A multi-color electrochromic device and a method for manufacturing the same
By constructing a multilayer electrochromic device using poly(3,4-ethylenedioxythiophene) and polytetraphenylbenzidine derivatives, the problems of insufficient stability and compatibility in the prior art are solved, and high stability and precise color control of multicolor electrochromic devices are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SOUTH CHINA UNIV OF TECH
- Filing Date
- 2026-01-07
- Publication Date
- 2026-06-02
AI Technical Summary
Existing multicolor electrochromic devices have shortcomings in terms of stability and compatibility. In particular, electrochromic devices based on tungsten trioxide and N,N,N',N'-tetra(p-phenylmethyl)benzidine experience performance degradation after multiple cycles, making it difficult to achieve high stability and multicolor conversion.
Poly(3,4-ethylenedioxythiophene) was used as the blue electrochromic material and polytetraphenylbenzidine derivatives were used as the orange electrochromic material. Polytetraphenylbenzidine derivatives were prepared by polycondensation and their redox reaction was controlled at different voltages. Combined with surfactants and electrolyte layers, multilayer electrochromic devices were constructed.
It achieves multiple color transitions from transparent to blue, black, green and finally back to transparent, improving the stability and color control accuracy of the device and significantly improving the cycle stability of the device.
Smart Images
Figure CN122131527A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrochromic technology, and in particular to a multi-color electrochromic device and its preparation method. Background Technology
[0002] Electrochromic devices, which modulate the optical properties of materials through electric fields, have wide applications in fields such as smart windows, flexible displays, and wearable devices. With technological advancements, multi-color electrochromic devices need to balance dynamic color rendering with the requirements of a black state (such as privacy protection and high-contrast display), and the technical approach of achieving black based on the principle of complementary colors has become a research focus.
[0003] Currently, the mainstream approach to achieving black electrochromic properties is the multi-color overlay method, which uses red, green, and blue electrochromic layers to collaboratively color the material and create black. A typical structure requires at least three functional layers stacked, with the transmittance of each primary color controlled by independent voltages (e.g., red + green + blue = black). However, each additional functional layer significantly increases the complexity of the manufacturing process and the requirements for equipment. Therefore, there is an urgent need to develop electrochromic devices that can achieve multi-color conversion using only two materials.
[0004] Based on the principle that black is achieved through complementary blue and orange colors, previous studies have used tungsten trioxide and N,N,N',N'-tetraphenylbenzidine derivatives to construct electrochromic devices for multi-color conversion (Transparent-to-black electrochromic smart windows based on N,N,N',N'-Tetraphenylbenzidine derivatives and tungsten trioxide with high adjustment ability for visible and near-infrared light). Although this scheme simplifies the structure to four layers by dissolving TPB-4Me in the electrolyte layer, it still has significant drawbacks: tungsten trioxide, as an inorganic material, has excellent stability, while N,N,N',N'-tetraphenylbenzidine, as a small organic molecule, has poor stability. The two are not compatible enough, and the device performance is prone to degradation after repeated cycling.
[0005] In conclusion, there is an urgent need to research and develop a multi-color electrochromic device to solve the problems existing in current products and meet the current market development needs. Summary of the Invention
[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a multi-color electrochromic device and its preparation method. This invention obtains polytetraphenylbenzidine derivatives through polycondensation and utilizes the color characteristics exhibited when the first and second electrochromic layers undergo redox reactions at different voltages to achieve multiple color conversions of the electrochromic device from transparent to blue, black, green and finally back to transparent.
[0007] The purpose of this invention is to provide a multi-color electrochromic device, which comprises, from bottom to top: a first ITO conductive glass, a first electrochromic layer, an electrolyte layer, a second electrochromic layer, and a second ITO conductive glass. in, The first electrochromic layer comprises poly(3,4-ethylenedioxythiophene); The second electrochromic layer includes a polytetraphenylbenzidine derivative; The polytetraphenylbenzidine derivative has the following structure: R is selected from alkyl or alkyl derivatives, or alkoxy or alkoxy derivatives, or aromatic ring derivatives; R1 and R2 are each independently selected from alkyl or alkyl derivatives, or alkoxy or alkoxy derivatives; n is a natural number selected from 1 to 10000.
