Method for improving perovskite thin film quality by synergistic dopant and additive combination strategy

Abstract

The present application relates to a method for improving the quality of perovskite thin films by a synergistic dopant and additive combination strategy, belonging to the technical field of perovskite thin films, comprising: raw material preparation: preparing dopant, additive, perovskite precursor material and solvent for dissolving precursor material; precursor solution preparation: mixing dopant, additive, perovskite precursor material with solvent in proportion to prepare perovskite precursor solution; solution stirring and standing, filtering: stirring: stirring the precursor solution at room temperature to ensure that the dopant and additive are fully dissolved and uniformly distributed; standing, filtering: standing and precipitating impurities, and then filtering the solution through a filter membrane; preparing a substrate; coating of the precursor solution: uniformly coating the prepared precursor solution containing dopant, additive on the substrate; preliminary drying: after coating, placing the substrate in air for standing and drying; performing annealing treatment.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of perovskite thin films, and in particular to a method for improving the quality of perovskite thin films by a synergistic dopant and additive combination strategy. BACKGROUND

[0002] Perovskite solar cells have attracted extensive attention in recent years due to their high photoelectric conversion efficiency and low-cost fabrication process. Perovskite materials have good light absorption properties, long carrier diffusion length, and easily controllable energy band structure, making them exhibit great potential in the field of solar cells. However, the commercialization process of perovskite solar cells still faces some key challenges, especially the stability and quality of the thin films.

[0003] In the preparation process of perovskite thin films, the preparation of precursor solution and the coating process are crucial for the quality and performance of the thin films. In conventional perovskite preparation methods, the precursor solution is prone to uneven solvent evaporation speed, insufficient interaction between components, and other reasons, leading to uneven formation of perovskite crystals, which in turn affects the photoelectric performance and stability of the thin films. In addition, perovskite materials are prone to decomposition in high temperature and high humidity environments, limiting their long-term stability in practical applications. SUMMARY

[0004] In order to overcome the above-mentioned defects of the prior art, the present application provides a method for improving the quality of perovskite thin films by a synergistic dopant and additive combination strategy to solve the problems raised in the background art.

[0005] In order to achieve the above-mentioned application purposes, the present application provides a method for improving the quality of perovskite thin films by a synergistic dopant and additive combination strategy, which comprises:

[0006] Preparation of raw materials:

[0007] Prepare dopant, additive, perovskite precursor material and solvent for dissolving precursor material, wherein the dopant is methylammonium chloride, the additive is 1-ethyl-3-methylimidazolium tetrafluoroborate, the perovskite precursor material is cesium iodide, formamidinium iodide, lead iodide, and the solvent includes N-methylpyrrolidone and dimethylformamide;

[0008] Preparation of precursor solution:

[0009] Mix the 1-ethyl-3-methylimidazolium tetrafluoroborate, the methylammonium chloride, the cesium iodide, the formamidinium iodide, and the lead iodide in proportion with the solvent to prepare a perovskite precursor solution with a concentration of 1M;

[0010] Stirring and standing of the solution, filtration:

[0011] Stirring: The precursor solution containing dopants and additives is stirred at room temperature to ensure that the dopants and additives are fully dissolved and uniformly distributed;

[0012] Settling and filtration: Allow the solution to settle and precipitate impurities, then filter the solution through a filter membrane to remove undissolved particles and impurities, ensuring the purity and stability of the solution.

[0013] Base preparation:

[0014] NiO thin films were prepared by magnetic control and then annealed in air at 300°C for 30–60 minutes to improve the crystallinity and conductivity of the NiO thin films.

[0015] Precursor solution coating:

[0016] The prepared precursor solution containing methylammonium chloride and 1-ethyl-3-methylimidazolium tetrafluoroborate was uniformly coated onto the pretreated substrate;

[0017] Preliminary drying:

[0018] After coating is completed, the substrate is left to stand in the air to allow some of the solvent to evaporate, allowing the film to initially form.

[0019] Annealing treatment:

[0020] The substrate coated with the precursor solution is placed on a heating plate. After the temperature of the heating plate rises, it is maintained at that temperature for annealing to form a uniform and stable perovskite film and reduce grain boundary defects and surface roughness.

