Multicolor electroluminescent fiber and electrospinning preparation method thereof

Abstract

The application discloses a kind of multicolor electroluminescent fiber and its electrostatic spinning preparation method, the preparation method includes the following steps: (1) electrostatic spinning preparation light-emitting layer: by electrostatic spinning, electroluminescent material is loaded to the surface of conductive fiber;(2) dyeing preparation color conversion layer: the fiber loaded with electroluminescent material is immersed into fluorescent dye solution, so that the surface of fiber is dyed with color to form color conversion layer;(3) dip coating preparation dielectric layer: after the fiber of fluorescent dyeing is dyed, it is immersed into PDMS diluent to prepare dielectric layer;(4) build outer electrode: outer electrode is loaded on the surface of dielectric layer in the form of winding or coating;(5) insulation packaging: finally, coating transparent insulating polymer is packaged.The application method is by introducing different color fluorescent dye to widen the color of electroluminescent fiber, and has higher application value in the field of intelligent clothing and pattern decoration.The preparation process is simple, mild, low in cost, and suitable for industrial production.

Description

Technical Field

[0001] The present invention belongs to the technical field of wearable smart clothing, and specifically relates to a multi-color electroluminescent fiber and an electrostatic spinning preparation method thereof. Background Art

[0002] In recent years, wearable electronics have attracted widespread attention due to their advantages such as lightness, flexibility, portability, and low power consumption. By combining multiple functional materials through physical or chemical methods, wearable electronic devices can possess various basic functions such as light emission, thermal management, power generation, and sensing. Traditional planar and thin-film wearable electronics exhibit excellent and stable optoelectronic properties, but lack breathability and comfort. In contrast, emerging wearable electronics based on functional fibers have become more attractive, with advantages such as flexible wearability, good wearability, scalable preparation, and multifunctional integration.

[0003] Among the wide range of functional fiber electronics, electroluminescent fibers have been extensively studied for various applications, including wearable and portable lighting, displays, and signage. For example, smart wearable luminescent textiles are being developed to manufacture traffic safety vests to prevent nighttime traffic accidents. In addition, wearable luminescent textiles can also be used for fabric displays and entertainment decorations. Although electroluminescent fibers enable the integration of functional luminescent fibers into textiles through knitting, weaving, or braiding, electroluminescent fibers are only available in a small number of colors due to the limited variety of electroluminescent materials.

[0004] From an application perspective, various color expression techniques could broaden the application areas of AC electroluminescent fibers. Although color tuning has been reported by mixing different colored luminescent powders or varying dopant concentrations, these methods still only achieve a narrow range of color adjustment. Therefore, there is a need to develop a feasible and universal method for expressing a wider range of colors to meet the color demands of practical applications. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the present invention provides a multi-color electroluminescent fiber and an electrostatic spinning preparation method thereof.

[0006] The present invention is achieved through the following technical solutions:

[0007] A method for preparing multi-color electroluminescent fibers by electrospinning, the method comprising the following steps:

[0008] (1) Preparation of the luminescent layer by electrospinning: an electroluminescent material, a solvent, and a polymer as a binder are mixed and stirred to obtain a luminescent spinning solution. The electroluminescent material is loaded onto the surface of the conductive fiber by electrospinning to obtain a conductive fiber with a luminescent layer.

[0009] The electroluminescent material is selected from one or more of zinc sulfide-doped luminescent powders ZnS:Mn, ZnS:Cl, ZnS:Cu, ZnS:Sm, ZnS:Tm, ZnS:Cu,Cl and ZnS:Mn,Cu,Cl, and the mass ratio of the electroluminescent material to the polymer is (1-5):1;

[0010] (2) Preparation of color conversion layer by dyeing: The conductive fiber with the luminescent layer is dipped into the fluorescent dye solution to dye the fiber surface, and the color conversion layer is formed after drying;

[0011] (3) Dip coating to prepare the dielectric layer: The conductive fiber dyed with fluorescent dye is immersed in the PDMS diluent, then slowly pulled out at a uniform speed, and dried to obtain a uniformly loaded dielectric layer;

[0012] The PDMS diluent is prepared by mixing PDMS and n-hexane in a mass ratio of 1:(1-5);

[0013] (4) constructing an external electrode: loading the external electrode onto the surface of the dielectric layer by winding or coating to obtain an electroluminescent fiber;

[0014] (5) Insulation packaging: A transparent insulating polymer is coated on the outside of the electroluminescent fiber, and after drying, a multi-color electroluminescent fiber with a transparent packaging layer as the outermost layer is obtained.

