Multiband electrochromic polymer, electrochromic film, electrochromic device and preparation method thereof

Abstract

The invention provides a multiband electrochromic polymer, an electrochromic film, an electrochromic device and a preparation method of the multiband electrochromic polymer, and relates to the technical field of electrochromic materials.The preparation method of the electrochromic film comprises the steps that the multiband electrochromic polymer is dispersed in an organic solvent, and an electrochromic medium is obtained; preparing the electrochromic medium into an electrochromic film by adopting a spin coating method or a blade coating method; and the electrochromic film is placed in a dopant solution to be doped. The invention is beneficial to improving the defects of poor solubility and low optical contrast of the current polythiophene-based electrochromic molecule; and rhodamine electrochromic materials are poor in micromolecule film-forming property and easy to diffuse, and optical signal change is only limited to visible light band.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochromic materials, and more particularly, to multi-band electrochromic polymers, electrochromic films, electrochromic devices and their preparation methods. Background Art

[0002] Electrochromism refers to the reversible redox reaction that occurs in a material under the action of an external electric field, or the injection and extraction of charges within a molecule, which in turn causes a reversible change in the optical properties (such as absorbance, transmittance, or reflectance) of the material. Electrochromic polymers such as polythiophene, polypyrrole, polyaniline, and certain rhodamine molecules can all be used as electrochromic materials.

[0003] Polythiophene is a class of electrochromic polymer molecules with excellent charge transport properties, and its carriers are holes. Based on the electrochromic device of polythiophene, under the stimulation of an external electric field, through the electro-controlled "doping" and "dedoping" mechanisms, stable electrochromism can be achieved. Generally speaking, the polythiophene electrochromic film is in the colored state in the intrinsic state and shows colorless in the oxidized state. In addition, polythiophene-based electrochromic materials also have adjustable broad-spectrum (visible light region, near and mid-infrared regions) photophysical characteristics.

[0004] However, at the present stage, polythiophene-based electrochromic materials and devices still have some disadvantages. Specifically, they include: (1) The molar extinction coefficient of polythiophene is relatively low, resulting in a low optical contrast; (2) The color change mode of traditional polythiophene is "colored - colorless", which will limit its application scenarios; (3) Due to the characteristics of the rigid structure of the traditional polythiophene backbone unit, the solubility of this type of molecule is poor, and it cannot be well dispersed in water or organic solvents, making it difficult to process, which greatly limits the application of polythiophene-based electrochromic materials.

[0005] Rhodamine-based electrochromic small molecules have the advantages of bright colors and high molar extinction coefficients. In existing rhodamine-based electrochromic systems, the electrochromic acid part and the acid-responsive part are two groups of the same molecule or a combination of two different molecules. When the electrochromic acid is oxidized, protons are transferred from the electrochromic acid group on the organic small molecule to the acid-responsive group, or from the electrochromic acid molecule to the acid-responsive molecule; when the oxidized electrochromic acid is reduced, the protons are transferred from the acid-responsive group on the organic small molecule to the electrochromic acid group, or from the acid-responsive molecule to the electrochromic acid molecule. The partial acceptance and donation of protons by the acid-responsive group will cause a change in its color.

[0006] However, there are also some disadvantages in the current rhodamine-based electrochromic materials and devices, specifically including: (1) Rhodamine-based molecules only have optical signal changes in the ultraviolet and visible light regions, lacking the ability to regulate optical signals in the long-wavelength region; (2) Rhodamine-based organic small molecules cannot form films alone and have limited solubility, making them difficult to process. As a result, there are fewer coloring units, leading to a relatively low optical contrast in electrochromism; (3) The diffusion effect of rhodamine-based organic small molecules is obvious. After being colored by electric stimulation, the organic small molecules will diffuse away from the electrode, resulting in color attenuation of the device and a poor bistable effect of the device; when applying a reverse voltage, due to the diffusion of the colored molecules or electrochromic acid molecules away from the electrode, the device fades slowly. At the same time, due to the very poor charge transport performance of rhodamine-based molecules, the electron transfer, which is the rate-determining step, is limited, jointly leading to a slow response speed of the electrochromic device. Summary of the Invention

[0007] The present invention aims to simultaneously improve and solve the problems existing in current polythiophene-based and rhodamine-based electrochromic materials and devices. That is, currently, the electrochromic molecules based on polythiophene have poor solubility and low optical contrast; and the rhodamine-based electrochromic materials have poor film-forming properties of small molecules, are prone to diffusion, and the optical signal changes are limited to the visible light region band.

[0008] To solve the above problems, the present invention provides a multi-band electrochromic polymer, an electrochromic film, an electrochromic device, and a preparation method thereof.

[0009] In a first aspect, the present invention relates to a multi-band electrochromic polymer, and the structural formula of the multi-band electrochromic polymer is any one of Formula I to Formula XI:

[0010]

[0011] In Formula I to Formula XI, n is from 1 to 200, x is from 1 to 50, and y is from 1 to 50;

[0012] The structural formula of P1 and / or P2 is Wherein, m is from 1 to 24, and the structural formula of B is any one of Formula XII, Formula XIII, or the structural formula obtained by connecting at least two groups among R3, R4, R5, R6, R7, and R8 of Formula XII and Formula XIII respectively:

[0013]

[0014] In Formula I to Formula XIII, R1, R2, R3, R4, R5, R6, R7, R8, and R9 are respectively H, halogen, hydroxyl group, amino group, C1 to C 24 alkyl groups between, C1 to C 24 alkyloxy groups between, C1 to C 24Substituted alkyloxy groups, C1 to C 24 Ester groups, C1 to C 24 Substituted alkyl ester groups, C1 to C 24 Alkylamino groups, and C6 to C 24 Any one of aryl groups;

[0015] Y is any one of an O atom, an S atom, and Si(CH3)2;

[0016] Z1 is H, C1 to C 24 Alkyl groups, C1 to C 24 Substituted alkyl groups, C1 to C 24 Acyl groups, C1 to C 24 Alkoxy groups, and C6 to C 24 Any one of aryl groups;

[0017] Ar1, Ar2, and Ar3 are each an aromatic ring or a substituted aromatic ring having C6 to C 12 An aromatic ring or a substituted aromatic ring having C6 to C.

[0018] In a second aspect, the present invention relates to an electrochromic film, and the material of the electrochromic film includes the above-mentioned multi-band electrochromic polymer.

[0019] Optionally, the thickness of the electrochromic film is 50 nm to 50 μm.

[0020] In a third aspect, the present invention relates to a method for preparing an electrochromic film, which is used to prepare the above-mentioned electrochromic film, and includes:

[0021] Dispersing the multi-band electrochromic polymer in an organic solvent to obtain an electrochromic medium, and using a spin coating method to form the electrochromic medium into an electrochromic film;

[0022] Placing the electrochromic film in a dopant solution for doping to obtain a final electrochromic film.

[0023] Optionally, the solute of the dopant solution is any one of a mixture of a benzoquinone and hydroquinone redox pair, a mixture of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and hydroquinone redox pair, benzoquinone and its derivatives, tetrafluorotetracyanoquinodimethane and its derivatives, Cu(II) salts, Fe(III) salts, Fe(II) salts, Zn(II) salts, Mn salts and other variable-valence metal salts; the solvent of the dopant solution is any one of acetonitrile, water, or propylene carbonate.

[0024] Optionally, the molar ratio of the solute in the dopant solution to the multi-band electrochromic polymer in the electrochromic medium is (1 to 1,000,000):1.

[0025] Optionally, when the electrochromic medium is made into an electrochromic film by spin coating, it includes:

[0026] Drop the electrochromic medium onto the substrate, and then rotate the substrate to make the electrochromic medium spread evenly. Among them, the rotation speed of the substrate is 500 rpm to 5000 rpm, and the spin coating time is 5 s to 5 min.

