Bi-doped WO3 electrochromic thin film, preparation method and glass

Abstract

This invention belongs to the field of electrochromic material preparation technology, specifically relating to a Bi-doped WO3 electrochromic thin film, its preparation method, and a glass substrate. The preparation method of the Bi-doped WO3 electrochromic thin film includes the following steps: dissolving H2WO4 in H2O2 solution to obtain a peroxytungstic acid solution; adding a Bi-containing substance to the peroxytungstic acid solution; dissolving the Bi-containing substance to obtain a Bi-peroxytungstic acid solution; spin-coating the Bi-peroxytungstic acid solution onto a conductive glass substrate; and calcining to obtain the Bi-doped WO3 electrochromic thin film; or evaporating and concentrating the Bi-peroxytungstic acid solution to obtain a Bi-peroxytungstic acid sol; spin-coating the Bi-peroxytungstic acid sol onto a conductive glass substrate; and calcining to obtain the Bi-doped WO3 electrochromic thin film. The Bi-doped WO3 electrochromic thin film prepared by this invention exhibits a transmittance change of 73% in 0.5M H2SO4 solution as the electrolyte and at a wavelength of 630 nm. The coloring and fading times are 3.6 s and 1.4 s, respectively, with a coloring efficiency of 52.52 cm⁻¹. 2 / C, remained stable after more than 1600 cycles of testing.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrochromic material preparation, and particularly relates to a Bi-doped WO3 electrochromic film, a preparation method and glass. BACKGROUND

[0002] Buildings consume 30-40% of the world's primary energy, and most of these energies are used for cooling, heating, lighting and electrical appliances, about 30% of which are lost through windows. Windows are crucial to the operation and comfort of buildings, and electrochromic glass can dynamically change color to adjust visible and near-infrared radiation according to the applied voltage, which is one of the solutions to reduce building energy loss. Compared with organic electrochromic materials, transition metal oxide materials are easy to process, have good reversibility and strong electrochemical stability, and are widely favored. Among them, tungsten trioxide (WO3) is a promising electrochromic material with a large light modulation range, high coloring efficiency and low price. In addition, compared with crystalline WO3, amorphous WO3 film has better electrochromic performance, faster switching response speed and higher color efficiency in the visible and near-infrared regions. However, due to the high disorder of the structure of amorphous WO3 and the weak adhesion between the substrate, the cycle stability is not ideal. SUMMARY

[0003] The first object of the present application is to provide a preparation method of a Bi-doped WO3 electrochromic film, which has simple operation steps and adopted equipment, and can be used to prepare the Bi-doped WO3 electrochromic film in an atmospheric environment.

[0004] The second object of the present application is to provide a Bi-doped WO3 electrochromic film, which has excellent electrochromic properties, a large light modulation range, fast response speed and good cycle stability.

[0005] The third object of the present application is to provide a glass containing the Bi-doped WO3 electrochromic film.

[0006] In order to achieve the above objects, the technical scheme adopted by the present application is as follows: a preparation method of a Bi-doped WO3 electrochromic film, comprising the following steps:

[0007] Step 1): dissolving H2WO4 in an H2O2 solution to obtain a tungsten peroxide acid solution, adding a Bi element-containing substance to the tungsten peroxide acid solution, and dissolving the Bi element-containing substance to obtain a Bi-tungsten peroxide acid solution;

[0008] Step 2): spin-coating the Bi-peroxotungstate solution obtained in step 1) on a conductive glass substrate, and baking to obtain a Bi-doped WO3 electrochromic film; or evaporating and concentrating the Bi-peroxotungstate solution in step 1) to obtain a Bi-peroxotungstate sol, spin-coating the Bi-peroxotungstate sol on a conductive glass substrate, and baking to obtain a Bi-doped WO3 electrochromic film.

[0009] Further, the Bi-doped WO3 electrochromic film has an amorphous structure.

[0010] Further, in the Bi-peroxotungstate solution in step 1), the ratio of Bi atoms to W atoms is 1:10-100.

