A mixed-dimensional perovskite / polymer composite filament, and a preparation method and application thereof

Abstract

The application provides a mixed-dimensional perovskite / polymer composite filament, a preparation method and application. The preparation method comprises the following steps: firstly, uniformly mixing a mixed-dimensional perovskite solution and a polymer solution to obtain a spinning solution; then, preparing the mixed-dimensional perovskite / polymer composite filament by a wet spinning method; and finally, crystallizing the collected fiber by heat treatment, and obtaining the mixed-dimensional perovskite / polymer composite filament after natural cooling. The perovskite / polymer composite filament is prepared by mixing two-dimensional and three-dimensional perovskites, presents stable bright deep blue fluorescence and red fluorescence under UV light, and overcomes the technical defects of instability of the existing perovskite. Moreover, the perovskite / polymer composite filament has high photoluminescence quantum yield, high fluorescence stability, uniformity, good flexibility, stretchability and weavable integration, can be repeatedly recycled through simple dissolution and spinning, and has great application prospect in the fields of flexible display, flexible light emission, anti-counterfeiting and the like.

Description

Technical Field

[0001] This invention relates to the fields of wet spinning technology and photoluminescent fiber material preparation technology, and particularly to a mixed-fiber perovskite / polymer composite filament, its preparation method, and its application. Background Technology

[0002] Photoluminescent fibers are functional fibers that can produce fluorescence on their surface or inside when excited by ultraviolet light or laser. Due to their excellent stealth, camouflage, anti-counterfeiting, and fluorescent indication functions, photoluminescent fibers have been widely used in aerospace, flexible displays, process monitoring, and product anti-counterfeiting identification.

[0003] Perovskite nanocrystals possess excellent semiconductor properties, good light absorption, and extremely high luminescence performance, making them promising candidates for applications in solar cells, light-emitting diodes, lasers, and photodetectors. However, the hygroscopic and volatile nature of the organic cations in the perovskite nanocrystal structure leads to poor chemical stability under high humidity, prolonged light exposure, and high temperatures, resulting in a sharp decline in fluorescence performance and limiting their practical applications. Therefore, improving the stability of perovskite materials (water stability, thermal stability, and light stability, etc.) has become a prerequisite for their large-scale application.

[0004] As is well known, three-dimensional perovskite materials are prone to degradation when exposed to water, high humidity, or ultraviolet light, leading to their failure.

[0005] Chinese patent application CN109898235A discloses an ultra-stable organic-inorganic hybrid perovskite fiber film and its preparation method. CH3NH3PbX3 perovskite nanocrystals were synthesized in situ using electrospinning technology and uniformly dispersed in a polymer film with a fibrous morphology. The resulting CH3NH3PbX3 / Polymer composite film exhibits extremely high water resistance, heat resistance, and light stability. This film material can be widely used in the fabrication of LED devices with different color temperatures and color gamuts. However, the aforementioned fiber film suffers from technical drawbacks such as low mechanical strength, low tensile elasticity, low production efficiency, and poor recyclability.

[0006] In view of this, it is necessary to design an improved hybrid perovskite / polymer composite filament, its preparation method, and its application to solve the above problems. Summary of the Invention

[0007] The purpose of this invention is to provide a mixed-fiber perovskite / polymer composite filament, its preparation method, and its application.

[0008] To achieve the above-mentioned objective, this invention provides a method for preparing mixed-fiber perovskite / polymer composite filaments, comprising the following steps:

[0009] S1, Prepare a mixed-dimensional perovskite solution consisting of two-dimensional and three-dimensional perovskite;

[0010] S2, using uniaxial wet spinning method, a pre-defined ratio of mixed fiber perovskite solution and polymer solution are mixed evenly to obtain spinning solution, and then the spinning solution is extruded and injected into a coagulation bath. The soaking time in the coagulation bath is not more than 30 minutes, and the coagulation molding process is carried out to obtain composite fiber filament.

[0011] S3 involves heat-treating and crystallizing the initial composite fiber filament. After natural cooling, the internal structure of the initial composite fiber filament is reconstructed, forming a three-dimensional composite structure in which mixed-dimensional perovskite nanocrystals are uniformly distributed inside the porous fiber and on the porous pore walls. The mixed-dimensional perovskite / polymer composite filament is then collected.