[0027] Optionally, when the electrochromic medium is made into an electrochromic film by blade coating, it includes:

[0028] Drop the electrochromic medium onto the substrate, and then use a doctor blade or a wire bar to scrape the electrochromic medium until it spreads evenly. Among them, the height of the wet film during scraping is 5 μm to 500 μm, and the moving speed of the doctor blade or the wire bar is 10 mm / s to 60 mm / s.

[0029] Optionally, when doping the electrochromic film in a dopant solution, the doping time is 30 s to 30 min.

[0030] In a fourth aspect, the present invention relates to an electrochromic device, which includes a first electrode, an electrochromic layer, an ion transport layer, an ion storage layer, and a second electrode stacked in sequence. The electrochromic layer includes the above-mentioned electrochromic film.

[0031] The beneficial effects of the present invention compared with the prior art are:

[0032] Through the design of the synthesis route, the present invention introduces side chain groups such as long alkyl chains to modify the polythiophene backbone unit, improves the solubility of polymer molecules, and grafts rhodamine units onto the polythiophene backbone unit. Through the direct arylation polymerization method, a electrochromic polymer molecule with good solubility is synthesized. First, the multi-band electrochromic polymer in the present invention can limit the diffusion of small molecules of rhodamine-based electrochromic materials, facilitate film formation, increase the number of color-changing units after film formation, and combine with the high molar extinction coefficient of rhodamine molecules, resulting in a higher overall optical contrast of the electrochromic polymer. Secondly, the present invention combines rhodamine molecules with polythiophene molecules, which can not only have a high optical signal modulation ability in the visible light region of rhodamine molecules, that is, a high optical contrast, but also have the photophysical characteristics of polythiophene molecules in the near-infrared region, enabling the same molecule and material to achieve multi-band optical signal regulation in a long spectral range. Finally, the present invention further improves the charge transport ability of the electrochromic film through chemical doping, and improves the multi-stable state performance and response speed of the device. It has been experimentally verified that the electrochromic device further constructed from the electrochromic polymer in the embodiments of the present invention has the optical modulation ability of multi-color in multi-bands of a long spectrum, faster response speed (coloring speed, fading speed), and longer three-stable state retention time. Description of the Drawings

[0033] Figure 1 Schematic diagram of the electrochromic mechanism of the polythiophene backbone unit in the embodiment of the present invention;

[0034] Figure 2 Schematic diagram of the electrochromic mechanism of the rhodamine unit in the embodiment of the present invention;

[0035] Figure 3 Schematic diagram of the structure of the electrochromic device in the embodiment of the present invention;

[0036] Figure 4 SEM image of the surface of the electrochromic film in Example 1 of the present invention;

[0037] Figure 5 Cross-sectional SEM image of the electrochromic film in Example 1 of the present invention;

[0038] Figure 6 Ultraviolet-visible-near-infrared absorption spectrum of the electrochromic device in Example 1 of the present invention;

[0039] Figure 7 Response speed characterization diagram of the electrochromic device in Example 1 of the present invention;

[0040] Figure 8 Tri-stable performance diagram of the electrochromic device after applying voltages of +0.4V, +2.0V, and -1.0V respectively in Example 1 of the present invention;

[0041] Figure 9 Synthesis process flow chart of the multi-band electrochromic polymer in Example 4 of the present invention;

[0042] Figure 10 Synthesis process flow chart of the multi-band electrochromic polymer in Example 7 of the present invention;

[0043] Figure 11 Synthesis process flow chart of the multi-band electrochromic polymer in Example 8 of the present invention;

[0044] Figure 12 Synthesis process flow chart of the multi-band electrochromic polymer in Example 9 of the present invention;

[0045] Figure 13 Synthesis process flow chart of the multi-band electrochromic polymer in Example 10 of the present invention;

[0046] Figure 14 Synthesis process flow chart of the multi-band electrochromic polymer in Example 11 of the present invention;

[0047] Description of the reference numerals:

[0048] 1. First electrode; 2. Electrochromic layer; 3. Ion transport layer; 4. Ion storage layer; 5. Second electrode. Detailed implementation mode

[0049] To make the above objects, features and advantages of the present invention more obvious and understandable, the following will describe in detail the specific embodiments of the present invention with reference to the accompanying drawings.

[0050] The present invention aims to improve the problems of poor solubility and low optical contrast of current electrochromic molecules based on polythiophene; and poor film-forming property, easy diffusion of small-molecule rhodamine-based electrochromic materials, and optical signal changes limited to the visible light band.

[0051] To solve the above problems simultaneously, the embodiments of the present invention provide a multi-band electrochromic polymer, an electrochromic film, an electrochromic device and a preparation method thereof.

[0052] As a first aspect, the present invention provides a multi-band electrochromic polymer, and the multi-band electrochromic polymer is any one of Formulas I to XI:

[0053]

[0054] In Formulas I to XI, n is from 1 to 200, x is from 1 to 50, and y is from 1 to 50;

[0055] The structural formula of P1 and / or P2 is Among them, m is from 1 to 24, and the structural formula of B is any one of Formula XII, Formula XIII, or the structural formula obtained by connecting at least two groups among R3, R4, R5, R6, R7, and R8 of Formula XII and Formula XIII respectively:

[0056]

[0057] In Formulas I to XIII, R1, R2, R3, R4, R5, R6, R7, R8, and R9 are respectively H, halogen, hydroxyl group, amino group, C1 to C 24 alkyl group between, C1 to C 24 alkyloxy group between, C1 to C 24 substituted alkyloxy group between, C1 to C 24 ester group between, C1 to C 24 substituted alkyl ester group between, C1 to C 24 alkylamino group between and C6 to C 24 aryl group between any one of; Y is any one of O atom, S atom and Si(CH3)2; Z1 is H, C1 to C 24 alkyl group between, C1 to C 24 substituted alkyl group of, C1 to C 24 acyl group between, C1 to C24 any one of the alkoxy groups between and C6 to C 24 and any one of the aryl groups; Ar1, Ar2, and Ar3 are each an aromatic ring or a substituted aromatic ring between C6 and C 12 among them.

[0058] Through the design of the synthetic route, the present invention introduces side chain groups such as long alkyl chains to modify the polythiophene backbone unit, improves the solubility of polymer molecules, and grafts rhodamine units onto the polythiophene backbone unit. Through the direct arylation polymerization method, a multi-band electrochromic polymer molecule with good solubility is synthesized.

[0059] First of all, the multi-band electrochromic polymer in the present invention can limit the diffusion of small molecules of rhodamine-based electrochromic materials, which is beneficial for film formation, increasing the number of color-changing units after film formation. Combining with the high molar extinction coefficient of rhodamine molecules, the overall optical contrast of the electrochromic polymer is higher. Secondly, the present invention combines rhodamine molecules with polythiophene molecules, which can not only have a high optical signal modulation ability in the visible light region of rhodamine molecules, that is, a high optical contrast, but also have the photophysical characteristics of polythiophene molecules in the near-infrared region, enabling the same molecule and material to achieve multi-band optical signal regulation in a long spectral range.

[0060] It should be noted that in the multi-band electrochromic polymer of the embodiments of the present invention, the polythiophene backbone unit is shown in Formulas I to XI, and the rhodamine unit can be Formula XII, Formula XIII, or a structural formula obtained by connecting at least two of the R3, R4, R5, R6, R7, and R8 in Formula XII and Formula XIII respectively (such as Formula III-1 in Example 3). That is, at least two of the R3, R4, R5, R6, R7, and R8 in Formula XII can be connected to form a new structural formula, and at least two of the R3, R4, R5, R6, R7, and R8 in Formula XII can also be connected to form a new structural formula.