[0011] Further, in step 1), the Bi-containing substance is one or more of metallic Bi powder, BiCl3, Bi(NO3)3, and Bi2O3; and the Bi-containing substance is dissolved by heating the peroxotungstate solution containing the Bi-containing substance to 30-100℃.

[0012] Further, in step 2), the Bi-peroxotungstate sol is prepared by evaporating and concentrating the Bi-peroxotungstate solution to 30-100% of the mass of the Bi-peroxotungstate solution under the condition of heating in a water bath at 50-100℃.

[0013] Further, in step 1), the mass percentage concentration of the H2O2 solution is 15-50%, and the molar concentration of the peroxotungstate solution is 0.1-1M.

[0014] Further, in step 2), the conductive glass substrate is a pretreated fluorine-doped tin oxide glass substrate, and the Bi-doped WO3 electrochromic film is prepared by spin-coating the Bi-peroxotungstate solution or the Bi-peroxotungstate sol on the pretreated fluorine-doped tin oxide glass substrate to form a film, and baking to obtain the Bi-doped WO3 electrochromic film.

[0015] Further, the baking temperature is 100-600℃, and the baking time is 0-6h.

[0016] A Bi-doped WO3 electrochromic film is prepared by the above method.

[0017] A glass containing the Bi-doped WO3 electrochromic film described above, and the glass is used in building doors and windows or glass curtain walls.

[0018] The beneficial effects of the present application are as follows:

[0019] The Bi-doped WO3 electrochromic film prepared in the embodiment 1 of the present application has a transmittance change of 73% under the condition of 630 nm wavelength, 0.5 M H2SO4 solution as electrolyte, and coloration and bleaching time of 3.6 s and 1.4 s, coloration efficiency of 52.52 cm 2 / C, and remains stable after more than 1600 cycles of test.

[0020] The preparation method of the Bi-doped WO3 electrochromic film of the present application is simple, the materials and preparation process cost are low, and the extreme environment conditions such as vacuum and precise and complex equipment are not needed, so that the large-scale production can be realized quickly. The low concentration of Bi element (Bi:W=1:30) can be used as a stabilizer of peroxotungstate solution. If more Bi element is added, for example, more than 0.06 g of Bi metal is added to 1.0 mL of peroxotungstate solution, the peroxotungstate solution will directly become a yellow gel-like substance, which cannot be completely dissolved even by stirring, which shows that the Bi element can promote the polymerization of peroxotungstate as a crosslinking agent or catalyst, and thus enhance the stability of Bi-peroxotungstate. Therefore, the Bi-peroxotungstate solution and Bi-peroxotungstate sol prepared by the present application are very stable and can be stored for years under indoor environmental conditions, which is beneficial to production application and commercialization.

[0021] The Bi-doped WO3 electrochromic film of the present application has high light transmittance and transparency in bleaching state, and presents deep blue color in coloration state, and has strong shielding ability to visible light and near-infrared light. The response speed in sulfuric acid solution is extremely fast, and good cycle stability is obtained under a suitable potential window. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is an atomic force microscope image of the Bi-doped WO3 electrochromic film in embodiment 1;

[0023] Figure 2 It is a schematic diagram of transmittance curve of the Bi-doped WO3 electrochromic film in embodiment 1 in original state, -0.3 V coloration state and 0.5 V bleaching state;

[0024] Figure 3 It is an in-situ response curve diagram of the Bi-doped WO3 electrochromic film in embodiment 1 under -0.3 / 0.5 V potential;

[0025] Figure 4 It is coloration efficiency of the Bi-doped WO3 electrochromic film in embodiment 1 under -0.3 V potential;

[0026] Figure 5 It is a long-term stability test curve diagram of the Bi-doped WO3 electrochromic film in embodiment 1 under -0.3 / 0.5 V potential.

[0027] Figure 6 Scanning electron microscope image of the Bi-doped WO3 electrochromic film in Example 2;

[0028] Figure 7 Schematic diagram of the transmittance curve of the Bi-doped WO3 electrochromic film in Example 2 in the original state, -0.3 V colored state and 0.5 V bleached state;

[0029] Figure 8 In-situ response curve diagram of the Bi-doped WO3 electrochromic film in Example 2 at -0.3 / 0.5 V potential.

