An electrochromic thin film, its preparation method, and an electrochromic device

Abstract

This application provides an electrochromic thin film, its preparation method, and an electrochromic device, relating to the field of electrochromic technology. The raw material for this electrochromic thin film includes cesium-antimony co-doped tungsten oxide material. The preparation method includes: mixing a tungsten source, a cesium source, an antimony source, a reducing agent, and a first solvent to obtain a mixed solution; subjecting the mixed solution to a solvothermal reaction, followed by solid-liquid separation, to obtain solid cesium-antimony co-doped tungsten oxide; mixing the solid cesium-antimony co-doped tungsten oxide, a second solvent, and a binder to obtain a spin-coating solution; and coating the spin-coating solution onto conductive glass to obtain the electrochromic thin film. This application, by simultaneously doping cesium and antimony into tungsten oxide, produces a cesium-antimony co-doped tungsten oxide material with uniform elemental distribution, thereby enabling the prepared electrochromic thin film to possess advantages such as high visible light modulation rate, fast response speed, good cycle stability, high near-infrared shielding performance, and high thermal insulation performance.

Description

Technical Field

[0001] This application relates to the field of electrochromic technology, and in particular to an electrochromic thin film, its preparation method, and an electrochromic device. Background Technology

[0002] The solar radiation spectrum ranges from ultraviolet to near-infrared, including ultraviolet (UV, 200nm-400nm), visible (Vis, 400nm-780nm), and near-infrared (NIR, 780nm-2500nm). Although solar radiation at the ground is much less than that outside the atmosphere, it still has a significant impact on people's lives, especially in summer. The near-infrared band contains higher levels of heat, which can heat the interior spaces of buildings, cars, and ships. Studies show that south-facing windows receive approximately 1000 kWh / m² of solar energy annually. 2 This not only reduces the comfort of occupants but also consumes a significant amount of energy due to the use of air conditioning and other appliances. Smart windows are crucial physical barriers that reduce heat gain and loss in buildings; therefore, developing advanced glass technologies such as smart windows holds promise for reducing the energy required to maintain a comfortable indoor environment. Furthermore, developing an electrochromic glass with high shielding performance in the near-infrared band is of great significance and necessity for building a resource-saving society and promoting green development.

[0003] Currently, tungsten oxide is widely used in the preparation of electrochromic thin films due to its advantages such as high optical modulation rate, excellent cycling stability, and good memory effect. When free electrons are introduced into tungsten oxide by adding a third element or by increasing oxygen vacancies in the crystal lattice, metallic conductivity and strong NIR absorption can be induced. Based on this, transition metal-doped tungsten oxide materials are promising thermally insulating electrochromic materials. For example, cesium-doped tungsten oxide materials, due to their unique conductivity, superconductivity, photochromism, electrochromism, and optical properties, have been developed into various preparation methods for production applications. Among these methods, thermal reduction is difficult to control the material morphology, solid-state methods have high energy consumption and poor stability and reproducibility of the synthesized materials, electron beam evaporation methods use complex and expensive instruments, while solvothermal methods have the advantages of simplicity, controllable morphology, and low cost, and have become a commonly used technical solution.

[0004] However, due to the significant differences in ionic radii and atomic numbers between cesium and tungsten, their reaction rates in solvothermal processes differ considerably. This leads to uneven distribution of cesium and tungsten in cesium-doped tungsten oxide particles, preventing the achievement of optimal doping results. Therefore, there is an urgent need to find an electrochromic material with good doping performance and stronger absorption in the near-infrared range. Summary of the Invention

[0005] The purpose of this application is to provide an electrochromic thin film, its preparation method, and an electrochromic device. By preparing cesium antimony co-doped tungsten oxide material, the visible light modulation rate and response speed of the electrochromic thin film are improved, especially its high shielding performance and good heat insulation performance in the near-infrared band.

