Perovskite thin film preparation method and cell

Abstract

The invention provides a perovskite thin film preparation method and a battery, and the method comprises the steps: providing a substrate, and depositing an inorganic substrate layer on the substrate; soaking the inorganic substrate layer in an aggressive agent for erosion to obtain a porous inorganic substrate layer with a micro-nano porous structure; coating organic salt reaction ink on the porous inorganic substrate layer, and drying the organic salt reaction ink to form a perovskite pre-crystallization film; and annealing the pre-crystallized thin film to obtain the perovskite thin film. According to the perovskite thin film preparation method and the cell provided by the invention, the inorganic substrate layer is soaked in the aggressive agent, so that the inorganic substrate layer generates a micro-nano porous structure, and the consistency of the inorganic deposition layer is favorably controlled; during erosion, the pore diameter and porosity of the porous structure can be adjusted by controlling the concentration, time and the like of the erosion agent, and the porous inorganic substrate layer with relatively high consistency can be obtained.

Description

Technical Field

[0001] This application belongs to the field of solar cell technology, and more specifically, relates to a method for preparing perovskite thin films and a battery. Background Technology

[0002] Perovskite materials are widely used in the photovoltaic field due to their excellent photoelectric properties. The general chemical formula of perovskite materials is ABX3, where the A-site is typically a monovalent organic cation (such as methylamine cation MA⁺, formamidinium cation FA⁺) or an inorganic cation (such as Cs⁺, Rb⁺), the B-site is a divalent metal ion (such as Pb²⁺, Sn²⁺), and the X-site is a halide anion (such as I⁻, Br⁻, Cl⁻). By adjusting the composition of the A, B, and X sites, the band gap, stability, and photoelectric properties of the material can be precisely controlled to meet the needs of different application scenarios.

[0003] In the fabrication of perovskite thin films, a two-step process first deposits an inorganic substrate layer (such as PbI2), then reacts with an organic salt solution (such as MAI or FAI) to form the perovskite film. The density and crystallinity of the inorganic substrate layer directly affect the penetration and reaction efficiency of the subsequent organic salt. If the inorganic layer is too dense, the organic salt cannot penetrate sufficiently, leading to incomplete reaction and residual unconverted PbI2 and other precursors in the film. If the inorganic layer is too porous, it may form a porous film with poor mechanical strength, which is prone to cracking during subsequent annealing or device processing. Existing processes optimize the morphology of the inorganic substrate layer through solvent engineering and use mixed solvents or additives to regulate the crystallization process. However, the porosity of the inorganic layer in the fabricated perovskite film is difficult to control, resulting in complex processes, high costs, and poor consistency in large-area fabrication. Summary of the Invention

[0004] The purpose of this application is to provide a method for preparing perovskite thin films to solve the technical problem of poor consistency in the large-area preparation of perovskite thin films in the prior art.

[0005] To achieve the above objectives, the technical solution adopted in this application is: to provide a method for preparing perovskite thin films, comprising: A substrate is provided, on which an inorganic substrate layer is deposited; The inorganic substrate is immersed in an etchant to etch it, thereby obtaining a porous inorganic substrate with a micro-nano-scale porous structure. An organic salt reaction ink is coated onto the porous inorganic substrate, and the organic salt reaction ink is dried to form a perovskite pre-crystallized film. The pre-crystallized film was annealed to obtain a perovskite film.

[0006] This application embodiment uses an etchant to soak an inorganic substrate layer, resulting in a micro-nano-scale porous structure in the inorganic substrate layer. This eliminates the need for depositing the inorganic substrate layer to generate a porous structure, and the inorganic substrate layer deposition process does not require mixing solvents or adding additives to regulate the crystallization process. A dense deposition layer can be directly obtained, which is beneficial for controlling the consistency of the inorganic deposition layer. During etching, the pore size and porosity of the porous structure can be adjusted by controlling the concentration and time of the etchant. The solute in the etchant solution is uniformly dispersed, and there is no interference from the inorganic substrate layer deposition process, thereby obtaining a porous inorganic substrate layer with high consistency.

