Conjugated polymer as well as preparation method and application thereof

Abstract

The invention discloses a conjugated polymer of chlorobenzene, o-dichlorobenzene or m-dichlorobenzene and EDOT as well as a preparation method and application of the conjugated polymer, and belongs to the field of polymer electrochromic materials. Chlorine atoms are introduced into different active sites of benzene to serve as intermediates, EDOT serves as a strong electron donating group, and the obtained conjugated polymer has the advantages of being wider in redox peak, good in optical contrast ratio, short in response time, high in coloring efficiency, good in stability and the like.

Description

Technical Field

[0001] The invention belongs to the field of polymer electrochromic materials, and in particular relates to a conjugated polymer and a preparation method and application thereof. Background Art

[0002] Electrochromism (EC) refers to the phenomenon that the color or optical properties (absorbance / transmittance / reflectivity, etc.) of a material undergoes a reversible and stable change under the action of an applied voltage. Among electrochromic materials, electrochromic conjugated polymers (ECPs) have attracted much attention due to their advantages such as variable colors, good processability, low cost, fast response speed and high coloring efficiency. They have broad application prospects in the fields of smart windows, information encryption, electronic paper, spacecraft thermal control and military camouflage.

[0003] At present, there are many materials that can be used as electrochromic intermediates, such as benzo[c][1,2,5]thiadiazole (BT), thiadiazole[3,4-c]pyridine, benzotriazole, thiophene pyrazine and quinoline. However, there are few reports using benzene derivatives as intermediates. Phenyl electrochromic materials have attracted attention due to their excellent electrochromic properties, ease of preparation and excellent stability. Substitution on the phenyl unit plays a crucial role in fine-tuning the optoelectronic and electronic properties of polymers (band gap, molecular weight, inter-chain and intra-chain interactions, charge transport, etc.). Among all halogen substituents, fluorine is the most widely used element to fine-tune polymer properties and has been very successful in improving polymer electrochromism. Despite these achievements, the fluorine exchange reaction of fluorinated materials has low yields and involves toxic intermediates, so the final materials are expensive and are not the best choice for scaling up industrial large-scale production.

[0004] Therefore, it is of great significance to provide a high-performance phenyl polymer electrochromic material with low cost, low toxicity and large-scale production. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention provides a conjugated polymer. The conjugated polymer introduces chlorine atoms as conjugated intermediates in different active sites of benzene and EDOT as a strong electron-donating group, so that the obtained conjugated polymer has a broader redox peak, and has good optical contrast, fast response time, high coloring efficiency, good stability and the like when used in electrochromic materials.

[0006] The invention also provides a method for preparing the conjugated polymer.

[0007] The invention also provides an electrochromic material.

[0008] The present invention also provides an application of the conjugated polymer in an electrochromic device.

[0009] The invention also provides a method for preparing the conjugated polymer.

[0010] According to one aspect of the present invention, a conjugated polymer is provided, which has any one of the following molecular structures:

[0011]

[0012] In the present invention, the chlorine atom substitution on the phenyl unit not only reduces the HOMO / LUMO energy levels of the monomer and its polymer, but also reduces the initial oxidation potential of the monomer. The chlorination strategy of the present invention has several advantages in regulating the π-electron behavior of organic semiconductors: (1) As the second most electronegative element in the halogen family, chlorine atoms affect the intermolecular and intramolecular interactions; (2) Chlorination of the phenyl unit can reduce the HOMO and LUMO energy levels; (3) Chlorinated molecules are easily available and low cost.

[0013] The conjugated polymer of chlorobenzene, o-dichlorobenzene or m-dichlorobenzene connected to EDOT provided by the present invention has various positive effects on its photoelectric properties, energy level, flatness and crystallinity due to the presence of non-covalent halogen bonds. When used in electrochromic materials, it has the characteristics of low bandwidth, rich colors, fast response time, high coloring efficiency, etc.

[0014] According to another aspect of the present invention, a method for preparing the above conjugated polymer is provided, wherein the conjugated polymer is prepared from an active precursor by an electrochemical polymerization method; the active precursor has any one of the following structural formulas:

[0015]

[0016] The preparation method of the invention is simple, the raw materials are readily available, the production cost is low, and it is easy to industrialize and mass produce.

