An electrochromic polymer of a triphenylamine derivative, and a preparation method and application thereof

Abstract

This invention belongs to the field of polymer technology and discloses an electrochromic polymer of triphenylamine derivative, its preparation method, and its application. The electrochromic polymer has the structure shown in formula (1): where X is an integer greater than 0 and n is a non-zero integer. This electrochromic polymer has advantages such as low bandwidth, rich colors, fast response time, and high coloring efficiency.

Description

Technical Field

[0001] This invention belongs to the field of polymer technology, and specifically relates to an electrochromic polymer of triphenylamine derivative, its preparation method and application. Background Technology

[0002] Electrochromic materials exhibit persistent and significant reversible color changes under the application of a low voltage. In recent years, electrochromic materials have attracted considerable attention in many promising applications, such as smart windows for energy-efficient buildings, self-dimming rearview mirrors for automobiles, information displays, and electrochromic electronic skins, including energy storage devices such as electrochromic supercapacitors. A typical electrochromic device (ECD) has a multilayer structure consisting of a transparent conductor, an electrochromic film, an electrolyte layer, and an ion storage film. During application, the electrochromic layer can alter its optical properties (typically the light absorption rate in the visible light region) and can be easily restored to its original bleached state.

[0003] Organic electrochromic materials (organic small molecule and conductive polymer-based electrochromic materials) have advantages such as wide color range, high coloring efficiency, fast response speed, easy processing and low cost, which can make up for the shortcomings of inorganic electrochromic materials and have become a hot topic in the field of electrochromic research.

[0004] However, existing organic electrochromic materials still suffer from problems such as high bandwidth, slow response time, and low coloring efficiency.

[0005] Therefore, there is an urgent need to provide an electrochromic polymer with low bandwidth, fast response time, and high coloring efficiency. Summary of the Invention

[0006] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes an electrochromic polymer of triphenylamine derivative, its preparation method, and its application. The electrochromic polymer has advantages such as low bandwidth, rich colors, fast response time, and high coloring efficiency.

[0007] A first aspect of the present invention provides an electrochromic polymer.

[0008] Specifically, an electrochromic polymer has the structure shown in formula (1):

[0009]

[0010] Where X is

[0011] n is an integer greater than 0.

[0012] Preferably, n is an integer from 1 to 10000, such as 100-6000 or 500-4000.

[0013] Preferably, the structure of the electrochromic polymer is shown in formula (2) or formula (3):

[0014]

[0015] A second aspect of the present invention provides a method for preparing an electrochromic polymer.

[0016] Specifically, a method for preparing an electrochromic polymer includes the following steps:

[0017] (1) Dissolve the active precursor and supporting electrolyte in a solvent and then add them to the electrolytic cell of the three-electrode system;

[0018] (2) The electrochromic polymer was deposited on the working electrode of a three-electrode system by electrochemical polymerization reaction using a constant potential method;

[0019] The active precursor is

[0020] Preferably, the constant potential method includes the constant current method or the cyclic voltammetry method.

[0021] Preferably, the concentration of the active precursor in the solvent is 0.001-1 mol / L, more preferably 0.001-0.1 mol / L; even more preferably 0.005-0.05 mol / L; and may also be 0.008-0.02 mol / L.

[0022] Preferably, the solvent is at least one of dichloromethane (CH2Cl2), chloroform (CHCl3), or acetonitrile (MeCN).

[0023] Preferably, the concentration of the supporting electrolyte is 0.01-1 mol / L; more preferably 0.05-0.5 mol / L; and even more preferably 0.08-0.2 mol / L.

[0024] Preferably, the supporting electrolyte is at least one of tetrabutylammonium hexafluorophosphate, tetrabutylammonium tetrafluoroborate, or lithium perchlorate.

[0025] Preferably, in the three-electrode system, the Ag / AgCl electrode is used as the reference electrode, the platinum wire is used as the counter electrode, and the Pt / ITO conductive glass is used as the working electrode.