[0008] Furthermore, the poly(3,4-ethylenedioxythiophene) (PEDOT) has the following structure: n is a natural number selected from 1 to 10000.
[0009] Furthermore, the first electrochromic layer and the second electrochromic layer also include additives.
[0010] Furthermore, the additives include surfactants.
[0011] Furthermore, the sheet resistance of the first ITO conductive glass and the second ITO conductive glass is 10-80 ohm / sq.
[0012] Furthermore, the electrolyte layer includes an electrolyte, a polymer monomer, a photoinitiator, a solvent, and a thickener.
[0013] Furthermore, the electrolyte is selected from one or more of lithium perchlorate, lithium bis(trifluoromethanesulfonyl)imide, tetrabutylammonium hexafluorophosphate, potassium hexafluorophosphate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-3-methylimidazolium tetrafluoroborate, and 1-vinyl-3-methylimidazolium acetate.
[0014] Furthermore, the polymer monomer is selected from one or more of polyethylene glycol diacrylate, methyl methacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, and ethoxylated trimethylolpropane triacrylate.
[0015] Furthermore, the photoinitiator is selected from one or more of 2,4,6-trimethylbenzoylphenylphosphonate, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 2,2-dimethoxy-2-phenylacetophenone, and 2-hydroxy-2-methyl-1-phenyl-1-propanone.
[0016] Furthermore, the solvent is selected from one or more of propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, diphenyl carbonate, dibutyl carbonate, and butylene carbonate.
[0017] Furthermore, the tackifier is selected from one or more of polymethyl methacrylate, polybutyl methacrylate, polyvinylidene fluoride-co-hexafluoropropylene, and polyethylene oxide.
[0018] Another object of the present invention is to provide a method for preparing the multi-color electrochromic device, the method comprising the following steps: S1. Compound 1 and Compound 2 are blended and reacted in an inert atmosphere to obtain a polytetraphenylbenzidine derivative. S2. The poly(3,4-ethylenedioxythiophene) and surfactant I are blended, coated onto the first ITO conductive glass, and dried to obtain the first electrochromic layer. S3. The polytetraphenylbenzidine derivative, surfactant II, additives and solvent are mixed and coated onto the second ITO conductive glass and dried to obtain the second electrochromic layer. S4. Mix the electrolyte, polymer monomer, photoinitiator, solvent, and thickener to obtain an electrolyte mixed solution; S5. A gap is reserved between the first electrochromic layer and the second electrochromic layer. The electrolyte mixture solution is injected into the gap and cured to obtain the multicolor electrochromic device. in, Compound 1 has the following structure: R1 and R2 are each independently selected from alkyl or alkyl derivatives, or alkoxy or alkoxy derivatives; Compound 2 has the following structure: X1 and X2 are each independently selected from one of the following: fluorine atom, chlorine atom, bromine atom, iodine atom, hydroxyl group, and amino group; R is selected from alkyl or alkyl derivatives, or alkoxy or alkoxy derivatives, or aromatic ring derivatives.
[0019] Further, in step S1, the molar mass ratio of compound 1 to compound 2 is (1-2):(1-2).
[0020] Furthermore, in step S1, the reaction temperature is 100-120°C.
[0021] Further, in step S2, the mass ratio of the poly(3,4-ethylenedioxythiophene) to surfactant I is (90-99):(1-10).
[0022] Furthermore, in step S3, the drying temperature is 100-140°C.
[0023] Further, in step S4, the mass ratio of the electrolyte to the polymer monomer is (1-3):(35-42).
[0024] Furthermore, in step S5, the thickness of the interval is 20-200 μm.
[0025] Further, in step S3, the surfactant II is selected from one or more of polymethylsiloxane, polyether-modified polydimethylsiloxane, and polyester-modified polydimethylsiloxane.
[0026] Further, in step S3, the auxiliary agent is selected from one or more of hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, trimellitic anhydride, and phthalic anhydride.
