Perovskite layer preparation method, perovskite laminated solar cell, and preparation method therefor

Abstract

The present disclosure provides a perovskite layer preparation method, a perovskite laminated solar cell, and a preparation method thereof. The perovskite layer preparation method comprises the following steps: providing a substrate and a gas-permeable heat conduction layer; preparing a lead halide framework layer on a surface of the substrate, and preparing a perovskite intermediate structure on the lead halide framework layer; inverting the perovskite intermediate structure, and oppositely arranging the perovskite intermediate structure and the gas-permeable heat conduction layer; performing annealing treatment on the inverted perovskite intermediate structure.

Description

Preparation method of perovskite layer, perovskite tandem solar cell and preparation method thereof

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on November 1, 2023, with application number 202311453225.8 and public name “Method for preparing perovskite layer, perovskite tandem solar cell and its preparation method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the technical field of solar cells, and in particular to a method for preparing a perovskite layer, a perovskite stacked solar cell and a preparation method thereof. Background Art

[0003] Perovskite tandem solar cells can break through the theoretical efficiency limit of traditional pure silicon photovoltaic cells and further improve the photoelectric conversion efficiency of solar cells. However, the perovskite layer in perovskite tandem solar cells has problems such as excessive lead iodide residue, poor crystallinity, and numerous crystal defects, which limit the further improvement of the photoelectric conversion efficiency of perovskite tandem solar cells.

[0004] Summary of the Invention

[0005] In a first aspect, the present disclosure provides a method for preparing a perovskite layer, the method comprising the following steps:

[0006] Providing a substrate having a first suede surface and a breathable heat-conductive layer respectively;

[0007] A conformal lead halide skeleton layer is prepared on the surface of the substrate, and a cationic solution is coated on the lead halide skeleton layer to obtain a perovskite intermediate structure having a second velvet surface; wherein the cationic solution includes a volatile solvent and a cationic agent dissolved in the volatile solvent;

[0008] Inverting the perovskite intermediate structure and arranging it opposite to the breathable heat-conducting layer so that a restricted area is formed between the second velvet surface and the breathable heat-conducting layer;

[0009] The inverted perovskite intermediate structure is annealed to obtain the perovskite layer.

[0010] In some embodiments of the present disclosure, the restricted area is the area formed between the second velvet surface of the inverted perovskite intermediate structure and the opposite breathable thermal conductive layer, and the tip of the second velvet surface of the inverted perovskite intermediate structure is close to or abuts against the breathable thermal conductive layer.

[0011] In some embodiments of the present disclosure, the breathable heat-conducting layer has holes therein, and the pore diameter of the holes in the breathable heat-conducting layer is 0.1 μm to 10 μm.

[0012] In some embodiments of the present disclosure, the breathable heat-conductive layer includes one or more of filter paper, glass sheet, polymer film, porous metal material and porous ceramic material.

[0013] In some embodiments of the present disclosure, the first velvet surface is a pyramid velvet surface, wherein the size of the pyramid structure is 1 μm to 6 μm.

[0014] In some embodiments of the present disclosure, the annealing treatment is performed at a temperature of 120° C. to 170° C. and for a time of 20 min to 30 min.

[0015] In some embodiments of the present disclosure, the volatile solvent includes one or both of ethanol and isopropanol.

[0016] In some embodiments of the present disclosure, the volatile solvent includes the ethanol and the isopropanol, and the mass ratio of the ethanol to the isopropanol is 1:(0.5-2).

[0017] In some embodiments of the present disclosure, the volatile solvent consists of the ethanol and the isopropanol.

[0018] In some embodiments of the present disclosure, the cations in the cationic reagent include one or more of methylammonium, formamidine and cesium ions, and the anions in the cationic reagent include one or more of chloride, bromide and iodide ions.

[0019] In some embodiments of the present disclosure, the lead halide skeleton layer includes at least lead iodide.

[0020] In some embodiments of the present disclosure, the lead halide skeleton layer is prepared by an evaporation method.

[0021] In some embodiments of the present disclosure, the thickness of the lead halide skeleton layer is 300 nm to 400 nm, and the thickness of the perovskite layer is 450 nm to 550 nm.

[0022] In a second aspect, the present disclosure further provides a perovskite tandem solar cell, wherein the perovskite tandem solar cell comprises a perovskite layer, and the perovskite layer is prepared by the preparation method of the perovskite layer as described in any of the above embodiments.

[0023] In some embodiments of the present disclosure, the perovskite tandem solar cell includes:

[0024] Texturing silicon substrate battery;

[0025] A first transparent conductive layer stacked on the front surface of the silicon substrate cell;

[0026] A hole transport layer stacked on the first transparent conductive layer on a side away from the texturing silicon substrate cell;

[0027] The perovskite layer is stacked on the side of the hole transport layer away from the texturing silicon substrate cell;

[0028] An electron transport layer stacked on the side of the perovskite layer facing away from the texturing silicon substrate cell;

[0029] A second transparent conductive layer stacked on the electron transport layer at a side away from the textured silicon substrate cell;

[0030] A first electrode and a second electrode, wherein the second electrode forms an ohmic contact with the second transparent conductive layer, and the first electrode forms an ohmic contact with the silicon substrate cell.

[0031] In some embodiments of the present disclosure, the thickness of the first transparent conductive layer is 80 nm to 100 nm.