[0026] Preferably, the Ag / AgCl electrode is prepared by the following method: placing a silver electrode in a 4-8 mol / L HCl solution and electrolyzing it at a constant potential of 1-2V for 50-200s, an AgCl layer is generated on the surface of the silver electrode, thus obtaining the Ag / AgCl electrode.

[0027] Preferably, in the method for preparing the electrochromic polymer, the deposition potential of the electrochemical polymerization reaction is 0.5-1V; more preferably 0.85-0.95V.

[0028] Preferably, the electrochemical polymerization reaction is carried out under a protective gas atmosphere. In a specific embodiment of the invention, the protective gas is selected from argon or helium.

[0029] Preferably, a washing step is performed after the electrochemical polymerization reaction deposition is completed; the washing reagent is preferably acetonitrile. The purpose of washing is to remove the electrolyte and generated oligomers from the electrochromic polymer.

[0030] The electropolymerization chemical reaction process in step (2) is shown in the following reaction equation:

[0031]

[0032] "Electrochemical Polymerization" refers to electrochemical polymerization.

[0033] Electrochemical polymerization (referred to as "e-polymerization") is carried out in a one-chamber three-electrode system.

[0034] Preferably, the preparation process of the active precursor includes the following steps:

[0035] The active precursor is prepared by the following steps: Knovenagel condensation reaction of compound FTPA and at least one of compound 1, compound 2 or compound 3 in a catalyst and solvent to obtain the active precursor;

[0036] The structural formula of the compound FTPA is:

[0037] The structural formula of compound 1 is:

[0038] The structural formula of compound 2 is:

[0039] The structural formula of compound 3 is:

[0040] Preferably, in the method for preparing the active precursor, the molar ratio of FTPA to compound 1, compound 2 or compound 3 is 1:(1-1.5); more preferably 1:(1.2-1.25).

[0041] Preferably, in the method for preparing the active precursor, the temperature of the Knovenagel condensation reaction is 50-100℃; more preferably 60-70℃.

[0042] Preferably, in the method for preparing the active precursor, the Knovenagel condensation reaction takes 12-18 hours; more preferably 14-16 hours.

[0043] Preferably, in the method for preparing the active precursor, the catalyst includes pyridine.

[0044] Preferably, in the method for preparing the active precursor, the solvent includes at least one of tetrahydrofuran (THF), toluene (Tol), N,N-dimethylformamide (DMF), or CH3Cl.

[0045] Preferably, in the method for preparing the active precursor, a chromatographic separation and purification step is performed after washing; the chromatographic separation and purification preferably uses a silica gel column.

[0046] A third aspect of the present invention provides an application of an electrochromic polymer.

[0047] An electrochromic device comprising the aforementioned electrochromic polymer.

[0048] Preferably, the electrochromic device includes a display device or a light-transmitting device.

[0049] More preferably, the electrochromic device includes at least one of a display, electrochromic glass, a smart window, or a rearview mirror.

[0050] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0051] (1) The electrochromic polymer of this invention is a DAD-type triphenylamine derivative electrochromic material. By modifying the para-position of triphenylamine with strong electron-withdrawing groups, the absorption spectrum of the electrochromic polymer can be adjusted, thereby changing the color of the polymer and obtaining a polymer with rich colors. This gives the electrochromic polymer advantages such as low bandwidth, rich colors, fast response time, and high coloring efficiency.

[0052] (2) The electrochromic polymer of the present invention is modified at the para position of the triphenylamine derivative by a strong electron-withdrawing group through the Knovenagel condensation reaction, thereby enhancing the interaction between the donor and the acceptor, improving the optical contrast and coloring efficiency of the electrochromic polymer, and having a lower bandwidth and a wider absorption range, which greatly expands its application range, especially in the preparation of electrochromic devices.

