Perovskite precursor solution, perovskite solar cell and preparation method

Abstract

The present application relates to the technical field of solar cells, and in particular to a perovskite precursor solution, a perovskite solar cell and a preparation method. The perovskite precursor solution comprises: a perovskite material, an additive, and an organic solvent; the additive comprises a methylamine compound and an organic salt, and the methylamine compound or the organic salt contains chloride ions; the perovskite material is an ABX3 structure; A is a monovalent cation; B is a divalent cation; and X is a monovalent anion. The present application adds additives to the perovskite precursor solution, and the organic salt can induce the formation of a two-dimensional structure of the perovskite crystal, and restrict the growth of the perovskite crystal to a two-dimensional plane; the methylamine ions and chloride ions can promote the nucleation and expansion of the crystal to form larger grains; the chloride ions make the perovskite crystal grow in a direction perpendicular to the substrate on the basis of the two-dimensional structure, forming a vertical two-dimensional perovskite light-absorbing layer, effectively improving the carrier migration rate, and improving the efficiency and stability of the battery.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a perovskite precursor solution, a perovskite solar cell and a preparation method thereof. Background Art

[0002] Perovskite has excellent properties such as good light absorption ability, low exciton binding energy and long carrier diffusion length. It has attracted much attention in the past few years. The photoelectric conversion efficiency of perovskite solar cells prepared by it is high. In addition, perovskite solar cells have the characteristics of simple structure, simple preparation process and low cost, and have gradually become a very competitive solar cell.

[0003] Solar energy is mainly used to generate electricity through solar cells. Thanks to the high fluorescence quantum yield and electron mobility, three-dimensional perovskites can be widely used in optoelectronic devices such as solar cells. As the efficiency of three-dimensional perovskite solar cells continues to improve, their stability has also received more and more attention. Two-dimensional perovskite cells have better moisture resistance than three-dimensional perovskite cells, making the environmental stability of two-dimensional perovskite cells much higher than that of three-dimensional perovskite cells. However, the low carrier mobility and irregular crystal orientation of two-dimensional perovskite cells have led to low photoelectric conversion efficiency of the cells, which seriously restricts its industrialization process.

[0004] It should be noted that the above content is not necessarily prior art, nor is it intended to limit the scope of patent protection of this application. Summary of the invention

[0005] The embodiments of the present application provide a perovskite precursor solution, a perovskite solar cell, and a preparation method to solve or alleviate one or more of the technical problems raised above.

[0006] In a first aspect, an embodiment of the present application provides a perovskite precursor solution, comprising: a perovskite material, an additive, and an organic solvent; Wherein, the additive comprises a methylamine compound and an organic salt, and the methylamine compound or the organic salt contains chloride ions; The perovskite material is of ABX3 structure; A is a monovalent cation; B is a divalent cation; and X is a monovalent anion.

[0007] Optionally, the organic salt includes one or more of an organic ammonium salt and an organic sulfonium salt.

[0008] Optionally, the organic ammonium salt includes one or more of tetramethylammonium iodide, tetraethylammonium iodide, tetramethylammonium bromide, tetramethylammonium chloride, tetramethylammonium hydrogen sulfate, tetraethylammonium cyanide, and ethylenediamine iodide.

[0009] Optionally, the organic sulfonium salt includes one or more of trimethylsulfonium iodide and triethylsulfonium iodide.

[0010] Optionally, the methylamine compound includes one or more of methylamine chloride, methylamine thiocyanate, methylamine acetate, methylamine formate, and methylamine trifluoroacetate.

[0011] Optionally, in the perovskite precursor solution, the concentration of the additive is 0.5-1.5 mg / ml.

[0012] Optionally, the molar ratio of the organic salt to the methylamine compound is 1-5.

[0013] Optionally, the organic solvent includes one or more of DMF (N,N-dimethylformamide), DMSO (dimethyl sulfoxide), GBL (γ-butyrolactone) and NMP (N-methyl-2-pyrrolidone).

[0014] In a second aspect, an embodiment of the present application provides a perovskite solar cell, comprising: A substrate, a hole transport layer, a perovskite light absorption layer, a composite passivation layer, and an electron transport layer are sequentially stacked along a set direction; Wherein, the perovskite light-absorbing layer is prepared from the aforementioned perovskite precursor solution.

