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 to 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 THEINVENTION 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, abundant in resources, etc. For this reason, solar energy is gradually replacing fossil energy as the core clean energy, and solar cells have become the most important part of clean energy utilization because of their good photoelectric conversion efficiency.

[0004] One of the key factors affecting the proportion of solar energy in energy utilization is the photoelectric conversion efficiency of solar cells. In order 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 including 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 including an adhesive substrate and a plurality of single crystal perovskite particles arranged on the adhesive substrate, the adhesive substrate including 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] Also, for any one of the single crystal perovskite particles, the distance between the current single crystal perovskite particle and an adjacent one of the single crystal perovskite particles is equal to or less than the maximum distance between any two points on the surface of the current single crystal perovskite particle.

[0009] Furthermore, 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 point on the first convex surface and the first surface and / or the distance between any 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 outwardly of the adhesive substrate in the first direction.

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

[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 includes a range of 1 nm to 1 μm.

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

[0019] Furthermore, 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 adhesion layer and a bottom cell stacked in sequence, where the top cell is the above-mentioned solar cell.

[0022] Also, the bottom cell 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 band gap perovskite thin film solar cell.

[0023] The adhesive layer also includes a mechanical lamination layer made of a conductive adhesive. Effect 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 construction process provided in the present embodiment, an adhesive substrate and a plurality of single crystal perovskite particles arranged on the adhesive substrate are used to form the perovskite absorption layer of the solar cell. The perovskite absorption layer is constructed with single crystal perovskite particles to ensure the stability of the perovskite absorption layer. The single crystal perovskite particles are arranged on the adhesive substrate to avoid damage to the single crystal perovskite during the cutting process and ensure the efficiency of the solar cell. The perovskite absorption layer is constructed in the manner of arranging single crystal particles, which contributes to the production of large-area single crystal 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. A perovskite absorption layer is constructed with the single-crystal perovskite particles exposed on both opposing surfaces of the adhesive substrate, thereby giving the perovskite absorption layer 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 to the conductive layer or carrier transport layer, thereby improving the photoelectric conversion efficiency and capacity of the solar cell. [Brief description of the drawings]

[0026] One or more embodiments are illustratively illustrated in corresponding accompanying drawing figures; however, 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 a structure of a solar cell according to an embodiment of the present application. [Diagram 2] FIG. 2 is a cross-sectional view of a solar cell according to an embodiment of the present application. [Diagram 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. [Diagram 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 in accordance with an embodiment of the present application. [Figure 9] FIG. 9 is a cross-sectional view of another solar cell in accordance with 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 an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] As can be seen from the background art, perovskite solar cells have good prospects due to the 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 absorption 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. The perovskite absorption layer is constructed using single-crystalline perovskite particles to ensure the stability of the perovskite absorption layer. The single-crystalline perovskite particles are arranged on the adhesive substrate to avoid damage to the single-crystalline perovskite during the cutting process and ensure the efficiency of the solar cell. The perovskite absorption layer is constructed in a single-crystalline particle arrangement manner, which contributes to the manufacture 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. A perovskite absorption layer is constructed with the single-crystal perovskite particles exposed on both opposing surfaces of the adhesive substrate, thereby giving the perovskite absorption layer 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 to the conductive layer or carrier transport layer, thereby improving 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 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 in order to allow the reader to understand the present application better, 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, an 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 includes a first conductive layer 101, a first carrier transport layer 102, a perovskite absorption layer 103 and a second conductive layer 104 which are sequentially stacked along a first direction, the perovskite absorption layer 103 including an adhesive substrate 1031 and a plurality of single crystal perovskite particles 1032 arranged on the adhesive substrate 1031, the adhesive substrate 1031 including 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. Thus, the adhesive substrate 1031 can be constructed of a transparent curable adhesive or colloid. For example, the adhesive substrate 1031 can be constructed of an ultraviolet curable adhesive such as an acrylic adhesive or a resin adhesive or other types of curable transparent adhesive. Here, transparency refers to having good light transmittance for visible light, for example, having a transmittance of 80% or more for light of 400 nm or more, or having a transmittance of 75% or more for light of 450 nm or more.

