Bi-go double-doped wO3 electrochromic thin film, preparation method and application thereof

Abstract

This invention relates to a Bi-GO dual-doped WO3 electrochromic thin film, its preparation method, and its application. The preparation method of the Bi-GO dual-doped WO3 electrochromic thin film includes the following steps: dissolving tungstic acid in hydrogen peroxide solution to obtain a peroxytungstic acid solution; adding a bismuth-containing substance to the peroxytungstic acid solution, and dissolving the bismuth-containing substance to obtain a Bi-peroxytungstic acid solution; adding a graphene-based nanosheet dispersion to the Bi-peroxytungstic acid solution, stirring and heating to form a uniform Bi-GO-peroxytungstic acid sol; spin-coating the Bi-GO-peroxytungstic acid sol onto a conductive glass substrate, and calcining to obtain the final product. The Bi-GO dual-doped WO3 electrochromic thin film prepared by this invention exhibits a transmittance change of 85% in 0.5M H2SO4 solution as the electrolyte and at a wavelength of 630 nm, with coloring and fading times of 1.8 s and 1.8 s respectively, and a coloring efficiency of 65.9 cm⁻¹. 2 / C, remained stable after more than 10,000 cycles of testing.

Description

Technical Field

[0001] This invention belongs to the field of electrochromic material preparation technology, specifically relating to a Bi-GO dual-doped WO3 electrochromic thin film, its preparation method, and its application. Background Technology

[0002] Buildings consume 30-40% of the world's primary energy, mostly for cooling, heating, lighting, and appliances, with approximately 30% of this energy lost through windows. Windows are crucial for building operation and comfort, and electrochromic glass, which dynamically changes color based on applied voltage to modulate visible and near-infrared radiation, is one solution to reduce building energy loss. Compared to organic electrochromic materials, transition metal oxides are easier to process, exhibit good reversibility, and strong electrochemical stability, making them widely favored. Among them, tungsten trioxide (WO3) is a promising electrochromic material with advantages such as a wide light modulation range, high coloring efficiency, and low cost. Furthermore, compared to crystalline WO3, amorphous WO3 films exhibit better electrochromic performance, with faster switching response speeds and higher color rendering efficiency in the visible and near-infrared regions. However, the high disorder of the amorphous WO3 structure and its weak adhesion to the substrate result in less than ideal cycling stability.

[0003] Patent application CN116789368A discloses a Bi-doped WO3 electrochromic thin film, its preparation method, and a glass. This Bi-doped WO3 electrochromic thin film, using 0.5M H2SO4 solution as the electrolyte and at a wavelength of 630 nm, exhibits a transmittance change of up to 73%, with coloring and fading times of 3.6 s and 1.4 s, respectively, and a coloring efficiency of 52.52 cm⁻¹. 2 / C, remained stable after more than 1600 cycles of testing, indicating poor coloring efficiency and cycling stability of the Bi-doped WO3 electrochromic film. Summary of the Invention

[0004] The purpose of this invention is to provide a Bi-GO dual-doped WO3 electrochromic thin film with a coloring efficiency of 65.9 cm⁻¹. 2 / C, remained stable after more than 10,000 cycles of testing.

[0005] The second objective of this invention is to provide a method for preparing Bi-GO dual-doped WO3 electrochromic thin films.

[0006] The third objective of this invention is to provide an application of a Bi-GO dual-doped WO3 electrochromic thin film.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing a Bi-GO dual-doped WO3 electrochromic thin film includes the following steps:

[0009] Step 1): Dissolve tungstic acid in hydrogen peroxide solution to obtain peroxytungstic acid solution. Add a bismuth-containing substance to the peroxytungstic acid solution. After the bismuth-containing substance dissolves, a Bi-peroxytungstic acid solution is obtained.

[0010] Step 2): Add graphene-based nanosheet dispersion to the Bi-peroxytungstic acid solution obtained in Step 1), stir and heat to form a uniform Bi-GO-peroxytungstic acid sol.

[0011] Step 3): Spin coat the Bi-GO-peroxytungstic acid sol obtained in step 2) onto a conductive glass substrate, and then calcine it to obtain the final product.