[0021] Thin film property testing and performance evaluation:

[0022] After the perovskite thin film is prepared, it is tested and evaluated.

[0023] Furthermore, the solvent is a mixture of N-methylpyrrolidone and dimethylformamide in a volume ratio of 4:1.

[0024] Furthermore, the 1-ethyl-3-methylimidazolium tetrafluoroborate is dissolved in the solvent at a ratio of 0.05M to 0.2M.

[0025] Furthermore, the precursor solution is magnetically stirred at room temperature for 2 to 4 hours.

[0026] Furthermore, in the settling and filtration steps, the solution is settling for 0.5 to 1.5 hours, and then filtered through a filter membrane with a pore size of 0.4 to 0.5 μm.

[0027] Furthermore, the coating thickness of the precursor solution is 300–600 nanometers.

[0028] Furthermore, the substrate coated with the precursor solution is placed on a heating plate, and after the temperature of the heating plate is raised to 150°C to 200°C, it is annealed at this temperature for 10 to 30 minutes.

[0029] Furthermore, the detection and evaluation of the perovskite thin film includes:

[0030] Particle size and surface smoothness: The surface of the perovskite film was observed using a scanning electron microscope to confirm that the film surface was smooth and the particle size was between 800 and 1200 nanometers.

[0031] Furthermore, the detection and evaluation of the perovskite thin film also includes:

[0032] Stability test: The prepared perovskite thin film was subjected to stability test under high temperature and high humidity environment. The photoelectric conversion efficiency of the film was recorded after one month to ensure that its photoelectric conversion efficiency remained at 90% or above of the initial efficiency.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] The combined strategy of adding 1-ethyl-3-methylimidazolium tetrafluoroborate and methylammonium chloride can effectively inhibit the degradation of PPS, form a uniform perovskite crystal structure, and improve the quality and charge transport efficiency of the film.

[0035] The photoelectric conversion efficiency of the battery is improved by 3-5%, and its stability is significantly enhanced, enabling it to maintain stable performance under high temperature and high humidity conditions. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the thin film structure before the improvement of this invention;

[0037] Figure 2 This is a schematic diagram of the improved thin film structure of the present invention. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the invention, but not all embodiments. The embodiments of the present invention are described below with reference to the accompanying drawings.

[0039] A method for improving the quality of perovskite thin films through a synergistic dopant and additive combination strategy, the method comprising the following steps:

[0040] Raw material preparation:

[0041] Prepare dopant, additive, perovskite precursor material, and solvent for dissolving the precursor material. The dopant is methylammonium chloride, the additive is 1-ethyl-3-methylimidazolium tetrafluoroborate, the perovskite precursor material is a mixture of cesium iodide, formamidinium iodide, and lead iodide, and the solvent is a mixture of N-methylpyrrolidone and dimethylformamide.

[0042] Precursor solution preparation:

[0043] The 1-ethyl-3-methylimidazolium tetrafluoroborate, the methylammonium chloride, the cesium iodide, the formamidinium iodide, and the lead iodide were mixed with the solvent in a certain proportion to prepare a 1M perovskite precursor solution.

[0044] Stirring, settling, and filtering of the solution:

[0045] Stirring: The precursor solution containing dopants and additives is stirred at room temperature to ensure that the dopants and additives are fully dissolved and uniformly distributed;

[0046] Settling and filtration: Allow the solution to settle and precipitate impurities, then filter the solution through a filter membrane to remove undissolved particles and impurities, ensuring the purity and stability of the solution.

[0047] Base preparation:

[0048] NiO thin films were prepared by magnetic control and then annealed in air at 300°C for 30–60 minutes to improve the crystallinity and conductivity of the NiO thin films.

[0049] Precursor solution coating:

[0050] The prepared precursor solution containing methylammonium chloride and 1-ethyl-3-methylimidazolium tetrafluoroborate was uniformly coated onto the pretreated substrate;

[0051] Preliminary drying:

[0052] After coating is completed, the substrate is left to stand in the air to allow some of the solvent to evaporate, allowing the film to initially form.

[0053] Annealing treatment:

[0054] The substrate coated with the precursor solution is placed on a heating plate. After the temperature of the heating plate rises, it is maintained at that temperature for annealing to form a uniform and stable perovskite film and reduce grain boundary defects and surface roughness.

