Hybrid perovskite nanofiber membranes with high fluorescence stability and preparation method thereof

Abstract

The application provides a mixed-dimensional perovskite nanofiber membrane with high fluorescence stability and a preparation method thereof, perovskite solution and polymer solution are respectively configured, and the two are uniformly mixed to obtain a spinning solution, the spinning solution is prepared into a nanofiber membrane by using an electrospinning method, and finally the nanofiber membrane is heat-treated, and the mixed-dimensional perovskite nanofiber membrane with high fluorescence stability is obtained after natural cooling. By introducing perovskite raw materials in different forms of organic amine, mixed crystallization of low-dimensional perovskite and three-dimensional perovskite is formed in the crystallization process, internal defects of the perovskite are reduced, the mixed-dimensional perovskite with low defect density, good crystallization quality and high structural stability is obtained, and then the light absorption capacity and the light emission intensity of the mixed-dimensional perovskite nanofiber membrane are improved. The mixed-dimensional perovskite nanofiber membrane has high fluorescence brightness, stability and uniformity, and is suitable for application in the fields of flexible display, flexible light emission, anti-counterfeiting and the like.

Description

Technical Field

[0001] This invention relates to the field of perovskite photoluminescent thin film technology, and in particular to a mixed-fiber perovskite membrane with high fluorescence stability and its preparation method. Background Technology

[0002] Photoluminescent materials are functional materials that produce novel fluorescence through electron transitions on their surface or within the material when excited by ultraviolet light or laser light. Due to their excellent stealth, camouflage, anti-counterfeiting, and fluorescent indication properties, photoluminescent materials are widely used in flexible displays, flexible light emission, process monitoring, and product anti-counterfeiting identification.

[0003] Currently, commonly used luminescent materials include quantum dot materials and nanocrystalline materials. Quantum dots have the advantages of broad excitation spectrum, narrow and symmetrical emission spectrum, and tunable color. An invention patent (application number CN 20231171382.9) discloses a perovskite quantum dot material, its preparation method, and its applications. The method involves first mixing an organic cesium salt, an organic lead salt, an organic ligand, and polymer micropowder to obtain a perovskite precursor, and then secondly mixing an organic halide salt with the perovskite precursor to undergo an ionization reaction, thereby obtaining the perovskite quantum dot material. However, this method involves complex steps and a large number of raw materials, making the synthesis of quantum dot materials difficult, resulting in poor reproducibility and product stability.

[0004] Compared to quantum dots, nanocrystals possess a complete crystal structure and a larger nanoscale size, along with strong fluorescence and photon emission. Furthermore, the absorption and emission spectra of nanocrystals are continuous, resulting in fewer application limitations and enabling their widespread use in optoelectronics, catalysis, sensors, and biotechnology. While there is considerable work on the synthesis of perovskite quantum dots, there has been no significant breakthrough in the field of perovskite nanocrystal thin films. Conventional spin-coating methods produce perovskite films with poor thermal, humidity, and light stability, requiring low-humidity environments for film formation. Moreover, the film-forming properties are poor, meaning the resulting film materials must rely on a substrate for application and cannot form independently, hindering industrialization.

[0005] In view of this, it is necessary to design an improved mixed-dimensional perovskite nanofiber membrane with high fluorescence stability and its preparation method to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a mixed-dimensional perovskite nanofiber membrane with high fluorescence stability and its preparation method. The nanofiber membrane is prepared by electrospinning a mixture of mixed-dimensional perovskite and a polymer. The growth and crystallization of the mixed-dimensional perovskite are achieved by introducing raw materials in the form of organic amines to stabilize the perovskite crystal structure and avoid decomposition, thereby obtaining a mixed-dimensional perovskite nanofiber membrane with high fluorescence brightness, stability and uniformity.

