Solar cells and stacked solar cells

Abstract

The present embodiment relates to a solar cell and a stacked solar cell. [Solution] A solar cell includes a first conductive layer, a first carrier transport layer, a perovskite absorption layer, and a second conductive layer, which are sequentially stacked along a first direction, the perovskite absorption layer includes an adhesive substrate and a plurality of single crystal perovskite particles arranged on the adhesive substrate, the adhesive substrate includes a first surface and a second surface facing each other in the first direction, at least a portion of the single crystal perovskite particles have a first convex surface and a second convex surface, the first convex surface protruding relative to the first surface, and the second convex surface protruding relative to the second surface. The present embodiment is advantageous in at least improving the stability and photoelectric conversion capacity of the solar cell.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application is filed based on and claims priority from a Chinese patent application having application number 2022116189516 and filing date December 13, 2022, the entire disclosure of which is incorporated herein by reference.

[0002] FIELD OF THE INVENTION The present embodiment relates to the field of solar cells, and in particular to solar cells and stacked solar cells. [Background technology]

[0003] Fossil energy is characterized by air pollution and limited reserves, but solar energy has the advantages of being clean, pollution-free, and abundant in resources, etc. For this reason, solar energy is gradually replacing fossil energy as the core clean energy, and because solar cells have good photoelectric conversion efficiency, they have become the most important part of clean energy utilization.

[0004] One of the key factors affecting the proportion of solar energy in energy utilization is the photoelectric conversion efficiency of solar cells. To improve the photoelectric conversion efficiency of solar cells, optimizing the structural design and material composition of the solar cell is the basic solution. Perovskite solar cells have a long service life and relatively stable photoelectric conversion efficiency, so they have good prospects for development.

[0005] However, current perovskite solar cells suffer from limited photoelectric conversion capacity and poor stability. Summary of the Invention [Problem to be solved by the invention]

[0006] The solar cells and stacked solar cells provided in the examples of the present application are at least advantageous in realizing the production of large-area perovskite cells with good photoelectric conversion efficiency and stability, and in improving the photoelectric conversion capacity of perovskite solar cells. [Means for solving the problem]

[0007] In an embodiment of the present application, a solar cell is provided, the solar cell comprising a first conductive layer, a first carrier transport layer, a perovskite absorber layer, and a second conductive layer sequentially stacked along a first direction, the perovskite absorber layer comprising an adhesive substrate and a plurality of single-crystal perovskite particles arranged on the adhesive substrate, the adhesive substrate having a first surface and a second surface facing each other in the first direction, at least some of the single-crystal perovskite particles having a first convex surface and a second convex surface, the first convex surface protruding relative to the first surface, and the second convex surface protruding relative to the second surface.

[0008] Furthermore, for any of the single-crystal perovskite particles, the distance between the current single-crystal perovskite particle and an adjacent single-crystal perovskite particle is equal to or less than the maximum distance between any two points on the surface of the current single-crystal perovskite particle.

[0009] The maximum distance between any two points on the surface of the single-crystal perovskite particle is 5 μm to 100 μm.

[0010] Furthermore, the area of ​​the orthogonal projection of the perovskite absorption layer on the first conductive layer is defined as a first area, the area of ​​the orthogonal projection of the plurality of single-crystal perovskite particles on the first conductive layer is defined as a second area, and the ratio of the second area to the first area is 0.3 to 0.9.

[0011] Furthermore, in the first direction, the distance between any one point on the first convex surface and the first surface and / or the distance between any one point on the second convex surface and the second surface is not more than half the maximum length of the single-crystal perovskite particle in the first direction.

[0012] Additionally, the thickness of the adhesive substrate in the first direction is 100 nm or more.

[0013] The adhesive substrate also includes a light-trapping surface facing the first carrier transport layer and / or the second conductive layer.

[0014] The light trapping surface also includes a first light trapping structure, the first light trapping structure extending out of the adhesive substrate in the first direction.

[0015] The light trapping surface also includes a second light trapping structure, which is recessed in the first direction toward the interior of the adhesive substrate.

[0016] The first carrier transport layer is an electron transport layer or a hole transport layer.

[0017] The thickness of the first carrier transport layer in the first direction is in the range of 1 nm to 1 μm.

[0018] The solar cell further includes a second carrier transport layer located between the perovskite absorber layer and the second conductive layer and in contact with the perovskite absorber layer and the second conductive layer, respectively.

[0019] The thickness of the second carrier transport layer in the first direction is in the range of 1 nm to 1 μm.

[0020] Furthermore, when the first carrier transport layer is a hole transport layer, the second carrier transport layer is an electron transport layer, and when the first carrier transport layer is an electron transport layer, the second carrier transport layer is a hole transport layer.

[0021] Correspondingly, the present embodiment further provides a stacked solar cell, which includes a top cell, an adhesive layer, and a bottom cell stacked in order, wherein the top cell is the above-mentioned solar cell.

[0022] The bottom cell also includes a crystalline silicon solar cell, a CIGS thin film solar cell, a cadmium telluride thin film solar cell, a III-V thin film solar cell, or a narrow bandgap perovskite thin film solar cell.

[0023] The adhesive layer also includes a mechanical bonding layer made of a conductive adhesive. [Effects of the Invention]

[0024] The technical solutions provided in the embodiments of the present application have at least the following advantages:

[0025] In the solar cell fabrication process provided in the present invention, an adhesive substrate and a plurality of single-crystalline perovskite particles arranged on the adhesive substrate are used to form the perovskite absorber layer of the solar cell. Constructing the perovskite absorber layer using single-crystalline perovskite particles ensures the stability of the perovskite absorber layer. Arranging the single-crystalline perovskite particles on the adhesive substrate avoids damage to the single-crystalline perovskite during the cutting process and ensures the efficiency of the solar cell. Constructing the perovskite absorber layer using a single-crystalline particle arrangement contributes to the production of large-area single-crystalline perovskite solar cells. Among the multiple single-crystal perovskite particles arranged in the adhesive substrate, at least some of the single-crystal perovskite particles each have a first convex surface protruding from a first surface of the adhesive substrate and a second convex surface protruding from a second surface of the adhesive substrate. By constructing a perovskite absorption layer using the single-crystal perovskite particles exposed on both opposing surfaces of the adhesive substrate, the perovskite absorption layer itself is given a textured structure, which gives it better light absorption ability and improves the ability to transport photogenerated carriers from the perovskite absorption layer to the conductive layer or carrier transport layer, thereby increasing the photoelectric conversion efficiency and capacity of the solar cell. [Brief explanation of the drawings]

