Electrochromic film, electrochromic device and preparation method thereof

Abstract

The invention provides an electrochromic film, an electrochromic device and a preparation method of the electrochromic film, and relates to the technical field of electrochromic materials.The preparation method of the electrochromic film comprises the steps that a conjugated polymer is dissolved in a good 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; the electrochromic film is placed in a dopant solution to be doped, and the final electrochromic film is obtained. The invention provides a novel color changing mode of the polythiophene-based electrochromic film, and can improve the problem of poor bistable performance of the existing polythiophene-based electrochromic film.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochromic materials, and in particular, to an electrochromic thin film, an electrochromic device and a preparation method thereof. Background Art

[0002] Electrochromism refers to a 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, thereby causing a reversible change in the optical properties (such as absorbance, transmittance, or reflectance) of the material. Polythiophene is a class of conjugated polymer molecules with excellent charge transport properties, and the carriers are holes. It also has electrochromic properties. Based on the electrochromic device of polythiophene, under the stimulation of an external electric field, through the "doping" and "dedoping" mechanisms of electrical regulation, stable electrochromism can be achieved.

[0003] Generally speaking, the polythiophene electrochromic thin film is in a colored state in the intrinsic state and shows colorless in the oxidized state. This makes the prepared electrochromic device have a color in the initial state. Under electrical stimulation, the polythiophene electrochromic device presents a reversible color change mode of "coloring - colorless", which greatly limits the further application of such electrochromic materials and electrochromic devices. Moreover, the bistable performance (memory effect) of traditional polythiophene electrochromic thin films and devices is poor. After removing the voltage stimulation for a period of time, the optical modulation maintenance rate is low and the optical signal decays quickly. Summary of the Invention

[0004] The present invention aims to provide a new color change mode for electrochromic thin films based on polythiophene and to improve the problem of poor bistable performance of current electrochromic thin films based on polythiophene.

[0005] To solve the above problems, the present invention provides an electrochromic thin film, an electrochromic device and a preparation method thereof.

[0006] In a first aspect, the present invention provides a preparation method of an electrochromic thin film, including:

[0007] Disperse a conjugated polymer in a poor solvent to obtain an electrochromic medium, and use a spin coating method or a doctor blade method to form the electrochromic medium into an electrochromic thin film;

[0008] Place the electrochromic thin film in a dopant solution for doping to obtain the final electrochromic thin film;

[0009] The conjugated polymer is selected from

[0010]

[0011] any one of;

[0012] Among them, n ranges from 1 to 200, x ranges from 1 to 50, and y ranges from 1 to 50;

[0013] R 1 、R 2 、R 3 、R 4 are respectively any one of H, halogen, hydroxyl, amino, C 1 to C 24 alkyl between, C 1 to C 24 alkyloxy between, C 1 to C 24 substituted alkyloxy between, C 1 to C 24 ester group between, C 1 to C 24 substituted alkyl ester group between, C 1 to C 24 alkylamino between and C 6 to C 24 any one of aryl between;

[0014] Ar, Ar 1 、Ar 2 are respectively C 6 to C 12 aromatic ring or substituted aromatic ring between, where the aromatic ring is any one of benzene, naphthalene, anthracene, phenanthrene, fluorene, pyrene, perylene, fluoranthene, tetracene, pentacene, 2,1,3-benzothiadiazole, carbazole and benzimidazole;

[0015] The solute in the dopant solution is a mixture of a p-benzoquinone and hydroquinone redox pair, a mixture of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and hydroquinone redox pair, or any one of p-benzoquinone and its derivatives, tetrafluorotetracyanoquinodimethane and its derivatives, Cu(II) salts, Fe(III) salts, Fe(II) salts, Zn(II) salts, Mn salts; the solvent in the dopant solution is any one of acetonitrile, water and propylene carbonate.

[0016] Optionally, the poor solvent is any one or more of tetrahydrofuran, n-hexane, chlorobenzene, xylene, γ-butyrolactone, dichloromethane, ethyl acetate, anisole, etc., and the concentration of the conjugated polymer in the poor solvent is 1 mg / mL to 50 mg / mL.

[0017] Optionally, the molar ratio of the solute in the dopant solution to the conjugated polymer in the electrochromic medium is (1 to 1,000,000):1.

[0018] Optionally, when doping the electrochromic film in the dopant solution, the doping time is 30 s to 30 min.

[0019] Optionally, when the electrochromic medium is made into an electrochromic film by spin coating, it includes:

[0020] Drop the electrochromic medium onto the substrate, and then rotate the substrate to make the electrochromic medium spread evenly, wherein the rotation speed of the substrate is 500 rpm to 5000 rpm, and the spin coating time is 5 s to 5 min.

[0021] Optionally, when the electrochromic medium is made into an electrochromic film by blade coating, it includes:

[0022] 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, wherein 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.

[0023] Optionally, the conjugated polymer is selected from

[0024]

[0025]

[0026] any one of them; wherein, x is from 1 to 50, y is from 1 to 50, and n is from 1 to 200.

[0027] In a second aspect, the present invention relates to an electrochromic film, and the electrochromic film is prepared by the above preparation method.

[0028] Optionally, the thickness of the electrochromic film is 50 nm to 50 μm.

[0029] In a third aspect, the present invention relates to an electrochromic device, and the electrochromic device includes a first electrode, an electrochromic layer, an ion transport layer, an ion storage layer, and a second electrode which are sequentially stacked, and the electrochromic layer includes the above electrochromic film.

