High color purity multicolor electroluminescent fiber and its preparation method and application

Abstract

The application belongs to the technical field of intelligent electronic devices, and particularly relates to a high-color-purity multi-color electroluminescent fiber and a preparation method and application thereof. The fiber is prepared by the following steps: preparing lead halide perovskite type nano quantum dots as light conversion particles by a hot injection method, a room temperature supersaturation recrystallization method and the like; grafting and modifying the lead halide perovskite type nano quantum dots on the surface of metal sulfide type electroluminescent particles through a surface ligand to obtain high-color-purity multi-color electroluminescent active material; compounding the light conversion particle modified electroluminescent active material and a transparent thermoplastic elastomer polymer to obtain active slurry, and coating the active slurry on the surface of a conductive fiber through a continuous limited coating process; loading an external electrode on the conductive fiber to obtain the high-color-purity multi-color electroluminescent fiber. The multi-color electroluminescent fiber prepared by the application has various colors and high color purity, and meets the color gamut range required by the luminescent fiber and display fabric.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of intelligent electronic devices, and particularly relates to a high-color-purity multi-color electroluminescent fiber as well as a preparation method and application thereof. BACKGROUND

[0002] In recent years, with the cross and integration development of material science, information technology and medical field, people have put forward more and more demands for electronic devices, such as flexibility, wearability, self-healing and the like. Vision is the main way for human beings to obtain information from the outside world, and traditional display devices have been difficult to meet the development requirements of flexible display devices in terms of flexibility, lightness and portability. Considering that various complex deformations such as twisting, bending and stretching need to be faced in the application process, the fabric light-emitting display device shows unique advantages and can be obtained by weaving electroluminescent fibers. Through circuit design, pattern display, information interaction and the like can be realized, so as to be widely concerned by the scientific community and the industry as a new type of flexible intelligent electronic device. Among them, the performance of the light-emitting fiber is the key factor to determine the performance of the display fabric, including pixel density, color type, brightness and purity and the like.

[0003] However, the electroluminescent fiber currently faces the challenges of single display color and poor color purity. In the patent CN202310048457.9, new light-emitting colors are compounded by adding micron-sized fluorescent pigment particles in the light-emitting paste. However, as a down-conversion material, the fluorescent powder has a wide spectrum, and the fiber light-emitting color is not pure enough. In the literature "Color-tunable light-emitting fibers for pattern displaying textiles" J. Mater. Chem. C, 2024, 12, 941, it is reported that the color of the light-emitting fiber can be dynamically adjusted by constructing a double light-emitting layer with zinc sulfide light-emitting powder emitting orange light and blue light respectively. However, the spectrum of the emitted light is actually the composite color of the two kinds of light, resulting in low light brightness, limited color range and poor color purity.

[0004] Quantum dot material is a kind of semiconductor nanocrystal with excellent photoelectric performance, which can absorb ultraviolet to visible light and emit other colors of visible light through down-conversion. These lights have very narrow half-width and very high color purity, which is higher than that of liquid crystal television and the color standard of the United States National Television Standards Committee. The quantum dot material can be used in the preparation of light-emitting fiber devices to obtain correct light-emitting color.

[0005] To this end, the application proposes to use lead halide perovskite quantum dot nanomaterial as light conversion material, graft traditional electroluminescent material to prepare a new type of electroluminescent material, and then obtain a high color purity multi-color electroluminescent fiber. By adjusting the types and proportions of halogens, the color gamut range of the electroluminescent fiber is widened. SUMMARY

[0006] The application aims to provide a high color purity multi-color electroluminescent fiber and its preparation method and application to realize the diversification of light-emitting colors and improve the color purity and color gamut range, based on the problem of single display color and poor color purity of the electroluminescent fiber.

[0007] The high color purity multi-color electroluminescent fiber provided by the application is to graft lead halide perovskite quantum dot nanomaterial to the surface of traditional alternating current electroluminescent particles, and to change the composition and proportion of quantum dot materials to directionally control the light-emitting color, so as to obtain a high color purity multi-color electroluminescent fiber.

