Monomers, polymers, methods for their preparation and use in electrochromic materials

Abstract

The application discloses a monomer, a polymer, a preparation method of the monomer and the polymer and application of the monomer and the polymer in electrochromic materials, and relates to the technical field of electrochromic materials. 18 The monomer has the following structural formula: wherein R is selected from alkyl, aryl or substituted aryl with carbon atom number C1-C 18 ; D is selected from thiophene or 3,4-ethylenedioxythiophene; and pi is selected from any one of the following structures: The monomer is an electrochromic monomer with low driving voltage, high contrast, fast switching time and good stability.

Description

Technical Field

[0001] This invention relates to the field of electrochromic materials technology, and in particular to a monomer, a polymer, a method for preparing the same, and their application in electrochromic materials. Background Technology

[0002] Electrochromism (EC) refers to the phenomenon where a material's color, absorbance, and transmittance undergo reversible changes under the influence of an electric field. Materials exhibiting electrochromic properties are widely used in smart windows, electronic displays, wearable devices, and other fields, becoming a research hotspot in optoelectronics, materials science, and intelligent technologies in recent years. Electrochromic materials can rapidly change color under voltage-driven conditions and maintain good stability during repeated operations. This characteristic provides a theoretical basis and technical support for various applications such as intelligent dimming, reflective optics, and intelligent visual displays.

[0003] With the continuous development of green buildings, energy conservation, and intelligent systems, research on electrochromic materials is gradually progressing towards high efficiency, low energy consumption, and multifunctionality. Among them, electrochromic conjugated polymers, as a class of materials with significant photoelectric properties, have attracted widespread attention due to their excellent electrochromic characteristics. Compared with traditional metal oxide or inorganic semiconductor electrochromic materials, conjugated polymers have a broader absorption spectrum, covering the absorption range from ultraviolet and visible light to infrared light, and also have higher optical contrast and faster color switching speed. Therefore, they show broad prospects in various application fields such as smart windows, solar reflectors, anti-glare mirrors, smart displays, and wearable devices.

[0004] The working principle of electrochromic conjugated polymers involves a redox process. Essentially, it involves controlling the oxidized or reduced state of the polymer through voltage, causing changes in the electron cloud within the polymer backbone, thereby altering its optical properties. When a voltage is applied, the electrochromic conjugated polymer undergoes electron injection or removal, processes known as p-doping (oxidation) and n-doping (reduction), respectively. By removing or injecting electrons, charge carriers such as polarons and bipolarons in the polymer molecular chain are excited or eliminated, ultimately leading to changes in the polymer's color and light transmittance.

[0005] However, despite the significant electrochromic effect of electrochromic conjugated polymers, their performance in practical applications still faces several challenges. First, the driving voltage for electrochromic conjugated polymers is relatively high, typically requiring tens of volts or even higher to achieve color change. This can lead to additional energy consumption in certain applications, reducing the overall efficiency of the intelligent system. Second, the optical contrast of these materials still cannot compare with that of inorganic electrochromic materials. Although their broad absorption spectral range allows them to exhibit better contrast in certain specific wavelengths, their overall performance still needs to be improved to meet more stringent requirements in practical applications.

[0006] Furthermore, the switching speed and stability of electrochromic conjugated polymers are also pressing issues that need to be addressed. Although some new conjugated polymers have improved switching speeds, they still suffer from long reaction times and slow response times, which limit their application in fast-switching smart displays and dimming systems. In long-term use, electrochromic conjugated polymers may degrade due to repeated redox processes, leading to a gradual decline in their performance, which is also one of the main bottlenecks in their current applications.

[0007] Furthermore, the poor solubility of conjugated polymers often affects their subsequent processing and applications. Many traditional conjugated polymers tend to aggregate into large molecules due to the strong interactions between polymer chains, resulting in poor solubility and making them difficult to process further or form thin films, which limits their application in large-scale production.

[0008] Therefore, there is an urgent need to provide an electrochromic polymer with low driving voltage, high contrast, fast switching time, and good stability. Summary of the Invention

[0009] The purpose of this invention is to provide an electrochromic polymer monomer and polymer with low driving voltage, high contrast, fast switching time, and good stability.

[0010] The first aspect of the present invention is:

[0011] Provide a monomer.

[0012] The second aspect of the present invention is:

[0013] A method for preparing a monomer is provided.

[0014] The third aspect of the present invention is:

[0015] A polymer is provided.

[0016] The present invention also proposes a method for preparing a polymer.

[0017] The present invention also proposes an electrochromic material.

[0018] The present invention also proposes an electrochromic device.

[0019] Specifically, the technical solution adopted according to the first aspect of the present invention is as follows:

[0020] A monomer, specifically with the following structural formula:

[0021]

[0022] Wherein, R is selected from alkyl, aryl or substituted aryl groups having C1-C18 carbon atoms;

[0023] D is selected from thiophene or 3,4-ethylenedioxythiophene;

[0024] π is selected from any of the following structures:

[0025]

[0026] According to embodiments of the present invention, one of the technical solutions has at least one of the following advantages or beneficial effects:

[0027] The monomer of the present invention uses benzodithiophene-4,8-dione with good planarity as the acceptor, thiophene or 3,4-ethylenedioxythiophene and their duplexes as the π-bridge, and thiophene derivatives as the donor. Through the selection of groups, a unique D-π-A-π-D structure is formed, thereby making the monomer an electrochromic monomer with low driving voltage, high contrast, fast switching time and good stability.

[0028] The monomer of the present invention, after being prepared into a polymer, exhibits a transmittance change of 1.2-5.9% in the neutral state and 3.1-6.2% in the doped state, indicating that the polymer has a good short-term memory effect. Since short-term memory is used to measure the stability of a polymer when a voltage is applied for a short time, the polymer based on the monomer of the present invention has excellent stability.

[0029] Furthermore, the monomers of the present invention, after being prepared into polymers, exhibit good optical contrast, high coloring efficiency, and excellent optical stability, achieving an optical contrast of 33.24-50.93% in different wavelength ranges.

[0030] According to one embodiment of the present invention, in the monomer structure of the present invention, 3,4-ethylenedioxythiophene, as a strong electron-donating group, can reduce the initial oxidation potential of the monomer, decrease the optical band gap of the conjugated polymer, and improve the electrochromic properties. Benzodithiophene-4,8-dione has a strong electron-withdrawing ability, which can enhance the intramolecular charge transfer of the DAD conjugated polymer.

[0031] According to one embodiment of the present invention, R is selected from alkyl, aryl and / or substituted aryl groups having a carbon number of C4-C15.

[0032] According to one embodiment of the present invention, the substituted aryl group includes aryl groups substituted with halogen, nitro, amino, hydroxyl or carboxyl groups.

[0033] According to one embodiment of the present invention, D is thiophene, and π is selected from structures containing thiophene, from structure I to structure VI. In the monomer structure of the present invention, the thiophene group is more advantageous than the 3,4-ethylenedioxythiophene group in improving the coloring efficiency of the polymer prepared from the monomer.

[0034] According to one embodiment of the present invention, when both π and D are thiophene groups, the number of thiophene groups is less than 6, which is more conducive to improving the coloring efficiency of the polymer prepared from this monomer. Preferably, when both π and D are thiophene groups, the coloring efficiency is optimal when the number of thiophene groups is 4.

[0035] According to one embodiment of the present invention, the π is selected from one of structure I, structure II, and structure IV. In the monomer structure of the present invention, excessive elongation of the conjugated structure has an adverse effect on the coloring efficiency of the polymer prepared from the monomer. For example, when D is 3,4-ethylenedioxythiophene, the coloring efficiency is worse when π is selected from structure V than when selected from structure IV.

[0036] Preferably, in the monomer structure of the present invention, when both D and π are thiophene groups, the combination of four thiophene groups is more conducive to improving the coloring efficiency. The polymer prepared with this monomer can achieve a coloring efficiency of 570.84 cm² C. -1 Compared to existing polymers (with a coloring efficiency of 92.19%), this is superior. cm 2 C-1 Compared to [previous year], this represents an increase of 519.58%.

[0037] Specifically, the technical solution adopted according to the second aspect of the present invention is as follows:

[0038] A method for preparing the monomer includes the following steps:

[0039] Under a protective gas atmosphere, compound A, a catalyst, and tributyl(2,3-dihydro[3,4-b][1,4]dioxin-5-yl)tinane or tributyl(2-thienyl)tin are mixed in a solvent and reacted to obtain the monomer.