[0012] Furthermore, the graphene-based material mentioned in step 2) is graphene oxide or graphene oxide-reduction.

[0013] Furthermore, the preparation method of Bi-GO-peroxytungstic acid sol in step 2) is as follows: after adding the graphene-based material nanosheet dispersion to the Bi-peroxytungstic acid solution, stir and heat at 50-100℃ for 4-12 hours to obtain the solution.

[0014] Furthermore, the mass ratio of graphene-based material to tungstic acid is 0.0001 to 0.03:1, and the concentration of the graphene-based material nanosheet dispersion is 0.5 to 8 mg / mL.

[0015] Furthermore, the preparation method of the Bi-peroxytungstic acid solution is as follows: after adding the bismuth-containing substance to the peroxytungstic acid solution, sealing it, and heating it at 60-100℃ for 4-12 hours, the solution is obtained; the bismuth-containing substance is one or more of bismuth trioxide, bismuth powder, or bismuth nitrate; the ratio of tungsten atoms to bismuth atoms in the Bi-peroxytungstic acid solution is 1:30; each g of the tungstic acid corresponds to 5-10 mL of hydrogen peroxide solution; and the volume ratio of the Bi-peroxytungstic acid solution to the graphene-based nanosheet dispersion is 10-2:1.

[0016] Furthermore, the mass percentage concentration of the hydrogen peroxide solution in step 1) is 15-50%, and the molar concentration of the peroxytungstic acid solution is 0.1-1M.

[0017] Furthermore, the conductive glass substrate in step 3) is a fluorine-doped tin oxide glass substrate, and the baking temperature is 100-600℃, and the baking time is 0-6h.

[0018] A Bi-GO double-doped WO3 electrochromic thin film was prepared using the above-described method for preparing Bi-GO double-doped WO3 electrochromic thin films.

[0019] Furthermore, the structure of the Bi-GO dual-doped WO3 electrochromic film is an amorphous structure.

[0020] A type of glass containing the aforementioned Bi-GO dual-doped WO3 electrochromic film, and the application of the glass in building doors and windows or glass curtain walls.

[0021] The beneficial effects of this invention are:

[0022] The Bi-GO dual-doped WO3 electrochromic film prepared in Example 1 of this invention exhibits a transmittance change of 85% in 0.5M H2SO4 solution as the electrolyte and at a wavelength of 630 nm. The coloring and fading times are 1.8 s and 1.8 s, respectively, with a coloring efficiency of 65.9 cm⁻¹. 2 / C, remained stable after more than 10,000 cycles of testing.

[0023] The preparation method of the Bi-GO dual-doped WO3 electrochromic film of this invention is simple, uses low-cost materials and preparation processes, does not require extreme environmental conditions such as vacuum or sophisticated equipment, and can be rapidly scaled up. Low concentrations of Bi (Bi:W = 1:30) can act as a stabilizer for peroxytungstic acid solution. If more Bi is added, for example, more than 0.06 g of Bi metal is added to 1.0 mL of peroxytungstic acid solution, the solution directly turns into a yellow gel-like substance that cannot be completely dissolved even with stirring. This indicates that Bi can act as a crosslinking agent or catalyst to promote the polymerization of peroxytungstic acid, thereby enhancing the stability of Bi-peroxytungstic acid. Therefore, the Bi-peroxytungstic acid solution and Bi-GO-peroxytungstic acid sol prepared by this invention are very stable and can be stably stored for several years under indoor environmental conditions, which is beneficial for production applications and commercialization. Electron transport in graphene possesses the properties of two-dimensional Dirac fermions, and charge carriers can move at almost the speed of light. Graphene-based materials contain a large number of functional groups, unlike graphene which has empty p-type functional groups. z While the presence of functional groups can increase the speed of ion and electron movement, it can also improve the charge transfer efficiency in the WO3 lattice. Furthermore, the abundance of functional groups facilitates the formation of a uniform sol in graphene-based materials and their chemical bonding with WO3 during calcination.