[0008] The specific steps of the preparation method are as follows:

[0009] (1) Preparation of quantum dot light conversion particles: lead halide perovskite nanometer quantum dots (CsPbX3 QDs) are prepared by a hot injection method, a room temperature supersaturation recrystallization method or the like as light conversion particles;

[0010] (2) Preparation of light conversion particle modified electroluminescent active material: lead halide perovskite nanometer quantum dots are grafted and modified on the surface of metal sulfide type electroluminescent particles by surface ligands to obtain high color purity multi-color electroluminescent active material; the color of the electroluminescent active material can be directionally controlled by changing the types and proportions of halogens in the perovskite nanometer quantum dot material;

[0011] (3) Loading of light-emitting active layer: the light conversion particle modified electroluminescent active material and transparent thermoplastic elastomer polymer are compounded to obtain uniform and stable light-emitting active slurry, the light-emitting active slurry is coated on the surface of the conductive fiber by a continuous limited coating process to obtain conductive fiber coated with electroluminescent active layer;

[0012] (4) Loading of fiber external electrode: the external electrode is loaded on the conductive fiber coated with the electroluminescent active layer in the form of twisting or plying to obtain high color purity multi-color electroluminescent fiber, and the light-emitting color is pure red, orange, yellow, green, blue, purple and white.

[0013] In the application, in step (1), the types of halogens in the perovskite nanometer quantum dots are Cl, Br and I, and the size of the perovskite nanometer quantum dots is 5-20 nm.

[0014] In this invention, the specific steps of the heat injection method in step (1) are as follows:

[0015] Select 0.276-0.4g Cs2CO3, 10-15mL octadecene (ODE) and 0.833-1.76mL surface ligand, mix and stir them into a three-necked flask, heat to 120-140℃ under N2 atmosphere and dry for 0.5-1 hour to obtain cesium oleate precursor solution;

[0016] 0.376-0.752 mmol PbX2 (X = Cl, Br, I) and 10-20 mL ODE were placed in a 100 mL flask and heated to 120-140 °C under a N2 atmosphere and dried for 0.5-1 hour. Then, 1-2 mL of the surface ligand was slowly injected into the flask with stirring until the solution became clear. The flask was heated to 160-180 °C, and 0.8-1.6 mL of cesium oleate precursor solution was quickly injected. After standing for 5-10 seconds, the mixture was cooled to room temperature using an ice-water bath. The solution was washed with an antisolvent and redispersed in 1-2 mL of toluene or n-hexane for further use.

[0017] Furthermore, the surface ligand is one or a mixture of oleic acid (OA), oleylamine (OAm), 3-aminopropyltriethoxysilane (APTES), and trioctylphosphine (TOP).

[0018] Furthermore, the antisolvent is ethyl acetate or methyl acetate.

[0019] In this invention, the specific steps of the room temperature supersaturated recrystallization method in step (1) are as follows:

[0020] Dissolve 0.4–0.8 mmol PbX2 and 0.4–0.8 mmol CsX (X = Cl, Br, I) in 10 mL DMF or DMSO, add 1 mL of surface ligand to stabilize the precursor solution; then, under vigorous stirring, rapidly add 0.5–1 mL of the precursor solution to 10 mL toluene.

[0021] Furthermore, the surface ligand comprises one or more of oleic acid (OA), oleylamine (OAm), and 3-aminopropyltriethoxysilane (APTES).

[0022] In this invention, step (2) includes two grafting modification methods, specifically:

[0023] Method 1: Mix 0.5-1g of electroluminescent particles with 2mL of perovskite nanocrystal solution, add 2-5μL of deionized water, and stir at 60-80℃ for 24-30 hours; then add 5-20μL of silane coupling agent and 2-5μL of deionized water, and stir at 60-80℃ for 6-8 hours; collect the precipitate by centrifugation, wash three times with toluene; dry under vacuum to obtain the electroluminescent active material modified with nano-quantum dots;

[0024] or:

[0025] Method 2: Add 5 μL of silane coupling agent to 2 mL of perovskite nanocrystal solution, sonicate and stir for 1 hour; add 0.5-1.2 g of electroluminescent particles, 5-10 μL of silane coupling agent and 2-5 μL of deionized water, stir at 45 °C for 24-32 hours; collect the precipitate by centrifugation, wash three times with toluene; dry under vacuum to obtain the electroluminescent active material modified with nano-quantum dots;

[0026] When the hot injection method is used in step (1), the grafting modification method in step (2) shall be either method one or method two.