[0015] Preferably, the electroluminescent material is one or more of ZnS:Mn, ZnS:Cl, ZnS:Cu, ZnS:Cu,Cl, and ZnS:Mn,Cu,Cl; and the mass ratio of the electroluminescent material to the polymer is (2-4):1. Optimally, the mass ratio of the ZnS:Cu luminescent powder to polyvinylidene fluoride-hexafluoropropylene is 3:1.

[0016] Preferably, in the PDMS dilution solution, the mass ratio of PDMS to n-hexane is 1:(2-4). The most optimal mass ratio of PDMS to n-hexane is 1:(3-4).

[0017] Preferably, in step (1),

[0018] The conductive fibers include one or more of metal conductive fibers, metal particle-plated chemical fibers, carbon fibers, ion gel fibers, and conductive polymer composite fibers;

[0019] The particle size of the electroluminescent material is 10 to 50 μm, preferably 10 to 30 μm;

[0020] The solvent is a mixture of N,N-dimethylformamide and acetone in a mass ratio of (1-2):1;

[0021] The polymer is selected from one of styrene-butadiene-styrene, polyurethane, and polyvinylidene fluoride-hexafluoropropylene;

[0022] Preferably, in step (1),

[0023] The steps of preparing the luminescent spinning solution are: first preparing a polymer into a polymer solution with a solid content of 10% to 20%, then adding an electroluminescent material and mixing to obtain the luminescent spinning solution.

[0024] Preferably, in step (1), the process parameters of electrospinning are: flow rate 0.3-1.5 mL / hr, rotation speed 140-260 rpm, and moving speed 0.5-2.5 mm / s.

[0025] Preferably, in step (2), the fluorescent dye is one or more of cyanine dyes, rhodamine dyes, fluorescein dyes, coumarins and their derivatives, benzanthrone dyes, nelcarboxylic acid derivatives, anthraquinone derivatives, and naphthoquinone derivatives.

[0026] Preferably, in step (2), the drying conditions are: temperature 60-100° C., time 5-10 min; in step (3), the drying conditions are: temperature 80-120° C., time 15-30 min.

[0027] Preferably, in step (4), the external electrode comprises a metal wire or metal particles, the metal wire comprises a silver wire, a copper wire, a silver-plated copper wire, a steel wire, a titanium wire or a tungsten wire, and the metal particles comprise a conductive silver paste, a silver nanowire, a copper nanowire or a silver nanowire.

[0028] Preferably, when the outer electrode is prepared by a winding method, the pitch is 0.2 to 0.8 mm;

[0029] When the coating method is used to load the external electrode, the surface of the dielectric layer needs to be plasma treated to improve the hydrophilicity. The plasma treatment power is 100-150W, the treatment time is 1-5 minutes, and then the conductive solution is dipped in it. The dipping time is 5-30 seconds and the number of dipping times is 2-5 times. After dipping, it is dried at a temperature of 60-150°C, preferably 80-100°C.

[0030] Preferably, in step (5), the insulating polymer is one or more of epoxy resin, acrylate resin, polyurethane resin, polytetrafluoroethylene resin, polyvinylidene fluoride resin, or silicone resin; and the drying conditions are: temperature 80-150°C, time 20-40 minutes. The most preferred insulating polymer is one or more of epoxy resin, polyurethane resin, polyvinylidene fluoride resin, or silicone resin.

