Method for preparing perovskite thin film

Abstract

The application relates to the technical field of material genetic engineering, and provides a preparation method of a perovskite film. The preparation method provided by the application comprises the following steps: providing ink, wherein the ink comprises a first perovskite donor solution and a second perovskite donor solution; ink-jet printing the first perovskite donor solution on a substrate, performing first annealing treatment, and forming a first perovskite donor film; ink-jet printing the second perovskite donor solution on the first perovskite donor film, and performing second annealing treatment. The first perovskite donor solution and the second perovskite donor solution are quantitatively deposited in steps by using an ink-jet printing process, the perovskite film synthesized is accurately controlled, the process is fully automated and has good repeatability, the preparation method is used for high-throughput screening and optimization of perovskite materials, and an effect that cannot be achieved by an existing perovskite film preparation process can be achieved.

Description

Technical Field

[0001] This application belongs to the field of materials genome engineering technology, and in particular relates to a method for preparing perovskite thin films. Background Technology

[0002] Due to their superior photoelectric properties and low-temperature solution preparation processes, perovskite materials have attracted significant attention from the global academic and industrial communities in the photovoltaic field in recent years. In photovoltaics, perovskite materials refer to semiconductor materials formed by the hybridization of metal halides and cations, with the chemical formula ABX3, where A is primarily an organic cation or an inorganic metal cation, such as methylamine CH3NH3. + Formamidin HC(NH2)2 + Cs + etc.; B is mainly composed of divalent metal cations Pb. 2+ Sn 2+ etc.; X is Cl - ,Br - I - Isohalonium anions. Perovskite materials have been widely used in various aspects of the photovoltaic field and have achieved excellent performance. Among them, the development of perovskite solar cells using perovskite materials has been rapid, with their photoelectric conversion efficiency increasing from 3.8% when they were first introduced to over 25% in just over a decade.

[0003] The key to obtaining high-efficiency photovoltaic devices lies in the preparation of perovskite thin films with high crystallinity and dense, uniform grains. Currently, perovskite thin films are mainly prepared using spin coating. However, due to inherent defects in spin coating, the films are prone to inhomogeneity when prepared over large areas, making it suitable only for small-area synthesis. Furthermore, the material utilization rate is low, and it is difficult to precisely control the proportion of each perovskite donor in the two-step deposition process, thus failing to achieve precise control over the synthesized perovskite thin film.

[0004] Perovskite materials exhibit a wide variety of compositions, including organic-inorganic hybrid lead halide perovskites, all-inorganic lead halide perovskites, low-lead and lead-free perovskites, etc. Perovskite films prepared from different materials have varying effects on improving the photoelectric efficiency of photovoltaic devices. Researching and developing perovskite materials with novel chemical compositions is an effective way to improve the photoelectric performance of materials, adjust the band gap, enhance material stability, and ultimately improve device efficiency. However, existing perovskite film preparation processes cannot achieve precise control over the synthesized perovskite films, which hinders high-throughput screening and optimization of perovskite materials and limits the standardized application of high-efficiency perovskite optoelectronic devices. Summary of the Invention

[0005] The purpose of this application is to provide a method for preparing perovskite thin films, which aims to solve the problem that existing perovskite thin film preparation processes are not conducive to high-throughput screening and optimization of perovskite materials.

[0006] The technical solution adopted in this application is as follows:

[0007] This application provides a method for preparing perovskite thin films, comprising the following steps:

[0008] An ink is provided, the ink comprising: a first perovskite donor solution and a second perovskite donor solution;

[0009] The first perovskite donor solution is inkjet printed onto a substrate and subjected to a first annealing treatment to form a first perovskite donor film.

[0010] The second perovskite donor solution is inkjet printed onto the first perovskite donor film, and then subjected to a second annealing treatment.

