A high-entropy perovskite material, a perovskite device and a method of improving stability of three-dimensional perovskite

Abstract

The application discloses a high-entropy perovskite material, a perovskite device and a method for improving stability of a three-dimensional perovskite, and belongs to the technical field of perovskite photoelectric materials. i1 )2(A j ) n‑1 B n X 3n+1 or (A i2 )(A j ) n‑ 1B n X 3n+1 ; in the formula, n is a positive integer, when n=1, A i1 is composed of at least four organic cations M i1 , A i2 is composed of at least four organic cations M i2 ; when n>1, A i1 is composed of at least three organic cations M i1 , A i2 is composed of at least three organic cations M i2 ; due to the increase of system entropy, the high-entropy perovskite material has more superior stability compared with a two-dimensional perovskite with a single A-site cation, and the high-entropy perovskite material can be applied to a perovskite device, so that the problem of long-term stability of the device can be solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of perovskite photoelectric materials, and particularly relates to a high-entropy perovskite material, a perovskite device and a method for improving the stability of a three-dimensional perovskite. BACKGROUND

[0002] The organic-inorganic halide perovskite material is a material with a composition of ABX3, X is an anion, generally Cl - , I - or Br - . A and B are cations, the A-site cation mainly includes a methylammonium ion, a formamidinium ion or a cesium ion, and the B-site cation mainly includes a lead or tin ion. The B and X site ions form a BX6 octahedron, and A is located in the cavity of the four BX6 octahedrons. According to the difference in structural dimension, the halide perovskite can be divided into zero-dimensional, one-dimensional, two-dimensional and three-dimensional perovskites.

[0003] When the A-site cation becomes larger, the void in the inorganic framework is too small to accommodate the organic cation with a larger size, at this time, the inorganic octahedron will be forced to extend in some directions, forming a two-dimensional or quasi-two-dimensional perovskite with a layered structure, and the general structure formula can be represented as (P) m (A) n-1 B n X 3n+1 . When P is a monovalent cation, m=2, which is a Ruddlesden-Popper (RP) type perovskite; when P is a divalent cation, m=1, which is a Dion-Jacobson (DJ) type perovskite. n represents the number of layers of the BI6 octahedron between the organic cations. When n=1, the general formula of the perovskite becomes P m BX4, at this time, the corresponding perovskite is a pure two-dimensional perovskite. The A-site cation of the common R-P type perovskite is an organic cation, and a single component alkylammonium or amidine cation with different carbon numbers is usually selected, such as butylammonium, hexylammonium, heptylammonium, or aromatic ammonium or amidine cations, such as phenethylammonium or ethylpyreneammonium cations.

[0004] Although the perovskite material has developed rapidly, the highest efficiency of a perovskite solar cell single junction is 25.7%, and significant breakthroughs have been made in the fields of light-emitting diodes, detectors and the like, but the stability problem of the perovskite material is still the biggest difficulty in its commercialization. At present, although compared with the bulk perovskite material, the low-dimensional perovskite material such as quantum dots and two-dimensional perovskite has better stability due to the action of ligands, but the overall stability still has a certain gap from the commercialization requirement.

[0005] The Chinese patent document with publication number CN108630825A discloses a high-stability perovskite material, the precursor solution of which is prepared by AX, BX and MX2; wherein A + is an organic cation with a halogen substituent, B + is a metal cation or an alkylammonium salt, M 2+ is a divalent metal cation, and X is a halogen element; the invention introduces a carbon-containing halogen-substituted organic component into the perovskite material to form a stable perovskite material with adjustable dimensions.

[0006] The Chinese patent document with publication number CN108649125A discloses a method for improving the humidity stability of perovskite, which improves the humidity stability of perovskite by introducing fluorocarbon hydrophobic chain RNH2 molecules to modify the surface of perovskite material, wherein the fluorocarbon hydrophobic chain RNH2 molecules are one or more of C n F 2n+1 NH2, C n F 2n+1 CH2NH2, C n F 2n+1 CH2CH2NH2 and C n F 2n+1 CH2CH2CH2NH2.