[0007] To achieve the above-mentioned objectives, this invention provides a mixed-dimensional perovskite nanofiber membrane with high fluorescence stability, wherein the mixed-dimensional perovskite in the mixed-dimensional perovskite nanofiber membrane has the molecular formula (Al). m (A2) n-1 B n X 3n+1 The mixed-dimensional perovskite is achieved by introducing raw materials in the form of organic amines.

[0008] As a further improvement of the present invention, A1 is one of phenylethylamine, butylamine, m-fluorophenylethylamine, and ethylenediamine; A2 is methylamine or formamidinium; B is one of Pb, Sn, and Bi; and X is one or more of I, Cl, and Br. The molar ratio of A1 to A2 is m:(n-1), where m=1 or 2, and n=10~50.

[0009] As a further improvement of the present invention, the diameter of the fibers in the mixed-dimensional perovskite nanofiber membrane is 50 nm to 4 μm; the photoluminescence quantum yield of the mixed-dimensional perovskite nanofiber membrane is not less than 45%.

[0010] The present invention also provides a method for preparing a mixed-dimensional perovskite nanofiber membrane with high fluorescence stability as described in any one of the above-mentioned methods, wherein the mixed-dimensional perovskite in the mixed-dimensional perovskite nanofiber membrane has the molecular formula (Al). m (A2) n-1 B n X 3n+1 This includes the following steps:

[0011] S1. Prepare a perovskite solution and a polymer solution separately, and mix them evenly to obtain a spinning solution; the solutes in the perovskite solution are A1X, A2X and BX2, wherein A1 is one of phenylethylamine, butylamine, m-fluorophenylethylamine, and ethylenediamine, A2 is methylamine or formamidinium, B is one of Pb, Sn, and Bi, and X is one or more of I, Cl, and Br; the molar ratio of A1X to A2X is m:(n-1); m=1, 2, n=10~50; the molar ratio of A1X and A2X mixed with BX2 is 1:(0.8~1.2);

[0012] S2. Inject the spinning solution from step S1 into a syringe and prepare a nanofiber membrane using electrospinning.

[0013] S3. The nanofiber membrane obtained in step S2 is subjected to heat treatment and then naturally cooled to obtain a mixed-dimensional perovskite nanofiber membrane with high fluorescence stability.

[0014] As a further improvement of the present invention, in step S1, the concentration of the perovskite solution is 0.005~4.0 mmol / mL, and the solid content of the polymer solution is 5wt%~35wt%.

[0015] As a further improvement of the present invention, in the spinning solution, the volume ratio of the perovskite solution to the polymer solution is 1:(1~50).

[0016] As a further improvement of the present invention, in step S3, the temperature of the heat treatment is 50~140℃ and the time is 10min~24h.

[0017] As a further improvement of the present invention, in step S1, the solute in the polymer solution is one of polyvinylidene fluoride, polyurethane, and polyacrylonitrile, and the solvent is one or more of N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, and N-methylpyrrolidone.

[0018] As a further improvement of the present invention, in step S1, the solvent in the perovskite solution is one or more of N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, and N-methylpyrrolidone.

[0019] As a further improvement of the present invention, in step S2, the spinning voltage of the electrospinning method is 5~25 kV, the injection speed is 0.1~0.5 mm / min, and the receiving speed is 30~150 rpm / min.

[0020] As a further improvement of the present invention, the spinning solution also includes additives, namely oleic acid and oleylamine.

[0021] The beneficial effects of this invention are:

[0022] 1. This invention relates to a highly fluorescently stable mixed-dimensional perovskite nanofiber membrane and its preparation method. The method involves mixing a mixed-dimensional perovskite solution with a polymer solution, preparing a nanofiber membrane using electrospinning, and then subjecting it to heat treatment for crystallization to obtain a highly fluorescently stable mixed-dimensional perovskite nanofiber membrane. This invention achieves the growth and crystallization of the mixed-dimensional perovskite by introducing organic amines as raw materials, thereby stabilizing the perovskite crystal structure and preventing its structural decomposition. This results in a mixed-dimensional perovskite nanofiber membrane with high fluorescence brightness, stability, and uniformity. This nanofiber membrane is suitable for applications in flexible displays, flexible light emission, and anti-counterfeiting fields.