[0031] A multicolor electroluminescent fiber prepared by the preparation method of the present invention comprises, from the inside out, a conductive fiber, a luminescent layer, a color conversion layer, a dielectric layer, and an encapsulation layer. The outer surface of the dielectric layer is wrapped or coated with an external electrode, which is a metal wire or metal particle. (1) The conductive fiber serves as the fiber base electrode; (2) The luminescent layer is a functional layer that produces electroluminescence; (3) The color conversion layer utilizes the light absorption and emission characteristics of the fluorescent dye to perform color processing on the electroluminescence; (4) The dielectric layer prevents short circuits in the device; (5) The external electrode, together with the fiber base electrode, provides the electric field required for electroluminescence; and (6) The transparent encapsulation layer serves to insulate and protect the electroluminescent fiber.

[0032] Compared with the prior art, the present invention has the following positive effects:

[0033] (1) The method of the present invention changes the color of electroluminescent fibers by introducing fluorescent dyes of different colors, thereby significantly broadening the range of luminescent colors and having high application value in the fields of smart clothing and pattern decoration;

[0034] (2) The process of the present invention combines electrospinning and solution coating, and can realize the continuous preparation of electroluminescent fibers through equipment assembly and modification. Moreover, the technology is simple, efficient, mild, low-cost, green and environmentally friendly, and suitable for industrial production;

[0035] (3) The electroluminescent fiber of the present invention has good flexibility, good brightness, and excellent mechanical properties, and can be knitted, woven, braided, sewn, embroidered, etc. using industrial textile equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the electroluminescent fiber structure of the present invention;

[0037] Figure 2 It is a purple electroluminescent fiber;

[0038] Figure 3 It is a green electroluminescent fiber;

[0039] Figure 4 It is a blue electroluminescent fiber;

[0040] Figure 5 The effect of the mass ratio of n-hexane to PDMS on the brightness of the luminescent fiber;

[0041] Figure 6 The effect of the mass ratio of electroluminescent material to polymer on the brightness of luminescent fibers;

[0042] Figure 7 It is an electroluminescent fiber without silver nanowire external electrodes;

[0043] Figure 8This is a photo of the embroidered luminous LOGO on the jacket. DETAILED DESCRIPTION

[0044] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0045] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0046] The present invention will now be further described in conjunction with specific examples. The following examples are only intended to explain the present invention but do not limit the present invention. The test samples and test procedures used in the following examples include the following (if the specific experimental conditions are not specified in the examples, they are usually based on conventional conditions or the conditions recommended by the reagent company; the reagents, consumables, etc. used in the following examples, unless otherwise specified, can be obtained from commercial sources).

[0047] The structural diagram of the electroluminescent fiber of the present invention is shown in FIG. Figure 1 The multi-color electroluminescent fiber includes a conductive fiber, a light-emitting layer, a color conversion layer, a dielectric layer and an encapsulation layer from the inside to the outside. The outer surface of the dielectric layer is wrapped or coated with an external electrode, which is a metal wire or metal particle.

[0048] Example 1 (color conversion layer is Rhodamine B dye solution)

[0049] A multi-color electroluminescent fiber, the preparation method of which comprises the following steps:

[0050] (1) Preparation of the luminescent layer by electrospinning: First, N,N-dimethylformamide and acetone (mass ratio 1.5:1) were mixed as solvent to prepare a polyvinylidene fluoride-hexafluoropropylene solution with a solid content of 10%. ZnS:Cu luminescent powder was then added according to a mass ratio of ZnS:Cu to polyvinylidene fluoride-hexafluoropropylene of 2:1, and the mixture was stirred to obtain a luminescent spinning solution. The electroluminescent material was loaded onto the surface of the silver-plated nylon fiber by electrospinning. The spinning process parameters were: flow rate 0.8 mL / hr, rotation speed 160 rpm, and movement speed 1.0 mm / s.

[0051] (2) Preparation of color conversion layer by dyeing: The fiber loaded with electroluminescent material was immersed in rhodamine B dye solution to dye the fiber surface, and then dried at 80°C for 8 minutes to completely evaporate the solvent.

