Electrochromic film and method of making the same

Abstract

The application provides an electrochromic film and a preparation method thereof, and the method comprises the following steps: providing a substrate, preparing a Eu + doping a crystalline WO3 bottom layer; preparing Mo 6+ doping an amorphous WO3 intermediate layer; performing an amino treatment on the intermediate layer, and covalently connecting viologen to Mo 6+ doping an electrode surface of the amorphous WO3 intermediate layer to obtain a covalent substrate; introducing a transition layer on the covalent substrate, and preparing an electrochemical polymerization polyaniline top layer based on the covalent substrate to obtain a device cathode; preparing a double-salt anti-freezing gel electrolyte, exposing and developing a required pattern on a surface of the electrochemical polymerization polyaniline top layer; cutting the double-salt anti-freezing gel electrolyte into gel blocks corresponding to the required pattern of the device cathode, assembling the gel blocks on the required pattern of the device cathode, covering an anode on the gel blocks, and packaging to obtain the electrochromic film. The application improves the performance of the electrochromic film.

Description

Technical Field

[0001] This invention relates to the field of electrochromic film preparation technology, and particularly to an electrochromic film and its preparation method. Background Technology

[0002] Electrochromism refers to the phenomenon where a material's optical properties (such as color, transmittance, and reflectivity) undergo stable and reversible changes under the influence of an applied electric field. Electrochromic devices based on this principle have broad application prospects in fields such as smart windows, automotive anti-glare rearview mirrors, and wearable display devices. Among these, the electrochromic film, as a core functional component, directly determines the device's response speed, optical modulation range, cycle stability, and energy consumption level.

[0003] In existing technologies, inorganic electrochromic materials, represented by tungsten trioxide (WO3), have become the mainstream choice due to their good chemical stability and long cycle life. However, monocrystalline WO3 films suffer from low ion diffusion rates and slow response speeds, while amorphous WO3 films, although exhibiting fast ion diffusion, suffer from poor cycle stability. A single material system cannot simultaneously meet the dual requirements of response speed and cycle stability. Furthermore, while liquid electrolytes possess high ionic conductivity, they suffer from drawbacks such as easy leakage, difficult encapsulation, and inconvenience in portability. Solid electrolytes, while solving the leakage problem, generally exhibit low ionic conductivity. Gel electrolytes, combining the high ionic conductivity of liquid electrolytes with the mechanical stability of solid electrolytes, have become a current research hotspot. However, the problems of easy freezing and significant decrease in ionic conductivity at low temperatures remain unresolved. Summary of the Invention In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for preparing an electrochromic film, which aims to solve the technical problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention is implemented through the following technical solution: A method for preparing an electrochromic film includes the following steps: Provide a substrate on which Eu³ is prepared + Doped crystalline WO3 substrate; Based on the Eu³ + Mo was prepared by electrodeposition on a doped crystalline WO3 substrate. 6+ Doped amorphous WO3 intermediate layer; To the said Mo 6+ The amorphous WO3 interlayer was aminated, and viologen was covalently bonded to the Mo via chemical bonding. 6+ A covalent substrate is obtained by doping the electrode surface with an amorphous WO3 intermediate layer; A transition layer is introduced onto the covalent substrate, and an electrochemically polymerized polyaniline top layer is prepared based on the covalent substrate to obtain a device cathode; A dual-salt antifreeze gel electrolyte was prepared, and the desired pattern was obtained by exposure and development on the surface of the electrochemically polymerized polyaniline top layer. The dual-salt antifreeze gel electrolyte is cut into gel blocks corresponding to the desired pattern of the device cathode, the gel blocks are assembled on the desired pattern of the device cathode, and the anode is covered on the gel blocks to encapsulate an electrochromic film.

[0005] According to one aspect of the above technical solution, a substrate is provided, on which Eu³ is prepared. + The specific steps for creating a doped crystalline WO3 substrate include: ITO glass is provided, and the ITO glass is ultrasonically cleaned sequentially in acetone, ethanol and deionized water, and then dried with nitrogen gas. Weigh 0.2g~0.3g of Na2WO4·2H2O, add the Na2WO4·2H2O to 30~50ml of deionized water, and stir magnetically at room temperature for 10~20min until the Na2WO4·2H2O dissolves to obtain the first solution; Weigh 0.15~0.30 g of (NH4)2SO4, add the (NH4)2SO4 to the first solution, and continue stirring for 5~20 min to dissolve the (NH4)2SO4 to obtain the second solution; Based on the weighed mass of Na₂WO₄·2H₂O, calculate the required mass of Eu₂O₃ to make Eu³⁺ + The doping amount is 5~15 mol%, and the Eu2O3 is added to the second solution and stirred. During stirring, 3M HCl was added dropwise to adjust the pH of the second solution to 1.0-2.0, thus obtaining the third solution; The third solution was brought to a final volume to obtain a precursor solution, which was then allowed to age at room temperature. The precursor liquid is poured into the liner of the reactor, and the ITO glass is placed in the liner of the reactor with the conductive side facing down. Place the sealed reactor into an electric thermostatic drying oven, set the temperature to 150~180°C, heat the reaction for 2~6 hours, and after the reaction is complete, turn off the oven power and allow it to cool naturally to room temperature. The ITO glass was removed and then sequentially cleaned, dried, and crystallized to obtain Eu³. + Doped crystalline WO3 substrate.