[0027] When the room temperature supersaturated recrystallization method is used in step (1), the grafting modification method in step (2) shall be selected as method two.

[0028] Furthermore, the electroluminescent particles are CaS, SrS, or ZnS.

[0029] Furthermore, the silane coupling agent is 3-aminopropyltriethoxysilane (APTES), γ-mercaptopropyltriethoxysilane (MPTES), or γ-mercaptopropyltrimethoxysilane (MPTMS).

[0030] In this invention, in step (2), the particle size of the obtained nano-quantum dot modified electroluminescent active material is 0.5-5 μm; the thickness of the electroluminescent active layer is 10-50 μm.

[0031] In this invention, in step (3), the conductive fiber is a metal conductive fiber, an ion gel fiber, or a conductive polymer composite fiber.

[0032] In this invention, in step (3), the transparent thermoplastic elastomer polymer is a polyester polyurethane, fluororubber, or thermoplastic polyolefin elastomer.

[0033] In this invention, in step (3), the diameter of the conductive fiber is 50-120 μm; the resistance of the conductive fiber is 5-50 Ω / m.

[0034] In this invention, in step (3), the coating thickness of the electroluminescent active layer is 10-50 μm.

[0035] In this invention, in step (3), the coating process is a conventional process, specifically: dip coating and heat curing, with a dip coating speed of 0.1-1m / min and a heating temperature of 60-100℃.

[0036] In this invention, in step (4), the external electrode is a metal wire, which is a copper wire, silver wire, stainless steel wire or aluminum wire; the diameter of the metal wire is 30-80μm and the resistance is 0.5-50Ω / m.

[0037] In this invention, in step (4), the twisting or twisting process specifically involves a pitch of 0.1-2 mm and a speed of 1-10 m / min.

[0038] In this invention, the high color purity multicolor electroluminescent fiber obtained by the above preparation method includes, from the inside out, a conductive fiber, a light-emitting active layer, and an outer electrode, forming an electrode-light-emitting layer-electrode structure, i.e., a "sandwich" structure.

[0039] The luminescent fiber has a diameter of 0.20-0.25 mm, a luminous brightness of 30-60 cd / m2, and emits pure red, orange, yellow, green, blue, purple, and white colors with high color purity.

[0040] In this invention, the high color purity multicolor electroluminescent fiber can be used as a clothing material in the production of garments by weaving, embroidery, and knitting.

[0041] Compared with the prior art, the present invention has the following advantages:

[0042] (1) A novel light-emitting-light-conversion electroluminescent material was synthesized by grafting traditional light-emitting materials with lead halide perovskite quantum dots. The emission spectrum obtained by changing the size of the quantum dots and the halogen composition has high color purity and wide color gamut.

[0043] (2) The process of this invention is simple and the conditions are mild. The luminescent fibers prepared are diverse in color and have good flexibility. They can be woven, embroidered, knitted, etc., and have important application value in the field of smart clothing. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of a high-color-purity multi-color electroluminescent fiber structure.

[0045] Figure 2 The figures show the electroluminescence spectra of blue, green, and red light-emitting fibers. In the figure, 4 represents the spectral curve of the blue light-emitting fiber, 5 represents the spectral curve of the green electroluminescent fiber, and 6 represents the spectral curve of the red electroluminescent fiber.

[0046] Figure 3This is a CIE color coordinate diagram for blue, green, and red electroluminescent fibers. In the diagram, A represents the CIE color coordinates of the blue electroluminescent fiber, B represents the CIE color coordinates of the green electroluminescent fiber, and C represents the CIE color coordinates of the red electroluminescent fiber.

