A perovskite thin film, a perovskite cell, a four-terminal stacked cell, a four-terminal stacked assembly and a method for manufacturing the same

Abstract

This invention belongs to the photovoltaic field, specifically relating to a perovskite thin film, a perovskite solar cell, a four-terminal tandem solar cell, a four-terminal tandem module, and their preparation methods. The perovskite thin film of this invention has uniformly distributed pores; the pores are coffee-ring shaped and penetrate the perovskite thin film; the area of ​​a single pore is 0.5 μm². 2 -10mm 2 The distribution density of the pores is 1-100 pores / cm². 2 The term "uniform distribution" refers to the fact that the area range of individual pores in any two randomly selected regions of the perovskite film with the same area is the same, and the distribution density error of the pores in the two randomly selected regions with the same area is less than 10%, wherein the area of ​​the two randomly selected regions with the same area is ≥100 cm². 2 The uniformly distributed micropores on the surface of the perovskite thin film of this invention change the appearance standard of the product and help improve the yield of perovskite / crystalline silicon four-terminal stacked modules.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaics, specifically relating to a perovskite thin film, a perovskite cell, a four-terminal stacked cell, a four-terminal stacked module, and a method for preparing the same. Background Technology

[0002] Solar energy, as a clean and renewable energy source, has received widespread attention from academia and industry. Perovskite materials, with their excellent photoelectric properties and low cost, are used as the light-absorbing layer in solar cells, forming perovskite solar cells (PSCs) that possess excellent photoelectric performance (the highest certified efficiency of single-junction perovskite solar cells has reached 26.88%), low cost, and simple processing. Perovskite solar cells have attracted considerable attention in the third generation of solar cells.

[0003] Furthermore, perovskite materials, due to their tunable bandgap, can be stacked with other photovoltaic materials with different bandgapes to form tandem solar cells, effectively improving photoelectric conversion efficiency. Depending on the connection method of the top and bottom cells, tandem solar cells are mainly divided into two-terminal and four-terminal tandem cells. For mechanically stacked four-terminal tandem cells, in addition to improving the efficiency of the top and bottom cells, the optical distribution of the top and bottom cells is also crucial to improving device efficiency. Therefore, how to rationally control the optical distribution of the four-terminal tandem cells to achieve optimal optical distribution is essential for improving the performance of four-terminal tandem solar cells.

[0004] Current research on optical distribution in four-terminal stacked perovskites primarily focuses on adjusting the bandgap of the perovskite material. However, while narrow-bandgap perovskite materials possess superior photoelectric conversion efficiency, their absorption spectra are quite similar to those of crystalline silicon bottom cells, resulting in less incident light and limiting the overall efficiency improvement of four-terminal stacked cells. Wide-bandgap perovskite materials, on the other hand, have absorption spectra biased towards shorter wavelengths, allowing more long-wavelength light to enter the crystalline silicon bottom cell, achieving better optical distribution. However, wide-bandgap perovskites themselves suffer from severe phase separation and difficult crystallization control, hindering the efficiency and stability improvement of perovskite top cells. Furthermore, four-terminal stacked modules require the fabrication of perovskite top cells over a large area, and a series of defects during the fabrication process of large-area perovskite films (thickness uniformity, crystallization uniformity, porosity, etc.) simultaneously restrict the cell quality of perovskite top cells.

[0005] Therefore, there is an urgent need to develop a perovskite thin film to improve the yield of four-terminal stacked modules. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a perovskite thin film, a perovskite solar cell, a four-terminal stacked solar cell, a four-terminal stacked module, and a method for preparing the same. The uniformly distributed micropores on the surface of the perovskite thin film of this invention alter the product's appearance standards and are beneficial for improving product yield.

[0007] Specifically, the present invention provides a perovskite thin film having uniformly distributed pores, the pores being in the shape of coffee rings and penetrating the perovskite thin film; the area of ​​a single pore is 0.5 μm. 2 -10mm 2 The distribution density of the pores is 1-100 pores / cm². 2 The term "uniform distribution" refers to the fact that the area range of individual pores in any two randomly selected regions of the perovskite film with the same area is the same, and the distribution density error of the pores in the two randomly selected regions with the same area is less than 10%, wherein the area of ​​the two randomly selected regions with the same area is ≥100 cm². 2 .

[0008] In one or more embodiments, the perovskite film comprises a perovskite structural material and nanoparticles.

[0009] In one or more embodiments, the nanoparticles include one or both of nickel oxide nanoparticles and aluminum oxide nanoparticles.

[0010] In one or more embodiments, the nanoparticles are nickel oxide nanoparticles.

[0011] In one or more embodiments, the nanoparticles have a particle size of 20-500 nm.

[0012] In one or more embodiments, the nanoparticles have a particle size of 20-200 nm.

[0013] In one or more embodiments, the nanoparticle is located at the center of the coffee ring; the center location refers to a distance ≤ L / 2 between the center point of the nanoparticle and the center point of the coffee ring; L is the longest distance from the center point of the coffee ring to the edge of the coffee ring.

[0014] In one or more embodiments, the area of ​​the individual hole is 0.5 μm. 2 -1000μm 2 .