[0023] 2. In the preparation method of this invention, the perovskite solution simultaneously contains monoamines or monoamidines that can yield three-dimensional perovskites and diamines or polyamines that can yield low-dimensional perovskites. Through the mixing of raw materials in the form of organic amines, the low-dimensional perovskite and three-dimensional perovskite formed during the crystallization process are mixed and crystallized, which can effectively reduce the internal defects of the perovskite, resulting in a mixed-dimensional perovskite with low defect density, good crystal quality, and high structural stability, thereby improving the light absorption capacity and luminescence intensity of the mixed-dimensional perovskite. Furthermore, using appropriate heat treatment conditions to treat the nanofiber membrane can improve the fiber crystal orientation caused by the spinning process, further improving the crystallization effect of the perovskite, thereby improving its crystallization stability and obtaining a high-quality fluorescent film. This preparation method is simple, has a short preparation process, is highly feasible, and is suitable for large-area preparation, possessing advantages for industrialization.

[0024] 3. This invention ensures the smooth realization of electrospinning by limiting the concentrations of the perovskite solution and polymer solution in the spinning solution, the types of solvents, and the types of perovskite raw materials and polymers; and the obtained nanofiber membrane has high photoluminescence quantum yield, high fluorescence stability, and uniformity, and can be repeatedly recycled and reused through a simple solvent dissolution and re-film formation method, achieving high economic benefits. Attached Figure Description

[0025] Figure 1 The image shows the photoluminescence intensity of the mixed-dimensional perovskite nanofiber membrane with high fluorescence stability prepared in Example 1 of this invention.

[0026] Figure 2 The image shows the XRD pattern of the high fluorescence stability mixed-dimensional perovskite nanofiber membrane prepared in Example 1 of this invention.

[0027] Figure 3 The image shows the SEM structure of the high fluorescence stability mixed-dimensional perovskite nanofiber membrane prepared in Example 1. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0030] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0031] A mixed-dimensional perovskite nanofiber membrane with high fluorescence stability, wherein the mixed-dimensional perovskite in the mixed-dimensional perovskite nanofiber membrane has the molecular formula (A1). m (A2) n-1 B n X 3n+1 The mixed-fiber perovskite is achieved by introducing organic amines as raw materials. A1 is one of phenylethylamine, butylamine, m-fluorophenylethylamine, or ethylenediamine; A2 is methylamine or formamidinium; B is one of Pb, Sn, or Bi; and X is one or more of I, Cl, or Br. The molar ratio of A1 to A2 is m:(n-1), where m = 1 or 2, and n = 10~50. The diameter of the fibers in the mixed-fiber perovskite nanofiber membrane is 50 nm to 4 μm; the photoluminescence quantum yield of the mixed-fiber perovskite nanofiber membrane is not less than 45%.

[0032] This invention achieves the growth and crystallization of mixed-dimensional perovskite by introducing organic amine raw materials, thereby stabilizing the perovskite crystal structure and preventing its structural decomposition, resulting in a mixed-dimensional perovskite nanofiber membrane with high fluorescence brightness, stability, and uniformity. This nanofiber membrane is suitable for applications in flexible displays, flexible light emission, anti-counterfeiting, and other fields.

[0033] A method for preparing a mixed-dimensional perovskite nanofiber membrane with high fluorescence stability, wherein the mixed-dimensional perovskite in the mixed-dimensional perovskite nanofiber membrane has the molecular formula (Al). m (A2) n-1 B n X 3n+1 This includes the following steps:

[0034] S1. Prepare a perovskite solution and a polymer solution separately, and mix them evenly to obtain a spinning solution; the solutes in the perovskite solution are A1X, A2X and BX2, wherein A1 is one of phenylethylamine, butylamine, m-fluorophenylethylamine, or ethylenediamine, A2 is methylamine or formamidinium, B is one of Pb, Sn, or Bi, and X is one or more of I, Cl, or Br. The molar ratio of A1X to A2X is m:(n-1); m=1, 2, n=10~50; the molar ratio of A1X and A2X mixed with BX2 is 1:(0.8~1.2).