[0061] Furthermore, the rhodamine unit can be specifically connected to the P1 and / or P2 positions of the polythiophene backbone unit. Specifically, it can be that both the P1 and P2 positions in Formulas I to XI are connected with rhodamine units, or one of the P1 and P2 positions is connected with a rhodamine unit, and the other is H, halogen, hydroxyl, amino, C1 to C 24 alkyl groups between, C1 to C 24 alkyloxy groups between, C1 to C 24 substituted alkyloxy groups between, C1 to C 24 ester groups between, C1 to C 24 substituted alkyl ester groups between, C1 to C 24 alkylamino groups between and C6 to C 24 and any one of the aryl groups.

[0062] As a second aspect, the present invention provides an electrochromic film, and the material of the electrochromic film includes the above-mentioned multi-band electrochromic polymer. Specifically, the thickness of the electrochromic film is 50 nm to 50 μm.

[0063] As a third aspect, the present invention further provides a method for preparing an electrochromic film, which is used to prepare the above-mentioned electrochromic film, and specifically includes: dispersing the multi-band electrochromic polymer in an organic solvent to obtain an electrochromic medium, and using a spin coating method to form the electrochromic medium into an electrochromic film; doping the electrochromic film in a dopant solution.

[0064] In the embodiment of the present invention, the synthesized multi-band electrochromic polymer is dissolved in an organic solvent, and an electrochromic polymer film is prepared by a spin coating method or a doctor blade method. Further, the film is doped with a chemical dopant to obtain a colorless electrochromic film with high transmittance, and an electrochromic device is further constructed to change the traditional "coloring - colorless" color change mode of the electrochromic device based on polythiophene molecules. The present invention utilizes the different response voltages of different units, and by regulating the magnitude of the stimulating voltage, the change of three colors of "colorless and transparent", "colored state 1", and "colored state 2" is realized, further expanding the application scenarios of electrochromic devices. And through the non-covalent interaction (coordination interaction, Coulomb effect, etc.) between the dopant and the polymer, it is beneficial to stabilize the high-energy states of polythiophene and rhodamine structures during the electrochromic process, improve the multi-stable performance of the device, and improve the charge transport performance of the molecules, thereby improving the response speed of the device, and solving the problems of poor memory effect and slow response speed of traditional electrochromic devices.

[0065] Specifically, the electrochromic mechanism of the polythiophene backbone unit is as Figure 1 shown (taking Formula I as an example): There is a synergistic effect of charge transfer between the polythiophene backbone unit and the dopant and the embedding of charge-balanced anions, so that the sulfur holes on the polythiophene backbone unit are stabilized by non-covalent interaction, promoting the stable existence of the electrochromic film in the oxidized state. Under the action of an external electric field, based on its unique anion doping and de-doping mechanism and the coupling relationship of electro-responsive non-covalent interaction, a good steady state (memory effect) effect is ensured, and the polythiophene backbone unit shows a reversible transformation between the colorless and transparent oxidized state and the colored reduced state. With different degrees of conjugation, the colors of color change are different. Therefore, under the stimulation of an external electric field, different color changes and optical signal modulation can be realized in the ultraviolet - visible - near-infrared spectral range.

[0066] The electrochromic mechanism of the rhodamine unit is as Figure 2As shown (taking Formula XIII as an example): Under a positive voltage, the aromatic aniline part of the color-changing unit in the rhodamine unit is oxidized, releasing protons. The fluorane part obtains protons, resulting in a color change. Fluoranes with different substituents have different color-changing colors. At the same time, the electrochromic film adheres to the electrode surface. The excellent charge transport performance of the polythiophene backbone and the short electrode distance ensure a fast response speed. The conjugated electrochromic polymer backbone has a concentration effect, that is, it can graft color-changing units at a high density, thereby ensuring a high color-changing intensity, preventing the diffusion of the aromatic aniline part, and ensuring high steady-state performance.

[0067] In some alternative embodiments, the organic solvent can be one or more of tetrahydrofuran, n-hexane, chlorobenzene, xylene, γ-butyrolactone, dichloromethane, ethyl acetate, anisole, etc. The concentration of the multi-band electrochromic polymer in the organic solvent can be from 1 mg / mL to 50 mg / mL.

[0068] In some alternative embodiments, the solute in the dopant solution is a mixture of a p-benzoquinone and hydroquinone redox pair, a mixture of a 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and hydroquinone redox pair, p-benzoquinone and its derivatives, tetrafluoro-tetracyanoquinodimethane and its derivatives, a Cu(II) salt, an Fe(III) salt, an Fe(II) salt, a Zn(II) salt, a Mn salt, or any one of them. The solvent of the dopant solution can be any one of acetonitrile, propylene carbonate, and water.

[0069] Furthermore, the molar ratio of the amount of substance of the solute in the dopant solution to the amount of substance of the conjugated polymer in the electrochromic medium is (1 to 1,000,000):1. When the electrochromic film is doped in the dopant solution, the doping time is 30 s to 30 min. Specifically, it should be doped until the optical state of the electrochromic film is stable, that is, the absorption, transmission, or reflection spectrum of the electrochromic film no longer changes, so that the electrochromic film is fully doped.

[0070] In the embodiments of the present invention, the dopant and sulfur on the conjugated polymer molecule form a charge transfer complex (S…[Cu(TFSI) 2– ) through non-covalent interactions, jointly forming an oxidized colorless and transparent electrochromic film and enabling it to exist stably, thereby ensuring that the electrochromic device has high steady-state performance.

[0071] In some alternative embodiments, when the electrochromic medium is made into an electrochromic film by spin coating, specifically, the electrochromic medium can be dropped onto a substrate (such as an ITO glass electrode), and then the substrate is rotated to make the electrochromic medium spread evenly and wait for the solvent to volatilize. The rotation speed of the substrate can be 500 rpm to 5000 rpm, and the spin coating time is 5 s to 5 min.

[0072] In some alternative embodiments, when the electrochromic medium is made into an electrochromic thin film by the doctor blade coating method, specifically, the electrochromic medium can be dropped onto a substrate (such as an ITO glass electrode), and the electrochromic medium is evenly spread by scraping with a doctor blade or a wire bar and waiting for the solvent to volatilize. Among them, the height of the wet film coated by the doctor blade is 5 μm to 500 μm, and the moving speed of the doctor blade or the wire bar is 10 mm / s to 60 mm / s. In addition, in order to reduce the influence of the humidity in the air on the substrate and improve the coating effect, the substrate can be baked under an infrared lamp for 3 min to 10 min before coating.

[0073] As a third aspect, the present invention also provides an electrochromic device. Referring to Figure 3 As shown, the electrochromic device includes a first electrode 1, an electrochromic layer 2, an ion transport layer 3, an ion storage layer 4, and a second electrode 5 which are sequentially stacked. Among them, the material of the electrochromic layer 2 includes the above-mentioned electrochromic thin film.

[0074] Specifically, the materials in the first electrode 1 and the second electrode 5 are any combination of gold, silver, copper, mercury, platinum, palladium, tungsten, aluminum, zinc, zinc oxide, indium oxide and tin oxide composite, tungsten carbide, nickel carbide, graphite, graphene, and carbon nanotube electrode materials.

[0075] The thickness of the ion transport layer 3 is 20 nm to 500 μm. The ion transport layer is specifically any one of a proton transport membrane, a lithium ion conductive membrane, a cation transport membrane, an anion transport membrane, or a gel state or solid medium containing an electrolyte. The ion transport layer is made by the solution casting method using an ion transport medium. The ion transport medium is used for ion transport so as to form an electric conduction loop in the electrochromic device.

[0076] Correspondingly, the ion storage layer 4 is made by the solution casting method using an auxiliary medium. The auxiliary medium is a liquid or solid medium containing an electrolyte. The auxiliary medium is used for charge balance so as to form an electric conduction loop in the electrochromic device. The selection of the electrolyte can refer to any one in the prior art and will not be elaborated here.

[0077] The present invention will be further described below in conjunction with specific embodiments.