[0006] According to one aspect of the above technical solution, the one based on the Eu³+ Mo was prepared by electrodeposition on a doped crystalline WO3 substrate. 6 + The specific steps for doping an amorphous WO3 intermediate layer include: With the Eu³ + The working electrode is a doped crystalline WO3 substrate / ITO glass, the counter electrode is a Pt sheet, and the reference electrode is Ag / AgCl. Weigh 0.40~0.65g of Na2WO4·2H2O, add the Na2WO4·2H2O to 100~150ml of deionized water, stir magnetically for 10~20min at room temperature, and dissolve to obtain the fourth solution; Based on the mass of Na₂WO₄·2H₂O already weighed, calculate the required mass of Na₂MoO₄·2H₂O to make Mo 6+ The doping concentration is 1~5 mol%; Add the Na2MoO4·2H2O to the fourth solution and stir for 5-10 minutes; During stirring, add 0.30-0.45 M of 30% H2O2 dropwise until the fourth solution changes color, then continue stirring for 10-15 minutes. During stirring, HClO4 is added dropwise to adjust the pH of the fourth solution to 0.8-1.5, thus obtaining the electrodeposition solution. The electrodeposition solution is then allowed to stand for 1-2 hours. Based on the electrodeposition solution, the working electrode is deposited at a constant potential of -0.5 to -0.8 V for 300 to 700 s; Remove the working electrode, rinse and dry at room temperature to obtain Mo. 6+ Doped amorphous WO3 intermediate layer.

[0007] According to one aspect of the above technical solution, the method for the Mo 6+ The amorphous WO3 interlayer was aminated, and viologen was covalently bonded to the Mo via chemical bonding. 6+ A covalent substrate is obtained by doping the electrode surface with an amorphous WO3 intermediate layer. The specific steps include: Carboxylated viologen was synthesized by reacting 0.5-2.0 g of methyl viologen with 1.0-2.0 g of bromoacetic acid under alkaline conditions. Put the Mo 6+ Doped amorphous WO3 interlayer / Eu³ + The electrode made of doped crystalline WO3 bottom layer / ITO glass was immersed in an ethanol solution of 3-aminopropyltriethoxysilane and treated at 55~60℃ for 2~3h to prepare -NH2 groups on the WO3 surface of the material for amination of the electrode. The amination electrode was immersed in a carboxylated viologen solution, and an EDC / NHS catalyst was added. The reaction was carried out at room temperature for 4 hours, so that the carboxylated viologen was covalently linked to the electrode surface through amide bonds. The material was removed from the carboxylated viologen solution, washed, and dried to obtain a covalent substrate.

[0008] According to one aspect of the above technical solution, the specific steps of introducing a transition layer on the covalent substrate include: Prepare a 1.0~1.5wt% PEDOT:PSS stock solution, add 3~10vol% DMSO to the PEDOT:PSS stock solution, stir magnetically for 30~60min, and mix to obtain a PEDOT:PSS solution; The electrode of the covalent substrate is immersed in the PEDOT:PSS solution and electrodeposited at a constant current of 0.05~0.5mA / cm² for 30~300 s. Remove the electrode and anneal for 10-30 minutes to obtain the transition layer.

[0009] According to one aspect of the above technical solution, the preparation of an electrochemically polymerized polyaniline top layer based on the covalent substrate to obtain a device cathode includes the following specific steps: The covalent substrate is used as the working electrode; To prepare a 1M HClO4 solution, add the HClO4 solution to deionized water, stir, and then cool to obtain the prepared HClO4 solution. Take aniline with a concentration range of 0.05~0.2 M, add the aniline to the prepared HClO4 solution, stir magnetically for 10~20 min, and then let stand for 5~10 min to obtain the polymerization solution; The polymerization solution is poured into an electrolytic cell, and the working electrode is electropolymerized in the electrolytic cell by cyclic voltammetry scanning for 5-20 cycles within a potential range of 0~1.0V. After that, the working electrode is removed, cleaned, and dried to obtain the top layer of electrochemically polymerized polyaniline, which is then used to obtain the device cathode.