[0015] In one or more embodiments, the area of ​​the individual hole is 0.5 μm. 2 -500μm 2 .

[0016] In one or more embodiments, the area of ​​the individual hole is 0.5 μm. 2 -200μm 2 .

[0017] This invention provides a method for preparing any of the perovskite thin films described in this invention. The method includes coating a substrate precursor solution and then performing a first annealing to obtain a substrate; coating a perovskite precursor solution on the surface of the substrate and then performing a second annealing to obtain a perovskite thin film; wherein the substrate precursor solution contains nanoparticles or the perovskite precursor contains nanoparticles.

[0018] In one or more embodiments, when the substrate precursor solution contains the nanoparticles, the concentration of the nanoparticles is 0.1-8 mg / mL.

[0019] In one or more embodiments, when the perovskite precursor solution contains the nanoparticles, the concentration of the nanoparticles is 0.1-8 mg / mL.

[0020] In one or more embodiments, the substrate includes a carrier transport layer, which is a hole transport layer or an electron transport layer.

[0021] In one or more embodiments, the substrate is a hole transport layer, the substrate precursor liquid is a hole transport layer precursor liquid, and the hole transport layer precursor liquid further comprises a hole transport layer material and a solvent.

[0022] In one or more embodiments, the perovskite precursor solution further comprises perovskite structural material raw materials and solvents.

[0023] In one or more embodiments, the solvent in the hole transport layer precursor solution is an alcohol solvent.

[0024] In one or more embodiments, the concentration of the hole transport layer material in the hole transport layer precursor solution is 0.5-1.5 mg / mL.

[0025] In one or more embodiments, the perovskite precursor solution contains a first perovskite material and a second perovskite material; the first perovskite material has the chemical formula AX, and the second perovskite material has the chemical formula BX2; A is selected from one or more of methylamine ions, formamidinium ions, acetamidine ions, cesium ions, and rubidium ions; B is selected from one or more of lead ions, tin ions, copper ions, and germanium ions; X is selected from F - I - ,Br - Cl - BF4 - PF6 - and SCN - One or more of them.

[0026] In one or more embodiments, the solvent in the perovskite precursor solution is selected from one or more of dimethyl sulfoxide, N,N-dimethylformamide, acetonitrile, dimethylpyrrolidone, 2-methoxyethanol, and γ-butyrolactone.

[0027] In one or more embodiments, the concentration of the perovskite structural material raw material in the perovskite precursor solution is 0.5-1.5 mol / L.

[0028] In one or more embodiments, the substrate precursor liquid is applied by spin coating, blade coating, slot coating, or spraying.

[0029] In one or more embodiments, the perovskite precursor solution is applied by spin coating, blade coating, slot coating, or spray coating.

[0030] In one or more embodiments, the temperature of the first annealing is 100-120°C.

[0031] In one or more embodiments, the second annealing time is 2-10 minutes.

[0032] In one or more embodiments, the temperature of the first annealing is 130-150°C.

[0033] In one or more embodiments, the second annealing time is 15-30 minutes.

[0034] The present invention provides a perovskite solar cell comprising any of the perovskite thin films described in the present invention or any perovskite thin films prepared by any of the methods of the present invention.

[0035] The present invention provides a four-terminal stacked battery, the four-terminal stacked battery comprising a top battery and a bottom battery, the top battery comprising any of the perovskite batteries described in the present invention, and the bottom battery comprising a crystalline silicon battery.

[0036] The present invention provides a four-terminal stacked assembly comprising any four-terminal stacked battery of the present invention.

[0037] In one or more embodiments, the ratio of incident light penetrating the perovskite solar cell to the crystalline silicon solar cell across the entire wavelength range is 1%-10%.

[0038] In one or more embodiments, the perovskite solar cell comprises perovskite solar cells connected in series or in parallel.

[0039] In one or more embodiments, the crystalline silicon cell comprises crystalline silicon cells connected in series.

[0040] In one or more embodiments, the connection between the perovskite solar cell and the crystalline silicon solar cell is in series, parallel, or independent of each other. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the structure of an inverted perovskite solar cell prepared according to some embodiments of the present invention. Figure 1 In the diagram, 1 is the glass substrate, 2 is the front electrode layer, 3 is the hole transport layer, 4 is the perovskite thin film, 5 is the electron transport layer, 6 is the transparent electrode layer, 7 is the P1 scribe line, 8 is the P2 scribe line, 9 is the P3 scribe line, and 10 is the lead wire.

[0042] Figure 2 This is a schematic diagram of the structure of a perovskite / crystalline silicon four-terminal stacked module prepared according to some embodiments of the present invention. Figure 2 In the diagram, 21 is the perovskite top cell, 22 is the first encapsulation layer, 23 is the crystalline silicon bottom cell, 24 is the second encapsulation layer, 25 is the backsheet, and 26 is the edge water-blocking layer.