[0055] Thin film property testing and performance evaluation:

[0056] After the perovskite thin film is prepared, it is tested and evaluated.

[0057] The solvent is a mixture of N-methylpyrrolidone and dimethylformamide in a volume ratio of 4:1.

[0058] The 1-ethyl-3-methylimidazolium tetrafluoroborate was dissolved in the solvent at a ratio of 0.05 M to 0.2 M.

[0059] The precursor solution was magnetically stirred at room temperature for 2–4 hours.

[0060] In the settling and filtration steps, the solution is allowed to stand for 0.5 to 1.5 hours, and then filtered through a filter membrane with a pore size of 0.4 to 0.5 μm.

[0061] The thickness of the precursor solution coating is 300–600 nanometers;

[0062] The substrate coated with the precursor solution is placed on a heating plate. After the temperature of the heating plate is raised to 150℃~200℃, it is annealed at this temperature for 10~30 minutes.

[0063] The testing and evaluation of perovskite thin films includes:

[0064] Particle size and surface smoothness: The surface of the perovskite film was observed using a scanning electron microscope to confirm that the film surface was smooth and the particle size was between 800 and 1200 nanometers.

[0065] Stability test: The prepared perovskite film was subjected to stability test under high temperature and high humidity environment. The photoelectric conversion efficiency of the film was recorded after one month to ensure that its photoelectric conversion efficiency remained at 90% or above of the initial efficiency.

[0066] In the prior art, research on improving the quality of perovskite thin films by adding dopants and additives has made some progress. For example, adding different types of dopants to the perovskite precursor solution can optimize the crystal growth process and improve the crystallinity and surface smoothness of the film. Common dopants include ammonium salts and halides. These dopants can regulate the growth rate and morphology of the crystal, thereby improving the photoelectric conversion efficiency of the film.

[0067] However, the effects of using a single dopant are limited, especially in complex crystal growth environments, where it is difficult to simultaneously achieve both perovskite crystal uniformity and film stability. To address this issue, some studies have attempted to introduce ionic liquids as additives, leveraging their unique chemical properties to stabilize the perovskite precursor solution and suppress crystal defect formation. Ionic liquids, due to their high chemical stability and good solubility, are considered a potential class of perovskite film modifiers. However, existing research has largely focused on the use of single ionic liquids, with relatively few studies on the synergistic effects of dopant and ionic liquid.

[0068] This application successfully overcomes the shortcomings of the prior art by introducing a combination of methylammonium chloride (MACl) and 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]), providing a new solution for the efficient and stable preparation of perovskite thin films;

[0069] The quality of perovskite films can be improved by combining synergistic dopants and additives. Methylammonium chloride (MACl) is used as a dopant and a Lewis basic ionic liquid, such as 1-ethyl-3-methylimidazolium tetrafluoroborate, is added as an additive. This combination can inhibit the degradation of perovskite precursor solution (PPS), inhibit the aggregation of MACl, and form a uniform and stable perovskite film.

[0070] refer to Figure 1 and Figure 2 , Figure 1 and Figure 2 The image shows a comparison of the film before and after the improvement. Figure 1 For perovskite films without the addition of MACl and [EMIM][BF4], Figure 2 For perovskite films with added dopants and additives, the improved film surface is smoother, the particles are more uniform, and the inter-particle defects are reduced, showing a significant quality improvement.

[0071] The combined strategy of adding 1-ethyl-3-methylimidazolium tetrafluoroborate and methylammonium chloride can effectively inhibit the degradation of PPS, form a uniform perovskite crystal structure, and improve the quality and charge transport efficiency of the film.

[0072] Experiments show that the photoelectric conversion efficiency of the battery is improved by 3-5%, and its stability is significantly enhanced, maintaining stable performance under high temperature and high humidity conditions.

[0073] The technical solution of the present invention has been described above in conjunction with specific embodiments. However, it should be noted that the above descriptions are only for explaining the solution of the present invention and should not be construed as a specific limitation on the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can conceive of other specific embodiments or equivalent substitutions of the present invention without creative effort, and all such embodiments or substitutions will fall within the scope of protection of the present invention.