[0007] In the field of metal materials, the high-entropy effect, lattice distortion effect, slow diffusion effect and cocktail effect caused by the special component composition of high-entropy materials make them outstanding in many performance aspects. Combining high-entropy effect with the preparation of perovskite materials is expected to prepare perovskite materials with excellent performance. SUMMARY

[0008] The present application provides a high-entropy perovskite material, the preparation method of which is simple, highly repeatable and easy to mass-produce. Thanks to the effect of entropy, the high-entropy perovskite material has more superior stability than the two-dimensional perovskite with a single A-site cation in the prior art, and can prepare perovskite optoelectronic devices with more excellent performance.

[0009] The specific technical solutions adopted are as follows:

[0010] A high-entropy perovskite material, the general formula of which is represented as (A i1 )2(A j ) n-1 B n X 3n+1 or (A i2 )(A j ) n-1 B n X 3n+1; when the general formula is represented as (A i1 )2(A j ) n-1 B n X 3n+1 , the high-entropy perovskite material is a Ruddlesden-Popper (RP) type perovskite, when the general formula is represented as (A i2 )(A j ) n-1 B n X 3n+1 , the high-entropy perovskite material is a Dion-Jacobson type perovskite;

[0011] wherein n is a positive integer, when n = 1, A i1 is composed of at least four organic cations M i1 , A i2 is composed of at least four organic cations M i2 ; when n > 1, A i1 is composed of at least three organic cations M i1 , A i2 is composed of at least three organic cations M i2 ;

[0012] A j is a methylamine cation, a formamidinium cation or a cesium ion;

[0013] B is a divalent metal cation;

[0014] X is at least one of a halide ion or a pseudohalide ion;

[0015] the organic cations M i1 are selected from monovalent C3-C18 alkylammonium cations, monovalent C3-C18 alkylamidinium cations, monovalent C6-C50 aromatic ammonium cations or monovalent C6-C50 aromatic amidinium cations;

[0016] the organic cations M i2 are selected from divalent C3-C18 alkyl-diammonium cations, divalent C3-C18 alkyl-diamidinium cations, divalent C6-C50 aromatic-diammonium cations or divalent C6-C50 aromatic-diamidinium cations.

[0017] the organic cations M i1 in A i1 and A j are both A-site cations; the organic cations M i2 in A i2 and A j are likewise both A-site cations.

[0018] The inventors found that four or more than four kinds of A-site cations can form a single two-dimensional perovskite crystal phase, and due to the increase of system entropy, the two-dimensional halide perovskite with four or more than four kinds of A-site cations has more superior stability than the two-dimensional perovskite with a single A-site cation, including thermal stability, wet stability, etc.; when the number of A-site cation types is less than four, a single-phase perovskite material cannot be prepared by using the corresponding precursor solution; only when the number of A-site cation types is four or more than four, a single-phase perovskite material can be prepared. Only due to the addition of multiple A-site cations, the increase of system entropy can promote the nucleation and growth of single-phase crystals.

[0019] Preferably, the organic cation M i1 is selected from butylammonium ion (BA + ), hexylammonium ion (HA + ), octylammonium ion (OA + ), heptylammonium ion (DA + ), dodecylammonium ion (DDA + ), phenethylammonium ion (PEA + ), anthracene ethylammonium ion (AEA + ) or ethylpyreneammonium (PREA + ) ion;

[0020] Preferably, the organic cation M i2 is selected from butyldiammonium ion (BDA 2+ ), hexyldiammonium ion (HDA 2+ ), octyldiammonium ion (ODA 2+ ), heptyldiammonium ion (DDA 2+ ) or dodecyldiammonium ion (DDDA 2+ );

[0021] B is Pb 2+ or Sn 2+ ;

[0022] X is at least one of I - , Br - , Cl - , CN - , SCN - or BF - .

[0023] The high-entropy perovskite material is prepared from a precursor solution;

[0024] When n = 1, the precursor solution is obtained by dissolving at least four (M i1 )X and BX2in a first organic solvent, or by dissolving at least four (M i2 )X2and BX2in a first organic solvent;

[0025] When n>1, the precursor solution is obtained by dissolving at least three (M i1 )X and A j X and BX2in a first organic solvent, or by dissolving at least three (M i2 )X2and A j X and BX2in a first organic solvent.