[0032] In some embodiments of the present disclosure, the hole transport layer has a thickness of 20 nm to 30 nm.

[0033] In some embodiments of the present disclosure, the thickness of the electron transport layer is 15 nm to 25 nm.

[0034] In some embodiments of the present disclosure, the thickness of the second transparent conductive layer is 80 nm to 130 nm.

[0035] In some embodiments of the present disclosure, the thickness of the first electrode is 300 nm to 350 nm.

[0036] In some embodiments of the present disclosure, the thickness of the second electrode is 300 nm to 350 nm.

[0037] In some embodiments of the present disclosure, the material of the first transparent conductive layer is indium zinc oxide or indium tin oxide.

[0038] In some embodiments of the present disclosure, the material of the hole transport layer is nickel oxide; and / or the material of the electron transport layer is C 60 .

[0039] In some embodiments of the present disclosure, the material of the second transparent conductive layer is indium zinc oxide or indium tin oxide.

[0040] In some embodiments of the present disclosure, the material of the first electrode is silver.

[0041] In some embodiments of the present disclosure, the material of the second electrode is silver.

[0042] In some embodiments of the present disclosure, a buffer layer is provided between the electron transport layer and the second transparent conductive layer, and the thickness of the buffer layer is 20 nm to 30 nm.

[0043] In a third aspect, the present disclosure further provides a method for preparing a perovskite tandem solar cell, the method comprising: preparing a perovskite layer by using the method for preparing a perovskite layer as described in any of the above embodiments.

[0044] In some embodiments of the present disclosure, the preparation method comprises the following steps:

[0045] Provide texturing silicon substrate battery;

[0046] Prepare a first transparent conductive layer on the front side of the texturing silicon substrate cell;

[0047] preparing a hole transport layer on the first transparent conductive layer;

[0048] preparing a perovskite layer by using the method for preparing a perovskite layer as described in any of the above embodiments;

[0049] preparing an electron transport layer on the perovskite layer;

[0050] preparing a second transparent conductive layer on the electron transport layer;

[0051] A second electrode is prepared on the second transparent conductive layer, and a first electrode is prepared on the back side of the texturing silicon substrate cell.

[0052] In some embodiments of the present disclosure, the first transparent conductive layer is prepared by physical vapor deposition, the hole transport layer is prepared by physical vapor deposition, the electron transport layer is prepared by evaporation, and the second transparent conductive layer is prepared by physical vapor deposition. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0054] FIG1 is a schematic diagram of an annealing method in the preparation process of a perovskite layer in the related art;

[0055] FIG2 is a schematic diagram of an annealing method during the preparation of a perovskite layer disclosed in an embodiment of the present invention;

[0056] FIG3 is a schematic diagram of the structure of a perovskite tandem solar cell disclosed in an embodiment of the present invention;

[0057] FIG4 is a schematic diagram of the SEM morphology of the perovskite layer according to Example 1 of the present invention;

[0058] FIG5 is another SEM morphology diagram of the perovskite layer of Example 1 of the present invention

[0059] FIG6 is a schematic diagram of the SEM morphology of the perovskite layer according to the third embodiment of the present invention;

[0060] FIG7 is a schematic diagram of the SEM morphology of the perovskite layer of Comparative Example 1.

[0061] Icon: 1. Textile silicon substrate battery; 2. First transparent conductive layer; 3. Hole transport layer; 4. Perovskite layer; 5. Electron transport layer; 6. Buffer layer; 7. Second transparent conductive layer; 8. First electrode; 9. Second electrode. DETAILED DESCRIPTION

[0062] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0063] In the present invention, terms such as "upper," "lower," "left," "right," "front," "back," "top," "bottom," "inner," "outer," "center," "vertical," "horizontal," "transverse," and "longitudinal" indicate positions or locations based on the positions or locations shown in the accompanying drawings. These terms are primarily intended to better describe the present invention and its embodiments and are not intended to limit the devices, elements, or components indicated to having a specific orientation, or to being constructed or operated in a specific orientation.

[0064] Furthermore, some of the above terms may be used to express other meanings besides indicating a position or location. For example, the term "on" may also be used to indicate a dependency or connection in certain circumstances. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0065] Furthermore, the terms "installed," "disposed," "provided with," "connected," and "connected" should be interpreted broadly. For example, they can refer to fixed connections, removable connections, or integral structures; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; or internal communication between two devices, elements, or components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on specific circumstances.

[0066] Furthermore, the terms "first," "second," and the like are primarily used to distinguish between different devices, elements, or components (which may or may not be of the same type and configuration), and are not intended to indicate or imply the relative importance or quantity of the devices, elements, or components indicated. Unless otherwise specified, "plurality" means two or more.

[0067] Currently, when preparing a perovskite layer, a lead halide skeleton layer of a certain thickness is generally first prepared on a substrate. A cationic solution is then coated on the lead halide skeleton layer, followed by direct annealing (see Figure 1 for the annealing method, where the direction of the arrow indicates the direction of solvent evaporation in the cationic solution). This promotes the evaporation of the solvent in the cationic solution, allowing the cations to react with the lead halide skeleton layer to form perovskite crystals. However, the perovskite layer prepared by this method contains a large amount of residual lead halide, especially at the bottom of the perovskite layer. This leads to poor crystallinity, resulting in a large number of defects in the perovskite layer, which limits further improvement in the energy conversion efficiency of perovskite tandem solar cells.