[0035] S2. Inject the spinning solution from step S1 into a syringe and prepare a nanofiber membrane using electrospinning.

[0036] S3. The nanofiber membrane obtained in step S2 is subjected to heat treatment and then naturally cooled to obtain a mixed-dimensional perovskite nanofiber membrane with high fluorescence stability.

[0037] In particular, the perovskite solution used in this preparation method contains both monoamines or monoamidines that can produce three-dimensional perovskites and diamines or polyamines that can produce low-dimensional perovskites. By mixing raw materials in the form of organic amines, the low-dimensional perovskites and three-dimensional perovskites formed during the crystallization process are mixed and crystallized, which can effectively reduce the internal defects of the perovskite and obtain mixed-dimensional perovskites with low defect density, good crystal quality and high structural stability, thereby improving the light absorption capacity and luminescence intensity of the mixed-dimensional perovskites.

[0038] Specifically, in step S1, the concentration of the perovskite solution is 0.005~4.0 mmol / mL, and the solid content of the polymer solution is 5wt%~35wt%. In the spinning solution, the volume ratio of the perovskite solution to the polymer solution is 1:(1~50). The solute in the polymer solution is one of polyvinylidene fluoride, polyurethane, or polyacrylonitrile, and the solvent is one or more of N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, and N-methylpyrrolidone. The solvent in the perovskite solution is one or more of N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, and N-methylpyrrolidone. The polymer acts as a supporting framework, ensuring the formation of the electrospun nanofiber membrane; simultaneously, the O and S elements in the polymer possess lone pairs of electrons, which can chelate with Pb in the perovskite, enabling the polymer to anchor the perovskite, inhibit ion migration, stabilize the perovskite structure, and passivate defects in the perovskite, thereby enhancing the fluorescence intensity of the nanofiber membrane.

[0039] This invention ensures the smooth realization of electrospinning film formation by limiting the concentrations of perovskite solution and polymer solution, the types of solvents, and the types of perovskite raw materials and polymers in the spinning solution. The resulting nanofiber membrane has high photoluminescence quantum yield, high fluorescence stability, and uniformity. It can also be repeatedly recycled and reused through a simple solvent dissolution and re-film formation method, achieving high economic benefits.

[0040] In step S3, the heat treatment temperature is 50~140℃, and the time is 10 min~24 h. By using appropriate heat treatment conditions to treat the nanofiber membrane, the fiber crystal orientation caused by the spinning process can be improved, further enhancing the crystallization effect of perovskite, thereby improving its crystallization stability and obtaining a high-quality fluorescent film. Simultaneously, it avoids the situation where the heat treatment temperature is too low to achieve the desired crystallization effect, and avoids the collapse and partial dissolution of the film material and the degradation of perovskite caused by excessively high temperatures. The preparation method of this invention is simple, has a short preparation process, is highly feasible, and is suitable for large-area preparation, possessing advantages for industrialization.

[0041] In some specific embodiments, in step S2, the spinning voltage of the electrospinning method is 5~25kV, the injection speed is 0.1~0.5 mm / min, and the receiving speed is 30~150 rpm / min.

[0042] In some specific embodiments, the spinning solution also includes additives, namely oleic acid and oleylamine.

[0043] Example 1

[0044] This embodiment provides a method for preparing a mixed-dimensional perovskite nanofiber membrane with high fluorescence stability, including the following steps:

[0045] S1. Prepare a perovskite solution (concentration of 0.04 mmol / mL) and a polyvinylidene fluoride (PVDF) polymer solution (solid content of 17 wt%), and mix them evenly to obtain a spinning solution. The solutes in the perovskite solution are PEACl (phenylethylamine chloride), MACl (methylamine chloride), and PbCl2, with a molar ratio of 2:9:10. The solvent is N,N-dimethylformamide, and the volume ratio of the perovskite solution to the polymer solution is 1:5.