[0026] Preferably, the first organic solvent is at least one of dimethylformamide, dimethyl sulfoxide, gamma-butyrolactone, 2-methoxyethanol, acetonitrile, tetramethyl sulfoxide, propylene carbonate, dimethylacetamide, dimethylacetoacetamide and N-methyl-2-pyrrolidone.

[0027] Further preferably, when n=1, the ratio of the total moles of each (M i1 )X to the moles of BX2is 2:1, the ratio of the total moles of each (M i2 )X2to the moles of BX2is 1:1, and the mole fraction of each (M i1 )X is the same.

[0028] When n>1, the ratio of the total moles of each (M i1 )X to the moles of A j X and BX2is 2:n-1:n, the ratio of the total moles of each (M i2 )X2to the moles of A j X and BX2is 1:n-1:n, and preferably, the mole fraction of each (M i2 )X2is the same.

[0029] Preferably, the high-entropy perovskite material is a high-entropy perovskite thin film, which is prepared by spin-coating the precursor solution onto a substrate while adding an anti-solvent dropwise during the spin-coating process, and heating after the spin-coating process to obtain the high-entropy perovskite thin film.

[0030] Specifically, in the preparation of the high-entropy perovskite thin film, the substrate can be a flexible or rigid substrate selected from ITO, FTO, AZO, n-Si, p-Si, etc., and the anti-solvent is at least one of diethyl ether (DE), chlorobenzene (CB), ethyl acetate (EA), dichloromethane (DCM) and toluene (MB).

[0031] Preferably, the high-entropy perovskite material is a high-entropy perovskite single crystal, which is prepared by the inverse temperature method, the anti-solvent method or the seed crystal method using the precursor solution.

[0032] Specifically, the steps of the anti-solvent method for preparing the high-entropy perovskite single crystal are as follows: placing a first container containing the precursor solution into a second container containing an anti-solvent, allowing the anti-solvent vapor in the second container to diffuse to the first container, and obtaining a high-entropy perovskite sheet-shaped single crystal after the anti-solvent completely diffuses into the first container; the anti-solvent is at least one of diethyl ether (DE), chlorobenzene (CB), ethyl acetate (EA), dichloromethane (DCM) and toluene (MB).

[0033] The application further provides a method for improving the stability of a three-dimensional perovskite, comprising the following steps:

[0034] (1) dissolving at least four (M i1 )X in a second organic solvent to obtain a passivation agent solution; or dissolving at least four (M i2 )X2 in a second organic solvent to obtain a passivation agent solution;

[0035] (2) coating the passivation agent solution on the surface of the three-dimensional perovskite, and preparing a passivated three-dimensional perovskite after heating;

[0036] The second organic solvent is isopropyl alcohol, chlorobenzene or a mixed solvent of isopropyl alcohol and chlorobenzene.

[0037] Preferably, the coating method is spin coating, and the heating condition is 80-120 DEG C for 1-10 minutes. The purpose of heating is to evaporate the residual organic solvent on the surface of the three-dimensional perovskite, so as to avoid the damage of the residual organic solvent to the three-dimensional perovskite, and ensure that the solute molecules in the passivation agent fully act on the surface of the three-dimensional perovskite.

[0038] After the three-dimensional perovskite is passivated by the above method, the surface quality of the perovskite is significantly improved, the non-radiative recombination is significantly reduced, and the carrier lifetime is significantly increased. Meanwhile, a high-entropy perovskite layer is formed on the surface of the three-dimensional perovskite, which can effectively prevent the damage of water in the air to the three-dimensional perovskite, and further significantly improve the stability of the optoelectronic device.

[0039] The application further provides a perovskite device using the high-entropy perovskite material or the passivated three-dimensional perovskite.

[0040] The high-entropy perovskite material or the passivated three-dimensional perovskite can be applied to different perovskite optoelectronic devices, so as to solve the problem of long-term stability of the device.

[0041] Compared with the prior art, the application has the following beneficial effects:

[0042] (1) The high-entropy perovskite material prepared by the method has more excellent stability, including thermal stability and wet stability, compared with single A-site cation monophase two-dimensional / quasi-two-dimensional perovskite, and the high-entropy perovskite material applied to a perovskite photoelectric device can solve the problem of long-term stability of the device.

[0043] (2) The preparation method of the high-entropy perovskite material is simple, has high repeatability, and is suitable for large-scale commercial production.