[0026] One or more embodiments are illustratively illustrated in the accompanying drawing figures, but these illustrative illustrations are not intended to be limiting of the embodiments, and unless otherwise specified, the accompanying drawing figures are not drawn to scale. [Figure 1] FIG. 1 is a diagram showing the structure of a solar cell according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of a solar cell according to an embodiment of the present application. [Figure 3] FIG. 3 is a top view of a perovskite absorber layer of a solar cell according to one embodiment of the present application. [Figure 4] FIG. 4 is a cross-sectional view of a perovskite absorber layer according to one embodiment of the present application. [Figure 5] FIG. 5 is a cross-sectional view of another solar cell according to an embodiment of the present application. [Figure 6] FIG. 6 is a cross-sectional view of another solar cell according to an embodiment of the present application. [Figure 7] FIG. 7 is a cross-sectional view of another solar cell according to an embodiment of the present application. [Figure 8] FIG. 8 is a cross-sectional view of another solar cell according to an embodiment of the present application. [Figure 9] FIG. 9 is a cross-sectional view of another solar cell according to an embodiment of the present application. [Figure 10] FIG. 10 is a diagram showing the structure of another solar cell according to an embodiment of the present application. [Figure 11] FIG. 11 is a diagram showing the structure of a stacked solar cell according to one embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0027] As can be seen from the background art, perovskite solar cells have good prospects due to their advantages of long service life and photoelectric conversion efficiency, but current perovskite solar cells have limited photoelectric conversion capacity and poor stability.

[0028] In one embodiment of the present application, a solar cell is provided, in which a perovskite absorber layer of the solar cell is formed using an adhesive substrate and a plurality of single-crystalline perovskite particles arranged on the adhesive substrate during the manufacturing process of the solar cell. By constructing the perovskite absorber layer using single-crystalline perovskite particles, the stability of the perovskite absorber layer is ensured. By using a form in which the single-crystalline perovskite particles are arranged on the adhesive substrate, damage to the single-crystalline perovskite during the cutting process is avoided and the efficiency of the solar cell is ensured. The construction of the perovskite absorber layer using a single-crystalline particle arrangement contributes to the manufacturing of large-area single-crystalline perovskite solar cells. Among the multiple single-crystal perovskite particles arranged in the adhesive substrate, at least some of the single-crystal perovskite particles each have a first convex surface protruding from a first surface of the adhesive substrate and a second convex surface protruding from a second surface of the adhesive substrate. By constructing a perovskite absorption layer using the single-crystal perovskite particles exposed on both opposing surfaces of the adhesive substrate, the perovskite absorption layer itself is given a textured structure, which gives it better light absorption ability and improves the ability to transport photogenerated carriers from the perovskite absorption layer to the conductive layer or carrier transport layer, thereby increasing the photoelectric conversion efficiency and capacity of the solar cell.

[0029] Hereinafter, each embodiment of the present application will be described in detail with reference to the accompanying drawings. However, as will be understood by those skilled in the art, although many technical details are proposed in each embodiment of the present application to help readers better understand the present application, the technical solution claimed for protection by the present application can be realized without these technical details and various changes and modifications based on the following embodiments.

[0030] As shown in FIGS. 1 to 3, one embodiment of the present application provides a solar cell, where FIG. 1 is a diagram showing an overall structure of the solar cell, FIG. 2 is a diagram showing a cross-sectional structure of the solar cell, and FIG. 3 is a top view of a perovskite absorber layer 103, where the X direction is a first direction.

[0031] The solar cell comprises a first conductive layer 101, a first carrier transport layer 102, a perovskite absorption layer 103 and a second conductive layer 104 sequentially stacked along a first direction, the perovskite absorption layer 103 comprising an adhesive substrate 1031 and a plurality of single-crystal perovskite particles 1032 arranged on the adhesive substrate 1031, the adhesive substrate 1031 having opposing first and second surfaces in the first direction, at least some of the single-crystal perovskite particles 1032 having a first convex surface and a second convex surface, the first convex surface protruding relative to the first surface and the second convex surface protruding relative to the second surface.

[0032] The adhesive substrate 1031 is used to accommodate and fix the single-crystal perovskite particles 1032 arranged in the adhesive substrate 1031. Therefore, the adhesive substrate 1031 can be made of a transparent curable adhesive or colloid. For example, the adhesive substrate 1031 can be made of a UV-curable adhesive such as an acrylic adhesive or a resin adhesive, or other types of curable transparent adhesive. Here, transparency means having good light transmittance for visible light, for example, a transmittance of 80% or more for light of 400 nm or more, or a transmittance of 75% or more for light of 450 nm or more.

[0033] The solar cell absorbs light irradiated onto the solar cell through the perovskite absorption layer 103, then generates photo-generated carriers through the single-crystal perovskite particles 1032, collects different photo-generated carriers through the first carrier transport layer 102 and the second conductive layer 104, respectively, and finally transports the electrical energy generated by the solar cell to an external module via the first conductive layer 101 and the second conductive layer 104.

[0034] During operation of a solar cell, the photoelectric conversion efficiency of the cell is mainly affected by the generation ability of photo-generated carriers and the collection and utilization ability of the photo-generated carriers. In the process of constructing the perovskite absorber layer 103, the perovskite absorber layer 103 is constructed using an adhesive substrate 1031 and a plurality of single-crystalline perovskite particles 1032 arranged on the adhesive substrate 1031. This ensures the integrity of the single-crystalline perovskite particles 1032, avoids damage to the single-crystalline perovskite material during the construction of the perovskite absorber layer 103, and ensures the generation ability of the photo-generated carriers of the perovskite absorber layer 103.

[0035] In addition, constructing the perovskite absorber layer 103 with single-crystal perovskite particles 1032 reduces the decomposition rate of the perovskite absorber layer 103 during operation of the cell, ensuring the stability of the perovskite absorber layer 103 and the solar cell, and the single-crystal perovskite particles 1032 have a longer carrier lifetime, higher carrier mobility, and longer carrier diffusion length, thereby providing the solar cell with higher photoelectric conversion efficiency and service life.