[0030] The beneficial effects of the present invention compared with the prior art are:

[0031] The present invention dopes a thin film formed by a conjugated polymer with a dopant to obtain an electrochromic thin film with high transmittance. Through the synergistic effect of charge transfer reaction and the embedding of charge-balanced ions between the conjugated polymer and the dopant, the dopant forms a charge transfer complex (S...M) with sulfur on the conjugated polymer molecules through non-covalent interaction, jointly enabling the stable existence of the electrochromic thin film with high transmittance and ensuring its high bistable performance. Under electrical regulation, reversible changes in the conjugated structure occur through the injection and extraction of charge-balanced substances and electrons, showing a reversible transformation between the oxidized colorless state and the neutral colored state. Specifically, after assembling the electrochromic thin film of the present invention into an electrochromic device, the device is colorless in the initial state. Under the action of an external electric field, the conjugated polymer is reduced, and the non-covalent interaction between the charge transfer complexes is destroyed, showing a colored state; under the stimulation of a reverse voltage, the conjugated polymer is oxidized, and the non-covalent interaction is restored, showing a colorless state. Different degrees of conjugation result in different colors of change, thus realizing the reversible color change mode of "colorless - colored" for the electrochromic device. Moreover, the present invention is beneficial to improving the bistable performance of the electrochromic device, enabling the electrochromic device to have higher coloring efficiency, fading efficiency, and longer bistable retention time. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a process flow chart for the synthesis of the conjugated polymer in Example 1 of the present invention;

[0033] Figure 2 It is an SEM image of the electrochromic thin film before doping in Example 1 of the present invention;

[0034] Figure 3 It is an SEM image of the electrochromic thin film after doping in Example 1 of the present invention

[0035] Figure 4 It is a cross-sectional SEM image of the electrochromic thin film in Example 1 of the present invention;

[0036] Figure 5 It is for the electrochromic thin film in Example 1 of the present invention after Cu 2+ S2p XPS spectra before and after doping;

[0037] Figure 6 It is for the electrochromic thin film in Example 1 of the present invention after Cu 2+ Cu 2p XPS spectra before and after Cu ion doping

[0038] Figure 7 It is for the electrochromic thin film in Example 1 of the present invention after Cu 2+ EDS energy spectrum after Cu ion doping;

[0039] Figure 8Schematic structural diagram of the electrochromic device in Embodiment 1 of the present invention;

[0040] Figure 9 Ultraviolet-visible-near-infrared absorption spectrum of the electrochromic device in Embodiment 1 of the present invention;

[0041] Figure 10 Bistable performance graph of the electrochromic device in the prior art;

[0042] Figure 11 Bistable performance graph of the electrochromic device prepared in Embodiment 1 of the present invention;

[0043] Explanation of reference numerals:

[0044] 1. First electrode; 2. Electrochromic layer; 3. Ion transport layer; 4. Ion storage layer; 5. Second electrode. Detailed implementation manners

[0045] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention will be made with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments described herein. On the contrary, these embodiments are provided to more thoroughly and completely understand the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not used to limit the protection scope of the present invention.

[0046] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those skilled in the technical field to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific implementation manners and are not intended to limit this application;

[0047] As used herein, the term "including" and its variations are open-ended, i.e., "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc. mentioned in the present invention are used to distinguish different objects, rather than to describe a specific order or primary-secondary relationship. In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise specified, "a plurality of" means two or more.

[0048] In view of the problems existing in the related art, the present embodiment provides an electrochromic film, an electrochromic device and a preparation method thereof.

[0049] As a first aspect, the present invention provides a method for preparing an electrochromic film, comprising: dispersing a conjugated polymer in a poor solvent to obtain an electrochromic medium, and forming the electrochromic medium into an electrochromic film by spin coating or blade coating; doping the electrochromic film in a dopant solution to obtain a final electrochromic film.

[0050] Wherein, the conjugated polymer is selected from any one of Formula I to Formula VIII:

[0051]

[0052] Wherein, n is from 1 to 200, x is from 1 to 50, and y is from 1 to 50;

[0053] R 1 、R 2 、R 3 、R 4 are respectively H, halogen, hydroxyl, amino, an alkyl group between C 1 and C 24 , an alkoxy group between C 1 and C 24 , a substituted alkoxy group between C 1 and C 24 , an ester group between C 1 and C 24 , a substituted alkyl ester group between C 1 and C 24 , an alkylamino group between C 1 and C 24 and an alkyl group between C 6 and C24 any one of the aryl groups therebetween;

[0054] Ar, Ar 1 , Ar 2 are respectively aromatic rings or substituted aromatic rings having from C 6 to C 12 wherein the aromatic ring is any one of benzene, naphthalene, anthracene, phenanthrene, fluorene, pyrene, perylene, fluoranthene, tetracene, pentacene, 2,1,3-benzothiadiazole, carbazole, and benzimidazole;

[0055] The solute in the dopant solution is a mixture of a p-benzoquinone and a hydroquinone redox pair, a mixture of a 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and a hydroquinone redox pair, or any one of p-benzoquinone and its derivatives, tetracyanoquinodimethane and its derivatives, Cu(II) salts, Fe(III) salts, Fe(II) salts, Zn(II) salts, and Mn salts.

