 110 between the surface protective material 120 and the back protective material 130.

[0033] The solar cell string 110 includes solar cells 1 arranged in a row, and a plurality of interconnectors 2 that connect back-side connection electrodes 15 of one solar cell 1 of two adjacent solar cells 1 to front-side connection electrodes 22 of the other solar cell 1. The solar cell string 110 itself is an embodiment of the solar cell string according to the present invention.

[0034] In the solar cell module 100, the multiple solar cell strings 110 are electrically connected in series by connection wiring 111. Lead wiring 112 that extends outside the sealing material 140 and outputs power to the outside is connected to both ends of the connection body of the multiple solar cell strings 110, and power is output to the outside from the connection body of the multiple solar cell strings 110.

[0035] The interconnector 2 electrically connects adjacent solar cells 1 in series within the solar cell string 110. The interconnector 2 can be made of a conductive material such as a metal wire, a metal foil, a braided metal wire, or a twisted metal wire. The interconnector 2 is connected to the back-side connection electrode 15 and the front-side connection electrode 22 using, for example, solder, a conductive adhesive, or the like.

[0036] The connection wiring 111 and the lead-out wiring 112 can be connected at one end to the solar cell 1 at the end of the solar cell string 110, and at the other end to an interconnector 2 to which no solar cell 1 to be connected exists. The connection wiring 111 and the lead-out wiring 112 can be formed from a conductive material such as a metal wire, a metal foil, a braided metal wire, or a twisted metal wire.

[0037] The surface protective material 120 protects the solar cell 1 by covering the front side of the solar cell 1 via the sealing material 140. The surface protective material 120 can be formed from a plate-shaped material. The surface protective material 120 preferably has light-transmitting properties, scratch resistance, and weather resistance. Specific materials for the surface protective material 120 include, for example, transparent resins such as acrylic resin and polycarbonate, and glass. Furthermore, the surface of the surface protective material 120 may be textured or coated with an anti-reflective coating layer to suppress light reflection.

[0038] The back surface protective material 130 protects the solar cell 1 by covering the back side of the solar cell 1 via the sealing material 140. The back surface protective material 50 can be formed from a plate-like or sheet-like material. The back surface protective material 50 preferably has excellent water-blocking properties. Specifically, the back surface protective material 50 can be formed from a plate or film made of, for example, polyethylene terephthalate, polyethylene, fluorine-containing resin, glass, or the like, or may be formed from a laminate of such a plate or film and a metal foil such as aluminum foil.

[0039] The encapsulant 140 is filled between the front surface protective material 120 and the back surface protective material 130 to protect the solar cell 1 from moisture and other factors. Examples of suitable encapsulant 140 include translucent resins such as ethylene / vinyl acetate copolymer, ethylene / α-olefin copolymer, ethylene / vinyl acetate / triallyl isocyanurate, polyvinyl butyrate, acrylic resin, urethane resin, and silicone resin. The encapsulant 140 may be formed from a non-crosslinked resin that does not contain a crosslinking agent. When a resin containing a crosslinking agent is used as the encapsulant 140, the viscosity of the encapsulant 140 is low when the encapsulant 140 is melted to form the solar cell module 100. Therefore, the pressure applied during sealing increases the flow of the encapsulant 140, which can cause misalignment of the interconnector 2, damage the front-side photoelectric conversion layer 20, scrape off the film, and thin the film thickness. In this case, the interconnector 2 may come into contact with the intermediate transparent electrode layer 19. On the other hand, when a non-crosslinked resin is used as the sealing material 140, the viscosity of the sealing material 140 can be set higher when the sealing material 140 is melted to form the solar cell module 100, compared to when a resin containing a crosslinking agent is used. In other words, the pressure during sealing can suppress the flow of the sealing material, thereby suppressing misalignment of the solar cell 1 and the interconnector 2 and suppressing damage to the front-side photoelectric conversion layer 20. Therefore, when a non-crosslinked sealing material 140 is used, by setting the intermediate transparent electrode layer 19 back from the bonding layer 18, there is a significant effect of preventing the interconnector 2 from contacting the intermediate transparent electrode layer 19 due to the pressure during sealing.

[0040] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and various modifications and variations are possible. For example, in a solar cell according to the present invention, one or more additional layers having a passivation function, a charge selection function, etc. may be provided between the front-side photoelectric conversion layer and the intermediate transparent electrode layer and the front-side photoelectric conversion layer. The passivation layers on the front and back sides of the semiconductor substrate may be omitted. The back-side transparent electrode layer may be omitted, and a back-side connection electrode may be laminated on the entire back surface of the second semiconductor layer. Furthermore, in a solar cell module according to the present invention, the connection of solar cell strings is not limited to series, and some or all of the solar cell strings may be connected in parallel.

[0041] The present invention will be specifically described below based on examples, but the present invention is not limited to the following examples.

[0042] Solar cell prototypes were fabricated with the structures shown in Figures 1 and 2, with the intermediate transparent electrode layer recessed from the junction layer at different distances, and their output was measured. The specific recession distances from the junction layer for the intermediate transparent electrode layer in each prototype were 20 μm, 50 μm, 100 μm, 200 μm, 500 μm, 700 μm, and 1000 μm. The output of these prototypes relative to the theoretical output were 90.0%, 95.0%, 99.8%, 99.7%, 99.4%, 99.1%, and 98.5%. The results are shown in the graph in Figure 5. Thus, it was confirmed that the output of the solar cell could be improved by recessing the intermediate transparent electrode layer from the junction layer to a certain extent.

[0043] REFERENCE SIGNS LIST 1 solar cell 2 interconnector 11 semiconductor substrate 12 first passivation layer 13 first semiconductor layer 14 rear transparent electrode layer 15 rear connection electrode 16 second passivation layer 17 second semiconductor layer 18 bonding layer 19 intermediate transparent electrode layer 20 front photoelectric conversion layer 21 front transparent electrode layer 22 front connection electrode 100 solar cell module 110 solar cell string 111 connection wiring 112 lead wiring 120 surface protective material 130 rear surface protective material 140 sealing material

Claims

1. A solar cell comprising: a semiconductor substrate; a first semiconductor layer laminated on the back side of the semiconductor substrate; a back-side connection electrode disposed on the back side of the first semiconductor layer; a second semiconductor layer laminated on the front side of the semiconductor substrate; a bonding layer laminated on the front side of the second semiconductor layer; an intermediate transparent electrode layer laminated on the surface of the bonding layer; a front-side photoelectric conversion layer containing a perovskite compound laminated on the front side of the intermediate transparent electrode layer; a front-side transparent electrode layer laminated on the front side of the front-side photoelectric conversion layer; and a front-side connection electrode disposed on the surface of the front-side transparent electrode layer, wherein at least a part of the outer edge of the intermediate transparent electrode layer recedes inward in plan view from the outer edge of the bonding layer so as to bring the front-side photoelectric conversion layer into contact with the end of the bonding layer.

2. A solar cell string comprising: a plurality of solar cells according to claim 1 arranged in a row; and a plurality of interconnects connecting the back-side connection electrode of one of the adjacent two solar cells and the back-side connection electrode of the other solar cell, wherein the outer edge of the intermediate transparent electrode layer recedes inward from the outer edge of the bonding layer in a region where the interconnects intersect in plan view.

3. A solar cell module comprising: the solar cell string according to claim 2; a surface protection material covering the front side of the solar cell string; a back surface protection material covering the back side of the solar cell string; and a sealing material filled in a space around the solar cell string between the surface protection material and the back surface protection material.

4. The solar cell module according to claim 3, wherein the sealing material is formed of an uncrosslinked resin.

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