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

Abstract

The invention relates to a method for improving the quality of a perovskite thin film through a synergistic dopant and additive combination strategy, and belongs to the technical field of perovskite thin films, and the method comprises the steps: preparing raw materials: preparing a dopant, an additive, a perovskite precursor material and a solvent for dissolving the precursor material; precursor solution preparation: mixing a dopant, an additive and a perovskite precursor material with a solvent in proportion to prepare a perovskite precursor solution; stirring, standing and filtering the solution: stirring the precursor solution at room temperature to ensure that the dopant and the additive are fully dissolved and uniformly distributed; standing and filtering: standing to precipitate impurities, and then filtering the solution through a filter membrane; preparing a substrate; coating of a precursor solution: uniformly coating the prepared precursor solution containing a dopant and an additive on a substrate; preliminary drying: after coating is completed, the substrate is placed in air for standing and drying; and carrying out annealing treatment.

Description

Technical Field

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

[0002] Perovskite solar cells have attracted widespread attention in recent years due to their high photoelectric conversion efficiency and low-cost preparation process. Perovskite materials have good light absorption properties, long carrier diffusion length and easily regulated band structure, which makes them show 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 their films.

[0003] In the preparation process of perovskite film, the preparation and coating process of precursor solution are crucial to the quality and performance of the film. In the conventional perovskite preparation method, the precursor solution is prone to uneven formation of perovskite crystals due to uneven solvent evaporation rate and insufficient interaction between components, which in turn affects the photoelectric performance and stability of the film. In addition, perovskite materials are prone to decomposition in high temperature and high humidity environments, limiting their long-term stability in practical applications. Summary of the invention

[0004] In order to overcome the above-mentioned defects of the prior art, the present invention 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 technology.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides a method for improving the quality of perovskite film by a synergistic dopant and additive combination strategy, the method comprising:

[0006] Raw material preparation:

[0007] 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, formamidine iodine, lead iodide, and the solvent includes N-methylpyrrolidone and dimethylformamide;

[0008] Precursor solution preparation:

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

[0010] Stirring, standing and filtering of solution:

[0011] Stirring: Stirring the precursor solution containing the dopant and the additive at room temperature to ensure that the dopant and the additive are fully dissolved and evenly distributed;

[0012] Standing and filtering: Standing to precipitate impurities, then filtering the solution through a filter membrane to remove undissolved particles and impurities to ensure the purity and stability of the solution;

[0013] Substrate preparation:

[0014] The NiO film is prepared by magnetic control and annealed in air at 300°C for 30 to 60 minutes to improve the crystal quality and conductivity of the NiO film;

[0015] Coating of precursor solution:

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

[0017] Initial drying:

[0018] After coating, the substrate is placed in the air to allow some of the solvent to evaporate and the film to form a preliminary film.

[0019] Annealing treatment:

[0020] Placing the substrate coated with the precursor solution on a heating plate, and after the temperature of the heating plate is increased, maintaining the temperature for annealing, so as to form a uniform and stable perovskite film and reduce grain boundary defects and surface roughness;

[0021] Thin film characteristics testing and performance evaluation:

[0022] After the perovskite film is prepared, the perovskite film 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 standing and filtering steps, the solution is stood 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 to 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 increased to 150° C. to 200° C., the temperature is maintained for annealing for 10 to 30 minutes.

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

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

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The combination 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 of the film and the charge transfer efficiency.

[0035] The photoelectric conversion efficiency of the battery is increased by 3-5%, and the stability is significantly enhanced, and it can maintain stable performance in high temperature and high humidity environments. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0037] Figure 2 This is a schematic diagram of the improved film structure of the present invention. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the invention, rather than all the embodiments. The embodiments of the present invention are described below in conjunction with the drawings.

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

[0040] Raw material preparation:

[0041] 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 a mixture of cesium iodide, formamidine iodine and lead iodide, and the solvent is a mixed liquid of N-methylpyrrolidone and dimethylformamide;

[0042] Precursor solution preparation:

[0043] The 1-ethyl-3-methylimidazolium tetrafluoroborate, the methylammonium chloride, the cesium iodide, the formamidine iodine, and the lead iodide are mixed with the solvent in proportion to prepare a perovskite precursor solution with a concentration of 1 M;

[0044] Stirring, standing and filtering of solution:

[0045] Stirring: Stirring the precursor solution containing the dopant and the additive at room temperature to ensure that the dopant and the additive are fully dissolved and evenly distributed;

[0046] Standing and filtering: Standing to precipitate impurities, then filtering the solution through a filter membrane to remove undissolved particles and impurities to ensure the purity and stability of the solution;

[0047] Substrate preparation:

[0048] The NiO film is prepared by magnetic control and annealed in air at 300°C for 30 to 60 minutes to improve the crystal quality and conductivity of the NiO film;

[0049] Coating of precursor solution:

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

[0051] Initial drying:

[0052] After coating, the substrate is placed in the air to allow some of the solvent to evaporate and the film to form a preliminary film.

