Multi-color planar electroluminescent device with refined patterns and preparation method of multi-color planar electroluminescent device

Abstract

The invention relates to a refined pattern multi-color planar electroluminescent device and a preparation method thereof, and belongs to the technical field of light-emitting display. According to the invention, bottom electrodes with different refined patterns are prepared through laser cutting, electroluminescent materials, namely copper zinc sulfide and PDMS, are added into a spinning solution, and a nanofiber luminescent functional layer is constructed on the different refined group bottom electrodes through electrostatic spinning. A fluorescent dye is added into a gel electrolyte precursor solution, and gel electrolyte is constructed to serve as a top electrode of the device to construct the multi-color refined electroluminescent device with a planar structure. According to the invention, multi-color and fine patterning of the planar electroluminescent device are realized, and a brand new idea is provided for application of planar electroluminescence.

Description

Technical Field

[0001] The present invention relates to a fine-pattern multi-color planar electroluminescent device and a preparation method thereof, belonging to the technical field of light-emitting displays. Background Art

[0002] With the rise of wearable devices and mobile medical technologies, the demand for new sensors and monitoring technologies that are miniaturized, low-power, highly sensitive, and capable of non-invasive or minimally invasive monitoring is becoming increasingly urgent. In this context, flexible alternating current electroluminescent (ACEL) devices have gradually become a research hotspot in the field of medical monitoring due to their small size, light weight, easy integration, etc., and can be conveniently integrated into various wearable devices or implantable devices to achieve long-term and real-time monitoring of human physiological parameters. Their potential applications in the field of medical monitoring are expected to change the traditional medical monitoring mode, improve the efficiency and quality of medical services, and bring a more convenient and accurate medical experience to patients.

[0003] Among many electroluminescent devices, planar ACEL devices have unique advantages. Due to the planar characteristics of their two-dimensional structure, the light-emitting region can receive a uniform and stable electric field intensity for excitation, effectively avoiding the situation of uneven device brightness, making the light-emitting plane show a highly consistent brightness, providing a basis for large-area display and other scenarios. However, current planar electroluminescent devices still face three key technical problems:

[0004] First of all, the electric field uniformity of the electroluminescent device is affected by the thickness uniformity of the bottom electrode, top electrode, intermediate dielectric layer, light-emitting layer, etc. How to quickly and uniformly construct the light-emitting layer is a key issue for planar electroluminescent devices. The nanofiber membrane constructed by the electrospinning process has unique advantages. Its micron-scale nanofiber structure brings a high specific surface area characteristic to the light-emitting layer, greatly increasing the effective contact area between the light-emitting material and the electrode. At the same time, the nanofiber network structure helps electrons and holes migrate and recombine more smoothly in the light-emitting layer, reducing the energy loss during the charge transport process, thereby improving the overall device's light-emitting brightness and quantum efficiency.

[0005] Secondly, due to the limitations of copper zinc sulfide materials, traditional electroluminescent devices can only emit blue-green light. How to prepare an electroluminescent device with full-color coverage is crucial. According to previous research, fluorescent dyes can absorb the light emitted by copper zinc sulfide and emit light of different colors, and the high water solubility of fluorescent dyes enables them to easily dissolve in the gel electrolyte precursor solution. Therefore, if the fluorescent dye is dissolved in the gel electrolyte precursor solution and a gel electrolyte is constructed as its top electrode, it is possible to achieve multi-color display of the device.

[0006] Finally, there is also a problem that it is difficult to fabricate fine patterns in electroluminescent devices. Since the light-emitting layer only emits light in the part where the electric field passes through, the fabrication of fine devices can be controlled by preparing a fine-patterned bottom electrode. Laser cutting can cut materials with extremely high precision, and the cut edges are neat and smooth, almost without subsequent processing, greatly improving production efficiency and product quality, and fine patterns can be constructed according to requirements.