[0068] The present application provides a method for preparing a perovskite layer. During the preparation process of the perovskite layer, an inversion treatment is performed before annealing (refer to Figure 2 for the annealing method, where the direction of the arrow indicates the direction of solvent volatilization in the cationic solution). After the solvent of the cationic solution evaporates, a solvent atmosphere is formed that is conducive to the reaction between lead iodide and cations. This solvent atmosphere not only promotes the cationic reagent to penetrate into the bottom of the lead iodide skeleton layer, but also promotes the further occurrence of the reaction between lead iodide and cations, thereby promoting the formation of perovskite crystals, reducing excess lead iodide, and promoting the fusion of perovskite layer grains. The grain boundaries of the perovskite layer are reduced, and higher quality large-particle crystals are generated, thereby solving the problems of poor crystallinity and many crystal defects in the current perovskite layer.

[0069] The technical solution of the present invention will be further described below in conjunction with embodiments and drawings.

[0070] In a first aspect, an embodiment of the present application provides a method for preparing a perovskite layer 4.

[0071] The method for preparing the perovskite layer 4 comprises the following steps:

[0072] Providing a substrate having a first suede surface and a breathable heat-conductive layer respectively;

[0073] A conformal lead halide skeleton layer is prepared on the surface of a substrate, and a cationic solution is coated on the lead halide skeleton layer to obtain a perovskite intermediate structure having a second velvet surface; wherein the cationic solution includes a volatile solvent and a cationic reagent dissolved in the volatile solvent;

[0074] The perovskite intermediate structure is inverted and arranged opposite to the breathable thermal conductive layer, so that a restricted area is formed between the second suede surface and the breathable thermal conductive layer;

[0075] The inverted perovskite intermediate structure is annealed to obtain a perovskite layer 4 .

[0076] The aforementioned restricted region refers to the region formed between the second velvet surface of the inverted perovskite intermediate structure and the relative breathable thermally conductive layer. For example, by making the tip of the second velvet surface of the inverted perovskite intermediate structure abut against the breathable thermally conductive layer, or by making the tip of the second velvet surface of the inverted perovskite intermediate structure close to the breathable thermally conductive layer, a restricted region that restricts the volatilization of volatile solvent vapor can be formed between the perovskite intermediate structure and the relative breathable thermally conductive layer. During the annealing step, the volatile solvent remaining in the perovskite intermediate structure is heated to form vapor. The formation of this region has a limiting effect on the rapid volatilization of the volatile solvent vapor. Therefore, during the annealing step, the concentration of the volatile solvent vapor increases within the restricted region, forming a solvent atmosphere that is conducive to promoting the reaction between the lead halide skeleton layer and the cationic solution.

[0077] As shown in Figure 2, in the process of preparing the perovskite layer 4, a lead halide skeleton layer is first deposited on the first velvet surface of the substrate, and then a cationic solution is coated on the surface of the lead halide skeleton layer. After coating, part of the volatile solvent in the cationic solution quickly evaporates into the air, and the remaining volatile solvent enters the lead halide skeleton layer along with the cationic reagent, obtaining a perovskite intermediate structure with a relatively stable surface morphology and residual volatile solvent inside. By inverting the perovskite intermediate structure above the breathable thermal conductive layer, the tip of the second velvet surface of the perovskite intermediate structure faces the breathable thermal conductive layer, and is opposite to the breathable thermal conductive layer to form a restricted area. During the annealing process, the residual volatile solvent in the lead halide skeleton layer evaporates and enters the restricted area. The restricted area has a certain blocking effect on the volatilization of the volatile solvent vapor, resulting in a decrease in the volatilization rate of the volatile solvent vapor, which promotes the increase of the volatile solvent vapor content in the restricted area and forms a solvent atmosphere with a high solvent vapor content. After the solvent atmosphere is formed, it is conducive to promoting the penetration of cations into the bottom of the lead halide skeleton layer, and also promotes the reaction of cations with the lead halide skeleton layer to form perovskite crystals, thereby reducing the lead iodide reaction residue at the bottom of the perovskite layer 4, reducing the interface defects of the perovskite layer 4, and facilitating carrier transport and the improvement of the interface stability of the perovskite layer 4, thereby improving the energy conversion efficiency of the perovskite stacked solar cell.

[0078] In addition, under the action of the above-mentioned solvent atmosphere, the perovskite grains are fully fused, and large-grain perovskite is easily formed, thereby reducing the grain boundaries of the perovskite layer 4 and further reducing the grain boundary defects of the perovskite layer 4, thereby improving the carrier lifetime and reducing non-radiative recombination, and ultimately obtaining a perovskite tandem solar cell with higher energy conversion efficiency.

[0079] In summary, the present application adopts a simple and controllable solution to solve the problem of residual lead iodide that is easily present at the bottom of the perovskite layer 4 when the shape-retaining perovskite layer 4 is prepared by reacting a lead halide skeleton layer and a cationic solution. The perovskite layer 4 prepared by this preparation method has good shape retention on substrates of different velvet sizes and excellent repeatability, and has a large range of applications.

[0080] In some embodiments, the breathable heat-conducting layer has holes therein, and the diameter of the holes in the breathable heat-conducting layer is 0.1 μm to 10 μm.