[0010] According to one aspect of the above technical solution, the specific steps for preparing the dual-salt antifreeze gel electrolyte include: Weigh 0.8-1.2g of acrylamide and 5-20mg of carboxymethyl chitosan. Add the acrylamide and carboxymethyl chitosan to deionized water and stir magnetically until dissolved to obtain a monomer solution. Weigh 0.05~0.15 g of MBA, add it to deionized water and stir to obtain a 0.5~1.5 wt% MBA solution; weigh 0.4~0.6 g of APS, add it to deionized water and stir to obtain a 4~6 wt% APS solution. Add 0.05~0.2 ml of the MBA solution and 0.05~0.2 ml of the APS solution to the monomer solution and stir. Then, degas and mold the mixture to obtain the PAMCS gel matrix. A container is provided, and ethylene glycol with a volume fraction of 20-40 vol%, aluminum perchlorate with a concentration of 1.0-3.0 M, lithium perchlorate with a concentration of 0.2-1.0 M, and methyl viologen with a concentration of 0.005-0.02 M are added to the container. The mixture is then stirred and the pH is adjusted to obtain an immersion solution. The PAMCS gel matrix is ​​immersed in the soaking solution for 12-48 hours, and then the PAMCS gel matrix is ​​taken out and allowed to stand at room temperature for 4-12 hours to obtain a dual-salt antifreeze gel electrolyte.

[0011] The present invention also provides an electrochromic film, which is made by the electrochromic film preparation method described above.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention employs a crystalline / amorphous dual-phase stacked structure as the main body of the electrochromic layer: Eu³ + Doped crystalline WO3 substrate: Utilizing the dense structure and high stability of crystalline materials, this provides long-term cycling stability for the device. Eu³ + Doping broadens ion transport channels through the lattice expansion effect, further optimizing the underlying properties, Mo 6+ Doped amorphous WO3 interlayer: Utilizing the porous structure and rapid ion diffusion of amorphous materials, a fast response channel is provided. Mo 6+ Doping induces lattice distortion, increases the density of active sites, and significantly improves the ion diffusion rate.

[0013] This invention employs a dual-salt antifreeze gel electrolyte, achieving wide-temperature-range operation through the following design: The high ionic conductivity of the dual-salt system provides matching intercalated ions for the WO3 layer. This gel electrolyte enables the device to operate stably in a wide temperature range of -40°C to 60°C, solving the problems of easy freezing at low temperatures and sharp drop in ionic conductivity of traditional gel electrolytes.

[0014] This invention introduces a PEDOT:PSS transition layer between the organic and inorganic layers. The transition layer acts as an "energy level bridge" to match the heterogeneous interface, improve conductivity, and the annealing process further optimizes the film quality. It effectively solves the problems of charge accumulation and transport resistance caused by energy level mismatch at the organic-inorganic interface. This transition layer design significantly improves the efficiency of charge transport across the interface and further shortens the response time. Attached Figure Description

[0015] Figure 1This is a flowchart of the method for preparing the electrochromic film in the first embodiment of the present invention; The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0016] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Several embodiments of the invention are illustrated in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0017] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0019] Please see Figure 1 The figure shows a method for preparing an electrochromic film according to the first embodiment of the present invention, comprising the following steps: S10, providing a substrate, on which Eu³ is prepared... + Doped crystalline WO3 substrate; S20, based on the Eu³ + Mo was prepared by electrodeposition on a doped crystalline WO3 substrate. 6+ Doped amorphous WO3 intermediate layer; S30, for the Mo 6+ The amorphous WO3 interlayer was aminated, and viologen was covalently bonded to the Mo via chemical bonding. 6+ A covalent substrate is obtained by doping the electrode surface with an amorphous WO3 intermediate layer; S40, a transition layer is introduced on the covalent substrate, and an electrochemically polymerized polyaniline top layer is prepared based on the covalent substrate to obtain the device cathode; S50, prepare a dual-salt antifreeze gel electrolyte, and expose and develop the surface of the electrochemically polymerized polyaniline top layer to obtain the desired pattern; S60, the dual-salt antifreeze gel electrolyte is cut into gel blocks corresponding to the desired pattern of the device cathode, the gel blocks are assembled on the desired pattern of the device cathode, and the anode is covered on the gel blocks to encapsulate an electrochromic film. Here, the anode material is a 100μm thick zinc foil.