[0047] In the diagram, the numbers represent: 1 for conductive fiber, 2 for electroluminescent active layer, and 3 for external electrode. Specific implementation methods

[0048] The present invention will be further described below by way of embodiments, but the invention is not limited to the scope of the embodiments described. Experimental methods in the following embodiments that do not specify specific conditions are performed according to conventional methods and conditions, or as selected according to the product instructions.

[0049] In this invention, room temperature refers to an ambient temperature of 10-30℃.

[0050] All reagents used in the following examples were purchased externally, and all solvents were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. All equipment used in the following examples was commercially available.

[0051] Example 1

[0052] Step 1: Preparation of nano-quantum dots as light conversion particles: 0.4 g Cs₂CO₃, 15 mL ODE, and 1.76 mL OA were added to a 100 mL three-necked flask with stirring, heated to 120 °C under N₂ atmosphere, and dried for 1 hour. 0.376 mmol PbBr₂ and 10 mL ODE were added to a 100 mL three-necked flask, heated to 120 °C under N₂ atmosphere, and dried for 1 hour. Subsequently, 1 mL OA and 1 mL APTES were slowly injected into a second flask with stirring until the solution became clear. The temperature was increased to 160 °C, and 0.8 mL of Cs-OA precursor solution was rapidly injected. After standing for 10 seconds, the mixture was cooled to room temperature using an ice-water bath to obtain CsPbBr₃ quantum dots (10 nm in diameter, emitting green light). The dots were washed with ethyl acetate, centrifuged at 11000 rpm for 5 min, and then redispersed in 2 mL of n-hexane.

[0053] Step 2: Preparation of novel electroluminescent active material grafted with quantum dots: 1 g CaS was mixed with 2 mL of CsPbBr3 quantum dot solution, and 2 μL of deionized water was added. The mixture was stirred at 80 °C for 24 hours. Then, 10 μL of APTES and 2 μL of deionized water were added, and the mixture was stirred at 80 °C for 6 hours. The precipitate was collected by centrifugation, washed three times with toluene, and dried under vacuum to obtain the novel electroluminescent active material CaS-g-CsPbBr3 QDs (particle size 0.5 μm, emitting green light) grafted with quantum dots.

[0054] Step 3: Loading the luminescent active layer: Take 1g of polyurethane and 4g of the novel electroluminescent active material, mix them evenly at room temperature to obtain a uniformly dispersed luminescent slurry. Apply the active luminescent slurry to the surface of a 120μm diameter copper wire fiber through a 150μm limiting hole at a coating speed of 0.1m / min, and then heat and cure at 100℃ to obtain a conductive fiber with a loaded luminescent active layer.

[0055] Step 4: Loading the external electrode: Turn on the twisting device and load the copper wire fiber (30μm in diameter) onto the fiber from Step 3 at a twisting speed of 4m / min and a pitch of 0.5mm, obtaining a high-purity green electroluminescent fiber. Its electroluminescence spectrum is as follows: Figure 2 As shown by arrow 5, the CIE color coordinates are as follows: Figure 3 As shown in circle B.

[0056] Example 2

[0057] Step 1: Preparation of nano-quantum dots as light conversion particles: 0.276 g Cs₂CO₃, 10 mL ODE, and 0.833 mL OA were added to a 100 mL three-necked flask with stirring, heated to 140 °C under N₂ atmosphere, and dried for 1 hour. 0.251 mmol PbBr₂, 0.501 mmol PbI₂, and 20 mL ODE were added to a 100 mL three-necked flask, heated to 140 °C under N₂ atmosphere, and dried for 1 hour. Subsequently, 2 mL OA and 2 mL OAm were slowly injected into a second flask with stirring until the solution became clear. The temperature was increased to 160 °C, and 2 mL of the Cs-OA precursor solution was rapidly injected. After standing for 5 seconds, the mixture was cooled to room temperature using an ice-water bath to obtain CsPbBrI₂ quantum dots (particle size 20 nm, emitting red light). The dots were washed with methyl acetate, centrifuged at 11000 rpm for 5 min, and then redispersed in 2 mL toluene.