[0012] As a further improvement of the present invention, the mixed-dimensional perovskite solution in step S1 is a mixed solution of A1X, A2X and BX2; wherein, A1 is one or more of phenylethylamine, butylamine, m-fluorophenylethylamine and ethylenediamine, A2 is one or more of methylamine, formamidinium and Cs, X = I, Cl or Br, and B = Pb, Sn or Bi.

[0013] As a further improvement of the present invention, the mixing ratio of A1X, A2X and BX2 is m:(n-1):n, where m=1,2; n=10~50, to obtain mixed-dimensional perovskite (A1). m (A2) n-1 B n X 3n+1 The additives are oleic acid and oleylamine.

[0014] As a further improvement of the present invention, the solvent of the mixed-dimensional perovskite solution in step S1 is one or more of DMF, DMSO, GBL, and NMP; the concentration of the mixed-dimensional perovskite solution is 0.005~4.0 mmol / mL.

[0015] As a further improvement of the present invention, the polymer in the polymer solution is one or more of polyurethane, polyacrylonitrile, polyvinyl chloride, and polyamide; the solvent in the polymer solution is one or more of DMF, DMSO, GBL, and NMP; and the concentration of the polymer solution is 5-30 wt%.

[0016] As a further improvement of the present invention, the volume ratio of the perovskite solution to the polymer solution in the spinning solution is 1:(1~50).

[0017] As a further improvement of the present invention, the extrusion speed of the uniaxial wet spinning method in step S2 is 0.1~1.0 mm / min; the coagulation bath is water, and the temperature of the coagulation bath is set to room temperature.

[0018] As a further improvement of the present invention, the heat treatment crystallization process in step S3 is as follows: the heat treatment temperature is lower than the melting point of the polymer, the heat treatment temperature is 50℃~140℃, and the heat treatment time is 10min~24h.

[0019] To achieve the above-mentioned objectives, the present invention also provides a mixed-dimensional perovskite / polymer composite filament prepared by the above-mentioned preparation method, which has a photoluminescence quantum yield of 35% or higher; its photoluminescence intensity decreases by less than 10% after being stored in air for one month; its photoluminescence intensity decreases by less than 10% after being stored at 85% relative humidity for one month; and its photoluminescence intensity decreases by less than 10% after being stored at a temperature below 50°C for one month.

[0020] To achieve the above-mentioned objectives, this invention also provides applications of the aforementioned mixed-fiber perovskite / polymer composite filaments in flexible displays, flexible light emission, anti-counterfeiting, organic dye detection, and sensing.

[0021] The beneficial effects of this invention are:

[0022] 1. The mixed-dimensional perovskite / polymer composite filament provided by this invention is prepared by mixing low-dimensional and three-dimensional perovskites. Under UV light irradiation, it exhibits stable, bright deep blue and red fluorescence, overcoming the technical defects of existing unstable perovskites. Furthermore, it possesses high photoluminescence quantum yield, high fluorescence stability, uniformity, good flexibility, stretchability, and weavability; it can be repeatedly recycled through simple dissolution and respinning.

[0023] 2. The method for preparing mixed-fiber perovskite / polymer composite filaments provided by the present invention is simple, has a short preparation process, is highly feasible, and is suitable for applications in flexible display, flexible light emission, anti-counterfeiting and other fields. Moreover, it is suitable for large-area preparation and has the advantage of industrialization.

[0024] 3. The mixed-fiber perovskite / polymer composite filament provided by this invention employs a heat treatment crystallization process to post-treat the solidified composite fiber filament. This process ensures the rapid and thorough removal of residual solvents, guarantees high-quality crystallization of the mixed-fiber perovskite, ensures the formation of a circular fiber cross-section, and ensures the fiber fully encapsulates the mixed-fiber perovskite nanocrystals. Furthermore, the heat treatment crystallization process can reconstruct the fiber structure of the composite fiber filament, creating a three-dimensional composite structure in which mixed-fiber perovskite nanocrystals are uniformly loaded within the fiber and on the pore walls of the nanoporous structure. This significantly enhances the performance of the composite filament, resulting in high tensile strength, high elongation ratio, good resilience, recyclability, and high production speed. In other words, the technical benefits of heat treatment crystallization include: constructing a nanoporous structure within the polymer fiber, enhancing perovskite crystallization, thereby significantly improving mechanical properties, achieving greater structural stability of the perovskite nanocrystals, increasing photoluminescence intensity, and shortening the production time of the composite filament. Attached Figure Description

[0025] Figure 1 The images show the mixed-fiber perovskite / polymer composite filaments provided in Example 1 of this invention under (a) natural light, (b) UV light, and (c) blue light.