[0006] To achieve the above objectives, the technical solution of this application is as follows:

[0007] In a first aspect, this application provides an electrochromic thin film whose raw materials include cesium antimony co-doped tungsten oxide material.

[0008] Secondly, this application also provides a method for preparing the electrochromic thin film described in the first aspect, comprising:

[0009] A mixed solution is obtained by mixing a tungsten source, a cesium source, an antimony source, a reducing agent, and a first solvent.

[0010] The mixed solution was subjected to a solvothermal reaction, followed by solid-liquid separation, to obtain solid cesium antimony co-doped tungsten oxide.

[0011] The solid cesium antimony co-doped tungsten oxide, the second solvent, and the binder are mixed to obtain a spin-coating solution;

[0012] The spin coating solution is applied to conductive glass to obtain the electrochromic film.

[0013] In conjunction with the second aspect, in some preferred embodiments of this application, the preparation method satisfies at least one of the following conditions:

[0014] a. The tungsten source includes at least one of tungsten hexachloride and sodium tungstate;

[0015] b. The cesium source includes at least one of cesium hydroxide, cesium carbonate, and cesium sulfate;

[0016] c. The antimony source includes at least one of antimony hydroxide, antimony carbonate, and antimony trichloride;

[0017] d. The reducing agent includes at least one of acetic acid, oxalic acid, citric acid, and tartaric acid;

[0018] e. The first solvent includes at least one of anhydrous ethanol, ethylene glycol, isopropanol, and butanol;

[0019] f. The second solvent includes at least one of isoamyl acetate, isobutyl acetate, and isopropyl acetate;

[0020] g. The adhesive comprises at least one of acrylic resin, vinyl acetate resin, and chlorinated rubber;

[0021] h. The conductive glass includes ITO conductive glass or FTO conductive glass.

[0022] In some preferred embodiments of this application, the preparation method further satisfies at least one of the following conditions:

[0023] i. The ratio of the amount of the tungsten source, the cesium source, the antimony source, the reducing agent and the first solvent is 596 mg: (36-112) mg: (26-78) mg: (0-40) mL: (100-150) mL;

[0024] j. The molar ratio of the tungsten source, the cesium source, and the antimony source is 1:(0.2-0.5):(0.1-0.3);

[0025] k. The ratio of the solid cesium antimony co-doped tungsten oxide, the binder, and the second solvent is (300-500) mg: (4-5) mg: (2-5) mL.

[0026] In some preferred embodiments of this application, the preparation method further satisfies at least one of the following conditions:

[0027] l. The temperature of the solvothermal reaction is 160℃-220℃, and the time is 12h-36h;

[0028] m. The solid-liquid separation includes centrifugation or filtration;

[0029] n. After the solid-liquid separation, the method further includes: washing and drying the solid product obtained from the solid-liquid separation to obtain the solid cesium antimony co-doped tungsten oxide;

[0030] o. Before coating the conductive glass, the process further includes cleaning and surface-activating the conductive glass.

[0031] More preferably, the preparation method satisfies at least one of the following conditions:

[0032] p. The washing process includes: placing the solid product in a washing solution containing nitrocellulose and isoamyl acetate for ultrasonic dispersion and centrifugation;

[0033] q. The drying temperature is 60℃-80℃, and the time is 10h-15h;

[0034] r. The cleaning process includes: ultrasonic cleaning sequentially using detergent, deionized water, acetone, and ethanol;

[0035] s. The surface activation treatment includes: using a plasma instrument to activate the cleaned conductive glass.

[0036] More preferably, the preparation method satisfies at least one of the following conditions:

[0037] t. In the washing solution containing nitrocellulose and isoamyl acetate, the mass percentage of nitrocellulose is 0.5%-5%;

[0038] u. The plasma instrument has a working power of 150W-250W;

[0039] v. During the active treatment, the oxygen pressure changes in the following order: 120 Pa, 40 Pa, 90 Pa, 68 Pa.