[0052] (3) Dip coating to prepare the dielectric layer: prepare a PDMS dilution solution composed of PDMS and n-hexane in a mass ratio of 1:2, immerse the fluorescent dye-dyed fiber in the PDMS dilution solution, then slowly pull it out at a uniform speed, and dry it at 100°C for 20 min to obtain a uniformly loaded dielectric layer.

[0053] (4) Construction of external electrodes: Copper wire (0.05 mm in diameter) was wound around the dielectric layer at a pitch of 0.4 mm, and then plasma treated (100 W, 2 min). The fibers were then immersed in a silver nanowire dispersion for 10 s, taken out and dried at 80 °C. This process was repeated five times to form a uniformly distributed silver nanowire external electrode on the surface of the dielectric layer.

[0054] (5) Insulation packaging: Silicone resin is coated on the outside of the electroluminescent fiber and dried at 100°C for 30 minutes to obtain a transparent packaging layer.

[0055] The prepared electroluminescent fibers Figure 2 As shown, after applying an AC driving voltage, it emits purple light (the superposition of the blue light of the ZnS:Cu luminescent powder and the red light of Rhodamine B), and can still work stably and normally after bending, compression, and water washing.

[0056] Example 2 (color conversion layer is fluorescent yellow 3G dye solution)

[0057] A multi-color electroluminescent fiber, the preparation method of which comprises the following steps:

[0058] (1) Preparation of the luminescent layer by electrospinning: First, N,N-dimethylformamide and acetone (mass ratio 1.5:1) were mixed as solvent to prepare a polyvinylidene fluoride-hexafluoropropylene solution with a solid content of 10%. ZnS:Cu luminescent powder was then added according to a mass ratio of ZnS:Cu to polyvinylidene fluoride-hexafluoropropylene of 2:1, and the mixture was stirred to obtain a luminescent spinning solution. The electroluminescent material was loaded onto the surface of the silver-plated nylon fiber by electrospinning. The spinning process parameters were: flow rate 0.8 mL / hr, rotation speed 160 rpm, and movement speed 1.0 mm / s.

[0059] (2) Preparation of color conversion layer by dyeing: The fiber loaded with electroluminescent material was immersed in fluorescent yellow 3G dye solution to dye the fiber surface, and then dried at 80°C for 8 minutes to completely evaporate the solvent.

[0060] (3) Dip coating to prepare the dielectric layer: prepare a PDMS dilution solution composed of PDMS and n-hexane in a mass ratio of 1:2, immerse the fluorescent dye-dyed fiber in the PDMS dilution solution, then slowly pull it out at a uniform speed, and dry it at 100°C for 20 min to obtain a uniformly loaded dielectric layer.

[0061] (4) Construction of external electrodes: Copper wire (0.05 mm in diameter) was wound around the dielectric layer at a pitch of 0.4 mm, and then plasma treated (100 W, 2 min). The fibers were then immersed in a silver nanowire dispersion for 10 s, taken out and dried at 80 °C. This process was repeated five times to form a uniformly distributed silver nanowire external electrode on the surface of the dielectric layer.

[0062] (5) Insulation packaging: Silicone resin is coated on the outside of the electroluminescent fiber and dried at 100°C for 30 minutes to obtain a transparent packaging layer.

[0063] The prepared electroluminescent fibers Figure 3 As shown, after applying an AC driving voltage, it emits green light (the superposition of the blue light of the ZnS:Cu luminescent powder and the yellow light of the fluorescent yellow 3G), and can still work stably and normally after bending, compression, and water washing.

[0064] Example 3 (Single-factor experiment on the effect of PDMS dilution ratio on the brightness of luminescent fibers)

[0065] A blue electroluminescent fiber, the preparation method thereof comprises the following steps:

[0066] (1) Preparation of the luminescent layer by electrospinning: First, N,N-dimethylformamide and acetone (mass ratio 1.5:1) were mixed as solvent to prepare a polyvinylidene fluoride-hexafluoropropylene solution with a solid content of 10%. ZnS:Cu luminescent powder was then added according to a mass ratio of ZnS:Cu to polyvinylidene fluoride-hexafluoropropylene of 3:1, and the mixture was stirred to obtain a luminescent spinning solution. The electroluminescent material was loaded onto the surface of the silver-plated nylon fiber by electrospinning. The spinning process parameters were: flow rate 0.5 mL / hr, rotation speed 190 rpm, and movement speed 1.4 mm / s.