[0024] The Bi-GO dual-doped WO3 electrochromic film of this invention exhibits high transmittance and transparency in the faded state, and displays a deep blue color in the colored state, possessing strong shielding capabilities against visible and near-infrared light. It also exhibits extremely fast response in sulfuric acid solution and good cycling stability within a suitable potential window. Attached Figure Description

[0025] Figure 1 This is a scanning electron microscope image of the Bi-GO dual-doped WO3 electrochromic film in Example 1;

[0026] Figure 2 This is a schematic diagram of the transmittance curves of the Bi-GO double-doped WO3 electrochromic film in Example 1 in the original state, the -0.3V colored state, and the 0.5V fading state.

[0027] Figure 3 The in-situ response curves of the Bi-GO double-doped WO3 electrochromic film in Example 1 at potentials of -0.3 / 0.5V are shown.

[0028] Figure 4 The color development efficiency of the Bi-GO double-doped WO3 electrochromic film in Example 1 at a potential of -0.3V and a wavelength of 630nm is given.

[0029] Figure 5 The graph shows the long-term stability test curves of the Bi-GO double-doped WO3 electrochromic film in Example 1 at potentials of -0.3 / 0.5V.

[0030] Figure 6 This is a schematic diagram of the transmittance curves of the Bi-GO double-doped WO3 electrochromic film in Example 2 in the original state, the -0.3V colored state, and the 0.5V fading state.

[0031] Figure 7 The in-situ response curves of the Bi-GO double-doped WO3 electrochromic film in Example 2 at potentials of -0.3 / 0.5V are shown.

[0032] Figure 8 The color development efficiency of the Bi-GO double-doped WO3 electrochromic film in Example 2 at a potential of -0.3V and a wavelength of 630nm is given.

[0033] Figure 9 This is a schematic diagram of the transmittance curves of the Bi-GO double-doped WO3 electrochromic film in Example 3 in the original state, -0.5V colored state, and 0.5V faded state.

[0034] Figure 10 The in-situ response curves of the Bi-GO double-doped WO3 electrochromic film in Example 3 at potentials of -0.3 / 0.5V are shown.

[0035] Figure 11 The graph shows the long-term stability test curves of the Bi-GO double-doped WO3 electrochromic film in Example 3 at potentials of -0.3 / 0.5V. Detailed Implementation

[0036] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0037] Example 1

[0038] The Bi-GO dual-doped WO3 electrochromic thin film of this embodiment includes the following steps:

[0039] (1) Pretreatment of fluorine-doped tin oxide (FTO) glass substrate

[0040] An FTO glass substrate was ultrasonically cleaned for 15 minutes each with deionized water, anhydrous ethanol, and deionized water to remove surface organic matter, and the surface liquid was blown away. The dimensions of the FTO glass substrate were 3cm × 2cm.

[0041] (2) Preparation of Bi-GO-peroxytungstate sol

[0042] 15 g of tungstic acid (H₂WO₄) was dissolved in 100 mL of a 30% (w / w) hydrogen peroxide (H₂O₂) solution. The solution was stirred at 300 rpm for 4 days at room temperature and allowed to stand for 6 hours to obtain a clear and transparent peroxytungstic acid solution with a concentration of 0.3 M. Bismuth trioxide (Bi₂O₃) was added to the peroxytungstic acid solution to achieve a Bi:W atom ratio of 1:30. The solution with Bi₂O₃ was then sealed and heated in a water bath at 80 °C for 8 hours until the Bi₂O₃ was completely dissolved, yielding a Bi-peroxytungstic acid solution. 2 mL of the Bi-peroxytungstic acid solution was taken out and 200 μL of a 1 mg / mL GO nanosheet dispersion was added. The mixture was stirred and heated at 80 °C for 6 hours to form a homogeneous Bi-GO-peroxytungstic acid sol.

[0043] (3) Preparation of Bi-GO co-doped WO3 electrochromic thin films

[0044] The Bi-GO-peroxytungstic acid sol obtained in step (2) was spin-coated onto a pretreated FTO glass substrate at 1500 rpm for 40 s to form a film, followed by calcination at 300 °C for 2 h to obtain a Bi-GO double-doped WO3 electrochromic film. The structure of this Bi-GO double-doped WO3 electrochromic film is amorphous.