[0007] In one embodiment, the solvent of the etchant is at least one selected from isopropanol, ethanol, and n-butanol; The solute of the etchant is at least one of dimethyl sulfone, N,N-dimethylformamide, and N-methylpyrrolidone.

[0008] By employing the above-mentioned techniques, inorganic substrates can be etched to form micro-nano-scale porous structures, which facilitates solvent removal during annealing.

[0009] In one embodiment, the mass percentage of the solute in the etchant is 0.1%-70%.

[0010] By employing the aforementioned technical methods, the erosion rate can be controlled.

[0011] In one embodiment, the etchant is deposited on the surface of the inorganic substrate layer via vapor deposition, spin coating, inkjet printing, or slot coating processes; and / or, The inorganic substrate is immersed in the etchant for a period ranging from 5 s to 800 s; and / or, The etchant is dried by air blowing, vacuum flash evaporation, natural drying, or infrared heating processes; and / or, The inorganic substrate is etched and then annealed at a temperature of 50℃-300℃ for a time of 5s-2000s.

[0012] By employing the above-mentioned technical means, it is possible to soak the surface of an inorganic substrate; control the degree of erosion of the inorganic substrate; terminate the erosion reaction; and remove the solvent of the eroding agent.

[0013] In one embodiment, the inorganic substrate layer comprises AX and BX2; A is a monovalent metal cation, B is a divalent metal cation, and X is a monovalent anion; A includes Cs. + and Rb + At least one of them, wherein B includes Pb 2+ or Sn 2+ At least one of them; The X includes I- ,Br - Cl - or SCN - At least one of them.

[0014] By employing the above-mentioned technical means, it is possible to easily deposit and form an inorganic substrate layer, which can be etched by an etchant to form a porous structure.

[0015] In one embodiment, the organic salt reactive ink comprises an organic salt and an organic solvent, wherein the organic salt is CY; C is a monovalent organic cation, and Y is a monovalent anion; C includes at least one of methylamine, formamidinium, and phenylethylamine halide cations, and Y includes I - ,Br - Cl - or SCN - At least one of them; The organic solvent includes at least one of isopropanol, ethanol, and n-butanol.

[0016] By employing the above-mentioned technical means, it is possible to react and complex with the inorganic substrate layer.

[0017] In one embodiment, the organic salt reactive ink further includes a penetration enhancer, which includes at least one selected from ethylene glycol monomethyl ether, diphenyl sulfoxide, γ-lactone, dimethyl sulfone, N,N-dimethylformamide, and N-methylpyrrolidone.

[0018] By employing the above-mentioned technical means, the permeability of organic salt reaction ink can be enhanced, allowing the organic salt reaction ink to penetrate into the porous inorganic substrate layer for full reaction and reducing residue.

[0019] In one embodiment, the penetration enhancer comprises 0.1%-50% by mass.

[0020] By employing the aforementioned technical means, the infiltration rate can be controlled.

[0021] In one embodiment, the organic salt reactive ink is applied to the porous inorganic substrate layer via inkjet printing, spin coating, or slot coating processes; and / or, The organic salt reactive ink is dried by air blowing, vacuum flash evaporation, natural drying, or infrared heating processes; and / or, In the step of annealing the pre-crystallized film: the annealing temperature is 50℃-300℃, and the annealing time is 5s-2000s.

[0022] By employing the above-mentioned technical means, organic salt reaction ink can be uniformly coated on the surface of a porous inorganic substrate; the process of organic salt reactants penetrating into the porous inorganic substrate can be accelerated; and residual solvents can be removed to maintain the stability of the film.

[0023] This application also provides a battery comprising a perovskite layer, which is prepared by the method described in any of the above embodiments.