[0015] In a third aspect, an embodiment of the present application provides a method for preparing a perovskite solar cell, comprising the following steps: providing a substrate; forming a hole transport layer on the upper surface of the substrate; Placing the above-mentioned perovskite precursor solution on the upper surface of the hole transport layer to form a perovskite light absorbing layer; A composite passivation layer and an electron transport layer are sequentially formed on the perovskite light absorption layer.

[0016] Optionally, before forming the perovskite light absorbing layer, the method further comprises: dissolving an organic salt in an alcohol solvent to form a seed layer solution; Placing the seed layer solution on the upper surface of the hole transport layer to form the seed layer; Wherein, the concentration of the seed layer solution is 0.05-0.2 mg / ml.

[0017] The above technical solution adopted in the embodiment of the present application may have the following advantages: By adding additives (methylamine compounds and organic salts) to the perovskite precursor solution, the organic salts can combine with the perovskite material through large-volume cations to induce the formation of a two-dimensional structure of the perovskite crystal, effectively limiting the growth of the perovskite crystal to a two-dimensional plane; then the methylamine ions and chloride ions can promote the nucleation and expansion of the crystal, allowing the crystal to further grow on the basis of the two-dimensional structure to form larger grains; finally, the chloride ions can adjust the halogen distribution in the perovskite crystal, allowing the perovskite crystal to grow in a direction perpendicular to the substrate on the basis of the two-dimensional structure, thereby forming a vertical two-dimensional perovskite light-absorbing layer, effectively improving the light absorption capacity and carrier migration rate of the battery, thereby improving the efficiency and stability of perovskite solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

[0019] Figure 1 It is a schematic diagram of the structure of the perovskite tandem solar cell provided in Example 1 of the present application.

[0020] Figure 2 This is the XRD characterization diagram of the perovskite in Example 1 of the present application.

[0021] Figure 3 It is the XRD characterization diagram of comparative example 1 of the present application.

[0022] Description of reference numerals: 1. Intermediate composite layer; 2. Hole transport layer; 3. Seed layer; 4. Perovskite light absorption layer; 5. First passivation layer; 6. Second passivation layer; 7. Electron transport layer; 8. Buffer layer; 9. First transparent conductive layer; 10. Anti-reflection layer; 11. First electrode; 12. Second electrode; 13. Second transparent conductive layer; 14. P-type non- / microcrystalline silicon layer; 15. Third passivation layer; 16. Silicon substrate; 17. Fourth passivation layer; 18. N-type non- / microcrystalline silicon layer. DETAILED DESCRIPTION

[0023] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings. In the accompanying drawings, for clarity, the sizes of layers, regions, elements and their relative sizes may be exaggerated. Wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limitations on the present application. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0024] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there is no intervening element or layer. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present disclosure, the first element, component, region, layer or part discussed below can be represented as the second element, component, region, layer or part. And when the second element, component, region, layer or part is discussed, it does not indicate that the present application discloses the existence of the first element, component, region, layer or part.

[0025] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0026] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0027] In the present application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to an integer in the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical range disclosed in the present application should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows for broadly including quantitative intervals such as percentage intervals, ratio intervals, and ratio intervals.

[0028] Hereinafter, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings. It should be noted that these exemplary embodiments can be implemented in many different forms and should not be construed as being limited to the embodiments described herein.

[0029] The embodiment of the present application provides a perovskite precursor solution. The perovskite precursor solution may include: a perovskite material, an additive, and an organic solvent; The additives include methylamine compounds and organic salts, and the methylamine compounds or organic salts contain chloride ions; the perovskite material has an ABX3 structure; A is a monovalent cation; B is a divalent cation; and X is a monovalent anion.

[0030] In this embodiment, by adding additives to the perovskite precursor solution, the organic salt can combine with the perovskite material through a large volume of cations to induce the formation of a two-dimensional structure of the perovskite crystal, effectively limiting the growth of the perovskite crystal to a two-dimensional plane; then the methylamine ions and chloride ions can promote the nucleation and expansion of the crystal, so that the crystal can further grow on the basis of the two-dimensional structure to form larger grains; the chloride ions can adjust the halogen distribution in the perovskite crystal, so that the perovskite crystal grows in a direction perpendicular to the substrate on the basis of the two-dimensional structure, thereby forming a vertical two-dimensional perovskite light-absorbing layer, effectively improving the light absorption capacity and carrier migration rate of the battery, thereby improving the efficiency and stability of the perovskite solar cell. In addition, it should be noted that the structure of the two-dimensional perovskite light-absorbing layer prepared in this application is still ABX3, and the high-quality vertical growth of the perovskite material is achieved without significantly changing the perovskite light-absorbing layer, and the anions of the additive volatilize after the two-dimensional perovskite light-absorbing layer is annealed to assist in crystallization, and do not participate in the material composition of the two-dimensional perovskite light-absorbing layer.