[0017] In some embodiments of the present invention, the method for preparing the active precursor comprises: under the protection of an inert gas, subjecting the intermediate compound to a stannic compound of EDOT in a catalyst and a solvent for a Stille / Suzuki cross-coupling reaction, thereby obtaining the active precursor;

[0018] The intermediate compound is 1,4-dibromo-2,5-dichlorobenzene, 1,4-dibromo-2,3-dichlorotoluene or 1,4-dibromo-2-chlorobenzene.

[0019] In some preferred embodiments of the present invention, the protective atmosphere comprises nitrogen.

[0020] In some preferred embodiments of the present invention, the tin hydrocarbon compound of EDOT is 5-tributyltin-3,4-vinyldioxythiophene, ie, tributyl(2,3-dihydro[3,4-b][1,4]dioxin-5-yl)stannane.

[0021] In some preferred embodiments of the present invention, the catalyst is at least one of tetrakistriphenylphosphine palladium (Pd(PPh3)4) or bistriphenylphosphine palladium dichloride (Pd(PPh3)2Cl2).

[0022] In some preferred embodiments of the present invention, the solvent includes at least one of toluene and N,N-dimethylformamide (DMF).

[0023] In some preferred embodiments of the present invention, the molar ratio of the intermediate compound, the tin hydrocarbon compound of EDOT and the catalyst is 1:2-3:0.03-0.1; for example, the molar ratio of the intermediate compound, the tin hydrocarbon compound of EDOT and the catalyst can be about 1:2.5:0.04, about 1:2.5:0.05 or about 1:2.5:0.07.

[0024] In some preferred embodiments of the present invention, the reaction temperature is 100°C to 120°C; for example, it can be about 100°C, about 105°C, about 110°C or about 120°C.

[0025] In some preferred embodiments of the present invention, the reaction time is 24 h to 48 h; for example, it can be about 24 h, about 28 h, about 32 h, about 36 h, about 40 h or about 48 h.

[0026] According to some specific embodiments of the present invention, the active precursor is prepared by any one of the following reaction equations.

[0027]

[0028]

[0029] In some embodiments of the present invention, the method for preparing the active precursor further includes the step of purifying the product obtained by the reaction, including but not limited to rotary evaporation, reduced pressure distillation and column chromatography (eg, by silica gel chromatography column).

[0030] In some preferred embodiments of the present invention, the electrochemical polymerization method comprises using a solution containing the active precursor as an electrolyte solution and adopting a constant potential method, a constant current method or a cyclic voltammetry method to electrodeposit the conjugated polymer thin film material.

[0031] In some preferred embodiments of the present invention, the electrolyte solution further comprises a solvent.

[0032] In some more preferred embodiments of the present invention, the solvent includes at least one of dichloromethane (CH2Cl2), chloroform (CHCl3) or acetonitrile (MeCN).

[0033] In some preferred embodiments of the present invention, the electrolyte solution further contains a supporting electrolyte.

[0034] In some more preferred embodiments of the present invention, the supporting electrolyte includes at least one of tetrabutylammonium hexafluorophosphate (Bu4NPF6), tetrabutylammonium tetrafluoroborate (Bu4NBF4) or lithium perchlorate (LiClO4).

[0035] In some preferred embodiments of the present invention, the concentration of the active precursor in the electrolyte solution is 0.001 to 0.01 mol·L -1 ; For example, about 0.001 mol·L -1 , about 0.002 mol·L -1 , about 0.005 mol·L -1 or about 0.008 mol·L -1 , about 0.01 mol·L -1 .

[0036] In some preferred embodiments of the present invention, the concentration of the supporting electrolyte is 0.05 to 0.15 mol·L -1 Preferably, the concentration of the supporting electrolyte is 0.075 to 0.125 mol·L -1 In a more preferred embodiment, the concentration of the supporting electrolyte is about 0.1 mol·L -1 .

[0037] In some specific embodiments of the present invention, the conjugated polymer of the benzene derivative linked to EDOT is prepared by one of the following reaction equations:

[0038]

[0039]

[0040] In some embodiments of the present invention, the electrochemical polymerization method is carried out in a three-electrode system consisting of a reference electrode, a counter electrode and a working electrode.

[0041] In some preferred embodiments of the present invention, the working electrode comprises a glassy carbon electrode / ITO conductive glass, the counter electrode comprises a platinum wire, and the reference electrode comprises an Ag / AgCl electrode.

[0042] In some preferred embodiments of the present invention, the electrochemical polymerization method uses a constant potential method for electrodeposition.