[0043] Figure 3 This is a photoluminescence mapping (PL mapping) test image of the perovskite thin film prepared in Example 1 of the present invention. Figure 4 This is a photoluminescence mapping (PL mapping) test image of the perovskite thin film prepared in Example 2 of the present invention. Figure 5 This is a photoluminescence mapping (PL mapping) test image of the perovskite thin film prepared in Example 3 of the present invention. Figure 6 This is a photoluminescence mapping (PL mapping) test image of the perovskite thin film prepared in Example 4 of the present invention. Figure 7 This is a photoluminescence mapping (PL mapping) test image of the perovskite thin film prepared in Example 5 of the present invention. Figure 8 This is a photoluminescence mapping (PL mapping) test image of the perovskite thin film prepared in Example 6 of the present invention. Figure 9 This is a photoluminescence mapping (PL mapping) test image of the perovskite thin film prepared in Example 7 of the present invention. Figure 10 This is a photoluminescence mapping (PLMapping) test image of the perovskite thin film prepared in Comparative Example 1 of this invention. Figure 11 This is a photoluminescence mapping (PL mapping) test image of the perovskite thin film prepared in Comparative Example 2 of this invention. Detailed Implementation

[0044] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0045] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0046] In this document, the terms “contains,” “includes,” “containing,” and similar terms encompass the meanings of “basically composed of” and “composed of.” For example, when this document discloses “A contains B and C,” “A is basically composed of B and C” and “A is composed of B and C” should be considered as having been disclosed in this document.

[0047] In this document, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0048] Unless otherwise specified, percentages refer to mass percentages and proportions refer to mass ratios in this article.

[0049] In this document, when describing embodiments or examples, it should be understood that it is not intended to limit the invention to those embodiments or examples. Rather, all alternatives, modifications, and equivalents of the methods and materials described herein are covered within the scope defined by the claims.

[0050] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0051] This invention provides a perovskite thin film with uniformly distributed pores; the pores are coffee-ring shaped and penetrate the entire perovskite thin film; the area of ​​a single pore can be 0.5 μm. 2 -10mm 2 For example, 0.5μm 2 -2000μm 2 0.5μm 2 -1000μm 2 0.5μm 2 -500μm 2 0.5μm 2 -200μm 2 The density of pores can range from 1 to 100 pores / cm². 2 For example, 10 per cm 2 20 pieces / cm 2 30 pieces / cm2 40 pieces / cm 2 50 pieces / cm 2 60 pieces / cm 2 70 pieces / cm 2 80 pieces / cm 2 90 pieces / cm 2 100 pieces / cm 2 In this invention, uniform distribution refers to the fact that the area range of individual pores in any two randomly selected regions of the perovskite thin film with the same area is the same, and the distribution density error of the pores in the two randomly selected regions with the same area is less than 10%, wherein the area of ​​the two randomly selected regions with the same area is ≥100 cm². 2 The uniformly distributed micropores on the surface of the perovskite thin film of this invention change the appearance standard of the product and help improve the product yield.

[0052] In this invention, the perovskite thin film may comprise perovskite structural material and nanoparticles. The thickness of the perovskite thin film may be 300-800 nm, for example, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, or 800 nm.

[0053] In this invention, the nanoparticles are located at the center of the coffee ring; the center position means that the distance between the center point of the nanoparticles and the center point of the coffee ring is ≤L / 2; L is the longest distance from the center point of the coffee ring to the edge of the coffee ring.

[0054] In this invention, the chemical formula of the perovskite structure is ABX3, where A can be one or more selected from methylamine ions, formamidinium ions, acetamidine ions, cesium ions, and rubidium ions; B can be one or more selected from lead ions, tin ions, copper ions, and germanium ions; and X can be selected from F... - I - ,Br - Cl - BF4 - PF6 - and SCN - One or more of them.

[0055] In this invention, the nanoparticles can be nickel oxide nanoparticles (NiOx) and / or aluminum oxide (AlOx) nanoparticles, preferably nickel oxide nanoparticles. Using nickel oxide nanoparticles in this invention can improve the photoelectric conversion efficiency of the battery while changing the appearance evaluation criteria and increasing the yield. In this invention, the particle size of the nanoparticles can be 20-500 nm, preferably 20-200 nm. For example, 20 nm, 50 nm, 100 nm, and 200 nm. Controlling the particle size of the nanoparticles within the above-mentioned preferred range in this invention can improve the photoelectric conversion efficiency of the battery while changing the appearance evaluation criteria and increasing the yield.

[0056] The method for preparing a perovskite thin film according to the present invention includes coating a substrate precursor solution and then performing a first annealing to obtain a substrate; coating the substrate surface with a perovskite precursor solution and then performing a second annealing to obtain a perovskite thin film; wherein the substrate precursor solution contains nanoparticles or the perovskite precursor contains nanoparticles. In this invention, when nanoparticles are present in the perovskite precursor solution, the obtained perovskite thin film has continuously and uniformly distributed micropores; when nanoparticles are present in the hole transport layer precursor solution, the surface of the obtained hole transport layer has uniformly distributed particles, resulting in the obtained perovskite thin film having continuously and uniformly distributed micropores, which is beneficial for forming a perovskite thin film with uniformly distributed pores, thereby changing the appearance evaluation criteria of the perovskite thin film and improving the battery yield.

[0057] In this invention, the substrate may include a carrier transport layer, which may be a hole transport layer or an electron transport layer. In this invention, the substrate is a hole transport layer, and the substrate precursor solution may be a hole transport layer precursor solution, which further includes a hole transport layer material and a solvent.