[0040] The structural formula of compound A is:

[0041]

[0042] Where X is a halogen group.

[0043] The role of tributyl(2,3-dihydro[3,4-b][1,4]dioxin-5-yl)stanane or tributyl(2-thienyl)tin is to connect the EDOT group in compound a and the thiophene group in tributyl(2,3-dihydro[3,4-b][1,4]dioxin-5-yl)stanane or tributyl(2-thienyl)tin as a donor to generate the monomer with low driving voltage, high contrast, fast switching time and good stability.

[0044] According to one embodiment of the present invention, the mass ratio of compound A to tributyl(2,3-dihydro[3,4-b][1,4]dioxin-5-yl)tinane is 0.1-0.12:0.1-0.5.

[0045] According to one embodiment of the present invention, the mass ratio of compound A to the catalyst is 0.1-0.12:0.003-0.00625.

[0046] According to one embodiment of the present invention, the catalyst comprises a palladium catalyst and dimethylformamide.

[0047] The use of a palladium catalyst ensures that compound A reacts with the tributyl(2,3-dihydro[3,4-b][1,4]dioxin-5-yl)tinane.

[0048] The use of dimethylformamide can serve as a catalyst to improve reaction efficiency and product purity.

[0049] According to one embodiment of the present invention, the solvent includes at least one selected from N,N-dimethylformamide, toluene, benzene, acetone, and ethanol.

[0050] According to one embodiment of the present invention, the protective gas includes at least one of nitrogen or rare gases.

[0051] According to one embodiment of the present invention, the reaction is carried out at a temperature of 70-130°C. Preferably, the reaction temperature is 90-120°C.

[0052] According to one embodiment of the present invention, the reaction takes 8-24 hours. Preferably, the reaction takes 12-24 hours.

[0053] According to one embodiment of the present invention, the reaction is a Stille coupling reaction.

[0054] According to one embodiment of the present invention, after the Stille coupling reaction is completed, a washing step is further included.

[0055] According to one embodiment of the present invention, the reagent used for washing includes a sodium chloride solution.

[0056] According to one embodiment of the present invention, after washing, a step of chromatographic separation and purification is further included.

[0057] According to one embodiment of the present invention, the separation column used for chromatographic separation and purification is a silica gel column.

[0058] In another aspect, the present invention also provides a polymer. The polymer's raw materials include the monomers described in the first aspect of the embodiments above. Since this application utilizes all the technical solutions described above for the monomers, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments.

[0059] According to one embodiment of the present invention, the polymer has the structural formula shown in formula (III):

[0060]

[0061] Where n is greater than 0;

[0062] In the polymer structural formula, the selection of R, π, and D is consistent with that of R, π, and D in the monomer.

[0063] According to embodiments of the present invention, one of the technical solutions has at least one of the following advantages or beneficial effects:

[0064] The polymer of this invention has excellent electrochromic properties, enabling reversible color switching at low driving voltages. Under applied voltage, stable and reversible color changes from deep blue to blue-gray or from blue-black to gray can be observed. It also exhibits excellent electrochromic properties such as high contrast, high coloring efficiency, and fast switching time, and has significant application prospects in the commercial electrochromic field.

[0065] Furthermore, in the structure of the polymer of the present invention, benzodithiophene-4,8-dione has good planarity and strong electron-withdrawing ability, resulting in a high degree of conjugation of the polymer and good quality of the film formed by the polymer, thereby further promoting the high contrast, fast switching time and good stability of the polymer.

[0066] According to one embodiment of the present invention, n represents the average degree of polymerization, and n is 10-5000.

[0067] According to one embodiment of the present invention, n is 10-3000.

[0068] According to one embodiment of the present invention, the method for preparing the polymer includes the following steps: mixing an electrolyte and the monomer in a solvent to obtain an electrolyte solution, adding the electrolyte solution to an electrode system, and depositing the polymer through an electrochemical polymerization reaction.

[0069] According to one embodiment of the present invention, the electrolyte includes at least one of tetrabutylammonium hexafluorophosphate, tetrabutylammonium tetrafluoroborate, and lithium perchlorate.

[0070] According to one embodiment of the present invention, adding the electrolyte to the electrode system includes the following steps: adding the electrolyte to an electrolytic cell of a three-electrode system.

[0071] According to one embodiment of the present invention, the electrochemical polymerization reaction includes carrying out the electrochemical polymerization reaction on the working electrode of a three-electrode system using a constant potential method.

[0072] According to one embodiment of the present invention, the electrochemical polymerization reaction has a polymerization potential of 0.3-1.05V and a polymerization time of 30-80s.

[0073] According to one embodiment of the present invention, the electrochemical polymerization reaction has a polymerization potential of 0.3V, 0.45V, 0.5V, 0.65V, 0.7V, 0.85V, 0.95V or 1.05V.

[0074] According to one embodiment of the present invention, the electrochemical polymerization reaction is carried out over a time of 30s, 40s, 45s, 50s, 55s, 60s, or 80s.

[0075] According to one embodiment of the present invention, the electrochemical polymerization reaction has a polymerization potential of 0.95V and a polymerization time of 50s.

[0076] According to one embodiment of the present invention, the electrochemical polymerization reaction has a polymerization potential of 0.45V and a polymerization time of 45s.

[0077] According to one embodiment of the present invention, the electrochemical polymerization reaction has a polymerization potential of 1.05V and a polymerization time of 60s.

[0078] According to one embodiment of the present invention, the electrochemical polymerization reaction has a polymerization potential of 0.65V and a polymerization time of 60s.

[0079] According to one embodiment of the present invention, the electrochemical polymerization reaction has a polymerization potential of 0.3V and a polymerization time of 30s.

[0080] According to one embodiment of the present invention, the electrochemical polymerization reaction has a polymerization potential of 0.5V and a polymerization time of 40s.

[0081] According to one embodiment of the present invention, the electrochemical polymerization reaction has a polymerization potential of 0.7V and a polymerization time of 80s.

[0082] According to one embodiment of the present invention, 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.

[0083] According to one embodiment of the present invention, the constant potential method includes the constant current method or the cyclic voltammetry method.

[0084] According to one embodiment of the present invention, the solvent in the electrolyte includes at least one of dichloromethane (CH2Cl2), trichloromethane (CHCl3), or acetonitrile (MeCN).

[0085] According to one embodiment of the present invention, the concentration of the monomer in the electrolyte is 1-12 mmol·L⁻¹. -1 Preferably, the monomer concentration is 1-10 mmol / L. -1 .

[0086] According to one embodiment of the present invention, the concentration of the electrolyte in the electrolyte solution is 0.05-0.3 mol·L⁻¹. -1 Preferably, the concentration of the electrolyte is 0.06-0.1 mol·L⁻¹. -1 .

[0087] According to one embodiment of the present invention, the electrochemical polymerization reaction has the following reaction process:

[0088]

[0089] In another aspect, the present invention provides an electrochromic material comprising the aforementioned polymer.

[0090] In another aspect, the present invention provides an electrochromic device comprising the aforementioned electrochromic material.

[0091] According to one embodiment of the present invention, the electrochromic device includes at least one of a display, electrochromic glass, a smart window, or a rearview mirror.

[0092] According to one embodiment of the present invention, smart windows have significant advantages in energy conservation, emission reduction, and comfort. Through the electrochromic regulation of the polymer described in the present invention, the light transmittance and heat transmittance of the window can be dynamically adjusted, thereby effectively controlling the indoor light intensity and temperature and reducing the energy consumption of air conditioning and lighting systems.

[0093] According to one embodiment of the present invention, the lens used in the rearview mirror is an anti-glare lens. The anti-glare lens can achieve automatic light adjustment through the electrochromic adjustment of the polymer of the present invention, thereby improving visual comfort. It is especially suitable for driver's glasses, camera lenses and other occasions.

[0094] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0095] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0096] Figure 1 The image shows the electrochromic properties of the polymer prepared in Example 1.

[0097] Figure 2 The image shows the electrochromic properties of the polymer prepared in Example 2.

[0098] Figure 3 The image shows the electrochromic properties of the polymer prepared in Example 3.

[0099] Figure 4 The image shows the electrochromic properties of the polymer prepared in Example 4.

[0100] Figure 5 The image shows the electrochromic properties of the polymer prepared in Example 5.

[0101] Figure 6 The image shows the electrochromic properties of the polymer prepared in Example 6.