[0030] Figure 9 Color efficiency of the Bi-doped WO3 electrochromic film in Example 2 at -0.3 V potential.

[0031] Figure 10 Long-term stability test curve diagram of the Bi-doped WO3 electrochromic film in Example 2 at -0.3 / 0.5 V potential.

[0032] Figure 11 Scanning electron microscope image of the Bi-doped WO3 electrochromic film in Example 3;

[0033] Figure 12 Schematic diagram of the transmittance curve of the Bi-doped WO3 electrochromic film in Example 3 in the original state, -0.5 V colored state and 0.5 V bleached state.

[0034] Figure 13 In-situ response curve diagram of the Bi-doped WO3 electrochromic film in Example 3 at -0.5 / 0.5 V potential. DETAILED DESCRIPTION

[0035] The application will be further described below with reference to the embodiments thereof and the accompanying drawings.

[0036] Example 1

[0037] The preparation method of the Bi-doped WO3 electrochromic film in the embodiment comprises the following steps:

[0038] (1) Pretreatment of fluorine-doped tin oxide (FTO) glass substrate

[0039] A piece of FTO glass substrate was ultrasonically cleaned with deionized water, anhydrous ethanol and deionized water for 15 min respectively to remove surface organic matter, and the surface liquid was blown off. The size of the FTO glass substrate was 3 cm x 2 cm.

[0040] (2) Preparation of Bi-peroxotungstic acid precursor sol

[0041] The Bi-doped WO3 electrochromic thin film of the present embodiment is prepared by the above method.

[0042] (3) Preparation of the Bi-doped WO3 electrochromic thin film

[0043] The Bi-doped WO3 electrochromic thin film is prepared by spin-coating the Bi-peroxotungstate sol obtained in step (2) on the pretreated FTO glass substrate at a rotation speed of 1500 rpm for 40 s, and then baking at 300°C for 2 h. The structure of the Bi-doped WO3 electrochromic thin film is amorphous.

[0044] The Bi-doped WO3 electrochromic thin film of the present embodiment is prepared by the above method.

[0045] The present embodiment provides a glass containing the Bi-doped WO3 electrochromic thin film prepared in the present embodiment, which can be used in building doors and windows or glass curtain walls.

[0046] The scanning electron microscope image of the Bi-doped WO3 electrochromic thin film prepared in the present embodiment is shown in Figure 1 .

[0047] The performance of the Bi-doped WO3 electrochromic thin film prepared in the present embodiment is shown in Figures 2-5 .

[0048] Example 2

[0049] The preparation method of the Bi-doped WO3 electrochromic thin film of the present embodiment comprises the following steps:

[0050] (1) Pretreatment of the fluorine-doped tin oxide (FTO) glass substrate

[0051] A piece of FTO glass substrate is ultrasonically cleaned with deionized water, anhydrous ethanol, and deionized water for 15 min respectively to remove surface organic matter, and the surface liquid is blown off. The size of the FTO glass substrate is 3 cm x 2 cm.

[0052] (2) Preparation of the Bi-peroxotungstate precursor solution

[0053] A 15 g H2WO4 was dissolved in 100 mL of 30% mass percentage H2O2, and stirred at 300 rpm for 4 days at room temperature. After standing for 6 h, a clear and transparent tungsten peroxide solution was obtained, and the concentration of the tungsten peroxide solution was 0.3 M. Bi2O3 was added to the tungsten peroxide solution, so that the ratio of Bi atoms to W atoms in the tungsten peroxide solution was 1:30. After the Bi2O3 was completely dissolved by heating the Bi2O3-added tungsten peroxide solution in a water bath at 80 °C for 8 h, a Bi-tungsten peroxide solution was obtained.

[0054] (3) Preparation of the Bi-doped WO3 electrochromic film

[0055] The Bi-tungsten peroxide solution obtained in step (2) was spin-coated on a pretreated FTO glass substrate at a speed of 1500 rpm for 40 s, and then calcined at 300 °C for 2 h to obtain a Bi-doped WO3 electrochromic film. The structure of the Bi-doped WO3 electrochromic film was amorphous.

