Method for improving stability of metal halide perovskite and product and application thereof

Abstract

The invention discloses a method for improving stability of metal halide perovskite and a product and application thereof, and belongs to the technical field of semiconductor photoelectric devices.The method comprises the steps that perfluoroalkyl substituted diamine cations are doped at the A site of metal halide perovskite ABX3, the chemical general formula of the perfluoroalkyl substituted diamine cations is (NH3 +) 2 (CF2) n, and the molar ratio of the doped perfluoroalkyl substituted diamine cation to the B-site cation is (0.001-0.01): 1. The perfluoroalkyl-substituted diamine cation realizes substitution doping of halide perovskite by substituting part of monovalent A-site cations in the perovskite crystal growth process, and the high charge number of the perfluoroalkyl-substituted diamine cation can form stronger electrostatic interaction with easy-to-move halogen anions in the perovskite, so that the migration difficulty of the halogen anions is increased. The method disclosed by the invention provides an important strategy for preparing an efficient and stable perovskite photoelectric device.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor optoelectronic devices, and in particular to a method for improving the stability of metal halide perovskite, and a product and application thereof. Background Art

[0002] In recent years, metal halide perovskite solar cells have become a key component of emerging photovoltaic technologies, thanks to their excellent optoelectronic properties, simple fabrication process, and inherently low material costs. Tandem cells, in particular, have attracted widespread attention due to their improved utilization of the solar spectrum and their potential to surpass the theoretical efficiency limits of single-junction cells. In these devices, wide-bandgap perovskite materials often serve as the absorber layer of the top cell, with their bandgap being manipulated primarily by varying the halogen composition or introducing different A-site cations.

[0003] However, this very bandgap engineering presents a significant challenge to material stability. Compared to traditional narrow-bandgap perovskite materials, wide-bandgap perovskite materials (such as Br-enriched or FA / Cs mixed systems) are more susceptible to photoinduced phase separation, ion migration, and crystal structure distortion, which seriously affect device stability under prolonged illumination, thermal stress, and electric fields. Furthermore, their weak thermodynamic driving force and narrow phase stability range make these materials more susceptible to degradation and significant performance degradation in practical applications.

[0004] Therefore, solving the instability of the structure, composition and interface of wide bandgap perovskite materials is the key to promoting the large-scale application of high-efficiency perovskite tandem cells, and is also one of the hot research directions. At present, there are many studies dedicated to improving the thermal, optical and electrical stability of metal halide perovskite materials. Among them, the Chinese patent document with publication number CN119462732A proposes to dope the A position with methylenediamine cation (CH2(NH3)2 2+ ,MDA 2+ ) to enhance lattice stability, this strategy can effectively inhibit ion migration and photoinduced phase separation. However, due to the high polarity and lack of hydrophobicity of this type of small-sized diamine cations, their stability in humid environments is limited, and their interference with the perovskite crystallization process may lead to unstable film quality, thereby affecting device performance. The Chinese patent document with publication number CN115942757A uses large-volume organic cations to construct low-dimensional perovskites for three-dimensional perovskite surface passivation to improve environmental stability. Although this strategy can form a protective layer to resist oxygen and moisture erosion and improve defect passivation efficiency, due to the mismatch of low-dimensional perovskite energy levels and low charge migration rate, it may cause carrier accumulation and interface recombination problems, thereby limiting device efficiency. In addition, the phase stability of low-dimensional structures during long-term device operation is also controversial. Summary of the Invention

[0005] In order to address the deficiencies in the above-mentioned prior art, the present invention provides a method for improving the stability of metal halide perovskites, which not only improves the photoelectric conversion efficiency of wide-bandgap perovskites, but also greatly suppresses the phase separation phenomenon during device operation and improves the wet-heat stability of the device.

[0006] The specific technical solutions adopted are as follows:

[0007] A method for improving the stability of metal halide perovskite, comprising doping a perfluoroalkyl-substituted diamine cation at the A position of the metal halide perovskite ABX3, wherein the chemical formula of the perfluoroalkyl-substituted diamine cation is (NH3 + )2(CF2) n (abbreviated as F-DA 2+ ), wherein n is selected from an integer of 1-4, and the molar ratio of the doped perfluoroalkyl-substituted diamine cation to the B-site cation is 0.001-0.01:1.