[0081] By controlling the pore size of the breathable, thermally conductive layer, the evaporation rate of the volatile solvent vapor can be effectively adjusted. When the pore size of the breathable, thermally conductive layer is within the above range, the volatile solvent vapor escapes relatively slowly, facilitating the rapid formation of a solvent atmosphere within the restricted area that is conducive to the reaction between the lead halide skeleton layer and the cationic solution.

[0082] In some embodiments, the breathable heat-conductive layer is one or more of filter paper, glass sheet, polymer film, porous metal material and porous ceramic material.

[0083] The inverted perovskite mesostructure is annealed on a heating device. A breathable thermally conductive layer is placed on the heating device, which can be a hot plate. Upon activation, heat is transferred from the heating device through the breathable thermally conductive layer to the perovskite mesostructure. The breathable thermally conductive layer is preferably filter paper, which has good thermal conductivity and high thermal conductivity, facilitating heat transfer. The temperature of the perovskite mesostructure increases, prompting the evaporation of the solvent in the cation solution, creating a localized solvent atmosphere that facilitates the reaction between the lead halide skeleton layer and the cations.

[0084] In some embodiments, the first texture surface has a size of 1 μm to 6 μm.

[0085] The higher the first velvet surface of the substrate, the more obvious the residual lead iodide at the bottom of the conformal perovskite layer 4 prepared by reacting the lead halide skeleton layer and the cationic solution. For the conformal perovskite layer 4 prepared on substrates of the above-mentioned velvet surface size, the present application scheme is excellent in reducing the residual lead iodide in the perovskite layer 4, and can achieve the preparation of a perovskite layer 4 with low residual lead iodide on pyramid velvet substrates of various heights.

[0086] In some embodiments, the annealing treatment is performed at a temperature of 120° C. to 170° C. for 20 min to 30 min.

[0087] Under the above annealing conditions, the residual volatile solvent in the lead halide skeleton layer is converted into a volatile solvent vapor state, which is conducive to forming a solvent atmosphere with a high solvent vapor content in the restricted area, promoting the reaction of lead iodide at the bottom of the lead halide skeleton layer, reducing the residual lead iodide at the bottom, and at the same time promoting the formation of large-grained perovskite crystals. The final perovskite layer 4 has less lead iodide residue and larger perovskite crystal particles.

[0088] In some embodiments, the volatile solvent includes one or both of ethanol and isopropanol.

[0089] Ethanol and isopropanol have low boiling points and good volatility. When the cationic solution is applied to the lead halide skeleton layer, part of the ethanol and / or isopropanol can evaporate quickly, so that the surface of the perovskite structure intermediate forms a relatively stable morphology. Ethanol and / or isopropanol have good permeability in the lead halide skeleton layer. After the perovskite intermediate structure is inverted, it is conducive to forming a better solvent atmosphere in the confined area between the perovskite intermediate structure and the breathable thermal conductive layer, thereby better promoting the reaction between the lead halide skeleton layer and the cation, reducing the excess lead iodide, and promoting the improvement of the crystallization quality and stability of the perovskite layer 4.

[0090] Preferably, the volatile solvent is composed of ethanol and isopropanol in a mass ratio of 1: (0.5-2). Combining ethanol and isopropanol in the above mass ratio is more conducive to the formation of a stable surface morphology of the perovskite structure intermediate. At the same time, the solvent combination better promotes the reaction between the lead halide skeleton layer and the cation, further reduces the excess lead iodide, reduces the defects of the perovskite layer 4, and thus better transports carriers, thereby improving the fill factor and open circuit voltage of the perovskite tandem solar cell.

[0091] In some embodiments, the cation of the cationic reagent comprises one or more of methylammonium, formamidine and cesium ions, and the anion of the cationic reagent comprises one or more of chloride, bromide and iodide; and / or,

[0092] The lead halide skeleton layer includes at least lead iodide.

[0093] The cationic solution is composed of AX, where the A position is usually a positive monovalent organic cation, such as methylammonium, formamidine and cesium ion, and the X position is a negative monovalent halogen ion, such as chloride, bromide and iodide. The lead halide skeleton layer includes at least lead iodide, and further, the lead halide skeleton layer also includes cesium bromide. By regulating the components of the above-mentioned cationic solution and the components and proportions of each element of the lead halide skeleton layer, it can be adjusted according to the band gap requirements of the perovskite layer 4. The specific composition of the lead halide skeleton layer and the cationic solution is not limited in the embodiment of the present application.

[0094] In some embodiments, the lead halide skeleton layer is prepared by evaporation.

[0095] The lead halide skeleton layer prepared by evaporation has excellent shape retention, relatively high density, and high structural stability. This is very beneficial for preparing the perovskite layer 4 with excellent shape retention on the first velvet surface. It also facilitates the formation of a perovskite intermediate structure with a stable surface morphology, making it less susceptible to damage when inverted and maintaining a stable surface morphology. The perovskite intermediate structure formed by coating the lead halide skeleton layer with a cationic solution also has high stability and is less susceptible to damage and deformation when inverted. Therefore, after inversion, the perovskite intermediate structure can form a stable confined area with the breathable and thermally conductive layer.

[0096] In some embodiments, the thickness of the lead halide skeleton layer is 300 nm to 400 nm, and the thickness of the perovskite layer 4 is 450 nm to 550 nm.