[0040] w. The activation treatment time is 5 min-10 min.

[0041] In some preferred embodiments of this application, after coating the conductive glass, the process further includes: performing low-temperature annealing, wherein the temperature of the low-temperature annealing is 80℃-200℃ and the time is 1h-2h.

[0042] Thirdly, this application provides an electrochromic device, including the electrochromic thin film as described in the first aspect.

[0043] Preferably, the electrochromic device comprises a first transparent conductive layer, the electrochromic thin film, an ion-conducting layer, an ion-storage layer, and a second transparent conductive layer, which are stacked sequentially.

[0044] The beneficial effects of this application are:

[0045] In the electrochromic film of this application, cesium and antimony are doped into tungsten oxide to obtain a cesium-tungsten co-doped tungsten oxide material. On the one hand, antimony is used to coordinate the uneven elemental distribution caused by the inconsistent rates of cesium and tungsten in the solvothermal reaction; on the other hand, the co-doping of cesium and antimony can form more and more specialized electron-hole pairs, increasing the free carrier concentration and producing stronger absorption in the near-infrared range. Therefore, the electrochromic performance and infrared absorption rate of the cesium-tungsten co-doped tungsten oxide material are superior to those of cesium-doped tungsten oxide powder alone. Consequently, when the electrochromic film containing cesium-tungsten co-doped tungsten oxide material is applied in devices such as electrochromic glass, its near-infrared shielding and thermal insulation performance are better.

[0046] The preparation method of this application uses in-situ doping co-reduction method to prepare cesium antimony co-doped tungsten oxide material with uniform elemental distribution. This preparation method is simple, reproducible, and low in cost. The electrochromic film prepared has the advantages of high visible light modulation rate, fast response speed, good cycle stability, and high near-infrared shielding performance. Attached Figure Description

[0047] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0048] Figure 1 SEM image of the cesium-tungsten co-doped tungsten oxide material prepared in Example 1;

[0049] Figure 2 The transmittance diagrams for the cesium-tungsten co-doped tungsten oxide material prepared in Example 1 and the cesium-doped tungsten oxide material prepared in Comparative Example 1 are shown in the ultraviolet-visible-near-infrared range. Detailed Implementation

[0050] As used in this article:

[0051] "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such a composition, step, method, article, or apparatus. The conjunction "composed of" excludes any unnamed elements, steps, or components.

[0052] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0053] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0054] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2.689g. If we say that component A has "a" parts by mass and component B has "b" parts by mass, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it can mean that the mass of component A is aK and the mass of component B is bK (K is any number representing a multiplier). It is important to understand that, unlike the number of parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0055] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0056] The first objective of this application is to provide an electrochromic thin film, the raw material of which includes cesium antimony co-doped tungsten oxide material.

[0057] The inventors of this application have discovered that when cesium-doped tungsten oxide materials are prepared using a solvothermal method, the significant difference in the ionic radii and atomic coefficients of cesium and tungsten leads to an uneven distribution of these two elements within the cesium-doped tungsten oxide particles, thus affecting the electrochromic properties and infrared absorption rate of the cesium-doped tungsten oxide material. By introducing antimony, the uneven elemental distribution caused by inconsistent reaction rates can be reconciled, resulting in a cesium-antimony co-doped tungsten oxide material with a uniform elemental distribution. This material can then be used in electrochromic thin films of glass to improve near-infrared and thermal insulation properties.

[0058] Therefore, the second objective of this application is to provide a method for preparing the above-mentioned electrochromic thin film, comprising:

[0059] S1. Mix the tungsten source, cesium source, antimony source, reducing agent and first solvent to obtain a mixed solution;

[0060] S2. The mixed solution is subjected to a solvothermal reaction to separate the solid and liquid phases, yielding solid cesium antimony co-doped tungsten oxide;

[0061] S3. Mix the solid cesium antimony co-doped tungsten oxide, the second solvent, and the binder to obtain a spin-coating solution;

[0062] S4. The spin coating liquid is coated onto conductive glass to obtain the electrochromic film.