[0008] This invention introduces a class of perfluorinated diamine cations as auxiliary dopants at the A-site to construct a highly stable perovskite structure. The perfluorinated substituents not only significantly enhance the hydrophobicity of the cations, thereby enhancing the material's moisture resistance, but also their unique electronic properties can modulate the lattice charge distribution, further inhibiting ion migration. Furthermore, the moderate molecular rigidity and size of these diamine cations facilitate the introduction of synergistic structural stability without disrupting the three-dimensional perovskite framework, thus avoiding the charge blocking issues induced by low-dimensional structures.

[0009] The technical solution of the present invention not only improves the moisture resistance, heat resistance and light stability of perovskite materials, but also takes into account the carrier transport efficiency and film quality control, providing a new and feasible material design solution for constructing high-efficiency, long-term stable single-junction and stacked perovskite photovoltaic devices.

[0010] Furthermore, in the metal halide perovskite ABX3, the A-site cation is CH3NH3 + (MA + )、CH(NH2)2 + (FA + ), cesium ions (Cs + ), rubidium ions (Rb + ) at least one of which the B-site cation is a lead ion (Pb 2+ ), tin ions (Sn 2+ ), the anion at position X is an iodide ion (I - ), bromide ion (Br - ), chloride ion (Cl - ) at least one of.

[0011] Preferably, the method of doping a perfluoroalkyl-substituted diamine cation at the A position of the metal halide perovskite ABX3 includes: preparing a perovskite precursor solution using a perfluoroalkyl-substituted diamine cation salt, a perovskite precursor material AX, a perovskite precursor material BX2 and a solvent as raw materials, forming a film using the perovskite precursor solution, and achieving doping of the perfluoroalkyl-substituted diamine cation at the A position after annealing.

[0012] Further, the perfluoroalkyl-substituted diamine cationic salt includes at least one of perfluoroalkyl-substituted diamine dihydrochloride (F-DACl2), perfluoroalkyl-substituted diamine dibromide (F-DABr2), perfluoroalkyl-substituted diamine diiodide (F-DAI2), perfluoroalkyl-substituted diamine dithiocyanate (F-DA(SCN)2), perfluoroalkyl-substituted diamine diformate (F-DA(HCOO)2), perfluoroalkyl-substituted diamine diacetate (F-DA(CH3COO)2), perfluoroalkyl-substituted diamine oxalate (F-DA(C2O4)), perfluoroalkyl-substituted diamine dibenzoate, and perfluoroalkyl-substituted diamine diparatoluate.

[0013] Furthermore, the solvent is at least one of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), γ-butyrolactone (GBL), N-methylpyrrolidone (NMP), 2-methoxyethanol (2-ME), and isopropyl alcohol (IPA).

[0014] Preferably, the perovskite precursor solution is prepared by using a molar ratio of the perfluoroalkyl-substituted diamine cation salt, the perovskite precursor material AX, and the perovskite precursor material BX2 of 0.001-0.01:0.95-1:1 (more preferably 0.002-0.006:0.98-1:1).

[0015] Specifically, a perfluoroalkyl-substituted diamine cation salt, a perovskite precursor material AX, and a perovskite precursor material BX2 are added to a solvent, stirred or shaken until fully dissolved to obtain a perovskite precursor solution. Correspondingly, the total concentration of the perovskite precursor solution is 1.0 to 2.0 mol / L, preferably 1.2 to 1.7 mol / L.

[0016] Specifically, the film forming method includes spin coating, doctor blade coating, slit coating, vapor deposition combined with solution deposition, inkjet printing or screen printing, and the spin coating method includes a one-step spin coating method or a two-step spin coating method.

[0017] Specifically, the annealing temperature is 90-200° C., more preferably 100-120° C., and the annealing time is 5-60 minutes, more preferably 15-30 minutes.

[0018] Preferably, the thickness of the metal halide perovskite film doped with perfluoroalkyl-substituted diamine cations at the A position obtained after annealing is 400-1500 nanometers, preferably 500-1000 nanometers.

[0019] The present invention also provides a doped metal halide perovskite material, which is prepared by the method for improving the stability of metal halide perovskite.

[0020] The present invention also provides the use of the doped metal halide perovskite material in a photoelectric device.

[0021] Furthermore, the optoelectronic device is a solar cell based on the doped metal halide perovskite material, and the doped metal halide perovskite material is in the form of a thin film.

[0022] Furthermore, the solar cell includes a cell substrate, a hole transport layer (or electron transport layer), a doped metal halide perovskite material thin film active layer, an electron transport layer (or hole transport layer), a top electrode or a back electrode stacked in sequence.

