Perovskite solar cell

Abstract

Provided is a perovskite solar cell capable of suppressing deterioration in performance. A perovskite solar cell (100) is provided with: a conductive layer (2) that is conductive and is laminated on a substrate (1); a photoelectric conversion layer (32) that is laminated on the conductive layer (2) and that absorbs light energy and converts the light energy into electric energy; a conductive sealing layer (5) that shields the photoelectric conversion layer (32); and an insulating adhesive layer (4) that is disposed between the photoelectric conversion layer (32) and the sealing layer (5) and that adheres the conductive layer (2) and the sealing layer (5) so as to surround the photoelectric conversion layer (32), the adhesive layer (4) having an extension section (41) that extends further outward than the sealing layer (5).

Description

Technical Field

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

[0002] Perovskite solar cells, a type of solar cell that converts sunlight into electrical energy, have attracted attention because they have a higher energy conversion efficiency than other solar cells and are lightweight. However, there is a problem that perovskite solar cells are easily degraded by oxygen, water, etc., and various technologies have been proposed to address these problems (for example, see Patent Document 1).

[0003] Patent document 1 discloses a perovskite solar cell including: a support, a solar cell element disposed on the support, an adhesive layer covering the entire solar cell element, and a sealant layer covering the entire adhesive layer and used to prevent water and the like from entering the solar cell element.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2023-42617

[0005] In the perovskite solar cell disclosed in Patent Document 1, the entire adhesive layer is covered by the sealant layer, and there is a risk that the end of the sealant layer may contact the substrate. Therefore, for example, when the sealant layer has conductivity, there is a risk that the sealant layer and the conductive portion provided on the substrate through which electrons generated in the solar cell element pass may come into contact and cause a short circuit, thereby reducing the performance of the perovskite solar cell. Summary of the invention

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a perovskite solar cell capable of suppressing a decrease in performance.

[0007] In view of the above content, the characteristic structure of the perovskite solar cell is that it has: a conductive conductive layer stacked on a substrate; a photoelectric conversion layer stacked on the above conductive layer, absorbing light energy and converting the above light energy into electrical energy; a conductive sealing layer that shields the above photoelectric conversion layer; and an insulating adhesive layer, which is arranged between the above photoelectric conversion layer and the above sealing layer, and bonds the above conductive layer and the above sealing layer in a manner of surrounding the above photoelectric conversion layer, and the above adhesive layer has an extension portion extending outward from the above sealing layer.

[0008] According to such a characteristic structure, the insulating adhesive layer has an extension portion extending outward from the sealing layer, so that the contact between the sealing layer and the conductive layer can be avoided to prevent the occurrence of a short circuit. Thus, the performance of the perovskite solar cell can be suppressed from being reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1It is a diagram showing a schematic structure of a perovskite solar cell according to an embodiment.

[0010] Figure 2 yes Figure 1 A top view of a perovskite solar cell is shown.

[0011] Figure 3 is a schematic representation of the Figure 2 A diagram of a cross section taken along line III-III is shown.

[0012] Description of Reference Numerals

[0013] 1...substrate; 2...conductive layer; 4...adhesive layer; 5...sealing layer; 32...photoelectric conversion layer; 41...extension portion; 100...perovskite solar cell; 423...adhesive region; P...indentation; Z1...stacking direction. DETAILED DESCRIPTION

[0014] Hereinafter, embodiments of the 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 embodiments, and various modifications can be made without departing from the gist thereof.

[0015] 〔Schematic structure of a perovskite solar cell〕

[0016] Reference Figure 1 , a schematic structure of the perovskite solar cell 100 is described. Figure 1 It is a diagram showing a schematic structure of a perovskite solar cell 100 .

[0017] like Figure 1 As shown, 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 stacked in sequence. Hereinafter, the direction from the substrate 1 toward the sealing layer 5 is referred to as the "Z1 direction" (an example of the stacking direction), and 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". In addition, the direction in which the perovskite solar cell 100 is used is not particularly limited.

[0018] [Substrate]

[0019] 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, etc., and has insulating properties. Figure 2 As shown, when viewed along the Z2 direction (hereinafter referred to as "top view"), the substrate 1 is rectangular. Figure 1 As shown, a conductive layer 2 is stacked on a substrate 1 .