[0067] (2) Dip-coating the dielectric layer: PDMS dilutions were prepared, each consisting of PDMS and n-hexane in a mass ratio of 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, and 1:4. The fiber was immersed in each of the PDMS dilutions, then slowly pulled out at a uniform speed and dried at 100°C for 20 min to obtain a uniformly loaded dielectric layer.

[0068] (3) Construction of external electrodes: Copper wire (0.05 mm in diameter) was wound around the dielectric layer at a pitch of 0.4 mm, and then plasma treated (100 W, 2 min). The fibers were then immersed in a silver nanowire dispersion for 10 s, taken out and dried at 80 °C. This process was repeated five times to form a uniformly distributed silver nanowire external electrode on the surface of the dielectric layer.

[0069] (4) Insulation packaging: Silicone resin is coated on the outside of the electroluminescent fiber and dried at 100°C for 30 minutes to obtain a transparent packaging layer.

[0070] The prepared electroluminescent fibers Figure 4 As shown, no color conversion layer was added during the preparation process. After applying an AC driving voltage, blue light was emitted (only the ZnS:Cu luminescent powder emitted light, and color conversion was not achieved). It can still work stably and normally after bending, compression, and water washing.

[0071] The brightness of the luminescent fibers made from PDMS dilutions with different PDMS and n-hexane mass ratios was tested. Figure 5 .according to Figure 5 The results show that a PDMS / n-hexane mass ratio of 1:2-4 is relatively bright. The optimal ratio is 1:3-4. The luminescent fiber has the highest brightness when the PDMS / n-hexane mass ratio is 1:3.

[0072] Example 4 (Single-factor experiment on the effect of electroluminescent material doping ratio on the brightness of luminescent fiber)

[0073] A blue electroluminescent fiber, the preparation method thereof comprises the following steps:

[0074] (1) Preparation of the luminescent layer by electrospinning: First, N,N-dimethylformamide and acetone (mass ratio 1.5:1) were mixed as solvent to prepare a polyvinylidene fluoride-hexafluoropropylene solution with a solid content of 10%. ZnS:Cu luminescent powder was then added to the polyvinylidene fluoride-hexafluoropropylene solution and mixed. After stirring, a luminescent spinning solution was obtained. Luminescent spinning solutions with a mass ratio of 1:1, 2:1, 3:1, and 4:1 of electroluminescent material ZnS:Cu luminescent powder to polymer polyvinylidene fluoride-hexafluoropropylene were prepared respectively. Electrospinning was performed using the luminescent spinning solutions with different ratios. The electroluminescent material was loaded onto the surface of the silver-plated nylon fiber by electrospinning. The spinning process parameters were: flow rate 0.5 mL / hr, rotation speed 190 rpm, and moving speed 1.4 mm / s.

[0075] (2) Dip coating to prepare the dielectric layer: prepare a PDMS dilution solution composed of PDMS and n-hexane in a mass ratio of 1:2.5, immerse the fiber in the PDMS dilution solution, then slowly pull it out at a uniform speed, and dry it at 100°C for 20 min to obtain a uniformly loaded dielectric layer.

[0076] (3) Construction of external electrodes: Copper wire (0.05 mm in diameter) was wound around the dielectric layer at a pitch of 0.4 mm, and then plasma treated (100 W, 2 min). The fibers were then immersed in a silver nanowire dispersion for 10 s, taken out and dried at 80 °C. This process was repeated five times to form a uniformly distributed silver nanowire external electrode on the surface of the dielectric layer.