[0056] The Bi-doped WO3 electrochromic film of the present embodiment was prepared by the above method.

[0057] The present embodiment provides a glass containing the Bi-doped WO3 electrochromic film prepared in the present embodiment, which can be used in building doors and windows or glass curtain walls.

[0058] The scanning electron microscope image of the Bi-doped WO3 electrochromic film prepared in the present embodiment is shown in Figure 6 .

[0059] The performance of the Bi-doped WO3 electrochromic film prepared in the present embodiment is shown in Figures 7-10 .

[0060] Example 3

[0061] The preparation method of the Bi-doped WO3 electrochromic film of the present embodiment comprises the following steps:

[0062] (1) Pretreatment of the fluorine-doped tin oxide (FTO) glass substrate

[0063] An FTO glass substrate was ultrasonically cleaned with deionized water, anhydrous ethanol, and deionized water for 15 min each to remove surface organic matter, and the surface liquid was blown off. The size of the FTO glass substrate was 3 cm x 2 cm.

[0064] (2) Preparation of the Bi-tungsten peroxide precursor solution

[0065] The Bi-doped WO3 electrochromic thin film of the present embodiment is prepared by the following method.

[0066] (3) Preparation of the Bi-doped WO3 electrochromic thin film

[0067] The Bi-doped WO3 electrochromic thin film of the present embodiment is prepared by the following method.

[0068] The Bi-doped WO3 electrochromic thin film of the present embodiment is prepared by the following method.

[0069] The Bi-doped WO3 electrochromic thin film of the present embodiment is prepared by the following method.

[0070] The Bi-doped WO3 electrochromic thin film of the present embodiment is prepared by the following method. Figure 11 The Bi-doped WO3 electrochromic thin film of the present embodiment is prepared by the following method. The Bi-doped WO3 electrochromic thin film of the present embodiment is prepared by the following method.

[0071] The Bi-doped WO3 electrochromic thin film of the present embodiment is prepared by the following method. Figures 12-13 The Bi-doped WO3 electrochromic thin film of the present embodiment is prepared by the following method. The Bi-doped WO3 electrochromic thin film of the present embodiment is prepared by the following method.

[0072] The Bi-doped WO3 electrochromic thin film of the present embodiment is prepared by the following method. The Bi-doped WO3 electrochromic thin film of the present embodiment is prepared by the following method.

[0073] The Bi-doped WO3 electrochromic thin film of the present embodiment is prepared by the following method. The Bi-doped WO3 electrochromic thin film of the present embodiment is prepared by the following method.

[0074] (1) Pretreatment of the fluorine-doped tin oxide (FTO) glass substrate The Bi-doped WO3 electrochromic thin film of the present embodiment is prepared by the following method.

[0075] The Bi-doped WO3 electrochromic thin film of the present embodiment is prepared by the following method. The Bi-doped WO3 electrochromic thin film of the present embodiment is prepared by the following method.

[0076] The Bi-doped WO3 electrochromic thin film of the present embodiment is prepared by the following method. The Bi-doped WO3 electrochromic thin film of the present embodiment is prepared by the following method.

[0077] A solution of 15 g of H2WO4 in 100 mL of 30% H2O2 by mass concentration was stirred at room temperature at a rotation speed of 300 rpm for 4 days, and a clear and transparent tungsten peroxide solution was obtained after standing for 6 h. The concentration of the tungsten peroxide solution was 0.3 M. Bi powder was added to the tungsten peroxide solution to make the ratio of Bi atoms to W atoms in the tungsten peroxide solution 1:30. After the Bi powder was completely dissolved by sealing the tungsten peroxide solution with the Bi powder and heating in a water bath at 80°C for 8 h, a Bi-tungsten peroxide solution was obtained.

[0078] (3) Preparation of a Bi-doped WO3 electrochromic film

[0079] The Bi-tungsten peroxide solution obtained in step (2) was spin-coated on a pretreated FTO glass substrate at a rotation speed of 1500 rpm for 40 s to form a film, and then the film was calcined at 300°C for 2 h to obtain a Bi-doped WO3 electrochromic film. The structure of the Bi-doped WO3 electrochromic film was amorphous.