[0020] 〔Conductive layer〕

[0021] The conductive layer 2 is formed on one surface (the surface in the Z1 direction) of the substrate 1 by CVD (chemical vapor deposition), sputtering, etc. In the present 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), etc. as a material. A solar cell element 3 is stacked on the surface of the conductive layer 2 in the Z1 direction (the surface on the side away from the substrate 1).

[0022] 〔Solar cell element〕

[0023] The solar cell element 3 converts light energy into electric energy. The solar cell element 3 includes 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 sequentially provided along the Z1 direction.

[0024] The electron transport layer 31 receives electrons from the photoelectric conversion layer 32 described later and transports the electrons. The electron transport layer 31 includes metal oxides such as titanium oxide, tin oxide, and zinc oxide as materials. In addition, the substrate 1, the conductive layer 2, and the electron transport layer 31 are light-transmissive, and the light L such as sunlight and indoor light is basically not absorbed by the substrate 1, the conductive layer 2, and the electron transport layer 31 (or is understood to be not absorbed), but is guided to the photoelectric conversion layer 32.

[0025] The photoelectric conversion layer 32 absorbs light energy and converts it into electrical energy. Specifically, the photoelectric conversion layer 32 absorbs light L and moves excited electrons and holes to perform photoelectric conversion. The photoelectric conversion layer 32 includes a perovskite layer composed of a perovskite compound. Alternatively, the photoelectric conversion layer 32 also includes a porous oxide semiconductor layer (e.g., a porous titanium layer).

[0026] The hole transport layer 33 receives holes from the photoelectric conversion layer 32 and transports the holes. The hole transport layer 33 contains an organic compound such as chlorobenzene as a material. The adhesive layer 4 is provided on the Z1 direction of the hole transport layer 33 (the surface away from the photoelectric conversion layer 32).

[0027] [Adhesive layer]

[0028] The adhesive layer 4 is provided to face the conductive layer 2 across the solar cell element 3. In the present embodiment, the adhesive layer 4 is provided to be separated from the solar cell element 3 in the Z direction. That is, the adhesive layer 4 has a gap G between itself and the solar cell element 3 in the Z direction. In addition, the adhesive layer 4 is bonded (bonded) to the conductive layer 2 in a manner of surrounding the solar cell element 3 (see Figure 2). Thus, an internal space S for accommodating the solar cell element 3 is formed between the adhesive layer 4 and the conductive layer 2. In addition, in the present embodiment, the adhesive layer 4 is also separated from the solar cell element 3 in a direction perpendicular to the Z direction.

[0029] The adhesive layer 4 has insulating properties. The adhesive layer 4 contains an ionomer resin or the like as a material. In the present embodiment, the adhesive layer 4 is an embossed sheet-shaped adhesive having concave portions 4a and convex portions 4b (see Figure 1 and Figure 2 That is, the adhesive layer 4 is an adhesive sheet having projections and depressions.

[0030] like Figure 1 As shown, the sealing layer 5 is laminated on the surface of the adhesive layer 4 in the Z1 direction (the surface away from the solar cell element 3). In other words, the adhesive layer 4 is arranged 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 together.

[0031] 〔Sealing layer〕

[0032] The sealing layer 5 shields the solar cell element 3 (photoelectric conversion layer 32). Specifically, the sealing layer 5 seals the internal space S to prevent water, oxygen, etc. from entering the internal space S. In the present embodiment, the internal space S is filled with nitrogen. The internal space S is filled with nitrogen and oxygen is prevented from entering, thereby preventing the degradation (oxidation) of the solar cell element 3. Alternatively, an inert gas such as a rare gas may be filled in the internal space S instead of nitrogen.

[0033] The sealing layer 5 is a sheet-shaped sealing agent, and includes a barrier layer 51 for preventing water, oxygen, etc. from entering the internal space S, and a sealing base material 52 on which the barrier layer 51 is laminated.

[0034] The barrier layer 51 has conductivity. The barrier layer 51 includes metal oxides such as aluminum oxide and silicon oxide or metals such as aluminum as a material. In the present embodiment, the barrier layer 51 is provided on the surface of the sealing substrate 52 on the Z2 side (the surface close to the adhesive layer 4). The sealing substrate 52 is a sheet-like substrate and includes PET (polyethylene terephthalate) resin as a material.