[0024] By adopting the above-mentioned technical means, it is beneficial to control the quality of the perovskite layer and the consistency of the product. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 A schematic diagram of the perovskite thin film preparation method provided in the embodiments of this application; Figure 2 for Figure 1 A schematic diagram of step S10; Figure 3 for Figure 1 A schematic diagram of step S20; Figure 4 for Figure 1 Schematic diagram of steps S30 and S40; Figure 5 This is a schematic diagram of the layer structure of Example 1; Figure 6 This is a comparison diagram of Example 1 and Comparative Examples 1-3. Detailed Implementation

[0027] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0028] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0029] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0031] Please refer to the following: Figures 1 to 4 The method for preparing perovskite thin films provided in this application embodiment will now be described. The method for preparing perovskite thin films includes: S10 provides a substrate on which an inorganic substrate layer is deposited; S20, the inorganic substrate is immersed in an etchant to etch it, and a porous inorganic substrate with a micro-nano-scale porous structure is obtained. S30, an organic salt reaction ink is coated on a porous inorganic substrate, and the organic salt reaction ink is dried to form a perovskite pre-crystallized film; S40, the pre-crystallized film is annealed to obtain a perovskite film.

[0032] It should be noted that, in the embodiments of this application, when depositing an inorganic substrate layer on the substrate, it may be, but is not limited to, a dense inorganic substrate layer formed by depositing inorganic substrate materials (inorganic salt solutions, etc.). The inorganic substrate layer has no porous structure, and therefore does not require mixing solvents or additives to regulate the crystallization process and adjust pore formation, making consistency easier to control during fabrication. The etchant is deposited on the inorganic substrate layer after its formation, and erodes the dense inorganic substrate layer to create a micro / nano-scale porous structure, thereby forming a porous inorganic substrate layer. The role of the organic salt reactive ink is to react and complex with the materials in the porous inorganic substrate layer, so that a perovskite pre-crystallized film can be formed after drying. Its drying process facilitates the accelerated penetration of organic salts into the porous inorganic substrate layer.

[0033] In this embodiment, by immersing the inorganic substrate layer with an etchant, a micro-nano-scale porous structure is formed on the inorganic substrate layer. This eliminates the need for pre-deposition of the inorganic substrate layer, as the deposition process does not require solvent mixing or additives to regulate the crystallization process. A dense deposition layer can be directly achieved, which is beneficial for controlling the consistency of the inorganic deposition layer. During etching, the pore size and porosity of the porous structure can be adjusted by controlling the concentration and time of the etchant. The solute in the etchant solution is uniformly dispersed, eliminating interference from the inorganic substrate deposition process. The reaction rate is essentially uniform throughout the immersion etching process, resulting in a highly consistent porous inorganic substrate layer. After the formation of the porous inorganic substrate layer, its permeability is improved. By coating with an organic salt reactive ink, the ink penetrates into the porous structure, thereby improving the uniformity of the interfacial reaction and resulting in a more uniform film thickness and composition distribution.

[0034] In one embodiment of this application, the solvent of the etchant is at least one selected from isopropanol, ethanol, and n-butanol; the solute of the etchant is at least one selected from dimethyl sulfone, N,N-dimethylformamide, and N-methylpyrrolidone. This facilitates the dissolution of the solute in the etchant and prevents the dissolution of the inorganic substrate layer, thereby enabling control of the reaction degree, precise regulation of the pore size and porosity of the micro / nano-scale porous structure, and convenient solvent removal in subsequent annealing processes.

[0035] In one embodiment of this application, the mass percentage of the solute in the etchant is 0.1%-70%. This allows for concentration-based control of the reaction rate to meet the requirements of different micro / nano-scale porous etching processes. The mass percentage of the solute in the etchant can be adjusted based on the reaction rate, temperature, time, pore size, and porosity of the etchant, etc. For example, the mass percentage of the solute in the etchant can be any value between 0.1% and 70%, such as 1%, 5%, 15%, 30%, 40%, 50%, or 60%.

[0036] In one embodiment of this application, the etchant is deposited on the surface of the inorganic substrate layer via vapor deposition, spin coating, inkjet printing, or slot coating. This ensures that the etchant is uniformly applied to the surface of the inorganic substrate layer, resulting in sufficient and uniform contact between the surface of the inorganic substrate layer and the etchant, guaranteeing consistent reaction throughout.

[0037] In one embodiment of this application, the immersion time of the inorganic substrate in the etchant ranges from 5s to 800s. This allows for control of the reaction degree between the etchant and the inorganic substrate, facilitating the adjustment of pore size and porosity in the micro / nano-scale porous structure. The immersion time of the etchant can be adjusted based on the reaction rate of the etchant and the desired micro / nano-scale porous structure data; for example, the immersion time of the inorganic substrate in the etchant can be any value between 5s and 800s, such as 50s, 150s, 300s, 450s, 600s, or 700s.