[0007] Therefore, how to simultaneously solve the three key problems of uniform construction of the light-emitting layer, multi-color realization, and fine pattern fabrication is of great significance for developing planar electroluminescent devices with excellent performance. Summary of the Invention

[0008] Based on the above background, the object of the present invention is to provide a method for fabricating a fine-patterned multi-color planar electroluminescent device, which solves the three technical problems of uniform construction of the light-emitting layer, multi-color realization, and fine pattern fabrication described in the background art. The method of the present invention has the advantages of simple process, low cost, and the ability to customize different fine patterns and various colors as needed.

[0009] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0010] A method for fabricating a fine-patterned multi-color planar electroluminescent device, the method comprising the following steps: S1, construction of a fine bottom electrode: Select a bottom electrode material, regulate the pattern size and intensity through a laser engraving machine and perform engraving to obtain a fine bottom electrode;

[0011] S2, preparation of a spinning solution for the light-emitting layer: Dissolve thermoplastic polyurethane in a solvent, add copper zinc sulfide powder, stir until uniform, then add polydimethylsiloxane (PDMS), and continue stirring to obtain a spinning solution for the light-emitting layer;

[0012] S3, construction of a light-emitting functional layer: Using the fine bottom electrode in S1 as a substrate, perform electrospinning on the surface of the bottom electrode with the spinning solution in S2 to prepare a light-emitting functional layer;

[0013] S4, preparation of a gel electrolyte precursor solution: Add acrylamide and zinc sulfate heptahydrate to deionized water and stir, add N-N methylene bisacrylamide, and add fluorescent dyes as needed, mix evenly to obtain a gel electrolyte precursor solution; Add a thermal initiator to deionized water and stir to obtain a thermal initiator solution;

[0014] S5, preparation of a multi-color gel electrolyte: Pour the gel electrolyte precursor solution in S4 into a mold, drop the thermal initiator solution in S4, stir and then let it stand for gel initiation to obtain a multi-color gel electrolyte;

[0015] S6, construction of a fine-patterned multi-color planar electroluminescent device: the multi-color gel electrolyte obtained in S5 is bonded to the light-emitting functional layer prepared in S3 to construct a fine-patterned multi-color planar electroluminescent device.

[0016] The preparation steps of the present invention are simple. The nanofiber layer prepared by one-step electrospinning not only has the function of a light-emitting functional layer, but also acts as a dielectric layer for insulation protection to prevent device breakdown and damage, greatly simplifying the device preparation process. The fine bottom electrode prepared by laser engraving technology can realize the precise display of complex patterns, and the gel electrolyte top electrode with added fluorescent dyes realizes the multi-color display function. The innovative combination of the three technologies gives the present invention a unique advantage in the field of electroluminescent devices.

[0017] Preferably, the bottom electrode in step S1 is one or more of zinc sheet, copper sheet, aluminum foil, and liquid metal, the strength of the laser engraving machine is 10-100%, and the engraving area is 5cm×5cm-30cm×30cm. This preferred solution provides a variety of bottom electrode material options to meet the needs of different application scenarios; the setting of the laser engraving parameter range ensures the accuracy and edge smoothness of the pattern cutting, and is suitable for application requirements of different sizes.

[0018] Preferably, the molecular weight of the thermoplastic polyurethane in step S2 is 10000-50000; the spinning solution of the luminescent layer contains the following components in mass percentage of 100%: 15-25% thermoplastic polyurethane, 5-20% zinc copper sulfide, 15-25% PDMS, and the remainder is solvent, wherein the solvent is a mixture of NN dimethylformamide and tetrahydrofuran, and the mass ratio of NN dimethylformamide to tetrahydrofuran is 100:0-50:50. In this preferred embodiment, thermoplastic polyurethane as the matrix material of the nanofiber provides good mechanical strength, zinc copper sulfide as the luminescent material, PDMS has hydrophobic properties, can ensure the insulation between the two electrodes to prevent the device from short-circuiting, and the optimization of the ratio of the three ensures the performance balance of the nanofiber luminescent layer; the adjustment of the solvent ratio helps to control the viscosity and rheological properties of the spinning solution and optimize the electrospinning process.