[0043] In some more preferred embodiments of the present invention, the potential of the electrodeposition is 0.8V to 1.2V; for example, it can be about 0.8V, about 0.9V, about 1.0V, about 1.1V or about 1.2V; preferably 0.8 to 1.0V.

[0044] In some more preferred embodiments of the present invention, the electrodeposition time is 80s to 200s; for example, the electrodeposition time is about 80s, about 100s, about 120s, about 140s, about 160s, about 180s or about 200s; preferably 100-160s.

[0045] In some more preferred embodiments of the present invention, the electrodeposition potential is about 0.9 V and the time is about 120 s.

[0046] According to yet another aspect of the present invention, an electrochromic material is provided, which comprises the above-mentioned conjugated polymer or the conjugated polymer prepared by the above-mentioned preparation method.

[0047] According to another aspect of the present invention, the application of the above conjugated polymer or the conjugated polymer prepared by the above preparation method in an electrochromic device is proposed. The electrochromic device includes but is not limited to electrochromic glass.

[0048] The beneficial technical effects of the present invention are:

[0049] 1. The conjugated polymer of the present invention has a conjugated structure, and the energy band gap of the polymer can be adjusted by the π-π* conjugation strength, thereby changing the color of the polymer.

[0050] 2. The conjugated polymer of the present invention has good planarity based on benzene. Compared with traditional intermediates, chlorobenzene, o-dichlorobenzene and m-dichlorobenzene are easy to obtain and have higher economic efficiency, making them have greater potential in practical applications. The conjugated polymer of the benzene derivative of the present invention combined with the strong electron-donating group of 3,4-ethylenedioxythiophene (EDOT) has a shorter response time, good coloring efficiency, good optical contrast and distinct color change through electrochromic performance characterization. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0052] Figure 1 P(Y2Cl-EDOT) of Example 1 was dissolved in MeCN-Bu4NPF6 (0.1 mol·L -1 ) system.

[0053] Figure 2 The transmittance-time curves of P(Y2Cl-EDOT) of Example 1 at 537nm, 890nm and 1100nm.

[0054] Figure 3 To implement 2, P(T2Cl-EDOT) was prepared in MeCN-Bu4NPF6 (0.1 mol·L -1 ) system.

[0055] Figure 4 The transmittance-time curves of P(T2Cl-EDOT) of Example 2 at 465nm, 730nm and 1100nm.

[0056] Figure 5 To implement 3, P(Cl-EDOT) was prepared in MeCN-Bu4NPF6 (0.1 mol·L -1 ) system.

[0057] Figure 6 The transmittance-time curves of P(Cl-EDOT) of Example 3 at 465nm, 690nm and 1100nm. DETAILED DESCRIPTION

[0058] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0059] As used herein, when used in connection with a numerical value, the term "about" is intended to include a set or range of numerical values. For example, "about" means a numerical range of ±10%, ±5%, ±2%, ±1%, ±0.5%, ±0.2%, or ±0.1% of the numerical value. In one embodiment, the term "about" refers to a numerical range of 5% more or less than a specific value. In another embodiment, the term "about" refers to a numerical range of 2% more or less than a specific value. In another embodiment, the term "about" refers to a numerical range of 1% more or less than a specific value.

[0060] The test methods used in the examples are conventional methods unless otherwise specified; the materials, reagents, etc. used, unless otherwise specified, can be obtained from commercial sources. Unless otherwise specified, the same parameter values ​​in each example are the same. The examples described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0061] In the present invention, the coloring efficiency refers to the ratio of the change in absorbance of the electrochromic material at a given wavelength to the total electron injection or extraction.

[0062] For an electrochromic material, coloring efficiency is an important parameter for evaluating material performance. The coloring efficiency of conductive polymers should be studied in combination with the electrochemical and spectral changes of the electrochromic film. The calculation formula is as follows:

[0063] ΔOD=log(T ox / T red ) (1)

[0064] Q d =(Q ox +Q red ) / S (2)

[0065] CE=ΔOD / Q d (3)

[0066] Among them, T ox is the transmittance of the electrochromic material in the oxidized state; T red is the transmittance of the electrochromic material in the reduced state; Q ox is the charge during the oxidation process; Q red is the amount of charge during the reduction process; S is the area of ​​the working electrode.