[0038] In one embodiment of this application, the etchant is dried by blowing, vacuum flash evaporation, natural drying, or infrared heating. This removes excess etchant, stops the etchant from penetrating the inorganic substrate, and maintains the stability of the formed micro / nano-scale porous structure.

[0039] In one embodiment of this application, the inorganic substrate layer is annealed after etching at a temperature between 50°C and 300°C for a duration between 5s and 2000s. This removes residual solvent from the etchant, maintains the stability of the micro / nano-scale porous structure, and prevents the etchant from affecting subsequent reactions. For etchant solvents with lower boiling points, a lower annealing temperature can be selected; for etchant solvents with higher boiling points, a higher annealing temperature can be used. The annealing temperature can be any temperature within the range of 50°C to 300°C, such as 80°C, 120°C, 180°C, 240°C, or 270°C. The annealing time can be selected according to the solvent and temperature, and can be any time within the range of 5s to 2000s, such as 50s, 150s, 300s, 450s, 600s, 900s, 1200s, or 1500s.

[0040] In one embodiment of this application, the inorganic substrate layer includes AX and BX2; A is a monovalent metal cation, B is a divalent metal cation, and X is a monovalent anion; A includes Cs. + and Rb + At least one of them, B includes Pb 2+ or Sn 2+ At least one of them; X includes I - ,Br - Cl - or SCN - At least one of the following. This can be understood as the inorganic substrate layer being deposited using a mixed solution of AX and BX2, where AX includes at least one of CsI, CsBr, CsCl, CsSCN, RbI, RbBr, RbCl, and RbSCN; and BX2 includes at least one of PbI2, PbBr2, PbCl2, Pb(SCN)2, SnI2, SnBr2, SnCl2, and Sn(SCN)2. This allows for the formation of a mixed-component inorganic substrate layer and helps reduce metal halide residues in the resulting perovskite.

[0041] In one embodiment of this application, the organic salt reactive ink comprises an organic salt and an organic solvent, wherein the organic salt is CY; C is a monovalent organic cation, and Y is a monovalent anion; C includes methylamine cation (MA). + ), formamidinium cation (FA) + ), phenylethylamine halide cation (PEA) + At least one of the following, Y includes iodide ions (I - ), bromide ions (Br)- ), chloride ions (Cl) - ) or thiocyanate ions (SCN) - At least one of the following: ); the organic solvent includes at least one of isopropanol, ethanol, and n-butanol.

[0042] In one embodiment of this application, please refer to Figure 1 and Figure 4 The organic salt reactive ink also includes a penetration enhancer, which includes at least one selected from ethylene glycol monomethyl ether, diphenyl sulfoxide, γ-lactone, dimethyl sulfone, N,N-dimethylformamide, and N-methylpyrrolidone. This improves the permeability of the organic salt reactive ink, which is beneficial for the uniform reaction of the porous inorganic substrate.

[0043] In one embodiment of this application, the penetration enhancer has a mass ratio of 0.1%-50%. The mass ratio can be selected based on the effect of the penetration enhancer, and can be any value between 0.1% and 50%, such as 5%, 10%, 20%, 30%, or 40%. This allows for the control of the penetration rate of the organic salt reaction ink.

[0044] In one embodiment of this application, please refer to Figure 1 In step S30, the organic salt reactive ink is applied to the porous inorganic substrate layer using inkjet printing, spin coating, or slot coating processes. This allows for control over the uniform coating of the organic salt reactive ink on the porous inorganic substrate layer, ensuring consistent penetration and reaction across different areas.

[0045] In one embodiment of this application, please refer to Figures 1 to 3 In step S30, the organic salt reaction ink is dried by blowing, vacuum flash evaporation, natural drying, or infrared heating. This allows for control of the reaction time.