[0019] Preferably, the electrospinning parameters in step S3 are: the distance between the needle tip and the collector is 8 cm, the syringe pump pushes the spinning solution at a speed of 1.5 mL / h, the electrostatic high voltage is 10-20 kV during the spinning process, and the collector speed is 50-150 rpm; the thickness of the obtained light-emitting layer functional layer is 0.1 mm-0.5 mm. These optimized electrospinning parameters ensure that the nanofibers are uniformly deposited on the surface of the bottom electrode, and controlling the appropriate range of the light-emitting layer thickness ensures that the insulation performance is not excessively affected while the light-emitting brightness is not affected.

[0020] Preferably, the gel electrolyte precursor solution in step S4 contains the following components based on 100% by mass: 10-20% acrylamide, 45-55% zinc sulfate heptahydrate, 0.05-0.5% N-N methylene bisacrylamide, and the balance is water; the fluorescent dye is one or more of cationic fluorescent red X-10GN and cationic fluorescent yellow X-10GFF; based on 100% of the total mass of the gel electrolyte precursor solution, the mass content of the fluorescent dye is 0.01-0.1%. In this formulation, acrylamide serves as the gel framework, high-concentration zinc sulfate heptahydrate provides sufficient ionic conductivity, N-N methylene bisacrylamide serves as a cross-linking agent to increase the gel strength, and the fluorescent dye imparts multi-color characteristics to the electroluminescent device by absorbing the light emitted by copper zinc sulfide and emitting different colored lights again.

[0021] Preferably, the thermal initiator in step S4 is one or more of potassium persulfate and ammonium persulfate; the mass percentage content of the thermal initiator in the thermal initiator solution is 5-10%, and the rest is deionized water. Selecting a thermal initiator with a small molecular structure can rapidly initiate the polymerization of acrylamide at room temperature to form a gel electrolyte, which has the advantages of low energy consumption and high efficiency.

[0022] Preferably, the weight ratio of the gel electrolyte precursor solution to the thermal initiator solution in step S5 is 25:1-25:2; the mold size is 1 cm 2 -30 cm 2 . This ratio range of the precursor to the initiator ensures the speed and integrity of gel formation, while the mold size range meets the various application requirements from small to large electroluminescent devices.

[0023] Preferably, the formulation of the light-emitting layer spinning solution in step S2 is: 5 g of thermoplastic polyurethane (TPU), 5 g of copper zinc sulfide, 5 g of PDMS, solvents: 7.5 g of N,N-dimethylformamide and 7.5 g of tetrahydrofuran; the electrostatic high voltage in the electrospinning in step S3 is 15 kV; the thickness of the obtained light-emitting layer functional layer is 0.2 mm - 0.3 mm; the formulation of the gel electrolyte precursor solution in step S4 is: 3 g of acrylamide, 5.6 g of zinc sulfate heptahydrate, 20 mg of N-N methylene bisacrylamide, and 7.5 g of deionized water. This preferred solution provides an experimentally verified optimal formulation and parameter combination. The high voltage of 15 kV can ensure the maximization of the middle thickness stability of the nanofibers, and the thickness range of 0.2 - 0.3 mm achieves the best balance between device stability and light-emitting brightness.

[0024] Preferably, based on 100% of the total mass of the gel electrolyte precursor solution, the mass content of the fluorescent dye is 0.05%. According to the experimental data, 0.05% is the optimal concentration of the fluorescent dye. This concentration can ensure the uniform distribution of color and will not significantly reduce the light-emitting brightness due to excessive dye.

[0025] A refined pattern multi-color planar electroluminescent device prepared by the above preparation method. The device adopts a planar structure design, combines a fine pattern bottom electrode, a nanofiber light-emitting layer and a gel electrolyte top electrode containing a fluorescent dye, and has the advantages of simple preparation, fine pattern, rich colors, uniform light emission, etc.