[0026] Figure 2 This is a schematic diagram of the wet spinning process and a blue light display. Detailed Implementation

[0027] 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.

[0028] 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.

[0029] 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.

[0030] This invention provides a method for preparing mixed-fiber perovskite / polymer composite filaments, which includes the following steps:

[0031] S1, Prepare a mixed-dimensional perovskite solution consisting of two-dimensional and three-dimensional perovskite;

[0032] S2, using uniaxial wet spinning method, a pre-defined ratio of mixed fiber perovskite solution and polymer solution are mixed evenly to obtain spinning solution, and then the spinning solution is extruded and injected into a coagulation bath. The soaking time in the coagulation bath is not more than 30 minutes, and the coagulation molding process is carried out to obtain composite fiber filament.

[0033] S3 involves heat-treating and crystallizing the initial composite fiber filament. After natural cooling, the internal structure of the initial composite fiber filament is reconstructed, forming a three-dimensional composite structure in which mixed-dimensional perovskite nanocrystals are uniformly distributed inside the porous fiber and on the porous pore walls. The mixed-dimensional perovskite / polymer composite filament is then collected.

[0034] Preferably, the mixed-dimensional perovskite solution in step S1 is a mixed solution of A1X, A2X and BX2; wherein, A1 is one or more of phenylethylamine, butylamine, m-fluorophenylethylamine and ethylenediamine, A2 is one or more of methylamine, formamidinium and Cs, X = I, Cl or Br, and B = Pb, Sn or Bi.

[0035] Preferably, the mixing ratio of A1X, A2X and BX2 is m:(n-1):n, where m=1,2; n=10~50, to obtain mixed-dimensional perovskite (A1). m (A2) n-1 B n X 3n+1 The additives are oleic acid and oleylamine.

[0036] Preferably, the solvent of the mixed-dimensional perovskite solution in step S1 is one or more of DMF, DMSO, GBL, and NMP; the concentration of the mixed-dimensional perovskite solution is 0.005~4.0 mmol / mL.

[0037] Preferably, the polymer in the polymer solution is one or more of polyurethane, polyacrylonitrile, polyvinyl chloride, and polyamide; the solvent in the polymer solution is one or more of DMF, DMSO, GBL, and NMP; and the concentration of the polymer solution is 5-30 wt%.

[0038] Preferably, in the spinning solution, the volume ratio of the perovskite solution to the polymer solution is 1:(1~50).

[0039] Preferably, the extrusion speed of the uniaxial wet spinning method in step S2 is 0.1~1.0 mm / min; the coagulation bath is water, and the temperature of the coagulation bath is set to room temperature.

[0040] Preferably, the heat treatment crystallization process in step S3 is as follows: the heat treatment temperature is lower than the melting point of the polymer, the heat treatment temperature is 50℃~140℃, and the heat treatment time is 10min~24h.

[0041] Specifically, in this invention, the organic amines used to prepare mixed-dimensional perovskites have molecular formulas including, but not limited to, the following:

[0042] .

[0043] In this invention, a mixed-dimensional perovskite is prepared by adding a two-dimensional perovskite into a three-dimensional perovskite, which can achieve the stability of the perovskite and realize excellent and stable fluorescence function.

[0044] Example 1

[0045] Please see Figures 1 to 2 As shown, Example 1 of the present invention provides a method for preparing mixed-fiber perovskite / polymer composite filaments, comprising the following steps:

[0046] S1, prepare mixed-dimensional perovskite solution and polymer solution respectively:

[0047] Using a mixed solvent of DMF and DMSO (mixing ratio of 9:1), a mixed-dimensional perovskite (PEA2MA) was selected. 19 Pb 20 Cl 61 Specifically, A1X, A2X, and BX2 are PEACl, MACl, and PbCl2, respectively, and the concentration of the mixed-dimensional perovskite solution is 0.02 mmol / mL; the additives are oleic acid and oleylamine.

[0048] Using GBL as the solvent and TPU solution as the polymer solution, the concentration of the solution was 20 wt%.

[0049] S2, using a uniaxial wet spinning method, a perovskite solution and a polymer solution are mixed evenly to obtain a spinning solution (the volume ratio of the perovskite solution to the polymer solution in the spinning solution is 1:2.5). The spinning solution is then extruded and injected into a coagulation bath at room temperature. The soaking time in the coagulation bath is no more than 30 minutes for coagulation and molding treatment to obtain composite fiber filaments. The extrusion speed of the uniaxial wet spinning method in step S2 is 0.5 mm / min.