[0045] The Bi-GO dual-doped WO3 electrochromic film of Example 1 was prepared using the method described above.

[0046] The present invention provides a glass containing a Bi-GO dual-doped WO3 electrochromic film prepared in Example 1, which can be used in building doors and windows or glass curtain walls.

[0047] The scanning electron microscope (SEM) image of the Bi-GO dual-doped WO3 electrochromic thin film prepared in Example 1 is shown below. Figure 1 As shown.

[0048] The performance of the Bi-GO dual-doped WO3 electrochromic thin film prepared in Example 1 is as follows: Figures 2-5 As shown.

[0049] Example 2

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

[0051] An FTO glass substrate was ultrasonically cleaned for 15 minutes each with deionized water, anhydrous ethanol, and deionized water to remove surface organic matter, and the surface liquid was blown away. The dimensions of the FTO glass substrate were 3cm × 2cm.

[0052] (2) Preparation of Bi-GO-peroxytungstate sol

[0053] 15g of H₂WO₄ was dissolved in 100mL of 30% (w / w) H₂O₂. The solution was stirred at 300rpm for 4 days at room temperature and allowed to stand for 6 hours to obtain a clear and transparent peroxytungstic acid solution with a concentration of 0.3M. Bi₂O₃ was added to the peroxytungstic acid solution to achieve a Bi:W atom ratio of 1:30. The solution with added Bi₂O₃ was then sealed and heated in a water bath at 80℃ for 8 hours until the Bi₂O₃ was completely dissolved, yielding a Bi-peroxytungstic acid solution. 2mL of the Bi-peroxytungstic acid solution was taken out and 400μL of a 1mg / mL GO nanosheet dispersion was added. The mixture was stirred and heated at 80℃ for 6 hours to form a homogeneous Bi-GO-peroxytungstic acid sol.

[0054] (3) Preparation of Bi-GO co-doped WO3 electrochromic thin films

[0055] The Bi-GO-peroxytungstic acid sol obtained in step (2) was spin-coated onto a pretreated FTO glass substrate at 1500 rpm for 40 s to form a film, followed by calcination at 300 °C for 2 h to obtain a Bi-GO double-doped WO3 electrochromic film. The structure of this Bi-GO double-doped WO3 electrochromic film is amorphous.

[0056] The Bi-GO dual-doped WO3 electrochromic film in Example 2 was prepared using the method described above.

[0057] The present invention provides a glass containing a Bi-GO dual-doped WO3 electrochromic film prepared in Example 2, which can be used in building doors and windows or glass curtain walls.

[0058] The performance of the Bi-GO dual-doped WO3 electrochromic thin film prepared in Example 2 is as follows: Figures 6-8 As shown.

[0059] Example 3

[0060] The method for preparing the Bi-GO dual-doped WO3 electrochromic thin film in this embodiment includes the following steps:

[0061] (1) Pretreatment of fluorine-doped tin oxide (FTO) glass substrate

[0062] An FTO glass substrate was ultrasonically cleaned for 15 minutes each with deionized water, anhydrous ethanol, and deionized water to remove surface organic matter, and the surface liquid was blown away. The dimensions of the FTO glass substrate were 3cm × 2cm.

[0063] (2) Preparation of Bi-GO-peroxytungstate sol

[0064] 15g of H₂WO₄ was dissolved in 100mL of 30% (w / w) H₂O₂. The solution was stirred at 300rpm for 4 days at room temperature and allowed to stand for 6 hours to obtain a clear and transparent peroxytungstic acid solution with a concentration of 0.3M. Bi₂O₃ was added to the peroxytungstic acid solution to achieve a Bi:W atom ratio of 1:30. The solution was then sealed and heated in a water bath at 80℃ for 8 hours until the Bi₂O₃ was completely dissolved, yielding a Bi-peroxytungstic acid solution. 2mL of the Bi-peroxytungstic acid solution was taken out and 200μL of a 1mg / mL GO nanosheet dispersion was added. The mixture was stirred and heated at 80℃ for 6 hours to form a homogeneous Bi-GO-peroxytungstic acid sol.