[0046] S2. Inject the spinning solution from step S1 into a syringe and prepare a nanofiber membrane using electrospinning; the spinning voltage is 15 kV, the injection speed is 0.3 mm / min, and the receiving speed is 50 rpm / min.

[0047] S3. The nanofiber membrane obtained in step S2 is subjected to heat treatment at 70℃ for 20 min, followed by natural cooling to obtain a mixed-dimensional perovskite nanofiber membrane with high fluorescence stability (PEA2MA9Pb). 10 Cl 31 / PVDF).

[0048] Please see Figure 1 The figure shows the photoluminescence intensity of the mixed-dimensional perovskite nanofiber membrane with high fluorescence stability prepared in Example 1. As can be seen from the figure, the PL peak position of the mixed-dimensional perovskite is 470 nm, which is a blue fluorescent fiber membrane material.

[0049] Please see Figure 2 The figure shows the XRD pattern of the high fluorescence stability mixed-dimensional perovskite nanofiber membrane prepared in Example 1. As can be seen from the figure, the mixed-dimensional perovskite in the nanofiber membrane has good crystallinity.

[0050] Please see Figure 3The image shows the SEM structure of the high fluorescence stability mixed-dimensional perovskite nanofiber membrane prepared in Example 1. As can be seen from the image, the nanofibers in the mixed-dimensional perovskite nanofiber membrane prepared in Example 1 have good uniformity, resulting in a uniform nanofiber membrane structure and good mechanical properties.

[0051] The photoluminescence quantum yield (PLQY) and luminescence intensity of the high fluorescence stability mixed-dimensional perovskite nanofiber membrane prepared in Example 1 were tested. The results were as follows: its photoluminescence quantum yield was not less than 50%; after being stored in air for one month, its photoluminescence intensity decreased to 8% of the initial photoluminescence intensity (PL0); after being stored at 85% relative humidity for one month, its photoluminescence intensity decreased by 7% PL0; and after being stored at 50°C for one month, its photoluminescence intensity decreased by 10% PL0.

[0052] Example 2

[0053] Example 2 provides a method for preparing a mixed-dimensional perovskite nanofiber membrane with high fluorescence stability. The difference from Example 1 lies in the type of perovskite solution used. The solutes in the perovskite solution are BEAI (butyl iodide), MAI (methyl iodide), and PbI2, with a molar ratio of 2:19:20. The resulting mixed-dimensional perovskite nanofiber membrane is BA2MA. 19 Pb 20 I 61 / PVDF, the rest is roughly the same as in Example 1, and will not be described again here.

[0054] BA2MA prepared in Example 2 19 Pb 20 I 61 PVDF nanofiber membrane material appears black under natural light and red under ultraviolet light.

[0055] Comparative Example 1

[0056] Comparative Example 1 provides a method for preparing a perovskite nanofiber membrane. The difference from Example 1 is that in step S1, the solutes of the perovskite solution are MACl and PbCl2, and the molar ratio of the two is 1:1, resulting in a three-dimensional perovskite nanofiber membrane (MAPbCl3 / PVDF). The rest is roughly the same as in Example 1, and will not be repeated here.

[0057] Comparative Example 2

[0058] Comparative Example 2 provides a method for preparing a perovskite nanofiber membrane. The difference from Example 1 is that in step S1, the solutes in the perovskite solution are PEACl, MACl, and PbCl2, with a molar ratio of 2:3:4, resulting in a low-dimensional perovskite nanofiber membrane (PEA2MA3Pb4Cl).17 ( / PVDF), the rest is roughly the same as in Example 1, and will not be repeated here.