[0031] In an optional embodiment, the organic salt includes one or more of an organic ammonium salt and an organic sulfonium salt. The organic ammonium salt includes one or more of tetramethylammonium iodide, tetraethylammonium iodide, tetramethylammonium bromide, tetramethylammonium chloride, tetramethylammonium hydrogen sulfate hydrate, tetramethylammonium hydrogen sulfate, tetraethylammonium cyanide, and ethylenediamine iodide.

[0032] In this embodiment, the organic salt can provide a large volume of organic cations to replace the cations in the perovskite crystal. The organic cations are distributed on the surface or grain boundaries of the perovskite during the growth of the perovskite crystal, limiting the growth of the perovskite crystal in the vertical direction, thereby promoting the formation of the two-dimensional structure of the perovskite. In addition, the organic cations in the organic salt can also passivate the grain boundary defects and reduce the ion migration rate of the inorganic part, thereby improving the long-term stability of the perovskite light-absorbing layer. The halogen anions in some organic salts can coordinate with the cations in the perovskite material, thereby regulating the nucleation and growth process of the perovskite crystal and improving the quality of the perovskite crystal.

[0033] In an optional embodiment, the organic sulfonium salt includes one or more of trimethylsulfonium iodide and triethylsulfonium iodide. The sulfonium in the organic sulfonium salt is connected to three groups and has a pair of lone electron pairs, which can occupy the halogen vacancy of the free lead in the perovskite, thereby achieving a passivation effect on the perovskite.

[0034] In an optional embodiment, the methylamine compound includes one or more of methylamine chloride, methylamine thiocyanate, methylamine acetate, methylamine formate, and methylamine trifluoroacetate.

[0035] In this embodiment, the methylamine ions in the above-mentioned methylamine compound can form an intermediate complex with the perovskite material, thereby regulating the nucleation and growth of the perovskite crystals, and promoting the full growth of the perovskite crystals to form larger grains. In addition, the formation of more large perovskite grains can reduce the number of grain boundaries, and the grain boundaries are often the main location of carrier recombination. Therefore, the methylamine ions optimize the grain growth direction, form larger grains, reduce defects, and improve the photoelectric properties of the perovskite film.

[0036] It should be noted that the methylamine ions and chloride ions in the above-mentioned methylammonium chloride can jointly participate in the formation of an intermediate phase complex, prolong the growth time of perovskite crystals, and thus promote the formation of large perovskite grains; the methylamine ions also help to form a dense and uniform crystal structure, and the chloride ions can also induce the growth of perovskite crystals along the vertical direction of the substrate, thereby achieving the effect of promoting the formation of larger perovskite grains and promoting the vertical growth of perovskite grains, thereby improving the photoelectric conversion efficiency of the perovskite battery.

[0037] In an optional embodiment, in the perovskite precursor solution, the concentration of the additive is 0.5~1.5 mg / ml. For example, the concentration of the additive can be 0.5 mg / ml, 0.5 mg / ml, 1.50.5 mg / ml. When the concentration of the additive is higher than 1.5 mg / ml, the additive will affect the intrinsic properties of the perovskite host material, and the additive will replace the role of the perovskite, affecting the preparation of the battery; and when the concentration of the additive is lower than 0.5 mg / ml, the concentration of the additive is too low, resulting in a discontinuous two-dimensional layer of the perovskite, thereby affecting the efficiency and stability of the battery.

[0038] In an optional embodiment, the molar ratio of the organic salt to the methylamine compound is 1-5.

[0039] In this embodiment, methylamine is also a substance at the A position of the perovskite material. When the molar ratio of the organic salt to the methylamine compound is lower than 1, excessive content of the methylamine compound will affect the intrinsic properties of the perovskite material and change the perovskite band gap; when the molar ratio of the organic salt to the methylamine compound is greater than 5, excessive content of the organic salt will also affect the performance of the perovskite main material, thereby affecting the preparation of the battery.