[0063] In some preferred embodiments of this application, the tungsten source in S1 includes at least one of tungsten hexachloride and sodium tungstate.

[0064] In some preferred embodiments of this application, the cesium source in S1 includes at least one of cesium hydroxide, cesium carbonate, and cesium sulfate.

[0065] In some preferred embodiments of this application, the antimony source in S1 includes at least one of antimony hydroxide, antimony carbonate, and antimony trichloride.

[0066] In some preferred embodiments of this application, the reducing agent in S1 includes at least one of acetic acid, oxalic acid, citric acid, and tartaric acid.

[0067] In some preferred embodiments of this application, the first solvent in S1 includes at least one of anhydrous ethanol, ethylene glycol, isopropanol, and butanol;

[0068] In some preferred embodiments of this application, the second solvent in S3 includes at least one of isoamyl acetate, isobutyl acetate, and isopropyl acetate.

[0069] In some preferred embodiments of this application, the adhesive in S3 includes at least one of acrylic resin, vinyl acetate resin, and chlorinated rubber.

[0070] In some preferred embodiments of this application, the conductive glass in S4 includes ITO conductive glass or FTO conductive glass, more preferably ITO conductive glass.

[0071] In some preferred embodiments of this application, the ratio of tungsten source, cesium source, antimony source, reducing agent and first solvent in S1 is 596mg:(36-112)mg:(26-78)mg:(0-40)mL:(100-150)mL, for example, it can be any value between 596mg:36mg:26mg:0mL:100mL, 596mg:50mg:50mg:15mL:120mL, 596mg:80mg:60mg:30mL:140mL, 596mg:110mg:78mg:40mL:150mL or 596mg:(36-112)mg:(26-78)mg:(0-40)mL:(100-150)mL.

[0072] In some preferred embodiments of this application, the molar ratio of the tungsten source, cesium source and antimony source in S1 is 1:(0.2-0.5):(0.1-0.3), for example, it can be any value between 1:0.2:0.1, 1:0.3:0.2, 1:0.4:0.3, 1:0.5:0.1, 1:0.25:0.25 or 1:(0.2-0.5):(0.1-0.3).

[0073] In some preferred embodiments of this application, the ratio of solid cesium antimony co-doped tungsten oxide, binder, and second solvent in S3 is (300-500) mg:(4-5) mg:(2-5) mL, for example, it can be any value between 300 mg:4 mg:2 mL, 350 mg:4.5 mg:3 mL, 400 mg:5 mg:4 mL, 450 mg:4.8 mg:5 mL, 500 mg:5 mg:5 mL, or (300-500) mg:(4-5) mg:(2-5) mL.

[0074] It should be noted that when preparing the spin coating solution in S3, the obtained solid cesium antimony co-doped tungsten oxide can be dissolved and dispersed in the second solvent first, and then the binder can be added and ultrasonically dispersed to ensure that the substances in the spin coating solution are evenly dispersed.

[0075] In some preferred embodiments of this application, the temperature of S2 during the solvothermal reaction is 160℃-220℃, for example, it can be 160℃, 180℃, 200℃, 220℃ or any value between 160℃ and 220℃; the time is 12h-36h, for example, it can be 12h, 15h, 18h, 20h, 24h, 30h, 32h, 36h or any value between 12h and 36h.

[0076] In some preferred embodiments of this application, the solid-liquid separation in S2 includes centrifugation or filtration, more preferably centrifugation.

[0077] In some preferred embodiments of this application, after solid-liquid separation in S2, the method further includes: washing and drying the solid product obtained by solid-liquid separation to obtain the solid cesium antimony co-doped tungsten oxide.

[0078] More preferably, the washing process includes: placing the solid product in a washing solution containing nitrocellulose and isoamyl acetate for ultrasonic dispersion and centrifugation.

