Perovskite solar cell

Abstract

To provide a perovskite solar cell capable of suppressing deterioration in performance.SOLUTION: A perovskite solar cell 100 includes: a conductive layer 2 laminated on a substrate 1; a photoelectric conversion layer 32 that is laminated on the conductive layer 2 and absorbs light energy to convert it into electric energy; a conductive sealing layer 5 that shields the photoelectric conversion layer 32; and an insulative adhesive layer 4 that is arranged between the photoelectric conversion layer 32 and the sealing layer 5 and bonds the conductive layer 2 and the sealing layer 5 so as to surround the photoelectric conversion layer 32. The adhesive layer 4 has an extension unit 41 extending to the outside of the sealing layer 5.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to perovskite solar cells. [Background technology]

[0002] Perovskite solar cells, a type of solar cell that converts solar light energy into electrical energy, have attracted attention because of their high energy conversion efficiency and light weight compared to other solar cells. However, perovskite solar cells have the problem that they are easily deteriorated by oxygen, water, etc., and various techniques have been proposed to address this problem (for example, see Patent Document 1).

[0003] Patent Document 1 discloses a perovskite solar cell that includes a support, a solar cell element provided on the support, an adhesive layer that covers the entire solar cell element, and a sealant layer that covers the entire adhesive layer and prevents water and the like from entering the solar cell element. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2023-42617 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the perovskite solar cell disclosed in Patent Document 1, the entire adhesive layer is covered with a sealant layer, and there is a risk that the end of the sealant layer may come into contact with the substrate. Therefore, for example, if the sealant layer is conductive, the sealant layer may come into contact with a conductive portion provided on the substrate through which electrons generated in the solar cell element pass, causing a short circuit, which may degrade the performance of the perovskite solar cell.

[0006] The present invention has been made in view of the above problems, and an object of the present invention is to provide a perovskite solar cell that can suppress deterioration in performance. [Means for solving the problem]

[0007] In view of the above, a characteristic configuration of a perovskite solar cell is that it comprises an electrically conductive layer laminated on a substrate, a photoelectric conversion layer laminated on the conductive layer and absorbing light energy and converting it into electrical energy, a conductive sealing layer that shields the photoelectric conversion layer, and an insulating adhesive layer that is disposed between the photoelectric conversion layer and the sealing layer and bonds the conductive layer and the sealing layer so as to surround the photoelectric conversion layer, and the adhesive layer has an extension portion that extends outward beyond the sealing layer.

[0008] According to this characteristic configuration, since the insulating adhesive layer has an extension portion that extends outward beyond the sealing layer, contact between the sealing layer and the conductive layer can be avoided to prevent the occurrence of a short circuit, thereby suppressing a decrease in the performance of the perovskite solar cell. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a perovskite solar cell according to an embodiment. [Diagram 2] FIG. 2 is a plan view of the perovskite solar cell shown in FIG. [Diagram 3] FIG. 3 is a diagram showing a schematic cross section taken along line III-III shown in FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of a perovskite solar cell according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0011] [Schematic configuration of perovskite solar cell] The schematic configuration of a perovskite solar cell 100 will be described with reference to Fig. 1. Fig. 1 is a diagram showing the schematic configuration of a perovskite solar cell 100.

[0012] As shown in Fig. 1, the perovskite solar cell 100 includes a substrate 1, a conductive layer 2, a solar cell element 3, an adhesive layer 4, and a sealing layer 5. The substrate 1, the conductive layer 2, the solar cell element 3, the adhesive layer 4, and the sealing layer 5 are laminated in this order. Hereinafter, the direction from the substrate 1 to the sealing layer 5 is referred to as the "Z1 direction" (an example of a lamination direction), the opposite direction is referred to as the "Z2 direction", and the Z1 direction and the Z2 direction are collectively referred to as the "Z direction". The orientation of the perovskite solar cell 100 during use is not particularly limited.

[0013] 〔substrate〕 The substrate 1 functions as a support for the perovskite solar cell 100. The substrate 1 is a transparent glass substrate, a semi-transparent glass substrate, a transparent resin substrate, or the like, and has insulating properties. As shown in Fig. 2, the substrate 1 has a rectangular shape when viewed along the Z2 direction (hereinafter referred to as "planar view"), and as shown in Fig. 1, a conductive layer 2 having electrical conductivity is laminated on the substrate 1.

[0014] [Conductive Layer] The conductive layer 2 is formed on one surface (surface in the Z1 direction) of the substrate 1 by CVD (chemical vapor deposition), sputtering, or the like. In this embodiment, the conductive layer 2 is formed on the entire surface of one surface of the substrate 1. The conductive layer 2 includes, for example, fluorine-doped tin oxide (FTO), tin oxide (TO), or the like as a material. The solar cell element 3 is laminated on the Z1 direction surface of the conductive layer 2 (surface farther from the substrate 1).