[0036] At the same time, constructing the perovskite absorber layer 103 by arranging single-crystal perovskite particles 1032 on an adhesive substrate 1031 helps to easily and efficiently manufacture large-area perovskite absorber layers 103, breaks through the constraints imposed by the production efficiency of single-crystal perovskite raw materials on the perovskite absorber layer 103 and the area of ​​perovskite solar cells, greatly improves the production efficiency of stable large-area perovskite solar cells, and enhances the prospects for the application of single-crystal perovskite solar cells.

[0037] 2, in a first direction, the adhesive substrate 1031 has a first surface and a second surface opposite to each other, and at least some of the single-crystalline perovskite particles 1032 have a first convex surface and a second convex surface, with the first convex surface protruding from the first surface and the second convex surface protruding from the second surface. During the process of constructing the perovskite absorber layer 103, it is ensured that at least some of the single-crystalline perovskite particles 1032 have a first convex surface and a second convex surface protruding from the surfaces on the two opposite surfaces of the adhesive substrate 1031, respectively, i.e., at least some of the single-crystalline perovskite particles 1032 penetrate the adhesive substrate 1031 to contact the first carrier transport layer 102 and the second conductive layer 104. Because at least some of the single-crystalline perovskite particles 1032 have a first convex surface and a second convex surface, the two opposing surfaces of the perovskite absorber layer 103 are textured, improving the light absorption ability of the perovskite absorber layer 103. At the same time, because at least some of the single-crystalline perovskite particles 1032 penetrate the adhesive substrate 1031 and contact the first carrier transport layer 102 and the second conductive layer 104, after photo-generated carriers are generated, it is much easier for the photo-generated carriers to move to the first carrier transport layer 102 and the second conductive layer 104, thereby improving the photo-generated carrier transport ability of the perovskite absorber layer 103. Consequently, the photoelectric conversion efficiency of the perovskite absorber layer 103 is improved through both light absorption ability and carrier transport ability.

[0038] The shape of the single-crystal perovskite particles 1032 may be a sphere, a spherical approximation, a regular polyhedron including a cube, or an irregular polyhedron, and the size and shape of each single-crystal perovskite particle 1032 contained in the perovskite absorption layer 103 may or may not be the same. This is not a limitation in the present embodiment. For ease of understanding and explanation, the present embodiment will be described using an example in which the perovskite particles are spherical. During actual use, the shape of the single-crystal perovskite particles 1032 may be adjusted as needed. This is not a limitation in the present embodiment.

[0039] Furthermore, the single-crystal perovskite particles 1032 contained in the perovskite absorber layer 103 may all have a first convex surface and a second convex surface, or some of the particles may have a first convex surface and a second convex surface, and the remaining particles may have only a first convex surface, only a second convex surface, or no first convex surface or no second convex surface, but this is not a limitation in the examples of the present application.

[0040] Furthermore, the single-crystal perovskite particles 1032 in the perovskite absorption layer 103 may be arranged in a regular array at regular intervals in the adhesive substrate 1031, for example, in a rectangular, near-rectangular, circular, or elliptical shape, which can improve the uniformity of the light absorption and carrier output of the perovskite absorption layer 103. Alternatively, they may be freely arranged at any interval and in any order on the adhesive substrate 1031, although this is not a limitation in the embodiments of the present application.

[0041] In some embodiments, for any single-crystalline perovskite grain 1032, the spacing between the current single-crystalline perovskite grain and an adjacent single-crystalline perovskite grain 1032 is less than or equal to the maximum spacing between any two points on the surface of the current single-crystalline perovskite grain.

[0042] 3, the two largest circles in the figure are circles formed through the centers of two horizontally adjacent single-crystalline perovskite particles 1032. The maximum distance between any two points on the surface of the current single-crystalline perovskite particle is d, and the distance between the current single-crystalline perovskite particle and the adjacent single-crystalline perovskite particle 1032 is D, where D can represent the minimum distance between any point on the surface of the current single-crystalline perovskite particle and any point on the surface of the adjacent single-crystalline perovskite particle 1032. If the distance between two adjacent single-crystalline perovskite particles 1032 is too large, the perovskite absorption layer 103 will have a very poor absorption ability for light irradiated into the region between the two adjacent single-crystalline perovskite particles 1032. This will reduce the light absorption ability of the perovskite absorption layer 103 and affect the photoelectric conversion ability of the perovskite absorption layer 103.

[0043] On the other hand, since the light absorption ability of the single-crystalline perovskite particles 1032 gradually decreases as the distance between them and the light increases, it is necessary to limit the distance D between two adjacent single-crystalline perovskite particles 1032 in the perovskite absorption layer 103. The distance D between the current single-crystalline perovskite particle and the adjacent single-crystalline perovskite particle 1032 is set to a range smaller than the size of the current single-crystalline perovskite particle, i.e., a range smaller than the maximum distance d between any two points on the surface of the current single-crystalline perovskite particle. For example, D may be set to 0.1d, 0.2d, 0.35d, 0.45d, 0.5d, 0.75d, or 0.9d. By setting the distance between the current single-crystal perovskite particle and the adjacent single-crystal perovskite particle 1032 to a range equal to or smaller than the size of the current single-crystal perovskite particle, the perovskite absorption layer 103 has good light absorption ability, and the problem of a decrease in the photoelectric conversion efficiency of the solar cell due to a decrease in light absorption ability can be avoided.

[0044] In some embodiments, the distance in the first direction between any point on the first convex surface and the first surface and / or the distance in the second convex surface between any point on the second convex surface and the second surface is less than or equal to half the maximum length in the first direction of the single-crystal perovskite grain 1032.

[0045] As shown in Figures 2 and 4, Figure 4 is a cross-sectional view of a perovskite absorber layer 103 formed along the vertical direction through the spherical centers of three identically sized single-crystal perovskite particles 1032. In the perovskite absorber layer 103, in a first direction, the maximum distance between any one point on a first convex surface of a single-crystal perovskite particle 1032 and the first surface of the adhesive substrate 1031 is the distance a between the first surface and point A on the first convex surface that is farthest from the first surface; similarly, the maximum distance between any one point on a second convex surface of a single-crystal perovskite particle 1032 and the second surface of the adhesive substrate 1031 is the distance b between the first surface and point B on the second convex surface that is farthest from the second surface; and the maximum length of the single-crystal perovskite particle 1032 is L.