[0040] In an optional embodiment, the organic solvent includes one or more of DMF (N,N-dimethylformamide), DMSO (dimethyl sulfoxide), GBL (γ-butyrolactone) and NMP (N-methyl-2-pyrrolidone). The above four organic solvents all have good solubility for perovskite materials, among which DMF has a low boiling point and is easy to volatilize during the spin coating process, which helps to form a preliminary perovskite precursor film; DMSO has a high boiling point and a slow volatilization rate, which can delay the nucleation and growth process of the perovskite film, allowing the grains to have more time to grow and form larger grains, thereby reducing the defect density; GBL has a high boiling point and a slow volatilization rate. During the film formation process, GBL can delay the evaporation of the solvent, ensuring uniform growth of the film and a larger grain size; NMP has a high boiling point, which can control the crystallization rate of the perovskite film during the deposition process, allowing larger grains to grow.

[0041] An embodiment of the present application may also provide a perovskite solar cell, which includes a substrate, a hole transport layer, a perovskite light absorbing layer, a composite passivation layer, and an electron transport layer stacked in sequence along a set direction; wherein the perovskite light absorbing layer is prepared from the perovskite precursor solution of any of the above embodiments.

[0042] In some embodiments, the perovskite solar cell may be a perovskite tandem solar cell, further comprising: a bottom cell unit, the bottom cell unit being connected to the hole transport layer via an intermediate composite layer; Among them, the bottom cell unit is one of a crystalline silicon bottom cell unit, a CIGS cell, a CdTe cell, a Sb2S3 cell and a Sb2Se3 cell. CIGS cells, CdTe cells, Sb2S3 cells and Sb2Se3 cells are all different types of thin-film solar cells that convert solar photons into electrical energy by using different materials and processes. CIGS cells have high efficiency and low cost, and perform well in low light intensity environments. CdTe cells have relatively low production costs, and have high photoelectric conversion efficiency and good stability. Sb2S3 cells are an emerging type of solar cell, however, their efficiency and stability are relatively low. Sb2Se3 cells have a higher absorption coefficient and better photoelectric properties.

[0043] The embodiments of the present application may also provide a method for preparing a perovskite solar cell.

[0044] The preparation method comprises the following steps: providing a substrate; forming a hole transport layer on the upper surface of the substrate; Placing a perovskite precursor solution of any one of the above embodiments on the upper surface of the hole transport layer to form a perovskite light absorbing layer; A composite passivation layer and an electron transport layer are sequentially formed on the perovskite light absorbing layer.

[0045] In some embodiments, a buffer layer, a first transparent conductive layer, an anti-reflection layer, and a first electrode are sequentially formed on the electron transport layer.

[0046] In an optional embodiment, before forming the perovskite light absorbing layer, the method further includes: dissolving an organic salt in an alcohol solvent (ethanol) to form a seed layer solution; Placing the seed layer solution on the upper surface of the hole transport layer to form the seed layer; The concentration of the seed layer solution is 0.05~0.2mg / ml. When the concentration of the seed layer solution is higher than 0.2mg / ml, the seed layer film is too thick to hinder carrier transport; when the concentration of the seed layer solution is lower than 0.05mg / ml, the seed layer film is discontinuous, affecting the subsequent perovskite film deposition, that is, the vertical growth of two-dimensional perovskite on the seed layer.

[0047] In some embodiments, the alcohol solvent includes one or more of ethanol or isopropanol.

[0048] In this embodiment, the seed layer can provide a low-defect nucleation environment, reduce random nucleation points, and improve the uniformity of perovskite crystals; in addition, the organic cations in the seed layer can combine with metal cations (such as Pb²⁺) or halide anions (such as I⁻, Cl⁻) in the perovskite precursor solution through electrostatic interaction or hydrogen bonding, providing an initial template for the growth of perovskite crystals, inducing the orderly growth of perovskite crystals in the direction perpendicular to the substrate, and can also reduce the randomness of perovskite crystal nucleation, control the arrangement direction of perovskite crystals, and avoid subsequent large perovskite particles from directly contacting the substrate, resulting in a rough surface problem. In the embodiment of the present application, the material of the seed layer is usually selected to be the same as the organic salt in the perovskite precursor solution.