[0015] [Solar Cell Element] The solar cell element 3 converts light energy into electrical energy. The solar cell element 3 has an electron transport layer 31, a photoelectric conversion layer 32, and a hole transport layer 33. The electron transport layer 31, the photoelectric conversion layer 32, and the hole transport layer 33 are provided in this order along the Z1 direction.

[0016] The electron transport layer 31 receives and transports electrons from the photoelectric conversion layer 32 described below. The electron transport layer 31 contains, as a material, a metal oxide such as titanium oxide, tin oxide, zinc oxide, etc. The substrate 1, the conductive layer 2, and the electron transport layer 31 are optically transparent, and light L such as sunlight and indoor light is guided to the photoelectric conversion layer 32 without being substantially absorbed (or absorbed) by the substrate 1, the conductive layer 2, and the electron transport layer 31.

[0017] The photoelectric conversion layer 32 absorbs light energy and converts it into electrical energy. Specifically, the photoelectric conversion layer 32 absorbs light L and transfers excited electrons and holes to perform photoelectric conversion. The photoelectric conversion layer 32 includes a perovskite layer made of a perovskite compound. The photoelectric conversion layer 32 may further include a porous oxide semiconductor layer (e.g., a porous titanium layer).

[0018] The hole transport layer 33 receives and transports holes from the photoelectric conversion layer 32. The hole transport layer 33 contains, for example, an organic compound such as chlorobenzene as a material. An adhesive layer 4 is provided on the hole transport layer 33 in the Z1 direction (the surface on the side farther from the photoelectric conversion layer 32).

[0019] [Adhesive layer] The adhesive layer 4 is provided so as to face the conductive layer 2 with the solar cell element 3 interposed therebetween. In this embodiment, the adhesive layer 4 is provided so as to be spaced apart from the solar cell element 3 in the Z direction. That is, the adhesive layer 4 has a gap G between it and the solar cell element 3 in the Z direction. At the same time, the adhesive layer 4 adheres (bonds) to the conductive layer 2 so as to surround the solar cell element 3 (see FIG. 2). As a result, an internal space S for accommodating the solar cell element 3 is formed between the adhesive layer 4 and the conductive layer 2. Note that in this embodiment, the adhesive layer 4 is also spaced apart from the solar cell element 3 in a direction perpendicular to the Z direction.

[0020] The adhesive layer 4 has insulating properties. The adhesive layer 4 contains an ionomer resin or the like as a material. In this embodiment, the adhesive layer 4 is an embossed sheet-like adhesive, and has recesses 4a and protrusions 4b (see the partial enlarged views of FIGS. 1 and 2). That is, the adhesive layer 4 is an adhesive sheet having projections and recesses.

[0021] 1, a sealing layer 5 is laminated on a surface of the adhesive layer 4 in the Z1 direction (the surface farther from the solar cell element 3). That is, the adhesive layer 4 is disposed between the solar cell element 3 and the sealing layer 5. The adhesive layer 4 bonds the conductive layer 2 and the sealing layer 5.

[0022] [Sealing layer] The sealing layer 5 shields the solar cell element 3 (photoelectric conversion layer 32). More specifically, the sealing layer 5 seals the internal space S to prevent water, oxygen, and the like from entering the internal space S. In this embodiment, the internal space S is filled with nitrogen gas. Since the internal space S is filled with nitrogen gas and oxygen is prevented from entering, deterioration (oxidation) of the solar cell element 3 is prevented. Note that the internal space S may be filled with an inert gas such as a rare gas instead of nitrogen gas.

[0023] The sealing layer 5 is a sheet-like sealant, and includes a barrier layer 51 that prevents the intrusion of water, oxygen, and the like into the internal space S, and a sealing base material 52 on which the barrier layer 51 is laminated.

[0024] The barrier layer 51 is conductive. The barrier layer 51 contains, as a material, a metal oxide such as aluminum oxide or silicon oxide, a metal such as aluminum, or the like. In this embodiment, the barrier layer 51 is provided on the Z2 side surface (the surface closer to the adhesive layer 4) of the sealing substrate 52. The sealing substrate 52 is a sheet-like substrate, and contains, as a material, a PET (polyethylene terephthalate) resin, or the like.