[0102] Figure 7 The image shows the electrochromic properties of the polymer prepared in Example 7.

[0103] Figure 8 The image shows the electrochromic properties of the polymer prepared in Example 8.

[0104] Figure 9 The image shows the electrochromic properties of the polymer prepared for comparison. Detailed Implementation

[0105] The terms "preferred," "more preferably," etc., 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.

[0106] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0107] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of the present invention.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] Coloring efficiency is a quantitative analysis of the amount of charge flowing through the polymer when a material undergoes color changes and transmittance alterations under an applied voltage. In other words, it reflects the energy loss during material application. Higher coloring efficiency indicates better energy utilization and greater energy savings. Coloring efficiency, or CE value, is calculated as the ratio of the change in optical density (ΔOD) during doping and dedoping to the amount of charge (Qd) flowing through the material's potential area. The formula is as follows:

[0112] CE = ΔOD / Qd;

[0113] Where ΔOD is the logarithm of the ratio of transmittance in different states of the material at a specified wavelength, and the calculation formula is as follows:

[0114] ΔOD = log(Tox / Tred);

[0115] Tox and Tred are the transmittance values ​​of the material in its oxidized and reduced states, respectively.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] The polymers were obtained by electropolymerization at different constant voltage potentials using ETBD, EEBD, TTBD, TEBD, EEEBD, TTTBD, TEEBD, and ETTBD as monomers. The benzodithiophene-4,8-dione polymer films exhibit excellent electrochromic properties, achieving reversible color switching and high contrast changes at low driving voltages, and show significant application potential in the commercial electrochromic field.

[0120] In the examples and comparative examples, TOL is toluene and DMF is dimethylformamide.

[0121] Example 1

[0122] A monomer (denoted as ETBD) has the following structural formula:

[0123]

[0124] The method for preparing the above monomer includes the following steps:

[0125]

[0126] Specifically:

[0127] Under a nitrogen atmosphere, 1,3-bis(5-bromothiophen-2-yl)-5,7-bis(2-ethylhexyl)-4H,8H-benzo[1,2-c:4,5-c']dithiophene-4,8-dione (0.08 g, 0.105 mmol), tributyl(2,3-dihydro[3,4-b][1,4]dioxin-5-yl)stanane (0.114 g, 0.263 mmol), and catalyst Pd(PPh3)4 (0.005 g, 0.0042 mmol) were placed in a 250 mL single-necked flask, and TOL (32 mL) and DMF (8 mL) were added and stirred until homogeneous. The mixture was heated to 120 °C and refluxed for 48 hours. After cooling, the product was obtained.

[0128] The obtained product was poured into saturated brine and extracted five times with dichloromethane. The organic layer was then washed with water. The solvent was removed by vacuum distillation and rotary evaporation. Separation was performed using a silica gel column with dichloromethane and petroleum ether mixed in a volume ratio of 1:3 as the eluent. The purified product was 35.4 mg of brownish-red lumpy product (monomer), with a yield of 37.9%.

[0129] The 1H NMR characterization results of the product (monomer) are as follows: 1H NMR(400MHz,Chloroform-d)δ7.71(d,J=4.1Hz,2H),7.16(s,2H),6.23(s,2H),4.26(d,J=46.6Hz,8H),3 .30(dd,J=15.5,6.8Hz,2H),3.22(d,J=6.5Hz,2H),1.71(s,2H),1.36–1.14(m,19H),0.93–0.73(m,13H).

[0130] A polymer (denoted as P(ETBD)) has the following structural formula:

[0131]

[0132] The preparation of the above polymer includes the following steps:

[0133]

[0134] Specifically:

[0135] The polymer was prepared by electrochemical polymerization, which 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 6 mol / L HCl solution to generate an AgCl coating on the surface).

[0136] Using 10 mL of dichloromethane as the electrolyte, ETBD (0.01 mol / L) as the monomer for polymerization, and tetrabutylphosphine hexafluoride (0.1 mol / L) as the supporting electrolyte, polymerization was carried out using a potentiostatic method with a polymerization potential of 0.95 V and a polymerization time of 50 s. The polymer film obtained by electrodeposition was rinsed with acetonitrile to remove the electrolyte solution and oligomers generated in the polymer.

[0137] Example 2

[0138] A monomer (denoted as EEBD) has the following structural formula:

[0139]

[0140] The method for preparing the above monomer includes the following steps:

[0141]

[0142] Specifically:

[0143] Under a nitrogen atmosphere, 1,3-bis(7-bromo-2,3-dihydrothiopheno[3,4-b][1,4]dioxin-5-yl)-5,7-bis(2-ethylhexyl)-4H,8Hbenzo[1,2-c:4,5-c'-]dithiophene-4,8-dione (0.238 g, 0.27 mmol / L) and tributyl(2,3-dihydro[3,4-b][1,4]dioxin-5-yl) were added to the atmosphere. 0.28 g of stanane and 0.03 g of catalyst Pd(PPh3)4 (0.027 mmol) were placed in a 250 mL single-necked flask. Toluene (32 mL) and DMF (N,N-dimethylacetamide, 8 mL, with a volume ratio of 4:1) were added and stirred until homogeneous. The mixture was heated to 120 °C and refluxed for 48 hours. After cooling, the product was obtained.

[0144] The product was poured into saturated brine and extracted four times with dichloromethane. The organic layer was then washed with water. The solvent was removed by vacuum distillation and rotary evaporation. Separation was performed using a silica gel column with dichloromethane and petroleum ether mixed in a volume ratio of 1:5 as the eluent. The purified product (monomer) was 73.5 mg red powder, with a yield of 27%.

[0145] The 1H NMR characterization results of the product (monomer) are as follows: 1 H NMR(400MHz,Chloroform-d)δ6.27(s,2H),4.25(dd,J=49.1,4.5Hz,16H),3.37 –3.09(m,4H),1.73(s,2H),1.41–1.09(m,19H),0.83(dt,J=26.7,7.2Hz,13H).

[0146] A polymer (denoted as P(EEBD)) has the following structural formula:

[0147]

[0148] The preparation of the above polymer includes the following steps:

[0149]

[0150] Specifically:

[0151] The polymer was prepared by electrochemical polymerization, which 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 6 mol / L HCl solution to generate an AgCl coating on the surface).

[0152] Using 10 mL dichloromethane as the electrolyte, EEBD (0.01 mol / L) as the monomer, and tetrabutylphosphine hexafluoride (0.1 mol / L) as the supporting electrolyte, electrochemical polymerization was carried out using a potentiostatic method. The polymerization potential was 0.45 V, and the polymerization time was 45 s. The polymer P (EEBD) film electrodeposited on the ITO conductive glass surface was rinsed with acetonitrile to remove the electrolyte solution and oligomers generated in the polymer.

[0153] Example 3

[0154] A monomer (denoted as TTBD) has the following structural formula:

[0155]

[0156] The method for preparing the above monomer includes the following steps:

[0157]

[0158] Specifically:

[0159] Under a nitrogen atmosphere, 1,3-bis(5-bromothiophen-2-yl)-5,7-bis(2-ethylhexyl)-4H,8H-benzo[1,2-c:4,5-c']dithiophene-4,8-dione (0.31 g, 0.416 mmol), tributyl(thiophen-2-yl)stanane (0.372 g, 0.998 mmol), and catalyst Pd(PPh3)4 (0.048 g, 0.042 mmol) were placed in a 250 mL single-necked flask. TOL (toluene, 32 mL) and DMF (N,N-dimethylacetamide, 8 mL, TOL to DMF volume ratio 4:1) were added and stirred until homogeneous. The mixture was heated to 120 °C and refluxed for 48 hours. After cooling, the product was obtained.

[0160] The product was poured into saturated brine and extracted four times with dichloromethane. The organic layer was then washed with water. The solvent was removed by vacuum distillation and rotary evaporation. Separation was performed using a silica gel column with dichloromethane and petroleum ether mixed in a volume ratio of 1:5 as the eluent. The purified product (monomer) was 24.9 mg red powder, with a yield of 77.4%.

[0161] The 1H NMR characterization results of the product (monomer) are as follows: 1H NMR(400MHz,Chloroform-d)δ7.63(d,J=4.0Hz,2H),7.22(dd,J=8.4,4.3Hz,4H),7.11(d,J=3.9Hz,2H),7.0 3–6.95(m,2H),3.26(d,J=7.0Hz,4H),1.76–1.66(m,2H),1.40–1.16(m,17H),0.84(dt,J=21.3,7.2Hz,12H).