[0020] Understandably, this invention employs a crystalline / amorphous dual-phase stacked structure as the main body of the electrochromic layer: Eu³ + Doped crystalline WO3 substrate: Utilizing the dense structure and high stability of crystalline materials, this provides long-term cycling stability for the device. Eu³ + Doping broadens ion transport channels through the lattice expansion effect, further optimizing the underlying properties, Mo 6+ Doped amorphous WO3 interlayer: Utilizing the porous structure and rapid ion diffusion of amorphous materials, a fast response channel is provided. Mo 6+ Doping induces lattice distortion, increases the density of active sites, and significantly improves the ion diffusion rate.

[0021] This invention employs a dual-salt antifreeze gel electrolyte, achieving wide-temperature-range operation through the following design: The high ionic conductivity of the dual-salt system provides matching intercalated ions for the WO3 layer. This gel electrolyte enables the device to operate stably in a wide temperature range of -40°C to 60°C, solving the problems of easy freezing at low temperatures and sharp drop in ionic conductivity of traditional gel electrolytes.

[0022] This invention introduces a PEDOT:PSS transition layer between the organic and inorganic layers. The transition layer acts as an "energy level bridge" to match the heterogeneous interface, improve conductivity, and the annealing process further optimizes the film quality. It effectively solves the problems of charge accumulation and transport resistance caused by energy level mismatch at the organic-inorganic interface. This transition layer design significantly improves the efficiency of charge transport across the interface and further shortens the response time.

[0023] Furthermore, a substrate is provided on which Eu³ is prepared. + The specific steps for creating a doped crystalline WO3 substrate include: ITO glass is provided and ultrasonically cleaned sequentially in acetone, ethanol and deionized water, and then dried with nitrogen; this step involves ultrasonic cleaning the ITO glass for 15 minutes in each of the three components. Weigh 0.2g~0.3g of Na2WO4·2H2O, add the Na2WO4·2H2O to 30~50ml of deionized water, and stir magnetically at room temperature for 10~20min until the Na2WO4·2H2O dissolves to obtain the first solution; here, take 0.2g of Na2WO4·2H2O and 40ml of deionized water, and stir magnetically for 15min. Weigh 0.15~0.30 g of (NH4)2SO4, add the (NH4)2SO4 to the first solution, and continue stirring for 5~20 min to dissolve the (NH4)2SO4 to obtain the second solution; here, take 0.15 g of (NH4)2SO4 and continue stirring for 10 min. Based on the weighed mass of Na₂WO₄·2H₂O, calculate the required mass of Eu₂O₃ to make Eu³⁺ + The doping amount is 5-15 mol%. The Eu₂O₃ is added to the second solution and stirred. Eu₂O₃ is sparingly soluble in water and needs to be dissolved in a small amount of concentrated hydrochloric acid before addition, or added directly and stirred for 30-60 minutes to dissolve it under acidic conditions. Here, Eu³⁺ + The doping concentration is 5 mol%; During stirring, 3M HCl is added dropwise to adjust the pH of the second solution to 1.0-2.0, thus obtaining the third solution. In this embodiment, the pH of the second solution is adjusted to 1.5. The adjustment process should be carried out slowly to avoid local over-acidity. The third solution was brought to a constant volume to obtain a precursor solution, which was then aged at room temperature. Aging the prepared precursor solution at room temperature for 12 hours helps to form a stable precursor structure. Pour the precursor solution into the liner of the reactor, and place the ITO glass with the conductive side facing down into the liner of the reactor; place the ITO glass at a 45° angle to the liner wall; if the angle is too small and the surface is flat, it may lead to uneven deposition; if the angle is too large, the substrate may contact the bottom of the liner, affecting growth. Place the sealed reactor into an electric thermostatic drying oven, set the temperature to 150°C, and heat the reaction for 4 hours. After the reaction is complete, turn off the oven power and allow it to cool naturally to room temperature. The ITO glass was removed and then sequentially cleaned, dried, and crystallized to obtain Eu³. + Doped crystalline WO3 substrate.

[0024] Understandably, this step provides a stable crystalline framework for the substrate, Eu³ + Doping widens ion transport channels through lattice expansion.