[0056] The present invention uses a dopant to dope a thin film formed of a conjugated polymer to obtain an electrochromic thin film with a high transmittance. Through the synergistic effects of charge transfer reactions and the insertion of charge-balancing ions between the conjugated polymer and the dopant, a charge transfer complex (S...M) is generated between the dopant and sulfur on the conjugated polymer molecule through non-covalent interactions, jointly enabling the stable existence of the electrochromic thin film with a high transmittance and ensuring its high bistable performance. Under electrical regulation, reversible changes in the conjugated structure occur through the injection and extraction of charge-balancing substances and electrons, showing a reversible transformation between an oxidized colorless state and a neutral colored state. Specifically, after the electrochromic thin film of the present invention is assembled into an electrochromic device, the device is in a colorless state in the initial state. Under the action of an external electric field, the conjugated polymer is reduced, and the non-covalent interaction between the charge transfer complexes is destroyed, showing a colored state; under the stimulation of a reverse voltage, the conjugated polymer is oxidized, and the non-covalent interaction is restored, showing a colorless state. Different degrees of conjugation result in different colors of change, thus realizing the reversible color change mode of "colorless - colored" for the electrochromic device. Moreover, the present invention is beneficial to improving the bistable performance of the electrochromic device, enabling the electrochromic device to have higher coloring efficiency and fading efficiency and a longer bistable retention time.

[0057] In some alternative embodiments, the conjugated polymer may be selected from

[0058]

[0059] any one of them. Wherein, x is from 1 to 50, y is from 1 to 50, and n is from 1 to 200.

[0060] Due to the different degrees of conjugation of conjugated polymers, the colors they exhibit are different. In the embodiments of the present invention, by selecting conjugated polymers with different degrees of conjugation, different color changes and optical signal modulations can be achieved under the stimulation of an external electric field, enabling the corresponding electrochromic devices to have high optical modulation capabilities.

[0061] In some alternative embodiments, by way of example, the solute in the dopant solution can be any one of copper(II) bis(trifluoromethanesulfonyl)imide, copper(II) chloride, copper(II) perchlorate, iron(III) chloride, and iron(III) p-toluenesulfonate, and the solvent is acetonitrile or propylene carbonate. The molar ratio of the solute in the dopant solution to the conjugated polymer in the electrochromic medium is (1 to 1,000,000):1. When doping the electrochromic film in the dopant solution, the doping time is 30 s to 30 min, and 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.

[0062] Taking copper(II) bis(trifluoromethanesulfonyl)imide (Cu(TFSI) 2 ) as a chemical dopant as an example, 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 electrochromic film and enabling it to exist stably, thereby ensuring the high bistable performance of the device.

[0063] In some alternative embodiments, when fabricating the electrochromic film from the electrochromic medium using the spin-coating method, specifically, the electrochromic medium can be dropped onto a substrate (such as an ITO glass electrode), and then the substrate is rotated to evenly spread the electrochromic medium and wait for the solvent to evaporate. The rotation speed of the substrate can be 500 rpm to 5000 rpm, and the spin-coating time is 5 s to 5 min.

[0064] In some alternative embodiments, when fabricating the electrochromic film from the electrochromic medium using 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 doctor-blading or bar-coating and wait for the solvent to evaporate. Among them, the height of the wet film for doctor-blading is 5 μm to 500 μm, and the moving speed of the doctor blade or bar is 10 mm / s to 60 mm / s. In addition, in order to reduce the influence of humidity in the air on the substrate and improve the doctor-blading effect, the substrate can be baked under an infrared lamp for 3 min to 10 min before doctor-blading.

[0065] In some alternative embodiments, the poor solvent can be any one or more of tetrahydrofuran, n-hexane, chlorobenzene, xylene, γ-butyrolactone, dichloromethane, ethyl acetate, anisole, etc. The concentration of the conjugated polymer in the poor solvent can be from 1 mg / mL to 50 mg / mL.

[0066] As a second aspect, the present invention provides an electrochromic film, which is prepared based on the above preparation method. The thickness of the electrochromic film in the embodiments of the present invention is between 50 nm and 50 μm. Preferably, the thickness of the electrochromic film is between 50 nm and 2 μm.

[0067] As a third aspect, the present invention further provides an electrochromic device. 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 that are sequentially stacked, wherein the material of the electrochromic layer 2 includes the above electrochromic film.

[0068] Specifically, the materials of 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 tin oxide composite, tungsten carbide, nickel carbide, graphite, graphene, and carbon nanotube electrode materials.

[0069] The thickness of the ion transport layer 3 is from 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 or solid medium containing an electrolyte. The ion transport layer is made by a solution casting method using an ion transport medium, and the ion transport medium is used for ion transport to form an electric conduction loop in the electrochromic device.

[0070] Correspondingly, the ion storage layer 4 is made by a solution casting method using an auxiliary medium. The auxiliary medium is a liquid or solid medium containing an electrolyte, and the auxiliary medium is used to balance charges 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.

[0071] The present invention will be further described below in conjunction with specific embodiments.

[0072] It should be noted that the electrochromic device in the embodiments 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, and the ion transport medium can be specifically prepared by the following method: adding polymethyl methacrylate (60 wt%), propylene carbonate (25 wt%), and lithium bis(trifluoromethanesulfonyl)imide (15 wt%) to acetonitrile and mixing evenly.

[0073] The ion storage layer 4 can be specifically made of an auxiliary medium, and the auxiliary medium is prepared by the following method: poly(methyl methacrylate) (53 wt%), propylene carbonate (22 wt%), lithium bis(trifluoromethanesulfonyl)imide (13 wt%), 1,4-benzoquinone (4.0 wt%), and hydroquinone (8.0 wt%) are added to acetonitrile and mixed evenly.

[0074] Example 1

[0075] (I) Preparation of conjugated polymer

[0076] Refer to Figure 1 As shown, the preparation process of the conjugated polymer in this example includes the following steps:

[0077] Synthesis of intermediate 1-1: 3,4-Dimethoxythiophene (80 mmol, 1.0 eq), 2,2-bis(bromomethyl)-1,3-propanediol (80 mmol, 1.2 eq), and p-toluenesulfonic acid (8 mmol, 0.1 eq) are added to toluene (100 mL) and mixed evenly. After freezing and pumping three times under nitrogen, the reaction is carried out at 120 °C for 24 h. The reaction mixture is separated by column chromatography to obtain 64 mmol of intermediate 1-1 with a yield of 80%.