Claims

1. A method for improving the quality of perovskite thin films through a synergistic dopant and additive combination strategy, characterized in that, The method includes: Raw material preparation: Prepare a dopant, an additive, a perovskite precursor material, and a solvent for dissolving the precursor material, wherein the dopant is methylammonium chloride, the additive is 1-ethyl-3-methylimidazolium tetrafluoroborate, the perovskite precursor material is cesium iodide, formamidinium iodide, or lead iodide, and the solvent includes N-methylpyrrolidone and dimethylformamide; Precursor solution preparation: The 1-ethyl-3-methylimidazolium tetrafluoroborate, the methylammonium chloride, the cesium iodide, the formamidinium iodide, and the lead iodide were mixed with the solvent in a certain proportion to prepare a 1 M perovskite precursor solution; Stirring, settling, and filtering of the solution: Stirring: The precursor solution containing dopants and additives is stirred at room temperature to ensure that the dopants and additives are fully dissolved and uniformly distributed; Settling and filtration: Allow the solution to settle and precipitate impurities, then filter the solution through a filter membrane to remove undissolved particles and impurities, ensuring the purity and stability of the solution. Base preparation: NiO thin films were prepared by magnetic control and then annealed in air at 300°C for 30–60 minutes to improve the crystallinity and conductivity of the NiO thin films. Precursor solution coating: The prepared precursor solution containing methylammonium chloride and 1-ethyl-3-methylimidazolium tetrafluoroborate was uniformly coated onto the pretreated substrate; Preliminary drying: After coating is completed, the substrate is left to stand in the air to allow some of the solvent to evaporate, allowing the film to initially form. Annealing treatment: The substrate coated with the precursor solution is placed on a heating plate. After the temperature of the heating plate rises, it is maintained at that temperature for annealing to form a uniform and stable perovskite film and reduce grain boundary defects and surface roughness. Thin film property testing and performance evaluation: After the perovskite thin film is prepared, it is tested and evaluated.

2. The method for improving the quality of perovskite thin films by means of a synergistic dopant and additive combination strategy according to claim 1, characterized in that, The solvent is a mixture of N-methylpyrrolidone and dimethylformamide in a volume ratio of 4:

1.

3. The method for improving the quality of perovskite thin films by means of a synergistic dopant and additive combination strategy according to claim 1, characterized in that, The 1-ethyl-3-methylimidazolium tetrafluoroborate was dissolved in the solvent at a ratio of 0.05M to 0.2M.

4. The method for improving the quality of perovskite thin films by means of a synergistic dopant and additive combination strategy according to claim 1, characterized in that, The precursor solution was magnetically stirred at room temperature for 2 to 4 hours.

5. The method for improving the quality of perovskite thin films by means of a synergistic dopant and additive combination strategy according to claim 1, characterized in that, In the filtration step, the solution is filtered through a filter membrane with a pore size of 0.4 to 0.5 μm.

6. The method for improving the quality of perovskite thin films by means of a synergistic dopant and additive combination strategy according to claim 1, characterized in that, The thickness of the precursor solution coating is 300–600 nanometers.

7. The method for improving the quality of perovskite thin films by means of a synergistic dopant and additive combination strategy according to claim 1, characterized in that, The substrate coated with the precursor solution is placed on a heating plate. After the temperature of the heating plate is raised to 150°C to 200°C, it is annealed at this temperature for 10 to 30 minutes.

8. The method for improving the quality of perovskite thin films by means of a synergistic dopant and additive combination strategy according to claim 1, characterized in that, The detection and evaluation of the perovskite thin film includes: Particle size and surface smoothness: The surface of the perovskite film was examined using a scanning electron microscope. Observation confirmed that the film surface was smooth and the particle size was between 800 and 1200 nanometers.

9. The method for improving the quality of perovskite thin films by means of a synergistic dopant and additive combination strategy according to claim 1, characterized in that, The detection and evaluation of the perovskite thin film also includes: Stability test: The prepared perovskite thin film was subjected to stability test under high temperature and high humidity environment. The photoelectric conversion efficiency of the film was recorded after one month to ensure that its photoelectric conversion efficiency remained at 90% or above of the initial efficiency.

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