[0097] The perovskite layer 4 of the above-mentioned thickness has a better light absorption effect, and the thickness between the lead iodide thickness and the perovskite layer 4 is reasonably designed. The present application effectively solves the problem of lead iodide residue that is easily generated when the perovskite layer 4 of this thickness is prepared on the first velvet surface. Therefore, a 450nm to 550nm perovskite layer 4 is prepared through a 300nm to 400nm lead halide skeleton layer. The perovskite layer 4 has less lead iodide residue, and the electron transfer efficiency and photoelectric conversion efficiency of the perovskite stacked solar cell prepared by the perovskite layer 4 are improved.

[0098] In a second aspect, an embodiment of the present application provides a perovskite tandem solar cell.

[0099] The perovskite tandem solar cell comprises:

[0100] Texturing silicon substrate battery 1;

[0101] A first transparent conductive layer 2 stacked on the front surface of the silicon substrate cell;

[0102] A hole transport layer 3 stacked on the first transparent conductive layer 2 on a side away from the textured silicon substrate cell 1;

[0103] A perovskite layer 4 stacked on the hole transport layer 3 on the side away from the textured silicon substrate cell 1, wherein the perovskite is prepared by the preparation method of the perovskite layer 4 of the first aspect;

[0104] An electron transport layer 5 stacked on the side of the perovskite layer 4 facing away from the textured silicon substrate cell 1;

[0105] A second transparent conductive layer 7 stacked on the electron transport layer 5 on a side away from the textured silicon substrate cell 1;

[0106] The first electrode 8 and the second electrode 9 are further included. The second electrode 9 forms an ohmic contact with the second transparent conductive layer 7, and the first electrode 8 forms an ohmic contact with the silicon substrate battery.

[0107] The perovskite layer 4 prepared by the above method has better crystallization properties and fewer defects, which is conducive to the transmission of carriers and improves the stability of the perovskite layer 4, thereby improving the stability and photoelectric conversion efficiency of the perovskite tandem solar cell.

[0108] In some embodiments, the thickness of the first transparent conductive layer 2 is 80nm to 100nm; and / or the thickness of the hole transport layer 3 is 20nm to 30nm; and / or the thickness of the electron transport layer 5 is 15nm to 25nm; and / or the thickness of the second transparent conductive layer 7 is 80nm to 130nm; and / or the thickness of the first electrode 8 is 300nm to 350nm; and / or the thickness of the second electrode 9 is 300nm to 350nm.

[0109] In some embodiments, the material of the first transparent conductive layer 2 is indium zinc oxide or indium tin oxide; and / or the material of the hole transport layer 3 is nickel oxide; and / or the material of the electron transport layer 5 is C 60 ; and / or, the material of the second transparent conductive layer 7 is indium zinc oxide or indium tin oxide; and / or, the material of the first electrode 8 is silver; and / or, the material of the second electrode 9 is silver.

[0110] In some embodiments, referring to FIG. 3 , a buffer layer 6 is provided between the electron transport layer 5 and the second transparent conductive layer 7 , and the thickness of the buffer layer 6 is 20 nm to 30 nm.

[0111] In a third aspect, the present application provides a method for preparing a perovskite tandem solar cell.

[0112] The preparation method of the perovskite tandem solar cell comprises the following steps:

[0113] Providing a textured silicon substrate cell 1;

[0114] Prepare a first transparent conductive layer 2 on the front side of the textured silicon substrate battery 1;

[0115] A hole transport layer 3 is formed on the first transparent conductive layer 2;

[0116] A perovskite layer 4 is prepared on the hole transport layer 3, wherein the perovskite layer 4 is the perovskite layer 4 mentioned in the first aspect;

[0117] An electron transport layer 5 is formed on the perovskite layer 4;

[0118] forming a second transparent conductive layer 7 on the electron transport layer 5;

[0119] A second electrode 9 is formed on the second transparent conductive layer 7 , and a first electrode 8 is formed on the back side of the textured silicon substrate battery 1 .

[0120] In some embodiments, the first transparent conductive layer 2 is prepared by physical vapor deposition, the hole transport layer 3 is prepared by physical vapor deposition, the electron transport layer 5 is prepared by evaporation, and the second transparent conductive layer 7 is prepared by physical vapor deposition.

[0121] The technical solution of the present invention will be further described below in conjunction with more specific embodiments and drawings.

[0122] Example 1

[0123] A perovskite tandem solar cell, comprising:

[0124] Heterojunction bottom cell, the heterojunction bottom cell has a pyramid velvet surface, and the size of the pyramid velvet surface is 1μm;

[0125] The first transparent conductive layer 2 stacked on the front of the heterojunction bottom cell, the first electrode layer material is indium tin oxide, and the thickness is 90nm;

[0126] A hole transport layer 3 is stacked on the side of the first transparent conductive layer 2 facing away from the heterojunction bottom cell. The hole transport layer 3 is made of nickel oxide and has a thickness of 25 nm.

[0127] The perovskite layer 4 stacked on the side of the hole transport layer 3 facing away from the heterojunction bottom cell has a thickness of 500 nm;

[0128] The electron transport layer 5 is stacked on the side of the perovskite layer 4 away from the heterojunction bottom cell. The electron transport layer 5 material is C 60 , thickness is 20nm;

[0129] A buffer layer 6 is stacked on the side of the electron transport layer 5 away from the heterojunction bottom cell. The buffer layer 6 is made of tin dioxide and has a thickness of 25 nm.