[0046] In one embodiment of this application, please refer to Figure 1 In step S40, during the annealing of the pre-crystallized film: the annealing temperature is between 50℃ and 300℃, and the annealing time is between 5s and 2000s. The annealing temperature can be any temperature within the range of 50℃ to 300℃, such as 80℃, 120℃, 180℃, 240℃, or 270℃; the annealing time can be selected according to the solvent and temperature, and can be any time within the range of 5s to 2000s, such as 50s, 150s, 300s, 450s, 600s, 900s, 1200s, or 1500s. This further removes solvent residue from the organic salt reaction ink, forming a stable perovskite thin film layer.

[0047] This application also provides a battery, including a perovskite layer, which is prepared by the method in any of the above embodiments. By employing the perovskite thin film preparation methods described above, a transition layer with precisely controllable pore size, porosity, and a three-dimensional interconnected structure can be formed, thereby improving the thickness and compositional uniformity of the perovskite layer, enhancing its consistency, and improving the reliability of the battery.

[0048] The following description uses an embodiment of this application and related comparative examples.

[0049] Example 1: Please refer to Figure 5 This application provides a perovskite / crystalline silicon tandem solar cell, comprising, from bottom to top: a first metal electrode layer 211, a first transparent electrode layer 221, a silicon substrate 2, a second transparent electrode layer 222, a carrier transport layer 131, a carrier transport layer passivation layer 132, a perovskite thin film 14, a second carrier transport layer 15, a third transparent electrode layer 223, and a second metal electrode layer 212. Specific fabrication steps include: Step 1: Fabricate a first transparent electrode layer 221 on a silicon substrate 2. Optionally, using magnetron sputtering, the silicon substrate 2 is placed in a magnetron sputtering apparatus, an ITO (Indium Tin Oxide) target is set, and the power is controlled between 10W and 400W. Specifically, in Example 1, the controlled power is 85W, the running time is 0.8h, and the thickness of the first transparent electrode layer 221 is 80nm.

[0050] Step 2: Fabricate the first metal electrode layer 211 on the first transparent electrode layer 221. Optionally, using vapor deposition, place the prepared substrate sample onto a mask and place it in the vapor deposition chamber, with a vapor deposition vacuum of 1×10⁻⁶. - 5 Pa-1×10 -3 The vapor deposition temperature is between 200℃ and 2000℃, and the evaporation rate is 0.1 Å / s - 50 Å / s. Specifically, in Example 1, the vapor deposition vacuum degree is 8 × 10⁻⁶. -4 Silver was deposited onto a film with a thickness of 120 nm by adjusting the deposition voltage and evaporation temperature at Pa and controlling the evaporation rate at 1.5 Å / s.

[0051] Step 3: Fabricate a second transparent electrode layer 222 on the other side of the silicon substrate 2. Optionally, using magnetron sputtering, place the above sample in a magnetron sputtering apparatus, set an ITO (Indium Tin Oxide) target, and control the power between 10W and 400W. Specifically, in Example 1, the control power is 70W, the running time is 1 hour, and the film thickness is 40nm.

[0052] Step 4: NIOx is fabricated on the surface of the second transparent electrode layer 222 as a carrier transport layer 131 using a controlled sputtering process. In Example 1, the thickness of NIOx is 8 nm.

[0053] Step 5: Prepare the passivation layer solution for the carrier transport layer passivation layer 132. Specifically, in Example 1, Meo-2pacz was dissolved in ethanol to obtain the passivation layer solution with a concentration of 5 mg / mL.

[0054] Step 6: Apply the passivation layer solution prepared in step 5 onto the carrier transport layer 131 using a slit coating process. After annealing at 150°C for 20 minutes, the carrier transport layer passivation layer 132 is obtained.

[0055] Step 7: Deposit an inorganic substrate layer. Optionally, the inorganic substrate layer material is AX and BX2, where A is a monovalent metal cation, including but not limited to cesium ions (Cs). + ), rubidium ions (Rb + B is a divalent metal cation, including but not limited to lead ions (Pb). 2+ ), tin ions (Sn) 2+ At least one of the following: X is a monovalent anion: including but not limited to iodide ion (I2). - ), bromide ions (Br) - ), chloride ions (Cl) - ) or halide ions (SCN) - At least one of the following: inorganic substrate deposition process includes, but is not limited to, evaporation, spin coating, inkjet printing, slot coating, and other coating processes. In Example 1, the material in the perovskite inorganic substrate is a mixture of PbI2, PbBr2, and CsI in a certain proportion. The inorganic substrate deposition process uses a three-source co-evaporation process, with the evaporation rate controlled at 5 Å / s.

