Ultraviolet-shielding color-dynamically-adjustable VO2 intelligent window and preparation method thereof

Abstract

The invention discloses an ultraviolet-shielding color-dynamically-adjustable VO2 intelligent window and a preparation method thereof, and relates to a color-dynamically-adjustable intelligent window and a preparation method thereof. The problem that an existing intelligent window cannot have the ultraviolet shielding function and the dynamic color adjustment function at the same time is solved. The VO2 intelligent window is sequentially composed of a transparent substrate, a visible wave band color regulation and control layer and a VO2 functional layer from bottom to top. The preparation method comprises the following steps: 1, cleaning the substrate; 2, preparing a visible wave band color regulation and control layer; 3, preparing a VO2 thin film; and 4, carrying out VO2 film post-treatment. The invention is used for the ultraviolet-shielding color-dynamically-adjustable VO2 intelligent window and the preparation method thereof.

Description

Technical Field

[0001] The invention relates to a smart window with dynamically adjustable color and a preparation method thereof. Background Art

[0002] Windows are the main way for buildings to exchange heat with the external environment, and their energy share in the total heat exchange process is as high as 50%. Smart windows can dynamically adjust the transmittance, reflectivity and absorptivity of sunlight under the stimulation of the external environment or human control, thereby effectively reducing the energy consumption of buildings. In addition, long-term exposure to high ultraviolet light environments can cause significant damage to human health. The main hazards of ultraviolet rays include skin damage, increased risk of skin cancer, and damage to the eyes. At the same time, ultraviolet rays can also cause indoor furniture and floors to fade and age. Therefore, smart windows with ultraviolet shielding functions play a vital role in maintaining human health and creating a comfortable living environment.

[0003] VO2 is a thermochromic material with unique metal-insulator phase transition characteristics. During the phase transition from the low-temperature monoclinic phase to the high-temperature rutile phase, its optical and electrical properties will undergo a sudden change. Specifically, VO2 film exhibits high transmittance in the infrared band at low temperatures and high reflectivity at high temperatures, which is very suitable for smart window applications. However, due to the strong intra-band and inter-band absorption of the metallic and semiconductor states of VO2 in the short-wave range, the VO2 film is brown-yellow and lacks a good user experience as a smart window.

[0004] Therefore, realizing a VO2 smart window that has both UV shielding function and dynamically adjustable color is an urgent problem that needs to be solved in the existing technology. Summary of the invention

[0005] The present invention aims to solve the problem that the existing smart windows cannot have both ultraviolet shielding function and dynamic color adjustment, and further provide a VO2 smart window with ultraviolet shielding and dynamic color adjustment and a preparation method thereof.

[0006] A UV shielding VO2 smart window with dynamically adjustable color, which is composed of a transparent substrate, a visible band color regulating layer and a VO2 functional layer from bottom to top;

[0007] The thickness of the VO2 functional layer is 20nm-400nm; the material of the VO2 functional layer is VO2 or element-doped VO2.

[0008] A method for preparing a VO2 smart window with dynamically adjustable ultraviolet shielding color is carried out according to the following steps:

[0009] 1. Substrate cleaning:

[0010] Polishing and cleaning the transparent substrate to obtain a pre-treated substrate;

[0011] 2. Preparation of visible band color control layer:

[0012] A visible band color control layer is prepared on one side of the pretreated substrate by magnetron sputtering, electron beam evaporation, atomic layer deposition, molecular beam epitaxy or chemical vapor deposition;

[0013] 3. VO2 thin film preparation:

[0014] A VO2 thin film is prepared on the visible band color control layer by evaporation, magnetron sputtering, pulsed laser deposition, electron beam evaporation, sol-gel method, hydrothermal method, atomic layer deposition or molecular beam epitaxy to obtain a multilayer composite film;

[0015] 4. VO2 film post-processing:

[0016] The multilayer composite film is placed in a tubular furnace and kept warm at an argon flow rate of 90 sccm to 120 sccm and a temperature of 400°C to 550°C. Finally, it is naturally cooled to room temperature, thereby completing the preparation method of the UV-shielding color dynamically adjustable VO2 smart window.