[0023] Furthermore, the battery substrate includes a transparent conductive flexible substrate, a transparent conductive glass substrate, a silicon-based solar cell, a CIGS solar cell, a narrow-bandgap perovskite solar cell, an organic solar cell, etc.

[0024] Furthermore, the hole transport layer is at least one of a conjugated organic small molecule containing a phosphoric acid group, nickel oxide, CuSCN, CuI, CuS, molybdenum oxide, copper phthalocyanine, copper-nickel composite oxide, a polymer of 3-hexylthiophene (P3HT), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), and poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS).

[0025] Furthermore, the active layer of the doped metal halide perovskite material film is passivated, and the passivating agent is selected from trifluoromethylphenylethylamine iodate, ethylenediamine hydroiodide or propylenediamine hydroiodide.

[0026] Furthermore, the electron transport layer includes at least one of C60, PCBM, SnO2, TiO2, ZnO, SrTiO3, and BaSnO3.

[0027] Furthermore, the back electrode or top electrode includes at least one of gold, silver, copper, carbon, fluorine-doped tin oxide (FTO), tin-doped indium oxide (ITO), aluminum-doped zinc oxide (AZO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), cerium oxide-doped indium oxide (ICO), and gallium and aluminum co-doped zinc oxide (GAZO).

[0028] Compared with the prior art, the present application has the beneficial effects that:

[0029] (1) At the level of chemical structure, the present application uses perfluoroalkyl-substituted diamine cations for A-site doping, which has a high degree of symmetry and strong hydrophobicity in the molecular structure. Compared with traditional small-molecule diamine cations such as MDA 2+ , the present application not only performs excellently in chemical inertness, but also effectively blocks the penetration of water and oxygen, reducing the erosion of the perovskite lattice by the external environment. At the same time, the electronegativity of fluorine atoms endows the molecule with higher electronic stability, which helps to inhibit the decomposition process and fundamentally improves the environmental and light stability of perovskite materials.

[0030] (2) In terms of crystal structure and crystallization control, perfluoroalkyl-substituted diamine cations can more effectively embed in the perovskite A-site due to their rigid chain structure and steric hindrance, reducing lattice distortion and defect state density. Compared with flexible small-molecule cations such as MDA 2+ , the doping cations of the present application can promote the formation of more dense and ordered crystalline orientation of perovskite during crystallization, thereby improving the uniformity of film morphology and phase purity, and avoiding the risk of low-dimensional phase generation caused by excessive doping.

[0031] (3) In terms of device application and process compatibility, perfluoroalkyl-substituted diamine cations have good solution processing stability and compatibility with perovskite precursor systems, which are suitable for various preparation processes such as spin coating, blade coating, and spray coating, and are convenient for expansion to large-area device manufacturing. At the same time, the molecular structure of the present application does not significantly interfere with the energy level structure of perovskite, which is conducive to maintaining efficient charge transport paths and avoiding energy level shift or carrier recombination caused by cation doping, thereby helping to achieve high efficiency and high stability of photovoltaic device performance. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a schematic diagram of the structure of a perovskite solar cell based on the thin film of Example 1 and Example 2;

[0033] Figure 2 is a comparison chart of J-V curves of solar cells prepared based on the thin films of Example 1 and Comparative Example 1 in the application example;

[0034] Figure 3 is an EQE curve of a wide-bandgap perovskite solar cell prepared based on the thin film of Example 2 in the application example;

[0035] Figure 4 is a comparison chart of J-V curves of wide-bandgap perovskite solar cells prepared based on the thin films of Example 2 and Comparative Examples 2-3 in the application example;

[0036] Figure 5This is a stability test curve under continuous illumination of the wide bandgap perovskite solar cell prepared based on the thin films of Example 2 and Comparative Example 3 in the application example. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The following embodiments are provided to better further understand the present invention, but are not limited thereto and do not limit the content and scope of protection of the present invention. Any product that is identical or similar to the present invention and is obtained by anyone under the guidance of the present invention or by combining the features of the present invention with those of other prior arts falls within the scope of protection of the present invention.

[0038] Example 1

[0039] Prepare the perovskite precursor solution to make the perfluoroalkyl-substituted diamine cation (NH3 + The doping concentration of )2(CF2)2 is 0.75 mol% (compared to the B-site cation).