[0035] When light L reaches the photoelectric conversion layer 32 via the substrate 1, the conductive layer 2, and the electron transport layer 31, light L is absorbed in the photoelectric conversion layer 32 to generate electrons and holes. The generated electrons move to the electrode (cathode) electrically connected to the conductive layer 2 via the electron transport layer 31. In addition, the holes generated in the photoelectric conversion layer 32 move to the electrode (anode) electrically connected to the hole transport layer 33. If a load (not shown) is connected between the two electrodes, the holes combine with the electrons coming via the load. As a result, electricity is generated.

[0036] [Detailed structure of adhesive layer and sealing layer]

[0037] Next, refer to Figure 2 and Figure 3 , the detailed structures of the adhesive layer 4 and the sealing layer 5 are described. Figure 2 yes Figure 1 The top view of the perovskite solar cell 100 shown (viewed along the Z2 direction), Figure 3 It means along Figure 2 A schematic diagram of a cross section along line III-III is shown.

[0038] like Figure 2 As shown, in a plan view, the adhesive layer 4 has a larger outer dimension than the solar cell element 3. Specifically, in a plan view, the adhesive layer 4 is rectangular and has two first adhesive ends 4x facing each other in the X direction and two second adhesive ends 4y facing each other in the Y direction.

[0039] In addition, the X direction is one of the two directions perpendicular to the Z direction, and the Y direction is a direction perpendicular to the X direction and the Z direction. Hereinafter, one direction in the X direction is referred to as the "X1 direction", and the direction opposite to the X1 direction is referred to as the "X2 direction". Similarly, one direction in the Y direction is referred to as the "Y1 direction", and the direction opposite to the Y1 direction is referred to as the "Y2 direction".

[0040] In a plan view, the sealing layer 5 has a smaller outer dimension than the adhesive layer 4. Specifically, in a plan view, the sealing layer 5 is rectangular and has two first sealing ends 5x facing each other in the X direction and two second sealing ends 5y facing each other in the Y direction.

[0041] The sealing layer 5 is configured to cover a part (central region in the X direction and the Y direction) of the adhesive layer 4. Specifically, the sealing layer 5 is laminated on the adhesive layer 4 in such a manner 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, in a plan view, the adhesive layer 4 has a portion extending outside the sealing layer 5 (outside the sealing layer 5) (hereinafter referred to as an "extended portion 41") and a portion overlapping the sealing layer 5 (hereinafter referred to as an "overlapping portion 42").

[0042] As described above, the adhesive layer 4 has insulating properties. Therefore, the bus bar B can be provided on the surface of the conductive layer 2 facing the Z1 direction, which is closer to the Y1 direction than 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 (for example, connect in parallel) to an adjacent perovskite solar cell (for example, a perovskite solar cell of the same structure).

[0043] 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 a ring shape along the outer edge of the first overlapping region 421 , and the third overlapping region 423 is provided in a ring shape along the outer edge of the second overlapping region 422 .

[0044] The first overlapping region 421 is a portion of the overlapping portion 42 that faces the solar cell element 3 in the Z direction. Therefore, the first overlapping region 421 is hereinafter referred to as a "facing region 421". Figure 1 As described above, the facing region 421 is separated from the solar cell element 3 in the Z direction.

[0045] The third overlapping region 423 is a part of the overlapping portion 42 (adhesive layer 4) that is bonded to the conductive layer 2 and the sealing layer 5 by heating and pressing (hereinafter referred to as "pressing") using a heater (for example, a tape heater). Therefore, the third overlapping region 423 is hereinafter referred to as "adhesive region 423". The third overlapping region 423 is press-bonded by a heater at a temperature of, for example, 130°C to 200°C, preferably 160°C. In the present embodiment, an indentation P is formed in the adhesive region 423.

[0046] The bonding area 423 bonds a portion of the conductive layer 2 (the portion facing the bonding area 423 in the Z direction) and a portion of the sealing layer 5 (the portion facing the bonding area 423 in the Z direction) in a ring shape so as to surround the solar cell element 3, thereby preventing oxygen, water, etc. from entering the internal space S, thereby preventing the degradation of the solar cell element 3.