[0027] Further, in step S3, the solvent is selected from one or more of dimethyl sulfoxide, N,N-dimethylacetamide, and N,N-dimethylformamide.
[0028] The present invention has the following beneficial effects: This invention selects poly(3,4-ethylenedioxythiophene) as the blue electrochromic material and polytetraphenylbenzidine derivative as the orange electrochromic material. The poly(3,4-ethylenedioxythiophene) film is transparent blue in its reduced state; as the applied voltage increases to 2.0V, its color gradually transitions from transparent blue to dark blue. The polytetraphenylbenzidine derivative film reaches its first reduction potential at 1.5V, changing its color from transparent and colorless to orange; it reaches its second reduction potential at 2.7V, further changing its color to blue or green. Therefore, within the voltage range of 1.5V to 2.5V, precise control of various color changes can be achieved by adjusting the ratio of poly(3,4-ethylenedioxythiophene) to polytetraphenylbenzidine derivative. Through color matching resulting from the redox reactions of the two electrochromic materials at different voltages, multiple color transitions of the electrochromic device from transparent to blue, black, green, and finally back to transparent are realized. Simultaneously, polymerization of the small-molecule tetraphenylbenzidine derivative (i.e., compound 1) significantly improves the stability of the electrochromic device. Attached Figure Description
[0029] Figure 1 The color change test of the embodiment shows the transmittance change of the device under different voltages.
[0030] Figure 2 The color change test of the embodiment is shown at different voltages for L. * a * b * Value change.
[0031] Figure 3 The following are photographs of the device at 0V and 2V voltages for color change testing according to the embodiment, along with the corresponding L... * a * b * value.
[0032] Figure 4 The color change test of the embodiment is shown under different voltages via L * a * b * The color fitting image obtained is worthwhile.
[0033] Figure 5 The results of the transmittance test by the spectrometer for the embodiment are shown.
[0034] Figure 6 The cyclic stability test results of the embodiment are shown.
[0035] Figure 7 The results of the comparative cycle stability test are shown.
[0036] Figure 8 The structure of a multicolor electrochromic device according to an embodiment is shown. Detailed Implementation
[0037] To more clearly illustrate the technical solution of the present invention, the following embodiments are provided. Unless otherwise stated, the raw materials, reactions, and post-processing methods appearing in the embodiments are all commercially available raw materials and technical methods well known to those skilled in the art.
[0038] The terms "preferred," "more preferably," and "more suitable" used in this invention refer to embodiments of the invention that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this invention.
[0039] It should be understood that, except in any operational instance or otherwise indicated, the amounts or all figures representing ingredients used, for example, in the specification and claims, should be understood to be modified by the term "about" in all cases. Therefore, unless otherwise stated, the numerical parameters set forth in the following specification and appended claims are approximate values varying according to the desired performance to be obtained according to the invention.
[0040] The embodiments of the present invention use the following raw materials: NMP, N-methylpyrrolidone, M103248, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.
[0041] PEDOT, PH1000 raw dispersion (PEDOT mass fraction of 1%), was purchased from Shanghai Jingnian Chemical Co., Ltd.
[0042] The first ITO conductive glass has a sheet resistance of 10 ohm / sq and dimensions of 50mm×50mm×1.1mm.
[0043] The second ITO conductive glass has a sheet resistance of 10 ohm / sq and dimensions of 50mm×50mm×1.1mm.
[0044] FS-30 is surfactant I, purchased from Guangzhou Jianyi Chemical Import & Export Co., Ltd.
[0045] Byk 333 is surfactant II, purchased from Dongyang Chemical (Hong Kong) Co., Ltd.
[0046] Hexahydrophthalic anhydride, an additive, C124721, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.
[0047] DMSO, dimethyl sulfoxide, additive, D103274, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.
[0048] DMAc, N,N-dimethylacetamide, solvent, D108096, were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.
[0049] PC is propylene carbonate, solvent, P105723, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.