[0059] Comparative Example 3

[0060] Comparative Example 3 provides a method for preparing a mixed-fiber perovskite nanofiber membrane. The difference from Example 1 is that in step S1, the spinning solution contains only a perovskite solution and no polymer solution. The rest is roughly the same as in Example 1 and will not be repeated here.

[0061] Comparative Example 4

[0062] Comparative Example 4 provides a method for preparing a mixed-fiber perovskite nanofiber membrane. The difference from Example 1 is that in step S3, the film material is not heat-treated, but is air-dried naturally. The rest is roughly the same as Example 1, and will not be repeated here.

[0063] Comparative Example 5

[0064] Comparative Example 5 provides a method for preparing a mixed-fiber perovskite nanofiber membrane. The difference from Example 1 is that the heat treatment temperature in step S3 is 40°C. The rest is roughly the same as in Example 1 and will not be repeated here.

[0065] Comparative Example 6

[0066] Comparative Example 6 provides a method for preparing a mixed-fiber perovskite nanofiber membrane. The difference from Example 1 is that the heat treatment temperature in step S3 is 160°C. The rest is roughly the same as in Example 1 and will not be repeated here.

[0067] Comparative Example 7

[0068] Comparative Example 7 provides a method for preparing a mixed-fiber perovskite nanofiber membrane. The difference from Example 1 is that the heat treatment time in step S3 is 36 h. The rest is roughly the same as in Example 1 and will not be repeated here.

[0069] The mixed-dimensional perovskite nanofiber membranes prepared in Example 2 and Comparative Examples 1-7 were subjected to photoluminescence quantum yield (PLQY) and luminescence intensity stability tests. The luminescence intensity stability test included the photoluminescence intensity change rate Δ1 = ((PL0-PL1) / PL0) × 100% after one month of storage in an atmospheric environment, the photoluminescence intensity change rate Δ2 = ((PL0-PL2) / PL0) × 100% after one month of storage at 95% relative humidity, and the photoluminescence intensity change rate Δ3 = ((PL0-PL3) / PL0) × 100% after one month of storage at 50°C. The results are shown in the table below.

[0070] Table 1. Luminescent properties of mixed-dimensional perovskite nanofiber membranes in Example 2 and Comparative Examples 1-7

[0071]

[0072] Table 1 shows that the non-mixed-dimensional perovskite nanofiber membranes prepared in Comparative Examples 1 and 2 have lower photoluminescence quantum yields and lower luminescence intensity stability than the mixed-dimensional perovskite nanofiber membranes prepared in Examples 1 and 2. Comparative Example 3, with only perovskite solution in the spinning solution, was difficult to adapt to the electrospinning process and could not successfully obtain a perovskite nanofiber membrane. Data from Comparative Examples 4-6 show that suitable heat treatment conditions (temperature and time) are important factors affecting the good crystallization and fluorescence performance of the nanofiber membranes, and also improve the storage, humidity, and thermal stability of the perovskite self-supporting membranes.

[0073] In summary, this invention provides a mixed-dimensional perovskite nanofiber membrane with high fluorescence stability and its preparation method. The method involves mixing a mixed-dimensional perovskite solution with a polymer solution, preparing the nanofiber membrane using electrospinning, and then subjecting it to heat treatment and crystallization to obtain the mixed-dimensional perovskite nanofiber membrane with high fluorescence stability. The perovskite solution of this invention simultaneously contains monoamines or monoamidines that yield three-dimensional perovskites and diamines or polyamines that yield low-dimensional perovskites. Through the mixing of raw materials in the form of organic amines, the low-dimensional perovskite and three-dimensional perovskite formed during the crystallization process are mixed and crystallized, effectively reducing internal defects in the perovskite and resulting in a mixed-dimensional perovskite with low defect density, good crystal quality, and high structural stability. This improves the light absorption and luminescence intensity of the perovskite, resulting in a mixed-dimensional perovskite nanofiber membrane with high fluorescence brightness, stability, and uniformity. This nanofiber membrane is suitable for applications in flexible displays, flexible light emission, and anti-counterfeiting. The preparation method is simple, has a short process flow, is highly feasible, and is suitable for large-area preparation, offering advantages for industrialization.