[0046] In the process of constructing the perovskite absorption layer 103, the role of the adhesive substrate 1031 is to fix the single-crystalline perovskite particles 1032, and to ensure the fixation effect, the adhesive substrate 1031 has a certain thickness. Meanwhile, in the process of generating carriers in the single-crystalline perovskite particles 1032, different carriers collect and move at both ends of the single-crystalline perovskite particles 1032, respectively. If the distance a between point A on the first convex surface of the single-crystalline perovskite particle 1032 and the first surface is equal to or greater than 1 / 2 of L, and / or the distance b between point B on the second convex surface of the single-crystalline perovskite particle 1032 and the second surface is equal to or greater than 1 / 2 of L, the carriers collected in the first carrier transport layer 102 or the second conductive layer 104 may recombine with anisotropic carriers, resulting in a decrease in the photoelectric conversion efficiency of the perovskite absorption layer 103.

[0047] Therefore, in the process of constructing the perovskite absorber layer 103, for a single-crystal perovskite particle 1032 including a first convex surface and a second convex surface, the distance between any one point on the first convex surface of the single-crystal perovskite particle 1032 and the first surface and / or the distance between any one point on the second convex surface of the single-crystal perovskite particle 1032 and the second surface in the first direction is ensured to be equal to or less than half the maximum length of the single-crystal perovskite particle 1032 in the first direction. For example, the distance a and / or the distance b is set to 0.1L, 0.15L, 0.2L, 0.25L, 0.35L, 0.45L, or 0.49L. By limiting the distance between any one point on the first convex surface of the single-crystal perovskite particle 1032 and the first surface and / or the distance between any one point on the second convex surface of the single-crystal perovskite particle 1032 and the second surface, the probability of anisotropic carrier recombination is reduced as much as possible, thereby ensuring the photoelectric conversion efficiency of the solar cell.

[0048] In some embodiments, the maximum distance between any two points on the surface of the single-crystal perovskite particles 1032 is between 5 μm and 100 μm.

[0049] If the size of the selected single-crystal perovskite particles 1032 in the process of constructing the perovskite absorption layer 103 is too large, i.e., the maximum distance d between any two points on the particle surface is too large, then after the perovskite absorption layer is constructed using the single-crystal perovskite particles 1032, the distance required for the carriers to travel to the first carrier transport layer 102 or the second conductive layer 104 after absorbing light energy is too long, making it difficult for the carriers to complete their migration and resulting in a decrease in the photoelectric conversion efficiency of the solar cell. If the size of the single-crystal perovskite particles 1032 is too small, i.e., the maximum distance d between any two points on the particle surface is too small, then the pitch between different carriers is small during the carrier migration process, making carrier recombination more likely to occur, resulting in a decrease in the photoelectric conversion efficiency of the solar cell. Furthermore, if the size of the single-crystalline perovskite particles 1032 is too small, the thickness of the perovskite absorption layer 103 will also be small, which will significantly increase the probability of the single-crystalline perovskite particles 1032 being decomposed due to the potential difference between the two sides, resulting in a decrease in the stability of the solar cell.

[0050] Therefore, in the process of constructing the perovskite absorber layer 103, single-crystal perovskite particles 1032 with a maximum distance between any two points on the particle surface of 5 μm to 100 μm are selected for construction, for example, single-crystal perovskite particles 1032 with a maximum distance between any two points on the particle surface of 5 μm, 7.5 μm, 10 μm, 15 μm, 25 μm, 60 μm, 80 μm, 85 μm, or 95 μm are selected to construct the perovskite absorber layer 103. This ensures that carriers in the perovskite absorber layer 103 can easily move, while reducing the probability of recombination between different carriers and the probability of decomposition of the single-crystal perovskite particles 1032, thereby ensuring the photoelectric conversion efficiency and stability of the solar cell.

[0051] In some embodiments, the area of ​​the orthogonal projection of the perovskite absorber layer 103 on the first conductive layer 101 is defined as the first area, the area of ​​the orthogonal projection of the plurality of single-crystal perovskite particles 1032 on the first conductive layer 101 is defined as the second area, and the ratio of the second area to the first area is 0.3 to 0.9.

[0052] In the process of constructing the perovskite absorber layer 103, the light absorption area of ​​the perovskite absorber layer 103 when it performs photoelectric conversion can be regarded as the sum of the orthogonal projection areas of all the single-crystal perovskite particles 1032 on the first conductive layer 101, i.e., the second area. Meanwhile, the area that the perovskite absorber layer 103 receives light can be regarded as the orthogonal projection area of ​​the perovskite absorber layer 103 on the first conductive layer 101, i.e., the first area. If the ratio of the second area to the first area is too small, the absorption utilization rate of the perovskite absorber layer 103 for light irradiated thereon will be low, resulting in a weak photoelectric conversion ability of the solar cell and making it difficult to perform photoelectric conversion effectively. Due to limitations in the photoelectric conversion capacity of the single-crystal perovskite particles 1032 themselves, there is an upper limit to the absorption utilization rate of the perovskite absorption layer 103 for light irradiated onto the perovskite absorption layer 103. If the ratio of the second area to the first area is too large, the perovskite absorption layer 103 will contain single-crystal perovskite particles 1032 whose photoelectric conversion capacity is not fully utilized, resulting in poor cost performance between the manufacturing cost of the solar cell and its photoelectric conversion capacity.

[0053] Therefore, in the process of constructing the perovskite absorber layer 103, it is necessary to limit the ratio between the area of ​​the orthogonal projection of each single-crystal perovskite particle 1032 in the perovskite absorber layer 103 on the first conductive layer 101 and the area of ​​the orthogonal projection of the perovskite absorber layer 103 on the first conductive layer 101. The ratio of the second area to the first area is set within a range of 0.3 to 0.9, for example, 0.3, 0.35, 0.45, 0.5, 0.65, 0.7, 0.75, 0.8, or 0.85. By limiting the sum of the orthogonal projection areas of each single-crystal perovskite particle 1032 on the first conductive layer 101 and the orthogonal projection area of ​​the perovskite absorber layer 103 on the first conductive layer 101 within a certain range, the light absorption utilization rate of the perovskite absorber layer 103 can be ensured, while the manufacturing cost of the solar cell can be reduced as much as possible.