[0130] A second transparent conductive layer 7 is stacked on the side of the buffer layer 6 facing away from the heterojunction bottom cell. The second transparent conductive layer 7 is made of indium zinc oxide and has a thickness of 115 nm.

[0131] All the above film layers grow conformally along the pyramidal velvet surface of the heterojunction bottom cell;

[0132] It also includes a first electrode 8 and a second electrode 9. The first electrode 8 and the second electrode 9 are both silver electrodes. The thickness of the first electrode 8 and the second electrode 9 are 275 nm respectively. The second electrode 9 forms an ohmic contact with the second transparent conductive layer 7, and the first electrode 8 forms an ohmic contact with the back side of the heterojunction bottom battery.

[0133] The preparation method of the above-mentioned perovskite tandem solar cell is as follows:

[0134] Provide heterojunction bottom cells with a pyramid velvet structure;

[0135] The hole transport layer 3 is prepared on the front side of the heterojunction bottom cell by physical vapor deposition;

[0136] The perovskite layer 4 is prepared on the hole transport layer 3. The specific method is as follows:

[0137] The hole transport layer 3 having the first textured surface is used as a substrate for preparing the perovskite layer 4;

[0138] A conformal lead halide skeleton layer with a thickness of 350 nm is prepared along the surface of the substrate by evaporation, and a cationic solution is coated on the lead halide skeleton layer. The cationic solution is a mixed solution of methyl bromide, iodoformamidine, and cesium chloride. The solvent is anhydrous ethanol. The concentration of methyl bromide is 0.15 mol / L, the concentration of iodoformamidine is 0.45 mol / L, and the concentration of cesium chloride is 0.1 mol / L, thereby obtaining a perovskite intermediate structure with a second textured surface.

[0139] Place filter paper on a hot plate, and invert the perovskite intermediate structure onto the filter paper so that the tip of the second velvet surface of the perovskite intermediate structure abuts against the breathable heat-conductive layer. Then, increase the temperature of the hot plate and anneal at 130° C. for 25 minutes to obtain a perovskite layer 4.

[0140] An electron transport layer 5 is prepared on the perovskite layer 4 by evaporation;

[0141] A buffer layer 6 is prepared on the electron transport layer 5 by atomic layer deposition;

[0142] A second transparent conductive layer 7 is formed on the buffer layer 6 by using a physical vapor deposition method;

[0143] The second electrode 9 is prepared on the second transparent conductive layer 7 by using the evaporation method, and the first electrode 8 is prepared on the back of the heterojunction bottom cell by using the evaporation method to obtain a perovskite tandem solar cell.

[0144] Example 2

[0145] The embodiment of the present application provides a perovskite tandem solar cell, which differs from the first embodiment in that the size of the pyramid velvet surface on the surface of the heterojunction bottom cell is 3 μm.

[0146] Example 3

[0147] The embodiment of the present application provides a perovskite tandem solar cell, which differs from the first embodiment in that the size of the pyramid velvet surface on the surface of the heterojunction bottom cell is 6 μm.

[0148] Example 4

[0149] The embodiment of the present application provides a perovskite tandem solar cell, which differs from the first embodiment in that the solvent of the cationic solution is composed of ethanol and isopropanol in a mass ratio of 1:1.

[0150] Comparative Example 1

[0151] The comparative example of the present application provides a perovskite tandem solar cell, which differs from the first embodiment in that the preparation method of the perovskite layer 4 is as follows:

[0152] The hole transport layer 3 having the first suede surface is used as a substrate;

[0153] A conformal lead halide skeleton layer with a thickness of 350 nm is prepared along the surface of the substrate by evaporation, and a cationic solution is coated on the lead halide skeleton layer. The cationic solution is a mixed solution of methyl bromide, iodoformamidine, and cesium chloride. The solvent is anhydrous ethanol. The concentration of methyl bromide is 0.15 mol / L, the concentration of iodoformamidine is 0.45 mol / L, and the concentration of cesium chloride is 0.1 mol / L, thereby obtaining a perovskite intermediate structure with a second textured surface.

[0154] The above-mentioned perovskite intermediate structure was placed upright on a hot plate with the tip of the second velvet surface of the perovskite intermediate structure facing upwards. The heating plate was then heated and annealed at 130°C for 25 minutes to obtain a perovskite layer 4. Experiment 1

[0155] SEM electron microscope scanning was performed on the perovskite layers prepared in Example 1, Example 3 and Comparative Example 1, respectively, and the morphology images of the perovskite layer prepared in Example 1 were obtained as Figures 4 and 5, the morphology image of the perovskite layer prepared in Example 3 was obtained as Figure 6, and the morphology image of the perovskite layer prepared in Comparative Example 1 was obtained as Figure 7.

[0156] The bottom of the valley of the pyramid-structured perovskite layer in Figure 7 has a large number of bright white spots, which are residual lead iodide from the reaction. The number of bright white spots in the valley of the pyramid-structured perovskite layer in Figures 4 and 6 is significantly reduced, which proves that inverting the perovskite intermediate structure on the breathable thermal conductive layer to form a restricted area between the perovskite intermediate structure and the breathable thermal conductive layer, and then performing annealing treatment, is more conducive to promoting the reaction of the lead halide skeleton layer with the cationic solution, thereby reducing the residual lead iodide and improving the carrier transport effect and stability of the perovskite layer.