[0033] The solar cell absorbs light irradiated to the solar cell through the perovskite absorption layer 103, then generates photo-generated carriers by the single crystal perovskite particles 1032, collects different photo-generated carriers by 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 the operation of the solar cell, the photoelectric conversion efficiency of the battery cell is mainly affected by the generation ability of photo-generated carriers and the collection and utilization ability of photo-generated carriers. In the process of constructing the perovskite absorber layer 103, the perovskite absorber layer 103 is constructed with an adhesive substrate 1031 and a plurality of single-crystal perovskite particles 1032 arranged on the adhesive substrate 1031, thereby ensuring the integrity of the single-crystal perovskite particles 1032, avoiding damage to the single-crystal perovskite material in the process of constructing the perovskite absorber layer 103, and ensuring the generation ability of photo-generated carriers of the perovskite absorber layer 103.

[0035] In addition, the perovskite absorber layer 103 is constructed with the single crystal perovskite particles 1032, which reduces the decomposition rate of the perovskite absorber layer 103 during the operation of the cell, and ensures 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, so that the solar cell has a higher photoelectric conversion efficiency and service life.

[0036] At the same time, constructing the perovskite absorber layer 103 by arranging the single crystal perovskite particles 1032 on the adhesive substrate 1031 is helpful to simply and efficiently manufacture a large-area perovskite absorber layer 103, which breaks through the constraints imposed by the production efficiency of the single crystal perovskite raw materials on the perovskite absorber layer 103 and the area of ​​the perovskite solar cell, greatly improves the production efficiency of large-area perovskite solar cells with good stability, and enhances the application prospects of single crystal perovskite solar cells.

[0037] 2, in the first direction, the adhesive substrate 1031 includes a first surface and a second surface facing each other, and at least some of the single-crystal perovskite particles 1032 have a first convex surface and a second convex surface, the first convex surface protruding toward the first surface, and the second convex surface protruding toward the second surface. In the process of constructing the perovskite absorption layer 103, it is ensured that at least some of the single-crystal perovskite particles 1032 have a first convex surface and a second convex surface protruding from the surface on two opposing surfaces of the adhesive substrate 1031, respectively, that is, at least some of the single-crystal perovskite particles 1032 penetrate the adhesive substrate 1031 to contact the first carrier transport layer 102 and the second conductive layer 104. At least some of the single-crystal perovskite particles 1032 have a first convex surface and a second convex surface, so that the two opposing surfaces of the perovskite absorption layer 103 are textured, which improves the light absorption ability of the perovskite absorption layer 103. At the same time, at least some of the single-crystal perovskite particles 1032 penetrate the adhesive substrate 1031 and contact the first carrier transport layer 102 and the second conductive layer 104, so that after generating the photo-generated carriers, the difficulty of the photo-generated carriers moving to the first carrier transport layer 102 and the second conductive layer 104 is greatly reduced, which improves the light-generated carrier transport ability of the perovskite absorption layer 103. As a result, the photoelectric conversion efficiency of the perovskite absorption layer 103 is improved from both the light absorption ability and the carrier transport ability.

[0038] In addition, 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 limited in the present embodiment. For the sake of convenience of understanding and explanation, the present embodiment will be described using the example in which the perovskite particles are spherical. In the actual use process, the shape of the single crystal perovskite particles 1032 may be adjusted as necessary. This is not limited in the present embodiment.

[0039] In addition, the single crystal perovskite particles 1032 contained in the perovskite absorption 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 one or more types of particles having no first convex surface or no second convex surface. This is not limited in the embodiments of the present application.

[0040] Furthermore, each single crystal perovskite particle 1032 in the perovskite absorption layer 103 may be arranged in a regular array, such as a rectangle, an approximate rectangle, a circle, an ellipse, etc., in the adhesive substrate 1031 at a certain interval, which can improve the uniformity of the light absorption and carrier output of the perovskite absorption layer 103. Also, they may be freely arranged in any interval and order on the adhesive substrate 1031. This is not limited in the embodiments of the present application.

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

[0042] As shown in FIG. 3, the two largest circles in the figure are circles formed through the spherical centers of two adjacent single-crystal perovskite particles 1032 along the horizontal direction, the maximum distance between any two points on the surface of the current single-crystal perovskite particle is d, and the distance between the current single-crystal perovskite particle and the adjacent single-crystal perovskite particle 1032 is D, where D can indicate the minimum distance between any one point on the surface of the current single-crystal perovskite particle and any one point on the surface of the adjacent single-crystal perovskite particle 1032. If the distance between the two adjacent single-crystal perovskite particles 1032 is too large, the absorption ability of the perovskite absorption layer 103 for the light irradiated to the region between the two adjacent single-crystal perovskite particles 1032 will be extremely poor, and the absorption ability of the perovskite absorption layer 103 for the light will be reduced, affecting the photoelectric conversion ability of the perovskite absorption layer 103.