[0080] The Bi-doped WO3 electrochromic film of the present embodiment was prepared by the above method.

[0081] The present embodiment provides a glass containing the Bi-doped WO3 electrochromic film prepared in the present embodiment, which can be used in building doors and windows or glass curtain walls.

[0082] Example 5

[0083] The preparation method of the Bi-doped WO3 electrochromic film of the present embodiment includes the following steps:

[0084] (1) Pretreatment of a fluorine-doped tin oxide (FTO) glass substrate

[0085] An FTO glass substrate was ultrasonically cleaned with deionized water, anhydrous ethanol, and deionized water for 15 min each to remove surface organic matter, and the surface liquid was blown off. The size of the FTO glass substrate was 3 cm x 2 cm.

[0086] (2) Preparation of a Bi-tungsten peroxide precursor solution

[0087] A solution of 15 g of H2WO4 in 100 mL of 30% H2O2 by mass concentration was stirred at room temperature at a rotation speed of 300 rpm for 4 days, and a clear and transparent tungsten peroxide solution was obtained after standing for 6 h. The concentration of the tungsten peroxide solution was 0.3 M. BiCl3 was added to the tungsten peroxide solution to make the ratio of Bi atoms to W atoms in the tungsten peroxide solution 1:30. After the BiCl3 was completely dissolved by sealing the tungsten peroxide solution with the Bi powder and heating in a water bath at 80°C for 8 h, a Bi-tungsten peroxide solution was obtained.

[0088] (3) Preparation of Bi-doped WO3 electrochromic thin film

[0089] The Bi-peroxotungstate solution obtained in step (2) was spin-coated on the pretreated FTO glass substrate at a rotation speed of 1500 rpm for 40 s to form a film, and then calcined at 300°C for 2 h to obtain a Bi-doped WO3 electrochromic thin film. The structure of the Bi-doped WO3 electrochromic thin film was amorphous structure.

[0090] The Bi-doped WO3 electrochromic thin film of the present embodiment was prepared by the above method.

[0091] The present embodiment provides a glass containing the Bi-doped WO3 electrochromic thin film prepared in the present embodiment, which can be applied in building doors and windows or glass curtain walls.

[0092] Example 6

[0093] The preparation method of the Bi-doped WO3 electrochromic thin film of the present embodiment comprises the following steps:

[0094] (1) Pretreatment of fluorine-doped tin oxide (FTO) glass substrate

[0095] A piece of FTO glass substrate was ultrasonically cleaned with deionized water, anhydrous ethanol, and deionized water for 15 min respectively to remove surface organic matter, and the surface liquid was blown off. The size of the FTO glass substrate was 3 cm x 2 cm.

[0096] (2) Preparation of Bi-peroxotungstate precursor solution

[0097] 15 g of H2WO4 was dissolved in 100 mL of 30% mass percentage H2O2, and stirred at a rotation speed of 300 rpm at room temperature for 4 days. After standing for 6 h, a clear and transparent peroxotungstate solution was obtained, and the concentration of the peroxotungstate solution was 0.3 M. Bi(NO3)3 was added to the peroxotungstate solution to make the ratio of Bi atoms to W atoms in the peroxotungstate solution 1:30. Then the peroxotungstate solution with Bi powder was sealed and heated in a water bath at 80°C for 8 h until Bi(NO3)3 was completely dissolved, to obtain a Bi-peroxotungstate solution.

[0098] (3) Preparation of Bi-doped WO3 electrochromic thin film

[0099] The Bi-peroxotungstate solution obtained in step (2) was spin-coated on the pretreated FTO glass substrate at a rotation speed of 1500 rpm for 40 s to form a film, and then calcined at 300°C for 2 h to obtain a Bi-doped WO3 electrochromic thin film. The structure of the Bi-doped WO3 electrochromic thin film was amorphous structure.

[0100] The Bi-doped WO3 electrochromic film of the embodiment is prepared by the above method.