[0065] (3) Preparation of Bi-GO co-doped WO3 electrochromic thin films

[0066] The Bi-GO-peroxytungstic acid sol obtained in step (2) was spin-coated onto a pretreated FTO glass substrate at 1500 rpm for 40 s to form a film, followed by calcination at 200 °C for 2 h to obtain a Bi-GO double-doped WO3 electrochromic film. The structure of this Bi-GO double-doped WO3 electrochromic film is amorphous.

[0067] The Bi-GO dual-doped WO3 electrochromic film in this embodiment was prepared using the method described above.

[0068] This invention provides a glass containing a Bi-GO dual-doped WO3 electrochromic film prepared in this embodiment, which can be used in building doors and windows or glass curtain walls.

[0069] The performance of the Bi-GO dual-doped WO3 electrochromic thin film prepared in Example 3 is as follows: Figures 9-11 As shown.

[0070] Example 4

[0071] The method for preparing the Bi-rGO dual-doped WO3 electrochromic thin film in this embodiment includes the following steps:

[0072] (1) Pretreatment of fluorine-doped tin oxide (FTO) glass substrate

[0073] An FTO glass substrate was ultrasonically cleaned for 15 minutes each with deionized water, anhydrous ethanol, and deionized water to remove surface organic matter, and the surface liquid was blown away. The dimensions of the FTO glass substrate were 3cm × 2cm.

[0074] (2) Preparation of Bi-rGO-peroxytungstate sol

[0075] 15g of H₂WO₄ was dissolved in 100mL of 30% (w / w) H₂O₂. The solution was stirred at 300rpm for 4 days at room temperature and allowed to stand for 6 hours to obtain a clear and transparent peroxytungstic acid solution with a concentration of 0.3M. Bi₂O₃ was added to the peroxytungstic acid solution to achieve a Bi:W atom ratio of 1:30. The solution was then sealed and heated in a water bath at 80℃ for 8 hours until the Bi₂O₃ was completely dissolved, yielding a Bi-peroxytungstic acid solution. 2mL of the Bi-peroxytungstic acid solution was taken out and 200μL of a 1mg / mL rGO nanosheet dispersion was added. The mixture was stirred and heated at 80℃ for 8 hours to form a homogeneous Bi-GO-peroxytungstic acid sol.

[0076] (3) Preparation of Bi-GO co-doped WO3 electrochromic thin films

[0077] The Bi-rGO-peroxytungstic acid sol obtained in step (2) was spin-coated onto a pretreated FTO glass substrate at 1500 rpm for 40 s to form a film, followed by calcination at 300 °C for 2 h to obtain a Bi-rGO double-doped WO3 electrochromic film. The structure of this Bi-rGO double-doped WO3 electrochromic film is amorphous.

[0078] The Bi-GO dual-doped WO3 electrochromic film in this embodiment was prepared using the method described above.

[0079] This invention provides a glass containing a Bi-rGO dual-doped WO3 electrochromic film prepared in this embodiment, which can be used in building doors and windows or glass curtain walls.

[0080] Example 5

[0081] The method for preparing the Bi-GO dual-doped WO3 electrochromic thin film in this embodiment includes the following steps:

[0082] (1) Pretreatment of fluorine-doped tin oxide (FTO) glass substrate

[0083] An FTO glass substrate was ultrasonically cleaned for 15 minutes each with deionized water, anhydrous ethanol, and deionized water to remove surface organic matter, and the surface liquid was blown away. The dimensions of the FTO glass substrate were 3cm × 2cm.

[0084] (2) Preparation of Bi-GO-peroxytungstate sol

[0085] 15g of H₂WO₄ was dissolved in 100mL of 30% (w / w) H₂O₂. The solution was stirred at 300rpm for 4 days at room temperature and allowed to stand for 6 hours to obtain a clear and transparent peroxytungstic acid solution with a concentration of 0.3M. Bismuth powder was added to the peroxytungstic acid solution to make the ratio of Bi atoms to W atoms in the solution 1:30. The peroxytungstic acid solution with added bismuth powder was then sealed and heated in a water bath at 80℃ for 8 hours until Bi₂O₃ was completely dissolved, resulting in a Bi-peroxytungstic acid solution. 2mL of the Bi-peroxytungstic acid solution was taken out and 200μL of GO nanosheet dispersion with a concentration of 4mg / mL was added. The mixture was stirred and heated at 60℃ for 10 hours to form a uniform Bi-GO-peroxytungstic acid sol.