[0162] A polymer (denoted as P(TTBD)) has the following structural formula:

[0163]

[0164] The preparation of the above polymer includes the following steps:

[0165]

[0166] Specifically:

[0167] 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 in 6 mol / L HCl solution for 100s to generate an AgCl coating on the surface).

[0168] Using 10 mL of dichloromethane as the electrolyte, TTBD (0.01 mol / L) as the monomer, and tetrabutylphosphine hexafluoride (0.1 mol / L) as the supporting electrolyte, electrochemical polymerization was carried out using a potentiostatic method. The polymerization potential was 1.05 V, and the polymerization time was 60 s. The polymer P (TTBD) film electrodeposited on the ITO conductive glass surface was rinsed with acetonitrile to remove the electrolyte solution and oligomers generated in the polymer.

[0169] Example 4

[0170] A monomer (denoted as TEBD) has the following structural formula:

[0171]

[0172] The method for preparing the above monomer includes the following steps:

[0173]

[0174] Specifically:

[0175] Under a nitrogen atmosphere, 1,3-bis(7-bromo-2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-5,7-bis(2-ethylhexyl)-4H,8Hbenzo[1,2-c:4,5-c'-]dithiophene-4,8-dione (0.068 g, 0.077 mmol), tributyl(thieno-2-yl)stanane (0.069 g, 0.185 mmol), and catalyst Pd(PPh3)4 (0.07 g, g excess) were placed in a 250 mL single-necked flask, and TOL (32 mL) and DMF (8 mL) were added and stirred until homogeneous. The mixture was heated to 120 °C and refluxed for 48 hours. After cooling, the product was obtained.

[0176] The obtained product was poured into saturated brine and extracted five times with dichloromethane. The organic layer was then washed with water. The solvent was removed by vacuum distillation and rotary evaporation. Separation was performed using a silica gel column with dichloromethane and petroleum ether mixed in a volume ratio of 1:5 as the eluent. The purified product was 37.4 mg of red-black powder (monomer), with a yield of 54.6%.

[0177] A polymer (denoted as P(TEBD)) has the following structural formula:

[0178]

[0179] The preparation of the above polymer includes the following steps:

[0180]

[0181] Specifically:

[0182] The above polymer was prepared by electrochemical polymerization, which 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 6 mol / L HCl solution to generate an AgCl coating on the surface).

[0183] Using 10 mL of dichloromethane as the electrolyte, TEBD (0.01 mol / L) as the polymerization 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 0.65 V and a polymerization time of 60 s. The polymer film obtained by electrodeposition was rinsed with acetonitrile to remove the electrolyte solution and oligomers generated in the polymer.

[0184] Example 5

[0185] A monomer (denoted as EEEBD) has the following structural formula:

[0186]

[0187] The method for preparing the above monomer includes the following steps:

[0188]

[0189] Specifically:

[0190] Under a nitrogen atmosphere, 1,3-bis(7'-bromo-2,2',3,3'-tetrahydro-[5,5'-bithiophene[3,4-b][1,4]dioxin]-7-yl)-5,7-bis(2-ethylhexyl)-4H,8Hbenzo[1,2-c:4,5-c'-]dithiophene-4,8-dione (0.156 g, 0.134 mmol), tributyl(2,3-dihydro[3,4-b][1,4]dioxin-5-yl)stanane (0.139 g, 0.322 mmol), and catalyst Pd(PPh3)4 (0.07 g, excess) were refluxed for 48 hours. After cooling, the product was obtained.

[0191] The obtained product was poured into saturated brine and extracted five times with dichloromethane. The organic layer was then washed with water. The solvent was removed by vacuum distillation and rotary evaporation. Separation was performed using a silica gel column with dichloromethane and petroleum ether mixed in a volume ratio of 3:1 as the eluent. The purified product (monomer) was 26.4 mg in black powder form, with a yield of 15.3%.

[0192] The 1H NMR characterization results of the product (monomer) are as follows: 1 H NMR(400MHz,Chloroform-d)δ6.25(d,J=17.6Hz,2H),4.26(d,J=57.8Hz,24H),3.33(dd,J=14.9,7.5H z,2H),3.15(dd,J=15.9,6.0Hz,2H),1.74(s,2H),1.41–1.20(m,16H),0.84(dt,J=28.6,7.2Hz,13H).

[0193] A polymer (denoted as P(EEEBD)) has the following structural formula:

[0194]

[0195] The preparation of the above polymer includes the following steps:

[0196]

[0197] Specifically:

[0198] The above polymer was prepared by electrochemical polymerization, which 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 6 mol / L HCl solution to generate an AgCl coating on the surface).

[0199] Using 10 mL of dichloromethane as the electrolyte, monomer (EEEBD) (0.01 mol / L) as the polymerization monomer, and tetrabutylphosphine hexafluoride (0.1 mol / L) as the supporting electrolyte, polymerization was carried out using a constant potential method with a polymerization potential of 0.3 V and a polymerization time of 30 s. The polymer film obtained by electrodeposition was rinsed with acetonitrile to remove the electrolyte solution and oligomers generated in the polymer.

[0200] Example 6

[0201] A monomer (denoted as TTTTBD) has the following structural formula:

[0202]

[0203] The method for preparing the above monomer includes the following steps:

[0204]

[0205] Specifically:

[0206] Under a nitrogen atmosphere, 1,3-bis(5'-bromo-[2,2'-bithiophene]-5-yl)-5,7-bis(2-ethylhexyl)-4H,8H-benzo[1,2-c:4,5-c'-]dithiophene-4,8-dione (0.3 g, 0.322 mmol), tributyl(thiophene-2-yl)stanane (0.289 g, 0.773 mmol), and catalyst Pd(PPh3)4 (0.08 g, excess) were placed in a 250 mL single-necked flask, and TOL (32 mL) and DMF (8 mL) were added and stirred until homogeneous. The mixture was heated to 120 °C and refluxed for 48 hours. After cooling, the product was obtained.

[0207] The obtained product was poured into saturated brine and extracted five times with dichloromethane. The organic layer was then washed with water. The solvent was removed by vacuum distillation and rotary evaporation. Separation was performed using a silica gel column with dichloromethane and petroleum ether mixed in a volume ratio of 1:3 as the eluent. The purified product (monomer) was 239 mg black powder, with a yield of 80.3%.

[0208] The 1H NMR characterization results of the product (monomer) are as follows: 1H NMR (400MHz, Chloroform-d) δ7.63 (s, 2H), 7.18–6.89 (m, 12H), 3.26 (d, J = 7.1Hz, 4H), 1.71 (s, 2H), 1.24 (d, J = 44.3Hz, 18H), 0.85 (d, J = 20.4Hz, 13H).

[0209] A polymer (denoted as P(TTTBD)) has the following structural formula:

[0210]

[0211] The preparation of the above polymer includes the following steps:

[0212]

[0213] Specifically:

[0214] The above polymer was prepared by electrochemical polymerization, which 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 6 mol / L HCl solution to generate an AgCl coating on the surface).

[0215] Using 10 mL of dichloromethane as the electrolyte, monomer (TTTBD) (0.01 mol / L) as the polymerization monomer, and tetrabutylphosphine hexafluoride (0.1 mol / L) as the supporting electrolyte, polymerization was carried out using a constant potential method. The polymerization potential was 0.85 V, and the polymerization time was 55 s. The polymer film obtained by electrodeposition was rinsed with acetonitrile to remove the electrolyte solution and oligomers generated in the polymer.

[0216] Example 7

[0217] A monomer (denoted as TEEBD) has the following structural formula:

[0218]

[0219] The method for preparing the above monomer includes the following steps:

[0220]

[0221] Specifically:

[0222] Under a nitrogen atmosphere, 1,3-bis(7'-bromo-2,2',3,3'-tetrahydro-[5,5'-bithiophene[3,4-b][1,4]dioxin]-7-yl)-5,7-bis(2-ethylhexyl)-4H,8Hbenzo[1,2-c:4,5-c'-]dithiophene-4,8-dione (0.064 g, 0.055 mmol), tributyl(thiophene-2-yl)stanane (0.049 g, 0.131 mmol), and catalyst Pd(PPh3)4 (0.08 g, excess) were placed in a 250 mL single-necked flask, and TOL (32 mL) and DMF (8 mL) were added and stirred until homogeneous. The mixture was heated to 120 °C and refluxed for 48 hours. After cooling, the product was obtained.