[0079] Furthermore, in the washing solution containing nitrocellulose and isoamyl acetate, the nitrocellulose accounts for 0.5%-5% by mass.

[0080] After ultrasonic dispersion and centrifugation, the washing process should be repeated at least twice to ensure that impurities in the solid product are completely removed.

[0081] More preferably, the drying temperature is 60℃-80℃, for example, it can be 60℃, 65℃, 70℃, 75℃, 80℃, or any value between 60℃ and 80℃; the time is 10h-15h, for example, it can be 10h, 12h, 14h, 15h, or any value between 10h and 15h. More preferably, the washed solid product is placed in an oven and dried at 60℃ for 12h.

[0082] In some preferred embodiments of this application, before applying the spin coating liquid to the conductive glass in step S4, the conductive glass is further subjected to cleaning and surface activation treatment.

[0083] More preferably, the cleaning process includes ultrasonic cleaning sequentially using detergent, deionized water, acetone, and ethanol. This effectively removes both inorganic and organic impurities from the conductive glass, ensuring no interference between the electrolyte membrane layer and the conductive glass.

[0084] More preferably, the surface activation treatment includes: using a plasma instrument to activate the cleaned conductive glass.

[0085] The plasma analyzer operates at a power of 150W-250W, and the activation treatment lasts for 5-10 minutes. During the activation treatment, the oxygen pressure in the plasma analyzer changes sequentially to 120Pa, 40Pa, 90Pa, and 68Pa.

[0086] In some preferred embodiments of this application, the coating in S4 can be performed by spin coating to ensure that the spin coating liquid can be uniformly adhered to the conductive glass.

[0087] After coating is completed, the process also includes low-temperature annealing, which requires a temperature of 80℃-200℃ and a time of 1h-2h.

[0088] A third objective of this application is to provide an electrochromic device, including the electrochromic film as described in the first aspect. Specifically, the electrochromic device may be electrochromic smart dimming glass, an electrochromic display, or an automatic anti-glare rearview mirror for automobiles, etc.

[0089] In some preferred embodiments, the electrochromic device includes a first transparent conductive layer, the electrochromic thin film, an ion-conducting layer, an ion storage layer, and a second transparent conductive layer, which are sequentially stacked.

[0090] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0091] Example 1

[0092] This embodiment provides an electrochromic thin film, the raw material of which includes cesium antimony co-doped tungsten oxide material, and the specific preparation method includes:

[0093] (1) Add 596 mg of tungsten hexachloride, 112 mg of cesium hydroxide and 78 mg of antimony hydroxide to 100 mL of anhydrous ethanol, and add 40 mL of acetic acid and stir until homogeneous.

[0094] (2) Transfer the mixed solution obtained in step (1) to a solvothermal reactor and then place it in a drying oven for heating reaction. The temperature of the drying oven is 200℃ and the reaction time is 24h.

[0095] (3) Centrifuge the reaction liquid prepared in the reactor in step (2), then use nitrocellulose / isoamyl acetate solution to ultrasonically disperse and centrifuge the solid product, repeat the washing twice, and then place the solid product in an oven at 60°C to heat and dry for 12 hours.

[0096] (4) Dissolve 300 mg of the solid cesium antimony co-doped tungsten oxide material dried in step (3) in 3 mL of isoamyl acetate, add 4 g of acrylic resin, and disperse by ultrasonication to obtain a spin-coating solution containing cesium antimony co-doped tungsten oxide.

[0097] (5) The spin coating solution was uniformly attached to the tin-doped indium oxide (ITO) conductive glass by spin coating, and then annealed at 150°C for 1 hour to obtain a cesium-antimony co-doped tungsten oxide electrochromic film.