[0011] The perovskite thin film preparation method provided in this application employs inkjet printing technology to deposit different perovskite donor solutions onto a substrate stepwise. By utilizing inkjet printing, the method achieves stepwise quantitative deposition of the first and second perovskite donor solutions, precisely controlling the proportions of each perovskite donor used in the synthesis of the perovskite thin film. This results in the synthesis of a perovskite thin film with a specific molecular composition, enabling precise control over the synthesized perovskite thin film. The process is fully automated and exhibits excellent repeatability. Applying this preparation method to high-throughput screening and optimization of perovskite materials can achieve results unmatched by existing perovskite thin film preparation processes. The perovskite thin film prepared by this method exhibits high crystallinity, good phase uniformity, uniform grain size, and good coverage. The method is simple and easy to operate, making it suitable for the industrial preparation and application of perovskite thin films. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of a multi-channel inkjet printing system;

[0013] Figure 2 Here is a SEM image of the perovskite thin film CsPbBr3 prepared in Example 2;

[0014] Figure 3 The effective area is 0.04 cm². 2 The current density-voltage (JV) characteristic curve of the perovskite solar cell is shown, where the horizontal axis represents voltage and the current density represents current density. Detailed Implementation

[0015] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0016] This application provides a method for preparing perovskite thin films for high-throughput screening and optimization of perovskite materials. The preparation method includes the following steps:

[0017] S01. Provide ink, the ink comprising: a first perovskite donor solution and a second perovskite donor solution;

[0018] S02. The first perovskite donor solution is inkjet printed onto the substrate and subjected to a first annealing treatment to form a first perovskite donor film.

[0019] S03. The second perovskite donor solution is inkjet printed onto the first perovskite donor film, and then subjected to a second annealing treatment.

[0020] Unlike existing methods for preparing perovskite thin films using spin coating or blade coating, this application employs inkjet printing to deposit different perovskite donor solutions onto a substrate stepwise. By utilizing inkjet printing, the first and second perovskite donor solutions are quantitatively deposited stepwise, allowing precise control of the proportions of each perovskite donor used in the synthesis of the perovskite thin film. This results in the synthesis of perovskite thin films with specific molecular compositions, enabling precise control over the synthesized perovskite thin films. The process is fully automated and exhibits excellent repeatability. Applying this method to high-throughput screening and optimization of perovskite materials can achieve results unmatched by existing perovskite thin film preparation processes. The method is simple, easy to operate, and suitable for the industrial preparation and application of perovskite thin films.

[0021] Specifically, in step S01, the first perovskite donor solution is a solution containing a first perovskite donor, and the second perovskite donor solution is a solution containing a second perovskite donor. Both the first and second perovskite donors are substrates for synthesizing perovskite films, and perovskite films are synthesized through the interaction between the first and second perovskite donors.

[0022] It is understood that the composition of the first perovskite donor solution and the second perovskite donor solution in the embodiments of this application corresponds to the specific perovskite thin film to be prepared.

[0023] In some embodiments, the first perovskite donor solution is a BX2 solution, and the second perovskite donor solution is an AX solution, wherein B is a divalent metal cation, A is a monovalent metal cation, and X is a Cl- cation. - ,Br - I - SCN - Or Ac -At least one of the following. This ensures that the subsequently synthesized perovskite film is an all-inorganic perovskite film. Since all-inorganic perovskite materials have low solubility in solution, first forming BX2 and AX solutions, and then sequentially performing inkjet printing on the substrate, helps to increase the concentration of the printing material in the ink, thereby improving the synthesis efficiency of the all-inorganic perovskite film and, to some extent, improving the film quality.

[0024] Based on the previous embodiment, this application further optimizes and adjusts the concentration of BX2 in the first perovskite donor solution and the concentration of AX in the second perovskite donor solution. Under the condition of certain inkjet printing parameters, the control precision of synthesizing perovskite films can be further improved. In some embodiments, the concentration of BX2 in the first perovskite donor solution is 0.01-1.5 mol / L, and the concentration of AX in the second perovskite donor solution is 0.01-1.5 mol / L.