[0056] Step 8: Prepare an etchant and deposit it on the surface of an inorganic substrate to immerse and etch it, inducing the formation of a micro-nano-scale porous structure in the inorganic substrate. Then, remove excess etchant from the surface of the inorganic substrate through a drying process. Finally, anneal the etched inorganic substrate to reduce surface stress and stabilize its porous structure, thus obtaining a porous inorganic substrate. Optionally, the main solvent of the etchant includes, but is not limited to, volatile solvents such as isopropanol (IPA), ethanol (EtOH), and n-butanol; the etchant reaction material (i.e., solute) includes, but is not limited to, one or more of dimethyl sulfone, N,N-dimethylformamide, and N-methylpyrrolidone; the mass percentage of the etchant reaction material in its solution is 0.1% to 70%; the deposition process of the etchant on the surface of the inorganic substrate includes, but is not limited to, vapor deposition, spin coating, inkjet printing, and slot coating; the immersion time of the etchant is in the range of 5s to 800s; the drying process of the etchant includes, but is not limited to, blowing, vacuum flash evaporation, natural drying, and infrared heating; the annealing process after etching the inorganic substrate has an annealing temperature of 50 to 300℃ and an annealing time of 5 to 2000s.

[0057] Specifically, in Example 1, the main solvent of the etchant is a mixed solvent of 80% isopropanol (IPA) and 20% ethanol (EtOH), the etchant reaction material is N-methylpyrrolidone, which accounts for 3% by mass, the deposition process of the etchant on the surface of the inorganic substrate is inkjet printing, the immersion time of the etchant is 40s, the drying process is blow drying, and the annealing parameters are 70℃ and 600s.

[0058] Step 9: Prepare an organic salt reaction solution, add a penetration enhancer to obtain a highly penetrating organic salt reaction ink. Coat the organic salt reaction ink onto a porous inorganic substrate. Through the organic salt reaction ink drying process, the organic salt reactants are encouraged to penetrate into the porous inorganic substrate through the penetration enhancer within the organic salt reaction ink, forming a perovskite pre-crystallized film. Finally, the pre-crystallized film is annealed to obtain a fully reacted perovskite film 14.

[0059] Optionally, the organic salt material in the organic salt reaction solution is CX, where C is a monovalent organic cation, including but not limited to methylamine cation (MA). + ) or formamidinium cation (FA + ), phenylethylamine cation (PEA) + X is one or more cations in the group; X is a monovalent anion, including but not limited to iodide ions (I₂). - ), bromide ions (Br) - ), chloride ions (Cl) - ) or halogen-like substances (e.g., thiocyanate ions SCN) -The organic salt reaction solution contains one or more anions; the solvent of the organic salt reaction solution includes, but is not limited to, isopropanol (IPA), ethanol (EtOH), n-butanol, and other volatile solvents that will not dissolve the inorganic substrate; the penetration enhancer includes, but is not limited to, one or more of ethylene glycol monomethyl ether (2-ME), diphenyl sulfoxide (DPSO), γ-butanediol (GBL), dimethyl sulfone (DMSO), N,N-dimethylformamide (DMF), and N-methylpyrrolidone (NMP); the mass percentage of the solute in the penetration enhancer is 0.1% to 50%; the organic salt reaction ink coating process includes, but is not limited to, inkjet printing, spin coating, slot coating, and other coating processes; the organic salt reaction ink drying process includes, but is not limited to, blowing, vacuum flash evaporation, natural drying, infrared heating, and other processes; the annealing temperature of the pre-crystallized film is 50℃-300℃, and the annealing time is 5s-2000s.