[0040] Specifically, a perovskite precursor solution containing lead iodide (PbI2), lead bromide (PbBr2), cesium iodide (CsI), methylamine iodide (FAI), methylamine bromide (MABr), methylamine chloride (MACl), perfluoroalkyl-substituted ethylenediamine dihydrochloride (F-DACl2), and rubidium iodide (RbI) is prepared with DMF and DMSO as a mixed solvent. The feed ratio of each substance is 680 mg: 12.2 mg: 20.8 mg: 240.5 mg: 3.4 mg: 11.5 mg: 2.3 mg: 10.2 mg: 800 μL: 200 μL (methylamine chloride will evaporate during the film preparation process). The solution is heated and stirred at 60°C for 1-3 h, 3 h in this embodiment, and filtered through a polytetrafluoroethylene filter membrane with a pore size of 0.45 μm for standby use.

[0041] Perovskite films were prepared using a one-step anti-solvent method in a nitrogen glove box at 20-25°C (22°C in this example). An appropriate amount of perovskite precursor solution was dripped onto a substrate to cover the entire surface. The spin coating process was a two-step process, with the first step being at 1000 rpm for 10 seconds, followed by acceleration to the second step at 5000 rpm for 40 seconds. Between the 22nd and 18th seconds before the end of the process, 200 μL of ethyl acetate was continuously applied to the rotating substrate to promote perovskite crystallization. The resulting perovskite film was then annealed at a temperature of 100-120°C (110°C in this example) for 15-40 minutes (30 minutes in this example) to obtain a metal halide-doped perovskite film.

[0042] Example 2

[0043] Preparation of perovskite precursor solution: In this embodiment, (NH3 + )2CF2 cation doping concentration is 0.75mol% (compared to B-site cation). Specifically, a perovskite precursor solution containing lead iodide (PbI2), lead bromide (PbBr2), cesium iodide (CsI), methylammonium iodide (FAI), methylamine bromide (MABr), and perfluoroalkyl-substituted dimethyldiamine dihydrochloride (F-DACl2) in DMF and DMSO as a mixed solvent is prepared. The material ratio of each substance is 507mg:154.2mg:18.2mg:192.5mg:36.5mg:1.8mg:800μL:200μL. The solution is heated and stirred at 60°C for 2-5h, 3h in this embodiment. Filter through a 0.45μm pore size polytetrafluoroethylene filter membrane and set aside.

[0044] The remaining steps and process parameters are the same as those in Example 1.

[0045] Comparative Example 1

[0046] The only difference between this comparative example and Example 1 is that no perfluoroalkyl-substituted ethylenediamine dihydrochloride is added, and the remaining steps and process parameters are the same as those in Example 1.

[0047] Comparative Example 2

[0048] The only difference between this comparative example and Example 2 is that no perfluoroalkyl-substituted methylenediamine dihydrochloride is added, and the remaining steps and process parameters are the same as those of Example 1.

[0049] Comparative Example 3

[0050] The only difference between this comparative example and Example 2 is that methylenediamine dihydrochloride is used instead of perfluoroalkyl-substituted methylenediamine dihydrochloride to obtain A-doped MDA 2+ of metal halide perovskite thin films.

[0051] Application example: Preparation of perovskite solar cells

[0052] Product perovskite solar cell cell structure such as Figure 1 As shown, it includes an indium tin oxide (ITO) glass substrate as a battery substrate, a hole transport layer, an F-DA 2+ The specific preparation steps of the five parts of the cation-doped perovskite layer, electron transport layer and metal electrode are as follows:

[0053] S1: Setting up the battery substrate;

[0054] S1-1: Clean the ITO glass substrate by ultrasonically cleaning it with detergent, deionized water, ethanol, acetone, and ethanol for 15 minutes each. After cleaning, dry the substrate with nitrogen gas flow and then treat it with ultraviolet ozone for 15 to 30 minutes. In this embodiment, the treatment is 20 minutes.

[0055] S2: Preparation of hole transport layer:

[0056] S2-1: Preparation of NiO x Aqueous solution of nanocrystals: nickel oxide (NiO x The nanocrystal powder was added to ultrapure water (in this example, the concentration was 10 mg / mL). The mixture was shaken and sonicated for 5 minutes each. The mixture was filtered through a 0.45 μm pore size polytetrafluoroethylene membrane and then used.