[0025] The solvent used to dissolve BX2 in the first perovskite donor solution may be a conventional solvent in the art. In some embodiments, the solvent of the first perovskite donor solution is selected from at least one of dimethylamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), and γ-butyrolactone (GBL).

[0026] The solvent used to dissolve AX in the second perovskite donor solution can be a conventional solvent in the art. In some embodiments, the solvent of the second perovskite donor solution is selected from at least one of methanol, ethanol, isopropanol, cyclohexane, and water.

[0027] In step S02, the first perovskite donor solution is inkjet printed onto the substrate and subjected to a first annealing treatment to form a first perovskite donor film.

[0028] The first perovskite donor solution is inkjet printed onto the substrate so that the first perovskite donor solution can form a wet film on the substrate.

[0029] The substrate, serving as a carrier for forming the perovskite thin film, can be selected from conventional materials in the art, ensuring that the substrate is inert to both the first and second perovskite donor solutions and does not affect the formation of the perovskite thin film. In some embodiments, the material forming the substrate is selected from at least one of glass, ITO, FTO, PET, Meso-TiO2, PETDOT:PSS, NiO2, and SnO2.

[0030] To achieve high-throughput inkjet printing of perovskite thin films in a short time, a multi-channel inkjet printing system is used. For example... Figure 1As shown, the multi-channel inkjet printing system consists of an ink tank, an ink tank pressure controller, a piezoelectric signal source, piezoelectric nozzles, a temperature controller, a droplet observation microscope, and a computer. The ink tank includes multiple channels, each corresponding to a specific perovskite donor solution. Multiple perovskite donor solutions are printed onto the substrate through their respective piezoelectric nozzles, allowing them to be sequentially printed onto the same glass substrate. By controlling the printing points of each nozzle, a mixed perovskite thin film is formed. The method provided in this application, based on the precise control of the synthesized perovskite thin film achieved through inkjet printing, accelerates high-throughput screening and optimization of perovskite materials by utilizing a multi-channel inkjet printing system, thus promoting the application of perovskite solar cells.

[0031] In some embodiments, inkjet printing employs a multi-channel inkjet printing system, and the above-described preparation method further includes:

[0032] Before the step of inkjet printing the first perovskite donor solution onto the substrate, the first perovskite donor solution and the second perovskite donor solution are injected into different channels of the ink pool of the multi-channel inkjet printing system, respectively.

[0033] Based on the previous embodiment, this application embodiment further adjusts the inkjet printing process conditions, such as droplet volume, droplet spacing, droplet flight speed, printing line spacing, print head flight speed, print head temperature, substrate temperature, and signal frequency, to further improve the printing accuracy of the synthesized perovskite thin film and ensure the repeatability of the printing results.

[0034] In some embodiments, the droplet volume of inkjet printing is 60-120 pL, the droplet spacing is 10-350 μm, the line spacing is 10-350 μm, the droplet velocity is 0.5-2.5 m / s, and the nozzle velocity is 5-15 mm / s. This ensures the repeatability of the printing results and enables precise printing of perovskite films with specific molecular compositions. Controlling the droplet volume within 60-120 pL ensures that the multi-channel inkjet printing system, such as a piezoelectric inkjet printer, can stably spray droplets within a specific volume range. The droplet spacing represents the distance between two droplets in the printing plane; a smaller spacing indicates a greater number of deposited droplets. By adjusting the droplet spacing to 10-350 μm, and in conjunction with the aforementioned droplet volume and the concentration of the first perovskite donor solution, high-precision control of the synthesized perovskite film is achieved. The droplet velocity affects the interaction between adjacent droplets; a droplet velocity less than 0... Droplets with a velocity of 0.5 m / s are not stable enough. Droplet velocities greater than 2.5 m / s cause excessively intense collisions on the substrate, affecting the uniformity of the perovskite film. The printing line spacing depends on the width of a single spray line; a smaller line spacing results in more deposited ink and higher film density. Under the condition that droplet volume, droplet spacing, droplet velocity, and printhead velocity are controlled within the aforementioned ranges, adjusting the printing line spacing to 10-350 μm achieves rapid printing of the film while maintaining appropriate thickness and density. In a further embodiment, the printhead temperature is 20℃-125℃, and the substrate temperature is 20℃-150℃. A suitable printhead temperature helps ensure droplet stability during printing, while a suitable substrate temperature accelerates solvent evaporation, reduces droplet diffusion on the substrate, and improves the uniformity of the printed film, thus further improving the repeatability of the printing results. Furthermore, the preferred inkjet printing signal frequency is 300-500 Hz. The signal frequency is positively correlated with the number of dots sprayed per second by the printhead. However, when the signal frequency is greater than 500Hz, it can easily lead to a decrease in droplet stability. The optimal signal frequency for controlling inkjet printing is 300-500Hz to ensure the best overall performance of inkjet printing.