[0078] It should be noted that the electrochromic device in the embodiment of the present invention is formed by stacking and encapsulating the first electrode 1, the electrochromic layer 2, the ion transport layer 3, the ion storage layer 4, and the second electrode 5. Among them, the ion transport layer 3 is made of an ion transport medium. The ion transport medium can be specifically prepared by the following method: polymethyl methacrylate (60 wt%), propylene carbonate (25 wt%), and lithium bis(trifluoromethanesulfonyl)imide (15 wt%) are added to acetonitrile and mixed evenly.

[0079] The ion storage layer 4 can be specifically made of an auxiliary medium, and the auxiliary medium is prepared by the following method: adding polymethyl methacrylate (53 wt%), propylene carbonate (22 wt%), lithium bis(trifluoromethanesulfonyl)imide (13 wt%), 1,4-benzoquinone (4.0 wt%) and hydroquinone (8.0 wt%) into acetonitrile and mixing evenly to obtain it.

[0080] Example 1

[0081] (I) Preparation of multi-band electrochromic polymer

[0082] In this example, the preparation process of the multi-band electrochromic polymer includes the following steps:

[0083] Synthesis of BRMA-1 molecule: Add p-bromoaniline (12 g, 70 mmol), sodium hydroxide (2.8 g, 70 mmol), dichloro(pentamethylcyclopentadienyl)iridium(III) dimer (55.8 mg, 0.07 mmol) and methanol (100 mL) into a dry glass pressure-resistant tube. After replacing the gas in the pressure-resistant tube with nitrogen, seal the pressure-resistant tube. Then heat the reaction system to 150 °C and react for 24 h. After the reaction is completely cooled to room temperature, open the pressure-resistant tube, filter and wash the insoluble matter with methanol, and collect the filtrate. Rotavaporize and concentrate the filtrate, and then use column chromatography to separate the product. The eluent is petroleum ether / ethyl acetate to obtain a light yellow oily liquid product with a yield of 85%.

[0084] Synthesis of BRMA-2 molecule: Add 4-bromo-N-methylaniline (2.56 g, 13.8 mmol), sodium bicarbonate (1.16 g, 13.8 mmol) and 2-bromoethanol (4.3 g, 34.5 mmol) into a reaction flask. After replacing the gas in the reaction flask with nitrogen, stir vigorously to disperse the raw materials and the base in 2-bromoethanol. Heat the reaction flask to 60 °C, stir vigorously at the same time, and monitor the progress of the reaction by thin layer chromatography. The reaction time is 36 h. After the reaction is complete, stop the reaction, add dichloromethane and saturated brine, separate the liquid to obtain an organic phase and an inorganic phase, and wash the organic phase with saturated brine twice. Dry the organic phase with anhydrous sodium sulfate, concentrate and then use column chromatography to separate the product. The eluent is petroleum ether / ethyl acetate to obtain a white solid product, the BRMA-2 molecule, with a yield of 90%.

[0085] Synthesis of 1-1 intermediate: Add 3,4-dimethoxythiophene (80 mmol, 1.0 eq), 2,2-dibromoneopentyl glycol (80 mmol, 1.2 eq) and p-toluenesulfonic acid (8 mmol, 0.1 eq) into toluene (100 mL), freeze-pump three times under nitrogen, and then react at 120 °C for 24 h. After the reaction, use column chromatography to separate to obtain 64.0 mmol of 1-1 intermediate with a yield of 80%.

[0086] Synthesis of 1-2 intermediate: 1-1 intermediate (0.25 mmol, 1.0 eq), 2-hexyldecanoic acid (2.6 eq), potassium carbonate (0.75 mmol, 3.0 eq) and N,N-dimethylacetamide (3 mL) were mixed, frozen and evacuated three times under nitrogen, and then reacted at 100 °C for 24 h. The reaction mixture was separated by column chromatography to obtain 1-2 intermediate with a yield of 97%.

[0087] Synthesis of 1-3 intermediate: 1-2 intermediate (1.87 mmol, 1.0 eq) was added to N,N-dimethylacetamide (21 mL), frozen and evacuated twice under nitrogen, then N-bromosuccinimide (4.11 mmol, 2.2 eq) was added. After being frozen and evacuated once more under nitrogen, the reaction was carried out at room temperature for 2 h. The reaction mixture was separated by column chromatography to obtain 1-3 intermediate with a yield of 98%.

[0088] Synthesis of 1-4 intermediate: BRMA-2 molecule (5.0 mmol, 1.0 eq), sodium hydride (15.0 mmol, 3.0 eq) and N,N-dimethylformamide (75 mL) were added to a reaction flask and mixed, frozen and evacuated three times and heated to 70 °C for 24 h. Subsequently, 1-1 intermediate (5.5 mmol, 1.1 eq) was added and the reaction was carried out for 48 h. After the reaction was completed, extraction and washing were carried out successively with methyl tert-butyl ether, saturated brine and saturated sodium bicarbonate solution, and back-extraction was carried out once. Then it was dried and separated by column chromatography to obtain 1-4 intermediate with a yield of 44%.

[0089] Synthesis of 1-5 intermediate: 1-4 intermediate (2.97 mmol, 1.0 eq), 2-hexyldecanoic acid (1.3 eq) and potassium carbonate (8.91 mmol, 3.0 eq) were added to N,N-dimethylacetamide (30 mL), frozen and evacuated three times, heated to 100 °C for 24 h. After the reaction was completed, extraction and washing were carried out with methyl tert-butyl ether and saturated brine, dried, and separated by column chromatography to obtain 1-5 intermediate with a yield of 57%.

[0090] 1-6 intermediate is a rhodamine unit, and the structural formula of the rhodamine unit is:

[0091]

[0092] Synthesis of Intermediate 1-7: Intermediate 1-5 (0.849 mmol, 1.0 eq), Intermediate 1-6 (1.019 mmol, 1.2 eq), cesium carbonate (2.547 mmol, 3.0 eq), palladium acetate (0.0849 mmol, 0.1 eq) and 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl (0.255 mmol, 0.3 eq) were added to 26 mL of toluene. After three freeze-pump-thaw cycles, the temperature was raised to 110 °C and the reaction was carried out for 48 h. After the reaction was completed, it was washed with methyl tert-butyl ether and saturated brine, and back-extracted once. After drying, 0.274 mmol of Intermediate 1-7 was obtained by column chromatography, and the yield was 32%.

[0093] Synthesis of multi-band electrochromic polymer: The prepared Intermediate 1-7 (0.247 mmol, 1.0 eq), Intermediate 1-3 (0.247 mmol, 1.0 eq), potassium carbonate (0.618 mmol, 2.5 eq), palladium acetate (0.005 mmol, 0.02 eq) and pivalic acid (0.074 mmol, 0.3 eq) were added to N,N-dimethylacetamide (2.5 mL). The temperature was slowly raised from 50 °C to 100 °C and the reaction was carried out for 48 h. After the reaction was completed, the solid was precipitated with methanol, washed with a Soxhlet extractor, and the solid was precipitated again with methanol and dried in vacuo to obtain a multi-band electrochromic polymer with a yield of 45%.

[0094] In this example, the structural formula of the prepared multi-band electrochromic polymer is shown in Formula (Ⅰ-1):

[0095]

[0096] In Formula (Ⅰ-1), n is 45, and Formula (Ⅰ-1) is based on the polythiophene backbone unit in Formula Ⅰ and the rhodamine unit in Formula XIII. Among them, R1 and P2 in Formula Ⅰ are 2-hexyldecyl, the rhodamine unit is connected to the P1 position, m = 1 in P1, R3 in Formula XIII is N,N-dibutyl, R5 is methyl, R6 is phenyl, R4, R7, R8 are hydrogen, Y is oxygen, Ar is a benzene ring, and Z1 is methyl.