[0074] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a mixed-dimensional perovskite nanofiber membrane with high fluorescence stability, characterized in that, The mixed-dimensional perovskite in the mixed-dimensional perovskite nanofiber membrane has the molecular formula (Al). m (A2) n-1 B n X 3n+1 This includes the following steps: S1. Prepare a perovskite solution and a polymer solution separately, and mix them evenly to obtain a spinning solution; the solutes in the perovskite solution are A1X, A2X and BX2, wherein A1 is one of phenylethylamine, butylamine, m-fluorophenylethylamine, and ethylenediamine, A2 is methylamine or formamidinium, B is one of Pb, Sn, and Bi, and X is one or more of I, Cl, and Br; the molar ratio of A1X to A2X is m:(n-1); m=1, 2, n=10~50; the molar ratio of A1X and A2X mixed with BX2 is 1:(0.8~1.2); S2. Inject the spinning solution from step S1 into a syringe and prepare a nanofiber membrane using electrospinning. S3. The nanofiber membrane obtained in step S2 is subjected to heat treatment and then naturally cooled to obtain a mixed-dimensional perovskite nanofiber membrane with high fluorescence stability. The heat treatment temperature is 50~140℃ and the time is 10 min~24 h.

2. The method for preparing a high fluorescence stability mixed-dimensional perovskite nanofiber membrane according to claim 1, characterized in that, In step S1, the concentration of the perovskite solution is 0.005~4.0 mmol / mL, and the solid content of the polymer solution is 5wt%~35wt%.

3. The method for preparing a high fluorescence stability mixed-dimensional perovskite nanofiber membrane according to claim 2, characterized in that, In the spinning solution, the volume ratio of the perovskite solution to the polymer solution is 1:(1~50).

4. The method for preparing a high fluorescence stability mixed-dimensional perovskite nanofiber membrane according to claim 1, characterized in that, In step S1, the solute in the polymer solution is one of polyvinylidene fluoride, polyurethane, and polyacrylonitrile, and the solvent is one or more of N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, and N-methylpyrrolidone.

5. The method for preparing a high fluorescence stability mixed-dimensional perovskite nanofiber membrane according to claim 1, characterized in that, In step S1, the solvent in the perovskite solution is one or more of N,N-dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, and N-methylpyrrolidone.

6. The method for preparing a high fluorescence stability mixed-dimensional perovskite nanofiber membrane according to claim 1, characterized in that, In step S2, the electrospinning voltage is 5~25 kV, the injection speed is 0.1~0.5 mm / min, and the receiving speed is 30~150 rpm / min.

7. A mixed-fiber perovskite nanofiber membrane with high fluorescence stability, characterized in that, The high fluorescence stability mixed-dimensional perovskite nanofiber membrane was prepared using the method described in any one of claims 1 to 6, wherein the mixed-dimensional perovskite in the mixed-dimensional perovskite nanofiber membrane has the molecular formula (Al). m (A2) n-1 B n X 3n+1 The mixed-dimensional perovskite is achieved by introducing raw materials in the form of organic amines; Wherein, A1 is one of phenylethylamine, butylamine, m-fluorophenylethylamine, and ethylenediamine; A2 is one of methylamine or formamidinium; B is one of Pb, Sn, and Bi; and X is one or more of I, Cl, and Br. The molar ratio of A1 to A2 is m:(n-1), where m=1 or 2, and n=10~50.

8. The high fluorescence stability mixed-dimensional perovskite nanofiber membrane according to claim 7, characterized in that, The diameter of the fibers in the mixed-dimensional perovskite nanofiber membrane is 50 nm to 4 μm; the photoluminescence quantum yield of the mixed-dimensional perovskite nanofiber membrane is not less than 45%.

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