[0043] On the other hand, since the light absorption ability of the single crystal perovskite particles 1032 gradually decreases as the distance between itself and the light increases, it is necessary to limit the distance D between two adjacent single crystal perovskite particles 1032 in the perovskite absorption layer 103, and the distance D between the current single crystal perovskite particle and the adjacent single crystal perovskite particle 1032 is set within a range smaller than the size of the current perovskite particle, i.e., within a range smaller than the maximum distance d between any two points on the surface of the current single crystal perovskite particle, for example, D may be set to 0.1d, 0.2d, 0.35d, 0.45d, 0.5d, 0.75d or 0.9d, etc. By setting the distance between the current single crystal perovskite particle and the adjacent single crystal perovskite particle 1032 within a range equal to or less 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 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 the perovskite absorber layer 103 formed along the vertical direction through the spherical centers of three equal-sized single-crystal perovskite particles 1032. In the perovskite absorber layer 103, in the first direction, the maximum value of the distance between any one point on the first convex surface of the single-crystal perovskite particle 1032 and the first surface of the adhesive substrate 1031 is the distance a between the point A farthest from the first surface on the first convex surface and the first surface; similarly, the maximum value of the distance between any one point on the second convex surface of the single-crystal perovskite particle 1032 and the second surface of the adhesive substrate 1031 is the distance b between the point B farthest from the second surface on the second convex surface and the first 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 crystal perovskite particles 1032, and in order to ensure the fixing effect, the adhesive substrate 1031 has a certain thickness. Meanwhile, in the process of generating carriers in the single crystal perovskite particles 1032, different carriers are collected and moved at both ends of the single crystal perovskite particles 1032, respectively, and when the distance a between point A on the first convex surface of the single crystal perovskite particle 1032 and the first surface is 1 / 2 or more of L, and / or the distance b between point B on the second convex surface and the second surface is 1 / 2 or more of L, the carriers collected in the first carrier transport layer 102 or the second conductive layer 104 may recombine with anisotropic carriers, which may lead to a decrease in the photoelectric conversion efficiency of the perovskite absorption layer 103.

[0047] Therefore, in the process of constructing the perovskite absorption layer 103, for the single crystal perovskite particle 1032 including the first convex surface and the 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 less than half the maximum length in the first direction of the single crystal perovskite particle 1032. For example, the distance a and / or the distance b are 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, and the photoelectric conversion efficiency of the solar cell is ensured.

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

[0049] In the process of constructing the perovskite absorption layer 103, if the size of the selected single crystal perovskite particles 1032 is too large, i.e., the maximum distance d between any two points on the particle surface is too large, then after constructing the perovskite absorption layer with the single crystal perovskite particles 1032, the distance required for the carriers to move to the first carrier transport layer 102 or the second conductive layer 104 after absorbing light energy to generate carriers is too large, making it difficult to complete the movement of the carriers, 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 in the process of the carriers moving, the pitch between different carriers is small, making it easy for carriers to recombine, resulting in a decrease in the photoelectric conversion efficiency of the solar cell. In addition, if the size of the single crystal perovskite particles 1032 is too small, the thickness of the perovskite absorption layer 103 will also be small, and the probability of the single crystal perovskite particles 1032 being decomposed due to the potential difference between the two sides will increase significantly, resulting in a decrease in the stability of the solar cell.

[0050] Therefore, in the process of constructing the perovskite absorption 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 and constructed, 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 absorption layer 103. While ensuring that the carriers in the perovskite absorption layer 103 can easily move, the probability of recombination between different carriers and the probability of decomposition of the single crystal perovskite particles 1032 are reduced, and the photoelectric conversion efficiency and stability of the solar cell are ensured.