[0053] (3) The electrochromic polymer of the present invention can be observed to have a stable and reversible color change from dark green to dark blue or from light green to dark blue under the action of an applied voltage, and has good electrochromic properties, including fast response time, high coloring efficiency and good optical transmittance. Attached Figure Description

[0054] Figure 1 The electrochemical spectrograms of the electrochromic polymers in Examples 1-2 in the MeCN-Bu4NPF6 (0.1 mol / L) system are shown.

[0055] Figure 2 The transmittance-time curves of the electrochromic polymers in Examples 1-2 in the MeCN-Bu4NPF6 (0.1 mol / L) system are shown.

[0056] Figure 3 This illustrates the short-term memory effect of the electrochromic polymers in the MeCN-Bu4NPF6 (0.1 mol / L) system in Examples 1-2. Detailed Implementation

[0057] To enable those skilled in the art to more clearly understand the technical solution described in this invention, the following embodiments are provided for illustration. Electrochromic materials have many data parameters that can be used to evaluate their performance in the laboratory stage, such as ultraviolet absorbance, transmittance, coloring efficiency, response time, and open-circuit memory effect, all of which are important parameters for evaluating whether a material is suitable for practical application.

[0058] Ultraviolet absorbance refers to the change in polymer properties during doping and dedoping processes. Macroscopically, this is manifested as a change in absorbance in the ultraviolet-visible spectrum. Different applied voltages and different degrees of polymer doping will result in corresponding changes in the color and brightness of the film. However, this property can only qualitatively analyze whether a material has electrochromic properties, and cannot subjectively judge or quantitatively analyze the quality of the material's electrochromic properties.

[0059] Transmittance refers to the change in the optical properties of a material under an applied voltage, which is quantitatively detected in an ultraviolet spectrometer and is represented by ΔT.

[0060] Coloring efficiency: refers to the ratio of the change in absorbance of an electrochromic material at a given wavelength to the change that results in the injection or extraction of all electrons.

[0061] For an electrochromic material, coloring efficiency is an important parameter for evaluating its performance. Studying the coloring efficiency of conductive polymers requires considering the electrochemical and spectral changes of the electrochromic film. The calculation formula is as follows:

[0062] ΔOD = log(Tox / Tred);

[0063] Qd = (Qox + Qred) / S;

[0064] CE = ΔOD / Qd;

[0065] Where Tox is the transmittance of the electrochromic material in the oxidized state; Tred is the transmittance of the electrochromic material in the reduced state; Qox is the charge amount during the oxidation process; Qred is the charge amount during the reduction process; and S is the area of ​​the working electrode.

[0066] Response time refers to the time required for a material to achieve a 95% change in transmittance when a square wave voltage changes its potential under an applied voltage. A shorter response time indicates a faster conversion time, which better meets the requirements of practical applications. However, this value is related to many factors, including the conductivity of the substrate, the inherent properties of the material, the conductivity of the system, the concentration of free ions in the system, and the ion migration rate. Furthermore, different working environments in applications require different conversion times.

[0067] The memory effect refers to the property of a material to maintain its doped or dedoped state under open-circuit conditions with an applied voltage. When a fully doped or fully dedoped voltage is applied to a material, and then the applied voltage is disconnected, the time-transmittance curve of the material in a UV spectrometer is observed. Under normal circumstances, because the dopant ions in the material are not bound under open-circuit conditions, they will automatically dissociate into the solution, causing changes in the material's color and transmittance, thus indicating the degree of change in the material's memory effect.

[0068] The absorption sites of a polymer determine its color, which is of great significance for the preparation of electrochromic polymers of various colors. Response time is also an important parameter of electrochromic materials, as it reveals the speed at which dopant ions enter the polymer backbone during the doping process.

[0069] Unless otherwise specified, the raw materials, reagents or devices used in the following examples are available from conventional commercial sources or can be obtained by existing known methods.