[0223] The obtained product was poured into saturated brine and extracted five times with dichloromethane. The organic layer was then washed with water. The solvent was removed by vacuum distillation and rotary evaporation. Separation was performed using a silica gel column with dichloromethane and petroleum ether mixed in a volume ratio of 1:2 as the eluent. The purified product (monomer) was 32.5 mg in black powder form, with a yield of 50.9%.

[0224] The 1H NMR characterization results of the product (monomer) are as follows: 1 H NMR(400MHz,Chloroform-d)δ7.18(s,2H),7.14(s,2H),6.95(s,2H),4.33(s,16 H), 3.24 (d, J = 64.9Hz, 4H), 1.73 (s, 2H), 1.42–1.08 (m, 20H), 0.99–0.67 (m, 14H).

[0225] A polymer (denoted as P(TEEBD)) has the following structural formula:

[0226]

[0227] The preparation of the above polymer includes the following steps:

[0228]

[0229] Specifically:

[0230] The above polymer was prepared by electrochemical polymerization, which 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 6 mol / L HCl solution to generate an AgCl coating on the surface).

[0231] Using 10 mL of dichloromethane as the electrolyte, TEEBD (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 0.5 V and a polymerization time of 40 s. The polymer film obtained by electrodeposition was rinsed with acetonitrile to remove the electrolyte solution and oligomers generated in the polymer.

[0232] Example 8

[0233] A monomer (denoted as ETTBD) has the following structural formula:

[0234]

[0235] The method for preparing the above monomer includes the following steps:

[0236]

[0237] Specifically:

[0238] Under a nitrogen atmosphere, 1,3-bis(5'-bromo-[2,2'-bithiophene]-5-yl)-5,7-bis(2-ethylhexyl)-4H,8H-benzo[1,2-c:4,5-c'-]dithiophene-4,8-dione (0.25 g, 0.269 mmol), tributyl(2,3-dihydro[3,4-b][1,4]dioxin-5-yl)stanane (0.279 g, 0.646 mmol), and catalyst Pd(PPh3)4 (0.08 g, excess) were placed in a 250 mL single-necked flask, and TOL (32 mL) and DMF (8 mL) were added and stirred until homogeneous. The mixture was heated to 120 °C and refluxed for 48 hours. After cooling, the product was obtained.

[0239] The obtained product was poured into saturated brine and extracted five times with dichloromethane. The organic layer was then washed with water. The solvent was removed by vacuum distillation and rotary evaporation. Separation was performed using a silica gel column with dichloromethane and petroleum ether mixed in a volume ratio of 1:4 as the eluent. The purified product (monomer) was 38.3 mg in black powder form, with a yield of 13.5%.

[0240] The 1H NMR characterization results of the product (monomer) are as follows: 1H NMR(400MHz,Chloroform-d)δ7.61(d,J=4.0Hz,2H),7.11(d,J=3.8Hz,2H),7.06(d,J=4.0Hz,4H),6.17(s,2H ),4.33–4.14(m,8H),3.24(d,J=7.0Hz,4H),1.71(s,3H),1.39–1.20(m,18H),0.85(dt,J=21.0,7.2Hz,13H).

[0241] A polymer (denoted as P(ETTBD)) has the following structural formula:

[0242]

[0243] The preparation of the above polymer includes the following steps:

[0244]

[0245] Specifically:

[0246] The above polymer was prepared by electrochemical polymerization, which 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 6 mol / L HCl solution to generate an AgCl coating on the surface).

[0247] Using 10 mL of dichloromethane as the electrolyte, ETTBD (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 0.7 V and a polymerization time of 80 s. The polymer film obtained by electrodeposition was rinsed with acetonitrile to remove the electrolyte solution and oligomers generated in the polymer.

[0248] Comparative Example

[0249] The only difference between the comparative example and Example 1 is that: Comparative example 1 uses 0.13 mmol / L of asymmetric 5,7-bis(5-bromothiophen-2-yl)-2,3-bis(2-ethylhexyl)benzo[1,2-b:4,5-c]dithiophen-4,8-dione as the acceptor, replacing 1,3-bis(5-bromothiophen-2-yl)-5,7-bis(2-ethylhexyl)-4H,8H-benzo[1,2-c:4,5-c']dithiophen-4,8-dione in Example 1.

[0250] A monomer (denoted as ETTD) has the following structural formula:

[0251]

[0252] The method for preparing the above monomer includes the following steps:

[0253]

[0254] Specifically:

[0255] Under a nitrogen atmosphere, 5,7-bis(5-bromothiophen-2-yl)-2,3-bis(2-ethylhexyl)benzo[1,2-b:4,5-c']dithiophene-4,8-dione (0.1 g, 0.13 mmol), tributyl(2,3-dihydro[3,4-b][1,4]dioxin-5-yl)stanane (0.2 g, excess), and catalyst Pd(PPh3)4 (0.006 g, 0.0052 mmol) were placed in a 250 mL single-necked flask, and TOL (32 mL) and DMF (8 mL) were added and stirred until homogeneous. The mixture was heated to 120 °C and refluxed for 48 hours. After cooling, the product was obtained.

[0256] The product was poured into saturated brine and extracted 4-5 times with dichloromethane. The organic layer was then washed with a small amount of water. The solvent was removed by vacuum distillation and rotary evaporation. The product was then separated by silica gel chromatography with DCM:PE = 1:5 as the eluent. The purified product yielded 45 mg of black lumpy product, with a yield of 38.9%.

[0257] NMR of the product 1 The H NMR spectral data are as follows: 1 H NMR(400MHz,Chloroform-d)δ7.79(dd,J=21.4,4.1Hz,2H),7.17(t,J=3.5Hz,2H),6.24(s,2H),4.35–4.19(m,8H),2.86(dq,J=3 8.0,6.6Hz,2H),2.68(d,J=7.1Hz,2H),1.59(dd,J=12.8,6.1Hz,2H),1.35–1.16(m,19H),0.84(ddd,J=19.3,12.2,7.0Hz,13H).

[0258] A polymer (denoted as P(ETTD)) has the following structural formula:

[0259]

[0260] The preparation of the above polymer includes the following steps:

[0261]

[0262] Specifically:

[0263] The polymer was prepared by electrochemical polymerization, which 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 6 mol / L HCl solution to generate an AgCl coating on the surface).

[0264] Using 10 mL of dichloromethane as the electrolyte, ETTD (0.01 mol / L) as the monomer for polymerization, and tetrabutylphosphine hexafluoride (0.1 mol / L) as the supporting electrolyte, polymerization was carried out using a potentiostatic method with a polymerization potential of 0.85 V and a polymerization time of 40 s. The polymer film obtained by electrodeposition was rinsed with acetonitrile to remove the electrolyte solution and oligomers generated in the polymer.

[0265] Performance testing:

[0266] The electrochromic properties of the polymer (P(ETBD)) prepared in Example 1 were tested, and the test results are as follows: Figure 1 Specifically:

[0267] (1) The spectroelectrochemical spectra of polymer P(ETBD) prepared in Example 1 in the MeCN-Bu4NPF6 (0.1 mol / L) system were tested, and the results are as follows: Figure 1 As shown in (a), Figure 1 In (a), Wavelength is the wavelength and Absorbance is the absorbance. For example... Figure 1 As shown in (a), and combined with visual observation of the polymer's color change, it can be seen that as the potential increases, the polymer's color changes from blue-black to gray (it is blue-black in the completely dedoped state; due to the good optical transmittance of polymer P(ETBD), the optical transmittance has a great influence on the polymer's color change, and the polymer material can change from blue-black in the completely dedoped state to gray in the doped state, with a large color range). This is because the neutral polymer has an absorption peak in both the violet and red light regions, and the neutral polymer appears blue-black; after the polymer is oxidized, the absorption peaks in the violet and red light regions gradually weaken and eventually disappear completely, while the near-infrared absorption peak appears and gradually rises, and the color also changes to gray.

[0268] (2) The transmittance-time curves of polymer P (ETBD) at 1100 nm, 830 nm, 630 nm and 430 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, polymer P (ETBD) has high optical contrast and high coloring efficiency.