[0017] The beneficial effects of the present invention are:

[0018] The peak transmittance of Si film in the visible band will red-shift as the thickness increases, so Si films of different thicknesses present different colors. At the same time, due to the interference between Si and VO2, the smart window also presents different colors before and after the VO2 phase change. The present invention is based on the phase change material VO2, and utilizes the characteristics of sudden changes in its optical properties before and after the phase change, combined with Si with certain absorption in the ultraviolet and visible bands, to prepare a VO2-based ultraviolet blocking and color-adjustable thermochromic smart window. Changing the thickness of Si can achieve static adjustment of the color of the smart window, and at the same time, the dynamic regulation of the color of the smart window with temperature can be achieved with the phase transition of VO2. The VO2 phase change temperature can be adjusted by doping with different concentrations of W elements, and the infrared emissivity at different ambient temperatures can be regulated dynamically.

[0019] (1) The smart window prepared by the present invention can achieve low transmittance in the ultraviolet band (200nm-380nm), static and dynamic color adjustment in the visible band, and excellent thermal regulation ability in the sunlight band (280nm-2500nm);

[0020] (2) The smart window prepared by the present invention has the characteristics of large color control range, high transmittance at low temperature, high reflectivity at high temperature, adjustable phase change temperature and rapid response, and can be applied to different regions to achieve building beautification and energy saving.

[0021] (3) The preparation process of the present invention has the characteristics of diversity, simplicity, low cost, high repeatability and large-scale preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The schematic diagram of the structure of the VO2 smart window with dynamically adjustable ultraviolet shielding color of the present invention, 1 is a transparent substrate, 2 is a visible band color regulating layer, and 3 is a VO2 functional layer;

[0023] Figure 2 The transmission spectra of the UV shielding color dynamically adjustable VO2 smart windows prepared in Examples 1 to 10 and the comparative experiment;

[0024] Figure 3 The reflective chromaticity diagram of the VO2 smart window with dynamically adjustable ultraviolet shielding color prepared in Examples 1 to 10 and the comparative experiment. DETAILED DESCRIPTION

[0025] Specific implementation method 1: Combination Figure 1 Specifically describing the present embodiment, the present embodiment is a UV shielding color dynamically adjustable VO2 smart window, which is composed of a transparent substrate, a visible band color regulating layer and a VO2 functional layer from bottom to top;

[0026] The thickness of the VO2 functional layer is 20nm-400nm; the material of the VO2 functional layer is VO2 or element-doped VO2.

[0027] This specific implementation method constructs a geometric model based on the complex refractive index of the transparent substrate, the color control layer and the VO2 layer; based on the constructed geometric model, the spectral transmittance is simulated; based on the visual standard luminous efficiency function and the solar radiation spectrum, the spectral transmittance is converted into the optical properties of the smart window; by evaluating the optical properties of the smart window, the required thickness and preparation parameters of the color control layer and VO2 layer are determined.

[0028] The beneficial effects of this embodiment are:

[0029] The peak transmittance of Si film in the visible band will red-shift as the thickness increases, so Si films of different thicknesses show different colors. At the same time, due to the interference between Si and VO2, the smart window also shows different colors before and after the VO2 phase change. This embodiment is based on the phase change material VO2, and utilizes the characteristics of sudden changes in its optical properties before and after the phase change, combined with Si with certain absorption in the ultraviolet and visible bands, to prepare a VO2-based ultraviolet-blocking, color-adjustable thermochromic smart window. Changing the thickness of Si can achieve static adjustment of the color of the smart window, and at the same time, the dynamic regulation of the color of the smart window with temperature can be achieved with the phase transition of VO2. The VO2 phase change temperature can be adjusted by doping with different concentrations of W elements, and the infrared emissivity at different ambient temperatures can be regulated dynamically.

[0030] (1) The smart window prepared in this embodiment can achieve low transmittance in the ultraviolet band (200nm-380nm), static and dynamic color adjustment in the visible band, and excellent thermal regulation capability in the sunlight band (280nm-2500nm);

[0031] (2) The smart window prepared in this embodiment has the characteristics of large color control range, high transmittance at low temperature, high reflectivity at high temperature, adjustable phase change temperature and rapid response, and can be applied to different regions to achieve building beautification and energy saving.

[0032] (3) The preparation process of this embodiment has the characteristics of diversity, simplicity, low cost, high repeatability and large-area preparation.

[0033] Specific implementation method 2: This implementation method is different from specific implementation method 1 in that: the transmittance of the transparent substrate in the solar band is above 55%; the transparent substrate is quartz glass, soda-lime glass, CaF2, sapphire, polydimethylsiloxane or polymethyl methacrylate. The rest is the same as specific implementation method 1.