[0078] Synthesis of intermediate 1-2: Intermediate 1-1 (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) are mixed. After freezing and pumping three times under nitrogen, the reaction is carried out at 100 °C for 24 h. The reaction mixture is separated by column chromatography to obtain intermediate 1-2 with a yield of 97%.

[0079] Synthesis of intermediate 1-3: Intermediate 1-2 (1.87 mmol, 1.0 eq) is added to N,N-dimethylacetamide (21 mL). After freezing and pumping twice under nitrogen, N-bromosuccinimide (4.11 mmol, 2.2 eq) is added. After freezing and pumping once more under nitrogen, the reaction is carried out at room temperature for 2 h. The reaction mixture is separated by column chromatography to obtain intermediate 1-3 with a yield of 98%.

[0080] Synthesis of conjugated polymer: Under nitrogen, the prepared intermediate 1-2 (0.216 mmol, 1.0 eq), intermediate 1-3 (0.216 mmol, 1.0 eq), potassium carbonate (0.54 mmol, 2.5 eq), palladium acetate (0.0043 mmol, 0.02 eq) and pivalic acid (0.0648 mmol, 0.3 eq) were added to N,N-dimethylacetamide (2.2 mL). Then the reaction system was heated from 50 °C to 100 °C in 30 min and reacted for 48 h. After the reaction was completed, the solid was precipitated with methanol and washed using a Soxhlet extractor. The solvents were methanol, acetone, and n-hexane in sequence. After washing, the remaining solid was precipitated with methanol again, and the precipitated solid was dried under vacuum to obtain the conjugated polymer with a yield of 75%.

[0081] In this example, the structural formula of the prepared conjugated polymer is shown as formula (Ⅰ-1):

[0082]

[0083] In formula (Ⅰ-1), n is 135. The structural formula of the molecule of formula (Ⅰ-1) is based on formula Ⅰ, where R 1 and R 2 are both 2-hexyldecyl groups.

[0084] (II) Preparation of electrochromic film

[0085] Preparation of electrochromic film based on the conjugated polymer in formula (Ⅰ-1): 10 mg of the conjugated polymer was dissolved in a poor solvent of 800 μL of tetrahydrofuran and 200 μL of chlorobenzene to obtain an electrochromic medium. The electrochromic medium was spin-coated on an ITO glass electrode to obtain an electrochromic film. During spin-coating, the rotation speed of the substrate was 1000 rpm and the spin-coating time was 30 s. Then the electrochromic film was placed in an acetonitrile solution of copper(II) bis(trifluoromethanesulfonyl)imide and allowed to stand for 10 min until the optical state of the electrochromic film was stable (the absorption, transmission, or reflection spectrum of the electrochromic film no longer changed), so that the electrochromic film was fully doped. Among them, the molar ratio of copper(II) bis(trifluoromethanesulfonyl)imide to the conjugated polymer in the electrochromic medium is 70000:1.

[0086] Figure 2 is the SEM image of the electrochromic film before doping in this example, Figure 3 is the SEM image of the electrochromic film after doping. As can be seen from Figure 2 and Figure 3 , the surface morphology of the electrochromic film in this example has no obvious change before and after doping, and is relatively uniform and dense.

[0087] Figure 4is the cross-sectional SEM image of the electrochromic thin film of this embodiment. It can be seen from Figure 4 that the thickness of the electrochromic thin film of this embodiment is about 240 nm.

[0088] Figure 5 are the S2p XPS spectra of the electrochromic thin film before and after Cu 2+ doping in this embodiment. Figure 5 Among them, from top to bottom, they respectively represent the S2p XPS spectra of the electrochromic thin film without Cu 2+ doping, the electrochromic thin film doped with Cu 2+ and the electrochromic thin film after Cu 2+ doping and then electrochemical reduction. It can be seen from Figure 5 that compared with the thin film without Cu 2+ doping, the initial peak position of the electrochromic thin film doped with Cu 2+ shifts, and a pair of new peaks appear at 161.7 eV and 160.9 eV, which is caused by the Cu-S coordination bond. At the same time, a pair of new peaks also appear at 166.9 eV and 166.1 eV, which may be the contribution of the "C-S + " bond, jointly indicating that the doping of Cu 2+ to the polymer thin film is effective.

[0089] Figure 6 are the Cu 2p XPS spectra of the electrochromic thin film before and after Cu 2+ ion doping. Figure 6 Among them, from top to bottom, they are respectively the Cu 2p XPS spectra of the electrochromic thin film without Cu 2+ doping, the electrochromic thin film doped with Cu 2+ and the electrochromic thin film after Cu 2+ doping and then electrochemical reduction, which proves the generation of Cu(I) after doping, proves that an electron transfer reaction occurs between the dopant and the polymer molecules, and also confirms the existence of non-covalent interactions in the system. And after applying a negative voltage for reduction, the electrochromic thin film can return to the initial state, showing the reversibility of the electrochemical response of non-covalent interactions.

[0090] Figure 7 is the energy dispersive X-ray spectrometer (EDS) energy spectrum of the electrochromic thin film after Cu 2+ ion doping. It can be seen from Figure 7 that in addition to the Cu element coordinated with S in the doped electrochromic thin film, there is also the doped anion (TFSI -The N and F elements of ( ) prove the existence of the doping anion embedding process. Based on the above experimental data, the synergistic process of charge transfer between the conjugated polymer and the dopant and the embedding of charge-balancing substances is proven. The dopant and sulfur on the conjugated polymer molecule form a charge transfer complex (S…M) through non-covalent interactions.