[0077] (4) Insulation packaging: Silicone resin is coated on the outside of the electroluminescent fiber and dried at 100°C for 30 minutes to obtain a transparent packaging layer.

[0078] No color conversion layer was added during the preparation process. After applying an AC driving voltage, it exhibits blue light (only the ZnS:Cu luminescent powder emits light, and color conversion is not achieved). It can still work stably and normally after bending, compression, and washing.

[0079] The brightness of the luminescent fiber was tested when the mass ratio of electroluminescent material ZnS:Cu luminescent powder to polymer polyvinylidene fluoride-hexafluoropropylene was 1:1, 2:1, 3:1, and 4:1. Figure 6 .from Figure 6 The data show that the brightness of the luminescent fiber is the highest when the ratio of electroluminescent material to polymer is 3:1.

[0080] Comparative Example 1 (External Electrode Without Wrapped Metal Wire)

[0081] The difference from Example 2 is: (4) Construction of the external electrode: the fiber loaded with the dielectric layer was first plasma treated (100 W, 2 min), and then immersed in the silver nanowire dispersion for 10 s, taken out and dried at 80°C. After repeating 5 times, a uniformly distributed silver nanowire external electrode was formed on the surface of the dielectric layer.

[0082] The electroluminescent fiber produced was not wrapped with a metal wire outer electrode during the manufacturing process. When an AC driving voltage was applied, it emitted a green light. However, the continuous conductive layer formed by the silver nanowires, which served as a single outer electrode, was unstable and easily broke during bending, compression, and washing, causing the electroluminescent fiber to fail. Without the metal wire outer electrode during the manufacturing process, the electroluminescent fiber produced was unstable and could not meet the requirements of use.

[0083] Comparative Example 2 (no dielectric layer)

[0084] The difference from Example 2 is that after the color conversion layer is prepared by dip-dyeing, no dielectric layer loading is performed, and the external electrode is directly constructed to prepare the electroluminescent fiber.

[0085] The fabricated EL fiber lacks a dielectric layer, and without the dielectric layer protecting the inner and outer electrodes, the device suffers from poor stability. During operation, the device is prone to breakdown, causing the inner and outer electrodes to connect, resulting in a short circuit and fiber failure. Without a dielectric layer during fabrication, the resulting EL fiber is unstable and cannot be mass-produced.

[0086] Comparative Example 3 (Uncoated Silver Nanowire External Electrode)

[0087] The difference from Example 2 is that there is no fluorescent yellow 3G dye color conversion layer; (4) Construction of external electrode: Copper wire (diameter 0.05 mm) is wound around the dielectric layer at a pitch of 0.4 mm.

[0088] The prepared electroluminescent fibers Figure 7 As shown, the fiber surface is not coated with silver nanowire external electrodes. When an AC driving voltage is applied, only a faint blue light is emitted around the metal wire. Because the conductive area formed by the metal wire as a single external electrode on the fiber surface cannot cover the fiber surface, uniform light emission cannot be achieved on the surface of the electroluminescent fiber. Without the silver nanowire external electrode coating, uniform and bright light emission from the fiber cannot be achieved, and the prepared electroluminescent fiber will have no practical application value.

[0089] The method of the present invention broadens the color of electroluminescent fibers by introducing fluorescent dyes of different colors, and has high application value in the fields of smart clothing and pattern decoration. The photo of the embroidered luminous LOGO on the jacket made of the fiber of the present invention is shown in the figure. Figure 8 The preparation process is simple, the conditions are mild, the cost is low, and it is suitable for industrial production.

[0090] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from the other embodiments. Reference can be made to the descriptions of the identical or similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple, and the relevant parts can be referred to the descriptions of the methods.