[0101] The embodiment provides a glass containing the Bi-doped WO3 electrochromic film prepared in the embodiment, which can be applied to building doors and windows or glass curtain walls.

[0102] Experimental Example 1

[0103] The Bi-doped WO3 electrochromic film prepared in Example 1 is used as a working electrode, a platinum sheet is used as a counter electrode, saturated Ag / AgCl is used as a reference electrode, 0.5M H2SO4 solution is used as an electrolyte, an electrochemical workstation of a three-electrode system and an ultraviolet-visible-near infrared spectrophotometer are used to test the electrochromic performance, and the test structure is as shown in Figures 2-5 It can be seen that the Bi-doped WO3 electrochromic film prepared in Example 1 has a coloration time of 3.6s and a bleaching time of 1.4s, a coloration efficiency of 52.52cm 2 / C, and a transmittance change of 73% between the coloration state at -0.3V and the bleaching state at -0.5V. Figure 2 Figure 3 It can be seen that the Bi-doped WO3 electrochromic film prepared in Example 1 is stable after more than 1600 cycles of test. Figure 4 Figure 5 Experimental Example 2

[0104] The Bi-doped WO3 electrochromic film prepared in Example 2 is used as a working electrode, a platinum sheet is used as a counter electrode, saturated Ag / AgCl is used as a reference electrode, 0.5M H2SO4 solution is used as an electrolyte, an electrochemical workstation of a three-electrode system and an ultraviolet-visible-near infrared spectrophotometer are used to test the electrochromic performance, and the test structure is as shown in It can be seen that the Bi-doped WO3 electrochromic film prepared in Example 2 has a transmittance change of about 60% between the coloration state at -0.3V and the bleaching state at -0.5V.

[0105] Figures 7-10 It can be seen that the Bi-doped WO3 electrochromic film prepared in Example 2 has a coloration time of 3.6s and a bleaching time of 1.4s, a coloration efficiency of 52.52cm 2 / C, and a transmittance change of 73% between the coloration state at -0.3V and the bleaching state at -0.5V. Figure 7 Figure 8 It can be seen that the Bi-doped WO3 electrochromic film prepared in Example 2 is stable after more than 1600 cycles of test. Figure 9 ​As can be seen, the Bi-doped WO3 electrochromic film prepared in Example 2 has a very short fading and coloring time, with coloring and fading times of 2.4 s and 0.8 s, respectively, and a coloring efficiency of 50.6 cm⁻¹. 2 / C, from Figure 8 and Figure 9 It can be seen that the Bi-doped WO3 electrochromic film prepared in Example 2 has a faster response speed. From Figure 10 It can be seen that the Bi-doped WO3 electrochromic film prepared in Example 2 remained stable after more than 1200 cycles of testing.

[0106] Experimental Example 3

[0107] The Bi-doped WO3 electrochromic film prepared in Example 3 was used as the working electrode, a platinum sheet as the counter electrode, and saturated Ag / AgCl as the reference electrode. 0.5 M H₂SO₄ solution was used as the electrolyte. Electrochromic performance was tested using a three-electrode electrochemical workstation and a UV-Vis-NIR spectrophotometer. The test structure is shown below. Figures 12-13 As shown. From Figure 12 It can be seen that, with 0.5M H2SO4 solution as the electrolyte and a wavelength of 630 nm, the Bi-doped WO3 electrochromic film prepared in Example 3 exhibits a transmittance change of approximately 40% between the colored state and the bleached state at -0.5V. Figure 13 It can be seen that the Bi-doped WO3 electrochromic film prepared in Example 3 has a very short fading and coloring time, with coloring and fading times of 2.1 s and 1 s, respectively. Figure 13 It can be seen that the Bi-doped WO3 electrochromic film prepared in Example 3 has a faster response speed.

[0108] As can be seen from Experiments 1, 2 and 3, the Bi-doped WO3 electrochromic film prepared by directly spin-coating the Bi-peroxytungstic acid solution onto a conductive glass substrate and then calcining it has a faster response speed. The Bi-doped WO3 electrochromic film prepared by concentrating the Bi-peroxytungstic acid solution into a Bi-peroxytungstic acid sol and then calcining the Bi-peroxytungstic acid sol has a larger light modulation range and better stability.