[0051] In some embodiments, the area of ​​the orthogonal projection of the perovskite absorption layer 103 on the first conductive layer 101 is defined as a 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 a 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 absorption layer 103, the light absorption area when the perovskite absorption layer 103 performs photoelectric conversion can be regarded as the sum of the orthogonal projection areas of all the single crystal perovskite particles 1032 in the first conductive layer 101, that is, the second area. Meanwhile, the area where the perovskite absorption layer 103 receives light can be regarded as the orthogonal projection area of ​​the perovskite absorption layer 103 in the first conductive layer 101, that is, the first area. If the ratio of the second area to the first area is too small, the absorption utilization rate of the perovskite absorption layer 103 for the light irradiated to the perovskite absorption layer 103 is low, which leads to a weak photoelectric conversion ability of the solar cell, and makes it difficult to effectively perform photoelectric conversion. Due to limitations in the photoelectric conversion ability 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 to the perovskite absorption layer 103. When the ratio of the second area to the first area is too large, the perovskite absorption layer 103 contains single crystal perovskite particles 1032 whose photoelectric conversion ability is not fully utilized, resulting in poor cost performance between the manufacturing cost of the solar cell and its photoelectric conversion ability.

[0053] Therefore, in the process of constructing the perovskite absorption 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 absorption layer 103 on the first conductive layer 101 and the area of ​​the orthogonal projection of the perovskite absorption 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 area of ​​the orthogonal projection of the perovskite absorption layer 103 on the first conductive layer 101 within a certain range, the light absorption utilization rate of the perovskite absorption layer 103 is ensured, and at the same time, the manufacturing cost of the solar cell is reduced as much as possible.

[0054] In addition, in the process of constructing the perovskite absorption layer 103, the light transmittance needs for the top cell when constructing a stacked solar cell with the perovskite cell as the top cell can also be referred to. Based on the type of the bottom cell and the optimal photoelectric conversion efficiency of the stacked solar cell, the ratio of the light irradiation area required for the bottom cell and the area of ​​the bottom cell light receiving surface when the stacked solar cell has 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 absorption layer 103 is set. For example, when the areas of the light receiving surfaces of the bottom cell and the top cell are consistent, when the bottom cell needs to transmit 30%, 50% or 70% of the light from the top cell to reach the bottom cell, the stacked solar cell has the highest photoelectric conversion efficiency, in this case, the ratio of the second area to the first area in the perovskite absorption layer 103 can be set to 0.7, 0.5, and 0.3, respectively.

[0055] In addition, in order to ensure the photoelectric conversion ability of the solar cell, the single crystal perovskite particles 1032 having a band gap of 1 eV to 2 eV can be selected to construct a perovskite solar cell. When constructing a stacked solar cell with a perovskite cell as the top cell, the photoelectric conversion efficiency of the stacked solar cell is also related to the band gap of the single crystal perovskite particles 1032 in the top cell. In the process of constructing the stacked solar cell, the single crystal perovskite particles 1032 having a band gap of 1.4 eV to 1.8 eV can be selected to construct a perovskite cell according to the type of the bottom cell. In the process of selecting the single crystal perovskite particles 1032, it is sufficient to provide the stacked solar cell with good photoelectric conversion efficiency. In the present embodiment, the specific band gap of the single crystal perovskite particles 1032 selected is not limited.

[0056] Thus, in the process of constructing the stacked solar cell, the ratio between the second area and the first area in the perovskite absorption layer 103 in the perovskite solar cell and the band gap of the single crystal 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] In addition, the plurality of single crystal perovskite particles 1032 may include perovskite particles that do not have the first convex surface and / or the second convex surface, and the photogenerated carriers generated in the single crystal perovskite particles 1032 that do not have both the first convex surface and the second convex surface are difficult to complete the carrier movement due to the restriction of the adhesive substrate 1031. In order to further ensure the light utilization rate of the perovskite absorption layer 103, in the process of statistically 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 statistically calculated. In addition, the orthogonal projections of all single crystal perovskite particles 1032 that have the first convex surface and / or the second convex surface on the first conductive layer 101 may be statistically calculated. In the embodiment of the present application, this is not limited.