[0058] In this invention, the hole transport layer precursor solution may contain a hole transport layer material and a solvent. In the hole transport layer precursor solution of this invention, the hole transport layer material is selected from one or more organic and inorganic hole transport materials, preferably a self-assembled molecule. In this invention, the self-assembled molecule can be selected from one or more of the following: [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2PACZ), (2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl)phosphonic acid (MeO-2PACZ), (4-(3,6-dimethyl-9H-carbazole-9-yl)ethyl)phosphonic acid (Me-4PACZ), (2-(4-(bis(4-methoxyphenyl)amino)phenyl)-1-cyanotitanyl)phosphonic acid (MPA-CPA), (4-(2,7-dibromo-9,9-dimethylacridin-10(9H)yl)butyl)phosphonic acid (DMAcPA), and poly(3,4-ethylenedioxythiophene:polystyrene sulfonate) (PEDOT:PSS).

[0059] In the hole transport layer precursor solution of the present invention, the solvent can be an alcohol solvent, preferably selected from one or more of ethanol, isopropanol, and dimethoxyethanol. In the hole transport layer precursor solution of the present invention, the concentration of the hole transport layer material can be 0.5-1.5 mg / mL, for example 0.5 mg / mL, 0.6 mg / mL, 0.7 mg / mL, 0.8 mg / mL, 0.9 mg / mL, 1.0 mg / mL, 1.0 mg / mL, 1.2 mg / mL, 1.3 mg / mL, 1.4 mg / mL, and 1.5 mg / mL.

[0060] When the substrate precursor liquid of the present invention contains nanoparticles, the presence of nanoparticles results in a uniform distribution of particles on the substrate surface. Due to the uniform distribution of particles on the substrate surface, the perovskite liquid film forms a coffee ring effect at the nanoparticle position of the hole transport layer. After annealing, the perovskite liquid film forms micropores at the nanoparticle position.

[0061] When the substrate precursor solution of this invention contains nanoparticles, the concentration of the nanoparticles can be 0.1-8 mg / mL, preferably 2-5 mg / mL, such as 2.0 mg / mL, 2.5 mg / mL, 3.0 mg / mL, 3.5 mg / mL, 4.0 mg / mL, 4.5 mg / mL, and 5.0 mg / mL. By controlling the concentration of nanoparticles in the substrate precursor solution within the above-mentioned preferred range, this invention can improve the photoelectric conversion efficiency of the battery while changing the appearance evaluation criteria and increasing the yield.

[0062] In this invention, when the substrate precursor liquid is a hole transport layer precursor liquid, and the hole transport layer precursor liquid contains nanoparticles, due to the presence of nanoparticles, there are uniformly distributed particles on the surface of the hole transport layer. Due to the uniformly distributed particles on the surface of the hole transport layer, the perovskite liquid film forms a coffee ring effect at the position of the hole transport layer nanoparticles. After annealing, the perovskite liquid film forms micropores at the position of the nanoparticles.

[0063] In this invention, when the substrate precursor solution is a hole transport layer precursor solution, the nanoparticle concentration can be 0.1-8 mg / mL, preferably 2-5 mg / mL, such as 2.0 mg / mL, 2.5 mg / mL, 3.0 mg / mL, 3.5 mg / mL, 4.0 mg / mL, 4.5 mg / mL, and 5.0 mg / mL. By controlling the nanoparticle concentration in the hole transport layer precursor solution within the above-mentioned preferred range, this invention can improve the photoelectric conversion efficiency of the battery while changing the appearance evaluation criteria and increasing the yield.

[0064] In this invention, the perovskite precursor solution may contain perovskite structural material raw materials and a solvent. In the perovskite precursor solution of this invention, the perovskite structural material raw materials may include a first perovskite material and a second perovskite material; the chemical formula of the first perovskite material may be AX, and the chemical formula of the second perovskite material may be BX2; A may be one or more selected from methylamine ions, formamidinium ions, acetamidine ions, cesium ions, and rubidium ions; B may be one or more selected from lead ions, tin ions, copper ions, and germanium ions; X may be selected from F... - I - ,Br - Cl - BF4 - PF6 - and SCN -One or more of the following are used. In the perovskite precursor solution of the present invention, the solvent may be one or more selected from dimethyl sulfoxide, N,N-dimethylformamide, acetonitrile, dimethylpyrrolidone, 2-methoxyethanol, and γ-butyrolactone. In the perovskite precursor solution of the present invention, the concentration of the perovskite structural material raw material may be 0.5-1.5 mol / L, for example 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1.0 mol / L, 1.1 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, and 1.5 mol / L.

[0065] When the perovskite precursor liquid of this invention contains nanoparticles, the presence of nanoparticles causes a coffee ring effect to form at the nanoparticle sites in the perovskite liquid film. After annealing, micropores are formed at the nanoparticle sites in the perovskite liquid film, which is beneficial for forming a perovskite film with uniformly distributed pores. This changes the appearance evaluation criteria of the perovskite film and improves the battery yield.