[0070] The examples disclose DAD-type electrochromic materials derived from triphenylamine derivatives and their preparation methods. The preparation method first uses 4-(diphenylamino)benzaldehyde as a raw material to prepare 4-(bis(4-bromophenyl)amino)benzaldehyde. 4-(bis(4-bromophenyl)amino)benzaldehyde is then mixed with an EDOT (3,4-ethylenedioxythiophene) derivative to undergo a Stille coupling reaction, generating 4-(bis(4-(2,3-dihydrothiophene[3,4-b][1,4]dioxane-5-yl)phenyl)amino)benzaldehyde (FTPA). Then, FTPA undergoes a Knovenagel condensation reaction with 1H-indole-1,3(2H)-dione or 2-(3-oxo-2,3-dihydroindole-1-methylene)maronium nitrile to generate the target products named ITPA and ICTPA, respectively. These are then subjected to an electrochemical polymerization reaction to obtain an electrochromic polymer that can achieve multicolor state transitions over a wider voltage range and exhibits good stability.

[0071] Example 1: Synthesis of monomers and electrochromic polymers

[0072] (1) Synthesis of a single FTPA:

[0073]

[0074] NBS (N-bromo-succinimide) solution (9.26 g, in 50 mL DMF) was added dropwise to ice-cold 4-(diphenylamino)benzaldehyde solution (2.5 g, in 25 mL DMF) to complete the reaction. Water was added to stop the reaction, and the product was extracted with DCM (dichloromethane) dried with anhydrous magnesium sulfate. The product was concentrated under vacuum and purified by column chromatography to obtain a solid product (4-(bis(4-bromophenyl)amino)benzaldehyde, 5.59 g), with a yield of 65%.

[0075] Then, the 4-(bis(4-bromophenyl)amino)benzaldehyde (1.92 g), tributyl(2,3-dihydrothiophene[3,4-b][1,4]dioxan-5-yl)stanane (4.82 g, 11.17 mmol), and Pd(PPh3)4 (0.20 g, 0.17 mmol) obtained above were placed in a 250 mL flask and subjected to three vacuum and argon purging treatments. Under reduced pressure, 80 mL of toluene and 20 mL of DMF were added to the flask. The resulting mixture was refluxed and stirred at 120 °C for 48 hours, then cooled to room temperature. Toluene was removed by rotary evaporation, and the mixture was extracted with dichloromethane and washed with saturated sodium chloride solution. Dichloromethane was removed by rotary evaporation to give a yellow solid (1.23 g), which was then subjected to column chromatography to give the product (FTPA) in 50% yield.

[0076] (2) Synthesis of monomer ITPA:

[0077]

[0078] 0.1 g (0.18 mmol) of FTPA and 0.031 g of compound 1 were placed in a 50 mL flask. Under argon protection, 30 mL of CH3Cl and 0.5 mL of pyridine were added. The mixture was refluxed and stirred at 70 °C for 12 h. After the reaction was completed, the mixture was allowed to stand at room temperature. CH3Cl was removed by rotary evaporation. After removing CH3Cl, 10 mL of anhydrous ethanol was added. The anhydrous ethanol and pyridine were removed by rotary evaporation. The product (ITPA) was obtained by column chromatography, yielding 0.08 g of a red solid, with a yield of 65%.

[0079] (3) Synthesis of PITPA electrochromic polymer:

[0080]

[0081] Electrochemical polymerization was carried out in a three-electrode system. A silver / silver chloride electrode (silver wire electrolyzed at a constant potential of 1.5V for 100s in 6mol / L HCl solution to generate an AgCl coating) was used as the reference electrode, a platinum wire as the counter electrode, and an ITO conductive glass as the working electrode. 10 mL of dichloromethane was used as the electrolyte, ITPA (0.01 mol / L) as the monomer, and tetrabutylphosphine hexafluoride (0.1 mol / L) as the supporting electrolyte. Polymerization was carried out using a potentiostatic method with a polymerization potential of 0.91V and a polymerization time of 100s. The electrodeposited PITPA electrochromic polymer film was immersed and rinsed with acetonitrile to remove the electrolyte solution and oligomers generated in the PITPA electrochromic polymer.