[0050] S3 involves heat-treating the initial composite fiber filaments for crystallization. The specific process is as follows: the initial composite fiber filaments are placed in an oven or heating cylinder and heated to ensure rapid and thorough removal of residual solvents. Suitable heat treatment conditions (70℃ for 0.5 hours) ensure high-quality perovskite crystallization, guaranteeing the formation of a circular fiber cross-section and sufficient coating of perovskite nanocrystals (excessive temperature can cause fiber collapse, partial dissolution, and perovskite degradation). After natural cooling, the mixed-fiber perovskite / polymer composite filament – ​​PEA2MA – is collected. 19 Pb 20 Cl 61 / TPU composite filament.

[0051] After performance testing, the hybrid perovskite / polymer composite filament (PEA2MA) was found to be... 19 Pb 20 Cl 61 / TPU) photoluminescence quantum yield (PLQY) is 50%; its photoluminescence intensity decreases by 6% after one month of storage in air; it decreases by 8% after one month of storage at 85% relative humidity; at 50 o After being stored at temperatures below 30°C for one month, the photoluminescence intensity decreased by 8%.

[0052] Example 2

[0053] Example 2 of this invention provides a method for preparing mixed-fiber perovskite / polymer composite filaments, comprising the following steps:

[0054] S1, prepare mixed-dimensional perovskite solution and polymer solution respectively:

[0055] Using DMF as a solvent, mixed-dimensional perovskite (BA2MA) was selected. 14 Pb 15 I 46 Specifically, A1X, A2X, and BX2 are BAI, MAI, and PbI2, respectively, and the concentration of the mixed perovskite solution is 0.02 mmol / mL; the additives are oleic acid and oleylamine.

[0056] DMF was used as the solvent, and TPU solution was selected as the polymer solution with a concentration of 20 wt%.

[0057] S2, using a uniaxial wet spinning method, the perovskite solution and the polymer solution are mixed evenly to obtain a spinning solution (the volume ratio of the perovskite solution to the polymer solution in the spinning solution is 1:2.5). Then, the spinning solution is extruded and injected into a coagulation bath at room temperature. The soaking time in the coagulation bath is not more than 30 minutes, and the coagulation molding process is carried out to obtain composite fiber filament.

[0058] S3 involves heat-treating the initial composite fiber filaments for crystallization. The specific process is as follows: the initial composite fiber filaments are placed in an oven or heating cylinder and heated to ensure rapid and thorough removal of residual solvents. Suitable heat treatment conditions (80℃ for 6 hours) guarantee high-quality perovskite crystallization, ensuring the fiber filaments form a circular cross-section and that the fibers fully encapsulate the perovskite nanocrystals (excessive temperature can cause fiber collapse, partial dissolution, and perovskite degradation). After natural cooling, the mixed-fiber perovskite / polymer composite filaments are collected.

[0059] After performance testing, the hybrid perovskite / polymer composite filament (BA2MA) was found to be... 14Pb 15 I 46 The photoluminescence quantum yield (PLQY) of the TPU was 43%; the photoluminescence intensity decreased by 9.2% after one month of storage in air; the photoluminescence intensity decreased by 9.5% after one month of storage at 85% relative humidity; and the photoluminescence intensity decreased by 50% after one month of storage at 50% relative humidity. o After being stored at temperatures below 30°C for one month, the photoluminescence intensity decreased by 9.5%.

[0060] Please see Figure 1 As shown, when the mixed-fiber perovskite / polymer composite filaments prepared in Examples 1-2 are embroidered on fabric, they can display different letters under (a) natural light, (b) UV light, and (c) blue light.

[0061] Comparative Example 1

[0062] TPU filament was used as a blank control example.

[0063] Comparative Example 2

[0064] The difference from Example 1 is that no low-dimensional perovskite is added, and the perovskite solution contains only three-dimensional perovskite.

[0065] Comparative Example 3

[0066] The difference from Example 1 is that the heat treatment in step S3 is not performed, and the composite fiber filament is prepared.

[0067] Comparative Example 4

[0068] The difference from Example 1 is that the heat treatment in step S3 is replaced with a tensile heat treatment.

[0069] By comparing the mechanical properties of Example 1 and Comparative Example 1, it was found that the addition of perovskite nanocrystals can improve the mechanical properties of the fibers.