[0066] When the perovskite precursor solution of this invention contains nanoparticles, the concentration of the nanoparticles can be 0.1-8 mg / mL, preferably 2-5 mg / mL, such as 2.0 mg / mL, 2.5 mg / mL, 3.0 mg / mL, 3.5 mg / mL, 4.0 mg / mL, 4.5 mg / mL, and 5.0 mg / mL. By controlling the concentration of nanoparticles in the perovskite precursor solution within the above-mentioned preferred range, this invention can improve the photoelectric conversion efficiency of the battery while changing the appearance evaluation criteria and increasing the yield.

[0067] In this invention, the coating precursor solution can be applied by spin coating, blade coating, slot coating, or spray coating. The perovskite thin film of this invention is prepared by a solution method. In this invention, the coating precursor solution can be applied by spin coating, blade coating, slot coating, or spray coating.

[0068] In this invention, the temperature of the first annealing can be 100℃-120℃, for example, 100℃, 105℃, 110℃, 115℃, or 120℃. The time for the first annealing can be 2-10 minutes, for example, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, or 10 minutes. The temperature of the second annealing can be 130-150℃, for example, 130℃, 135℃, 140℃, 145℃, or 150℃. The time for the second annealing can be 15-30 minutes, for example, 15 minutes, 20 minutes, 25 minutes, or 30 minutes.

[0069] This invention provides a perovskite solar cell comprising any of the perovskite thin films described in this invention or perovskite thin films prepared by any of the methods of this invention. This invention also provides a four-terminal stacked solar cell, comprising a top cell and a bottom cell, wherein the top cell comprises any of the perovskite solar cells described in this invention, and the bottom cell comprises a crystalline silicon solar cell.

[0070] This invention provides a four-terminal stacked module comprising any of the four-terminal stacked solar cells of this invention. The four-terminal stacked module of this invention includes perovskite solar cells and crystalline silicon solar cells.

[0071] In this invention, the connection between the perovskite solar cell and the crystalline silicon solar cell can be in series, in parallel, or independently. In some embodiments, the stacked four-terminal assembly includes a perovskite solar cell, a first encapsulation layer, a crystalline silicon solar cell, a second encapsulation layer, a backsheet, and an edge water-blocking layer.

[0072] In this invention, the perovskite solar cell includes perovskite cells connected in series or in parallel. In this invention, the perovskite solar cell includes inverted perovskite cells. In some embodiments, the perovskite solar cell includes inverted perovskite cells or conventional perovskite cells connected in series or in parallel.

[0073] In this invention, the crystalline silicon cell includes crystalline silicon cells connected in series; the crystalline silicon cell can be one or more selected from emitter and back passivation cell technology, oxide passivation contact cell, intrinsic thin film heterojunction cell and back contact cell; the crystalline silicon cell can be an N-type cell or a P-type cell.

[0074] In this invention, the ratio of incident light penetrating the perovskite cell to the crystalline silicon cell across the entire wavelength range (350nm-1200nm) can be 1%-10%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%.

[0075] In this invention, the inverted perovskite solar cell may sequentially include, from bottom to top, a transparent conductive substrate, a hole transport layer, the perovskite thin film described in this invention, an electron transport layer, and a transparent electrode layer; the transparent conductive substrate may include a substrate and a front electrode layer.

[0076] In some perovskite / crystalline silicon four-terminal stacked modules, the perovskite cell is the perovskite top cell, and the crystalline silicon cell is the crystalline silicon bottom cell.

[0077] In this invention, the electron transport layer may be one or more selected from isomethyl [6,6]-phenyl-C71-butyrate (PCBM), C60 and indene-C60 diadduct A (ICB).

[0078] In this invention, the front electrode layer and the transparent electrode layer can each be independently selected from one or more of indium tin oxide (ITO), fluorine-doped tin oxide (FTO), tungsten-doped indium oxide (IWO), and aluminum-doped zinc oxide (AZO).

[0079] Compared with the prior art, the present invention has the following beneficial technical effects: (1) The perovskite thin film of the present invention has uniformly distributed micropores, which changes the appearance standard of the product and is conducive to improving the yield of the product; the hole transport layer and the electron transport layer at the location of the pores form a PN junction, which can ensure the generation of leakage current; in addition, since the charge lateral transport capability of perovskite is poor, the presence of pores will not affect the electrical performance of perovskite battery. (2) By designing the processing method of perovskite thin film, the present invention reduces the processing difficulty of perovskite film by making the perovskite film have pores. (3) When the perovskite thin film of the present invention is used in a perovskite / crystalline silicon four-terminal stacked module, the light incident surface transmits through the perovskite top cell and the crystalline silicon bottom cell to present an overall black effect. The presence of micro-pores in the perovskite thin film does not affect the overall visual effect. The presence of micro-pores in the perovskite thin film allows some light to pass through the pores and directly enter the crystalline silicon bottom cell, thereby increasing the current of the bottom cell and increasing the photoelectric conversion efficiency of the perovskite / crystalline silicon four-terminal stacked module.

[0080] The present invention will be described below by way of specific embodiments. It should be understood that these embodiments are merely illustrative and are not intended to limit the scope of the invention. The methods, reagents, and materials used in the embodiments are conventional methods, reagents, and materials in the art, unless otherwise stated. The raw material compounds in the embodiments are all commercially available.