[0082] Electrochromic performance study

[0083] (1) The prepared PITPA electrochromic polymer film deposited on ITO conductive glass was placed in a three-electrode electrolytic cell containing a 0.1 mol / L tetrabutylphosphine dichloromethane solution (the solvent was acetonitrile MeCN, denoted as the MeCN-Bu4NPF6 system). The working electrode was the ITO conductive glass with the PITPA electrochromic polymer film attached, the counter electrode was a platinum sheet, and the reference electrode was an Ag / AgCl electrode. The voltage applied to the working electrode was adjusted by an electrochemical workstation using a constant potential method. At the same time, the change trend of the absorption spectrum of the PITPA electrochromic polymer film under different voltages was recorded by a UV-Vis spectrometer, thus obtaining the spectroelectrochemical spectrum of the PITPA electrochromic polymer film.

[0084] The spectroelectrochemical spectra of the PMTPA electrochromic polymer film are shown below. Figure 1 ( Figure 1In Figure (a), “Absorbance” represents absorbance and “Wavelength” represents wavelength. The PMTPA electrochromic polymer exhibits absorption peaks at 353 nm and 640 nm. With increasing applied voltage, the absorption intensity at 353 nm decreases, while the absorption intensity at 640 nm initially increases and then decreases. A distinct and broad absorption band is observed in the near-infrared region of the oxidized PITPA electrochromic polymer, which should be attributed to the increased absorption of polarons and bipolarons. The color of the PITPA electrochromic polymer changes from dark green in the neutral state to dark blue in the oxidized state.

[0085] (2) The transmittance of PITPA electrochromic polymer film in doped and neutral states at a specific wavelength under square wave potential is measured by using a UV-Vis spectrophotometer, thereby calculating optical contrast, response time, etc. The UV-Vis spectrophotometer records the time-transmittance curve, and the electrochemical workstation records the time-current curve. The coloring efficiency can also be calculated based on these two curves.

[0086] The transmittance-time curves of the PITPA electrochromic polymer at 1100 nm and 496 nm were tested. The response time and coloring efficiency calculated from the time-transmittance curves are shown in Table 1. As can be seen from Table 1, the PITPA electrochromic polymer has a fast response time and high coloring efficiency.

[0087] Table 1: Electrochromic parameters of PITPA electrochromic polymer

[0088]

[0089] The optical transmittance of the PMTPA electrochromic polymer was studied using chronoamperometry at wavelengths of 1100 nm and 496 nm. During the experiment, the time interval between potential step changes was 5 s. Figure 2 ( Figure 2 In Figure (a), “Transmittance” represents transmittance and “Time” represents time. At both wavelengths, the PMTPA electrochromic polymer exhibited certain optical contrast and good optical stability.

[0090] Using a potentiostatic method, a voltage was applied to the working electrode with an electrochemical workstation for 10 seconds, followed by 2 seconds every 100 seconds. Simultaneously, a UV-Vis spectrometer was used to record the transmittance trends of the PMTPA electrochromic polymer in its oxidized and reduced states at the maximum absorption peak, thus obtaining the short-term memory effect spectrum of the PMTPA electrochromic polymer. The short-term memory effect of PITPA was tested at a wavelength of 1100 nm. Voltages of 0.2 V and 1 V were applied, and the transmittance changes of the PMTPA electrochromic polymer in the neutral and doped states were recorded. The results are as follows: Figure 3 ( Figure 3 As shown in (a), “Transmittance” represents transmittance and “Time” represents time. It was found that the transmittance of the PMTPA electrochromic polymer changed very little in the neutral and doped states, which indicates that the PMTPA electrochromic polymer has a good short-term memory effect.