[0109] The Bi-doped WO3 electrochromic thin film prepared by this invention has two major advantages: (1) the spatial arrangement of the [WO6] octahedral lattice in amorphous WO3 is irregular, providing abundant open polygonal ion transfer channels; (2) Bi doping leads to a globally disordered but locally ordered structure of the ion channels and a larger interplanar spacing. These advantages enable the Bi-doped WO3 electrochromic thin film to possess accelerated charge transport dynamics, promoting H +The insertion / extraction process of ions in the lattice, in turn, makes the thin film exhibit excellent response speed. Compared with the original solution, the concentrated solution has higher viscosity, the thickness of the film prepared under the same spin coating conditions increases, and the adhesion to the substrate is also enhanced. Therefore, the film prepared by spin coating and calcination of Bi-peroxotungstate concentrated solution has higher thickness and more active units, can embed more ions in the electrochromic process, and exhibits larger optical modulation range and higher stability.

Claims

1. A method for preparing a Bi-doped WO3 electrochromic thin film, characterized in that, The method comprises the following steps: Step 1): dissolving H2WO4 in H2O2 solution to obtain a tungsten peroxide acid solution, adding a Bi-containing substance into the tungsten peroxide acid solution, and dissolving the Bi-containing substance to obtain a Bi-tungsten peroxide acid solution; Step 2): spin-coating the Bi-tungsten peroxide acid solution obtained in step 1) on a conductive glass substrate, and baking to obtain a Bi-doped WO3 electrochromic film; or evaporating and concentrating the Bi-tungsten peroxide acid solution in step 1) to obtain a Bi-tungsten peroxide acid sol, spin-coating the Bi-tungsten peroxide acid sol on a conductive glass substrate, and baking to obtain a Bi-doped WO3 electrochromic film; In the Bi-tungsten peroxide acid solution in step 1), the ratio of Bi atoms to W atoms is 1:10-100.

2. The method for preparing Bi-doped WO3 electrochromic thin films according to claim 1, characterized in that, The Bi-doped WO3 electrochromic film has an amorphous structure.

3. The method for preparing Bi-doped WO3 electrochromic thin films according to claim 1, characterized in that, In step 1), the Bi-containing substance is one or more of metallic Bi powder, BiCl3, Bi(NO3)3 and Bi2O3; and the Bi-containing substance is dissolved by heating the tungsten peroxide acid solution containing the Bi-containing substance to 30-100 ℃.

4. The method for preparing Bi-doped WO3 electrochromic thin films according to claim 1, characterized in that, In step 2), the Bi-tungsten peroxide acid sol is prepared by evaporating and concentrating the Bi-tungsten peroxide acid solution to 30-100% of the mass of the Bi-tungsten peroxide acid solution at 50-100 ℃.

5. The method for preparing Bi-doped WO3 electrochromic thin films according to claim 1, characterized in that, In step 1), the mass percentage concentration of the H2O2 solution is 15-50%, and the molar concentration of the tungsten peroxide acid solution is 0.1-1 M.

6. The method for preparing Bi-doped WO3 electrochromic thin films according to claim 1, characterized in that, In step 2), the conductive glass substrate is a fluorine-doped tin oxide glass substrate, and the Bi-doped WO3 electrochromic film is prepared by spin-coating the Bi-tungsten peroxide acid solution or the Bi-tungsten peroxide acid sol on the fluorine-doped tin oxide glass substrate to form a film, and baking to obtain the Bi-doped WO3 electrochromic film.

7. The method for preparing Bi-doped WO3 electrochromic thin films according to claim 6, characterized in that, The baking temperature is 100-600 ℃, and the baking time is 0-6 h.

8. A Bi-doped WO3 electrochromic thin film, characterized by, The method is prepared according to claim 1.

9. A glass characterized by, The glass contains the Bi-doped WO3 electrochromic film according to claim 8, and the glass is applied to building doors and windows or glass curtain walls.

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