[0034] Specific implementation method three: This implementation method is different from specific implementation method one or two in that: the element-doped VO2 is W-doped VO2, Mo-doped VO2, Eu-doped VO2, F-doped VO2, W-Mo co-doped VO2 or F-Mo co-doped VO2. The rest is the same as specific implementation method one or two.

[0035] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that the visible band color control layer is Si, Ge, TiO2, CeO2 or Ga2O3. Other aspects are the same as specific embodiments 1 to 3.

[0036] Specific implementation method 5: This implementation method is different from specific implementation methods 1 to 4 in that the thickness of the visible band color control layer is 10nm to 300nm. It is the same as specific implementation methods 1 to 4.

[0037] Specific implementation method 6: This implementation method is a method for preparing a UV shielding VO2 smart window with dynamically adjustable color, which is carried out according to the following steps:

[0038] 1. Substrate cleaning:

[0039] Polishing and cleaning the transparent substrate to obtain a pre-treated substrate;

[0040] 2. Preparation of visible band color control layer:

[0041] A visible band color control layer is prepared on one side of the pretreated substrate by magnetron sputtering, electron beam evaporation, atomic layer deposition, molecular beam epitaxy or chemical vapor deposition;

[0042] 3. VO2 thin film preparation:

[0043] A VO2 thin film is prepared on the visible band color control layer by evaporation, magnetron sputtering, pulsed laser deposition, electron beam evaporation, sol-gel method, hydrothermal method, atomic layer deposition or molecular beam epitaxy to obtain a multilayer composite film;

[0044] 4. VO2 film post-processing:

[0045] The multilayer composite film is placed in a tubular furnace and kept warm at an argon flow rate of 90 sccm to 120 sccm and a temperature of 400°C to 550°C. Finally, it is naturally cooled to room temperature, thereby completing the preparation method of the UV-shielding color dynamically adjustable VO2 smart window.

[0046] Specific embodiment 7: This embodiment is different from specific embodiment 6 in that: when step 2 uses radio frequency magnetron sputtering to prepare a Si layer on one side of the pretreated substrate, it is specifically carried out in the following steps: vacuumizing to 1×10 -3 Pa~2×10 -3 Pa, with Si target as target material, then sputtering is performed on one side of the pretreated substrate to obtain a Si layer under the conditions of RF power of 100W-200W, pressure of 0.4Pa-1.0Pa, argon flow of 80sccm-90sccm and substrate temperature of 50°C-200°C. The rest is the same as the sixth embodiment.

[0047] Specific embodiment 8: This embodiment differs from either specific embodiment 6 or 7 in that: when high-energy pulsed magnetron sputtering is used in step 3 to prepare a VO2 thin film on the visible band color control layer, the steps are specifically performed as follows: vacuuming to 4×10 -4 Pa~1×10 -3 Pa, using a metal V target or a W-doped metal V target as a target material, and then preparing a VO2 thin film on a visible band color control layer under the conditions of a frequency of 350 Hz to 400 Hz, a pulse width of 45 μs to 50 μs, a power of 180 W to 200 W, a high energy pulse voltage of 450 V to 510 V, a pressure of 0.4 Pa to 1.0 Pa, an argon flow rate of 80 sccm to 85 sccm, an oxygen flow rate of 0.8 sccm to 1.4 sccm, and a substrate temperature of 200 ° C to 550 ° C, to obtain a multilayer composite thin film. The rest is the same as the sixth or seventh specific implementation.

[0048] Specific embodiment 9: This embodiment differs from any one of specific embodiments 6 to 8 in that in step 4, the temperature is raised to 400° C. to 550° C. under the conditions of an argon gas flow rate of 90 sccm to 120 sccm and a heating rate of 1° C. / min to 5° C. / min. The rest is the same as specific embodiments 6 to 8.

[0049] Specific embodiment 10: This embodiment differs from specific embodiments 6 to 9 in that in step 4, the temperature is kept at 400° C. to 550° C. and the argon gas flow rate is 90 sccm to 120 sccm. The other steps are the same as those of specific embodiments 6 to 9.

[0050] The following examples are used to verify the beneficial effects of the present invention:

[0051] Embodiment 1:

[0052] A UV shielding VO2 smart window with dynamically adjustable color, which is composed of a transparent substrate, a visible band color regulating layer and a VO2 functional layer from bottom to top;

[0053] The thickness of the VO2 functional layer is 50nm; the material of the VO2 functional layer is VO2;

[0054] The transparent substrate is quartz glass.

[0055] The visible band color regulating layer is a Si layer.