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

[0059] As shown in FIG. 2 and FIG. 4, the thickness h of the adhesive substrate 1031 can be represented by the distance between two points facing each other along the first direction on the first and second surfaces of the adhesive substrate 1031. One of the important functions of the adhesive substrate 1031 is to fix the single crystal perovskite particles 1032 accommodated and fixedly arranged in the adhesive substrate 1031. Thus, if the thickness h of the adhesive substrate 1031 in the first direction is too small, it becomes difficult to stably fix the single crystal perovskite particles 1032, and hidden cracks may occur, which may lead to a decrease in the stability of the solar cell. At the same time, if the pitch between different carriers is too small, recombination between different carriers may occur, which may lead to a decrease in the photoelectric conversion efficiency of the solar cell.

[0060] Therefore, in the process of manufacturing the adhesive substrate 1031, the thickness h of the adhesive substrate 1031 in the first direction needs to be 100 nm or more, for example, it may be 100 nm, 200 nm, 350 nm, 500 nm, 800 nm, 1 μm, 5 μm, 20 μm or 50 μm, etc. By setting the thickness of the adhesive substrate 1031 in the first direction to be sufficiently large, it is possible to ensure that the adhesive substrate 1031 stably fixes the single crystal perovskite particles 1032, avoid the failure of the perovskite absorption layer 103, and increase the stability of the solar cell, while at the same time ensuring a sufficiently large interval between different carriers, avoiding the 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 crystal perovskite particle 1032 a first convex surface and a second convex surface, the size of the single crystal perovskite particle 1032, i.e., the maximum distance between any two points on the particle surface, will also become correspondingly large, making it more difficult for photogenerated carriers in the single crystal perovskite particle 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 crystal perovskite particles 1032, but also the influence of the adhesive substrate 1031 on the photoelectric conversion ability of the selected single crystal 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 crystal perovskite particles 1032 with good photoelectric conversion efficiency, thereby ensuring that the perovskite absorption layer 103 has as good photoelectric conversion efficiency as possible.

[0063] As shown in FIGS. 2, 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 along the vertical direction of the solar cell, and the light trapping surface 1033 in FIG. 5 includes only the surface facing the first carrier transport layer 102 of the adhesive substrate 1031, the light trapping surface 1033 in FIG. 6 includes only the surface facing the second conductive layer 104 of the adhesive substrate 1031, and the light trapping surface 1033 in FIG. 7 includes the surface facing the first carrier transport layer 102 of the adhesive substrate 1031 and the surface facing the second conductive layer 104 of the adhesive substrate 1031. 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 in the perovskite absorption layer 103 of the light irradiated to the perovskite absorption layer 103 is increased, improving the light absorption ability of the perovskite absorption layer 103 and ultimately increasing the photoelectric conversion efficiency of the perovskite absorption 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 in a direction 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 one of the surfaces 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 structure 31, the first surface and / or the second surface is modified into a light trapping surface 1033 capable of extending the optical path length of the incident light in the perovskite absorption layer 103, improving the absorption and utilization ability of the perovskite absorption layer 103 for the incident light, and thus enhancing the photoelectric conversion ability and efficiency of the perovskite absorption layer 103.

[0069] The shapes and sizes of the first light trapping structures 31 may be the same or different, but are not limited thereto 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, which is recessed towards the inside of the adhesive substrate 1031 in the first direction.

[0071] 9 is a cross-sectional view of a solar cell in which the light trapping surface 1033 includes both 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 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 one of the surfaces 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 structure 32, the first and / or second surface is transformed into a light trapping surface 1033 capable of extending the optical path length of the incident light in the perovskite absorption layer 103, improving the absorption and utilization ability of the perovskite absorption layer 103 for the incident light, and thus enhancing the photoelectric conversion ability and efficiency of the perovskite absorption layer 103.

[0073] It should be noted that the light trapping surface 1033 may include only one or more first light trapping structures 31, may include only one or more second light trapping structures 32, or may include 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 a surface facing the first carrier transport layer 102 of the adhesive substrate 1031, may include only a surface facing the second conductive layer 104 of the adhesive substrate 1031, or may include a surface facing the first carrier transport layer 102 of the adhesive substrate 1031 and a surface facing the second conductive layer 104 of the adhesive substrate 1031. The embodiment of the present application does not limit the specific configuration of the light trapping surface 1033 and 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 thereto 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 absorption layer 103. Based on the operation mechanism of the solar cell, the first carrier transport layer 102 may be 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, transporting the collected electrons to the first conductive layer 101, outputting electrical energy in the first conductive layer 101, and blocking holes so that they do not flow directly to 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 the entry of electrons into the first conductive layer 101, enhancing the transport of holes, and preventing the perovskite absorption layer 103 and the first conductive layer 101 from directly contacting each other. This ensures the photoelectric conversion ability 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 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 includes 1 nm to 1 μm.