[0070] By comparing the performance of Example 1 and Comparative Example 2, it was found that the simple three-dimensional perovskite and polymer composite filament prepared in Comparative Example 2 had the technical problem of unstable fluorescence performance. However, the mixed-dimensional perovskite and polymer composite filament prepared in Example 1, based on the mixing of two-dimensional and three-dimensional perovskite, made the perovskite more stable. Therefore, its fluorescence stability was significantly higher than that of Comparative Example 2.

[0071] By comparing the performance of Example 1 and Comparative Example 3, the heat treatment crystallization process can simultaneously and significantly improve both photoluminescence and mechanical properties. This is mainly because: heat treatment at a specific temperature allows for complete crystallization of the perovskite, and well-crystallized perovskite can achieve excellent photoluminescence properties. Furthermore, it completely removes residual solvent molecules, stabilizing the polymer structure to a certain extent. Moreover, heat treatment crystallization can construct a nanoporous three-dimensional structure within the fiber, allowing perovskite nanocrystals to be uniformly dispersed on the pore walls of the porous structure and inside the nanofiber. This significantly enhances the mechanical and strain properties of the composite filament, while also making the perovskite nanocrystal structure more stable, increasing photoluminescence intensity, and shortening the production time of the composite filament.

[0072] A comparison of the performance of Example 1 and Comparative Example 4 shows that the heat treatment process of the present invention can significantly improve the photoluminescence and mechanical properties, while conventional hot stretching treatment reduces the photoluminescence and mechanical properties of the fiber. This is mainly because perovskite is uniformly distributed inside the fiber, and the content of perovskite nanocrystals per unit length decreases accordingly after stretching, thus reducing the photoluminescence brightness. On the other hand, under the same stretching conditions, the smaller the fineness of the same fiber, the lower the mechanical properties.

[0073] Examples 3-4

[0074] The difference from Example 1 is that the mixing ratio of each raw material in the mixed perovskite is different, but everything else is the same as in Example 1, and will not be repeated here.

[0075]

[0076] The effect of the mixing ratio of various raw materials in the perovskite blend on the properties of the composite filament is as follows: as the ratio increases, PLQY is enhanced, while tensile deformation and tensile strength do not change significantly.

[0077] Examples 5-6

[0078] The difference from Example 1 is that the concentration and ratio of the mixed-dimensional perovskite and the polymer are different, but everything else is the same as in Example 1, and will not be repeated here.

[0079]

[0080] The effect of the ratio of perovskite to polymer on the properties of composite filaments is as follows: with the increase of polymer concentration or the increase of polymer addition ratio, the fluorescence performance PLQY of composite filaments will decrease appropriately, while the maximum tensile change rate and tensile strength change rate are not significant.

[0081] Examples 9-10

[0082] The difference from Example 1 is that the types of raw materials (A1X, A2X and BX2) in the mixed perovskite solution are different, but everything else is the same as in Example 1, and will not be repeated here.

[0083]

[0084] The effects of the raw material types (A1X, A2X, and BX2) of the mixed-fiber perovskite solution on the properties of the composite filaments are as follows: organic amines have no significant effect on the PLQY and mechanical properties of the composite filaments. When X is Cl, it exhibits blue fluorescence; when X is I, it exhibits red fluorescence.

[0085] Examples 11-14

[0086] The difference from Example 1 is that the heat treatment temperature and time are different, but everything else is the same as Example 1, and will not be repeated here.

[0087]

[0088] The effect of heat treatment crystallization process parameters on the properties of composite filaments is as follows: appropriate heat treatment temperature and time are necessary to obtain good fluorescence and mechanical properties. Temperatures that are too high or too low will lead to a decrease in fluorescence (PLQY) and mechanical properties.

[0089] Examples 15-16

[0090] The difference from Example 1 is that the extrusion speed of the uniaxial wet spinning method is different; otherwise, it is the same as Example 1 and will not be repeated here.

[0091]

[0092] The effect of extrusion speed setting on the properties of composite filaments in uniaxial wet spinning is as follows: the spinning speed has no significant effect on fluorescence properties. Increasing the spinning speed reduces the diameter of the composite filament and appropriately decreases the mechanical properties; decreasing the spinning speed increases the diameter of the composite filament and appropriately increases the mechanical properties.