[0054] In addition, when constructing the perovskite absorber layer 103, the light transmittance requirements for the top cell can also be considered when constructing a stacked solar cell using a perovskite cell as the top cell. Based on the type of bottom cell and the optimal photoelectric conversion efficiency of the stacked solar cell, the ratio of the light-irradiated area of ​​the bottom cell to the area of ​​the light-receiving surface of the bottom cell required for the stacked solar cell to have optimal or good photoelectric conversion efficiency is determined. Based on the determined area ratio, the ratio of the second area to the first area in the perovskite absorber layer 103 is set. For example, if the light-receiving surfaces of the bottom cell and the top cell are the same, the bottom cell needs to transmit 30%, 50%, or 70% of the light from the top cell to reach the bottom cell, which will result in the stacked solar cell having the highest photoelectric conversion efficiency. In this case, the ratio of the second area to the first area in the perovskite absorber layer 103 can be set to 0.7, 0.5, or 0.3, respectively.

[0055] Furthermore, to ensure the photoelectric conversion capacity of the solar cell, a perovskite solar cell can be constructed by selecting single-crystalline perovskite particles 1032 with a bandgap of 1 eV to 2 eV. When a stacked solar cell is constructed using a perovskite cell as the top cell, the photoelectric conversion efficiency of the stacked solar cell is also related to the bandgap of the single-crystalline perovskite particles 1032 in the top cell. In the process of constructing the stacked solar cell, single-crystalline perovskite particles 1032 with a bandgap of 1.4 eV to 1.8 eV can be selected depending on the type of bottom cell. In the process of selecting the single-crystalline perovskite particles 1032, it is sufficient to ensure that the stacked solar cell has good photoelectric conversion efficiency. In the present embodiment, the specific bandgap of the selected single-crystalline perovskite particles 1032 is not limited.

[0056] Therefore, in the process of constructing the stacked solar cell, the ratio between the second area and the first area in the perovskite absorber layer 103 in the perovskite solar cell and the band gap of the single-crystalline perovskite particles 1032 can be controlled according to the need for good photoelectric conversion efficiency achieved by the stacked solar cell, thereby making it possible to maximize the photoelectric conversion efficiency of the stacked solar cell.

[0057] It should be noted that the plurality of single-crystal perovskite particles 1032 may include perovskite particles that do not have a first convex surface and / or a second convex surface, and photogenerated carriers generated in single-crystal perovskite particles 1032 that do not have both a first convex surface and a second convex surface have difficulty completing carrier migration due to the limitations of the adhesive substrate 1031. To further ensure the light utilization efficiency of the perovskite absorption layer 103, in the process of calculating the second area, only the sum of the orthogonal projection areas of each single-crystal perovskite particle 1032, including the first convex surface and the second convex surface, on the first conductive layer 101 may be calculated. Alternatively, the orthogonal projections of all single-crystal perovskite particles 1032 that have a first convex surface and / or a second convex surface on the first conductive layer 101 may be calculated. This is not a limitation in the present embodiment.

[0058] In some embodiments, the thickness of adhesive substrate 1031 is 100 nm or greater.

[0059] As shown in Figures 2 and 4, the thickness h of the adhesive substrate 1031 can be expressed as the distance between two opposing points on the first and second surfaces of the adhesive substrate 1031 along a first direction. One of the important functions of the adhesive substrate 1031 is to fix the single-crystalline perovskite particles 1032 contained and arranged in the adhesive substrate 1031. Therefore, if the thickness h of the adhesive substrate 1031 in the first direction is too small, it becomes difficult to stably fix the single-crystalline perovskite particles 1032, which may result in hidden cracks and reduced stability of the solar cell. At the same time, if the pitch between different carriers is too small, recombination between different carriers may occur, resulting in reduced photoelectric conversion efficiency of the solar cell.

[0060] Therefore, in the manufacturing process of the adhesive substrate 1031, the thickness h of the adhesive substrate 1031 in the first direction needs to be 100 nm or more, and may be, for example, 100 nm, 200 nm, 350 nm, 500 nm, 800 nm, 1 μm, 5 μm, 20 μm, or 50 μm. Setting the thickness h of the adhesive substrate 1031 in the first direction to be sufficiently large ensures that the adhesive substrate 1031 can stably fix the single-crystalline perovskite particles 1032, preventing breakdown of the perovskite absorber layer 103 and improving the stability of the solar cell. At the same time, it ensures a sufficiently large spacing between different carriers, preventing recombination of different carriers, and ensuring the photoelectric conversion efficiency of the solar cell.

[0061] Furthermore, if the thickness h of the adhesive substrate 1031 in the first direction is too large, then in order to give the single-crystalline perovskite particles 1032 a first convex surface and a second convex surface, the size of the single-crystalline perovskite particles 1032, i.e., the maximum distance between any two points on the particle surface, will also increase accordingly, making it more difficult for photogenerated carriers in the single-crystalline perovskite particles 1032 to move, resulting in a decrease in the photoelectric conversion efficiency of the solar cell.

[0062] Therefore, in the process of installing the adhesive substrate 1031, it is necessary to take into consideration not only the fixing effect and carrier isolation effect of the adhesive substrate 1031 on the single-crystalline perovskite particles 1032, but also the effect of the adhesive substrate 1031 on the photoelectric conversion ability of the selected single-crystalline perovskite particles 1032, and to set the thickness h of the adhesive substrate 1031 in the first direction within a range smaller than the size of the single-crystalline perovskite particles 1032 with good photoelectric conversion efficiency, thereby ensuring that the perovskite absorption layer 103 has as good a photoelectric conversion efficiency as possible.

[0063] As shown in FIGS. 2 and 5-7, in some embodiments, the adhesive substrate 1031 includes a light-trapping surface 1033 facing the first carrier transport layer 102 and / or the second conductive layer 104.