[0047] Furthermore, as described above, the portion of the adhesive layer 4 that is pressed by the heater is only the adhesive region 423, and the portion of the perovskite solar cell 100 that is pressed by the heater is only the portion that faces the adhesive region 423 in the Z direction. In other words, the opposing region 421 of the adhesive layer 4 that faces the solar cell element 3 in the Z direction is not pressed, and the solar cell element 3 of the perovskite solar cell 100 is not pressed.

[0048] Therefore, according to the above structure, when the adhesive layer 4 is bonded, heat and / or pressure is not applied to the solar cell element 3 (photoelectric conversion layer 32). Therefore, it is possible to suppress the reduction in the 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 (a temperature higher than the structure in which the solar cell element is heated to bond the adhesive layer). 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 of the adhesive layer 4. Bonding by a resin or the like having a relatively high melting point improves the bonding performance (bonding strength). Therefore, it is possible to more effectively shield the solar cell element 3 (seal the internal space S), and suppress the reduction in the performance of the perovskite solar cell 100.

[0049] In addition, according to the above structure, the insulating adhesive layer 4 has an extension portion 41, thereby insulating the sealing layer 5 (conductive barrier layer 51) from the conductive layer 2, and the short circuit between the sealing layer 5 and the conductive layer 2 can be suppressed. As a result, the reduction in the performance (energy conversion efficiency) of the perovskite solar cell 100 can be suppressed. In addition, in the Y direction, the resistance value of the conductive layer 2 between two points facing each other across the adhesive layer 4 is, for example, 1.5MΩ (megaohms). For reference, in the case of a comparative example in which the insulating adhesive layer 4 does not have an extension portion 41, the resistance value of the conductive layer 2 between the two points is 0.4MΩ to 1.0MΩ.

[0050] [Overview of the above-mentioned embodiment]

[0051] In the above-mentioned embodiment, the following structure is conceivable.

[0052] (1) A perovskite solar cell 100, comprising: a conductive conductive layer 2 stacked on a substrate 1; a photoelectric conversion layer 32 stacked on the conductive layer 2 and absorbing light energy and converting the light energy into electrical energy; a conductive sealing layer 5 shielding the photoelectric conversion layer 32; and an insulating adhesive layer 4 disposed between the photoelectric conversion layer 32 and the sealing layer 5 and bonding the conductive layer 2 and the sealing layer 5 in a manner surrounding the photoelectric conversion layer 32, the adhesive layer 4 having an extension portion 41 extending outward from the sealing layer 5.

[0053] According to this structure, the insulating adhesive layer 4 has an extension portion 41, thereby insulating the sealing layer 5 (conductive barrier layer 51) from the conductive layer 2, and can suppress the occurrence of a short circuit between the sealing layer 5 and the conductive layer 2. As a result, the reduction in the performance (energy conversion efficiency) of the perovskite solar cell 100 can be suppressed.

[0054] Furthermore, since the adhesive layer 4 has the extending portion 41 , the mounting position of the bus bar B can also be easily secured.

[0055] Furthermore, since the adhesive layer 4 bonds 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 is sealed), and degradation of the performance of the perovskite solar cell 100 can be suppressed.

[0056] For example, in a structure in which the adhesive layer 4 does not have an extension portion 41 (a structure in which the adhesive layer 4 does not extend outward from the sealing layer 5), when the sealing layer 5 is processed (cut) to a predetermined size, high-precision processing (composite type, etc.) is required to avoid contact between the sealing layer 5 and the conductive layer 2. However, according to this structure, the adhesive layer 4 extends outward from the sealing layer 5, and contact between the sealing layer 5 and the conductive layer 2 can be avoided. Therefore, high-precision processing (cutting) of the sealing layer 5 is not required, and the sealing layer 5 can be simply processed (cut). As a result, the efficiency of the manufacturing operation of the perovskite solar cell 100 is improved.

[0057] (2) In the perovskite solar cell 100 of (1), it is preferred 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 .