[0049] In some embodiments, the substrate may be a conductive substrate, including but not limited to indium tin oxide (ITO) transparent conductive glass, fluorine-doped tin oxide (FTO) transparent conductive glass, tungsten-doped indium oxide (IWO) transparent conductive glass, and aluminum-doped zinc oxide (AZO) transparent conductive glass. The conductive substrate may be cleaned, laser etched, ultraviolet treated, and ozone treated. The step of cleaning the conductive substrate may include: placing the conductive substrate in an ultrasonic cleaning instrument, ultrasonically cleaning with deionized water, isopropanol, and ethanol, respectively, the cleaning time of each link is 20 to 40 minutes (for example, 20 minutes, 30 minutes, 40 minutes), and then drying with nitrogen after cleaning. The step of ultraviolet treatment of the conductive substrate may include: treating the conductive substrate with a UV-zone, wherein the treatment time is 20-40 minutes (for example, 20 minutes, 30 minutes, 40 minutes). The step of ozone treatment of the conductive substrate may include: placing the conductive substrate in a reaction chamber of an ozone treatment device for treatment, ensuring that the substrate surface is exposed to ozone gas, and the treatment time is 5 to 10 minutes.

[0050] In some embodiments, the preparation material of the hole transport layer includes organic hole transport materials, inorganic hole transport materials, self-assembled monolayer materials (Self-Assembled Monolayer, referred to as SAM), etc., preferably SAM materials. The preparation materials of the hole transport layer include [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (abbreviated as 2PACZ), (2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl)phosphonic acid (abbreviated as MeO-2PACZ), (4-(3,6-dimethyl-9H-carbazole-9-yl)ethyl)phosphonic acid (abbreviated as Me-4PACZ), (2-(4-(bis(4-methoxyphenyl)amino)phenyl)-1-cyanotitanyl)phosphonic acid (abbreviated as MPA-CPA) and (4-(2,7-dibromo-9,9-dimethylacridin-10(9H)yl)butyl)phosphonic acid (abbreviated as DMAcPA), PEDOT:PSS (poly 3,4-ethylenedioxythiophene:polystyrene sulfonate), NiOx and one or more of CuSCN, placing the hole transport layer solution on the upper surface of the conductive substrate, and then preparing the hole transport layer by solution spin coating. The spin coating speed is 5000~8000rpm (for example, 5000rpm / min, 6500rpm / min, 8000rpm / min), and the time is 40~60s (for example, 40s, 50s, 60s). Finally, an annealing treatment is performed to remove the solvent, and the temperature of the annealing treatment is 100°C and the time is 10min. The solvent used in the hole transport layer solution is one or both of ethanol and isopropanol.

[0051] In some embodiments, the perovskite precursor solution is coated on the surface of the hole transport layer by a one-step spin coating method or a slit coating method to obtain a perovskite light absorbing layer. The coating speed may be 4000-5000rpm / min (e.g., 4000rpm / min, 4500rpm / min, 5000rpm / min), and the coating time may be 30-40s (e.g., 30s, 35s, 40s). The perovskite light absorbing layer includes a perovskite material and an organic solvent, the perovskite material is an ABX3 structure; A is a monovalent cation; B is a divalent cation; X is a monovalent anion; A includes one or more of methylamine, formamidine, acetamidine, cesium and rubidium; B also includes one or more of tin, copper and germanium; X includes F - ,I - Br - , Cl - , BF 4- PF 6- and SCN - One or more of .

[0052] In some embodiments, the preparation material of the electron transport layer includes PCBM ([6,6]-phenyl-C 71 -isomethyl butyrate), TiO2, SnO2, ZnO2, Al2O3, C 60 and ICBA (Indene-C 60 The electron transport layer can be prepared by spin coating, vacuum evaporation, magnetron sputtering, atomic layer deposition and the like. When the vacuum evaporation method is used, the evaporation rate is 0.2Å / s and the evaporation time is 1500s.

[0053] In some embodiments, the buffer layer is prepared from materials including BCP (2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline), MoO xThe buffer layer can be prepared by spin coating, vacuum evaporation, magnetron sputtering, atomic layer deposition and the like. When the vacuum evaporation method is used, the evaporation rate is 0.1Å / s and the evaporation time is 1500s.

[0054] In some embodiments, the material of the electrode includes, but is not limited to, one or more of Au, Ag, Al, Cu, transparent conductive oxide (TCO), graphene, and nanocrystalline silicon. The electrode can be prepared by thermal evaporation, vacuum evaporation, sputtering, atomic layer deposition, 3D printing, screen printing, inkjet printing, etc. The thickness of the electrode can be 60-100 nm.