[0086] (3) Preparation of Bi-GO co-doped WO3 electrochromic thin films

[0087] The Bi-GO-peroxytungstic acid sol obtained in step (2) was spin-coated onto a pretreated FTO glass substrate at 1500 rpm for 40 s to form a film, followed by calcination at 350 °C for 3 h to obtain a Bi-GO double-doped WO3 electrochromic film. The structure of this Bi-GO double-doped WO3 electrochromic film is amorphous.

[0088] The Bi-GO dual-doped WO3 electrochromic film in this embodiment was prepared using the method described above.

[0089] This invention provides a glass containing a Bi-GO dual-doped WO3 electrochromic film prepared in this embodiment, which can be used in building doors and windows or glass curtain walls.

[0090] Example 6

[0091] The method for preparing the Bi-GO dual-doped WO3 electrochromic thin film in this embodiment includes the following steps:

[0092] (1) Pretreatment of fluorine-doped tin oxide (FTO) glass substrate

[0093] An FTO glass substrate was ultrasonically cleaned for 15 minutes each with deionized water, anhydrous ethanol, and deionized water to remove surface organic matter, and the surface liquid was blown away. The dimensions of the FTO glass substrate were 3cm × 2cm.

[0094] (2) Preparation of Bi-GO-peroxytungstate sol

[0095] 15 g of H₂WO₄ was dissolved in 75 mL of 40% (w / w) H₂O₂. The solution was stirred at 300 rpm for 4 days at room temperature and allowed to stand for 6 hours to obtain a clear and transparent peroxytungstic acid solution with a concentration of 0.4 M. Bismuth nitrate was added to the peroxytungstic acid solution to achieve a Bi:W atom ratio of 1:30. The peroxytungstic acid solution with bismuth nitrate was then sealed and heated in a water bath at 60 °C for 12 hours until the bismuth nitrate was completely dissolved, yielding a Bi-peroxytungstic acid solution. 2 mL of the Bi-peroxytungstic acid solution was taken out and 800 μL of a 0.5 mg / mL rGO nanosheet dispersion was added. The mixture was stirred and heated at 50 °C for 12 hours to form a homogeneous Bi-GO-peroxytungstic acid sol.

[0096] (3) Preparation of Bi-GO co-doped WO3 electrochromic thin films

[0097] The Bi-GO-peroxytungstic acid sol obtained in step (2) was spin-coated onto a pretreated FTO glass substrate at 1500 rpm for 40 s to form a film, followed by calcination at 600 °C for 5 h to obtain a Bi-GO double-doped WO3 electrochromic film. The structure of this Bi-GO double-doped WO3 electrochromic film is a crystalline structure.

[0098] The Bi-GO dual-doped WO3 electrochromic film in this embodiment was prepared using the method described above.

[0099] This invention provides a glass containing a Bi-GO dual-doped WO3 electrochromic film prepared in this embodiment, which can be used in building doors and windows or glass curtain walls.

[0100] Example 7

[0101] The method for preparing the Bi-GO dual-doped WO3 electrochromic thin film in this embodiment includes the following steps:

[0102] (1) Pretreatment of fluorine-doped tin oxide (FTO) glass substrate

[0103] An FTO glass substrate was ultrasonically cleaned for 15 minutes each with deionized water, anhydrous ethanol, and deionized water to remove surface organic matter, and the surface liquid was blown away. The dimensions of the FTO glass substrate were 3cm × 2cm.

[0104] (2) Preparation of Bi-GO-peroxytungstate sol

[0105] 15g of H₂WO₄ was dissolved in 150mL of 15% (w / w) H₂O₂. The solution was stirred at 300rpm for 4 days at room temperature and allowed to stand for 6 hours to obtain a clear and transparent peroxytungstic acid solution with a concentration of 0.2M. Bismuth trioxide was added to the peroxytungstic acid solution to achieve a Bi:W atom ratio of 1:30. The solution was then sealed and heated at 100℃ for 4 hours until the bismuth trioxide was completely dissolved, yielding a Bi-peroxytungstic acid solution. 2mL of the Bi-peroxytungstic acid solution was taken out and 200μL of a 2mg / mL GO nanosheet dispersion was added. The mixture was stirred and heated at 100℃ for 4 hours to form a homogeneous Bi-GO-peroxytungstic acid sol.