[0081] In the embodiments and comparative examples of this invention, nickel oxide nanoparticles manufactured by Sigma with product number 67130 (50nm) and nickel oxide nanoparticles manufactured by Sigma with product number 774545 (20nm×10μm nanowires) were ground and sorted to obtain the nickel oxide nanoparticles in the embodiments and comparative examples.

[0082] In this embodiment of the invention, the manufacturer of the alumina nanoparticles is Sigma, and the product number is 702129 (50nm).

[0083] Example 1

[0084] This embodiment is prepared according to the following steps. Figure 2 The perovskite / crystalline silicon four-terminal stacked module shown: FAI, PbI2, MACl, MAI, and CsI powders were mixed in a specific molar ratio and dissolved in 1 mL of a mixed solvent (DMF and NMP in a 5:1 volume ratio). Then, NiOx nanoparticles with a particle size of 50-200 nm were added to obtain a NiOx nanoparticle concentration of 5 mg / mL and a CsI concentration of 1 mg / mL. 0.05 FA 0.9 MA 0.05 A perovskite precursor solution with a PbI3 concentration of 1 M was prepared; Me-4PACZ was dissolved in ethanol to prepare a self-assembled molecule precursor solution with a Me-4PACZ concentration of 1 mg / mL.

[0085] 1. Clean a 300mm×400mm FTO glass and dry it with nitrogen to obtain a transparent conductive FTO substrate; 2. Using a 1064nm laser, P1 lines are scribed on the FTO transparent conductive substrate, penetrating the front electrode layer (the FTO layer is the front electrode layer), forming equally spaced P1 grooves that penetrate the FTO layer, wherein the width of P1 is 20μm; 3. A 15 nm NiOx layer was prepared by magnetron sputtering on an FTO transparent conductive substrate with P1 grooves etched. Then, a hole transport layer precursor liquid was coated on the surface of the NiOx layer to obtain a uniform liquid film. After annealing, a Me-4PACZ solid film was obtained. The NiOx layer and the Me-4PAC solid film together form a hole transport layer. 4. A uniform perovskite liquid film is obtained by coating a perovskite precursor liquid with a slit on the surface of the hole transport layer. The film is then subjected to vacuum flash evaporation (VCD) and annealing processes to obtain a perovskite solid film, namely a perovskite (PVSK) layer. 5. A 20 nm C60 layer was prepared by vapor deposition on the surface of a perovskite thin film, and a 20 nm SnO2 layer was prepared on the surface of the C60 layer by atomic layer deposition (ALD). The C60 layer and the SnO2 layer served as electron transport layers. 6. Use a 532nm laser to scribing P2 lines to form P2 grooves that penetrate the NiOx / PVSK / C60 / SnO2 layers (hole transport layer / perovskite thin film / electron transport layer). P2 is 50μm wide, located to the right of P1, and the distance between P2 and P1 is 20μm. 7. A 230 nm ITO layer was prepared on the surface of the hole transport layer / perovskite thin film / electron transport layer after P2 grooves were etched by magnetron sputtering as a transparent electrode layer; 8. Use a 532nm laser to scribing P3 lines to form a P3 groove that runs through PVSK / C60 / SnO2 / ITO (perovskite active layer / electron transport layer / transparent electrode layer). The P3 is 150μm wide, located to the right of P2, and the distance between P3 and P2 is 50μm. 9. After edge cleaning and lead connection, a reverse perovskite solar cell is obtained (e.g., Figure 1 (as shown); 55 inverted perovskite solar cells are connected in series to form a perovskite top cell; 10. An edge water-blocking layer (using butyl rubber) is placed around the backplate (glass), second encapsulation layer (using TPO material in this embodiment), crystalline silicon bottom cell (using TOPCon cell in this embodiment), first encapsulation layer (using TPO material in this embodiment), and perovskite top cell, which are stacked sequentially. Then, the assembly is placed in a laminator, and after degassing and hot pressing, a perovskite / crystalline silicon four-terminal stacked module is formed (e.g., Figure 2 (As shown).

[0086] Example 2

[0087] The other conditions in this embodiment are the same as in Embodiment 1, except that the perovskite precursor solution and the self-assembled molecule precursor solution are different in this embodiment. Specifically, in this embodiment, FAI, PbI2, MACl, MAI, and CsI powders are mixed in a molar ratio, and 1 mL of a mixed solvent (the volume ratio of DMF to NMP in the mixed solvent is 5:1) is added to dissolve them to obtain CsI. 0.05 FA 0.9 MA 0.05 A perovskite precursor solution with a PbI3 concentration of 1M was prepared; Me-4PACZ and 50-200nm NiOx nanoparticles were dissolved in ethanol to prepare a self-assembled molecular precursor solution with a NiOx nanoparticle concentration of 5mg / mL and a Me-4PACZ concentration of 1mg / mL.

[0088] Example 3

[0089] The other conditions in this embodiment are the same as in Embodiment 1, except that the NiOx nanoparticles are replaced with AlOx nanoparticles with a particle size of 50 nm.