[0097] (2) Preparation of electrochromic film

[0098] Preparation of electrochromic film based on the multi-band electrochromic polymer in formula (Ⅰ-1): Dissolve 30 mg of the multi-band electrochromic polymer in a mixed solvent of 800 μL of tetrahydrofuran and 200 μL of xylene to obtain an electrochromic medium. Spin-coat the electrochromic medium on the ITO glass electrode to obtain an electrochromic film. Among them, the rotation speed of spin-coating is 1000 rpm and the spin-coating time is 30 s. Then place the electrochromic film in an acetonitrile solution of iron p-toluenesulfonate and let it stand for 10 min until the optical state of the electrochromic film is stable (the absorption, transmission or reflection spectrum of the electrochromic film no longer changes), so that the electrochromic film is fully doped. Among them, the molar ratio of iron p-toluenesulfonate to the multi-band electrochromic polymer is 50000:1.

[0099] Figure 4 is the SEM image of the surface of the electrochromic film in this example. It can be seen from Figure 4 that the surface of the electrochromic film in this example is uniform and dense.

[0100] Figure 5 is the cross-sectional SEM image of the electrochromic film in this example. It can be seen from Figure 5 that the thickness of the electrochromic film in this example is about 100 nm.

[0101] (III) Assembly of electrochromic device

[0102] Spin-coat the electrochromic medium on the first electrode, and the first electrode is specifically an ITO glass electrode, to obtain an electrochromic film. After further doping the electrochromic film, assemble it with the ion transport layer, ion storage layer and the second electrode in sequence and encapsulate to obtain an electrochromic device.

[0103] Figure 6 is the ultraviolet-visible-near-infrared absorption spectrum of the electrochromic device. In the initial state of the electrochromic device in this example, it is colorless in the visible light region and has absorption in the near-infrared region; after applying a negative voltage of -1.0 V, the optical signal changes, the absorption in the near-infrared region decreases, and it shows purplish red in the visible light region. After applying a positive voltage of +0.4 V, the spectrum of the device returns to the initial state. After applying a positive voltage of +2.0 V, the absorption in the near-infrared region increases and it shows dark green in the visible light region. After applying a positive voltage of +0.4 V, the device can also return to the initial state, demonstrating good electrochromic reversibility.

[0104] Figure 7 is the response speed characterization diagram of the electrochromic device. It can be seen from Figure 7 that the coloring time of the electrochromic device is 142 ms and the fading time is 152 ms, which indicates that the electrochromic device shows excellent response speed in the long-spectrum multi-band.

[0105] Figure 8 From top to bottom are the tristable performance diagrams of the electrochromic device after applying voltages of +0.4V, +2.0V, and -1.0V. From Figure 8 it can be seen that the selected absorption wavelength for detection is 580nm. In the state without applying voltage, the information can be maintained for 48 hours, and the optical modulation ability decays by less than 5.7%. When applying a voltage of +2.0V again, the device changes from the colorless state to the colored state again, and the steady state can be maintained for 5 hours, and the optical modulation ability decays by less than 7.0%. When applying a voltage of -1.0V, the device changes from the colorless state to another colored state, and the steady-state information can be maintained for a long time. Therefore, the electrochromic device of this embodiment exhibits good multi-band optical modulation ability ( △ T), showing excellent tristable properties.

[0106] The comparison of the conductivity changes of the electrochromic thin film before and after doping is shown in Table 1. It can be seen from Table 1 that after doping, the conductivity of the electrochromic thin film has a significant increase of 3 orders of magnitude, and the conductivity performance is excellent.

[0107] Table 1 Conductivity changes of electrochromic thin films before and after doping

[0108]

[0109] Example 2

[0110] The preparation of the multi-band electrochromic polymer in this example includes:

[0111] Synthesis of intermediate 2-1: Synthesize intermediate 2-1 according to the synthesis method of BRMA-1 molecule in Example 1.

[0112] Synthesis of intermediate 2-2: Synthesize intermediate 2-2 according to the synthesis method of BRMA-2 molecule in Example 1.

[0113] Synthesis of intermediate 2-3 and intermediate 2-4: Synthesize according to the synthesis method of intermediate 1-4 in Example 1.

[0114] Synthesis of intermediate 2-5: Add 1,4-dibromo-2,5-dimethoxybenzene (10 mmol, 1.0 eq) to intermediate 2-4, purge with argon 3 times, then add 100 mL of anhydrous tetrahydrofuran and stir to cool down to -78 °C. Slowly add n-butyllithium (40 mmol, 4.0 eq.) and then warm up to 0 °C, stir for one hour, cool down to -78 °C again, slowly add isopropyl alcohol pinacol borate (40 mmol, 4.0 eq), warm up to room temperature again, and stir. Quench the reaction with 30 mL of 0.05 mmol hydrochloric acid, extract with ethyl acetate, dry, and recrystallize to obtain white crystal intermediate 2-5 with a yield of 57%.

[0115] The intermediate 2-6 is a rhodamine unit, and the structural formula of the rhodamine unit is:

[0116]

[0117] Synthesis of intermediate 2-7: It was synthesized according to the synthesis method of intermediate 1-7 in Example 1, only replacing the reaction substrates with intermediate 2-5 and intermediate 2-6.

[0118] Synthesis of intermediate 2-8: Dissolve intermediate 2-7 (1.0 eq) in 60 mL of chloroform and purge with argon to remove oxygen. Dissolve N-bromosuccinimide (2.5 eq), deoxygenate with argon, then cool the temperature to 0 °C, and slowly add the chloroform solution of intermediate 2-1 to the N-bromosuccinimide solution, keeping the whole process in the dark. After addition, stir and react at 0 °C. After the reaction is completed, separate by column chromatography to obtain intermediate 2-8 with a yield of 72%.

[0119] Synthesis of the multi-band electrochromic polymer: Add intermediate 2-8 (1.0 eq), methyltrioctylammonium chloride (two drops), molecule 2-5 (1.005 eq), tris(dibenzylideneacetone)dipalladium(0) (0.01 eq), tris(o-tolyl)phosphine (0.03 eq), and cesium fluoride (25.0 eq.) to 15 mL of anhydrous toluene, freeze-pump three times, heat up to 90 °C, and react in the dark for 24 h. After the reaction is completed, precipitate the solid with methanol, wash it successively with methanol, hexane, and chloroform using a Soxhlet extractor, then concentrate the obtained solution, add diethylammonium diethyldithiocarbamate and stir, and then precipitate it into methanol and dry it under vacuum to obtain the electrochromic polymer with a yield of 36%.

[0120] In this example, the structural formula of the prepared multi-band electrochromic polymer is shown as formula (II-1):

[0121]

[0122] In this example, n in formula (II-1) is 143, and the structural formula of the molecule of formula (II-1) is based on the polythiophene backbone unit in formula I and the rhodamine unit in formula XII. Among them, P2 in formula I is 2-ethylhexoxy, the rhodamine unit is connected to the P1 position, m = 2 in P1, R3 in formula XII is N,N-dibutyl, R5 is methyl, R6 is phenyl, R4, R7, R8 are hydrogen, Y is oxygen, Ar1 is a benzene ring substituted with p-methoxy, and Z1 is ethyl.

[0123] The multi-band electrochromic polymer in this example was used to prepare an electrochromic medium by the same method as in Example 1. The polymer concentration was 5 mg / mL, and the solvent was dichloromethane. The electrochromic medium was scrape-coated on an ITO glass electrode to obtain an electrochromic film, and the electrochromic film was doped with an acetonitrile solution of iron p-toluenesulfonate. Then it was assembled into an electrochromic device. The initial state was a colorless state. Under the stimulation of a negative voltage, the device changed from a colorless state to a blue state; under the stimulation of different positive voltages, the colored state changed to a purple or colorless state. It exhibited good electrochromic performance.

[0124] Example 3

[0125] The preparation process of the multi-band electrochromic polymer in this example includes:

[0126] Synthesis of intermediate 3-1: Intermediate 3-1 was synthesized according to the synthesis method of the BRMA-2 molecule in Example 1.