[0025] When light L reaches the photoelectric conversion layer 32 via the substrate 1, the conductive layer 2, and the electron transport layer 31, the light L is absorbed in the photoelectric conversion layer 32, generating electrons and holes. The generated electrons move to an electrode (cathode) electrically connected to the conductive layer 2 via the electron transport layer 31. At the same time, holes generated in the photoelectric conversion layer 32 move to an electrode (anode) electrically connected to the hole transport layer 33. When a load (not shown) is connected between the two electrodes, the holes combine with the electrons that have passed through the load. As a result, electricity is generated.

[0026] [Detailed configuration of adhesive layer and sealing layer] Next, the detailed configurations of the adhesive layer 4 and the sealing layer 5 will be described with reference to Figures 2 and 3. Figure 2 is a plan view (viewed along the Z2 direction) of the perovskite solar cell 100 shown in Figure 1, and Figure 3 is a schematic diagram showing a cross section taken along line III-III shown in Figure 2.

[0027] 2, the adhesive layer 4 has larger outer dimensions in a planar view than the solar cell element 3. Specifically, the adhesive layer 4 has a rectangular shape in a planar view, and has two first adhesive ends 4x opposed to each other in the X direction and two second adhesive ends 4y opposed to each other in the Y direction.

[0028] The X direction is one of two directions perpendicular to the Z direction, and the Y direction is a direction perpendicular to the X and Z directions. Hereinafter, one of the X directions will be referred to as the "X1 direction," and the direction opposite the X1 direction will be referred to as the "X2 direction." Similarly, one of the Y directions will be referred to as the "Y1 direction," and the direction opposite the Y1 direction will be referred to as the "Y2 direction."

[0029] The sealing layer 5 has smaller outer dimensions in a plan view than the adhesive layer 4. Specifically, the sealing layer 5 has a rectangular shape in a plan view and has two first sealing ends 5x opposed to each other in the X direction and two second sealing ends 5y opposed to each other in the Y direction.

[0030] The sealing layer 5 is disposed so as to cover a part (a central region in the X direction and the Y direction) of the adhesive layer 4. More specifically, the sealing layer 5 is laminated on the adhesive layer 4 so that the first sealing end 5x is located inside the first adhesive end 4x of the adhesive layer 4 (inside the sealing layer 5) and the second sealing end 5y is located inside the second adhesive end 4y of the adhesive layer 4 (inside the sealing layer 5). That is, the adhesive layer 4 has a portion (hereinafter referred to as "extending portion 41") that extends outside the sealing layer 5 (outside the sealing layer 5) in a plan view, and a portion (hereinafter referred to as "overlapping portion 42") that overlaps with the sealing layer 5.

[0031] As described above, the adhesive layer 4 has insulating properties. For this reason, it is possible to provide a bus bar B on the Z1 direction surface of the conductive layer 2 in the Y1 direction from the end of the extension portion 41 of the adhesive layer 4 without short-circuiting with the sealed end. The bus bar B is provided to electrically connect (e.g., connect in parallel) adjacent perovskite solar cells (e.g., perovskite solar cells having the same configuration).

[0032] The overlapping portion 42 includes a first overlapping region 421, a second overlapping region 422, and a third overlapping region 423. The second overlapping region 422 is provided in an annular shape along the outer edge of the first overlapping region 421, and the third overlapping region 423 is provided in an annular shape along the outer edge of the second overlapping region 422.

[0033] The first overlapping region 421 is a part of the overlapping portion 42 facing the solar cell element 3 in the Z direction. For this reason, hereinafter, the first overlapping region 421 will be referred to as the "facing region 421." As described with reference to FIG. 1, the facing region 421 is separated from the solar cell element 3 in the Z direction.

[0034] The third overlap region 423 is a part of the overlapping portion 42 (adhesive layer 4) that is adhered to the conductive layer 2 and the sealing layer 5 by being heated and pressed (hereinafter referred to as "compression bonding") by a heater (e.g., a ribbon heater). For this reason, hereinafter, the third overlap region 423 will be referred to as the "adhesive region 423." The third overlap region 423 is compressed by a heater at a temperature of, for example, 130°C to 200°C, preferably 160°C. In this embodiment, a pressure mark P is formed in the adhesive region 423.

[0035] By bonding a portion of the conductive layer 2 (a portion facing the bonding region 423 in the Z direction) and a portion of the sealing layer 5 (a portion facing the bonding region 423 in the Z direction) in a ring shape surrounding the solar cell element 3, the intrusion of oxygen, water, etc. into the internal space S is prevented, and deterioration of the solar cell element 3 can be prevented.

[0036] Furthermore, as described above, the only portion of the adhesive layer 4 that is compressed by the heater is the adhesive region 423, and the only portion of the perovskite solar cell 100 that is compressed by the heater is the portion that faces the adhesive region 423 in the Z direction. In other words, the facing region 421 of the adhesive layer 4 that faces the solar cell element 3 in the Z direction is not compressed, and the solar cell element 3 of the perovskite solar cell 100 is not compressed.