[0044] (3) Compared with the single-component passivation agent in the prior art, the passivation agent solution provided by the application mixes at least four halides or pseudohalides corresponding to the organic cations, forms a high-entropy perovskite layer on the original three-dimensional perovskite, effectively passivates various defects on the surface of the three-dimensional perovskite, which makes the perovskite battery device have extremely high open-circuit voltage and photoelectric conversion efficiency, and at the same time greatly improves the stability of the device; for example, the three-dimensional perovskite passivated by the application is applied to perovskite solar cells of a formal structure and a reverse structure, which can effectively improve the conversion efficiency of the perovskite solar cells.

[0045] (4) The method for improving the stability of the three-dimensional perovskite provided by the application is easy to implement, has strong universality, wide application range, and good universality, and the high-entropy perovskite material or the three-dimensional perovskite after passivation provided by the application can be applied to different photoelectric devices, and can play its excellent photoelectric conversion performance. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 X-ray diffraction patterns of the perovskite thin films of Example 1 and Comparative Example 3 after high-temperature heating.

[0047] Figure 2 J-V curve comparison diagrams of the perovskite solar cells of Example 2 and Comparative Example 1 of a formal structure and a reverse structure, wherein (a) is a J-V curve comparison diagram of the perovskite solar cells of a formal structure, and (b) is a J-V curve comparison diagram of the perovskite solar cells of a reverse structure.

[0048] Figure 3 A statistical diagram of photoelectric conversion efficiency of the perovskite solar cells of Example 2, Comparative Example 1 and Comparative Example 2 of a formal structure.

[0049] Figure 4 A stability test diagram of the perovskite solar cells of Example 2 and Comparative Example 2 under the condition of 85 DEG C and relative humidity of 65%.

[0050] Figure 5 X-ray diffraction pattern of the DJ-type high-entropy perovskite thin film of Example 3.

[0051] Figure 6 X-ray diffraction pattern of the RP-type high-entropy perovskite thin film with aromatic cations for Example 4.

[0052] Figure 7 Picture of the RP-type high-entropy perovskite single crystal for Example 5 under microscope.

[0053] Figure 8 X-ray diffraction pattern of the RP-type high-entropy perovskite thin film for Example 6. DETAILED DESCRIPTION

[0054] The application will be further clarified by the following examples, which should not be construed as limiting the scope of the application.

[0055] Example 1

[0056] RP-type high-entropy perovskite thin film (BA 0.2 HA 0.2 OA 0.2 DA 0.2 DDA 0.2 )2PbI4was prepared with BAI, HAI, OAI, DAI, DDAI and PbI2as raw materials.

[0057] 1) At room temperature, BAI, HAI, OAI, DAI, DDAI and PbI2were dissolved in DMF to prepare a mixed solution, the concentration of (BA 0.2 HA 0.2 OA 0.2 DA 0.2 DDA 0.2 )2PbI4was 0.5 M, and the solution was stirred on a magnetic stirrer until completely dissolved;

[0058] 2) The clear solution obtained in step 1) was spin-coated on an ITO substrate, while 1 mL of anti-solvent DE was added during the spin-coating process. After spin-coating, the sample was heated at 100°C for 10 minutes to obtain a single-phase high-entropy perovskite thin film.

[0059] Example 2

[0060] A passivation solution was prepared with BAI, HAI, OAI, DAI, DDAI as raw materials to passivate the three-dimensional perovskite thin film.

[0061] 1) At room temperature, BAI, HAI, OAI, DAI, DDAI were dissolved in IPA to prepare a mixed solution with a total concentration of 5 mM, and the solution was stirred on a magnetic stirrer until completely dissolved to obtain a passivation solution;

[0062] 2) The passivation agent solution of step 1) is spin-coated on the surface of the three-dimensional perovskite film, after spin-coating, 100℃ heating for 1 minute, to obtain the passivated three-dimensional perovskite film;

[0063] The three-dimensional perovskite film obtained in step 2) is prepared into a complete perovskite solar cell formal and reverse structure device.

[0064] The formal structure perovskite solar cell is from bottom to top in turn: conductive substrate, electron transport layer, passivated three-dimensional perovskite film light absorbing layer, hole transport layer and top electrode; the reverse structure perovskite solar cell is from bottom to top in turn: conductive substrate, hole transport layer, passivated three-dimensional perovskite film light absorbing layer, electron transport layer and top electrode.