[0127] Synthesis of intermediate 3-2: Intermediate 3-2 was synthesized according to the synthesis method of intermediate 1-4 in Example 1.

[0128] Synthesis of intermediate 3-3: Intermediate 3-3 was synthesized according to the synthesis method of intermediate 1-5 in Example 1, where 2-hexyldecanoic acid in Example 1 was replaced with 2-butyldodecanoic acid.

[0129] Intermediate 3-4 is a rhodamine unit, and the structural formula of the rhodamine unit is:

[0130]

[0131] Synthesis of intermediate 3-5: Intermediate 3-5 was synthesized according to the synthesis method of intermediate 1-7 in Example 1, and only the reaction substrates were replaced with intermediate 3-3 and intermediate 3-4.

[0132] Synthesis of intermediate 3-6: Intermediate 3-5 molecules (1.0 eq) and 3,3-dimethyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin (1.0 eq) were added to 300 mL of anhydrous tetrahydrofuran. Argon was introduced for 30 minutes to remove oxygen, the temperature was lowered to -78 °C, n-butyllithium (1.0 eq) was added, stirred, and heated to room temperature. The resulting solution was added to a tetrahydrofuran solution (80 mL) of anhydrous iron(III) acetylacetonate (1.0 eq). Argon was introduced and the reaction was carried out at room temperature for a period of time. After completion, intermediate 3-6 was obtained by column chromatography separation with a yield of 80%.

[0133] Synthesis of the multi-band electrochromic polymer: It was synthesized according to the synthesis method of intermediate 1-3 in Example 1.

[0134] In this embodiment, the structural formula of the prepared multi-band electrochromic polymer is shown in Formula III-1:

[0135]

[0136] In this embodiment, n in Formula (III-1) is 14. The structural formula of the molecule of Formula (III-1) is based on the polythiophene backbone unit in Formula III and the rhodamine unit in Formula XIII. Among them, R1 in Formula III is hydrogen, P2 is 2-butyl dodecyl, the rhodamine unit is connected to the P1 position, m in P1 is 1, R3 and R4 in Formula XIII are connected to form a piperidine ring, R5 and R6 are connected to form a piperidine ring, R7 and R8 are hydrogen, Y is Si(CH3)2, Ar1 is a naphthalene ring, and Z1 is a methyl group.

[0137] The multi-band electrochromic polymer in this embodiment is used to prepare an electrochromic medium by the same method as in Example 1. The polymer concentration is 20 mg / mL, and the solvent is tetrahydrofuran. The electrochromic medium is spin-coated on an ITO glass electrode to obtain an electrochromic film, and the electrochromic film is doped with propylene carbonate of copper(II) chloride. Then it is assembled into an electrochromic device. The initial state of the electrochromic device is colorless. Under the stimulation of a negative voltage, the device changes from a colorless state to a pink color; under different positive voltages, the colored state changes back to a red or colorless state. It exhibits good electrochromic performance.

[0138] Example 4

[0139] In this embodiment, the synthesis process of the multi-band electrochromic polymer is as Figure 9 shown.

[0140] In this embodiment, the structural formula of the prepared multi-band electrochromic polymer is shown in Formula IV-1:

[0141]

[0142] In this embodiment, x in Formula (IV-1) is 9, y is 11, n is 16. The structural formula in Formula (IV-1) is based on the polythiophene backbone unit in Formula IV and the rhodamine unit in Formula XIII. Among them, the rhodamine unit is connected to the P1 position, m in P1 is 2, P2 in Formula IV is 2-propyl hexyl, Ar1 is a benzene ring substituted with a para-methoxy group, Ar2 is a benzene ring, R3 and R5 in Formula XIII are methoxy groups, R4, R6, and R7 are hydrogen, R8 is a methyl group, Y is O, Ar3 is a benzene ring, and Z1 is an ethyl group.

[0143] The multi - band electrochromic polymer in this example was prepared into an electrochromic medium by the same method as in Example 1. The polymer concentration was 40 mg / mL, and the solvent was tetrahydrofuran. The electrochromic medium was spin - coated on an ITO glass electrode to obtain an electrochromic film, and the electrochromic film was doped with an acetonitrile solution of iron(III) chloride. Then it was assembled into an electrochromic device. The initial state of the electrochromic device was a colorless state. Under the stimulation of different negative voltages, the device changed from a colorless state to an orange color; under different positive voltages, the colored state changed back to a yellow or colorless state, showing good electrochromic performance.

[0144] Example 5

[0145] The preparation process of the multi - band electrochromic polymer in this example includes:

[0146] Synthesis of intermediate 5 - 1: Intermediate 5 - 1 was synthesized according to the synthesis method of intermediate 1 - 3 in Example 1.

[0147] Synthesis of intermediate 5 - 2: Intermediate 5 - 2 was synthesized according to the synthesis method of intermediate 1 - 4 in Example 1, where 2 - ethylhexanol was replaced by 2 - octyldodecanoic acid.

[0148] Intermediate 5 - 3 is a rhodamine unit, and the structural formula of the rhodamine unit is:

[0149]

[0150] Synthesis of intermediate 5 - 4: Intermediate 5 - 4 was synthesized according to the synthesis method of intermediate 1 - 7 in Example 1, only replacing the reaction substrates with intermediate 5 - 2 and intermediate 5 - 3.

[0151] Synthesis of intermediate 5 - 5: Lithium diisopropylamide (3.0 eq) was added to 50 mL of diethyl ether in an ice - water bath at 0 °C, and intermediate 5 - 4 molecules (1.0 eq) were slowly added. Then the mixture was stirred at room temperature, cooled to 0 °C again, tributyltin chloride (3.0 eq) was added and stirred. The reaction solution was diluted with 100 mL of diethyl ether, the organic phase was washed with water and dried, and intermediate 5 - 5 was obtained by column chromatography with a yield of 90%.

[0152] Synthesis of multi-band electrochromic polymer: The obtained 5-5 intermediate (1.0 eq), 5-1 intermediate (0.75 eq), 4,7-dibromo-2,1,3-benzothiadiazole (0.25 eq), tris(dibenzylideneacetone)dipalladium (0.02 eq) and tris(o-tolyl)phosphine (0.08 eq) were added to 20 mL of toluene, and freeze-pumped three times, then reacted at 100 °C for 48 h. After the reaction was completed, it was precipitated into 300 mL of methanol, filtered, and then extracted successively with methanol, hexane, and chloroform using a Soxhlet extractor. After extraction, it was redeposited into methanol to obtain the multi-band electrochromic polymer with a yield of 69%.

[0153] In this example, the structural formula of the prepared multi-band electrochromic polymer is shown in Formula V-1:

[0154]

[0155] In this example, x in Formula (V-1) is 15, y is 31, and n is 10. The structural formula of the molecule of Formula V-1 is based on the polythiophene backbone unit in Formula V and the rhodamine unit in Formula XII. Among them, the rhodamine unit is connected at the P1 position, m = 1 in P1, P2 is 2-octyldodecyloxy, Ar1 is 2,1,3-benzothiadiazole, R1 in Formula V is hydrogen, R3 and R5 in Formula XII are methoxy, R4 is anilino, R6, R7, and R8 are hydrogen, Ar3 is a benzene ring, and Z1 is methyl.

[0156] The electrochromic medium was prepared from the multi-band electrochromic polymer in this example by the same method as in Example 1. The polymer concentration was 50 mg / mL, and the solvent was tetrahydrofuran and xylene (volume ratio 5:1). The electrochromic medium was spin-coated on an ITO glass electrode to obtain an electrochromic film, and the electrochromic film was doped with an acetonitrile solution of copper(II) bis(trifluoromethanesulfonyl)imide. Then it was assembled into an electrochromic device. The initial state of the electrochromic device was a colorless state. Under the stimulation of a negative voltage, the device changed from a colorless state to a black state; under different positive voltages, the colored state changed to a yellow or colorless state. It exhibited good electrochromic performance.