[0050] PMMA is polymethyl methacrylate, a tackifier, brand name 20201245751255, purchased from Taicang Kaida Plastic Raw Materials Co., Ltd.
[0051] LiTFSI is lithium bis(trifluoromethanesulfonyl)imide, electrolyte, W830100, purchased from Anhui Zesheng Technology Co., Ltd.
[0052] PEGDA 700 is polyethylene glycol diacrylate, a polymer monomer, P816111, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.
[0053] 1173 is 2-hydroxy-2-methyl-1-phenyl-1-propanone, a photoinitiator, BD22472, purchased from Shanghai Bid Pharmaceutical Technology Co., Ltd.
[0054] Example A multi-color electrochromic device, with the structure as follows: Figure 4 As shown, the multi-color electrochromic device comprises, from bottom to top: a first ITO conductive glass, a first electrochromic layer, an electrolyte layer, a second electrochromic layer, and a second ITO conductive glass; The method for preparing the multi-color electrochromic device includes the following steps: S1. Tetraphenylbenzidine derivative (compound 1) and adipic acid (compound 2) are blended in a 1:1 molar mass ratio and dissolved in a pyridine and NMP mixed solution with a volume ratio of 1:50 to make the mass fraction of tetraphenylbenzidine derivative 20%. The mixture is evacuated and purged with nitrogen three times until no more bubbles are generated in the solution. The oil bath temperature is heated to 110℃ and reacted for 3 hours. After the reaction is stopped, methanol is added dropwise to precipitate the product. The methanol solution of the precipitate is separated by suction filtration to obtain the crude product. After washing with hot water three times, the product is placed in an 80℃ oven and vacuum dried for 18 hours to obtain the polytetraphenylbenzidine derivative. in, The tetraphenylbenzidine derivative (compound 1) has the following structure: The polytetraphenylbenzidine derivative has the following structure: S2. PEDOT, FS-30, and DMSO are mixed in a mass ratio of 90:5:5. After stirring evenly and allowing to stand to remove bubbles, a PEDOT coating solution is obtained. The cleaned first ITO conductive glass is fixed on a coating machine, and the PEDOT coating solution is poured onto the first ITO conductive glass. A PEDOT wet film is obtained by scraping with a doctor blade at a speed of 1.5 m / min (the thickness of the wet film is controlled at 50 μm). After drying in a 160℃ oven for 1 hour, the first electrochromic layer is obtained. S3. Weigh a certain amount of polytetraphenylbenzidine derivative, Byk 333, and hexahydrophthalic anhydride, add DMAc and stir evenly to prepare a coating solution with a polytetraphenylbenzidine derivative content of 50 mg / g, a Byk 333 content of 50 mg / g, and a hexahydrophthalic anhydride content of 50 mg / g. Fix the cleaned second ITO conductive glass on the coating machine, pour the coating solution onto the second ITO conductive glass, and use a doctor blade to coat the polytetraphenylbenzidine derivative wet film (wet film thickness controlled at 150 μm) at a speed of 1.5 m / min. After drying in a 120℃ oven for 1 h, the second electrochromic layer is obtained. S4. First, weigh PC and PMMA, dissolve them thoroughly by sonication, then add LiTFSI and PEGDA 700 in sequence, stir and dissolve at room temperature, and finally add 1173. Control the mass ratio of LiTFSI, PEGDA 700, 1173, PC and PMMA to 3:35:1:46:15. After stirring thoroughly, an electrolyte mixed solution is obtained. S5. Construct electrode tabs on one side of the first electrochromic layer and the second electrochromic layer respectively. Fix them between the first and second electrochromic layers with polyimide tape (50mm×5mm×50μm) to form the thickness of the electrolyte layer (thickness controlled at 50μm). Inject the electrolyte mixture between the first and second electrochromic layers at a power of 80W / cm². 2 After curing under a UV lamp for 30 seconds, the multi-color electrochromic device is obtained.