[0056] The thickness of the visible band color regulation layer is 10 nm.

[0057] The preparation method of the above-mentioned UV shielding color dynamically adjustable VO2 smart window is carried out according to the following steps:

[0058] 1. Substrate cleaning:

[0059] Polishing and cleaning the transparent substrate to obtain a pre-treated substrate;

[0060] 2. Preparation of visible band color control layer:

[0061] Using radio frequency magnetron sputtering, first evacuate to 1×10 -3 Pa, with Si target as the target material, then sputtering on one side of the pretreated substrate to obtain a visible band color regulation layer, i.e., Si layer, under the conditions of RF power of 150 W, pressure of 0.4 Pa, argon gas flow rate of 80 sccm and substrate temperature of 200 ° C;

[0062] 3. VO2 thin film preparation:

[0063] Using high-energy pulse magnetron sputtering, first evacuate to 4×10 -4 Pa, using a metal V target as a target material, and then preparing a VO2 thin film on a visible band color control layer under the conditions of a frequency of 400 Hz, a pulse width of 50 μs, a power of 180 W, a high-energy pulse voltage of 510 V, a pressure of 0.85 Pa, an argon flow rate of 80 sccm, an oxygen flow rate of 0.8 sccm and a substrate temperature of 200 ° C to obtain a multilayer composite film;

[0064] 4. VO2 film post-processing:

[0065] The multilayer composite film is placed in a tubular furnace, heated to 400°C at an argon flow rate of 100 sccm and a heating rate of 1°C / min, kept warm for 5 hours at an argon flow rate of 100 sccm and a temperature of 400°C, and finally naturally cooled to room temperature, thereby completing the preparation method of the UV-shielding color dynamically adjustable VO2 smart window.

[0066] The spectral transmittance of the UV shielding color dynamically adjustable VO2 smart window prepared in Example 1 in the wavelength range of 200nm to 2500nm at temperatures of 30°C and 90°C was calculated to obtain a transmittance of less than 9% in the ultraviolet band (200nm to 380nm), a transmittance of 40.62% in the visible light band (380nm to 780nm), and a thermal regulation capacity of 2.33% in the sunlight band (280nm to 2500nm). When the temperature is lower than its phase transition temperature, its color coordinates are (0.41642, 0.43096) and when it is higher than its phase transition temperature, its color coordinates are (0.36419, 0.39675).

[0067] Embodiment 2: This embodiment is different from Embodiment 1 in that the thickness of the visible band color control layer is 20 nm. Other aspects are the same as Embodiment 1.

[0068] The spectral transmittance of the ultraviolet shielding VO2 smart window with dynamically adjustable color prepared in Example 2 in the wavelength range of 200nm to 2500nm at temperatures of 30°C and 90°C, and it is calculated that the transmittance in the ultraviolet band (200nm to 380nm) is less than 7%, the transmittance in the visible light band (380nm to 780nm) is 43.95%, and the thermal regulation ability in the sunlight band (280nm to 2500nm) is 3.24%. When the temperature is lower than its phase transition temperature, the color coordinates are (0.38827, 0.28563), and when it is higher than its phase transition temperature, the color coordinates are (0.44847, 0.4621).

[0069] Embodiment 3: This embodiment is different from Embodiment 1 in that the thickness of the visible band color control layer is 30 nm. Other aspects are the same as Embodiment 1.

[0070] The spectral transmittance of the ultraviolet shielding VO2 smart window with dynamically adjustable color prepared in Example 3 in the wavelength range of 200nm to 2500nm at temperatures of 30°C and 90°C, and it is calculated that the transmittance in the ultraviolet band (200nm to 380nm) is less than 7%, the transmittance in the visible light band (380nm to 780nm) is 43.34%, and the thermal regulation ability in the sunlight band (280nm to 2500nm) is 4.17%. When the temperature is lower than its phase transition temperature, the color coordinates are (0.16224, 0.0176), and when it is higher than its phase transition temperature, the color coordinates are (0.49934, 0.40322).

[0071] Embodiment 4: This embodiment is different from Embodiment 1 in that the thickness of the visible band color regulating layer is 40 nm. Other aspects are the same as Embodiment 1.