[0091] (III) Assembly of electrochromic devices

[0092] Refer to Figure 8 As shown, the electrochromic medium is spin-coated on the first electrode, which is specifically an ITO glass electrode, to obtain an electrochromic film. After further doping the electrochromic film, it is assembled with the ion transport layer, ion storage layer, and the second electrode in sequence, and then encapsulated to obtain an electrochromic device.

[0093] Figure 9 is the ultraviolet-visible-near-infrared absorption spectrum of the electrochromic device. From Figure 9 it can be seen that in the initial state, the electrochromic device is colorless and transparent in the visible light region and has absorption in the near-infrared region. After applying a negative voltage of -0.8V for 5s, the optical signal changes, the absorption in the near-infrared region decreases, and the visible light region shows blue-violet. After applying a positive voltage of +0.9V for 5s, the spectrum of the device returns to the initial state, demonstrating good electrochromic reversibility.

[0094] Figure 10 is the bistable performance diagram of the electrochromic device in the prior art, Figure 11 is the bistable performance diagram of the electrochromic device prepared in Example 1 of the present invention. As Figure 10 shown, when the electrochromic film is not doped with a chemical dopant and a positive voltage of +0.9V is applied for 10s, after only 1h, the colorless state of the device decays by 37.2%, and the bistable performance is poor. This type of device tends to return to a more stable colored state. And from Figure 11 it can be seen that after the electrochromic film is doped with a chemical dopant and a positive voltage of +0.9V is applied for 10s, the optical signal of the colorless state of the device only decays by 10% after maintaining for 61h. And after applying a reverse voltage of -0.8V for 10s to the device, the device can still return to the colored state. This shows that the electrochromic device prepared based on electro-responsive non-covalent interactions in Example 1 of the present invention exhibits excellent bistable performance.

[0095] The comparison of the conductivity changes of the electrochromic film before and after doping is shown in Table 1. From Table 1, it can be seen that after doping, the conductivity of the electrochromic film has a significant increase of 3 orders of magnitude, and the conductive performance is excellent.

[0096] Table 1 Conductivity changes of the electrochromic film before and after doping

[0097]

[0098]

[0099] Example 2

[0100] The preparation of the conjugated polymer in this example includes:

[0101] Synthesis of Intermediate 2-1: Sodium hydride (5.4 eq) was added to anhydrous N,N-dimethylformamide (300 mL), and the temperature was raised to 40 °C. 2-Ethylhexanol (150 mmol, 3.0 eq) was added, and then the temperature was raised to 70 °C and stirred. Intermediate 1-1 (50 mmol, 1.0 eq) was continuously added and then stirred. After the reaction was completed, the temperature was lowered to room temperature, quenched with saturated brine, and extracted 4 times with deionized water and hexane, dried. The obtained colorless oily liquid was Intermediate 2-1, with a yield of 97%.

[0102] Synthesis of Intermediate 2-2: Intermediate 2-1 (1.0 eq) was dissolved in 60 mL of chloroform, and then argon was introduced to remove oxygen; at the same time, N-bromosuccinimide (2.5 eq) was dissolved, and after deoxygenation with argon, its temperature was lowered to 0 °C. Then the chloroform solution of Intermediate 2-1 was slowly added to the N-bromosuccinimide solution, protected from light throughout the process, and stirred at 0 °C for 3 h. After the reaction was completed, it was separated by column chromatography to obtain Intermediate 2-2, with a yield of 85%.

[0103] Synthesis of Intermediate 2-3: 1,4-Dibromo-2,5-dimethoxybenzene (10 mmol, 1.0 eq) was added to Intermediate 2-2 and purged with argon 3 times, then anhydrous tetrahydrofuran (100 mL) was added and the temperature was lowered to -78 °C with stirring. n-Butyllithium (40 mmol, 4.0 eq) was slowly added, and then the temperature was raised to 0 °C and stirred for one hour. Then it was cooled to -78 °C again, and isopropyl alcohol pinacol borate (40 mmol, 4.0 eq) was slowly added at -78 °C, and then the temperature was raised to room temperature and stirred. Finally, the reaction was quenched with 30 mL of 0.05 mmol hydrochloric acid, then extracted with ethyl acetate, dried, and recrystallized to obtain white crystal Intermediate 2-3 (5.7 mmol), with a yield of 57%.

[0104] Synthesis of conjugated polymer: 2-2 intermediate (1.0 eq), methyltrioctylammonium chloride (two drops), 2-3 intermediate (1.005 eq), tris(dibenzylideneacetone)dipalladium (0.012 mmol, 0.01 eq), tris(o-tolyl)phosphine (0.036 mmol, 0.03 eq), and cesium fluoride (30 mmol, 25.0 eq) were added to 15 mL of anhydrous toluene. The mixture was freeze-pumped three times and then heated to 90 °C and reacted under dark for 24 h. After the reaction was completed, the solid was precipitated with methanol, and then washed successively with methanol, hexane, and chloroform using a Soxhlet extractor. Subsequently, the washed solution was concentrated, and a palladium scavenger, diethyldithiocarbamate diethylamine, was added and stirred. Then it was precipitated into methanol and dried under vacuum to obtain the conjugated polymer with a yield of 38%.