[0064] 5 to 7 are cross-sectional views of a solar cell along the vertical direction. In FIG. 5, the light trapping surface 1033 includes only the surface of the adhesive substrate 1031 facing the first carrier transport layer 102. In FIG. 6, the light trapping surface 1033 includes only the surface of the adhesive substrate 1031 facing the second conductive layer 104. In FIG. 7, the light trapping surface 1033 includes both the surface of the adhesive substrate 1031 facing the first carrier transport layer 102 and the surface of the adhesive substrate 1031 facing the second conductive layer 104. Another important function of the adhesive substrate 1031 is to ensure the light absorption ability of the perovskite absorption layer 103. Therefore, in the process of manufacturing the adhesive substrate 1031, a light trapping surface 1033 that enhances the light absorption ability of the perovskite absorption layer 103 can also be manufactured on the adhesive substrate 1031. During the manufacturing process, the light trapping surface 1033 may include only the surface of the adhesive substrate 1031 facing the first carrier transport layer 102, or may include only the surface of the adhesive substrate 1031 facing the second conductive layer 104, or may simultaneously include both the surface of the adhesive substrate 1031 facing the first carrier transport layer 102 and the surface of the adhesive substrate 1031 facing the second conductive layer 104.

[0065] By forming a light trapping surface 1033 on the adhesive substrate 1031 facing the first carrier transport layer 102 and / or the second conductive layer 104, the optical path length of the light irradiated onto the perovskite absorber layer 103 is increased, improving the light absorption ability of the perovskite absorber layer 103 and ultimately increasing the photoelectric conversion efficiency of the perovskite absorber layer 103 and the solar cell.

[0066] As shown in FIGS. 2 and 8, in some embodiments, the light trapping surface 1033 includes a first light trapping structure 31, which extends outside the adhesive substrate 1031 in a first direction.

[0067] 8 is a cross-sectional view of a solar cell in which the light trapping surface 1033 simultaneously includes a surface facing the first carrier transport layer of the adhesive substrate 1031 and a surface facing the second conductive layer 104 of the adhesive substrate 1031, and the light trapping surface 1033 includes a first light trapping structure 31. In the process of manufacturing the light trapping surface 1033 on the adhesive substrate 1031, the first light trapping structure 31 can be formed on the surface facing the first carrier transport layer 102 of the adhesive substrate 1031 and / or the surface facing the second conductive layer 104 of the adhesive substrate 1031, i.e., one or more protrusions extending away from the adhesive substrate 1031 can be formed on the first surface or the second surface. The first light trapping structure 31 is located on the first surface and / or the second surface, and the positional relationship between either surface of the first light trapping structure 31 and the first convex surface and / or the second convex surface of each single-crystalline perovskite particle 1032 in the perovskite absorption layer 103 is contact or separation, and the first light trapping structure 31 does not affect the contact area between the first convex surface and the first carrier transport layer 102 and the contact area between the second convex surface and the second conductive layer 104.

[0068] By forming one or more protrusions extending away from the adhesive substrate 1031 on the first surface or the second surface as the first light trapping structures 31, the first surface and / or the second surface is transformed into a light trapping surface 1033 that has the ability to extend the optical path length of the incident light in the perovskite absorber layer 103, thereby improving the absorption and utilization ability of the perovskite absorber layer 103 for the incident light, and ultimately increasing the photoelectric conversion ability and efficiency of the perovskite absorber layer 103.

[0069] The shapes and sizes of the first light trapping structures 31 may be the same or different, but are not limited to these in the present embodiment.

[0070] As shown in Figures 2 and 9, in some embodiments, the light trapping surface 1033 includes a second light trapping structure 32, and in a first direction, the second light trapping structure 32 is recessed toward the inside of the adhesive substrate 1031.

[0071] 9 is a cross-sectional view of a solar cell in which the light trapping surface 1033 includes both a surface of the adhesive substrate 1031 facing the first carrier transport layer and a surface of the adhesive substrate 1031 facing the second conductive layer 104, and the light trapping surface 1033 includes a second light trapping structure 32. In the process of manufacturing the light trapping surface 1033 on the adhesive substrate 1031, the second light trapping structure 32 can be formed on the surface of the adhesive substrate 1031 facing the first carrier transport layer 102 and / or the second conductive layer 104, i.e., one or more recesses extending into the adhesive substrate 1031 can be formed on the first surface or the second surface. The second light trapping structure 32 is located on the first surface and / or the second surface, and the positional relationship between either surface of the second light trapping structure 32 and the surface located inside the adhesive substrate 1031 of each single-crystal perovskite particle 1032 in the perovskite absorption layer 103 is contact or separation, and the second light trapping structure 32 does not affect the contact area between the single-crystal perovskite particle 1032 and the adhesive substrate 1031.

[0072] By forming one or more recesses extending into the adhesive substrate 1031 on the first or second surface as the second light trapping structures 32, the first and / or second surface is transformed into a light trapping surface 1033 capable of extending the optical path length of incident light in the perovskite absorber layer 103, thereby improving the absorption and utilization ability of the perovskite absorber layer 103 for the incident light, and ultimately increasing the photoelectric conversion ability and efficiency of the perovskite absorber layer 103.

[0073] The light trapping surface 1033 may include only one or more first light trapping structures 31, or may include only one or more second light trapping structures 32, or may include both one or more first light trapping structures 31 and one or more second light trapping structures 32. The light trapping surface 1033 may include only the surface of the adhesive substrate 1031 facing the first carrier transport layer 102, or may include only the surface of the adhesive substrate 1031 facing the second conductive layer 104, or may include both the surface of the adhesive substrate 1031 facing the first carrier transport layer 102 and the surface of the adhesive substrate 1031 facing the second conductive layer 104. The present embodiment does not limit the specific configuration of the light trapping surface 1033 or the type and number of light trapping structures included in the light trapping surface 1033.

[0074] The shapes and sizes of the second light trapping structures 32 may be the same or different, but are not limited to these in the present embodiment.

[0075] In some embodiments, the first carrier transport layer 102 is an electron transport layer or a hole transport layer.

[0076] The role of the first carrier transport layer 102 is to collect and transport carriers generated in the perovskite absorber layer 103. Depending on the operating mechanism of the solar cell, the first carrier transport layer 102 may be either a hole transport layer or an electron transport layer. When the first carrier transport layer 102 is an electron transport layer, the function of the first carrier transport layer 102 includes collecting electrons and transporting them to the first conductive layer 101, outputting electrical energy from the first conductive layer 101, and blocking holes from flowing directly into the first conductive layer 101. When the first carrier transport layer 102 is a hole transport layer, the function of the first carrier transport layer 102 includes blocking electrons from entering the first conductive layer 101, enhancing hole transport, and preventing direct contact between the perovskite absorber layer 103 and the first conductive layer 101. This ensures the photoelectric conversion capacity and electrical energy output of the solar cell.