[0098] Example 2

[0099] The electrochromic film provided in this embodiment is the same as that in embodiment 1, except that the mass of tungsten hexachloride, cesium hydroxide and antimony hydroxide in step (1) is changed, specifically 596 mg of tungsten hexachloride, 89 mg of cesium hydroxide and 52 mg of antimony hydroxide.

[0100] Example 3

[0101] The electrochromic film provided in this embodiment is the same as that in embodiment 1, except that the mass of tungsten hexachloride, cesium hydroxide and antimony hydroxide in step (1) is changed, specifically 596 mg of tungsten hexachloride, 45 mg of cesium hydroxide and 26 mg of antimony hydroxide.

[0102] Example 4

[0103] The electrochromic film provided in this embodiment is the same as that in embodiment 1, except that the cesium hydroxide and antimony hydroxide in step (1) are replaced with cesium carbonate and antimony carbonate, with masses of 52 mg and 27 mg respectively.

[0104] Example 5

[0105] The electrochromic film provided in this embodiment is the same as that in embodiment 1, except that: the reducing agent in step (1) is replaced by oxalic acid, with a dosage of 20 mL, and the first solvent is replaced by ethylene glycol, with a dosage of 100 mL.

[0106] Example 6

[0107] The electrochromic film provided in this embodiment is the same as that in embodiment 1, except that: the reducing agent in step (1) is changed from acetic acid to citric acid, and the amount is 40 mL; the first solvent is changed from ethanol to butanol, and the amount is 100 mL; the solvothermal reaction temperature is 180 °C; and the reaction time is 24 h.

[0108] Example 7

[0109] The electrochromic film provided in this embodiment is the same as that in embodiment 1, except that the solvothermal reaction temperature in step (1) is changed to 220°C and the reaction time is 12h.

[0110] Example 8

[0111] The electrochromic film provided in this embodiment is the same as that in embodiment 1, except that the solvothermal reaction temperature in step (1) is changed to 160°C and the reaction time is 36h.

[0112] Comparative Example 1

[0113] This embodiment provides an electrochromic thin film, the raw material of which includes cesium-doped tungsten oxide material. The specific preparation method is the same as in embodiment 1, except that in step (1), tungsten hexachloride and cesium hydroxide are added to anhydrous ethanol and acetic acid is added and stirred evenly.

[0114] Electrochromic films prepared in Examples 1-8 and Comparative Example 1 were used to fabricate electrochromic glasses, comprising a first ITO conductive glass, an electrochromic film, an ion-conducting layer, an ion-storage layer, and a second ITO conductive glass stacked sequentially. The electrochromic properties of these electrochromic glasses were then tested, as shown in Table 1.

[0115] Table 1

[0116]

[0117] T in Table 1 c T represents the transmittance of the colored state at 630 nm. b The transmittance is the colorfast state, and ΔT is the transmittance of T. c and T b The difference between them represents the modulation rate in the visible light region, t c For the coloring response time, t b The fading response time represents the cyclic stability, while reversibility represents the cyclic stability.

[0118] Figure 1 The SEM image of the cesium antimony co-doped tungsten oxide material prepared in step (3) of Example 1 is given. It can be seen from the image that most of the cesium antimony co-doped tungsten oxide material is in the form of irregular particles or short rods.