[0037] Therefore, according to the above configuration, heat and / or pressure is not applied to the solar cell element 3 (photoelectric conversion layer 32) when the adhesive layer 4 is bonded. This makes it possible to suppress a decrease in performance of the perovskite solar cell 100. In addition, since heat is not applied to the solar cell element 3 during bonding, the adhesive layer 4 can be heated at a higher temperature (higher than a configuration in which the adhesive layer is bonded by applying heat to the solar cell element). That is, a resin or the like having a melting point at a relatively high temperature (for example, 130°C to 200°C) can be selected as the material for the adhesive layer 4. Bonding with a resin or the like having a relatively high melting point improves the adhesive performance (adhesive strength). This makes it possible to more reliably shield the solar cell element 3 (seal the internal space S), and suppress a decrease in performance of the perovskite solar cell 100.

[0038] Furthermore, according to the above configuration, since the insulating adhesive layer 4 has the extension portion 41, the sealing layer 5 (conductive barrier layer 51) and the conductive layer 2 are insulated from each other, and the occurrence of a short circuit between the sealing layer 5 and the conductive layer 2 can be suppressed. As a result, a decrease in the performance (energy conversion efficiency) of the perovskite solar cell 100 can be suppressed. Note that the resistance value of the conductive layer 2 between two points facing each other via the adhesive layer 4 in the Y direction is, for example, 1.5 MΩ (megohms). For reference, in the case of a comparative example in which the insulating adhesive layer 4 does not have the extension portion 41, the resistance value of the conductive layer 2 between two points was 0.4 MΩ to 1.0 MΩ.

[0039] [Summary of the above embodiment] In the above-described embodiment, the following configurations are envisaged.

[0040] (1) A perovskite solar cell 100 comprising: an electrically conductive layer 2 laminated on a substrate 1; a photoelectric conversion layer 32 laminated on the electrically conductive layer 2 and absorbing light energy and converting it into electrical energy; a conductive sealing layer 5 that shields the photoelectric conversion layer 32; and an insulating adhesive layer 4 disposed between the photoelectric conversion layer 32 and the sealing layer 5 and adhering the electrically conductive layer 2 and the sealing layer 5 together so as to surround the photoelectric conversion layer 32, wherein the adhesive layer 4 has an extension portion 41 that extends outward beyond the sealing layer 5.

[0041] According to this configuration, since the insulating adhesive layer 4 has the extension portion 41, the sealing layer 5 (conductive barrier layer 51) and the conductive layer 2 are insulated from each other, and it is possible to suppress the occurrence of a short circuit between the sealing layer 5 and the conductive layer 2. As a result, it is possible to suppress a decrease in the performance (energy conversion efficiency) of the perovskite solar cell 100.

[0042] Furthermore, since the adhesive layer 4 has the extending portion 41, the attachment position of the bus bar B can be easily secured.

[0043] Furthermore, since the adhesive layer 4 adheres the conductive layer 2 and the sealing layer 5 so as to surround the photoelectric conversion layer 32, the solar cell element 3 can be more reliably shielded (the internal space S can be sealed), and deterioration in the performance of the perovskite solar cell 100 can be suppressed.

[0044] For example, in a configuration in which the adhesive layer 4 does not have the extending portion 41 (a configuration in which the adhesive layer 4 does not extend outward beyond the sealing layer 5), when the sealing layer 5 is processed (cut) to a predetermined size, high-precision processing (such as a gang type) is required to avoid contact between the sealing layer 5 and the conductive layer 2. However, according to the present configuration, the adhesive layer 4 extends outward beyond the sealing layer 5, and contact between the sealing layer 5 and the conductive layer 2 can be avoided, so that high-precision processing (cutting) of the sealing layer 5 is not required, and the sealing layer 5 can be processed (cut) easily. As a result, the efficiency of the manufacturing process of the perovskite solar cell 100 is improved.

[0045] (2) In the perovskite solar cell 100 of (1), it is preferable that the adhesive layer 4 is separated from the photoelectric conversion layer 32 in the stacking direction Z1 in which the photoelectric conversion layer 32 is stacked on the conductive layer 2.