[0077] The electron transport layer is made of tin oxide (SnOx), titanium dioxide (TiO2), and C 60 The hole transport layer can be composed of materials such as fullerenes and their derivatives, including PCBM, and poly[bis(4-phenyl)(2,4,6-triphenylmethyl)amine] (PTAA), 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenylamino)-9,9′-spirobifluorene (spiro-OMeTAD), nickel oxide (NiOx), or cuprous thiocyanate (CuSCN).

[0078] In some embodiments, the thickness of the first carrier transport layer 102 in the first direction is in the range of 1 nm to 1 μm.

[0079] The core role of the first carrier transport layer 102 is to improve the collection and transport capability of one type of carrier while blocking contact between other carriers and the first conductive layer 101. Therefore, if the thickness of the first carrier transport layer 102 in the first direction is too large, the distance traveled by carriers during transport to the first conductive layer 101 will be too long, leading to carrier recombination, resulting in significant carrier loss and potentially reducing the photoelectric conversion efficiency of the solar cell. If the thickness of the first carrier transport layer 102 in the first direction is too small, the carrier collection and transport capability of the first carrier transport layer 102 will be limited, preventing it from timely collecting and transporting all of the carriers of a certain type generated in the perovskite absorber layer 103, resulting in significant carrier loss and affecting the photoelectric conversion efficiency of the solar cell. At the same time, if the thickness is too small, the blocking capability of other carriers will also be somewhat reduced, leading to recombination of different types of carriers and potentially affecting the photoelectric conversion efficiency of the solar cell.

[0080] Therefore, in the process of constructing the first carrier transport layer 102, the thickness of the first carrier transport layer 102 in the first direction is set to 1 nm to 1 μm, for example, 1 nm, 5 nm, 10 nm, 50 nm, 100 nm, 200 nm, 250 nm, 400 nm, 500 nm, 650 nm, 750 nm, 800 nm, or 950 nm, etc. This ensures that the first carrier transport layer 102 has a sufficiently high collection and transport ability for one type of carrier and a sufficiently high blocking ability for other carriers, thereby reducing carrier loss due to carrier recombination and migration and ensuring the photoelectric conversion efficiency of the solar cell.

[0081] As shown in FIG. 10 , in some embodiments, the solar cell further includes a second carrier transport layer 105 located between the perovskite absorber layer 103 and the second conductive layer 104 and in contact with the perovskite absorber layer 103 and the second conductive layer 104, respectively.

[0082] The second carrier transport layer 105 is similar to the first carrier transport layer 102, and its role is to collect and transport one type of carrier generated in the perovskite absorber layer 103. Depending on the operating mechanism of the solar cell, the second carrier transport layer 105 may be a hole transport layer or an electron transport layer. When the second carrier transport layer 105 is an electron transport layer, its function includes collecting electrons and transporting them to the first conductive layer 101 to output electrical energy from the first conductive layer 101, while blocking holes from flowing directly into the first conductive layer 101. When the second carrier transport layer 105 is a hole transport layer, its function includes blocking electrons from entering the first conductive layer 101, enhancing hole transport, and preventing direct contact between the perovskite absorber layer 103 and the first conductive layer 101. This ensures the photoelectric conversion capacity and electrical energy output of the solar cell.

[0083] In some embodiments, the thickness of the second carrier transport layer 105 in the first direction is comprised between 1 nm and 1 μm.

[0084] The core role of the second carrier transport layer 105 is to improve the collection and transport capability of one type of carrier while blocking contact between other carriers and the first conductive layer 101. Therefore, if the thickness of the second carrier transport layer 105 in the first direction is too large, the distance traveled by the carriers during transport to the second conductive layer 104 will be too long, causing carrier recombination and resulting in significant carrier loss, which may result in a decrease in the photoelectric conversion efficiency of the solar cell. If the thickness of the second carrier transport layer 105 in the first direction is too small, the second carrier transport layer 105 will have limited carrier collection and transport capability and will not be able to timely collect and transport all of the carriers of a certain type generated in the perovskite absorber layer 103, resulting in significant carrier loss and affecting the photoelectric conversion efficiency of the solar cell. At the same time, if the thickness is too small, the blocking capability of other carriers will also be reduced to a certain extent, causing recombination of different types of carriers, which may affect the photoelectric conversion efficiency of the solar cell.

[0085] Therefore, in the process of constructing the second carrier transport layer 105, the thickness of the second carrier transport layer 105 in the first direction is set to 1 nm to 1 μm, for example, 1 nm, 5 nm, 10 nm, 50 nm, 100 nm, 200 nm, 250 nm, 400 nm, 500 nm, 650 nm, 750 nm, 800 nm, or 950 nm, etc. This ensures that the second carrier transport layer 105 has a sufficiently high collection and transport ability for one type of carrier and a sufficiently high blocking ability for other carriers, thereby reducing carrier loss due to carrier recombination and migration and ensuring the photoelectric conversion efficiency of the solar cell.

[0086] In some embodiments, when the first carrier transport layer 102 is a hole transport layer, the second carrier transport layer 105 is an electron transport layer, and when the first carrier transport layer 102 is an electron transport layer, the second carrier transport layer 105 is a hole transport layer.

[0087] To further improve the efficiency of the solar cell, carrier transport layers for collecting and transporting different carriers are provided on opposite sides of the perovskite absorber layer 103 in the first direction, thereby maximizing the photoelectric conversion efficiency and stability of the solar cell.