[0057] S2-2: Preparing an organic solution of a conjugated organic small molecule containing a phosphate group: Specifically, using [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz) to prepare a Me-4PACz anhydrous ethanol solution with a concentration of 0.5-1.0 mg / mL, 1.0 mg / mL in this embodiment, shaking and sonicating for 5-15 minutes each, 10 minutes in this embodiment, and filtering through a 0.45 μm pore size polytetrafluoroethylene filter membrane for later use;

[0058] S2-3: Take the prepared NiO x An aqueous solution of nanocrystals was spin-coated on an ITO glass substrate at 3000 rpm and then annealed at 150 °C for 15 min in clean air and then immediately transferred to a glove box;

[0059] S2-4: In a nitrogen glove box, anhydrous ethanol solution of Me-4PACz was spin-coated on the prepared NiO at a speed of 3000 rpm. x The film was deposited on a substrate with a layer and then annealed at 110°C in a glove box for 10 min.

[0060] S3: Preparation of F-DA 2+ Cation-doped perovskite layer:

[0061] S3-1: Prepare a surface passivation solution: Use p-trifluoromethylphenylethylamine iodate (CF3-PEAI) as the surface passivation agent for the perovskite film. The concentration of the passivation solution is 1.5 mg / mL. The solvent used is anhydrous isopropanol. Dissolve by shaking. Filter through a 0.45 μm pore size polytetrafluoroethylene filter membrane and set aside.

[0062] S3-2: During the film preparation process of Examples 1-2 and Comparative Examples 1-3, they are modified and passivated: during the high-speed rotation of the corresponding perovskite film (the rotation speed condition is 5000 rpm, 50s), 10 to 20 μL of an isopropanol solution of ethylenediamine iodate is added to the center of the perovskite film, 15 μL in this embodiment; and the passivated perovskite film active layer is obtained.

[0063] S4: Preparation of electron transport layer:

[0064] S4-1: Using vacuum thermal evaporation to deposit lithium fluoride (LiF) on the surface of the perovskite film to form a passivation layer with a thickness of 0.5 to 1 nm, which is 1 nm in this embodiment;

[0065] S4-2: Continue to deposit carbon 60 (C60) with a thickness of 20 to 40 nm as an electron transport layer using a vacuum thermal evaporation method, and in this embodiment, 20 nm;

[0066] S4-3: Continue to deposit 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP, bathocuproine) with a thickness of 6 nm by vacuum thermal evaporation.

[0067] S5: Preparation of metal electrodes:

[0068] S5-1: Vacuum evaporation of silver electrodes on the electron transport layer with a vacuum degree of less than 5×10 -4 The evaporation rate is 1.5 angstroms per second, and the electrode thickness is 90 nm to 120 nm, and is 100 nm in this embodiment.

[0069] S5-2: Preparation of anti-reflection layer: A LiF layer with a thickness of 105-110 nm is deposited on the surface of the electrode by vacuum thermal evaporation method as an anti-reflection layer, and in this embodiment, the thickness is 110 nm, to increase the photocurrent.

[0070] Performance Testing

[0071] The solar cells prepared in the corresponding use cases were subjected to current-voltage (JV) tests under the illumination of a solar simulator. The average value of 10 parallel groups was taken for each group to obtain the JV curve and the photoelectric conversion efficiency of the cell. In the application example, the JV curves of the solar cells prepared based on the thin films of Example 1 and Comparative Example 1 were compared. Figure 2 The photovoltaic parameters obtained by the test are summarized in Table 1. It can be seen that the photoelectric conversion efficiency of the device prepared based on the film of Example 1 is 25.4%, while the corresponding control conversion efficiency is 22.5%. The battery prepared based on the film of Example 1 is significantly better than the control device.

[0072] Table 1 Performance test results of solar cells prepared based on the thin films of Example 1 and Comparative Example 1

[0073]

[0074] In the application example, the EQE curve of the wide bandgap perovskite solar cell prepared based on the film of Example 2 is as follows: Figure 3 As shown in the figure, the JV curve comparison of the wide bandgap perovskite solar cells prepared based on the films of Example 2 and Comparative Examples 2-3 is shown in Figure 4 The performance parameters are summarized in Table 2:

[0075] Table 2 Performance test results of solar cells made based on the thin films of Example 2 and Comparative Examples 2-3

[0076]

[0077] Figure 5 The stability test curve of the wide bandgap perovskite solar cell prepared based on the film of Example 2 and Comparative Example 3 under continuous illumination is shown in the table above. Figure 4-Figure 5 It can be seen that the perfluoroalkyl-substituted diamine cation (F-DA 2+ ) doped perovskite solar cells have higher photoelectric conversion efficiency, which is significantly better than that of the undoped perfluoroalkyl-substituted diamine cation (F-DA 2+ ) prepared devices, and compared with the conventional diamine cation (MDA) doped in Comparative Example 3 2+ ) showed a slight improvement in device efficiency, but a significant improvement in device stability under continuous illumination, effectively suppressing the aging phenomenon in wide-bandgap perovskites.