[0067] Example 1

[0068] (1) Synthesis of Y2Cl-EDOT active precursor

[0069]

[0070] Under nitrogen atmosphere, 2,5-dibromo-1,4-dichlorobenzene (1.64mmol, 0.5g), tributyl (2,3-dihydro [3,4-b] [1,4] dioxin-5-yl) stannane (4.1mmol, 1.772g), and catalyst Pd (PPh3) 2Cl2 (0.076mmol, 0.066g) were placed in a 250mL single-necked flask, and dry toluene (Tol) (80mL) was added and stirred evenly, and heated to 120°C for 48 hours of condensation and reflux reaction. After the system was cooled, toluene was spun out by rotary evaporator; dichloromethane was added for extraction, and the organic layer was washed with pure water, and then the solvent was removed by reduced pressure distillation and rotary evaporation, and separated by silica gel chromatography column, and the eluent was DCM: PE = 1: 3, and the white powder product Y2Cl-EDOT was purified.

[0071] (2) Electrochemical synthesis of P(Y2Cl-EDOT) conjugated polymer

[0072]

[0073] Electrochemical polymerization was carried out in a three-electrode system, with a silver / silver chloride electrode as a reference electrode, a platinum wire as a counter electrode, and an ITO glass as a working electrode; 10 mL of dichloromethane was used as the solvent, Y2Cl-EDOT (0.0043 g, 0.01 mmol) was used as the polymerization monomer, and tetrabutylammonium hexafluorophosphate (0.3874 g, 1 mmol) was used as the supporting electrolyte; the polymerization was carried out using a constant potential method, with a polymerization potential of 0.93 V, a scan rate of 100 mV / s, and a polymerization time of 120 s. The polymer film obtained by electrodeposition was soaked and rinsed with acetonitrile to remove the electrolyte and precursor in the polymer. The obtained polymer film was placed in MeCN-Bu4NPF6 (0.1 mol·L -1 ) system for spectroelectrochemical characterization.

[0074] (3) Study on electrochromic properties (i) Combination Figure 1 , observe the color change of the polymer material with the naked eye. It can be seen that with the increase of potential, the color of the polymer material changes from brown to blue. This is because the neutral polymer material has an absorption peak in the purple light region and the red light region, and the color of the neutral polymer material is brown; after the polymer material is oxidized, the absorption peak in the purple light region gradually weakens, and the absorption peak in the red light region gradually weakens, and finally disappears completely; therefore, the polymer material in the completely dedoped state appears brown, and the doped polymer material appears blue.

[0075] (ii) The response time and coloring efficiency calculated from the time-transmittance curve are shown in Table 1.

[0076] Table 1 Electrochromic parameters of P(Y2Cl-EDOT)

[0077]

[0078] The present invention studies the optical transmittance of P(Y2Cl-EDOT) at wavelengths of 537nm, 890nm and 1100nm by the timed absorption method. During the experiment, the sawtooth wave periodic change time of the potential and time is 5s. Figure 2 As shown. Under the three wavelengths, the polymer material exhibits a certain optical contrast and good optical stability; in addition, the optical transmittance has a great influence on the color change of the polymer material, and the polymer material can be transformed from brown in a completely dedoped state to dark blue in a doped state.

[0079] Example 2

[0080] (1) Synthesis of T2Cl-EDOT active precursor

[0081]

[0082] Under nitrogen atmosphere, 1,4-dibromo-2,3-dichlorobenzene (1.64mmol, 0.5g), tributyl (2,3-dihydro [3,4-b] [1,4] dioxin-5-yl) stannane (4.1mmol, 1.772g), and catalyst Pd (PPh3) 2Cl2 (0.076mmol, 0.066g) were placed in a 250mL single-necked flask, and dry toluene (80mL) was added and stirred evenly, and heated to 120°C for condensation and reflux reaction for 48 hours. After the system was cooled, toluene was spun out by rotary evaporator; dichloromethane was added for extraction, and the organic layer was washed with pure water, and then the solvent was removed by reduced pressure distillation and rotary evaporation, and separated by silica gel chromatography column, and the eluent was DCM: PE = 1: 3, and the white powder product T2Cl-EDOT was purified.