[0091] Example 2: Synthesis of monomers and polymers

[0092] (1) Synthesis of monomeric FTPA, the process is the same as that of the synthesis of monomeric FTPA in Example 1.

[0093] (2) Synthesis of Compound 2

[0094]

[0095] 1.1 g (7.5 mmol) of compound 1, 0.8 g (9.75 mmol) of anhydrous sodium acetate, and 1 g (15.74 mmol) of malononitrile were placed in a 100 mL flask and stirred at room temperature for 40 minutes. The resulting mixture was poured into water, and hydrochloric acid was added to adjust the pH of the mixture to 1. The mixture was then extracted with dichloromethane and washed with saturated sodium chloride solution. Dichloromethane was removed by rotary evaporation, and column chromatography was used to obtain 1.16 g of solid product (compound 2), with a yield of 80%.

[0096] (3) Synthesis of monomer ICTPA

[0097]

[0098] 0.1 g (0.18 mmol) of FTPA and 0.042 g of compound 2 were placed in a 50 mL flask. Under argon protection, 30 mL of CH3Cl and 0.5 mL of pyridine were added. The mixture was refluxed and stirred at 70 °C for 12 h. After the reaction was completed, the mixture was allowed to stand at room temperature. CH3Cl was removed by rotary evaporation. Then, 10 mL of anhydrous ethanol was added, and anhydrous ethanol and pyridine were removed by rotary evaporation. Column chromatography yielded 0.098 g of a blue solid product, with a yield of 65%.

[0099] (4) Synthesis of PICTPA electrochromic polymer:

[0100]

[0101] Electrochemical polymerization was carried out in a one-chamber three-electrode system. The working electrode was ITO conductive glass, the counter electrode was a platinum sheet, and the reference electrode was an Ag / AgCl electrode (silver wire was electrolyzed at a constant potential of 1.5V for 100s in 6mol / L HCl solution to generate an AgCl coating on the surface).

[0102] Using 10 mL of dichloromethane as the electrolyte, ICTPA (0.01 mol / L) as the monomer, and tetrabutylphosphine hexafluoride (0.1 mol / L) as the supporting electrolyte, polymerization was carried out using a potentiostatic method with a polymerization potential of 0.9 V and a polymerization time of 100 s. The PICTPA electrochromic polymer film obtained by electrochemical polymerization deposition was rinsed with acetonitrile to remove the electrolyte solution and oligomers generated in the polymer.

[0103] Electrochromic performance study

[0104] (1) The prepared PICTPA electrochromic polymer film deposited on ITO conductive glass was placed in a three-electrode electrolytic cell containing a 0.1 mol / L tetrabutylphosphine dichloromethane solution (acetonitrile MeCN). The working electrode was an ITO conductive glass coated with the PITPA electrochromic polymer film, the counter electrode was a platinum sheet, and the reference electrode was an Ag / AgCl electrode. The voltage applied to the working electrode was adjusted by an electrochemical workstation using a constant potential method. At the same time, the change trend of the absorption spectrum of the PICTPA electrochromic polymer film under different voltages was recorded by a UV-Vis spectrometer, thus obtaining the spectral electrochemical spectrum of the PICTPA electrochromic polymer film.

[0105] The results are as follows Figure 1 As shown in Figure b, the PICTPA electrochromic polymer film exhibits absorption peaks at 400 nm and 620 nm. With increasing applied voltage, the absorption intensity at 400 nm decreases, while the absorption intensity at 620 nm initially increases and then decreases. A distinct and broad absorption band is observed in the near-infrared region of the oxidized PICTPA electrochromic polymer film, which should be attributed to the increased absorption of polarons and bipolarons. The color of the PICTPA electrochromic polymer film changes from light green in the neutral state to deep blue in the oxidized state.