[0035] A first annealing treatment is performed to remove the solvent from the wet film of the first perovskite donor solution formed on the substrate, thereby forming a first perovskite donor film in a dry film state. In some embodiments, the first annealing treatment includes annealing at 50°C-100°C for 5-120 minutes in an inert gas atmosphere and / or in air with a relative humidity of less than 40%. Annealing in an inert gas atmosphere and / or in air with a relative humidity of less than 40% prevents the formed film from reacting and decomposing with water due to excessively high air humidity. Controlling the air humidity to less than 40% is beneficial for forming films with large grain sizes. Furthermore, annealing at 50°C-450°C for 5-30 minutes ensures that the formed perovskite film has good crystallinity and a low number of film defect states.

[0036] In step S03, the second perovskite donor solution is inkjet printed onto the first perovskite donor film, and then subjected to a second annealing treatment.

[0037] The second perovskite donor solution is inkjet printed onto the first perovskite donor film, so that the second perovskite donor solution covers the first perovskite donor film and penetrates into the interior and bottom of the first perovskite donor, thereby causing the first perovskite donor and the second perovskite donor to react to form a perovskite material.

[0038] In the step of inkjet printing the second perovskite donor solution onto the first perovskite donor film, the process is the same as in step S02, and a multi-channel inkjet printing system is used. In some embodiments, the droplet volume of the inkjet print is 60-120 pL, the droplet spacing is 10-350 μm, the droplet flight speed is 0.5-2.5 m / s, the printhead flight speed is 5-15 mm / s, and the print line spacing is 10-350 μm. In further embodiments, the signal frequency of the inkjet print is preferably 300-500 Hz.

[0039] A second annealing treatment is performed to remove the solvent introduced by the second perovskite donor solution and to promote the formation of a high-quality perovskite film with a uniform and pure crystal phase. In some embodiments, the second annealing step includes annealing at 50°C-450°C for 5-30 minutes in an inert gas atmosphere and / or in air with a relative humidity of less than 40%. Annealing in an inert gas atmosphere and / or in air with a relative humidity of less than 40% prevents the formed film from reacting and decomposing with water due to excessively high air humidity. Controlling the air humidity to less than 40% is beneficial for forming films with large grain sizes. Based on this, annealing at 50°C-450°C for 5-30 minutes ensures that the formed perovskite film has good crystallinity and a low number of film defect states.

[0040] Based on the above embodiments, this application embodiment selects specific first perovskite donor solutions and second perovskite donor solutions to synthesize perovskite films with specific molecular compositions, thereby achieving precise control over the synthesized perovskite films.

[0041] In some embodiments, the BX2 solution is a PbBr2 solution, the AX solution is a CsBr solution, and the film formed after the second annealing treatment is a CsPb2Br5 film. In a further embodiment, the above preparation method further includes: inkjet printing the second perovskite donor solution onto the CsPb2Br5 film, holding it at 45℃-120℃ for 1-20 minutes, and then annealing it at 50℃-450℃ for 5-30 minutes to form a CsPbBr3 film. In an even further embodiment, the above preparation method further includes: inkjet printing the second perovskite donor solution onto the CsPbBr3 film, holding it at 45℃-120℃ for 1-20 minutes, and then annealing it at 50℃-450℃ for 5-30 minutes to form a Cs4PbBr6 film.