[0157] Example 6

[0158] The preparation process of the multi-band electrochromic polymer in this example includes:

[0159] Synthesis of 6-1 intermediate: The 6-1 intermediate was synthesized according to the synthesis method of the 1-4 intermediate, where 2-hexyldecanoic acid was replaced by 2-propylheptanoic acid.

[0160] The 6-2 intermediate is a rhodamine unit, and the structural formula of the rhodamine unit is:

[0161]

[0162] Synthesis of Intermediate 6-3: Intermediate 6-1 was synthesized according to the synthesis method of Intermediate 1-7, with only the reaction substrates replaced by Intermediate 6-1 and Intermediate 6-2.

[0163] Synthesis of Intermediate 6-4: Intermediate 6-4 was synthesized according to the synthesis method of Intermediate 1-3.

[0164] Synthesis of Intermediate 6-5: Intermediate 6-1 was synthesized according to the synthesis method of Intermediate 1-4, where 2-hexyldecanoic acid was replaced by 2-propylheptanoic acid.

[0165] Synthesis of Intermediate 6-6: Intermediate 6-6 was synthesized according to the synthesis method of Intermediate 1-3.

[0166] Synthesis of multi-band electrochromic polymer: Palladium acetate (0.01 mmol, 0.02 eq), potassium carbonate (1.3 mmol, 2.6 eq), pivalic acid (0.15 mmol, 0.3 eq) and 4,7-dibromo-2,1,3-benzothiadiazole (0.5 mmol, 1.0 eq) were added to an anhydrous reaction flask, evacuated and purged with argon three times, and the oxygen was removed by blowing with argon; Intermediate 6-3 (1 eq), Intermediate 6-4 (1 eq), Intermediate 6-5 (1 eq), and Intermediate 6-6 (1 eq) were added to a vial, and after adding N-methylpyrrolidone (2 mL) to the vial, the oxygen was removed by blowing with argon. The deoxygenated Intermediate 6-2 and N-methylpyrrolidone were added to the reaction flask using a syringe, and the vial was washed twice with 2 mL of N-methylpyrrolidone, and the washing solutions were added to the reaction flask. The reaction flask was heated to 140 °C for reaction. After the reaction was completed, it was cooled to room temperature, added to a mixture of methanol and hydrochloric acid solution and stirred vigorously. The resulting precipitate was filtered, washed with water and methanol, dried, added to chlorobenzene and heated to 60 °C. After complete dissolution, diethylammonium diethyldithiocarbamate (2 mg) and 18-crown-6 (5.0 mmol) were added to the mixture and stirred. After completion, it was precipitated in methanol, and the solid was washed with methanol and dried under vacuum to obtain polymer powder with a yield of 72%.

[0167] In this example, the structural formula of the prepared multi-band electrochromic polymer is shown in Formula VI-1:

[0168]

[0169] In this embodiment, x in formula (VI-1) is 7, y is 26, n is 13, and formula (VI-1) is based on the polythiophene backbone unit in formula VI and the rhodamine unit in formula XIII. Among them, R1 and P2 in formula VI are 2-propylheptyloxy, the rhodamine unit is connected to the P1 position, m in P1 is 1, Ar1 is 2,1,3-benzothiadiazole, R3 in formula XIII is N,N-diethyl, R5 is methyl, R4, R7, R8 are hydrogen, R6 is anilino, Y is O, Ar3 is a benzene ring, and Z1 is methyl.

[0170] The multi-band electrochromic polymer in this embodiment is used to prepare an electrochromic medium by the same method as in Example 1. The polymer concentration is 30 mg / mL, and the solvent is tetrahydrofuran and anisole (volume ratio 4:1). The electrochromic medium is spin-coated on an ITO glass electrode to obtain an electrochromic film, and the electrochromic film is doped with an acetonitrile solution of copper(II) perchlorate. Then it is assembled into an electrochromic device. The initial state of the electrochromic device is a colorless state. Under the stimulation of a negative voltage, the device changes from a colorless state to black; under different positive voltages, the black changes to a wine-red or colorless state, showing good electrochromic performance.

[0171] Example 7

[0172] In this embodiment, the synthesis process of the multi-band electrochromic polymer is as Figure 10 shown.

[0173] In this embodiment, the structural formula of the prepared multi-band electrochromic polymer is as shown in formula VII-1:

[0174]

[0175] In this embodiment, n in formula (VI-1) is 56, and the structural formula of the molecule of formula VII-1 is based on the polythiophene backbone unit in formula VII and the rhodamine unit in formula XIII. Among them, R1 in formula VII is methyl, P2 is 2-butyl octyl ester group, the rhodamine unit is connected to the P1 position, m in P1 is 2, Ar1 is 2,1,3-benzothiadiazole; in formula XIII, R3 and R5 are 4,4”-dimethyl diphenylamine group, R4, R6, R7, R8 are hydrogen, Y is O, Ar3 is a benzene ring, and Z1 is methyl.

[0176] The multi-band electrochromic polymer in this example was used to prepare an electrochromic medium in the same way as in Example 1. The polymer concentration was 5 mg / mL, and the solvent was tetrahydrofuran and anisole (volume ratio 4:1). The electrochromic medium was spin-coated on an ITO glass electrode to obtain an electrochromic thin film, and the electrochromic thin film was doped with a propylene carbonate solution of copper(II) chloride. Then it was assembled into an electrochromic device. The initial state of the electrochromic device was a colorless state. Under the stimulation of a negative voltage, the device changed from a colorless state to a cyan state; under different positive voltages, the cyan state changed to a blue or colorless state, showing good electrochromic performance.

[0177] Example 8

[0178] The synthesis process of the multi-band electrochromic polymer in this example is as Figure 11 shown.

[0179] In this example, the structural formula of the prepared multi-band electrochromic polymer is as shown in Formula (VIII-1):

[0180]

[0181] In this example, n in Formula (VIII-1) is 27, and the structural formula of the molecule of Formula (VIII-1) is based on the polythiophene backbone unit in Formula VIII and the rhodamine unit in Formula XIII. Among them, R9 and P2 in Formula VIII are 2-propylhexyl groups, the rhodamine unit is connected at the P1 position, m = 2 in P1, R1 is hydrogen, R2 is methyl, and Ar1 is 2,1,3-benzothiadiazole; in Formula XIII, R3 and R5 are N,N-diethyl, R4, R6, R7, and R8 are hydrogen, Y is O, Ar3 is a benzene ring, and Z1 is methyl.

[0182] The multi-band electrochromic polymer in this example was used to prepare an electrochromic medium in the same way as in Example 1. The electrochromic medium was spin-coated on an ITO glass electrode to obtain an electrochromic thin film, and the electrochromic thin film was doped with a propylene carbonate solution of copper(II) chloride. Then it was assembled into an electrochromic device. The initial state of the electrochromic device was a colorless state. Under the stimulation of a negative voltage, the device changed from a colorless state to a green state; under a positive voltage, the colored state changed to a pink or colorless state, showing good electrochromic performance.

[0183] Example 9

[0184] The synthesis process of the multi-band electrochromic polymer in this example is as Figure 12 shown.

[0185] In this example, the structural formula of the prepared multi-band electrochromic polymer is as shown in Formula (IX-1):

[0186]

[0187] In this embodiment, n in formula (IX-1) is 17, and the structural formula of the molecule of formula (IX-1) is based on the polythiophene backbone unit in formula IX and the rhodamine unit in formula XIII. Among them, R1 and R9 in formula IX are 2-propylheptyl, R2 and P2 are 2-ethylhexyl, the rhodamine unit is connected to the P1 position, m in P1 is 1, and Ar1 is 2,1,3-benzothiadiazole; R3 and R5 in formula XIII are methoxy, R4, R6, R7, and R8 are hydrogen, Y is O, Ar3 is a benzene ring, and Z1 is methyl.