[0058] According to this structure, when the adhesive layer 4 is bonded, no heat and / or pressure is applied to the solar cell element 3 (photoelectric conversion layer 32), so the performance degradation of the perovskite solar cell 100 can be suppressed. In addition, the solar cell element 3 is not heated during bonding, so the adhesive layer 4 can be heated at a higher temperature (a temperature higher than the structure in which the solar cell element 3 is heated to bond the adhesive layer 4). That is, a resin or the like having a relatively high temperature (for example, 130°C to 200°C) as a melting point can be selected as the material of the adhesive layer 4. Bonding by bonding with a relatively high melting point resin or the like improves the bonding performance. Therefore, the solar cell element 3 can be shielded more effectively (the internal space S is sealed), and the performance degradation of the perovskite solar cell 100 can be suppressed.

[0059] (3) In the perovskite solar cell 100 of (1) or (2), it is preferred that an indentation P is formed in a bonding region 423 of the bonding layer 4 where the conductive layer 2 and the sealing layer 5 are bonded to each other.

[0060] According to this structure, the solar cell element 3 can be shielded more reliably (the internal space S can be sealed), and the reduction in the performance of the perovskite solar cell 100 can be suppressed.

[0061] (4) In the perovskite solar cell 100 of (1) or (2), the adhesive layer 4 is preferably an adhesive sheet having projections and depressions.

[0062] According to this structure, the generation of wrinkles in the adhesive layer 4 is suppressed. In addition, the handling of the adhesive layer 4 becomes easy. As a result, the efficiency of the manufacturing process of the perovskite solar cell 100 is improved.

[0063] [Other implementation methods]

[0064] Next, other embodiments of the perovskite solar cell will be described.

[0065] (a) In the above embodiment, both the first bonding end 4 x and the second bonding end 4 y extend outward from the sealant layer 5 . However, only one of the first bonding end 4 x and the second bonding end 4 y may extend outward from the sealant layer 5 .

[0066] (b) In the above-described embodiment, a structure in which the adhesive layer 4 is separated from the solar cell element 3 is described. However, the adhesive layer 4 may be in contact with the solar cell element 3 .

[0067] (c) In the above-described embodiment, the indentation P is formed in the adhesion region 423 , but the indentation P may not be formed.

[0068] (d) In the above-mentioned embodiment, the concave portion 4a of the adhesive layer 4 is rhombus-shaped when viewed from above, and is in the form of a line extending continuously in such a manner that the convex portion 4b is inclined relative to the first adhesive end 4x of the adhesive layer 4, and a plurality of convex portions 4b are arranged to intersect each other (see Figure 1 and Figure 2 ). However, the concave portion 4a and the convex portion 4b are not limited to Figure 1 and Figure 2 The shape as shown. For example, it can also be that, when viewed from above, the recess 4a is rectangular, and a plurality of protrusions 4b are arranged at predetermined intervals, and each protrusion 4b extends parallel to the first bonding end 4x or the second bonding end 4y. In addition, it can also be that a plurality of recesses 4a and a plurality of protrusions 4b are separated and dispersed. The plane shape, cross-sectional shape, etc. of the recess 4a and the protrusion 4b are not particularly limited, and can also be a hemispherical shape, an arc shape, a rectangular shape, etc. Alternatively, the adhesive layer 4 may not have the recess 4a and the protrusion 4b. That is, the adhesive layer 4 is not limited to an adhesive sheet with recesses and protrusions.

[0069] (e) In addition, the structures disclosed in the above-mentioned embodiments can also be combined with the structures disclosed in other embodiments and applied as long as no contradiction occurs. With regard to other structures, the embodiments disclosed in this specification are only simple examples in all aspects. Therefore, various changes can be appropriately made within the scope of the main purpose of the present disclosure.

[0070] Industrial Applicability

[0071] The technology disclosed herein can be utilized in perovskite solar cells.

Claims

1. A perovskite solar cell, characterized in that: have: An electrically conductive layer laminated on the substrate; a photoelectric conversion layer stacked on the conductive layer and absorbing light energy and converting the light energy into electrical energy; A conductive sealing layer, which shields the photoelectric conversion layer; as well as an insulating adhesive layer, which 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; The adhesive layer has an extending portion extending outward from the sealing layer.

2. The perovskite solar cell according to claim 1, characterized in that The adhesive layer is separated 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, characterized in that: An indentation is formed in the adhesive layer at an adhesive region where the conductive layer and the sealing layer are bonded to each other.

4. The perovskite solar cell according to claim 1 or 2, characterized in that: The adhesive layer is an adhesive sheet having projections and depressions.

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