[0042] Based on the above embodiments, the preparation method provided in the embodiments of this application can also be used to synthesize mixed perovskite thin films in high throughput.

[0043] In some embodiments, the ink further includes a third perovskite donor solution and a fourth perovskite donor solution. The preparation method further includes, after the second annealing step, inkjet printing the third and fourth perovskite donor solutions onto a substrate to synthesize a mixed perovskite film at high throughput. The order in which the third and fourth perovskite donor solutions are printed onto the substrate can be determined by the specific perovskite film to be prepared. The third perovskite donor solution can be deposited onto the substrate to form a third perovskite donor film, and then the fourth perovskite donor solution can be printed onto the third perovskite donor film. Furthermore, the types of the third and fourth perovskite donor solutions can be determined by the specific perovskite film to be prepared, including but not limited to AX solutions and BX2.

[0044] In some embodiments, the ink further includes a first perovskite precursor solution and a second perovskite precursor solution. The preparation method further includes: after performing a second annealing treatment, inkjet printing the first perovskite precursor solution and the second perovskite precursor solution onto a substrate to synthesize a mixed perovskite film at high throughput. The first perovskite precursor solution is a solution containing a first perovskite precursor; inkjet printing the first perovskite precursor solution onto a substrate and annealing it forms the corresponding perovskite film. The second perovskite precursor solution is a solution containing a second perovskite precursor; inkjet printing the second perovskite precursor solution onto a substrate and annealing it forms the corresponding perovskite film. Furthermore, the order in which the first perovskite precursor solution and the second perovskite precursor solution are inkjet printed onto the substrate can be determined by referring to the specific perovskite thin film to be prepared. The first perovskite precursor solution and the second perovskite precursor solution can be inkjet printed onto different areas of the substrate, such as adjacent areas. Alternatively, the second perovskite precursor solution can be printed onto the thin film after the first perovskite precursor solution has been formed on the substrate, or the first perovskite precursor solution can be printed onto the thin film after the second perovskite precursor solution has been formed on the substrate.

[0045] In summary, this application embodiment achieves automated, stepwise, and quantitative deposition of different perovskite donor solutions by employing a multi-channel inkjet printing system to inkjet print different perovskite donor solutions onto a substrate. By controlling the inkjet printing parameters within the aforementioned optimized range and adjusting the concentration of the perovskite donor solutions, precise control over the ratio of the first and second perovskite donors is achieved, resulting in the synthesis of perovskite films with specific molecular compositions. This allows for precise manipulation of the synthesized perovskite films. Furthermore, this method is fully automated and exhibits excellent repeatability. Applying this preparation method to high-throughput screening and optimization of perovskite materials can achieve results unmatched by existing perovskite film preparation processes. The perovskite films prepared by the above method possess characteristics of high crystallinity, good phase uniformity, uniform grain size, and good coverage. The method is simple and easy to operate, making it suitable for the industrial preparation and application of perovskite films.

[0046] The following examples illustrate the implementation of the present invention.

[0047] Example 1

[0048] This embodiment prepares a perovskite thin film CsPb2Br5, specifically including the following steps:

[0049] (1) Prepare printing ink

[0050] PbBr2 was added to a mixed solvent of DMF and DMSO (the volume ratio of DMF to DMSO was 4:1), heated and stirred at 60°C for 2 hours, allowed to stand and age for 12 hours, and filtered to obtain a PbBr2 solution with a concentration of 0.6 M.

[0051] CsBr was added to methanol and stirred at room temperature for 2 hours. The mixture was then filtered to obtain a CsBr solution with a concentration of 0.15 M.