[0053] Annealing treatment:

[0054] Placing the substrate coated with the precursor solution on a heating plate, and after the temperature of the heating plate is increased, maintaining the temperature for annealing, so as to form a uniform and stable perovskite film and reduce grain boundary defects and surface roughness;

[0055] Thin film characteristics testing and performance evaluation:

[0056] After the perovskite film is prepared, the perovskite film 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 is dissolved in the solvent at a ratio of 0.05M to 0.2M;

[0059] The precursor solution is magnetically stirred at room temperature for 2 to 4 hours;

[0060] In the step of standing and filtering, the solution is allowed to stand for 0.5 to 1.5 hours, and then filtered through a filter membrane having a pore size of 0.4 to 0.5 μm;

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

[0062] 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., the temperature is maintained for annealing for 10 to 30 minutes;

[0063] Testing and evaluation of perovskite films include:

[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 is subjected to stability test in a high temperature and high humidity environment, and the photoelectric conversion efficiency of the film is recorded after one month to ensure that its photoelectric conversion efficiency remains at or above 90% of the initial efficiency;

[0066] In the prior art, research on improving the quality of perovskite 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, halides, etc. These dopants can regulate the growth rate and morphology of the crystal, thereby improving the photoelectric conversion efficiency of the film.

[0067] However, the effect of using a single dopant is limited, especially when facing a complex crystal growth environment. It is difficult to take into account both the uniformity of the perovskite crystal and the stability of the film. To address this problem, some studies have attempted to introduce ionic liquids as additives to stabilize the perovskite precursor solution and inhibit the formation of crystal defects through their unique chemical properties. Ionic liquids are considered to be a potential class of perovskite film modifiers due to their high chemical stability and good solubility. However, existing research has mostly focused on the use of a single ionic liquid, and there is relatively little research on the synergistic effect of dopants and ionic liquids.

[0068] The present 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]), and provides a new solution for the efficient and stable preparation of perovskite films.

[0069] Improve the quality of perovskite film through the strategy of synergistic dopant and additive combination, using methylammonium chloride (MACl) as a dopant and adding a Lewis basic ionic liquid as an additive, such as 1-ethyl-3-methylimidazolium tetrafluoroborate. This combination can inhibit the degradation of perovskite precursor solution (PPS), inhibit the aggregation of MACl, and form a phase-uniform and stable perovskite film;

[0070] refer to Figure 1 and Figure 2 , Figure 1 and Figure 2 The comparison of the film before and after improvement is shown in Figure 1 For perovskite films without adding MACl and [EMIM][BF4], Figure 2 The perovskite film with dopants and additives added has a smoother surface, more uniform particles, and fewer defects between particles, showing a significant improvement in quality.

[0071] The combination 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 of the film and the charge transfer efficiency.

[0072] Experiments show that the photoelectric conversion efficiency of the battery is increased by 3-5%, the stability is significantly enhanced, and it can maintain stable performance in high temperature and high humidity environments.

[0073] The technical solution of the present invention is described above in conjunction with specific implementation methods, but it should be noted that the above descriptions are only for explaining the solution of the present invention and cannot be interpreted in any way as a specific limitation on the scope of protection of the invention. Based on the explanation here, those skilled in the art can think of other specific implementation methods or equivalent replacements of the present invention without creative work, and they will all fall within the scope of protection of the present invention.

Claims

1. A method for improving the quality of perovskite films by synergistic dopant and additive combination strategies, characterized in that: The method comprises: 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, formamidine iodine, 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 formamidine iodine, and the lead iodide are mixed with the solvent in proportion to prepare a perovskite precursor solution with a concentration of 1 M; Stirring, standing and filtering of solution: Stirring: Stirring the precursor solution containing the dopant and the additive at room temperature to ensure that the dopant and the additive are fully dissolved and evenly distributed; Standing and filtering: Standing to precipitate impurities, then filtering the solution through a filter membrane to remove undissolved particles and impurities to ensure the purity and stability of the solution; Substrate preparation: The NiO film is prepared by magnetic control and annealed in air at 300°C for 30 to 60 minutes to improve the crystal quality and conductivity of the NiO film; Coating of precursor solution: The prepared precursor solution containing methylammonium chloride and 1-ethyl-3-methylimidazolium tetrafluoroborate is uniformly coated on the pretreated substrate; Initial drying: After coating, the substrate is placed in the air to allow some of the solvent to evaporate and the film to form a preliminary film. Annealing treatment: Placing the substrate coated with the precursor solution on a heating plate, and after the temperature of the heating plate is increased, maintaining the temperature for annealing, so as to form a uniform and stable perovskite film and reduce grain boundary defects and surface roughness; Thin film characteristics testing and performance evaluation: After the perovskite film is prepared, the perovskite film is tested and evaluated.

2. The method for improving the quality of perovskite thin films by 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 synergistic dopant and additive combination strategy according to claim 1, characterized in that: The 1-ethyl-3-methylimidazolium tetrafluoroborate is 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 synergistic dopant and additive combination strategy according to claim 1, characterized in that: The precursor solution is magnetically stirred at room temperature for 2 to 4 hours.

5. The method for improving the quality of perovskite thin films by synergistic dopant and additive combination strategy according to claim 1, characterized in that: In the step of standing and filtering, 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.

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

7. The method for improving the quality of perovskite thin films by 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, and after the temperature of the heating plate is raised to 150° C. to 200° C., the temperature is maintained for annealing for 10 to 30 minutes.

8. The method for improving the quality of perovskite thin films by synergistic dopant and additive combination strategy according to claim 1, characterized in that: The detection and evaluation of the perovskite film includes: 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.

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

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