[0058] Step 2: Preparation of novel electroluminescent active material grafted with quantum dots: Add 5 μL MPTMS to 2 mL of CsPbBrI2 quantum dot solution, sonicate and stir for 1 hour. Add 0.5 g ZnS, 10 μL MPTMS and 5 μL deionized water, stir at 45 °C for 32 hours. Collect the precipitate by centrifugation, wash three times with toluene, and dry under vacuum to obtain the novel electroluminescent active material ZnS-g-CsPbBrI2 (particle size 5 μm, emitting red light) grafted with quantum dots.

[0059] Step 3: Loading the luminescent active layer: Take 1g of polyurethane and 0.43g of the novel electroluminescent active material, mix them evenly at room temperature to obtain a uniformly dispersed luminescent slurry. Apply the active luminescent slurry to the surface of a 50μm diameter silver-plated nylon fiber through a 120μm limiting hole at a coating speed of 0.5m / min, and then heat and cure at 80℃ to obtain a conductive fiber with a loaded luminescent active layer.

[0060] Step 4: Loading the external electrode: Turn on the twisting device and load the aluminum wire fiber (50μm in diameter) onto the fiber from Step 3 at a twisting speed of 1m / min and a pitch of 0.1mm, obtaining a high-purity red electroluminescent fiber. Its electroluminescence spectrum is as follows: Figure 2 As shown by arrow 6, the CIE color coordinates are as follows: Figure 3 As shown in circle C.

[0061] Example 3

[0062] Step 1: Preparation of nano-quantum dots as light-converting particles: 0.4 g Cs₂CO₃, 15 mL ODE, and 1.76 mL OA were added to a 100 mL three-necked flask with stirring, heated to 120 °C under N₂ atmosphere, and dried for 1 hour. 0.125 mmol PbCl₂, 0.251 mmol PbBr₂, and 10 mL ODE were added to a 100 mL three-necked flask, heated to 120 °C under N₂ atmosphere, and dried for 1 hour. Subsequently, 1 mL TOP, 1 mL OA, and 1 mL OAm were slowly injected into a second flask with stirring until the solution became clear. The temperature was raised to 180 °C, and 1 mL of the Cs-OA precursor solution was rapidly injected. After standing for 5 seconds, the mixture was cooled to room temperature using an ice-water bath to obtain CsPbBr₂Cl quantum dots (15 nm in diameter, emitting blue light). Wash with methyl acetate and centrifuge at 11,000 rpm for 5 min, then redisperse in 1 mL of n-octane.

[0063] Step 2: Preparation of novel electroluminescent active material grafted with quantum dots: Add 5 μL of MPTES to 1 mL of CsPbBr2Cl quantum dot solution, sonicate and stir for 1 hour. Add 1 g SrS, 5 μL of MPTES and 2 μL of deionized water, stir at 45 °C for 32 hours. Collect the precipitate by centrifugation, wash three times with toluene. Dry under vacuum to obtain the novel electroluminescent active material SrS-g-CsPbBr2Cl (particle size 2 μm, emitting blue light) grafted with quantum dots.

[0064] Step 3: Loading the luminescent active layer: Take 1g of polyurethane and 3g of the novel electroluminescent active material, mix them evenly at room temperature to obtain a uniformly dispersed luminescent slurry. Apply the active luminescent slurry to the surface of a conductive aramid fiber with a diameter of 80μm through a 180μm limiting hole at a coating speed of 1m / min, and then heat and cure at 60℃ to obtain a conductive fiber with a loaded luminescent active layer.

[0065] Step 4: Loading the external electrode: Turn on the twisting device and load the stainless steel wire fiber (70μm in diameter) onto the fiber from Step 3 at a twisting speed of 10m / min with a pitch of 2mm, obtaining a high-purity blue electroluminescent fiber. Its electroluminescence spectrum is as follows: Figure 2 As shown by arrow 4, the CIE color coordinates are as follows: Figure 3 As shown in circle A.

[0066] Example 4

[0067] Step 1: Preparation of nano-quantum dots as light conversion particles: 0.4 mmol PbBr2 and 0.4 mmol CsBr were dissolved in 10 mL DMF. 1 mL OA and 1 mL APTES were added to stabilize the precursor solution. Then, under vigorous stirring, 1 mL of the precursor solution was rapidly added to 10 mL toluene to obtain CsPbBr3 quantum dots (8 nm in diameter, emitting green light).