[0269] Table 1: Electrochromic parameters of polymer P (ETBD)

[0270]

[0271] The optical transmittance of polymer P(ETBD) was studied using chronoamperometry at wavelengths of 1100 nm, 830 nm, 630 nm, and 430 nm. During the experiment, the time interval between potential step changes was 5 s. Figure 1 As shown in (b), the polymer exhibited good optical contrast and good optical stability at all four wavelengths, especially reaching an optical contrast of 50.93% at 830 nm. In addition, optical transmittance had a significant impact on the color change of the polymer, which could change from a completely dedoped blue-black state to a doped gray state.

[0272] (3) The short-term memory effect of polymer P(EBDD) was tested at a wavelength of 830 nm. Voltages of -0.3 V and 1.1 V were applied, and the transmittance changes of the polymer in the neutral and doped states were recorded, such as... Figure 1 As shown in (c), the transmittance of the polymer changed by 4.3% in the neutral state and by 3.7% in the doped state, which indicates that the polymer has a good short-term memory effect.

[0273] The electrochromic properties of the polymer (P(EEBD)) prepared in Example 2 were tested, and the test results are as follows: Figure 2 Specifically:

[0274] (1) The polymer film deposited on the surface of ITO conductive glass was placed in a three-electrode electrolytic cell containing a 0.1 mol / L tetrabutylphosphine dichloromethane solution. The working electrode was an ITO conductive glass with the 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 polymer film under different voltages was recorded by a UV-Vis spectrometer, thus obtaining the spectroelectrochemical spectrum of the polymer.

[0275] The spectroelectrochemical spectra of polymer P(EEBD) in the MeCN-Bu4NPF6 (0.1 mol / L, i.e., tetrabutylphosphine hexafluoride in acetonitrile) system are shown below. Figure 2 ( Figure 2As shown in (a), and combined with visual observation of the polymer's color change, it can be seen that as the potential increases, the polymer's color changes from dark blue to purple, and finally to purplish-gray (it is dark blue in the completely dedoped state). This is because the neutral polymer has an absorption peak in both the violet and red light regions, and the neutral polymer appears dark blue. After the polymer is oxidized, the absorption peaks in the violet and red light regions gradually weaken, and the absorption peak in the near-infrared region appears and gradually rises, and the color also changes to purple, and finally to purplish-gray.

[0276] The transmittance of polymer films in doped and neutral states at a specific wavelength under a square wave potential is measured using a UV-Vis spectrophotometer, thereby calculating optical contrast, response time, etc. The UV-Vis spectrophotometer records a time-transmittance curve, while the electrochemical workstation records a time-current curve. The coloring efficiency can also be calculated based on these two curves.

[0277] (2) The transmittance-time curves of polymer P (EEBD) at 1100 nm, 990 nm, 660 nm and 440 nm were tested. The response time and coloring efficiency calculated from the time-transmittance curves are shown in Table 2.

[0278] As shown in Table 2, polymer P (EEBD) has a fast response time but generally low coloring efficiency.

[0279] Table 2: Electrochromic parameters of polymer P (EEBD)

[0280]

[0281] The optical transmittance of polymer P(EEBD) was studied using chronoamperometry at wavelengths of 1100 nm, 990 nm, 660 nm, and 440 nm. During the experiment, the time interval between potential step changes was 5 s. Figure 2 ( Figure 2 As shown in (b), where "Transmittance" represents transmittance and "Time" represents time, polymer P(EEBD) exhibits certain optical contrast and good optical stability at all four wavelengths. Furthermore, optical transmittance has a significant impact on the polymer's color change, allowing it to transition from a deep blue in its completely dedoped state to a purple in its doped state.

[0282] Using the constant potential method, a voltage of 10s was applied to the working electrode by an electrochemical workstation, and then a voltage of 2s was applied every 100s. At the same time, the transmittance of the polymer in the oxidized and reduced states at the maximum absorption peak was recorded by a UV-Vis spectrometer, thus obtaining the short-term memory effect spectrum of the polymer.

[0283] (3) The short-term memory effect of polymer P(EEBD) was tested at a wavelength of 660 nm. Voltages of -0.5 V and 1.1 V were applied, and the transmittance changes of the polymer in the neutral and doped states were recorded, such as... Figure 2 ( Figure 2 As shown in (c), “Transmittance” represents transmittance and “Time” represents time. It was found that the transmittance of the polymer changed by 5.9% in the neutral state and by 3.1% in the doped state, which indicates that the polymer has a good short-term memory effect.

[0284] The electrochromic properties of the polymer (P(TTBD)) prepared in Example 3 were tested, and the test results are as follows: Figure 3 Specifically:

[0285] (1) The polymer film deposited on the surface of ITO conductive glass was placed in a three-electrode electrolytic cell containing a 0.1 mol / L tetrabutylphosphine dichloromethane solution. The working electrode was an ITO conductive glass with the 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 polymer film under different voltages was recorded by a UV-Vis spectrometer, thus obtaining the spectroelectrochemical spectrum of the polymer.

[0286] The spectroelectrochemical spectra of polymer P(TTBD) in the MeCN-Bu4NPF6 (0.1 mol / L, i.e., tetrabutylphosphine hexafluoride in acetonitrile) system are shown below. Figure 3 ( Figure 3 As shown in (a), and combined with visual observation of the polymer's color change, it can be seen that as the potential increases, the polymer's color changes from purple to light gray (it is purple in the completely dedoped state; due to the good optical transmittance of polymer P(TTBD), the optical transmittance has a great influence on the color change of the polymer, and the polymer material can change from purple in the completely dedoped state to light gray in the doped state, with a large color range). This is because the neutral polymer has absorption peaks in the yellow and green light regions, and the neutral polymer appears purple; after the polymer is oxidized, the absorption peaks in the yellow and green light regions gradually weaken, and the absorption peaks in the red and near-infrared regions appear and gradually rise, and the color also changes to light gray.

[0287] The transmittance of polymer films in doped and neutral states at a specific wavelength under a square wave potential is measured using a UV-Vis spectrophotometer, thereby calculating optical contrast, response time, etc. The UV-Vis spectrophotometer records a time-transmittance curve, while the electrochemical workstation records a time-current curve. The coloring efficiency can also be calculated based on these two curves.

[0288] (2) The transmittance-time curves of polymer P (TTBD) at 1100 nm, 735 nm, 560 nm and 410 nm were tested. The response time and coloring efficiency calculated from the time-transmittance curves are shown in Table 3.

[0289] As shown in Table 3, polymer P (TTBD) has a fast response time and high coloring efficiency.

[0290] Table 3: Electrochromic parameters of polymer P (TTBD)

[0291]

[0292] The optical transmittance of polymer P(TTBD) was studied using chronoamperometry at wavelengths of 1100 nm, 735 nm, 560 nm, and 410 nm. During the experiment, the time interval between potential step changes was 5 s. Figure 3 ( Figure 3 As shown in (b), where "Transmittance" represents transmittance and "Time" represents time, polymer P(TTBD) exhibits certain optical contrast and good optical stability at all four wavelengths. Furthermore, optical transmittance has a significant impact on the polymer's color change, allowing it to transition from a completely dedoped purple state to a doped light gray state.

[0293] Using the constant potential method, a voltage of 10s was applied to the working electrode by an electrochemical workstation, and then a voltage of 2s was applied every 100s. At the same time, the transmittance of the polymer in the oxidized and reduced states at the maximum absorption peak was recorded by a UV-Vis spectrometer, thus obtaining the short-term memory effect spectrum of the polymer.

[0294] (3) The short-term memory effect of polymer P(TTBD) was tested at a wavelength of 1100 nm. Voltages of 0 V and 1.2 V were applied, and the transmittance changes of the polymer in the neutral and doped states were recorded, such as... Figure 3 ( Figure 3 As shown in (c), “Transmittance” represents transmittance and “Time” represents time. It was found that the transmittance of the polymer in the neutral state changed by 0.1% and the transmittance in the doped state changed by 5.2%, which indicates that the polymer has a good short-term memory effect.

[0295] The electrochromic properties of the polymer (P(TEBD)) prepared in Example 4 were tested, and the test results are as follows: Figure 4 Specifically:

[0296] (1) The spectroelectrochemical spectra of polymer P(TEBD) in the MeCN-Bu4NPF6 (0.1 mol / L) system are shown below. Figure 4 As shown in (a), and combined with visual observation of the polymer's color change, it can be seen that as the potential increases, the polymer's color changes from blue-violet to light blue (it is blue-violet in the completely undoped state; since the optical transmittance of polymer P(TEBD) is generally low, the color range of the polymer material from the completely undoped state to the doped state light blue is generally low). This is because the neutral state polymer has an absorption peak in the blue light region, and the neutral state polymer appears blue-violet. After the polymer is oxidized, the absorption peak in the blue light region gradually weakens, and the absorption peaks in the red light region and near-infrared region appear and gradually rise, and the color also changes to light blue.