[0106] (2) The transmittance-time curves of the PICTPA electrochromic polymer film at 1100 nm and 427 nm were tested. The response time and coloring efficiency calculated from the time-transmittance curves are shown in Table 2. As can be seen from Table 2, the PICTPA electrochromic polymer film has a fast response time and a high coloring efficiency.

[0107] Table 2: Electrochromic parameters of PICTPA electrochromic polymer films

[0108]

[0109] The optical transmittance of the PICTPA electrochromic polymer film was studied using chronoamperometry at wavelengths of 1100 nm and 427 nm. During the experiment, the time interval between potential step changes was 5 s. Figure 2As shown in (b), the PICTPA electrochromic polymer film exhibits certain optical contrast and good optical stability at both wavelengths. Furthermore, optical transmittance has a significant impact on the color change of the PICTPA electrochromic polymer film, which can change from a light green in the completely dedoped state to a deep blue in the doped state.

[0110] (3) The short-term memory effect of the PICTPA electrochromic polymer film was tested at a wavelength of 1100 nm. Voltages of 0 V and 1 V were applied, and the transmittance changes of the PICTPA electrochromic polymer film in the neutral and doped states were recorded, such as... Figure 3 As shown in (b), the transmittance of the PICTPA electrochromic polymer film is found to be very small in the neutral and doped states, which indicates that the polymer has a poor short-term memory effect.

[0111] Existing triphenylamine star-shaped polymers cannot have their material properties altered by modifying intermediates. The electrochromic polymer of this invention offers greater structural tunability and freedom. By adjusting parameters such as the intermediate structure, chain length, side chain structure, and branching degree of the triphenylamine chain polymer, its optical and electrochemical properties can be controlled, achieving unexpected technical effects and thus realizing better electrochromic performance.

Claims

1. An electrochromic polymer, characterized in that, It has the structure shown in equation (1): Where X is n is an integer greater than 0.

2. The electrochromic polymer according to claim 1, characterized in that, The structure of the electrochromic polymer is shown in formula (2) or formula (3) below:

3. The method for preparing the electrochromic polymer according to claim 1 or 2, characterized in that, Includes the following steps: (1) Dissolve the active precursor and supporting electrolyte in a solvent and then add them to the electrolytic cell of the three-electrode system; (2) The electrochromic polymer was deposited on the working electrode of a three-electrode system by electrochemical polymerization reaction using a constant potential method; The active precursor is 4. The preparation method according to claim 3, characterized in that, The constant potential method includes the constant current method or the cyclic voltammetry method.

5. The preparation method according to claim 3, characterized in that, The concentration of the active precursor in the solvent is 0.001-1 mol / L; and / or the concentration of the supporting electrolyte is 0.01-1 mol / L; and / or the supporting electrolyte is at least one of tetrabutylammonium hexafluorophosphate, tetrabutylammonium tetrafluoroborate, or lithium perchlorate.

6. The preparation method according to claim 3, characterized in that, The potential for deposition via electrochemical polymerization is 0.5-1V.

7. The preparation method according to claim 3, characterized in that, The preparation process of the active precursor includes the following steps: The active precursor is obtained by Knovenagel condensation reaction of compound FTPA and at least one of compound 1, compound 2 or compound 3 in a catalyst and solvent. The structural formula of the compound FTPA is: The structural formula of compound 1 is: The structural formula of compound 2 is: The structural formula of compound 3 is:

8. The preparation method according to claim 7, characterized in that, In the preparation method of the active precursor, the molar ratio of FTPA to compound 1, compound 2 or compound 3 is 1:(1-1.5); and / or, the temperature of the Knovenagel condensation reaction is 50-100℃; and / or, the time of the Knovenagel condensation reaction is 12-18 hours.

9. An electrochromic device, characterized in that, Includes the electrochromic polymer as described in claim 1 or 2.

10. The electrochromic device according to claim 9, characterized in that, The electrochromic device includes at least one of a display, electrochromic glass, a smart window, or a rearview mirror.

Images