[0026] Compared with the prior art, the present invention has the following technical features and advantages:

[0027] 1. The laser engraving technology used in the present invention can quickly prepare ultra-refined patterns according to requirements, with neat and smooth cutting edges and high precision, realizing the fine pattern display of electroluminescent devices;

[0028] 2. The present invention adds an electroluminescent material to the spinning solution and uses electrospinning to prepare a nanofiber light-emitting functional layer on the surface of the bottom electrode. This structure provides a high specific surface area, increases the effective contact area between the light-emitting material and the electrode, and improves the electroluminescent efficiency;

[0029] 3. The present invention uses a small molecule structure thermal initiator to initiate the gel electrolyte, further ensuring that the nanofiber layer is not short-circuited due to wetting, ensuring the stability of the device. At the same time, adding a sufficient concentration of zinc sulfate to the acrylamide solution can be initiated at room temperature on the premise of using a thermal initiator, with the advantages of rapidity and low energy consumption;

[0030] 4. By adding a fluorescent dye to the gel electrolyte precursor solution, the present invention not only changes the color of the device under natural light conditions, but also changes the color light under electroluminescent conditions, breaking through the limitation of the single color of traditional electroluminescent devices and realizing the multi-color display of electroluminescence;

[0031] 5. The present invention separates and initiates the gel electrolyte on the surface. When needed, the gel electrolyte and the bottom electrode-nanofiber layer can be separated, enabling the repeated use of the bottom electrode-light-emitting functional layer, improving the use efficiency and economy of the device. Description of the Drawings

[0032] Figure 1 To supplement the rotational rheology curve in Example 1;

[0033] Figure 2 The FTIR curve of Supplementary Example 2;

[0034] Figure 3 The XRD curve of Supplementary Example 2;

[0035] Figure 4 The physical diagram of the electroluminescent device in Example 2 being driven by a driver;

[0036] Figure 5 To supplement the SEM image of the interface between the nanofiber layer and the gel electrolyte in Example 3;

[0037] Figure 6 To supplement the actual picture of the device lit up prepared with the nanofiber layer of uneven thickness in Example 4;

[0038] Figure 7 For the gel electrolyte precursor solutions containing different concentrations of cationic red X-10GN in Example 5, from left to right are 0.005%, 0.01%, 0.05%, 0.1%, 0.15%;

[0039] Figure 8 For the device lit up pictures of the gel electrolytes containing different concentrations of cationic red X-10GN in Example 5, from left to right are 0.005%, 0.01%, 0.05%, 0.1%, 0.15%;

[0040] Figure 9 For the electroluminescent devices with different gel electrolytes in Example 4, the left picture is the actual picture under natural light conditions, and the right picture is the actual picture after the device is lit up;

[0041] Figure 10 For the actual picture of the interdigital structure electroluminescence in Example 5, the left picture is the actual picture connecting two bottom electrodes, the middle picture is the actual picture connecting the left half and the gel electrolyte, and the right picture is the actual picture connecting the right half and the gel electrolyte;

[0042] Figure 11 For the refined pattern in Example 6, the left is the pattern input into the engraving machine, and the right is the engraved pattern;

[0043] Figure 12 For the actual picture of the refined electroluminescent device lit up in Example 6. Detailed implementation manners

[0044] The technical solutions of the present invention will be further specifically described below through specific examples. It should be understood that the implementation of the present invention is not limited to the following examples, and any formal modification and / or change made to the present invention will fall within the protection scope of the present invention.

[0045] In the present invention, unless otherwise specified, all parts and percentages are in weight units, and the equipment and raw materials used can be purchased from the market or are commonly used in the art. The methods in the following examples are all conventional methods in the art unless otherwise specified.

[0046] The reagents used in the following examples can be purchased from conventional biochemical reagent stores unless otherwise specified.

[0047] Preparation method of the nanofiber functional layer in Example 1

[0048] 1. Preparation of nanofiber spinning solution

[0049] Weigh 5 g of thermoplastic polyurethane and 5 g of copper zinc sulfide powder and dissolve them in 7.5 g of N-N dimethylformamide and 7.5 g of tetrahydrofuran solvent. Stir magnetically at room temperature for 12 h, then weigh 5 g of PDMS and add it to the solution, and stir again for 10 min to form a uniform spinning solution;

[0050] 2. Preparation of nanofiber light-emitting functional layer

[0051] Using aluminum foil as the substrate, and the spinning solution prepared in step (1), perform electrospinning with an electrospinning device. The distance between the needle tip and the collector is 8 cm, the injection pump advances the spinning solution at a speed of 1.5 mL / h, apply an electrostatic high voltage of 15 kV during the electrospinning process, and collect at a collector rotation speed of 100 rpm to prepare a nanofiber light-emitting functional layer.