[0297] (2) The transmittance-time curves of polymer P (TEBD) at 1100 nm, 730 nm and 485 nm were tested. The response time and coloring efficiency calculated from the time-transmittance curves are shown in Table 4.

[0298] Table 4: Electrochromic parameters of polymer P (TEBD)

[0299]

[0300] The optical transmittance of polymer P(TEBD) was studied using chronoamperometry at wavelengths of 1100 nm, 730 nm, 560 nm, and 485 nm. During the experiment, the time interval between potential step changes was 5 s. Figure 4 ( Figure 4 In Figure (b), “Transmittance” represents transmittance and “Time” represents time. At four wavelengths, polymer P (TEBD) exhibits certain optical contrast and good optical stability. In addition, optical transmittance has a significant impact on the color change of the polymer, which can change from a completely dedoped blue-violet state to a doped light blue state.

[0301] (3) The short-term memory effect of polymer P(TEDD) was tested at a wavelength of 1100 nm. Voltages of 0.1 V and 1.3 V were applied, and the transmittance changes of the polymer in the neutral and doped states were recorded, such as... Figure 4 As shown in (c), the transmittance of the polymer in the neutral state changed by 0.1%, while the transmittance in the doped state changed by 12%, indicating a general short-term memory effect.

[0302] The electrochromic properties of the polymer (P(EEEBD)) prepared in Example 5 were tested, and the test results are as follows: Figure 5 Specifically:

[0303] (1) The spectroelectrochemical spectra of polymer P(EEEBD) in the MeCN-Bu4NPF6 (0.1 mol / L) system were tested, as shown in the figure. Figure 5 As shown in (a), and combined with visual observation of the polymer's color change, it can be seen that as the potential increases, the polymer's color changes from purple to blue (purple in the completely dedoped state; due to the good optical transmittance of polymer P(EEEBD), the optical transmittance has a great influence on the polymer's color change, and the polymer material can change from purple in the completely dedoped state to blue in the doped state, with a large color range). This is because the neutral polymer has an absorption peak in both the violet and green light regions, and the neutral polymer appears purple; after the polymer is oxidized, the absorption peaks in the violet and green light regions gradually weaken, and the absorption peak in the near-infrared region appears and gradually rises, and the color also changes to blue.

[0304] (2) The transmittance-time curves of polymer P (EEEBD) at 1100 nm, 800 nm, 543 nm and 390 nm were tested. The response time and coloring efficiency calculated from the time-transmittance curves are shown in Table 5.

[0305] Table 5: Electrochromic parameters of polymer P (EEEDD)

[0306]

[0307] The optical transmittance of polymer P (EEEBD) was studied using chronoamperometry at wavelengths of 1100 nm, 800 nm, 543 nm, and 390 nm. During the experiment, the time interval between potential step changes was 5 s. Figure 5 ( Figure 5 In Figure (b), “Transmittance” represents transmittance and “Time” represents time. At all four wavelengths, polymer P(EEEBD) exhibited a certain degree of optical contrast and good optical stability.

[0308] (3) The short-term memory effect of polymer P(EEEBD) was tested at a wavelength of 1100 nm. Voltages of -0.3 V and 1.1 V were applied, and the transmittance changes of the polymer in the neutral and doped states were recorded, such as... Figure 5 As shown in Figure (v), the transmittance of the polymer changes by 1.2% in the neutral state and by 3.9% in the doped state, indicating that the polymer has a good short-term memory effect.

[0309] The electrochromic properties of the polymer (P(TTTBD)) prepared in Example 6 were tested, and the test results are as follows: Figure 6 Specifically:

[0310] (1) The spectroelectrochemical spectra of polymer P(TTTBD) in the MeCN-Bu4NPF6 (0.1 mol / L) system are shown in the figure. Figure 6 As shown in (a), and combined with visual observation of the polymer's color change, it can be seen that as the potential increases, the polymer's color changes from purple to blue-black (purple in the completely dedoped state; due to the good optical transmittance of polymer P(TTTBD), the optical transmittance has a great influence on the polymer's color change, and the polymer material can change from purple in the completely dedoped state to blue-black in the doped state, with a large color range). This is because the neutral polymer has an absorption peak in both the green and yellow light regions, and the neutral polymer appears purple; after the polymer is oxidized, the absorption peaks in the green and yellow light regions gradually weaken, while the absorption peaks in the red and near-infrared regions appear and gradually rise, and the color also changes to blue-black.

[0311] (2) The transmittance-time curves of polymer P (TTTBD) at 1100 nm, 765 nm, 535 nm and 420 nm were tested. The response time and coloring efficiency calculated from the time-transmittance curves are shown in Table 6.

[0312] Table 6: Electrochromic parameters of polymer P (TTTBD)

[0313]

[0314] The optical transmittance of polymer P(TTTBD) was studied using chronoamperometry at wavelengths of 1100 nm, 765 nm, 535 nm, and 420 nm. During the experiment, the time interval between potential step changes was 5 s. Figure 6 ( Figure 6 In Figure (b), “Transmittance” represents transmittance and “Time” represents time. At all four wavelengths, polymer P(TTTBD) exhibited a certain degree of optical contrast and good optical stability.

[0315] (3) The short-term memory effect of polymer P(TTTBD) was tested at a wavelength of 1100 nm. Voltages of 0.4 V and 1.4 V were applied, and the transmittance changes of the polymer in the neutral and doped states were recorded, such as... Figure 6 As shown in (c), the transmittance of the polymer in the neutral state changed by 0.5%, while the transmittance in the doped state changed by 12.7%, indicating that the short-term memory effect of the polymer is generally normal.

[0316] The electrochromic properties of the polymer (P(TEEBD)) prepared in Example 7 were tested, and the test results are as follows: Figure 7 Specifically:

[0317] (1) The spectroelectrochemical spectra of polymer P(TEEBD) in the MeCN-Bu4NPF6 (0.1 mol / L) system were tested, as shown in the figure. Figure 7 As shown in (a), and combined with visual observation of the polymer's color change, it can be seen that as the potential increases, the polymer's color changes from purplish-red to light blue (purplish-red in the completely dedoped state). This is because the neutral polymer has an absorption peak in both the violet and green light regions, and the neutral polymer appears purplish-red. After the polymer is oxidized, the absorption peaks in the violet and green light regions gradually weaken, and the absorption peak in the near-infrared region appears and gradually rises, and the color also changes to light blue.

[0318] (2) The transmittance-time curves of polymer P (TEEBD) at 1100 nm, 650 nm, 525 nm and 380 nm were tested. The response time and coloring efficiency calculated from the time-transmittance curves are shown in Table 7. As can be seen from Table 7, polymer P (TEEBD) has high optical contrast and high coloring efficiency.

[0319] Table 7: Electrochromic parameters of polymer P (TEEBD)

[0320]

[0321] The optical transmittance of polymer P (TEEBD) was studied using chronoamperometry at wavelengths of 1100 nm, 650 nm, 525 nm, and 380 nm. During the experiment, the time interval between potential step changes was 5 s. Figure 7 ( Figure 7 In Figure (b), “Transmittance” represents transmittance and “Time” represents time. At all four wavelengths, polymer P(TEEBD) exhibited a certain degree of optical contrast and good optical stability.

[0322] (3) The short-term memory effect of polymer P(TEEBD) was tested at a wavelength of 1100 nm. Voltages of -0.1 V and 1.1 V were applied, and the transmittance changes of the polymer in the neutral and doped states were recorded, such as... Figure 7 As shown in (c), the transmittance of the polymer changed by 0.2% in the neutral state and by 6.2% in the doped state, which indicates that the polymer has a good short-term memory effect.