[0055] Comparative Example The difference between the comparative example and the embodiment is that steps S1 and S3 are deleted, and steps S4 and S5 are modified as follows: S4. First, weigh PC and PMMA, dissolve them thoroughly by sonication, then add LiTFSI and PEGDA 700 sequentially, stir and dissolve at room temperature, and finally add 1173. Control the mass ratio of LiTFSI, PEGDA 700, 1173, PC, and PMMA to 3:35:1:46:15. After thorough stirring, an electrolyte mixed solution is obtained. Weigh a certain amount of TPB-4Me and add it to 20mL of NMP. After thorough sonication, a TPB-4Me / NMP solution with a concentration of 0.1mol / L is obtained. Mix the TPB-4Me / NMP solution with the electrolyte mixed solution at a mass ratio of 1:2, stir evenly, and let stand to remove bubbles to obtain an electrolyte solution containing TPB-4Me. S5. Electrode tabs are constructed on one side of the first electrochromic layer and the second ITO conductive glass, respectively. Polyimide tape (50mm × 5mm × 50μm) is used to fix the electrode between the first electrochromic layer and the second ITO conductive glass as the thickness of the electrolyte layer (thickness controlled at 50μm). The electrolyte solution containing TPB-4Me is injected between the first electrochromic layer and the second ITO conductive glass at a power of 80W / cm². 2 After curing under a UV lamp for 30 seconds, the multi-color electrochromic device is obtained.
[0056] The remaining components and preparation methods are the same as in the examples.
[0057] Test case Performance tests were conducted on the examples and comparative examples.
[0058] Test method: Color change test: Using a programmable linear DC regulated power supply (GPD-3303S, GW Instek (Suzhou) Co., Ltd.) as the external power supply, a voltage of 0V to 2.5V was applied to the electrochromic device, and the CIE L of the device was obtained on a haze meter (CS-700, Hangzhou Caipu Technology Co., Ltd.). * a * b * Color coordinates, through L * a * b * Color coordinate fitting yields color changes under different voltages.
[0059] Transmittance variation test: Using a programmable linear DC regulated power supply (GPD-3303S, GW Instek (Suzhou) Co., Ltd.) as the external power supply, the transmittance values of the device under conditions of 0V to 2V were obtained on an optical transmittance meter (LS108H, Shenzhen Linshang Technology Co., Ltd.) or a spectrometer.
[0060] Cyclic stability test: An electrochromic device cyclic tester (KV-EC-7500, Zhuhai Kaiwei Instrument Equipment Co., Ltd.) was used as the external power supply. The applied voltage was set to 2.0V and -2.0V, with a cycle count of 5000. The duration at 2.0V was 15 seconds, and the duration at -2.0V was 15 seconds. The optical transmittance values at ±2.0V were recorded using an optical transmittance meter.
[0061] Test results: The test results are shown in Table 1. Figure 1-7 As shown.
[0062] Figure 1 The color change test of the embodiment shows the transmittance change of the device under different voltages.
[0063] Figure 2 The color change test of the embodiment is shown at different voltages for L. * a * b * Value change.
[0064] Figure 3 The following are photographs of the device at 0V and 2V voltages for color change testing according to the embodiment, along with the corresponding L... * a * b * value.
[0065] Figure 4 The color change test of the embodiment is shown under different voltages via L * a * b * The color fitting image obtained is worthwhile.
[0066] Figure 5 The results of the transmittance test by the spectrometer for the embodiment are shown.
[0067] Figure 6 The cyclic stability test results of the embodiment are shown.
[0068] Figure 7 The results of the comparative cycle stability test are shown.
[0069] Figure 8 The structure of a multicolor electrochromic device according to an embodiment is shown.
[0070] Table 1 Test Results The color change of the single-component black electrochromic device obtained in the example is as follows: Figure 1-4As shown, the device appears transparent at 0V; when the voltage rises to 1.6V, it turns bluish-purple; as the voltage continues to increase to 2.2V, the device changes from bluish-purple to black; when the voltage is further increased to 2.5V, the device turns green. The results of transmittance changes and cycle stability are shown in Table 1. Figure 6-7 As shown in Table 1, the transmittance is the result of the optical transmittance measuring instrument. The test data shows that at 2V, the device in the example is in a colored state, with a T value of 1%, appearing as black; at 0V, the device is transparent, with a T value of approximately 55.8%; the device can be stably cycled for approximately 5000 times, exhibiting good cycle stability.