[0078] In summary, the present invention provides a method for effectively improving the stability of metal halide perovskites, including improving thermal stability, inhibiting ion migration and solving the problem of halogen segregation in wide-bandgap perovskites, that is, doping a certain amount of perfluoroalkyl-substituted diamine cations (F-DA) at the A position of the perovskite lattice. 2+ ).

[0079] F-DA 2+ It is highly hydrophobic and chemically inert, which helps to improve the resistance of perovskite to water and oxygen. Its double positive charge can enhance the electrostatic interaction with halide ions and significantly inhibit the migration and phase separation tendency of iodine / bromide ions. 2+ With a rigid skeleton and moderate size, it can form a multi-point hydrogen bond network in the crystal, further stabilizing the lattice and reducing the defect state density. 2+ Cation, F-DA 2+Without disrupting the three-dimensional structure of the perovskite, the film's density and crystal quality can be improved. Its excellent solution processing compatibility and energy level adaptability make it suitable for large-area device construction, contributing to the realization of photovoltaic devices with both high efficiency and stability. This invention provides a more optimized stability control strategy for wide-bandgap perovskites from the perspectives of molecular structure, crystal engineering, and device compatibility.

[0080] The embodiments described above provide a detailed description of the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements or similar substitutions made within the scope of the principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for improving the stability of metal halide perovskite, characterized in that: Including, doping perfluoroalkyl substituted diamine cation at the A position of metal halide perovskite ABX3, the chemical formula of perfluoroalkyl substituted diamine cation is (NH3 + )2(CF2) n , wherein n is selected from an integer of 1-4, and the molar ratio of the doped perfluoroalkyl-substituted diamine cation to the B-site cation is 0.001-0.01:

1.

2. The method for improving the stability of metal halide perovskite according to claim 1, wherein: In the metal halide perovskite ABX3, the A-site cation is CH3NH3 + 、CH(NH2)2 + , cesium ion, and rubidium ion, the B-position cation is at least one of lead ion and tin ion, and the X-position anion is at least one of iodide ion, bromide ion, and chloride ion.

3. The method for improving the stability of metal halide perovskite according to claim 1, wherein: The method for doping a perfluoroalkyl-substituted diamine cation at the A position of a metal halide perovskite ABX3 includes: preparing a perovskite precursor solution using a perfluoroalkyl-substituted diamine cation salt, a perovskite precursor material AX, a perovskite precursor material BX2 and a solvent as raw materials, forming a film using the perovskite precursor solution, and achieving doping of the perfluoroalkyl-substituted diamine cation at the A position after annealing.

4. The method for improving the stability of metal halide perovskite according to claim 3, characterized in that: A perovskite precursor solution is prepared by using a perfluoroalkyl-substituted diamine cation salt, a perovskite precursor material AX, and a perovskite precursor material BX2 in a molar ratio of 0.001-0.01:0.95-1:

1.

5. The method for improving the stability of metal halide perovskite according to claim 3, wherein: Film formation methods include spin coating, doctor blade coating, slit coating, vapor deposition combined with solution deposition, inkjet printing, or screen printing.

6. The method for improving the stability of metal halide perovskite according to claim 3, wherein: The annealing temperature is 90-200° C., and the annealing time is 5-60 minutes.

7. A doped metal halide perovskite material, characterized in that: The perovskite is prepared by the method for improving the stability of metal halide perovskite according to any one of claims 1 to 6.

8. Use of the doped metal halide perovskite material according to claim 7 in a photovoltaic device.

9. The use of the doped metal halide perovskite material in a photoelectric device according to claim 8, characterized in that: The photoelectric device is a solar cell based on the doped metal halide perovskite material, and the doped metal halide perovskite material is in the form of a thin film.

10. Use of the doped metal halide perovskite material in a photoelectric device according to claim 9, characterized in that: The solar cell includes a cell substrate, a hole transport layer, a doped metal halide perovskite material thin film active layer, an electron transport layer, and a top electrode or back electrode stacked in sequence.

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