[0060] Specifically, in Example 1, the organic salt material in the organic salt reaction solution was a mixture of FAI, MAI, and FABr in a certain proportion, and n-butanol was selected as the solvent to prepare an organic halogen salt solution of 15 mg / mL. The penetration enhancer was N-methylpyrrolidone (NMP), which accounted for 5% by mass. The organic salt reaction ink was coated onto the porous inorganic substrate layer using inkjet printing, and the drying process of the organic salt reaction ink was carried out by blowing air, with annealing parameters of 120°C and 800 s.

[0061] Step 10: Select C60 and SnO2 as the second carrier transport layer 15, and deposit 34nm C60 and 20nm SnO2 sequentially on the perovskite thin film 14 by vapor deposition.

[0062] Step 11: Fabricate a third transparent electrode layer 223 on the second carrier transport layer 15.

[0063] Specifically, using magnetron sputtering, transparent electrode material is sputtered onto the surface of the second carrier transport layer 15, with a controlled power of 30W-200W.

[0064] Step 12: Fabricate a second metal electrode layer 212 on the third transparent electrode layer 223. Specifically, it is similar to the fabrication of the first metal electrode layer 211, except that the mask is different and the thickness is 100 nm.

[0065] Comparative Example 1: A perovskite / crystalline silicon tandem solar cell is provided, having the same device layer structure as Example 2, comprising, from bottom to top: a first metal electrode layer 211, a first transparent electrode layer 221, a silicon substrate 2, a second transparent electrode layer 222, a carrier transport layer 131, a carrier transport layer passivation layer 132, a perovskite thin film 14, a second carrier transport layer 15, a third transparent electrode layer 223, and a second metal electrode layer 212. The difference from Example 1 is that step eight is omitted in Comparative Example 1, and a penetration enhancer is not added in step nine. That is, the inorganic substrate layer of Comparative Example 1 is not etched or modified by an etchant, and no penetration enhancer is added to the organic salt reaction solution.

[0066] Comparative Example 2: A perovskite / crystalline silicon tandem solar cell is provided, having the same device layer structure as Example 2, comprising, from bottom to top: a first metal electrode layer 211, a first transparent electrode layer 221, a silicon substrate 2, a second transparent electrode layer 222, a carrier transport layer 131, a carrier transport layer passivation layer 132, a perovskite thin film 14, a second carrier transport layer 15, a third transparent electrode layer 223, and a second metal electrode layer 212. The difference from Example 1 is that Comparative Example 2 omits step eight; that is, the inorganic substrate layer of Comparative Example 1 was not subjected to inorganic substrate etchant modification treatment.

[0067] Comparative Example 3: A perovskite / crystalline silicon tandem solar cell is provided, having the same device layer structure as Example 2, comprising, from bottom to top: a first metal electrode layer 211, a first transparent electrode layer 221, a silicon substrate 2, a second transparent electrode layer 222, a carrier transport layer 131, a carrier transport layer passivation layer 132, a perovskite thin film 14, a second carrier transport layer 15, a third transparent electrode layer 223, and a second metal electrode layer 212. The difference from Example 1 is that a penetration enhancer was not added in step nine of Comparative Example 1.

[0068] Comparative experiments were conducted on the embodiments of this application with Comparative Examples 1 to 3. The inorganic substrate layer and perovskite layer of the four examples were characterized using scanning electron microscopy (SEM), and the results are as follows: Figure 6 As shown in the table comparison, we can see that: 1. As can be seen from the comparison between Example 1 and Comparative Example 1, the inorganic substrate layer that has not been etched by an etchant has an overly dense structure, which causes the organic salt solution to accumulate on its surface, making it unable to penetrate deeply and react completely, resulting in poor crystal morphology and indistinct grains.

[0069] 2. As can be seen from the comparison between Example 1 and Comparative Example 2, forcibly coating an organic salt solution with a penetration enhancer onto an inorganic substrate that has not been etched with an etchant will severely damage its morphology and structure. The resulting perovskite film has many pinholes, is not dense enough, and has a very poor crystal structure.

[0070] 4. As can be seen from the comparison between Example 1 and Comparative Example 3, the reaction of perovskite on an inorganic substrate layer etched by an etchant using an organic salt solution without a penetration enhancer will result in poor penetration of the organic salt solution, and can only form a perovskite film with an uneven morphology on the surface of the porous inorganic substrate layer.