[0052] Supplementary Example 1 Cross-linking analysis of spinning solution

[0053] We carried out rotational rheological tests on the spinning solution, as shown in the appendix Figure 1 As shown, it can be seen that the viscosity of the spinning solution increased significantly after adding PDMS. This is because PDMS will graft with the isocyanate at the end of TPU to carry out a certain degree of cross-linking, which can effectively improve the mechanical properties of the nanofiber layer

[0054] Supplementary Example 2 Morphology analysis of nanofiber functional layer

[0055] Infrared analysis: As shown in the appendix Figure 2 As shown, 795 cm -1 is the stretching vibration peak of Si-CH3, and 1018 cm -1 is the stretching vibration peak of Si-O-Si, which further illustrates the uniform distribution of PDMS and that the structure is not damaged by electrospinning;

[0056] XRD analysis: As shown in the appendix Figure 3 As shown, the XRD curves of zinc sulfide particles and the nanofiber light-emitting layer are as shown in the figure. It can be seen that both of them can correspond to the characteristic peaks of the #36-145 and #05-0566 PDF cards, which also indicates the uniform distribution of copper zinc sulfide in the nanofibers.

[0057] Example 2 Preparation of planar electroluminescent device

[0058] (1) Preparation of nanofiber spinning solution

[0059] As in Example 1;

[0060] (2) Preparation of nanofiber light-emitting functional layer

[0061] Using a zinc sheet as the substrate, the spinning solution prepared in step (1) is used for electrospinning with an electrospinning device. The distance between the needle tip and the collector is 8 cm, the injection pump advances the spinning solution at a speed of 1.5 mL / h, an electrostatic high voltage of 15 kV is applied during the electrospinning process, and the collector rotates at a speed of 100 rpm for collection to prepare the nanofiber light-emitting functional layer.

[0062] (3) Preparation of the gel electrolyte precursor solution

[0063] 3 g of acrylamide and 5.6 g of zinc sulfate heptahydrate are successively added to 7.5 g of deionized water, placed on a stirrer and stirred at room temperature for 5 min, and then 20 mg of N,N-methylenebisacrylamide is added and stirred on the stirrer for 5 min to obtain the gel electrolyte precursor solution; 0.5 g of potassium persulfate is added to 10 g of deionized water, placed on a stirrer and stirred at room temperature for 10 min to obtain the thermal initiator solution.

[0064] (4) Gel electrolyte construction

[0065] Using a 5 cm × 5 cm polytetrafluoroethylene (PTFE) template, 10 g of the gel electrolyte precursor solution from step (3) is poured into the mold, 0.5 g of the thermal initiator solution from step (3) is added dropwise, and the solution is quickly stirred. After standing for 2 minutes, the gel electrolyte is taken out.

[0066] (5) Preparation of the planar electroluminescent device

[0067] The gel electrolyte in step (4) is attached to the surface of the bottom electrode-nanofiber light-emitting functional layer in step (2) to obtain the preparation of the planar electroluminescent device. The physical diagram of the electroluminescent device lit by the driver is as shown in the appendix Figure 4 as follows.

[0068] Supplementary Example 3 Analysis of the nanofiber layer-gel electrolyte interface

[0069] The SEM images of the interface between the nanofiber layer and the gel electrolyte are as shown in the appendix Figure 5 as follows. It can be seen that due to the time-separated initiation, the interface is obvious. However, due to the good mechanical properties of the gel electrolyte, it can ensure good contact with the nanofiber layer to ensure uniform subsequent light emission.