[0093] In summary, this invention provides a mixed-dimensional perovskite / polymer composite filament and its preparation method. The preparation method first involves uniformly mixing a mixed-dimensional perovskite solution with a polymer solution to obtain a spinning solution. Then, a wet spinning method is used to prepare the mixed-dimensional perovskite / polymer composite filament. The collected fibers are then crystallized through heat treatment, and after natural cooling, the mixed-dimensional perovskite / polymer composite filament is obtained. This perovskite / polymer composite filament, prepared from a mixture of low-dimensional and three-dimensional perovskites, exhibits stable, bright deep blue and red fluorescence under UV light, overcoming the technical defects of unstable perovskites in existing technologies. Furthermore, this perovskite / polymer composite filament possesses high photoluminescence quantum yield, high fluorescence stability, uniformity, good flexibility, stretchability, and weavability; it can be repeatedly recycled through simple dissolution and respinning.

[0094] 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 of making a hybrid perovskite / polymer composite filament, the method comprising: Includes the following steps: ​ S1, Prepare a mixed-dimensional perovskite solution consisting of two-dimensional and three-dimensional perovskite; S2, using uniaxial wet spinning method, a pre-defined ratio of mixed fiber perovskite solution and polymer solution are mixed evenly to obtain spinning solution, and then the spinning solution is extruded and injected into a coagulation bath. The soaking time in the coagulation bath is not more than 30 minutes, and the coagulation molding process is carried out to obtain composite fiber filament. S3, the composite fiber filament is heat-treated and crystallized. After natural cooling, the internal structure of the composite fiber filament is reconstructed, forming a three-dimensional composite structure in which mixed-dimensional perovskite nanocrystals are uniformly distributed inside the porous fiber and on the porous pore walls. The mixed-dimensional perovskite / polymer composite filament is collected. The mixed-dimensional perovskite solution mentioned in step S1 is a mixed solution of A1X, A2X and BX2; wherein, A1 is one or more of phenylethylamine, butylamine, m-fluorophenylethylamine, and ethylenediamine; A2 is one or more of methylamine, formamidinium, and Cs; X is one or more of I, Cl, and Br; and B is one or more of Pb, Sn, and Bi. The mixing ratio of A1X, A2X, and BX2 is m:(n-1):n, where m=1,2; n=10~50, resulting in a mixed-dimensional perovskite (A1). m (A2) n-1 B n X 3n+1 The additives are oleic acid and oleylamine. The heat treatment crystallization process described in step S3 is as follows: the heat treatment temperature is lower than the melting point of the polymer, the heat treatment temperature is 50℃~140℃, and the heat treatment time is 10min~24h.

2. The method for preparing a mixed-fiber perovskite / polymer composite filament according to claim 1, characterized in that: The solvent of the mixed-dimensional perovskite solution in step S1 is one or more of DMF, DMSO, GBL, and NMP; the concentration of the mixed-dimensional perovskite solution is 0.005~4.0 mmol / mL.

3. The method for preparing a mixed-fiber perovskite / polymer composite filament according to claim 1, characterized in that: The polymer in the polymer solution is one or more of polyurethane, polyacrylonitrile, polyvinyl chloride, and polyamide; the solvent in the polymer solution is one or more of DMF, DMSO, GBL, and NMP; and the concentration of the polymer solution is 5-30 wt%.

4. The method for preparing a mixed-fiber perovskite / polymer composite filament according to claim 1, characterized in that: In the spinning solution, the volume ratio of the perovskite solution to the polymer solution is 1:(1~50).

5. The method for preparing a mixed-fiber perovskite / polymer composite filament according to claim 1, characterized in that: In step S2, the extrusion speed of the uniaxial wet spinning method is 0.1~1.0 mm / min; the coagulation bath is water, and the temperature of the coagulation bath is set to room temperature.

6. A mixed-dimensional perovskite / polymer composite filament prepared by the method for preparing a mixed-dimensional perovskite / polymer composite filament according to any one of claims 1 to 5, characterized in that: The photoluminescence quantum yield of the hybrid perovskite / polymer composite filament reaches 35% or higher; the photoluminescence intensity decreases by less than 10% after one month of storage in air; the photoluminescence intensity decreases by less than 10% after one month of storage at 85% relative humidity; and the photoluminescence intensity decreases by less than 10% after one month of storage at a temperature below 50°C.

7. Use of the hybrid perovskite / polymer composite filaments according to claim 6, characterized in that: The hybrid perovskite / polymer composite filaments have applications in flexible displays, flexible light emission, anti-counterfeiting, organic dye detection, and sensing.

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