[0065] Example 3

[0066] BDAI2, HDAI2, ODAI2, DDAI2, DDDAI2 and PbI2 as raw materials to prepare n = 1 DJ type high-entropy perovskite film (BDA 0.2 HDA 0.2 ODA 0.2 DDA 0.2 DDDA 0.2 )PbI4.

[0067] 1) At room temperature, BDAI2, HDAI2, ODAI2, DDAI2, DDDAI2 and PbI2 are dissolved in DMF to prepare a mixed solution, (BDA 0.2 HDA 0.2 ODA 0.2 DDA 0.2 DDDA 0.2 )PbI4 concentration is 0.5M, and stirring on a magnetic stirrer until completely dissolved;

[0068] 2) The clear solution obtained in step 1) is spin-coated on the ITO substrate, while adding 1mL of anti-solvent DE during spin-coating, after spin-coating, 100℃ heating for 10 minutes, to obtain a single-phase high-entropy perovskite film.

[0069] Example 4

[0070] BAI, PEAI, OAI, DDAI, AEAI and PbI2 as raw materials to prepare n = 1 RP type high-entropy perovskite film (BA 0.2 PEA 0.2 OA 0.2 AEA 0.2 DDA 0.2 )2PbI4.

[0071] 1) At room temperature, BAI, PEAI, OAI, AEAI, DDAI and PbI2 were dissolved in DMF to prepare a mixed solution, (BA 02 PEA 02 OA 02 AEA 02 DDA 02 )2PbI4concentration was 0.5M, and stirred on a magnetic stirrer until completely dissolved;

[0072] 2) The clear solution obtained in step 1) was spin-coated on an ITO substrate, while adding 1 mL of anti-solvent DE during the spin-coating process. After spin-coating, heating at 100°C for 10 minutes, a single-phase high-entropy perovskite thin film was obtained.

[0073] Example 5

[0074] RP-type high-entropy perovskite single crystal (BA 0.2 HA 0.2 OA 0.2 DA 0.2 DDA 0.2 )2PbI4was prepared using BAI, HAI, OAI, DAI, DDAI and PbI2 as raw materials, n = 1.

[0075] 1) At room temperature, BAI, HAI, OAI, DAI, DDAI and PbI2 were dissolved in γ-butyrolactone to prepare a mixed solution, (BA 0.2 HA 0.2 OA 0.2 DA 0.2 DDA 0.2 )2PbI4concentration was 1M, and stirred on a magnetic stirrer until completely dissolved;

[0076] 2) The clear solution obtained in step 1) was placed in a second container containing anti-solvent diethyl ether, and the anti-solvent vapor in the second container was allowed to diffuse into the first container. After the anti-solvent completely diffused into the first container, a high-entropy perovskite sheet-shaped single crystal was obtained.

[0077] Example 6

[0078] RP-type high-entropy perovskite thin film (BA 0.2 PEA 0.2 OA 0.2 DA 0.2 DDA 0.2 )2MA3Pb4I 13 was prepared using BAI, PEAI, OAI, DAI, DDAI, MAI and PbI2 as raw materials, n = 4.

[0079] 1) BAI, HAI, OAI, DAI, DDAI, MAI and PbI2 were dissolved in DMF at room temperature to prepare a mixed solution, (BA 0.2 PEA 0.2 OA 0.2 DA 0.2 DDA 0.2 )2MA3Pb4I 13 with a concentration of 0.5 M and stirred on a magnetic stirrer until completely dissolved;

[0080] 2) The clear solution obtained in step 1) was spin-coated on an ITO substrate, and after spin-coating, the sample was heated at 100°C for 10 minutes to obtain a single-phase high-entropy perovskite film.

[0081] Comparative Example 1

[0082] In Comparative Example 1, the surface of the three-dimensional perovskite film was not passivated, and the perovskite solar cell prepared therefrom had a structure identical to that of Example 2.

[0083] Comparative Example 2

[0084] In Comparative Example 2, the method was identical to that of Example 2, except that the surface of the three-dimensional perovskite film was passivated using a solution of a single component (DDAI), and the perovskite solar cell prepared therefrom had a structure identical to that of Example 2.