[0055] The following specific examples further illustrate the present application, but should not be construed as limiting the present application. Without departing from the spirit and substance of the present application, modifications or replacements made to the methods, steps or conditions of the present application are within the scope of the present application.

[0056] [Example 1] like Figure 1 As shown, the perovskite solar cell is a perovskite stacked solar cell, and its specific structure includes a bottom battery unit, an intermediate composite layer 1, a hole transport layer 2, a seed layer 3, a perovskite light absorption layer 4, a composite passivation layer, an electron transport layer 7, a buffer layer 8, a first transparent conductive layer 9, an anti-reflection layer 10, and a first electrode 11 stacked from bottom to top; The bottom cell includes a second electrode 12, a second transparent conductive layer 13, a P-type non- / microcrystalline silicon layer 14, a third passivation layer 15, a silicon substrate 16, a fourth passivation layer 17, and an N-type non- / microcrystalline silicon layer 18 stacked in sequence from far away to close to the middle composite layer 1; The composite passivation layer includes a first passivation layer 5 and a second passivation layer 6 .

[0057] The specific preparation steps of perovskite tandem solar cells are as follows: S1: providing a bottom battery cell, forming an intermediate composite layer 1 on the bottom battery cell, wherein the material of the intermediate composite layer 1 is IZO, and the thickness is 10 nm, wherein the bottom battery cell is a crystalline silicon bottom battery cell; S2: Dissolve Meo-4PACz in solvent IPA, mix well to obtain a hole transport layer 2 solution with a concentration of 1 mg / ml, and spin-coat the hole transport layer 2 solution on the upper surface of the intermediate composite layer 1 by spin coating to form a hole transport layer 2 with a thickness of 1 nm; S3: dissolving the organic salt tetramethylammonium chloride in isopropanol to form a seed layer 3 solution, the concentration of the seed layer 3 solution is 0.1 mg / ml, and then using a spin coating method, the seed layer 3 solution is spin coated on the upper surface of the intermediate composite layer 1 to form a seed layer 3 with a thickness of 0.8 nm; S4: The perovskite material (Cs 0.05 MA 0.16 FA 0.8 PbI 2.28 Br 0.72 ) is dissolved in a mixed organic solvent with a volume ratio of DMF:DMSO=4:1, and then an additive with a concentration of 1 mg / ml is added, the additive is tetramethylammonium chloride and methylammonium thiocyanate, and the molar ratio of tetramethylammonium chloride and methylammonium thiocyanate is 3:1, and stirred at room temperature until it is completely dissolved to obtain a perovskite precursor solution; the perovskite precursor solution is spin-coated on the upper surface of the seed layer 3 to form a perovskite film, and the perovskite film is annealed at an annealing temperature of 70°C and an annealing time of 10 minutes; then it is heated on a heating table at a temperature of 100°C for 20 minutes to form a perovskite light-absorbing layer 4 with a thickness of 700 nm; S5: Using thermal evaporation method, a first passivation layer 5 with a thickness of 1 nm is deposited on the perovskite light absorption layer 4, wherein the material of the first passivation layer 5 is LiF x ; S6: using a spin coating method, depositing a second passivation layer 6 with a thickness of 5 nm on the perovskite light absorption layer 4, wherein the material of the second passivation layer 6 is EDAI; S7: Using thermal evaporation, deposit an electron transport layer 7 with a thickness of 10 nm on the second passivation layer 6, wherein the material of the electron transport layer 76 is C 60 ; S8: using an ALD method, depositing a buffer layer 8 with a thickness of 16 nm on the electron transport layer 7, wherein the material of the buffer layer 8 is SnO2; S9: using a magnetron sputtering method, depositing a first transparent conductive layer 9 with a thickness of 50 nm on the buffer layer 8, wherein the material of the first transparent conductive layer 9 is IZO; S10: Depositing an anti-reflection layer 10 with a thickness of 120 nm on the first transparent conductive layer 9 by evaporation, wherein the material of the anti-reflection layer 10 is MgF x ; S12: depositing a first electrode 11 with a thickness of 400 nm on the anti-reflection layer 10 by an evaporation method, wherein the material of the first electrode 11 is Ag.