[0106] (3) Preparation of Bi-GO co-doped WO3 electrochromic thin films

[0107] The Bi-GO-peroxytungstic acid sol obtained in step (2) was spin-coated onto a pretreated FTO glass substrate at 1500 rpm for 40 s to form a film, followed by calcination at 200 °C for 5 h to obtain a Bi-GO double-doped WO3 electrochromic film. The structure of this Bi-GO double-doped WO3 electrochromic film is amorphous.

[0108] The Bi-GO dual-doped WO3 electrochromic film in this embodiment was prepared using the method described above.

[0109] This invention provides a glass containing a Bi-GO dual-doped WO3 electrochromic film prepared in this embodiment, which can be used in building doors and windows or glass curtain walls.

[0110] Experimental Example 1

[0111] The Bi-GO dual-doped WO3 electrochromic film prepared in Example 1 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 results are as follows: Figures 2-5 As shown. From Figure 2It can be seen that the Bi-GO dual-doped WO3 electrochromic film prepared in Example 1, with 0.5M H2SO4 solution as the electrolyte and a wavelength of 630nm, exhibits an 85% change in transmittance between the -0.3V colored state and the -0.5V bleached state. This indicates that the Bi-GO dual-doped WO3 electrochromic film prepared in Example 1 possesses a wider optical modulation range and better stability. Figure 3 and Figure 4 As can be seen, the Bi-GO dual-doped WO3 electrochromic film prepared in Example 1 has a very short fading and coloring time, with coloring and fading times of 1.8 s and 1.8 s respectively, and a coloring efficiency of 65.9 cm⁻¹. 2 / C. From Figure 5 It can be seen that the Bi-GO dual-doped WO3 electrochromic film prepared in Example 1 remains stable after more than 10,000 cycles.

[0112] Experiment Example 2

[0113] The Bi-GO dual-doped WO3 electrochromic film prepared in Example 2 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 6-8 As shown. From Figure 6 It can be seen that the Bi-GO dual-doped WO3 electrochromic film prepared in Example 2, with 0.5M H2SO4 solution as the electrolyte and a wavelength of 630nm, exhibits a 69.5% change in transmittance between the -0.3V colored state and the -0.5V bleached state compared to the Bi-GO dual-doped WO3 electrochromic film prepared in Example 1. Therefore, the Bi-GO dual-doped WO3 electrochromic film prepared in Example 2 possesses a wider optical modulation range. Figure 7 and Figure 8 As can be seen, the Bi-GO dual-doped WO3 electrochromic film prepared in Example 2 has very short fading and coloring times, with coloring and fading times of 3 s and 0.9 s respectively, and a coloring efficiency of 51.11 cm⁻¹. 2 / C.

[0114] Experimental Example 3

[0115] The Bi-GO dual-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 9-11 As shown. From Figure 9 It can be seen that the Bi-GO dual-doped WO3 electrochromic film prepared in Example 3, with 0.5M H2SO4 solution as the electrolyte and a wavelength of 630nm, exhibits an 85% change in transmittance between the -0.3V colored state and the -0.5V bleached state compared to the Bi-GO dual-doped WO3 electrochromic film prepared in Example 1. Therefore, the Bi-GO dual-doped WO3 electrochromic film prepared in Example 3 possesses a wider optical modulation range and better stability. Figure 10 It can be seen that the Bi-GO dual-doped WO3 electrochromic film prepared in Example 3 has a very short fading and coloring time, with coloring and fading times of 2.4 s and 1.5 s, respectively. Figure 11 It can be seen that the Bi-GO dual-doped WO3 electrochromic film prepared in Example 3 remained stable after more than 5760 cycles, with each cycle lasting 10 seconds and a test duration of 960 minutes.