[0157] Figure 5 is a SEM image of the surface morphology of Example 1. It can be seen from Figure 5 that after the perovskite intermediate structure is inverted and annealed, the surface morphology of the obtained perovskite layer is intact, and the inversion treatment does not damage the surface morphology of the perovskite layer. It can be seen from the surface morphology of the perovskite layer that the crystallization effect of the perovskite is excellent.

[0158] Experiment 2

[0159] The performance tests of open circuit voltage, short circuit current density, fill factor and energy conversion efficiency were carried out using Halm test and sorting equipment. Halm is a device that simulates sunlight and is equipped with electronic load, data acquisition and calculation equipment to test the electrical performance of the perovskite silicon tandem solar cells in the above embodiments and comparative examples. The silicon wafer of the solar cell used in the control test was 1.07 cm 2 , the calibration light intensity is 1000±50W / m 2 The experimental test results are as follows, where PCE represents the energy conversion efficiency (%), Voc represents the open circuit voltage (V), and Jsc represents the short circuit current density (mA / cm 2 , FF represents the fill factor. The test results are shown in Table 1.

[0160] Table 1

[0161] It can be seen from the experimental results in Table 1 that the energy conversion efficiency of Example 1, Example 2, Example 3 and Example 4 is relatively high, which proves that the perovskite tandem solar cells prepared in the above examples have fewer defects, excellent carrier transport effects and better electrical properties.

[0162] Compared with comparative example 1, the open circuit voltage of embodiment 1 is increased by 0.034V and the short circuit current is reduced by 0.04mA / cm 2 , the filling factor is increased by 0.02, and the energy conversion efficiency is increased by 1.11%, which proves that after the inversion treatment, the interface reaction of the perovskite layer is good, the lead iodide residue is reduced, the crystallization quality is improved, and the interface defects are less. Therefore, the open circuit voltage and filling factor of Example 1 are improved, and finally the energy conversion efficiency of Example 1 is further improved.

[0163] By comparing Example 1, Example 2, and Example 3, it can be seen that in the preparation process of perovskite layers with different pyramid heights, the use of inverted confinement annealing can effectively reduce the defects of the perovskite layer. As the pyramid height increases, the effect of inverted confinement annealing on reducing lead iodide excess and reducing interface defects in the perovskite layer is improved.

[0164] Compared with Example 1, the open circuit voltage of Example 4 is increased by 0.029 V and the short circuit current is reduced by 0.04 mA / cm 2 , the filling factor is increased by 0.07, and the energy conversion efficiency is increased by 2.8%, which proves that the solvent atmosphere formed in the confined area by using ethanol and isopropanol in a mass ratio of 1:1 as solvents is better for promoting the reaction between the cationic solution and the lead halide skeleton layer. The resulting perovskite layer has less residual lead iodide, better crystallization quality of the perovskite layer, and fewer interface defects, which further improves the open circuit voltage and filling factor of Example 4.

[0165] The above is a detailed introduction to the preparation method of the perovskite layer, the perovskite tandem solar cell and the preparation method thereof disclosed in the embodiments of the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the preparation method of the perovskite layer, the perovskite tandem solar cell and the preparation method thereof and their core ideas of the present invention: At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for preparing a perovskite layer, characterized in that: The method for preparing the perovskite layer comprises the following steps: Provide a substrate having a first suede surface and a breathable heat-conductive layer respectively; A conformal lead halide skeleton layer is prepared on the surface of the substrate, and a cationic solution is coated on the lead halide skeleton layer to obtain a perovskite intermediate structure having a second velvet surface; wherein the cationic solution comprises a volatile solvent and a cationic agent dissolved in the volatile solvent; Inverting the perovskite intermediate structure and arranging it opposite to the breathable heat-conducting layer, so that a restricted area is formed between the second velvet surface and the breathable heat-conducting layer; The inverted perovskite intermediate structure is annealed to obtain the perovskite layer.

2. The method for preparing a perovskite layer according to claim 1, characterized in that: The restricted area is an area formed between the second velvet surface of the inverted perovskite intermediate structure and the opposite breathable heat-conductive layer, and the tip of the second velvet surface of the inverted perovskite intermediate structure is close to or abuts against the breathable heat-conductive layer.

3. The method for preparing a perovskite layer according to any one of claims 1 to 2, characterized in that: The air-permeable heat-conducting layer has holes therein, and the diameter of the holes in the air-permeable heat-conducting layer is 0.1 μm to 10 μm.

4. The method for preparing a perovskite layer according to any one of claims 1 to 3, characterized in that: The air-permeable heat-conducting layer includes one or more of filter paper, glass sheet, polymer film, porous metal material and porous ceramic material.

5. The method for preparing a perovskite layer according to any one of claims 1 to 4, characterized in that: The first velvet surface is a pyramid velvet surface, wherein the size of the pyramid structure is 1 μm to 6 μm.

6. The method for preparing a perovskite layer according to any one of claims 1 to 5, characterized in that: The annealing treatment is performed at a temperature of 120° C. to 170° C. and for a time of 20 min to 30 min.

7. The method for preparing a perovskite layer according to any one of claims 1 to 6, characterized in that: The volatile solvent includes one or both of ethanol and isopropanol.