[0025] Furthermore, the statement based on the Eu³ + Mo was prepared by electrodeposition on a doped crystalline WO3 substrate. 6+ The specific steps for doping an amorphous WO3 intermediate layer include: With the Eu³ +The doped crystalline WO3 substrate / ITO glass serves as the working electrode, the Pt sheet as the counter electrode, and Ag / AgCl as the reference electrode. The working electrode is used to deposit the substrate, the counter electrode is used to complete the circuit loop, and the reference electrode provides a stable reference potential. Weigh 0.40~0.65g of Na2WO4·2H2O, add the Na2WO4·2H2O to 100~150ml of deionized water, and stir magnetically for 10~20min at room temperature to dissolve and obtain the fourth solution; here, take 0.40g of Na2WO4·2H2O, 100ml of deionized water, and stir magnetically for 15min. Based on the mass of Na₂WO₄·2H₂O already weighed, calculate the required mass of Na₂MoO₄·2H₂O to make Mo 6+ The doping amount is 1~5 mol%; here, Mo is taken as... 6+ The doping level is 1 mol% Add the Na₂MoO₄·2H₂O to the fourth solution and stir for 5-10 minutes; here, stir for 5 minutes. During stirring, add 0.30-0.45 M of 30% H2O2 dropwise until the fourth solution changes color, then continue stirring for 10-15 minutes; here, add 0.30 M of 30% H2O2 dropwise and continue stirring for 10 minutes. During stirring, HClO4 is added dropwise to adjust the pH of the fourth solution to 0.8-1.5 to obtain the electrodeposition solution. The electrodeposition solution is then allowed to stand for 1-2 hours. Adjusting the pH of the fourth solution to 1.0 and allowing the electrodeposition solution to stand for 2 hours helps to form a stable peroxytungstate complex. Based on the electrodeposition solution, the working electrode is deposited at a constant potential of -0.5 to -0.8 V for 300 to 700 s; here, the electrodeposition solution is poured into an electrolytic cell, and then the working electrode is immersed in the electrodeposition solution and treated with a potential of -0.6 V; here, the working electrode is at -0.6 V and the deposition time is 300 s. Remove the working electrode, rinse and dry at room temperature to obtain Mo. 6+ Doped amorphous WO3 intermediate layer.

[0026] Understandably, this step provides a rapid ion channel, Mo 6+ Doping induces lattice distortion, and the porous structure serves as a vizigon anchor point.

[0027] Furthermore, the Mo 6+ The amorphous WO3 interlayer was aminated, and viologen was covalently bonded to the Mo via chemical bonding. 6+ A covalent substrate is obtained by doping the electrode surface with an amorphous WO3 intermediate layer. The specific steps include: Carboxylated viologen was synthesized by reacting 0.5–2.0 g of methyl viologen with 1.0–2.0 g of bromoacetic acid under alkaline conditions. Specifically, 0.5 g of methyl viologen and 1.0 g of bromoacetic acid were used, with a molar ratio of 1:2. The two were dissolved in 30 ml of deionized water, and the pH was adjusted to 8.0 with 1 M NaOH. The reaction was carried out in a 60°C water bath for 2–6 hours. After the reaction was completed, the pH was adjusted to 2.0, followed by centrifugation, ethanol washing, and vacuum drying to obtain carboxylated viologen. Put the Mo 6+ Doped amorphous WO3 interlayer / Eu³ + The electrode with doped crystalline WO3 substrate / ITO glass is immersed in an ethanol solution of 3-aminopropyltriethoxysilane and treated at 55~60℃ for 2~3h to prepare -NH2 groups on the WO3 surface of the material for amination of the electrode; the treatment is carried out at 55℃ for 2h. The amination electrode was immersed in a carboxylated viologen solution, and an EDC / NHS catalyst was added. The reaction was carried out at room temperature for 4 hours, allowing the carboxylated viologen to be covalently linked to the electrode surface via amide bonds. The molar ratio of the EDC catalyst was 3 times that of the carboxylated viologen, and the molar ratio of the NHS catalyst was 1 times that of the carboxylated viologen. The carboxylated viologen solution was prepared by dissolving the carboxylated viologen in 0.1M MES buffer (pH 5.0), with a concentration of 0.01M. The material was removed from the carboxylated viologen solution, washed, and dried to obtain a covalent substrate.

[0028] Understandably, this step stabilizes the viologen molecules within the WO3 channels via covalent bonds, preventing physical adsorption from desorbing during long-term cycling and ensuring a long-lasting and stable synergistic effect with the subsequent electrochemical polymerization of polyaniline.

[0029] Furthermore, the specific steps of introducing a transition layer on the covalent substrate include: Prepare a 1.0-1.5 wt% PEDOT:PSS stock solution, add 3-10 vol% DMSO to the PEDOT:PSS stock solution, and stir magnetically for 30-60 min to obtain a PEDOT:PSS solution; here, take a 1.0 wt% PEDOT:PSS solution and 3 vol% DMSO, and stir magnetically for 40 min; The electrode of the covalent substrate was immersed in the PEDOT:PSS solution and electrodeposited at a constant current of 0.05~0.5mA / cm² for 30~300 s; here, a constant current of 0.05 mA / cm² was used for 60 s. The electrode was removed and annealed at 120°C for 20 minutes to obtain the transition layer.

[0030] Understandably, this step addresses the energy level mismatch at the interface between organic polyaniline and inorganic WO3. The work function of the transition layer PEDOT:PSS lies between the two, acting as an "energy level bridge" to facilitate charge transport.