[0090] Example 4

[0091] The other conditions in this embodiment are the same as in Embodiment 1, except that the particle size of the NiOx nanoparticles is replaced with 20-100 nm.

[0092] Example 5

[0093] The other conditions in this embodiment are the same as in Embodiment 1, except that the particle size of the NiOx nanoparticles is replaced with 100-500 nm.

[0094] Example 6

[0095] The other conditions in this embodiment are the same as in Example 1, except that the concentration of NiOx nanoparticles is replaced with 2 mg / mL.

[0096] Example 7

[0097] The other conditions in this embodiment are the same as in Example 1, except that the concentration of NiOx nanoparticles is replaced with 8 mg / mL.

[0098] Comparative Example 1

[0099] The other conditions in this embodiment are the same as in Example 1, the only difference being the perovskite precursor solution used in this comparative example. Specifically, in this embodiment, FAI, PbI2, MACl, MAI, and CsI powders are mixed in a molar ratio, and 1 mL of a mixed solvent (the volume ratio of DMF to NMP in the mixed solvent is 5:1) is added to dissolve them, thus obtaining CsI. 0.05 FA 0.9 MA 0.05 A perovskite precursor solution with a PbI3 concentration of 1 M was prepared. The perovskite thin film prepared in this comparative example showed good appearance and no obvious defects.

[0100] Comparative Example 2

[0101] The conditions of Comparative Example 1 were repeated, but the perovskite film prepared in this comparative example had an abnormal appearance, with obvious pores and scratches on the film layer.

[0102] The conditions of Comparative Example 1 were repeated 10 times, and the number of times a perovskite film with good appearance was obtained was 5, so the yield was 50%.

[0103] Test Example 1

[0104] Photoluminescence mapping (PL Mapping) test: The perovskite films prepared in Examples 1-7 and Comparative Examples 1-2 were removed from the glass substrate. 10cm × 10cm samples were taken from the four corners and center of the perovskite film (edge ​​1, edge 2, edge 3, edge 4, and center 5), respectively, and placed on the sample testing stage of the PL Mapping device. The test chamber door was closed to ensure the test results were not interfered with by external light sources. The excitation light source power was set to 100%, the exposure time to 2 seconds, and the original black and white image was automatically obtained. The black and white image was rendered using the device's built-in software to obtain the color image shown. The "Nanomeasurer" software was used to statistically analyze the image to obtain the area of ​​individual pores and the pore distribution density.

[0105] Table 1: Individual pore area of ​​perovskite thin films prepared in Examples 1-7

[0106] Table 2: Pore distribution density of perovskite films prepared in Examples 1-7

[0107] Figure 10 The perovskite film is free of pores and black spots, and is relatively uniform overall.

[0108] In the perovskite films prepared in Examples 1-7 of this invention, the distance between the center point of the nanoparticles and the center point of the coffee ring is ≤L / 2; L is the longest distance from the center point of the coffee ring to the edge of the coffee ring, which indicates that the nanoparticles are all located in the center of the coffee ring.

[0109] Test Example 2

[0110] Photovoltaic performance testing: Under the standard solar spectrum of AM 1.5G at 25℃, a solar simulator was used to test the current output of the perovskite top-mounted / crystalline silicon bottom-mounted perovskite / crystalline silicon four-terminal stacked modules at different voltages using examples 1-7 and comparative examples 1-2. The corresponding current-voltage (IV) characteristic curves were plotted. The cell surface area was 785.3 cm². 2 The incident light power (pin) is 1000 W / m. -2 The photoelectric properties (open-circuit voltage, short-circuit current density, fill factor, and photoelectric conversion efficiency) of the perovskite top cell, crystalline silicon bottom cell, and perovskite / crystalline silicon four-terminal stacked module prepared in Examples 1-7 and Comparative Examples 1-2 were obtained based on the characteristic curves.

[0111] (1) Open circuit voltage (Voc): The voltage value when the current is zero.

[0112] (2) Short-circuit current density (Jsc): The current value when the voltage is zero is the short-circuit current (Isc), and the current on a unit cell surface area is the short-circuit current density.

[0113] (3) Fill factor (FF): The ratio of the battery's maximum output power (Pmax) to the product of the open-circuit voltage and the short-circuit current. The formula is (Pmax / Voc) Isc), where the maximum power point is the point where the battery output power reaches its maximum value.

[0114] (4) Photoelectric conversion efficiency (PCE): Photoelectric conversion efficiency refers to the ratio of maximum output power to incident light power (Pin), and the calculation formula is (Pmax / Pin). 100%.

[0115] The photoelectric performance test results of the perovskite top cell, crystalline silicon bottom cell, and perovskite / crystalline silicon four-terminal stacked module prepared in Examples 1-7 and Comparative Example 1 are shown in Table 3.