[0070] Supplementary Example 4 Analysis of the nanofiber layer thickness

[0071] Due to the limitations of the electrospinning machine, the nanofiber layer in the middle part will be thicker, while the two sides are thinner. This will result in a higher impedance in the middle part and a smaller impedance on both sides, and ultimately lead to uneven brightness of the electroluminescence, as shown in the appendix Figure 6As shown, considering this limitation, we maximize the width ensuring the stability of the middle thickness by increasing the voltage to 15 kV, while limiting the thickness of the nanofiber layer to 0.2 mm - 0.3 mm. If it is too thin, the device will be unstable and short-circuit, while if it is too thick, the brightness will decrease.

[0072] Example 3 Preparation of Multicolor Planar Electroluminescent Device

[0073] (1) Preparation of nanofiber spinning solution

[0074] As in Example 1;

[0075] (2) Preparation of nanofiber light-emitting functional layer

[0076] As in Example 2;

[0077] (3) Preparation of gel electrolyte precursor solution

[0078] Add 3 g of acrylamide and 5.6 g of zinc sulfate heptahydrate to 7.5 g of deionized water in sequence, place it on a stirrer and stir at room temperature for 5 min, add 20 mg of N,N'-methylenebisacrylamide, then add different masses of cationic fluorescent red X-10GN, and place it on a stirrer and stir for 5 min to obtain a multicolor gel electrolyte precursor solution; add 0.5 g of potassium persulfate to 10 g of deionized water, place it on a stirrer and stir at room temperature for 10 min to obtain a thermal initiator solution;

[0079] (4) Construction of gel electrolyte

[0080] Use a 1.2 cm × 1.2 cm polytetrafluoroethylene (PTFE) template, take 0.2 g of the gel electrolyte precursor solution in (3) and pour it into the mold, and add 0.01 g of the thermal initiator solution in (3), and quickly stir the solution. After standing for 2 minutes, take out the gel electrolyte;

[0081] (5) Preparation of planar electroluminescent device

[0082] Attach the gel electrolyte in (4) to the surface of the bottom electrode - nanofiber light-emitting functional layer in (2) to obtain a planar electroluminescent device.

[0083] Supplementary Example 5 Influence of Fluorescent Dye on Electroluminescent Color

[0084] As shown in the appendix Figure 7 As shown, based on the total mass of the gel electrolyte precursor solution being 100%, gel electrolyte precursor solutions containing 0.005%, 0.01%, 0.05%, 0.1%, and 0.15% of cationic fluorescent red X-10GN were prepared. Planar electroluminescent devices were constructed by the method of Example 3 and lit by a driver, as shown in the appendix Figure 8As can be seen, the gel electrolytes with concentrations of 0.005% and 0.01% have uneven colors and also exhibit some blue light. However, when the concentration is greater than 0.05%, the device shows a relatively uniform purple color. As the concentration of the fluorescent dye increases, the brightness of the device gradually decreases. This is because the fluorescent dye absorbs the light of electroluminescence. Therefore, if the amount of the fluorescent dye is too large, the brightness of the electroluminescent device will suddenly decrease, and if it is too small, the color light of electroluminescence will not be completely captured by the fluorescent dye, resulting in uneven colors. Therefore, 0.05% is considered the optimal concentration.

[0085] Example 4 Preparation of Multicolor Planar Electroluminescent Device

[0086] (1) Preparation of nanofiber spinning solution

[0087] As in Example 1;

[0088] (2) Preparation of nanofiber light-emitting functional layer

[0089] As in Example 2;

[0090] (3) Preparation of gel electrolyte precursor solution

[0091] 3 g of acrylamide and 5.6 g of zinc sulfate heptahydrate were successively added to 7.5 g of deionized water, placed on a stirrer and stirred at room temperature for 5 min. Then 20 mg of N,N-methylenebisacrylamide was added, and 0.05% of cationic fluorescent red X-10GN and cationic fluorescent yellow X-10GFF were respectively added, and then placed on a stirrer and stirred for 5 min to obtain a multicolor gel electrolyte precursor solution; 0.5 g of potassium persulfate was added to 10 g of deionized water, placed on a stirrer and stirred at room temperature for 10 min to obtain a thermal initiator solution;

[0092] (4) Gel electrolyte construction

[0093] As in Example 3;

[0094] (5) Preparation of planar electroluminescent device

[0095] The gel electrolyte in (4) was pasted on the surface of the bottom electrode-nanofiber light-emitting functional layer in (2) to obtain a planar electroluminescent device. The physical diagram is as shown in the appendix Figure 9 As shown, it can be seen that the device using fluorescent yellow emits green light, and the device using fluorescent red emits purple light. As long as the doping of fluorescent yellow and fluorescent red is adjusted, different color electroluminescent device requirements can be theoretically achieved.