[0085] Comparative Example 3

[0086] In Comparative Example 3, the method was identical to that of Example 1, except that a precursor solution was prepared using DDAI and PbI2, and a two-dimensional perovskite film was then prepared.

[0087] Sample Analysis

[0088] (1) X-ray diffraction test:

[0089] The perovskite films prepared in Example 1 and Comparative Example 3 were heated to 130°C in air with a relative humidity of about 65% and left to stand for 1 hour to test their thermal stability, and the results are shown in FIG. 1. Figure 1 As shown in FIG. 1, after high-temperature heating, obvious diffraction peaks of lead iodide appeared in the X-ray diffraction pattern of Comparative Example 3, but almost none appeared in Example 1, proving that the high-entropy perovskite film prepared by the method of the present application has better thermal stability.

[0090] The X-ray diffraction pattern of the DJ-type high-entropy perovskite film prepared in Example 3 is shown in FIG. 2. Figure 5 As shown in FIG. 2, although multiple components were incorporated, the X-ray diffraction pattern exhibited a single diffraction peak, proving that (BDA 0.2 HDA 0.2 ODA0.2 DDA 0.2 DDDA 0.2 Successful synthesis of PbI4;

[0091] The X-ray diffraction pattern of the RP-type high-entropy perovskite thin film prepared in Example 4 is shown below. Figure 6 As shown, although multiple components were incorporated, the X-ray diffraction pattern exhibits a single diffraction peak, proving that (BA) 0.2 PEA 0.2 OA 0.2 AEAA 0.2 DDA 0.2 Successful synthesis of 2PbI4;

[0092] The X-ray diffraction pattern of the RP-type high-entropy perovskite thin film prepared in Example 6 is shown below. Figure 8 As shown, although multiple components were incorporated, the X-ray diffraction pattern exhibited a single diffraction peak at low angles, proving that (BA) 0.2 PEA 0.2 OA 0.2 DA 0.2 DDA 0.2 )2MA3Pb4I 13 Successful synthesis.

[0093] (2) Morphological test:

[0094] The image of the RP-type high-entropy perovskite single crystal obtained in Example 5 is shown under a microscope. Figure 7 As shown, it appears as yellow flakes, consistent with the theoretical morphology of two-dimensional perovskite single crystals, proving that the method of this invention has successfully synthesized (BA) 0.2 HA 0.2 OA 0.2 DA 0.2 DDA 0.2 )2PbI4 single crystal.

[0095] (3) Photoelectric conversion efficiency test:

[0096] Comparing the performance of the perovskite solar cells with the formal and inverse structures prepared in Example 2 and Comparative Example 1, the JV curves are as follows: Figure 2 As shown in (a) and (b), the perovskite solar cell with the formal structure prepared in Example 2 has a photoelectric conversion efficiency of 24.9%, which is a significant improvement compared to the 21.2% of the perovskite solar cell with the formal structure in Comparative Example 1. The perovskite solar cell with the inverted structure prepared in Example 2 has a photoelectric conversion efficiency of 22.1%, which is also a certain improvement compared to the 21.3% of the perovskite solar cell with the inverted structure in Comparative Example 1. This demonstrates that the method of the present invention is a general passivation technique for the surface of perovskite optoelectronic devices.

[0097] The formal structure of perovskite solar cell photoelectric conversion efficiency statistics chart prepared by example 2, comparative example 1 and comparative example 2 Figure 3 It can be obtained that the promotion effect of high-entropy passivation on the efficiency of perovskite solar cell device is higher than that of single-component passivation agent.

[0098] (4) Stability test:

[0099] As shown in Figure 4 , the formal structure perovskite solar cell prepared by example 2. After aging at 85℃, relative humidity 65% for 70 hours, it can still maintain 90% of the initial efficiency, and there is no downward trend; while the perovskite solar cell of comparative example 2 only retains 78% of the original efficiency, and shows a continuous downward trend.

[0100] The above examples are used to explain the technical solutions of the present application in detail. It should be understood that the above examples are only specific embodiments of the present application and are not used to limit the present application. Any modification, supplement or similar substitution within the principle range of the present application should be included in the protection scope of the present application.