[0083] (2) Electrochemical synthesis of P(T2Cl-EDOT) conjugated polymer

[0084]

[0085] Electrochemical polymerization was carried out in a three-electrode system, with a silver / silver chloride electrode as a reference electrode, a platinum wire as a counter electrode, and a glassy carbon as a working electrode; 10 mL of dichloromethane was used as the electrolyte, T2Cl-EDOT (0.0043 g, 0.01 mmol) was used as the polymerization monomer, and tetrabutylammonium hexafluorophosphate (0.3874 g, 1 mmol) was used as the supporting electrolyte; the polymerization was carried out using a constant potential method, with a polymerization potential of 0.9 V, a scan rate of 100 mV / s, and a polymerization time of 120 s. The polymer film obtained by electrodeposition was soaked and rinsed with acetonitrile to remove the electrolyte and precursor in the polymer. The obtained polymer film was placed in MeCN-Bu4NPF6 (0.1 mol·L -1 ) system for spectroelectrochemical characterization.

[0086] (3) Study on electrochromic properties (i) Combination Figure 3 , observe the color change of the polymer material with the naked eye. It can be seen that with the increase of potential, the color of the polymer material changes from cyan to blue. This is because the neutral polymer material has an absorption peak in the purple light region and the red light region, and the color of the neutral polymer material is blue; after the polymer material is oxidized, the absorption peak in the purple light region gradually weakens, and the absorption peak in the red light region gradually weakens, and finally disappears completely; therefore, the polymer material in the completely dedoped state appears cyan, and the doped polymer material appears blue.

[0087] (ii) The response time and coloring efficiency calculated from the time-transmittance curve are shown in Table 2.

[0088] Table 2 Electrochromic parameters of P(T2Cl-EDOT)

[0089]

[0090] The optical transmittance of P(T2Cl-EDOT) was studied by timed absorption method at wavelengths of 465nm, 730nm and 1100nm. During the experiment, the time interval of the potential step change was 5s. Figure 4 As shown. At three wavelengths, the polymer material exhibits a certain optical contrast and good optical stability; in addition, the optical transmittance has a great influence on the color change of the polymer material, and the polymer material can be transformed from cyan in a completely dedoped state to blue in a doped state.

[0091] Example 3

[0092] (1) Synthesis of Cl-EDOT active precursor

[0093]

[0094] Under nitrogen atmosphere, 2,5-dibromo-chlorobenzene (1.85mmol, 0.50g), 2-tinbutyl-3-methylthiophene (4.64mmol, 2.0g), and catalyst Pd(PPh3)2Cl2 (0.074mmol, 0.086g) were placed in a 250mL single-necked flask, and dry toluene (80mL) was added and stirred evenly, and heated to 120°C for condensation and reflux reaction for 48 hours. After the system was cooled, toluene was spun out by rotary evaporator; dichloromethane was added for extraction, and then pure water was added to wash the organic layer, and then the solvent was removed by reduced pressure distillation and rotary evaporation, and separated by silica gel chromatography column, and the eluent was DCM:PE=1:3, and the white powder product Cl-EDOT was purified.

[0095] (2) Electrochemical synthesis of P(Cl-EDOT) polymer

[0096]

[0097] Electrochemical polymerization was carried out in a three-electrode system, with a silver / silver chloride electrode as a reference electrode, a platinum wire as a counter electrode, and a glassy carbon as a working electrode; 10 mL of dichloromethane was used as the electrolyte, Cl-EDOT (0.0039 g, 0.01 mmol) was used as the polymerization monomer, and tetrabutylammonium hexafluorophosphate (0.3874 g, 1 mmol) was used as the supporting electrolyte; the polymerization was carried out using a constant potential method, with a polymerization potential of 1.05 V, a scan rate of 100 mV / s, and a polymerization time of 120 s. The polymer film obtained by electrodeposition was soaked and rinsed with acetonitrile to remove the electrolyte and precursor in the polymer. The obtained polymer film was placed in MeCN-Bu4NPF6 (0.1 mol·L -1 ) system for spectroelectrochemical characterization.

[0098] (3) Study on electrochromic properties (iii) Combined Figure 5 , observe the color change of the polymer material with the naked eye. It can be seen that with the increase of potential, the color of the polymer material changes from yellow to blue. This is because the neutral polymer material has an absorption peak in the purple light region and the red light region, and the color of the neutral polymer material is yellow; after the polymer material is oxidized, the absorption peak in the purple light region gradually weakens, and the absorption peak in the red light region gradually weakens, and finally disappears completely; therefore, the polymer material in the completely dedoped state appears yellow, and the doped polymer material appears blue.

[0099] (iv) The response time and coloring efficiency calculated from the time-transmittance curve are shown in Table 3.