[0116] As can be seen from Experiments 1, 2, and 3, the prepared Bi-GO double-doped WO3 electrochromic films have three major advantages: (1) Bi doping increases the interlayer spacing and induces the material to tend towards the (002) direction, reducing the diffusion barrier of protons; (2) Graphene-based materials have higher conductivity, which can promote the transfer of electrons in WO3-based films; (3) Graphene-based materials contain various oxygen-containing functional groups, such as hydroxyl, carboxyl, and ketone groups. These functional groups improve the hydrophilicity of graphene oxide, enabling it to have significant interfacial interactions with polar substrates. Combined with aging, a uniform sol can be obtained, and then a film with a uniform structure and strong adhesion to the substrate can be prepared by spin coating. These advantages enable the Bi-GO double-doped WO3 electrochromic films to have accelerated charge transport dynamics, promote the transfer of electrons in the material and the insertion / extraction process of protons in the lattice, and thus enable the films to exhibit excellent light modulation range response speed. In addition, the sheet-like structure of GO is conducive to the adhesion of WO3 materials and the exposure of more active sites. The loose structure of the film and its strong adhesion to the substrate give it excellent electrochromic cycling stability.

Claims

1. A method for preparing a Bi-GO dual-doped WO3 electrochromic thin film, characterized in that, Includes the following steps: Step 1): Dissolve tungstic acid in hydrogen peroxide solution to obtain peroxytungstic acid solution. Add a bismuth-containing substance to the peroxytungstic acid solution. After the bismuth-containing substance dissolves, obtain Bi-peroxytungstic acid solution. Step 2): Add graphene-based nanosheet dispersion to the Bi-peroxytungstic acid solution obtained in Step 1), stir and heat to form a uniform Bi-GO-peroxytungstic acid sol; Step 3): Spin-coat the Bi-GO-peroxytungstic acid sol obtained in Step 2) onto a conductive glass substrate, and then calcine it to obtain the final product; The preparation method of Bi-GO-peroxytungstic acid sol in step 2) is as follows: after adding the graphene-based material nanosheet dispersion to the Bi-peroxytungstic acid solution, stir and heat at 50-100 °C for 4-12 h to obtain the solution. The mass ratio of the graphene-based material to tungstic acid is 0.0001 to 0.03:1, and the concentration of the graphene-based material nanosheet dispersion is 0.5 to 8 mg / mL. The preparation method of the Bi-peroxytungstic acid solution is as follows: after adding the bismuth-containing substance to the peroxytungstic acid solution, the solution is sealed and heated at 60-100 °C for 4-12 h to obtain the solution; the bismuth-containing substance is one or more of bismuth trioxide, bismuth powder, or bismuth nitrate; the ratio of tungsten atoms to bismuth atoms in the Bi-peroxytungstic acid solution is 1:30; each g of the tungstic acid corresponds to 5-10 mL of hydrogen peroxide solution; and the volume ratio of the Bi-peroxytungstic acid solution to the graphene-based nanosheet dispersion is 10-2:

1. The mass percentage concentration of the hydrogen peroxide solution in step 1) is 15-50%, and the molar concentration of the peroxytungstic acid solution is 0.1-1 M.

2. The method for preparing the Bi-GO dual-doped WO3 electrochromic thin film according to claim 1, characterized in that, Step 2) The graphene-based material is graphene oxide or graphene oxide-reduction.

3. The method for preparing the Bi-GO dual-doped WO3 electrochromic thin film according to claim 1, characterized in that, Step 3) The conductive glass substrate is a fluorine-doped tin oxide glass substrate, and the calcination temperature is 100-600 °C, and the calcination time is 0-6 h.

4. A Bi-GO dual-doped WO3 electrochromic thin film, characterized in that, The film was prepared using the method described in claim 1 for preparing Bi-GO dual-doped WO3 electrochromic thin films.

5. The Bi-GO dual-doped WO3 electrochromic thin film according to claim 4, characterized in that, The structure of the Bi-GO double-doped WO3 electrochromic film is amorphous.

6. A type of glass, characterized in that, The glass contains the Bi-GO dual-doped WO3 electrochromic film as described in claim 4, and the glass is used in building doors and windows or glass curtain walls.

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