Claims

1. A high-entropy perovskite material, characterized in that, The general formula for the high-entropy perovskite material is (A i1 )2(A j ) n-1 B n X 3n+1 or (A) i2 (A) j ) n-1 B n X 3n+1 ; In the formula, n is a positive integer. When n=1, A i1 Composed of at least four organic cations M i1 Composition, A i2 Composed of at least four organic cations M i2 Composition; when n>1, A i1 Composed of at least three organic cations M i1 Composition, A i2 Composed of at least three organic cations M i2 composition; A j It is a methylamine cation; B is Pb 2+ ; X is I - ,Br - or Cl - ; Organic cation M i1 Selected from monovalent C3-C18 alkylammonium cations, phenylacetium ions, anthracene acetium ions, or ethylpyrene ions; Organic cation M i2 Selected from divalent C3-C18 alkyl diammonium cations.

2. The high-entropy perovskite material according to claim 1, characterized in that, Organic cation M i1 Selected from butylammonium ion, hexylammonium ion, octylammonium ion, heptylammonium ion, dodecammonium ion, phenylethylammonium ion, anthracene ethylammonium ion, or ethylpyrene ammonium ion; Organic cation M i2 It is selected from butyl diammonium ion, hexyl diammonium ion, octyl diammonium ion, heptyl diammonium ion or dodecyl diammonium ion.

3. The high-entropy perovskite material according to claim 1, characterized in that, When n=1, the precursor solution of the high-entropy perovskite material consists of at least four (M i1 The product is obtained by dissolving M and BX2 in a first organic solvent, or by dissolving at least four (M) compounds in a first organic solvent. i2 The mixture of BX2 and BX2 is dissolved in a first organic solvent to obtain the product. When n > 1, the precursor solution of the high-entropy perovskite material consists of at least three (M i1 X and A j X and BX2 are dissolved in a first organic solvent to obtain X, or are obtained from at least three (M) i2 X2 and A j X and BX2 are obtained by dissolving them in a first organic solvent.

4. The high-entropy perovskite material according to claim 3, characterized in that, The first organic solvent is at least one selected from dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, 2-methoxyethanol, acetonitrile, tetramethyl sulfoxide, propylene carbonate, dimethylacetamide, dimethylacrylurea, and N-methyl-2-pyrrolidone.

5. The high-entropy perovskite material according to claim 3, characterized in that, The high-entropy perovskite material is a high-entropy perovskite thin film, prepared using the following method: The precursor solution was spin-coated onto the substrate, and an antisolvent was added dropwise during the spin-coating process. After spin-coating was completed, the substrate was heated to obtain a high-entropy perovskite film.

6. The high-entropy perovskite material according to claim 3, characterized in that, The high-entropy perovskite material is a high-entropy perovskite single crystal, which is prepared by the precursor solution through the inverse temperature method, the antisolvent method, or the seed crystal method.

7. The high-entropy perovskite material according to claim 6, characterized in that, The steps for preparing high-entropy perovskite single crystals using the anti-solvent method are as follows: The first container containing the precursor solution is placed in a second container containing the antisolvent, allowing the antisolvent vapor in the second container to diffuse into the first container, thereby obtaining a high-entropy perovskite single crystal.

8. The high-entropy perovskite material according to claim 5 or 7, characterized in that, The antisolvent is at least one selected from diethyl ether, chlorobenzene, ethyl acetate, dichloromethane, and toluene.

9. A method for improving the stability of three-dimensional perovskites, characterized in that, Includes the following steps: (1) At least four kinds (M) i1 X is dissolved in a second organic solvent to obtain a passivating agent solution; or at least four (M) i2 X2 is dissolved in a second organic solvent to obtain a passivating agent solution; organic cation M i1 Selected from monovalent C3-C18 alkylammonium cations, phenylacetium ions, anthracene acetium ions, or ethylpyrene ions; organic cations M i2 Selected from divalent C3-C18 alkyl diammonium cations; X is I - ,Br - or Cl - ; (2) A passivating agent solution is coated on the surface of a three-dimensional perovskite, and then heated to obtain a passivated three-dimensional perovskite; The second organic solvent is isopropanol, chlorobenzene, or a mixture of isopropanol and chlorobenzene.

10. A perovskite device, characterized in that, The high-entropy perovskite material of claim 1 or the passivated three-dimensional perovskite of claim 9 are applied.

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