[0031] Furthermore, the preparation of an electrochemically polymerized polyaniline top layer based on the covalent substrate to obtain the device cathode includes the following specific steps: The covalent substrate is used as the working electrode; To prepare a 1M HClO4 solution, add the HClO4 solution to deionized water, stir, and then cool to obtain the prepared HClO4 solution. Take aniline with a concentration range of 0.05~0.2 M, add the aniline to the prepared HClO4 solution, stir magnetically for 10~20 min, and then let stand for 5~10 min to obtain the polymerization solution; here, take 0.05 M aniline, stir magnetically for 15 min, and let stand for 10 min. The polymerization solution is poured into an electrolytic cell, and the working electrode is placed in the electrolytic cell. Electropolymerization is carried out by cyclic voltammetry scanning within the potential range of 0~1.0V for 5-20 cycles. After that, the working electrode is removed, cleaned and dried to obtain the top layer of electrochemically polymerized polyaniline, and then the cathode of the device is obtained; here, a potential of 0.7V is used for 5 cycles.

[0032] Understandably, this step forms a low-voltage main color-changing layer, which works in conjunction with the violet inside the channel to reduce the driving voltage and achieve multi-color display.

[0033] Furthermore, the specific steps for preparing the dual-salt antifreeze gel electrolyte include: Weigh 0.8–1.2 g of acrylamide and 5–20 mg of carboxymethyl chitosan. Add the acrylamide and carboxymethyl chitosan to deionized water and stir magnetically until dissolved to obtain a monomer solution. The amount of deionized water used is 4.0–5.5 mL, matching the amount of acrylamide, and the solid content is controlled at 15–25 wt%. Weigh 0.05~0.15 g of MBA, add it to deionized water and stir to obtain a 0.5~1.5 wt% MBA solution; weigh 0.4~0.6 g of APS, add it to deionized water and stir to obtain a 4~6 wt% APS solution; here, we take 0.05 g of MBA, 0.5 wt% MBA solution, 0.4 g of APS, and 4 wt% APS solution. Add 0.05-0.2 ml of the MBA solution and 0.05-0.2 ml of the APS solution to the monomer solution and stir. Then, degas and mold the mixture to obtain the PAMCS gel matrix. Here, take 0.05 ml of the MBA solution and 0.05 ml of the APS solution. During degassing and molding, place the mixture in a vacuum drying oven and evacuate for 5-15 minutes, or sonicate in an ice bath for 5-10 minutes. Inject the degassed mixture into a mold, which consists of two glass plates with a 1 mm thick silicone gasket sandwiched in between. A container is provided, into which are added 20-40 vol% ethylene glycol, 1.0-3.0 M aluminum perchlorate, 0.2-1.0 M lithium perchlorate, and 0.005-0.02 M methyl viologen. The mixture is then stirred and the pH adjusted to obtain an infusion solution. Here, the solution consists of 20 vol% ethylene glycol, 1.0 M aluminum perchlorate, 0.2 M lithium perchlorate, and 0.005 M methyl viologen. The PAMCS gel matrix was immersed in the soaking solution for 12-48 hours, and then the PAMCS gel matrix was taken out and allowed to stand at room temperature for 4-12 hours to obtain a dual-salt antifreeze gel electrolyte; here, the immersion was 24 hours and the stand was allowed to stand for 6 hours.

[0034] Understandably, in a dual-salt system, Al³ + Li is responsible for the high electrical conductivity of the gel bulk. + Viologen and polyaniline synergistically reduce voltage by providing matching intercalation ions for WO3.

[0035] Finally, the dual-salt antifreeze gel electrolyte is cut into gel blocks corresponding to the required pattern of the device cathode, the gel blocks are assembled on the required pattern of the device cathode, and the anode is covered on the gel blocks to encapsulate an electrochromic film.

[0036] Understandably, the modular gel completely eliminates ion crosstalk, the self-powered design enables low-power operation, and the patterning allows for independent display of multiple areas.

[0037] The second embodiment of the present invention also provides a method for preparing an electrochromic film. The method for preparing the electrochromic film in the second embodiment of the present invention differs from that in the first embodiment in that: In step S10, 0.3g of Na2WO4·2H2O, 0.3g of (NH4)2SO4, and Eu³⁺ are taken. + The doping concentration is 15 mol%; In step S20, 0.65g of Na2WO4·2H2O and Mo are taken. 6+The doping amount was 5 mol%, and the deposition time was 700 s; In step S40, a constant current of 0.5 mA / cm² is used, the aniline concentration is 0.2 M, and 15 scans are performed. In step S50, the concentration of aluminum perchlorate is 3.0 M, the concentration of lithium perchlorate is 1.0 M, and the concentration of methyl viologen is 0.02 M. The remaining parameters are the same as those in the first embodiment; The final devices fabricated using the electrochromic film preparation methods in the first and second embodiments differ from traditional WO3 devices in the following ways:

[0038] It can be seen that the electrochromic films prepared in the two embodiments of this application show a certain improvement in main parameters compared with traditional WO3 devices in the prior art. This improvement in main parameters of traditional WO3 devices is due to the rational design of the process, achieving both high stability and fast response through crystalline / amorphous dual-phase stacking; and through Eu³… + / Mo 6 + Dual doping synergistically optimizes ion transport channels, ensuring long-term synergistic effects through viologen chemical bonding; a PEDOT:PSS transition layer addresses organic-inorganic interface mismatch; and Al³⁺ is used to further enhance the synergistic effect. + / Li + Dual-salt gel: balances high conductivity with low-temperature adaptability; modular gel + photolithographic patterning: achieves high-precision crosstalk-free display.

[0039] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0040] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for preparing an electrochromic film, characterized in that, The steps include the following: Provide a substrate on which Eu³ is prepared + Doped crystalline WO3 substrate; Based on the Eu³ + Mo was prepared by electrodeposition on a doped crystalline WO3 substrate. 6+ Doped amorphous WO3 intermediate layer; To the said Mo 6+ The amorphous WO3 interlayer was aminated, and viologen was covalently bonded to the Mo via chemical bonding. 6+ A covalent substrate is obtained by doping the electrode surface with an amorphous WO3 intermediate layer; A transition layer is introduced onto the covalent substrate, and an electrochemically polymerized polyaniline top layer is prepared based on the covalent substrate to obtain a device cathode; A dual-salt antifreeze gel electrolyte was prepared, and the desired pattern was obtained by exposure and development on the surface of the electrochemically polymerized polyaniline top layer. The dual-salt antifreeze gel electrolyte is cut into gel blocks corresponding to the required pattern of the cathode of the device, the gel blocks are assembled on the required pattern of the cathode of the device, and the anode is covered on the gel blocks to encapsulate an electrochromic film. The Eu³ + Doped crystalline WO3 substrate was fabricated on ITO glass, and the Mo... 6+ The amorphous WO3 interlayer was aminated, and viologen was covalently bonded to the Mo via chemical bonding. 6+ A covalent substrate is obtained by doping the electrode surface with an amorphous WO3 intermediate layer. The specific steps include: Carboxylated viologen was synthesized by reacting 0.5-2.0 g of methyl viologen with 1.0-2.0 g of bromoacetic acid under alkaline conditions. Put the Mo 6+ Doped amorphous WO3 interlayer / Eu³ + The electrode with doped crystalline WO3 substrate / ITO glass is immersed in an ethanol solution of 3-aminopropyltriethoxysilane and treated at 55~60℃ for 2~3h to prepare -NH2 groups on the WO3 surface of the material for amination of the electrode. The amination electrode was immersed in a carboxylated viologen solution, and an EDC / NHS catalyst was added. The reaction was carried out at room temperature for 4 hours, so that the carboxylated viologen was covalently linked to the electrode surface through amide bonds. The material was removed from the carboxylated viologen solution, washed, and dried to obtain a covalent substrate; The specific steps of introducing a transition layer on the covalent substrate include: Prepare a 1.0~1.5wt% PEDOT:PSS stock solution, add 3~10vol% DMSO to the PEDOT:PSS stock solution, stir magnetically for 30~60min, and mix to obtain a PEDOT:PSS solution; The electrode of the covalent substrate is immersed in the PEDOT:PSS solution and electrodeposited at a constant current of 0.05~0.5mA / cm² for 30~300 s. Remove the electrode and anneal for 10-30 minutes to obtain the transition layer.

2. The method for preparing the electrochromic film according to claim 1, characterized in that, The method provides a substrate on which Eu³ is fabricated. + The specific steps for creating a doped crystalline WO3 substrate include: ITO glass is provided, and the ITO glass is ultrasonically cleaned sequentially in acetone, ethanol and deionized water, and then dried with nitrogen gas. Weigh 0.2g~0.3g of Na2WO4·2H2O, add the Na2WO4·2H2O to 30~50ml of deionized water, and stir magnetically at room temperature for 10~20min until the Na2WO4·2H2O dissolves to obtain the first solution; Weigh 0.15~0.30 g of (NH4)2SO4, add the (NH4)2SO4 to the first solution, and continue stirring for 5~20 min to dissolve the (NH4)2SO4 to obtain the second solution; Based on the weighed Na₂WO₄·2H₂O, calculate the required mass of Eu₂O₃ to make Eu³⁺ + The doping amount is 5~15 mol%, and the Eu2O3 is added to the second solution and stirred. During stirring, 3M HCl was added dropwise to adjust the pH of the second solution to 1.0-2.0, thus obtaining the third solution; The third solution was brought to a final volume to obtain a precursor solution, which was then allowed to age at room temperature. The precursor liquid is poured into the liner of the reactor, and the ITO glass is placed in the liner of the reactor with the conductive side facing down. Place the sealed reactor into an electric thermostatic drying oven, set the temperature to 150~180°C, heat the reaction for 2~6 hours, and after the reaction is complete, turn off the oven power and allow it to cool naturally to room temperature. The ITO glass was removed and then sequentially cleaned, dried, and crystallized to obtain Eu³. + Doped crystalline WO3 substrate.