[0071] Numerical results show that the comparative example has higher transmittance and contrast. However, because the added TPB-4Me is a small molecule and does not use the polytetraphenylbenzidine derivative of the present invention, its stability is poor. This is because TPB-4Me is more likely to migrate under the action of an electric field, causing TPB-4Me to accumulate at both poles during the device cycling process, resulting in the failure of color matching with the PEDOT layer. This leads to a significantly lower number of cycles compared to the example. This indicates that the preparation method of the present invention has both better stability and contrast.
[0072] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.
[0073] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A multi-color electrochromic device, characterized in that, The multi-color electrochromic device comprises, from bottom to top: a first ITO conductive glass, a first electrochromic layer, an electrolyte layer, a second electrochromic layer, and a second ITO conductive glass; in, The first electrochromic layer comprises poly(3,4-ethylenedioxythiophene); The second electrochromic layer includes a polytetraphenylbenzidine derivative; The polytetraphenylbenzidine derivative has the following structure: R is selected from alkyl or alkyl derivatives, or alkoxy or alkoxy derivatives, or aromatic ring derivatives; R1 and R2 are each independently selected from alkyl or alkyl derivatives, or alkoxy or alkoxy derivatives; n is a natural number selected from 1 to 10000.
2. The multi-color electrochromic device according to claim 1, characterized in that, The first electrochromic layer and the second electrochromic layer also include additives.
3. The multi-color electrochromic device according to claim 2, characterized in that, The additives include surfactants.
4. The method for preparing the multi-color electrochromic device according to any one of claims 1-3, characterized in that, The method for preparing the multi-color electrochromic device includes the following steps: S1. Compound 1 and Compound 2 are blended and reacted in an inert atmosphere to obtain a polytetraphenylbenzidine derivative. S2. The poly(3,4-ethylenedioxythiophene) and surfactant I are blended, coated onto the first ITO conductive glass, and dried to obtain the first electrochromic layer. S3. The polytetraphenylbenzidine derivative, surfactant II, additives and solvent are mixed and coated onto the second ITO conductive glass and dried to obtain the second electrochromic layer. S4. Mix the electrolyte, polymer monomer, photoinitiator, solvent, and thickener to obtain an electrolyte mixed solution; S5. A gap is reserved between the first electrochromic layer and the second electrochromic layer. The electrolyte mixture solution is injected into the gap and cured to obtain the multicolor electrochromic device. in, Compound 1 has the following structure: R1 and R2 are each independently selected from alkyl or alkyl derivatives, or alkoxy or alkoxy derivatives; Compound 2 has the following structure: X1 and X2 are each independently selected from one of the following: fluorine atom, chlorine atom, bromine atom, iodine atom, hydroxyl group, and amino group; R is selected from alkyl or alkyl derivatives, or alkoxy or alkoxy derivatives, or aromatic ring derivatives.
5. The method for preparing the multi-color electrochromic device according to claim 4, characterized in that, In step S1, the molar mass ratio of compound 1 to compound 2 is (1-2):(1-2).
6. The method for preparing the multi-color electrochromic device according to claim 4, characterized in that, In step S1, the reaction temperature is 100-120℃.
7. The method for preparing the multi-color electrochromic device according to claim 4, characterized in that, In step S2, the mass ratio of poly(3,4-ethylenedioxythiophene) to surfactant I is (90-99):(1-10).
8. The method for preparing the multi-color electrochromic device according to claim 4, characterized in that, In step S3, the drying temperature is 100-140℃.
9. The method for preparing the multi-color electrochromic device according to claim 4, characterized in that, In step S4, the mass ratio of the electrolyte to the polymer monomer is (1-3):(35-42).
10. The method for preparing the multi-color electrochromic device according to claim 4, characterized in that, In step S5, the thickness of the interval is 20-200 μm.