[0188] The multi-band electrochromic polymer in this embodiment is used to prepare an electrochromic medium in the same method as in Example 1. The polymer concentration is 10 mg / mL, and the solvent is tetrahydrofuran and chlorobenzene (volume ratio 7:1). The electrochromic medium is spin-coated on an ITO glass electrode to obtain an electrochromic film, and the electrochromic film is doped with an acetonitrile solution of copper(II) chloride. Then it is assembled into an electrochromic device. The initial state of the electrochromic device is a colorless state. Under the stimulation of a negative voltage, the device changes from a colorless state to green; under a positive voltage, the colored state changes back to yellow or a colorless state, showing good electrochromic performance.

[0189] Example 10

[0190] In this embodiment, the synthesis process of the multi-band electrochromic polymer is as Figure 13 shown.

[0191] In this embodiment, the structural formula of the prepared multi-band electrochromic polymer is as shown in formula (X-1):

[0192]

[0193] In this embodiment, n in formula (X-1) is 13, and the structural formula of the molecule of formula (X-1) is based on the polythiophene backbone unit in formula X and the rhodamine unit in formula XIII. Among them, R1 in formula X is hydrogen, R2 and P2 are 2-ethylhexyl, the rhodamine unit is connected to the P1 position, m in P1 is 2, and Ar1 is 2,1,3-benzothiadiazole; R3 in formula XIII is N,N-dibutyl, R5 is methyl, R6 is anilino, R4, R7, and R8 are hydrogen, Y is O, Ar3 is a benzene ring, and Z1 is methyl.

[0194] The multi-band electrochromic polymer in this example was used to prepare an electrochromic medium in the same method as in Example 1. The polymer concentration was 40 mg / mL, and the solvent was tetrahydrofuran and dichloromethane (volume ratio 1:1). The electrochromic medium was spin-coated on an ITO glass electrode to obtain an electrochromic thin film, and the electrochromic thin film was doped with an acetonitrile solution of copper(II) chloride. Then it was assembled into an electrochromic device. The initial state of the electrochromic device was a colorless state. Under the stimulation of a negative voltage, the device changed from a colorless state to green; under a positive voltage, the colored state changed back to cyan or colorless state, showing good electrochromic performance.

[0195] Example 11

[0196] The synthesis process of the multi-band electrochromic polymer in this example is as Figure 14 shown.

[0197] In this example, the structural formula of the prepared multi-band electrochromic polymer is as shown in Formula (XI-1):

[0198]

[0199] In this example, n in Formula (XI-1) is 10. The structural formula of the molecule of Formula (XI-1) is based on the polythiophene backbone unit in Formula XI and the rhodamine unit in Formula XIII. Among them, R1 and R2 in Formula XI are methyl, P2 is 2-ethylhexyloxy, the rhodamine unit is connected at the P1 position, m in P1 is 2, Ar1 is 2,1,3-benzothiadiazole; R3 and R5 in Formula XIII are 4,4'-dimethyl diphenylamino, R4, R6, R7, and R8 are hydrogen, Y is O, Ar3 is a benzene ring, and Z1 is methyl.

[0200] The multi-band electrochromic polymer in this example was used to prepare an electrochromic medium in the same method as in Example 1. The polymer concentration was 20 mg / mL, and the solvent was tetrahydrofuran. The electrochromic medium was scrape-coated on an ITO glass electrode to obtain an electrochromic thin film, and the electrochromic thin film was doped with an acetonitrile solution of copper(II) chloride. Then it was assembled into an electrochromic device. The initial state of the electrochromic device was a colorless state. Under the stimulation of a negative voltage, the device changed from a colorless state to green; under a positive voltage, the colored state changed back to blue or colorless state, showing good electrochromic performance.

[0201] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will all fall within the protection scope of the present invention.

Claims

1. A multi-band electrochromic polymer, characterized in that, The structural formula of the multi-band electrochromic polymer is any one of Formula I to Formula XI: In Formula I to Formula XI, n is from 1 to 200, x is from 1 to 50, and y is from 1 to 50; The structural formula of P1 and / or P2 is wherein m is from 1 to 24, and the structural formula of B is any one of Formula XII, Formula XIII, or a structural formula obtained by connecting at least two groups among R3, R4, R5, R6, R7, and R8 of Formula XII and Formula XIII respectively: In Formulas I to XIII, R1, R2, R3, R4, R5, R6, R7, R8, and R9 are each independently H, halogen, hydroxyl, amino, C1-C 24 alkyl, C1-C 24 alkyloxy, C1-C 24 substituted alkyloxy, C1-C 24 ester group, C1-C 24 substituted alkyl ester group, C1-C 24 alkylamino, and C6-C 24 aryl, any one of them; Y is any one of an O atom, an S atom, and Si(CH3)2; Z1 is any one of H, an alkyl group having 1 to 24 carbons, a substituted alkyl group having 1 to 24 carbons, an acyl group having 1 to 24 carbons, an alkoxy group having 1 to 24 carbons, and an aryl group having 6 to 24 carbons; Ar1, Ar2, and Ar3 are each an aromatic ring or substituted aromatic ring having from 6 to C 12 aromatic rings.

2. An electrochromic thin film, characterized in that, The material of the electrochromic thin film includes the multi-band electrochromic polymer described in Claim 1.

3. The electrochromic film according to claim 2, wherein The thickness of the electrochromic thin film is from 50 nm to 50 μm.

4. A method for preparing an electrochromic film, which is used to prepare the electrochromic film according to claim 2 or 3, and is characterized in that, Including: Disperse the multi-band electrochromic polymer in an organic solvent to obtain an electrochromic medium, and use a spin coating method to form the electrochromic medium into an electrochromic thin film; Place the electrochromic thin film in a dopant solution for doping to obtain a final electrochromic thin film.

5. The method for preparing an electrochromic thin film according to claim 4, characterized in that, The solute of the dopant solution is any one of a mixture of benzoquinone and hydroquinone redox pairs, a mixture of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and hydroquinone redox pairs, benzoquinone and its derivatives, tetrafluorotetracyanoquinodimethane and its derivatives, Cu(II) salts, Fe(III) salts, Fe(II) salts, Zn(II) salts, Mn salts and other variable-valence metal salts; the solvent of the dopant solution is any one of acetonitrile, water, or propylene carbonate.

6. The preparation method of the electrochromic film according to claim 4, characterized in that, The molar ratio of the solute in the dopant solution to the multi-band electrochromic polymer in the electrochromic medium is (1 to 1,000,000):

1.

7. The method for preparing an electrochromic thin film according to claim 4, characterized in that, When using the spin coating method to form the electrochromic medium into an electrochromic thin film, it includes: Drop the electrochromic medium onto the substrate, and then rotate the substrate to make the electrochromic medium spread evenly. Among them, the rotation speed of the substrate is from 500 rpm to 5000 rpm, and the spin coating time is from 5 s to 5 min.

8. The preparation method of the electrochromic thin film according to claim 4, characterized in that, When using the blade coating method to form the electrochromic medium into an electrochromic thin film, it includes: Drop the electrochromic medium onto the substrate, and then use a blade or a wire bar to scrape the electrochromic medium until it spreads evenly. Among them, the height of the wet film for scraping is from 5 μm to 500 μm, and the moving speed of the blade or the wire bar is from 10 mm / s to 60 mm / s.

9. The preparation method of the electrochromic film according to claim 4, characterized in that, When placing the electrochromic thin film in the dopant solution for doping, the doping time is from 30 s to 30 min.

10. An electrochromic device, the electrochromic device comprising a first electrode, an electrochromic layer, an ion transport layer, an ion storage layer, and a second electrode that are sequentially stacked, characterized in that, The electrochromic layer includes the electrochromic thin film described in Claim 2 or 3.

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