[0088] As described above, in the solar cell provided in one embodiment of the present application, the perovskite absorber layer 103 of the solar cell is formed using an adhesive substrate 1031 and a plurality of single-crystalline perovskite particles 1032 arranged on the adhesive substrate 1031. Constructing the perovskite absorber layer 103 with single-crystalline perovskite particles 1032 ensures the stability of the perovskite absorber layer 103. Arranging the single-crystalline perovskite particles 1032 on the adhesive substrate 1031 avoids damage to the single-crystalline perovskite during the cutting process and ensures the efficiency of the solar cell. At the same time, constructing the perovskite absorber layer 103 using a single-crystalline particle arrangement contributes to the production of large-area single-crystalline perovskite solar cells. Among the plurality of single-crystal perovskite particles 1032 arranged on the adhesive substrate 1031, at least some of the single-crystal perovskite particles 1032 each have a first convex surface protruding from a first surface of the adhesive substrate 1031 and a second convex surface protruding from a second surface of the adhesive substrate 1031. The perovskite absorption layer 103 is constructed from the single-crystal perovskite particles 1032 exposed on both opposing surfaces of the adhesive substrate 1031, thereby giving the perovskite absorption layer 103 itself a textured structure, which provides better light absorption ability and improves the ability of photogenerated carriers to be transported from the perovskite absorption layer 103 to the conductive layer or carrier transport layer, thereby increasing the photoelectric conversion efficiency and capacity of the solar cell.

[0089] In response to the above, another embodiment of the present application provides a stacked solar cell including a top cell 1001, an adhesive layer 1002, and a bottom cell 1003 stacked in this order, as shown in FIG. 11, where the top cell 1001 is the solar cell described above.

[0090] In some embodiments, the type of bottom cell 1003 includes a crystalline silicon solar cell, a CIGS thin film solar cell, a cadmium telluride thin film solar cell, a III-V thin film solar cell, or a narrow bandgap perovskite thin film solar cell, where the narrow bandgap perovskite thin film solar cell may be a narrow bandgap monocrystalline perovskite thin film solar cell or a narrow bandgap polycrystalline perovskite thin film solar cell.

[0091] In some embodiments, the adhesive layer 1002 includes a mechanical bonding layer made of a conductive adhesive. The conductive adhesive may be formed by adding conductive particles to a transparent adhesive having good light transmittance, such as an adhesive having a transmittance of 80% or more for light of 400 nm or more, or an adhesive having a transmittance of 80% or more for light of 450 nm or more. The conductive adhesive may be a thin, transparent adhesive containing particles with a certain conductive energy, and its transparency may be similar to that of the adhesive, and further description is omitted here. The embodiments of the present application are not limited to a specific type of conductive adhesive.

[0092] Although the present application has been disclosed as above in preferred embodiments, it does not limit the scope of the claims, and any person skilled in the art may make some possible variations and modifications without departing from the idea of ​​the present application, so the protection scope of the present application should be based on the scope limited by the claims of the present application.

[0093] Those skilled in the art will understand that the above embodiments are specific examples of realizing the present application, but that various changes in form and details are possible in practice without departing from the spirit and scope of the present application. Since anyone skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, the scope of protection of the present application should be based on the scope limited by the claims.

Claims

1. a first conductive layer, a first carrier transport layer, a perovskite absorber layer, and a second conductive layer, which are sequentially stacked along a first direction; the perovskite absorber layer includes an adhesive substrate and a plurality of single-crystal perovskite particles arranged on the adhesive substrate, the adhesive substrate having a first surface and a second surface facing each other in the first direction; at least some of the single-crystal perovskite particles have a first convex surface and a second convex surface, the first convex surface protruding relative to the first surface and the second convex surface protruding relative to the second surface; A solar cell characterized by:

2. when any of the single-crystal perovskite particles is defined as a first single-crystal perovskite particle and the single-crystal perovskite particle closest to the first single-crystal perovskite particle is defined as a second single-crystal perovskite particle, the distance between the first single-crystal perovskite particle and the second single-crystal perovskite particle is equal to or less than the maximum width dimension of the first single-crystal perovskite particle; The solar cell according to claim 1 .

3. The maximum distance between any two points on the surface of the single-crystal perovskite particle is 5 μm to 100 μm. The solar cell according to claim 2 .

4. an area of ​​an orthogonal projection of the perovskite absorption layer on the first conductive layer is defined as a first area, an area of ​​an orthogonal projection of the plurality of single-crystal perovskite particles on the first conductive layer is defined as a second area, and a ratio of the second area to the first area is 0.3 to 0.9; The solar cell according to claim 1 .

5. a distance between any one point on the first convex surface and the first surface and / or a distance between any one point on the second convex surface and the second surface in the first direction is equal to or less than half of a maximum length of the single-crystal perovskite particle in the first direction; The solar cell according to claim 1 .

6. In the first direction, the thickness of the adhesive substrate is 100 nm or more. The solar cell according to claim 1 .

7. the adhesive substrate includes a light trapping surface facing the first carrier transport layer and / or the second conductive layer; The solar cell according to claim 1 .

8. the light trapping surface includes a first light trapping structure, the first light trapping structure extending outward from the adhesive substrate in the first direction; The solar cell according to claim 7 .

9. the light trapping surface includes a second light trapping structure, and in the first direction, the second light trapping structure is recessed toward the interior of the adhesive substrate; The solar cell according to claim 7 .

10. the first carrier transport layer is an electron transport layer or a hole transport layer; The solar cell according to claim 1 .

11. In the first direction, the thickness of the first carrier transport layer is in the range of 1 nm to 1 μm. The solar cell according to claim 10 .

12. a second carrier transport layer located between the perovskite absorber layer and the second conductive layer and in contact with the perovskite absorber layer and the second conductive layer, respectively; The solar cell according to claim 1 .

13. In the first direction, the thickness of the second carrier transport layer is in the range of 1 nm to 1 μm. The solar cell according to claim 12 .

14. When the first carrier transport layer is a hole transport layer, the second carrier transport layer is an electron transport layer; When the first carrier transport layer is an electron transport layer, the second carrier transport layer is a hole transport layer. The solar cell according to claim 12 .

15. The solar cell includes a top cell, an adhesive layer, and a bottom cell, which are stacked in this order, and wherein the top cell is the solar cell according to any one of claims 1 to 14. A stacked solar cell characterized by:

16. the bottom cell comprises a crystalline silicon solar cell, a CIGS thin film solar cell, a cadmium telluride thin film solar cell, a III-V thin film solar cell, or a narrow bandgap perovskite thin film solar cell; The stacked solar cell according to claim 15 .

17. The adhesive layer includes a mechanical bonding layer made of a conductive adhesive. The stacked solar cell according to claim 15 .

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