[0058] [Example 2] - [Example 8] The perovskite tandem solar cell of Example 2 was prepared by referring to the preparation method of Example 1, except that in step S3 of Example 2, the additives were tetramethylammonium chloride and methylammonium thiocyanate, and the molar ratio of tetramethylammonium chloride to methylammonium thiocyanate was 1:1.

[0059] The perovskite tandem solar cell of Example 3 was prepared by referring to the preparation method of Example 1, except that in step S3 of Example 2, the additives were tetramethylammonium chloride and methylammonium thiocyanate, and the molar ratio of tetramethylammonium chloride to methylammonium thiocyanate was 5:1.

[0060] The perovskite tandem solar cell of Example 4 was prepared by referring to the preparation method of Example 1, except that in step S3 of Example 4, the additives were trimethylsulfonium iodide and methylammonium chloride in a ratio of 4:1, and the organic salt used in the seed layer solution was trimethylsulfonium iodide.

[0061] The perovskite tandem solar cell of Example 5 was prepared by referring to the preparation method of Example 1, except that in step S3 of Example 5, the additives were tetramethylammonium chloride and methylamine trifluoroacetate, and the organic salt used in the seed layer solution was tetramethylammonium chloride.

[0062] The perovskite tandem solar cell of Example 6 was prepared by referring to the preparation method of Example 1, except that in step S3 of Example 6, the additives were ethylenediamine iodide and methylammonium chloride, and the organic salt used in the seed layer solution was ethylenediamine iodide.

[0063] The perovskite tandem solar cell of Example 7 was prepared by referring to the preparation method of Example 1, except that in step S3 of Example 7, the concentration of the additive was 0.2 mg / ml.

[0064] The perovskite tandem solar cell of Example 8 was prepared by referring to the preparation method of Example 1, except that in step S3 of Example 8, the concentration of the additive was 1.5 mg / ml.

[0065] [Comparative Example 1] The perovskite solar cell of Comparative Example 1 was prepared by referring to the preparation method of Example 1, except that in step S3 of Comparative Example 1, the additive was ethylenediamine iodide.

[0066] The following is a performance test of the perovskite solar cells provided in Examples 1-8 of the present application and Comparative Example 1, so as to obtain the short-circuit current density Jsc, open-circuit voltage Voc, fill factor FF, and photoelectric conversion efficiency PCE of the corresponding battery devices. The test results are shown in Table 1.

[0067] The perovskite solar cells provided in Examples 1-8 of the present application and Comparative Example 1 were subjected to a 500-h steady-state MPP test, i.e., the ratio of the photoelectric conversion efficiency of the perovskite solar cell after outputting at the maximum power point for 500 h to the photoelectric conversion efficiency at 0 h, and the test results are shown in Table 1.

[0068] Table 1 Performance test results of perovskite tandem solar cells of Examples 1-8 and Comparative Example 1

[0069] It can be seen from Table 1 that compared with Comparative Example 1, the short-circuit current density Jsc, open-circuit voltage Voc, fill factor FF, photoelectric conversion efficiency PCE and 500h steady-state MPP test data of the perovskite tandem solar cells of Examples 1 to 8 of the present application are significantly improved, that is, the perovskite solar cell can maintain good environmental stability while improving the photoelectric conversion efficiency. Figure 2 As shown, peak 101 represents the vertical growth crystal direction of the two-dimensional perovskite. In Examples 1-8 of the present application, the addition of additives (methylamine compounds and organic salts) to the perovskite precursor solution can regulate the growth direction of the perovskite crystals under the premise of forming a two-dimensional perovskite, so that the perovskite crystals grow in a direction perpendicular to the substrate, forming a vertical two-dimensional perovskite light-absorbing layer, thereby improving the photoelectric conversion efficiency and stability of the perovskite stacked solar cell. Figure 3 As shown, peak 010 represents the horizontal perovskite crystal orientation of the two-dimensional perovskite. Therefore, the perovskite crystals of the perovskite tandem solar cell prepared in Comparative Example 1 grow horizontally, resulting in a lower efficiency of the cell.

[0070] The embodiment of the present application may also provide a photovoltaic module (not shown), wherein the photovoltaic module includes the perovskite solar cell as described above. The perovskite solar cell may be connected in series and / or in parallel with one or more other solar cells in a preset manner. Among them, a plurality of cells may form a cell string, and adjacent cells may be connected together by series welding.