[0068] Step 2: Preparation of novel electroluminescent active material grafted with quantum dots: Take 2 mL of CsPbBr3 quantum dot solution, add 5 μL of APTES, sonicate and stir for 1 hour, then add 0.5 g ZnS, 5 μL of APTES and 5 μL of deionized water, and stir at 45℃ for 24 hours. Centrifuge to collect the precipitate, wash three times with toluene, and dry under vacuum to obtain the novel electroluminescent active material ZnS-g-CsPbBr3 (particle size 3.5 μm, emitting green light) grafted with quantum dots.

[0069] Step 3: Loading the luminescent active layer: Take 1g of polyurethane and 3g of the novel electroluminescent active material, mix them evenly at room temperature to obtain a uniformly dispersed luminescent slurry. Apply the active luminescent slurry to the surface of a 100μm diameter copper wire through a 160μm limiting hole at a coating speed of 0.8m / min, and then heat and cure at 60℃ to obtain conductive fibers with a loaded luminescent active layer.

[0070] Step 4: Loading the external electrode: Turn on the twisting device and load the silver fiber (80μm in diameter) onto the fiber from Step 3 at a twisting speed of 2m / min and a pitch of 0.5mm, obtaining a high-purity green electroluminescent fiber. Its electroluminescence spectrum is as follows: Figure 2 As shown by arrow 5, the CIE color coordinates are as follows: Figure 3 As shown in circle B.

Claims

1. A method for preparing high-color-purity multi-color electroluminescent fibers, characterized in that, The specific steps are as follows: (1) Preparation of quantum dot light conversion particles: Lead halide perovskite type nano quantum dots CsPbX3 QDs were prepared by hot injection method or room temperature supersaturated recrystallization method as light conversion particles; (2) Preparation of electroluminescent active materials modified with light conversion particles: Lead halide perovskite type nano-quantum dots are grafted onto the surface of metal sulfide type electroluminescent particles through surface ligands to obtain high color purity multicolor electroluminescent active materials. The color of electroluminescent active materials can be directionally controlled by changing the type and proportion of halogen X in perovskite quantum dot materials. The perovskite quantum dots contain halogens of Cl, Br, and I, and the size of the perovskite quantum dots is 5-20 nm. (3) Loaded luminescent active layer: The electroluminescent active material modified with light conversion particles is combined with a transparent thermoplastic elastomer polymer to obtain a uniform and stable luminescent active slurry. The luminescent active slurry is coated on the surface of conductive fibers through a continuous confined coating process to obtain conductive fibers coated with an electroluminescent active layer. (4) Loading fiber external electrode: The external electrode is loaded onto the conductive fiber coated with electroluminescent active layer by twisting or twisting to obtain high color purity multicolor electroluminescent fiber with pure red, orange, yellow, green, blue, purple and white light emission colors.

2. The preparation method according to claim 1, characterized in that, In step (1): The specific steps of the heat injection method are as follows: Select 0.276-0.4 g Cs2CO3, 10-15 mL octadecene (ODE) and 0.833-1.76 mL surface ligand, mix and stir them into a three-necked flask, heat to 120-140 °C under N2 atmosphere and dry for 0.5-1 hour to obtain cesium oleate precursor solution; 0.376–0.752 mmol PbX2 and 10–20 mL octadecene were placed in a 100 mL flask (X = Cl, Br, I). The mixture was heated to 120–140 °C under a N2 atmosphere and dried for 0.5–1 hour. Subsequently, 1–2 mL of the surface ligand was slowly injected into the flask with stirring until the solution became clear. The flask was heated to 160–180 °C, and 0.8–1.6 mL of the cesium oleate precursor solution was rapidly injected. After standing for 5–10 seconds, the mixture was cooled to room temperature using an ice-water bath. The solution was washed with an antisolvent and redispersed in 1–2 mL of toluene or n-hexane for further use. The specific steps of the room temperature supersaturated recrystallization method are as follows: Dissolve 0.4–0.8 mmol PbX2 and 0.4–0.8 mmol CsX in 10 mL DMF or DMSO, where X = Cl, Br, I; add 1 mL of surface ligand to stabilize the precursor solution; then, under vigorous stirring, rapidly add 0.5–1 mL of the precursor solution to 10 mL of toluene.