[0323] The electrochromic properties of the polymer (P(ETTBD)) prepared in Example 8 were tested, and the test results are as follows: Figure 8 Specifically:

[0324] (1) The spectroelectrochemical spectra of polymer P (ETTBD) in the MeCN-Bu4NPF6 (0.1 mol / L) system were tested, as shown in the figure. Figure 8 As shown in (a), and combined with visual observation of the polymer's color change, it can be seen that as the potential increases, the polymer's color changes from light gray to blue (it is light gray in the completely dedoped state; due to the good optical transmittance of polymer P (ETTBD), the optical transmittance has a great influence on the polymer's color change, and the polymer material can change from light gray in the completely dedoped state to blue in the doped state, with a large color range). This is because the neutral polymer has an absorption peak in the green and yellow light regions, and the neutral polymer appears light gray; after the polymer is oxidized, the absorption peaks in the green and yellow light regions gradually weaken, and the near-infrared absorption peak appears and gradually rises, and the color also changes to blue.

[0325] (2) The transmittance-time curves of polymer P (ETTBD) at 1100 nm, 800 nm, 600 nm and 480 nm were tested. The response time and coloring efficiency calculated from the time-transmittance curves are shown in Table 8. As can be seen from Table 8, polymer P (ETTBD) has high optical contrast and high coloring efficiency.

[0326] Table 8: Electrochromic parameters of polymer P (ETTBD)

[0327]

[0328]

[0329] The optical transmittance of polymer P (ETTBD) was studied using chronoamperometry at wavelengths of 1100 nm, 800 nm, 600 nm, and 480 nm. During the experiment, the time interval between potential step changes was 5 s. Figure 8 ( Figure 8 In Figure (b), “Transmittance” represents transmittance and “Time” represents time. At all four wavelengths, polymer P (ETTBD) exhibited a certain degree of optical contrast and good optical stability.

[0330] (3) The short-term memory effect of polymer P (ETTBD) was tested at a wavelength of 800 nm. Voltages of -0.1 V and 1.3 V were applied, and the transmittance changes of the polymer in the neutral and doped states were recorded, such as... Figure 8As shown in (c), the transmittance of the polymer changed by 1.1% in the neutral state and by 3.2% in the doped state, which indicates that the polymer has a good short-term memory effect.

[0331] The electrochromic properties of the polymer (P(ETTD)) prepared in the comparative example were tested, and the test results are as follows: Figure 9 Specifically:

[0332] (1) The spectroelectrochemical spectra of the polymer P(ETTD) prepared in the comparative example were tested in the MeCN-Bu4NPF6 (0.1 mol / L) system. The results are as follows: Figure 9 As shown in (a), Figure 9 In (a), Wavelength is the wavelength and Absorbance is the absorbance. For example... Figure 9 As shown in (a), and combined with visual observation of the polymer's color change, it can be seen that as the potential increases, the polymer's color changes from deep blue to blue-gray (it is deep blue in the completely dedoped state; due to the poor optical transmittance of polymer P(ETTD), the polymer material can change from deep blue in the completely dedoped state to blue-gray in the doped state, with a small color range). This is because the neutral polymer has an absorption peak in both the violet and red light regions, and the neutral polymer appears as deep blue. After the polymer is oxidized, the absorption peaks in the violet and red light regions gradually weaken and eventually disappear completely, while the near-infrared absorption peak appears and gradually rises, and the color also changes to blue-gray.

[0333] (2) The transmittance-time curves of polymer P (ETTD) at 1100 nm, 900 nm, 678 nm, and 420 nm were tested. The response time and coloring efficiency calculated from the time-transmittance curves are shown in Table 9. As can be seen from Table 9, polymer P (ETBD) has a relatively fast response time but a moderate coloring efficiency. Compared with Example 1, the comparative example uses an asymmetric acceptor, which changes the electron-withdrawing ability of the acceptor in the DA structure, affecting the band gap and ultimately the coloring efficiency.

[0334] Table 9: Electrochromic parameters of polymer P (ETTD)

[0335]

[0336] The optical transmittance of polymer P(ETTD) was studied using chronoamperometry at wavelengths of 1100 nm, 900 nm, 678 nm, and 420 nm. During the experiment, the time interval between potential step changes was 5 s. Figure 9As shown in (b), the polymer material exhibits certain optical contrast and good optical stability at all four wavelengths. Furthermore, the optical transmittance has a significant impact on the color change of the polymer, which can change from a deep blue in the completely dedoped state to a blue-gray in the doped state.

[0337] (3) The short-term memory effect of P(ETTD) was tested at a wavelength of 1100 nm. Voltages of -0.3 V and 1.1 V were applied, and the transmittance changes of the polymer in the neutral and doped states were recorded, such as... Figure 9 As shown in (c), the transmittance of the polymer changed by 1.5% in the neutral state and by 5.2% in the doped state, which indicates that the polymer has a good short-term memory effect.

[0338] The response time and coloring efficiency of the polymers prepared in Examples 1-8 at a wavelength of 1100 nm were statistically analyzed, and Table 10 was obtained.

[0339] Table 10

[0340]

[0341] The polymer structures of Examples 1 and 2 differ in that π is a thiophene group, while D is an EDOT group in both examples; however, the π in Example 1 is a thiophene group, while the π in Example 2 is an EDOT group. The coloring efficiency CE of Example 1 is 129.79 cm⁻¹. 2 C -1 The coloring efficiency (CE) of Example 2 was 158.33 cm⁻¹. 2 C -1 This indicates that when all D groups are EDOT groups, the π structure being EDOT is more conducive to improving coloring efficiency.

[0342] In the polymer structure of Example 3, both π and D are thiophene groups. The polymer of Example 3 with four thiophene groups has the highest coloring efficiency among Examples 1-8. This indicates that the combination of four thiophene groups is more conducive to improving coloring efficiency, and that thiophene groups are more conducive to improving coloring efficiency than EDOT groups.

[0343] The polymer structures of Example 4 and Example 3 are different in that π is a thiophene group in Example 3 and an EDOT group in Example 4. Compared with Example 3, Example 4 has a worse coloring efficiency. This is attributed to the fact that the energy level difference between thiophene and EDOT may cause local interruption of the conjugated chain, which hinders electron delocalization and requires more charge compensation to achieve the same ΔOD.

[0344] Example 5 contains three EDOT groups, while Example 2 contains two EDOT groups. The coloring efficiency (CE) of Example 5 is lower than that of Example 2, indicating that excessive elongation of the conjugated structure affects the coloring efficiency.

[0345] In the polymer structure of Example 6, both π and D are thiophene groups, and there are a total of six thiophene groups, which is two more than that of Example 3. The coloring efficiency of Example 6 is lower than that of Example 3. The deterioration of the coloring performance of the polymer in Example 6 may be attributed to the effect of the elongation of its conjugated structure on the coloring efficiency.

[0346] Example 7 introduces a thiophene group based on Example 2. Although the conjugated structure is lengthened, the coloring efficiency is improved because D is a thiophene group, indicating that the thiophene group is more beneficial to improving coloring efficiency than the EDOT group.

[0347] Compared with Example 6, Example 8 replaced the thiophene group in D of Example 6 with the EDOT group, resulting in a decrease in coloring efficiency.

[0348] The comparative example showed the worst color efficiency, with a color efficiency of 92.19 cm. 2 C -1 Example 1 is 129.79 cm. 2 C -1 The reason is that the comparative sample contains asymmetric thiophene, which also proves that symmetric acceptors are more conducive to improving staining efficiency.

[0349] The above are merely embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention specification, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A monomer characterized in that, The specific structure is as follows: ， ， ， ， 。 2. A process for the preparation of a monomer as claimed in claim 1, characterized in that, The method comprises the following steps: A compound corresponding to the monomer, a catalyst, tributyl(2,3-dihydro[3,4-b][1,4]dioxin-5-yl)stannane or tributyl(2-thiophenyl)stannane are mixed in a solvent under a protective gas atmosphere, and then reacted to obtain the monomer; The compound A corresponding to the monomer has the following structural formula: ， , or .

3. The method of claim 2, wherein, The mass ratio of the compound A to the tributyl(2,3-dihydro[3,4-b][1,4]dioxin-5-yl)stannane is 0.1-0.12:0.1-0.

5.

4. A polymer characterized by, The raw material of the polymer comprises the monomer according to claim 1.

5. A process for the preparation of the polymer according to claim 4, characterized in that, The method comprises the following steps: An electrolyte and the monomer are mixed in a solvent to obtain an electrolyte solution, the electrolyte solution is added to an electrode system, and then an electrochemical polymerization reaction is performed to deposit the polymer.

6. An electrochromic material characterized in that, The polymer comprises the polymer according to claim 4.

7. An electrochromic device, characterized in that, The electrochromic material comprises the electrochromic material according to claim 6.

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