[0071] The embodiment of the present application can provide a photovoltaic system, including the photovoltaic components in any of the above embodiments. The advantages of the above photovoltaic components are also possessed by the photovoltaic system, which will not be repeated here. The above photovoltaic system has a wide range of applications, not only limited to photovoltaic power stations, such as ground power stations, rooftop power stations and water power stations, but also includes various equipment and devices that use solar energy to generate electricity, such as user solar power supplies, solar street lights, solar cars and solar buildings. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this, that is to say, the photovoltaic system can be used in all fields where solar energy is required for power generation. Taking the photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a junction box and an inverter. The photovoltaic array may be an array combination of multiple photovoltaic components. For example, multiple photovoltaic components may form multiple photovoltaic arrays. The photovoltaic array is connected to a junction box. The junction box can converge the current generated by the photovoltaic array. The converged current flows through the inverter and is converted into the alternating current required by the mains power grid, and then connected to the mains network to realize solar power supply.

[0072] It should be noted that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. The orientation words "inside" and "outside" refer to the inside and outside relative to the outline of each component itself. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Therefore, the exemplary term "above..." can include both "above..." and "below..." orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used here are interpreted accordingly.

[0073] It should also be noted that "one embodiment", "another embodiment", "embodiment", etc. mentioned in this application refer to the specific features, structures or characteristics described in conjunction with the embodiment included in at least one embodiment generally described in this application. The same expression appearing in multiple places in the specification does not necessarily refer to the same embodiment. Further, when describing a specific feature, structure or characteristic in conjunction with any embodiment, it is claimed that the realization of such feature, structure or characteristic in conjunction with other embodiments also falls within the scope of this application.

[0074] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0075] It should also be noted that the above are only preferred embodiments of the present application, and the patent protection scope of the present application is not limited thereto. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A perovskite precursor solution, characterized in that: include: Perovskite materials, additives, and organic solvents; Wherein, the additive comprises a methylamine compound and an organic salt, and the methylamine compound or the organic salt contains chloride ions; The perovskite material is of ABX3 structure; A is a monovalent cation; B is a divalent cation; and X is a monovalent anion.

2. The perovskite precursor solution according to claim 1, characterized in that The organic salt includes one or more of an organic ammonium salt and an organic sulfonium salt.

3. The perovskite precursor solution according to claim 2, characterized in that The organic ammonium salt includes one or more of tetramethylammonium iodide, tetraethylammonium iodide, tetramethylammonium bromide, tetramethylammonium chloride, tetramethylammonium hydrogen sulfate, tetraethylammonium cyanide, and ethylenediamine iodide.

4. The perovskite precursor solution according to claim 2, characterized in that: The organic sulfonium salt includes one or more of trimethylsulfonium iodide and triethylsulfonium iodide.

5. The perovskite precursor solution according to any one of claims 1 to 4, characterized in that: The methylamine compound includes one or more of methylamine chloride, methylamine thiocyanate, methylamine acetate, methylamine formate, and methylamine trifluoroacetate.

6. The perovskite precursor solution according to any one of claims 1 to 4, characterized in that: In the perovskite precursor solution, the concentration of the additive is 0.5-1.5 mg / ml.

7. The perovskite precursor solution according to any one of claims 1 to 4, characterized in that: The molar ratio of the organic salt to the methylamine compound is 1-5.

8. A perovskite solar cell, characterized in that: include: A substrate, a hole transport layer, a perovskite light absorption layer, and an electron transport layer are sequentially stacked along a set direction; Wherein, the perovskite light-absorbing layer is prepared from the perovskite precursor solution according to any one of claims 1 to 7.

9. A method for preparing a perovskite solar cell, characterized in that: The steps include: providing a substrate; forming a hole transport layer on the upper surface of the substrate; Placing the perovskite precursor solution according to any one of claims 1 to 7 on the upper surface of the hole transport layer to form a perovskite light absorbing layer; An electron transport layer is formed on the perovskite light absorbing layer.

10. The method for preparing a perovskite solar cell according to claim 9, characterized in that: Before forming the perovskite light absorbing layer, the method further comprises: dissolving an organic salt in an alcohol solvent to form a seed layer solution; Placing the seed layer solution on the upper surface of the hole transport layer to form the seed layer; Wherein, the concentration of the seed layer solution is 0.05-0.2 mg / ml.

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