3. The preparation method according to claim 2, characterized in that: In the hot injection method, the surface ligand is one or a mixture of oleic acid (OA), oleylamine (OAm), 3-aminopropyltriethoxysilane (APTES), and trioctylphosphine (TOP); the antisolvent is ethyl acetate or methyl acetate. In the room temperature supersaturated recrystallization method, the surface ligand is one or a mixture of oleic acid OA, oleylamine OAM, and 3-aminopropyltriethoxysilane APTES.

4. The preparation method according to claim 1, characterized in that: In step (2), the grafting modification method includes two types, specifically: Method 1: Mix 0.5-1 g of electroluminescent particles with 2 mL of perovskite nanocrystal solution, add 2-5 μL of deionized water, and stir at 60-80 ℃ for 24-30 hours; then add 5-20 μL of silane coupling agent and 2-5 μL of deionized water, and stir at 60-80 ℃ for 6-8 hours; collect the precipitate by centrifugation, wash three times with toluene; dry under vacuum to obtain electroluminescent active material modified with nano-quantum dots; or: Method 2: Add 5 μL of silane coupling agent to 2 mL of perovskite nanocrystal solution, sonicate and stir for 1 hour; add 0.5-1.2 g of electroluminescent particles, 5-10 μL of silane coupling agent and 2-5 μL of deionized water, stir at 45 ℃ for 24-32 hours; collect the precipitate by centrifugation, wash three times with toluene; dry under vacuum to obtain the electroluminescent active material modified with nano-quantum dots; When the hot injection method is used in step (1), the grafting modification method in step (2) shall be either method one or method two. When the room temperature supersaturated recrystallization method is used in step (1), the grafting modification method in step (2) shall be selected as method two.

5. The preparation method according to claim 4, characterized in that, The electroluminescent particles are CaS, SrS, or ZnS; The silane coupling agent is 3-aminopropyltriethoxysilane APTES, γ-mercaptopropyltriethoxysilane MPTES, or γ-mercaptopropyltrimethoxysilane MPTMS.

6. The preparation method according to claim 5, characterized in that, The obtained nano-quantum dot-modified electroluminescent active materials have a particle size of 0.5-5 μm.

7. The preparation method according to claim 1, characterized in that, In step (3): The conductive fiber is a metal conductive fiber, an ion gel fiber, or a conductive polymer composite fiber; The transparent thermoplastic elastomer polymer is a polyester-type polyurethane, fluororubber, or thermoplastic polyolefin elastomer; The conductive fiber has a diameter of 50-120 μm and a resistance of 5-50 Ω / m. The coating thickness of the electroluminescent active layer is 10-50 μm; the coating process is as follows: dip coating and heat curing, the dip coating speed is 0.1-1 m / min, and the heating temperature is 60-100 ℃.

8. The preparation method according to claim 1, characterized in that, In step (4), the external electrode is a metal wire, specifically selected from copper wire, silver wire, stainless steel wire, and aluminum wire; the diameter of the metal wire is 30-80 μm, and the resistance is 0.5-50 Ω / m; The twisting or braiding process specifically involves a pitch of 0.1-2 mm and a speed of 1-10 m / min.

9. The high color purity multicolor electroluminescent fiber obtained by the preparation method according to any one of claims 1 to 8, wherein the luminescent fiber comprises, from the inside out: The conductive fiber, the light-emitting active layer, and the external electrode form an electrode-light-emitting layer-electrode structure, i.e., a "sandwich" structure. The luminescent fiber has a diameter of 0.20-0.25 mm and a luminous intensity of 30-60 cd / m². 2 The colors of the light emitted include pure red, orange, yellow, green, blue, purple, and white.

10. The application of the high color purity multicolor electroluminescent fiber as described in claim 9 as a clothing material in the production of garments by weaving, embroidery, and knitting methods.

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