[0091] The above is a detailed introduction to the multi-color electroluminescent fiber and the electrospinning preparation method thereof provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only intended to help understand the method and core concept of the present invention. It should be noted that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing multi-color electroluminescent fibers by electrospinning, characterized in that The method comprises the following steps: (1) Preparation of the luminescent layer by electrospinning: The electroluminescent material, solvent, and polymer as a binder are mixed and stirred to obtain a luminescent spinning solution. The electroluminescent material is loaded onto the surface of the conductive fiber by electrospinning to obtain a conductive fiber with a luminescent layer. The electroluminescent material is selected from one or more of the group consisting of zinc sulfide-doped luminescent powders ZnS:Mn, ZnS:Cl, ZnS:Cu, ZnS:Sm, ZnS:Tm, ZnS:Cu,Cl and ZnS:Mn,Cu,Cl, and the mass ratio of the electroluminescent material to the polymer is (1-5):1; (2) Preparation of color conversion layer by dyeing: The conductive fiber with the luminescent layer is dipped into the fluorescent dye solution to dye the fiber surface, and the color conversion layer is formed after drying; (3) Dip coating to prepare the dielectric layer: Dip the conductive fiber dyed with fluorescent dye into the PDMS diluent, then slowly pull it out at a uniform speed, and dry it to obtain a uniformly loaded dielectric layer; The PDMS diluent is prepared by mixing PDMS and n-hexane in a mass ratio of 1: (1-5); (4) constructing an external electrode: loading the external electrode onto the surface of the dielectric layer by winding or coating to obtain an electroluminescent fiber; the external electrode comprises a metal wire or metal particles, the metal wire comprises a silver wire, a copper wire, a silver-plated copper wire, a steel wire, a titanium wire or a tungsten wire, and the metal particles comprise a conductive silver paste, a silver nanowire, a copper nanowire or a silver nanowire; (5) Insulation packaging: A transparent insulating polymer is coated on the outside of the electroluminescent fiber, and after drying, a multi-color electroluminescent fiber with a transparent packaging layer as the outermost layer is obtained.

2. The preparation method according to claim 1, wherein: In step (1), The conductive fibers include one or more of metal conductive fibers, carbon fibers, ion gel fibers, and conductive polymer composite fibers; The particle size of the electroluminescent material is 10 to 50 μm; The solvent is a mixture of N,N-dimethylformamide and acetone in a mass ratio of (1-2):1; The polymer is selected from one of styrene-butadiene-styrene, polyurethane, and polyvinylidene fluoride-hexafluoropropylene.

3. The preparation method according to claim 1, wherein: In step (1), the steps of preparing the luminescent spinning solution are: first preparing the polymer into a polymer solution with a solid content of 10% to 20%, then adding the electroluminescent material, and mixing them evenly to obtain the luminescent spinning solution.

4. The preparation method according to claim 1, wherein: In step (1), the process parameters of electrospinning are: flow rate 0.3~1.5 mL / hr, rotation speed 140~260 rpm, and movement speed 0.5~2.5 mm / s.

5. The preparation method according to claim 1, wherein: In step (2), the drying conditions are: temperature 60-100°C, time 5-10 min; in step (3), the drying conditions are: temperature 80-120°C, time 15-30 min.

6. The preparation method according to claim 1, wherein: When the outer electrode is prepared by the winding method, the pitch is 0.2~0.8 mm; When the coating method is used to load the external electrode, the surface of the dielectric layer needs to be plasma treated to improve the hydrophilicity. The plasma treatment power is 100~150W, the treatment time is 1~5 min, and then the conductive solution is dipped in it. The dipping time is 5~30 s and the number of dipping times is 2~5. After dipping, it is dried in an oven at a temperature of 60~150 ℃.

7. The preparation method according to claim 1, wherein: In step (5), the insulating polymer is one or more of epoxy resin, acrylate resin, polyurethane resin, polytetrafluoroethylene resin, polyvinylidene fluoride resin or silicone resin; the drying conditions are: temperature 80~150℃, time 20~40 min.

8. A multicolor electroluminescent fiber produced by the method of claim 1, characterized in that: The multicolor electroluminescent fiber includes conductive fibers, a luminescent layer, a color conversion layer, a dielectric layer and an encapsulation layer from the inside to the outside. The outer surface of the dielectric layer is wound or coated with an external electrode, which is a metal wire or metal particle.

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