[0116] Table 3: Photoelectric performance of perovskite top cells, crystalline silicon bottom cells, and perovskite / crystalline silicon four-terminal stacked modules prepared in Examples 1-7 and Comparative Examples 1-2

[0117] Currently, most companies in the industry use the standard of no visible holes for a good battery appearance. Visible holes result in poor appearance. The perovskite film prepared in Comparative Example 1 is uniform and continuous, with a good appearance and no obvious defects. However, in the actual preparation of large-area perovskite films, irregular and irregular holes often appear, causing poor appearance. Although the perovskite film prepared in Comparative Example 2 shows no significant difference in photoelectric performance of the perovskite battery, its appearance is poor. In this invention, the addition of nanoparticles results in uniformly distributed micropores in the perovskite film, which can change the appearance judgment standard, avoid appearance defects caused by holes, and improve the yield of the four-terminal stacked battery. Furthermore, due to the presence and obstruction of the bottom cell, smaller visible holes in the upper part of the perovskite top cell of the four-terminal stacked module of this invention become difficult to observe with the naked eye after encapsulation into a four-terminal stacked module.

Claims

1. A perovskite thin film, characterized in that, The perovskite film has uniformly distributed pores; the pores are in the shape of coffee-colored rings and penetrate the perovskite film; the area of ​​a single pore is 0.5 μm. 2 -10mm 2 The distribution density of the pores is 1-100 pores / cm². 2 The term "uniform distribution" refers to the fact that the area range of individual pores in any two randomly selected regions of the perovskite film with the same area is the same, and the distribution density error of the pores in the two randomly selected regions with the same area is less than 10%, wherein the area of ​​the two randomly selected regions with the same area is ≥100 cm². 2 .

2. The perovskite thin film as described in claim 1, characterized in that, The perovskite film comprises perovskite structural material and nanoparticles.

3. The perovskite thin film as described in claim 2, characterized in that, The nanoparticles have a particle size of 20-500 nm; and / or The nanoparticles include one or both of nickel oxide nanoparticles and aluminum oxide nanoparticles.

4. The perovskite thin film as described in claim 3, characterized in that, The nanoparticles have a particle size of 20-200 nm; and / or The nanoparticles are nickel oxide nanoparticles.

5. The perovskite thin film according to claim 1, characterized in that, The nanoparticle is located at the center of the coffee ring; the center position means that the distance between the center point of the nanoparticle and the center point of the coffee ring is ≤ L / 2; L is the longest distance from the center point of the coffee ring to the edge of the coffee ring.

6. The perovskite thin film according to claim 1, characterized in that, The area of ​​each individual hole is 0.5 μm. 2 -1000μm 2 .

7. The perovskite thin film according to claim 1, characterized in that, The area of ​​each individual hole is 0.5 μm. 2 -500μm 2 .

8. The perovskite thin film according to claim 1, characterized in that, The area of ​​each individual hole is 0.5 μm. 2 -200μm 2 .

9. A method for preparing the perovskite thin film according to claim 1, characterized in that, The method includes coating a substrate precursor liquid, followed by a first annealing to obtain a substrate; coating a perovskite precursor liquid on the substrate surface, followed by a second annealing to obtain a perovskite film; wherein the substrate precursor liquid contains nanoparticles or the perovskite precursor contains nanoparticles.

10. The method as described in claim 9, characterized in that, The method has one or more of the following characteristics: The substrate precursor liquid can be applied by spin coating, blade coating, slot coating, or spraying. The perovskite precursor solution can be applied by spin coating, blade coating, slot coating, or spray coating. The temperature for the first annealing is 100-120℃; The second annealing time is 2-10 minutes; The temperature for the first annealing is 130-150℃; The second annealing time is 15-30 minutes. When the substrate precursor solution contains the nanoparticles, the concentration of the nanoparticles is 0.1-8 mg / mL; When the perovskite precursor solution contains the nanoparticles, the concentration of the nanoparticles is 0.1-8 mg / mL; The substrate includes a carrier transport layer, which is either a hole transport layer or an electron transport layer. The perovskite precursor solution also contains perovskite structural material raw materials and solvents.

11. The method as described in claim 10, characterized in that, In the perovskite precursor solution, the concentration of the perovskite structural material raw material is 0.5-1.5 mol / L; and / or The substrate is a hole transport layer, the substrate precursor liquid is a hole transport layer precursor liquid, and the hole transport layer precursor liquid further comprises hole transport layer material and solvent.

12. The method as described in claim 11, characterized in that, In the hole transport layer precursor solution, the concentration of the hole transport layer material is 0.5-1.5 mg / mL.

13. A perovskite solar cell comprising a perovskite thin film according to any one of claims 1-8 or a perovskite thin film prepared by any one of claims 9-12.

14. A four-terminal stacked battery, characterized in that, The four-terminal stacked solar cell includes a top cell and a bottom cell, the top cell being a perovskite solar cell as described in claim 13, and the bottom cell being a crystalline silicon solar cell.

15. A four-terminal stacked assembly, characterized in that, The four-terminal stacked assembly includes the four-terminal stacked battery of claim 14.

16. The four-terminal stacked assembly as described in claim 15, characterized in that, The four-terminal stacked assembly has one or more of the following characteristics: The percentage of incident light penetrating the perovskite solar cell and reaching the crystalline silicon solar cell across the entire wavelength range is 1%-10%. The perovskite solar cell includes perovskite solar cells connected in series or in parallel. The crystalline silicon cell comprises crystalline silicon cells connected in series; The perovskite solar cell and the crystalline silicon solar cell can be connected in series, in parallel, or independently.

Images