[0079] The core role of the first carrier transport layer 102 is to improve the collection and transport ability of one type of carrier, while blocking the contact of other carriers with the first conductive layer 101. Therefore, if the thickness of the first carrier transport layer 102 in the first direction is too large, the moving distance of the carriers in the process of being transported to the first conductive layer 101 is too large, which may cause carrier recombination, resulting in large carrier loss, and resulting in a decrease in 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 collection and transport ability of the first carrier transport layer 102 for carriers is limited, and a certain type of carrier generated in the perovskite absorption layer 103 cannot be collected and transported in a timely manner, resulting in large carrier loss, which affects the photoelectric conversion efficiency of the solar cell; at the same time, if the thickness is too small, the blocking ability for other carriers is also reduced to a certain extent, which may cause recombination of different types of carriers, which may affect 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. The first carrier transport layer 102 can ensure that it 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 a type of carrier generated in the perovskite absorption layer 103. Based on the operation 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, the function of the second carrier transport layer 105 includes collecting electrons, transporting the collected electrons to the first conductive layer 101, outputting electrical energy in the first conductive layer 101, and blocking holes from flowing directly to the first conductive layer 101. When the second carrier transport layer 105 is a hole transport layer, the function of the second carrier transport layer 105 includes blocking the entry of electrons into the first conductive layer 101, enhancing the transport of holes, and preventing the perovskite absorption layer 103 from directly contacting the first conductive layer 101. This ensures the photoelectric conversion ability 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 ability of one type of carrier, while blocking the contact of other carriers with the first conductive layer 101. Therefore, if the thickness of the second carrier transport layer 105 in the first direction is too large, the moving distance of the carriers in the process of being transported to the second conductive layer 104 is too large, which may cause carrier recombination, resulting in large carrier loss, and resulting 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 has limited collection and transport ability for carriers, and cannot timely collect and transport all of a certain type of carrier generated in the perovskite absorption layer 103, resulting in large carrier loss, affecting the photoelectric conversion efficiency of the solar cell; at the same time, if the thickness is too small, the blocking ability for other carriers will also be reduced to a certain extent, which may cause 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. The second carrier transport layer 105 can ensure that it 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] In order 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, so as to maximize 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 adhesive substrate 1031 and a plurality of single crystal perovskite particles 1032 arranged on the adhesive substrate 1031 are used to form the perovskite absorption layer 103 of the solar cell. By constructing the perovskite absorption layer 103 with the single crystal perovskite particles 1032, the stability of the perovskite absorption layer 103 is ensured. By using the form in which the single crystal perovskite particles 1032 are arranged on the adhesive substrate 1031, damage to the single crystal perovskite in the cutting process is avoided and the efficiency of the solar cell is ensured. At the same time, by constructing the perovskite absorption layer 103 in the manner of arranging single crystal particles, it is possible to manufacture a large-area single crystal perovskite solar cell. Among the multiple 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, so that the perovskite absorption layer 103 itself has 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 improving 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 adhesion layer 1002 and a bottom cell 1003 stacked in sequence 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 lamination layer made of a conductive adhesive. Here, the conductive adhesive may be formed by adding conductive particles to a transparent adhesive having good transmittance to light, for example, 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 transparent thin adhesive containing particles with a certain conductive energy, and the transparency may be similar to that of the adhesive, and the description will be omitted here. In the embodiments of the present application, the specific type of conductive adhesive is not limited.

[0092] Although the present application has been disclosed 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 for implementing 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 any person 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. The semiconductor device 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 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. for any one of said single-crystal perovskite particles, the spacing between the current single-crystal perovskite particle and an adjacent one of said single-crystal perovskite particles is less than or equal to the maximum spacing between any two points on the surface of said current 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. 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; The solar cell according to claim 1 .

5. In the first direction, 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 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 outwardly of 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, the second light trapping structure being recessed toward an interior of the adhesive substrate in the first direction; 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 the top cell is the solar cell according to any one of claims 1 to 14. A stacked solar cell comprising:

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 band gap perovskite thin film solar cell; The stacked solar cell according to claim 15 .

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

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