[0105] In this example, the structural formula of the prepared conjugated polymer is shown in Formula (II-1):

[0106]

[0107] In this example, n in Formula (II-1) is 85, and the structural formula of the molecule of Formula (II-1) is based on Formula II, where R in Formula II 1 is 2-ethylhexyloxy, and Ar is a benzene ring substituted with p-methoxy

[0108] The electrochromic medium was prepared from the conjugated polymer in this example in the same manner as in Example 1. In the electrochromic medium, the poor solvents are a mixture of dichloromethane and xylene, and the volume ratio of dichloromethane to xylene is 5:1, and the concentration of the conjugated polymer is 5 mg / mL. Specifically, the ITO glass electrode was baked under an infrared lamp for 5 min, and then the electrochromic medium was spin-coated onto the ITO glass electrode until evenly spread and allowed the solvent to evaporate to obtain an electrochromic film. Among them, the height of the wet film for spin-coating is 250 μm, and the moving speed of the doctor blade or wire bar is 30 mm / s. Finally, the electrochromic film was doped in a propylene carbonate solution of copper(II) bis(trifluoromethanesulfonyl)imide, and the molar ratio of copper(II) bis(trifluoromethanesulfonyl)imide to the conjugated polymer in the electrochromic medium is 50000:1. Then it was assembled into an electrochromic device. The electrochromic device in this example was colorless in the initial state, and under the stimulation of a negative voltage, the device changed from colorless to yellow; under a positive voltage, the yellow changed back to colorless, showing good electrochromic performance.

[0109] Example 3

[0110] The preparation process of the conjugated polymer in this example includes:

[0111] Synthesis of Intermediate 3-1: Intermediate 3-1 was synthesized according to the synthesis method of Intermediate 1-2 in Example 1, wherein 2-hexyldecanoic acid in Example 1 was replaced by 2-butyldodecanoic acid.

[0112] Synthesis of Intermediate 3-2: Intermediate 3-1 (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. The mixture was purged with argon for 30 minutes to remove oxygen, cooled to -78 °C, and then n-butyllithium (1.0 eq) was added. The mixture was stirred and heated to room temperature, and then the resulting solution was added to a solution of iron(III) acetylacetonate (30 mmol, 1.0 eq) in tetrahydrofuran (80 mL). The mixture was purged with argon and reacted at room temperature. Finally, the product was separated by column chromatography to obtain Intermediate 3-2 with a yield of 55%.

[0113] Synthesis of Intermediate 3-3: Intermediate 3-3 was synthesized according to the synthesis method of Intermediate 1-3 in Example 1, wherein Intermediate 1-2 in Example 1 was replaced by Intermediate 3-2.

[0114] Synthesis of Conjugated Polymer: The conjugated polymer was synthesized according to the synthesis method of the conjugated polymer in Example 2, with only the reaction substrate replaced by Intermediate 3-3.

[0115] In this example, the structural formula of the prepared conjugated polymer is shown in Formula (Ⅲ-1):

[0116]

[0117] In this example, n in Formula (Ⅲ-1) is 60, and the structural formula of the molecule of Formula (Ⅲ-1) is based on Formula Ⅲ, where R 1 is 2-butyldodecyl, R 2 is H, and Ar is a benzene ring.

[0118] The conjugated polymer in this example was used to prepare an electrochromic medium in the same method as in Example 1. In the electrochromic medium, the poor solvent is a mixture of tetrahydrofuran and xylene, and the volume ratio of tetrahydrofuran to xylene is 4:1. The concentration of the conjugated polymer is 30 mg / mL. The electrochromic medium was spin-coated on an ITO glass electrode to obtain an electrochromic film, and the electrochromic film was doped in an acetonitrile solution of copper(II) perchlorate. Then it was 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 colorless to orange; under a positive voltage, the orange color changes back to colorless, showing good electrochromic performance.

[0119] Example 4

[0120] The preparation process of the conjugated polymer in this example includes:

[0121] Synthesis of intermediate 4-1 and intermediate 4-2: Intermediate 4-1 and intermediate 4-2 were synthesized according to the synthesis method of intermediate 1-2 in Example 1, where 2-hexyldecanoic acid was replaced with 2-propylhexanoic acid.

[0122] Synthesis of the conjugated polymer: The conjugated polymer was synthesized according to the synthesis method of the conjugated polymer in Example 2, only replacing the reaction substrates with intermediate 4-1 and intermediate 4-2.

[0123] In this example, the structural formula of the prepared conjugated polymer is shown as formula (IV-1):

[0124]

[0125] In this example, x is 15, y is 20, and n is 12 in formula (IV-1). The structural formula in formula (IV-1) is based on formula IV, where R 1 and R 2 are 2-propylhexyl ester groups, Ar 1 is a benzene ring substituted with p-methoxy, and Ar 2 is a benzene ring.

[0126] The conjugated polymer in this example was used to prepare an electrochromic medium in the same method as in Example 1. In the electrochromic medium, the poor solvent is a mixture of tetrahydrofuran and γ-butyrolactone, and the volume ratio of tetrahydrofuran to γ-butyrolactone is 4:1. The concentration of the conjugated polymer is 3 mg / mL. 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 chloride. Then it was 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 colorless to yellow; under a positive voltage, the yellow changes back to colorless, showing good electrochromic performance.

[0127] Example 5

[0128] The preparation process of the conjugated polymer in this example includes:

[0129] Synthesis of intermediate 5-1: Intermediate 5-1 was synthesized according to the synthesis method of intermediate 2-2 in Example 2.

[0130] Synthesis of intermediate 5-2: Intermediate 5-2 was synthesized according to the synthesis method of intermediate 2-1 in Example 2, where 2-ethylhexanol was replaced with 2-octyldodecanol.