[0071] In comparison, Embodiment 1 of this application has a denser and more continuous perovskite film.

[0072] A comparative experiment was conducted between Example 1 of this application and Comparative Examples 1-3. A standard solar intensity calibration was performed using a solar simulator, and the calibration was performed on an area of ​​1.0 cm². 2 The comparative device was tested over a long period of time, with the starting voltage set to 0V, the cutoff voltage to 2.0V, and the range to 100mA. The test results are shown in the table below.

[0073]

[0074] A comparison of the experimental data from Example 1 and Comparative Examples 1-3 in the table above shows that: The perovskite formed by the inorganic substrate being etched and modified with an etchant and reacted with an organic salt reaction ink exhibits higher performance in perovskite / crystalline silicon tandem solar cell devices.

[0075] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing perovskite thin films, characterized in that, include: A substrate is provided, on which an inorganic substrate layer is deposited; The inorganic substrate is immersed in an etchant to etch it, thereby obtaining a porous inorganic substrate with a micro-nano-scale porous structure. An organic salt reaction ink is coated onto the porous inorganic substrate, and the organic salt reaction ink is dried to form a perovskite pre-crystallized film. The pre-crystallized film was annealed to obtain a perovskite film.

2. The method for preparing perovskite thin films according to claim 1, characterized in that, The solvent of the etchant is at least one of isopropanol, ethanol, and n-butanol; The solute of the etchant is at least one of dimethyl sulfone, N,N-dimethylformamide, and N-methylpyrrolidone.

3. The method for preparing perovskite thin films as described in claim 2, characterized in that, The mass percentage of solute in the etchant is 0.1%-70%.

4. The method for preparing perovskite thin films according to claim 1, characterized in that, The etchant is deposited on the surface of the inorganic substrate layer via vapor deposition, spin coating, inkjet printing, or slot coating processes; and / or The inorganic substrate is immersed in the etchant for a period ranging from 5 s to 800 s; and / or, The etchant is dried by air blowing, vacuum flash evaporation, natural drying, or infrared heating processes; and / or, The inorganic substrate is etched and then annealed at a temperature of 50℃-300℃ for a time of 5s-2000s.

5. The method for preparing perovskite thin films according to claim 1, characterized in that, The inorganic substrate layer includes AX and BX2; A is a monovalent metal cation, B is a divalent metal cation, and X is a monovalent anion; A includes Cs. + and Rb + At least one of them, wherein B includes Pb 2+ or Sn 2+ At least one of them; The X includes I - ,Br - Cl - or SCN - At least one of them.

6. The method for preparing perovskite thin films according to claim 1, characterized in that, The organic salt reactive ink comprises an organic salt and an organic solvent, wherein the organic salt is CY; C is a monovalent organic cation, and Y is a monovalent anion; C includes at least one of methylamine, formamidinium, and phenylethylamine halide cations, and Y includes I - ,Br - Cl - or SCN - At least one of them; The organic solvent includes at least one of isopropanol, ethanol, and n-butanol.

7. The method for preparing perovskite thin films according to claim 6, characterized in that, The organic salt reactive ink also includes a penetration enhancer, which includes at least one of ethylene glycol monomethyl ether, diphenyl sulfoxide, γ-lactone, dimethyl sulfone, N,N-dimethylformamide, and N-methylpyrrolidone.

8. The method for preparing perovskite thin films as described in claim 7, characterized in that: The penetration enhancer has a mass ratio of 0.1%-50%.

9. The method for preparing perovskite thin films according to any one of claims 1 to 8, characterized in that, The organic salt reactive ink is applied to the porous inorganic substrate layer via inkjet printing, spin coating, or slot coating processes; and / or The organic salt reactive ink is dried by air blowing, vacuum flash evaporation, natural drying, or infrared heating processes; and / or, In the step of annealing the pre-crystallized film: the annealing temperature is 50℃-300℃, and the annealing time is 5s-2000s.

10. A battery comprising a perovskite layer, characterized in that: The perovskite layer is prepared by the method described in any one of claims 1-9.

Images