[0096] Example 5 Preparation of Interdigitated Structure Planar Electroluminescent Device

[0097] (1) Preparation of interdigitated structure bottom electrode

[0098] Brush the bottom electrode on the surface of the TPU hot-pressed cloth using liquid metal;

[0099] (2) Preparation of nanofiber spinning solution

[0100] As in Example 1;

[0101] (3) Preparation of nanofiber light-emitting functional layer

[0102] As in Example 2;

[0103] (4) Preparation of gel electrolyte precursor solution

[0104] As in Example 3;

[0105] (5) Gel electrolyte construction

[0106] As in Example 3;

[0107] (6) Preparation of planar electroluminescent device

[0108] Attach the gel electrolyte in (4) to the surface of the bottom electrode-nanofiber light-emitting functional layer in (2) to obtain a planar electroluminescent device. Light up the device through a driver as shown in the appendix. Figure 10 When the two electrode points are two bottom electrodes, the gel electrolyte serves as a bridging part, enabling the two patterns to emit light simultaneously. When only one bottom electrode is connected, the pattern can also emit light alone, which can make the patterns of the electroluminescent device more colorful. If designed properly, a device can produce three patterns with different meanings.

[0109] Preparation method of refined bottom electrode in Example 6

[0110] (1) Preparation of refined structure bottom electrode

[0111] Cut a zinc sheet with a size of 10 cm × 10 cm. Draw the required refined pattern in advance through PS software and transfer it to a laser engraving machine for laser engraving. The intensity of the laser engraving machine is 80%. The input refined pattern and the engraved pattern are as shown in the appendix. Figure 11 As shown.

[0112] (2) Preparation of nanofiber spinning solution

[0113] As in Example 1;

[0114] (3) Preparation of nanofiber light-emitting functional layer

[0115] As in Example 2;

[0116] (4) Preparation of gel electrolyte precursor solution

[0117] As in Example 3;

[0118] (5) Gel electrolyte construction

[0119] Such as Example 3;

[0120] (6) Preparation of planar electroluminescent device

[0121] Attach the gel electrolyte in (4) to the surface of the bottom electrode-nanofiber light-emitting functional layer in (2) to obtain a planar electroluminescent device. Light up the device through a driver as shown in the appendix Figure 12 It can be seen that due to the refinement of the bottom electrode, the refinement of the final device is achieved, which provides a new idea for the preparation of refined planar electroluminescent devices.

[0122] In summary, the nanofiber light-emitting functional layer described in the present invention has the dual functions of a light-emitting layer and a dielectric layer, and can prevent the device from being broken down and damaged. A clear interface is formed at the contact interface between the gel electrolyte and the light-emitting functional layer. The gel electrolyte can be separated from the bottom electrode-light-emitting functional layer, enabling the bottom electrode-light-emitting functional layer to be reused. The fluorescent dye can absorb the blue-green light emitted by copper zinc sulfide and re-emit light of different colors, thereby realizing multi-color display of the electroluminescent device.

[0123] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts between each embodiment can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the method part.