3. The method for preparing the electrochromic film according to claim 2, characterized in that, The basis of Eu³ + Mo was prepared by electrodeposition on a doped crystalline WO3 substrate. 6+ The specific steps for doping an amorphous WO3 intermediate layer include: With the Eu³ + The working electrode is a doped crystalline WO3 substrate / ITO glass, the counter electrode is a Pt sheet, and the reference electrode is Ag / AgCl. Weigh 0.40~0.65g of Na2WO4·2H2O, add the Na2WO4·2H2O to 100~150ml of deionized water, stir magnetically for 10~20min at room temperature, and dissolve to obtain the fourth solution; Based on the mass of Na₂WO₄·2H₂O already weighed, calculate the required mass of Na₂MoO₄·2H₂O to make Mo 6+ The doping concentration is 1~5 mol%; Add the Na2MoO4·2H2O to the fourth solution and stir for 5-10 minutes; During stirring, add 0.30-0.45 M of 30% H2O2 dropwise until the fourth solution changes color, then continue stirring for 10-15 minutes. During stirring, HClO4 is added dropwise to adjust the pH of the fourth solution to 0.8-1.5, thus obtaining the electrodeposition solution. The electrodeposition solution is then allowed to stand for 1-2 hours. Based on the electrodeposition solution, the working electrode is deposited at a constant potential of -0.5 to -0.8 V for 300 to 700 s; Remove the working electrode, rinse and dry at room temperature to obtain Mo. 6+ Doped amorphous WO3 intermediate layer.

4. The method for preparing the electrochromic film according to claim 1, characterized in that, The preparation of an electrochemically polymerized polyaniline top layer based on the covalent substrate to obtain the device cathode includes the following specific steps: The covalent substrate is used as the working electrode; To prepare a 1M HClO4 solution, add the HClO4 solution to deionized water, stir, and then cool to obtain the prepared HClO4 solution. Take aniline with a concentration range of 0.05~0.2 M, add the aniline to the prepared HClO4 solution, stir magnetically for 10~20 min, and then let stand for 5~10 min to obtain the polymerization solution; The polymerization solution is poured into an electrolytic cell, and the working electrode is electropolymerized in the electrolytic cell by cyclic voltammetry scanning for 5-20 cycles within a potential range of 0~1.0V. After that, the working electrode is removed, cleaned, and dried to obtain the top layer of electrochemically polymerized polyaniline, which is then used to obtain the device cathode.

5. The method for preparing the electrochromic film according to claim 1, characterized in that, The specific steps for preparing the dual-salt antifreeze gel electrolyte include: Weigh 0.8-1.2g of acrylamide and 5-20mg of carboxymethyl chitosan. Add the acrylamide and carboxymethyl chitosan to deionized water and stir magnetically until dissolved to obtain a monomer solution. Weigh 0.05~0.15 g of MBA, add it to deionized water and stir to obtain a 0.5~1.5 wt% MBA solution; weigh 0.4~0.6 g of APS, add it to deionized water and stir to obtain a 4~6 wt% APS solution. Add 0.05~0.2 ml of the MBA solution and 0.05~0.2 ml of the APS solution to the monomer solution and stir. Then, degas and mold the mixture to obtain the PAMCS gel matrix. A container is provided, and ethylene glycol with a volume fraction of 20-40 vol%, aluminum perchlorate with a concentration of 1.0-3.0 M, lithium perchlorate with a concentration of 0.2-1.0 M, and methyl viologen with a concentration of 0.005-0.02 M are added to the container. The mixture is then stirred and the pH is adjusted to obtain an immersion solution. The PAMCS gel matrix is ​​immersed in the soaking solution for 12-48 hours, and then the PAMCS gel matrix is ​​taken out and allowed to stand at room temperature for 4-12 hours to obtain a dual-salt antifreeze gel electrolyte.

6. An electrochromic film, characterized in that, It is made by the method for preparing the electrochromic film according to any one of claims 1 to 5.

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