[0052] (2) Preparation of perovskite thin films CsPb2Br5

[0053] 1) Inject PbBr2 solution and CsBr solution into different channels of the ink pool of the piezoelectric inkjet printer.

[0054] 2) Preparation of PbBr2 thin films

[0055] Adjust the inkjet printing parameters as follows: printhead-substrate distance is 1mm, substrate selection is meso-TiO2, printhead movement speed is 10mm / s, droplet spacing is 150μm, line spacing is 150μm, substrate temperature is controlled at 60℃, printhead temperature is controlled at 40℃, signal frequency is 300Hz, perovskite droplet size is 100pL, and droplet flight speed is 1.4m / s.

[0056] Then, the PbBr2 solution was inkjet printed onto the substrate and annealed in air at 80°C for 60 min to form a PbBr2 film.

[0057] 3) Preparation of CsPb2Br5 thin films

[0058] Adjust the inkjet printing parameters as follows: the distance between the printhead and the substrate is 1 mm, the printhead moving speed is 10 mm / s, the droplet spacing is 75 μm, the line spacing is 150 μm, neither the substrate nor the printhead is heated, the signal frequency is 300 Hz, the perovskite droplet size is 100 pL, and the droplet flight speed is 1.4 m / s.

[0059] Then, the CsBr solution was inkjet printed onto the PbBr2 film, and annealed at 250°C for 8 min in air with a relative humidity of less than 40% to form a CsPb2Br5 film.

[0060] The chemical reaction involved in this embodiment includes: 2PbBr2 + CsBr → CsPb2Br5.

[0061] Example 2

[0062] In this embodiment, a perovskite thin film CsPbBr3 was prepared. The difference from Example 1 is that after step (2), the CsBr solution was inkjet printed onto the CsPb2Br5 film, kept at 85°C for 5 min, and then annealed at 250°C for 10 min in air with a relative humidity of less than 40% to form a CsPbBr3 film.

[0063] The chemical reaction involved in this embodiment includes: CsPb2Br5 + CsBr → 2CsPbBr3.

[0064] Example 3

[0065] This embodiment prepared a perovskite thin film Cs4PbBr6, which differs from Example 2 in that: after forming a CsPbBr3 thin film, a CsBr solution was inkjet printed onto the CsPbBr3 thin film, held at 85°C for 5 min, and then annealed in air at 250°C for 5 min to form a Cs4PbBr6 thin film.

[0066] The chemical reaction involved in this embodiment includes: CsPbBr3 + 3CsBr → Cs4PbBr6.

[0067] Comparative Example 1

[0068] This comparative example prepared a perovskite thin film, which differs from Example 2 in that: inkjet printing was replaced by spin coating, PbBr2 solution was spin-coated onto the substrate, and PbBr2 thin film was formed after annealing; then, CsBr solution was spin-coated onto the PbBr2 thin film, and CsBr solution was spin-coated onto the annealed thin film after annealing.

[0069] 1. The surface morphology of the perovskite thin film CsPbBr3 prepared in Example 2 was observed using a scanning electron microscope (SEM). For example... Figure 2 As shown, the perovskite thin film CsPbBr3 prepared in this embodiment has high crystallinity, uniform grain size, and a smooth and dense surface.

[0070] 2. The perovskite thin film CsPbBr3 prepared in Example 2 and the perovskite thin film prepared in Comparative Example 1 were used as the absorber layers of the perovskite solar cell, and a layer of carbon paste was brushed onto the absorber layer. Then, the layers were annealed at 95°C for 20 min to obtain an all-inorganic carbon-based perovskite solar cell.