[0100] Table 3 Electrochromic parameters of P(Cl-EDOT)

[0101]

[0102] The optical transmittance of P(Cl-EDOT) was studied by timed absorption method at wavelengths of 465nm, 690nm and 1100nm. During the experiment, the time interval of the potential step change was 5s. Figure 6 As shown. At three wavelengths, the polymer material exhibits a certain optical contrast and good optical stability; in addition, the optical transmittance has a great influence on the color change of the polymer material, and the polymer material can be transformed from cyan in a completely dedoped state to blue in a doped state.

[0103] The absorption position of the polymer determines the color of the polymer, which is of great significance for the preparation of electrochromic polymers of various colors. The response time is also an important parameter of the electrochromic material, which reveals the speed at which the doped ions enter the polymer main chain during the doping process. It can be seen from Tables 1, 2 and 3 that the conjugated polymer prepared by the present invention has a fast response time and a high coloring efficiency when used for electrochromism.

[0104] In summary, the conjugated polymer of the present invention, as an electrochromic material, can be observed to have a stable and reversible color change of yellow or dark blue under the action of an applied voltage. It also has good electrochromic properties, including fast response time, high coloring efficiency and good optical transmittance, and can be widely used in electrochromic devices or products.

[0105] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A conjugated polymer, It is characterized in that It has any of the following molecular structures:

2. The method for preparing the conjugated polymer according to claim 1, It is characterized in that The conjugated polymer is prepared from an active precursor by an electrochemical polymerization method; the active precursor has any one of the following structural formulas:

3. The preparation method according to claim 2, It is characterized in that The preparation method of the active precursor comprises: under the protection of an inert gas, subjecting the intermediate compound to a stannic compound of EDOT in a catalyst and a solvent for a Stille / Suzuki cross-coupling reaction, thereby obtaining the active precursor; The intermediate compound is: 1,4-dibromo-2,5-dichlorobenzene, 1,4-dibromo-2,3-dichlorotoluene or 1,4-dibromo-2-chlorobenzene.

4. The preparation method according to claim 3, It is characterized in that The inert gas is argon; And / or, the tin hydrocarbon compound of EDOT is 5-tributyltin-3,4-vinyldioxythiophene; And / or, the catalyst is at least one of tetrakistriphenylphosphine palladium or bistriphenylphosphine palladium dichloride; And / or, the solvent includes at least one of toluene and N,N-dimethylformamide.

5. The preparation method according to claim 3, It is characterized in that The molar ratio of the intermediate compound, the EDOT tin hydrocarbon compound and the catalyst is 1:2-3:0.03-0.1; And / or, the reaction temperature is 100°C to 120°C; And / or, the reaction time is 24h to 48h.

6. The preparation method according to claim 2, It is characterized in that The electrochemical polymerization method comprises using a solution containing the active precursor as an electrolyte solution, and adopting a constant potential method, a constant current method or a cyclic voltammetry method to electrodeposit the conjugated polymer thin film material; And or, the electrochemical polymerization method is carried out in a three-electrode system consisting of a reference electrode, a counter electrode and a working electrode; the working electrode comprises a glassy carbon electrode / ITO conductive glass, the counter electrode comprises a platinum wire, and the reference electrode comprises an Ag / AgCl electrode.

7. The preparation method according to claim 6, It is characterized in that The electrolyte solution further comprises a solvent; the solvent comprises at least one of dichloromethane, chloroform or acetonitrile; And / or, the electrolyte solution further contains a supporting electrolyte; the supporting electrolyte comprises at least one of tetrabutylammonium hexafluorophosphate, tetrabutylammonium tetrafluoroborate or lithium perchlorate; And / or, the concentration of the active precursor in the electrolyte solution is 0.001 to 0.01 mol·L -1 ; and or, the concentration of the supporting electrolyte in the electrolyte solution is 0.05 to 0.15 mol·L -1 .

8. The preparation method according to claim 6, It is characterized in that The electrochemical polymerization method adopts a constant potential method to carry out electrodeposition; The potential of the electrodeposition is 0.8V to 1.2V; and / or the time of the electrodeposition is 80s to 200s.

9. An electrochromic material, It is characterized in that The invention comprises the conjugated polymer according to claim 1 or the conjugated polymer prepared by the preparation method according to any one of claims 2 to 8.

10. Use of the conjugated polymer according to claim 1 or the conjugated polymer prepared by the preparation method according to any one of claims 2 to 8 in an electrochromic device.

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