[0046] According to this configuration, since heat and / or pressure is not applied to the solar cell element 3 (photoelectric conversion layer 32) during bonding of the adhesive layer 4, deterioration in performance of the perovskite solar cell 100 can be suppressed. Furthermore, since heat is not applied to the solar cell element 3 during bonding, the adhesive layer 4 can be heated at a higher temperature (higher than a configuration in which the adhesive layer 4 is bonded by applying heat to the solar cell element 3). That is, a resin or the like having a melting point at a relatively high temperature (for example, 130°C to 200°C) can be selected as the material for the adhesive layer 4. Bonding with a resin or the like having a relatively high melting point improves the adhesive performance. Therefore, the solar cell element 3 can be more reliably shielded (the internal space S can be sealed), and deterioration in performance of the perovskite solar cell 100 can be suppressed.

[0047] (3) In the perovskite solar cell 100 of (1) or (2), it is preferable that pressure marks P are formed in the adhesive layer 4 in an adhesive region 423 that bonds the conductive layer 2 and the sealing layer 5.

[0048] According to this configuration, the solar cell element 3 can be more reliably shielded (the internal space S can be sealed), and degradation in the performance of the perovskite solar cell 100 can be suppressed.

[0049] (4) In the perovskite solar cell 100 of (1) or (2), the adhesive layer 4 is preferably an adhesive sheet having projections and recesses.

[0050] This configuration suppresses the occurrence of wrinkles in the adhesive layer 4. Also, the adhesive layer 4 is easy to handle. As a result, the efficiency of the manufacturing process for the perovskite solar cell 100 is improved.

[0051] Other embodiments Next, other embodiments of the perovskite solar cell will be described.

[0052] (a) In the above embodiment, both the first adhesive end 4x and the second adhesive end 4y extended outward from the sealing layer 5, but only one of the first adhesive end 4x and the second adhesive end 4y may extend outward from the sealing layer 5.

[0053] (b) In the above embodiment, the adhesive layer 4 is separated from the solar cell element 3, but the adhesive layer 4 may be in contact with the solar cell element 3.

[0054] (c) In the above embodiment, the pressure marks P are formed in the adhesive regions 423, but the pressure marks P do not necessarily have to be formed.

[0055] (d) In the above embodiment, the recess 4a of the adhesive layer 4 is rhombic in plan view, and the protrusion 4b is linear and extends continuously so as to be inclined with respect to the first adhesive end 4x of the adhesive layer 4, and the plurality of protrusions 4b are provided so as to intersect with each other (see FIG. 1 and FIG. 2). However, the recess 4a and the protrusion 4b are not limited to the shapes shown in FIG. 1 and FIG. 2. For example, the recess 4a may be rectangular in plan view, and the plurality of protrusions 4b may be provided at a predetermined interval, and each protrusion 4b may extend parallel to the first adhesive end 4x or the second adhesive end 4y. In addition, the plurality of recesses 4a and the plurality of protrusions 4b may be provided in a spaced apart and dispersed manner. The planar shape, cross-sectional shape, etc. of the recess 4a and the protrusion 4b are not particularly limited, and may be hemispherical, arcuate, rectangular, etc. Alternatively, the adhesive layer 4 may not have the recess 4a and the protrusion 4b. In other words, the adhesive layer 4 is not limited to an adhesive sheet having protrusions and recesses.

[0056] (e) The configurations disclosed in the above embodiments can be applied in combination with configurations disclosed in other embodiments, as long as no contradiction occurs. As for other configurations, the embodiments disclosed in this specification are merely examples in all respects. Therefore, various modifications can be made as appropriate within the scope of the present disclosure. [Industrial Applicability]

[0057] The technology disclosed herein can be used in perovskite solar cells. [Explanation of symbols]

[0058] 1: substrate, 2: conductive layer, 4: adhesive layer, 5: sealing layer, 32: photoelectric conversion layer, 41: extension, 100: perovskite solar cell, 423: adhesive region, P: pressure mark, Z1: stacking direction

Claims

1. A conductive layer laminated on the substrate; a photoelectric conversion layer that is laminated on the conductive layer and absorbs light energy and converts it into electrical energy; a conductive sealing layer that shields the photoelectric conversion layer; an insulating adhesive layer that is disposed between the photoelectric conversion layer and the sealing layer and that adheres the conductive layer and the sealing layer to surround the photoelectric conversion layer; The adhesive layer has an extension portion that extends outward beyond the sealing layer.

2. The perovskite solar cell according to claim 1 , wherein the adhesive layer is spaced apart from the photoelectric conversion layer in a stacking direction in which the photoelectric conversion layer is stacked on the conductive layer.

3. The perovskite solar cell according to claim 1 or 2, wherein pressure marks are formed in the adhesive layer in an adhesive region where the conductive layer and the sealing layer are adhered.

4. The perovskite solar cell according to claim 1 or 2, wherein the adhesive layer is an adhesive sheet having projections and recesses.

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