[0131] Synthesis of Intermediate 5-3: Lithium diisopropylamide (20.4 mmol, 3.0 eq.) was added to 50 mL of diethyl ether at 0 °C in an ice-water bath. Compound 5-2 (1.0 eq.) was slowly added, and then the mixture was stirred at room temperature. After that, the temperature was lowered to 0 °C again, and tributyltin chloride (20.4 mmol, 3.0 eq.) was added and stirred. Finally, the reaction solution was diluted with 100 mL of diethyl ether, washed with water, dried, and the intermediate 5-3 was obtained by column chromatography with a yield of 95%.

[0132] Synthesis of Conjugated Polymer: The obtained intermediate 5-3 (1.0 eq), intermediate 5-1 (0.75 eq), 4,7-dibromo-2,1,3-benzothiadiazole (0.25 eq), tris(dibenzylideneacetone)dipalladium (0.01 mmol, 0.02 eq) and tris(o-tolyl)phosphine (0.004 mmol, 0.08 eq) were added to 20 mL of toluene, and the mixture was freeze-pumped three times and reacted at 100 °C for 48 h. After the reaction was completed, the product was precipitated into 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 conjugated polymer with a yield of 76%.

[0133] In this example, the structural formula of the prepared conjugated polymer is shown in Formula (V-1):

[0134]

[0135] In this example, x is 18, y is 45, and n is 51 in Formula (V-1). The structural formula of the molecule of Formula V-1 is based on Formula V, where R 1 is 2-octyldodecyloxy, and R 2 is H.

[0136] The conjugated polymer in this example was used to prepare an electrochromic medium in the same way as in Example 1. In the electrochromic medium, the poor solvents are a mixture of ethyl acetate and xylene, and the volume ratio of ethyl acetate to xylene is 6:1. The concentration of the conjugated polymer is 5 mg / mL. 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 ferric chloride. Then it was 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 colorless to black; under a positive voltage, the black color changes back to colorless, showing good electrochromic performance.

[0137] Example 6

[0138] The preparation process of the conjugated polymer in this example includes:

[0139] Synthesis of Intermediate 6-1: Intermediate 6-1 was synthesized according to the synthesis method of Intermediate 1-2, wherein 2-hexyldecanoic acid was replaced with 2-butyl octanoic acid.

[0140] Synthesis of Intermediate 6-2: Intermediate 6-2 was synthesized according to the synthesis method of Intermediate 3-2, wherein the reaction substrate was replaced with Intermediate 6-1.

[0141] Synthesis of Conjugated 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. The flask was evacuated and purged with argon three times, and then purged with argon to remove oxygen. Intermediate 6-2 (1.0 eq) was separately added to a vial. After adding N-methylpyrrolidone (2 mL) to the vial, it was purged with argon to remove oxygen. The deoxygenated Intermediate 6-2 and N-methylpyrrolidone were added to the reaction flask using a syringe. The vial was washed twice with 2 mL of N-methylpyrrolidone, and the washing solution was 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. The solid was washed with methanol and dried under vacuum to obtain conjugated polymer powder with a yield of 60%.

[0142] In this example, the structural formula of the prepared conjugated polymer is shown in Formula (VI-1):

[0143]

[0144] In this example, n in Formula (VI-1) is 45, and the structural formula of the molecule of Formula VI-1 is based on Formula VI, wherein R in Formula VI 1 is 2-butyl octyl ester group, R 2 is methyl, and Ar is 2,1,3-benzothiadiazole.

[0145] The conjugated polymer in this example was prepared into an electrochromic medium by the same method as in Example 1. In the electrochromic medium, the poor solvent was a mixture of tetrahydrofuran and dichloromethane, and the volume ratio of tetrahydrofuran to dichloromethane was 1:1. The concentration of the conjugated polymer was 15 mg / mL. 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) perchlorate. 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 a positive voltage, the cyan state changed back to a colorless state, showing good electrochromic performance.

[0146] Example 7

[0147] The preparation process of the conjugated polymer in this example includes:

[0148] Synthesis of Intermediate 7-1: Intermediate 7-1 was synthesized according to the synthesis method of Intermediate 2-1, where 2-ethylhexanol was replaced by 2-propylheptanol.

[0149] Synthesis of Intermediate 7-2: Intermediate 7-2 was synthesized according to the synthesis method of Intermediate 2-2, where the reaction substrate was replaced by Intermediate 7-1.

[0150] Synthesis of the conjugated polymer: The conjugated polymer was synthesized according to the synthesis method of the conjugated polymer in Example 6, where the reaction substrate was replaced by Intermediate 7-1 and Intermediate 7-2.

[0151] In this example, the structural formula of the prepared conjugated polymer is shown in Formula (VII-1):

[0152]

[0153] In this example, x in Formula (VII-1) is 33, y is 17, n is 23, and the structural formula in Formula (VII-1) is based on Formula VII, where R 1 、R 2 is 2-propylheptyloxy, and Ar is 2,1,3-benzothiadiazole.

[0154] The conjugated polymer in this example was prepared into an electrochromic medium by the same method as in Example 1. In the electrochromic medium, the poor solvent was tetrahydrofuran, and the concentration of the conjugated polymer was 50 mg / mL. 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 p-toluenesulfonate. 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 a positive voltage, the black state changed back to a colorless state, showing good electrochromic performance.

[0155] Example 8

[0156] The preparation process of the conjugated polymer in this example included:

[0157] Synthesis of Intermediate 8-1: Intermediate 8-1 was synthesized according to the synthesis method of Intermediate 1-2 in Example 1, where 2-hexyldecanoic acid was replaced with 2-heptylundecanoic acid.

[0158] Intermediate 8-2 was

[0159] Intermediate 8-3 was

[0160] Synthesis of Intermediate 8-4: Intermediate 8-4 was synthesized according to the synthesis method of Intermediate 1-2 in Example 1, where 2-hexyldecanoic acid was replaced with 2-propylhexanoic acid.