[0119] Figure 2 The transmittance diagrams for the cesium-antimony co-doped tungsten oxide material prepared in Example 1 and the cesium-doped tungsten oxide material prepared in Comparative Example 1 are presented in the ultraviolet-visible-near-infrared range. Specifically, the cesium-antimony co-doped tungsten oxide material in Example 1 exhibits higher transmittance in the visible light region than the cesium-doped tungsten oxide material, indicating a higher visible light modulation rate. However, in the near-infrared region, the cesium-antimony co-doped tungsten oxide material shows lower transmittance, indicating high near-infrared shielding performance and good thermal insulation properties.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0121] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, any of the embodiments claimed above can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A method for preparing an electrochromic thin film, characterized in that, include: A tungsten source, a cesium source, an antimony source, a reducing agent, and a first solvent are mixed to obtain a mixed solution; wherein the tungsten source includes at least one of tungsten hexachloride and sodium tungstate, the cesium source includes at least one of cesium hydroxide, cesium carbonate, and cesium sulfate, the antimony source includes at least one of antimony hydroxide, antimony carbonate, and antimony trichloride, the reducing agent includes at least one of acetic acid, oxalic acid, citric acid, and tartaric acid, and the first solvent includes at least one of anhydrous ethanol, ethylene glycol, isopropanol, and butanol, and the ratio of the amount of the tungsten source, the cesium source, the antimony source, the reducing agent, and the first solvent is 596 mg: (36-112) mg: (26-78) mg: (0-40) mL: (100-150) mL; The mixed solution is subjected to a solvothermal reaction, followed by solid-liquid separation to obtain solid cesium antimony co-doped tungsten oxide; wherein the temperature of the solvothermal reaction is 160℃-220℃ and the time is 12h-36h. The solid cesium antimony co-doped tungsten oxide, the second solvent, and the binder are mixed to obtain a spin-coating solution; The spin coating solution is applied to conductive glass to obtain the electrochromic film.

2. The preparation method according to claim 1, characterized in that, At least one of the following conditions must be met: f. The second solvent includes at least one of isoamyl acetate, isobutyl acetate, and isopropyl acetate; g. The adhesive comprises at least one of acrylic resin, vinyl acetate resin, and chlorinated rubber; h. The conductive glass includes ITO conductive glass or FTO conductive glass.

3. The preparation method according to claim 1, characterized in that, It also meets at least one of the following conditions: j. The molar ratio of the tungsten source, the cesium source, and the antimony source is 1:(0.2-0.5):(0.1-0.3); k. The ratio of the solid cesium antimony co-doped tungsten oxide, the binder, and the second solvent is (300-500) mg: (4-5) mg: (2-5) mL.

4. The preparation method according to claim 1, characterized in that, It also meets at least one of the following conditions: m. The solid-liquid separation includes centrifugation or filtration; n. After the solid-liquid separation, the method further includes: washing and drying the solid product obtained from the solid-liquid separation to obtain the solid cesium antimony co-doped tungsten oxide; o. Before coating the conductive glass, the process further includes cleaning and surface-activating the conductive glass.

5. The preparation method according to claim 4, characterized in that, At least one of the following conditions must be met: p. The washing process includes: placing the solid product in a washing solution containing nitrocellulose and isoamyl acetate for ultrasonic dispersion and centrifugation; q. The drying temperature is 60℃-80℃, and the time is 10h-15h; r. The cleaning process includes: ultrasonic cleaning sequentially using detergent, deionized water, acetone, and ethanol; s. The surface activation treatment includes: using a plasma instrument to activate the cleaned conductive glass.

6. The preparation method according to claim 5, characterized in that, At least one of the following conditions must be met: t. In the washing solution containing nitrocellulose and isoamyl acetate, the mass percentage of nitrocellulose is 0.5%-5%; u. The plasma instrument has a working power of 150W-250W; v. During the active treatment, the oxygen pressure changes in the following order: 120 Pa, 40 Pa, 90 Pa, and 68 Pa. w. The activation treatment time is 5 min-10 min.

7. The preparation method according to any one of claims 1-6, characterized in that, After coating the conductive glass, the process further includes: performing low-temperature annealing, wherein the temperature of the low-temperature annealing is 80℃-200℃ and the time is 1h-2h.

8. An electrochromic device, characterized in that, This includes electrochromic films prepared by the preparation method according to any one of claims 1-7.

9. The electrochromic device as described in claim 8, characterized in that, The electrochromic device includes a first transparent conductive layer, the electrochromic thin film, an ion-conducting layer, an ion-storage layer, and a second transparent conductive layer, which are stacked sequentially.

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