8. The method for preparing a perovskite layer according to claim 7, characterized in that: The volatile solvent includes the ethanol and the isopropanol, and the mass ratio of the ethanol to the isopropanol is 1:(0.5-2).

9. The method for preparing a perovskite layer according to claim 8, characterized in that: The volatile solvent consists of the ethanol and the isopropanol.

10. The method for preparing a perovskite layer according to any one of claims 1 to 9, characterized in that: The cations in the cationic reagent include one or more of methylammonium, formamidine and cesium ions, and the anions in the cationic reagent include one or more of chloride ions, bromide ions and iodide ions.

11. The method for preparing a perovskite layer according to any one of claims 1 to 10, characterized in that: The lead halide skeleton layer at least includes lead iodide.

12. The method for preparing a perovskite layer according to any one of claims 1 to 11, characterized in that: The lead halide skeleton layer is prepared by evaporation method.

13. The method for preparing a perovskite layer according to any one of claims 1 to 12, characterized in that: The thickness of the lead halide skeleton layer is 300nm-400nm, and the thickness of the perovskite layer is 450nm-550nm.

14. A perovskite tandem solar cell, characterized in that: The perovskite tandem solar cell comprises a perovskite layer, and the perovskite layer is prepared by the method for preparing a perovskite layer according to any one of claims 1 to 13.

15. The perovskite tandem solar cell according to claim 14, characterized in that: The perovskite tandem solar cell comprises: Texturing silicon substrate battery; A first transparent conductive layer stacked on the front side of the silicon substrate cell; A hole transport layer stacked on the first transparent conductive layer on a side away from the texturing silicon substrate cell; The perovskite layer is stacked on the side of the hole transport layer away from the texturing silicon substrate cell; An electron transport layer stacked on the side of the perovskite layer away from the texturing silicon substrate cell; A second transparent conductive layer stacked on the electron transport layer at a side away from the texturing silicon substrate cell; A first electrode and a second electrode, wherein the second electrode forms an ohmic contact with the second transparent conductive layer, and the first electrode forms an ohmic contact with the silicon substrate cell.

16. The perovskite tandem solar cell according to claim 15, characterized in that: The thickness of the first transparent conductive layer is 80 nm to 100 nm.

17. The perovskite tandem solar cell according to any one of claims 15 to 16, characterized in that: The thickness of the hole transport layer is 20 nm to 30 nm.

18. The perovskite tandem solar cell according to any one of claims 15 to 17, characterized in that: The thickness of the electron transport layer is 15 nm to 25 nm.

19. The perovskite tandem solar cell according to any one of claims 15 to 18, characterized in that: The thickness of the second transparent conductive layer is 80 nm to 130 nm.

20. The perovskite tandem solar cell according to any one of claims 15 to 19, characterized in that: The thickness of the first electrode is 300 nm to 350 nm.

21. The perovskite tandem solar cell according to any one of claims 15 to 20, characterized in that: The thickness of the second electrode is 300 nm to 350 nm.

22. The perovskite tandem solar cell according to any one of claims 15 to 21, characterized in that: The material of the first transparent conductive layer is indium zinc oxide or indium tin oxide.

23. The perovskite tandem solar cell according to any one of claims 15 to 22, characterized in that: The material of the hole transport layer is nickel oxide.

24. The perovskite tandem solar cell according to any one of claims 15 to 23, characterized in that: The material of the electron transport layer is C 60 .

25. The perovskite tandem solar cell according to any one of claims 15 to 24, characterized in that: The material of the second transparent conductive layer is indium zinc oxide or indium tin oxide.

26. The perovskite tandem solar cell according to any one of claims 15 to 25, characterized in that: The material of the first electrode is silver.

27. The perovskite tandem solar cell according to any one of claims 15 to 26, characterized in that: The material of the second electrode is silver.

28. The perovskite tandem solar cell according to any one of claims 15 to 27, characterized in that: A buffer layer is disposed between the electron transport layer and the second transparent conductive layer, and the thickness of the buffer layer is 20 nm to 30 nm.

29. A method for preparing a perovskite tandem solar cell, characterized in that: The method for preparing the perovskite tandem solar cell comprises: preparing the perovskite layer by adopting the method for preparing the perovskite layer according to any one of claims 1 to 13.

30. The method for preparing a perovskite tandem solar cell according to claim 29, characterized in that: The preparation method comprises the following steps: Provide silicon substrate cells; Prepare a first transparent conductive layer on the front side of the silicon substrate battery; preparing a hole transport layer on the first transparent conductive layer; The perovskite layer is prepared by the method for preparing a perovskite layer according to any one of claims 1 to 13; preparing an electron transport layer on the perovskite layer; preparing a second transparent conductive layer on the electron transport layer; A second electrode is prepared on the second transparent conductive layer, and a first electrode is prepared on the back side of the silicon substrate battery.

31. The method for preparing a perovskite tandem solar cell according to claim 30, characterized in that: The first transparent conductive layer is prepared by physical vapor deposition, the hole transport layer is prepared by physical vapor deposition, the electron transport layer is prepared by evaporation, and the second transparent conductive layer is prepared by physical vapor deposition.

32. The method for preparing a perovskite tandem solar cell according to any one of claims 30 to 31, characterized in that: The silicon substrate cell is a texturing silicon substrate cell.

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