[0071] The performance of the above-mentioned all-inorganic carbon-based perovskite solar cells was tested. Figure 3 The effective area is 0.04 cm². 2The current density-voltage (JV) characteristic curve of the perovskite solar cell was obtained. Calculations showed that the power conversion efficiency (PCE) of the perovskite solar cell formed from the perovskite thin film prepared in Example 2 was 8.37%, and the short-circuit current (JV) was... SC The value is 7.13 mA / cm. 2 Open circuit voltage (V) OC The voltage was 1.49V, and the fill factor (FF) was 78.8%. The perovskite solar cell formed from the perovskite thin film prepared in Comparative Example 1 had a power conversion efficiency (PCE) of 4.63% and a short-circuit current (J / L). SC The value is 7.47 mA / cm. 2 Open circuit voltage (V) OC The voltage is 1.12V and the fill factor (FF) is 55.2%. Clearly, the perovskite solar cell fabricated using the perovskite thin film prepared in this embodiment exhibits good cell efficiency.

[0072] 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 a perovskite thin film, characterized in that, The preparation method for high-throughput screening and optimization of perovskite materials includes the following steps: An ink is provided, the ink comprising: a first perovskite donor solution and a second perovskite donor solution; The first perovskite donor solution is inkjet printed onto a substrate and subjected to a first annealing treatment to form a first perovskite donor film. The second perovskite donor solution is inkjet printed onto the first perovskite donor film, and then subjected to a second annealing treatment. The inkjet printing employs a multi-channel inkjet printing system. Before the step of inkjet printing the first perovskite donor solution onto the substrate, the first perovskite donor solution and the second perovskite donor solution are respectively injected into different channels of the ink pool of the multi-channel inkjet printing system. The inkjet printer has a droplet volume of 60-120 pL, a droplet flight speed of 0.5-2.5 m / s, a droplet spacing of 10-350 μm, a print line spacing of 10-350 μm, and a print head flight speed of 5-15 mm / s.

2. The preparation method according to claim 1, characterized in that, The first perovskite donor solution is a BX2 solution, and the second perovskite donor solution is an AX solution, wherein B is a divalent metal cation, A is a monovalent metal cation, and X is a Cl- cation. - ,Br - I - SCN - Or Ac - At least one of them.

3. The preparation method according to claim 2, characterized in that, The concentration of BX2 in the first perovskite donor solution is 0.01-1.5 mol / L; and / or The concentration of AX in the second perovskite donor solution is 0.01-1.5 mol / L.

4. The preparation method according to claim 2, characterized in that, The first annealing process includes: annealing at 50°C-100°C for 5-120 minutes in an inert gas atmosphere and / or in air with a relative humidity of less than 40%; and / or The second annealing process includes annealing at 50°C-450°C for 5-30 minutes in an inert gas atmosphere and / or in air with a relative humidity of less than 40%.

5. The preparation method according to claim 2, characterized in that, The BX2 solution is a PbBr2 solution, the AX solution is a CsBr solution, and the film formed after the second annealing treatment is a CsPb2Br5 film.

6. The preparation method according to claim 5, characterized in that, The preparation method further includes: inkjet printing the second perovskite donor solution onto the CsPb2Br5 film, holding it at 45℃-120℃ for 1-20 minutes, and then annealing it at 50℃-450℃ for 5-30 minutes to form a CsPbBr3 film.

7. The preparation method according to claim 6, characterized in that, The preparation method further includes: inkjet printing the second perovskite donor solution onto the CsPbBr3 film, holding it at 45℃-120℃ for 1-20 minutes, and then annealing it at 50℃-450℃ for 5-30 minutes to form a Cs4PbBr6 film.

8. The preparation method according to claim 1, characterized in that, The ink further includes a third perovskite donor solution and a fourth perovskite donor solution. The preparation method further includes: after performing a second annealing treatment, inkjet printing the third perovskite donor solution and the fourth perovskite donor solution onto the substrate to synthesize a mixed perovskite film at high throughput; or The ink further includes a first perovskite precursor solution and a second perovskite precursor solution. The preparation method further includes: after performing a second annealing treatment, inkjet printing the first perovskite precursor solution and the second perovskite precursor solution onto the substrate to synthesize a mixed perovskite film in high throughput.

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