Claims

1. A method for preparing a fine pattern multi-color planar electroluminescent device, characterized in that: The method comprises the following steps: S1, fine bottom electrode construction: select the bottom electrode material, adjust the pattern size and strength through a laser engraving machine and perform engraving to obtain a fine bottom electrode; S2, preparation of the luminescent layer spinning solution: dissolving thermoplastic polyurethane in a solvent, adding zinc copper sulfide powder, stirring until uniform, then adding polydimethylsiloxane (PDMS), and continuing to stir to obtain the luminescent layer spinning solution; S3, light-emitting functional layer construction: using the refined bottom electrode in S1 as a substrate, electrospinning is performed on the surface of the bottom electrode using the spinning solution in S2 to prepare a light-emitting functional layer; S4, preparation of gel electrolyte precursor solution: adding acrylamide and zinc sulfate heptahydrate into deionized water and stirring, adding NN methylenebisacrylamide, adding fluorescent dye as needed, and mixing well to obtain a gel electrolyte precursor solution; adding a thermal initiator into deionized water and stirring to obtain a thermal initiator solution; S5, preparation of multi-color gel electrolyte: pouring the gel electrolyte precursor solution in S4 into a mold, and dripping the thermal initiator solution in S4, stirring and then standing to wait for gel initiation, to obtain a multi-color gel electrolyte; S6, construction of a fine-patterned multi-color planar electroluminescent device: the multi-color gel electrolyte obtained in S5 is bonded to the light-emitting functional layer prepared in S3 to construct a fine-patterned multi-color planar electroluminescent device.

2. The preparation method according to claim 1, characterized in that: The bottom electrode described in step S1 is one or more of zinc sheet, copper sheet, aluminum foil, and liquid metal. The intensity of the laser engraving machine is 10-100%, and the engraving area is 5 cm×5 cm-30 cm×30 cm.

3. The preparation method according to claim 1, characterized in that: The molecular weight of the thermoplastic polyurethane in step S2 is 10000-50000; the light-emitting layer spinning solution contains the following components in 100% by mass: 15-25% thermoplastic polyurethane, 5-20% zinc copper sulfide, 15-25% PDMS, and the remainder is solvent, wherein the solvent is a mixture of NN dimethylformamide and tetrahydrofuran, and the mass ratio of NN dimethylformamide to tetrahydrofuran is 100:0-50:

50.

4. The preparation method according to claim 1, characterized in that: The electrospinning parameters in step S3 are: the distance between the needle tip and the collector is 8 cm, the syringe pump pushes the spinning solution at a rate of 1.5 mL / h, the electrostatic high voltage is 10-20 kV during the spinning process, and the collector speed is 50-150 rpm; The thickness of the obtained light-emitting layer functional layer is 0.1 mm-0.5 mm.

5. The preparation method according to claim 1, characterized in that: In step S4, the gel electrolyte precursor solution contains the following components in mass percentage as 100%: 10-20% acrylamide, 45-55% zinc sulfate heptahydrate, 0.05-0.5% NN methylenebisacrylamide, and the balance is water; the fluorescent dye is one or more of cationic fluorescent red X-10GN and cationic fluorescent yellow X-10GFF; based on the total mass of the gel electrolyte precursor solution as 100%, the mass content of the fluorescent dye is 0.01-0.1%.

6. The preparation method according to claim 1, characterized in that: In step S4, the thermal initiator is one or more of potassium persulfate and ammonium persulfate; the mass percentage of the thermal initiator in the thermal initiator solution is 5-10%, and the rest is deionized water.

7. The preparation method according to claim 1, characterized in that: In step S5, the weight ratio of the gel electrolyte precursor solution to the thermal initiator solution is 25:1-25:2; and the mold size is 1 cm²-30 cm².

8. The preparation method according to claim 1, characterized in that: The formula of the spinning solution of the light-emitting layer in step S2 is: 5 g of thermoplastic polyurethane (TPU), 5 g of zinc copper sulfide, 5 g of PDMS, and solvent: 7.5 g of NN dimethylformamide and 7.5 g of tetrahydrofuran; The electrostatic high voltage of the electrospinning in step S3 is 15 kV; the thickness of the obtained light-emitting layer functional layer is 0.2 mm-0.3 mm; The formula of the gel electrolyte precursor solution in step S4 is: 3 g acrylamide, 5.6 g zinc sulfate heptahydrate, 20 mg NN methylenebisacrylamide, and 7.5 g deionized water.

9. The preparation method according to claim 1, characterized in that: Based on the total mass of the gel electrolyte precursor solution being 100%, the mass content of the fluorescent dye is 0.05%.

10. A fine pattern multi-color planar electroluminescent device manufactured by the manufacturing method of claim 1.

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