[0161] Synthesis of Intermediate 8-5: Intermediate 8-5 was synthesized according to the synthesis method of the conjugated polymer in Example 6, where the reaction substrates were replaced with Intermediate 8-2, Intermediate 8-3, and Intermediate 8-4.

[0162] Synthesis of Intermediate 8-6: Intermediate 8-6 was synthesized according to the synthesis method of Intermediate 1-3 in Example 1, where the reaction substrate was replaced with Intermediate 8-5.

[0163] Synthesis of Intermediate 8-7: Intermediate 8-7 was synthesized according to the synthesis method of Intermediate 2-3 in Example 2, where the reaction substrates were replaced with Intermediate 8-1 and Intermediate 8-4.

[0164] Synthesis of the conjugated polymer: The conjugated polymer was synthesized according to the synthesis method of the conjugated polymer in Example 6, where the reaction substrates were replaced with Intermediate 8-6 and Intermediate 8-7.

[0165] In this example, the structural formula of the prepared conjugated polymer was as shown in Formula (VIII-1):

[0166]

[0167] In this embodiment, n in formula (VIII-1) is 27, and the structural formula of the molecule of formula (VIII-1) is based on formula VIII, that is, R in formula VIII 1 is 2-heptylundecanoate, R 2 is H, R 3 is methyl, R 4 is 2-propylhexanoate, and Ar is 2,1,3-benzothiadiazole.

[0168] The conjugated polymer in this embodiment is used to prepare an electrochromic medium by the same method as in Example 1. In the electrochromic medium, the poor solvent is a mixture of tetrahydrofuran and anisole with a volume ratio of 4:1, and the concentration of the conjugated polymer is 20 mg / mL. 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) bis(trifluoromethanesulfonyl)imide. 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 a green state; under a positive voltage, the green state changes back to a colorless state, showing good electrochromic performance.

[0169] 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 method for preparing an electrochromic film, characterized in that: include:: Dispersing a conjugated polymer in a poor solvent to obtain an electrochromic medium, and using a spin coating method or a blade coating method to prepare an electrochromic film from the electrochromic medium; placing the electrochromic film in a dopant solution for doping to obtain a final electrochromic film; The conjugated polymer is selected from Any of the following; Wherein, n is 1 to 200, x is 1 to 50, and y is 1 to 50; R1, R2, R3, and R4 are H, halogen, hydroxyl, amino, C1 to C 24 Alkyl groups between C1 and C 24 Alkyloxy, C1 to C 24 Substituted alkyloxy, C1 to C 24 The ester group between C1 and C 24 Substituted alkyl ester groups, C1 to C 24 The alkylamino and C6 to C 24 Any one of the aromatic groups; Ar, Ar1, Ar2 are C6 to C 12 An aromatic ring or a substituted aromatic ring between the two, wherein the aromatic ring is any one of benzene, naphthalene, anthracene, phenanthrene, fluorene, pyrene, perylene, fluoranthene, tetracene, pentacene, 2,1,3-benzothiadiazole, carbazole and benzimidazole; The solute in the dopant solution is a mixture of a redox pair of p-benzoquinone and hydroquinone, a mixture of a redox pair of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and hydroquinone, or any one of p-benzoquinone and its derivatives, tetrafluorotetracyanoquinodimethane and its derivatives, Cu(II) salts, Fe(III) salts, Fe(II) salts, Zn(II) salts, and Mn salts; the solvent in the dopant solution is any one of acetonitrile, water, and propylene carbonate.

2. The method for preparing the electrochromic film according to claim 1, characterized in that: The poor solvent is any one or more of tetrahydrofuran, n-hexane, chlorobenzene, xylene, γ-butyrolactone, dichloromethane, ethyl acetate, anisole, etc., and the concentration of the conjugated polymer in the poor solvent is 1 mg / mL to 50 mg / mL.

3. The method for preparing the electrochromic film according to claim 1, characterized in that: The ratio of the amount of the solute in the dopant solution to the amount of the conjugated polymer in the electrochromic medium is (1 to 1,000,000):

1.

4. The method for preparing the electrochromic film according to claim 1, characterized in that: When the electrochromic film is placed in a dopant solution for doping, the doping time is 30 seconds to 30 minutes.

5. The method for preparing the electrochromic film according to claim 1, characterized in that: When the electrochromic medium is made into an electrochromic film by spin coating, it includes: The electrochromic medium is dripped onto the substrate, and then the substrate is rotated to evenly spread the electrochromic medium, wherein the rotation speed of the substrate is 500 rpm to 5000 rpm, and the spin coating time is 5 s to 5 min.

6. The method for preparing the electrochromic film according to claim 1, characterized in that: When the electrochromic medium is made into an electrochromic film by a doctor blade coating method, it includes: The electrochromic medium is dripped onto the substrate, and then the electrochromic medium is scraped with a scraper or a wire rod until it is evenly spread, wherein the height of the scraped wet film is 5 μm to 500 μm, and the moving speed of the scraper or the wire rod is 10 mm / s to 60 mm / s.

7. The method for preparing the electrochromic film according to claim 1, characterized in that: The conjugated polymer is selected from Any one of; wherein x is 1 to 50, y is 1 to 50, and n is 1 to 200.

8. An electrochromic film, characterized in that: The electrochromic film is prepared by the preparation method described in any one of claims 1 to 7.

9. The electrochromic film according to claim 8, characterized in that ,, the thickness of the electrochromic film is 50nm to 50μm.

10. An electrochromic device, comprising 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 stacked in sequence, characterized in that: The electrochromic layer (2) comprises the electrochromic film according to claim 8 or 9.

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