[0072] The spectral transmittance of the ultraviolet shielding VO2 smart window with dynamically adjustable color prepared in Example 4 in the wavelength range of 200nm to 2500nm at temperatures of 30°C and 90°C, and it is calculated that the transmittance in the ultraviolet band (200nm to 380nm) is less than 5%, the transmittance in the visible light band (380nm to 780nm) is 39.81%, the thermal regulation ability in the sunlight band (280nm to 2500nm) is 5.11%, and when the temperature is lower than its phase transition temperature, the color coordinates are (0.18546, 0.21528), and when it is higher than its phase transition temperature, the color coordinates are (0.34848, 0.18484).

[0073] Embodiment 5: This embodiment is different from Embodiment 1 in that the thickness of the visible band color control layer is 50 nm. Other aspects are the same as Embodiment 1.

[0074] The spectral transmittance of the ultraviolet shielding VO2 smart window with dynamically adjustable color prepared in Example 5 in the wavelength range of 200nm to 2500nm at temperatures of 30°C and 90°C, and it is calculated that the transmittance in the ultraviolet band (200nm to 380nm) is less than 3%, the transmittance in the visible light band (380nm to 780nm) is 36.51%, and the thermal regulation ability in the sunlight band (280nm to 2500nm) is 6.12%. When the temperature is lower than its phase transition temperature, the color coordinates are (0.22826, 0.34893), and when the temperature is higher than its phase transition temperature, the color coordinates are (0.2253, 0.20586).

[0075] Embodiment 6: This embodiment is different from Embodiment 1 in that the thickness of the visible band color control layer is 60 nm. The rest is the same as Embodiment 1.

[0076] The spectral transmittance of the ultraviolet shielding VO2 smart window with dynamically adjustable color prepared in Example 6 in the wavelength range of 200nm to 2500nm at temperatures of 30°C and 90°C, and it was calculated that the transmittance in the ultraviolet band (200nm to 380nm) was less than 3%, the transmittance in the visible light band (380nm to 780nm) was 35.19%, and the thermal regulation ability in the sunlight band (280nm to 2500nm) was 7.06%. When the temperature is lower than its phase transition temperature, the color coordinates are (0.31144, 0.42652), and when it is higher than its phase transition temperature, the color coordinates are (0.27084, 0.41197).

[0077] Embodiment 7: This embodiment is different from Embodiment 1 in that the thickness of the visible band color control layer is 70 nm. The rest is the same as Embodiment 1.

[0078] The spectral transmittance of the ultraviolet shielding VO2 smart window with dynamically adjustable color prepared in Example 7 in the wavelength range of 200nm to 2500nm at temperatures of 30°C and 90°C, and it was calculated that the transmittance in the ultraviolet band (200nm to 380nm) was less than 2%, the transmittance in the visible light band (380nm to 780nm) was 35.96%, the thermal regulation ability in the sunlight band (280nm to 2500nm) was 7.65%, and when the temperature was lower than its phase transition temperature, the color coordinates were (0.35387, 0.37659), and when the temperature was higher than its phase transition temperature, the color coordinates were (0.35557, 0.49992).

[0079] Embodiment 8: This embodiment is different from Embodiment 1 in that the thickness of the visible band color control layer is 80 nm. Other aspects are the same as Embodiment 1.

[0080] The spectral transmittance of the ultraviolet shielding VO2 smart window with dynamically adjustable color prepared in Example 8 in the wavelength range of 200nm to 2500nm at temperatures of 30°C and 90°C was measured, and it was calculated that the transmittance in the ultraviolet band (200nm to 380nm) was less than 1.5%, the transmittance in the visible light band (380nm to 780nm) was 37.83%, the thermal regulation ability in the sunlight band (280nm to 2500nm) was 7.81%, and when the temperature was lower than its phase transition temperature, the color coordinates were (0.36329, 0.29999), and when it was higher than its phase transition temperature, the color coordinates were (0.42133, 0.47307).

[0081] Embodiment 9: This embodiment is different from Embodiment 1 in that the thickness of the visible band color regulating layer is 90 nm. The rest is the same as Embodiment 1.

[0082] The spectral transmittance of the ultraviolet shielding VO2 smart window with dynamically adjustable color prepared in Example 9 in the wavelength range of 200nm to 2500nm at temperatures of 30°C and 90°C, and it was calculated that the transmittance in the ultraviolet band (200nm to 380nm) was less than 1%, the transmittance in the visible light band (380nm to 780nm) was 39.21%, the thermal regulation capacity in the sunlight band (280nm to 2500nm) was 7.74%, and when the temperature was lower than its phase transition temperature, the color coordinates were (0.35422, 0.25116), and when the temperature was higher than its phase transition temperature, the color coordinates were (0.4434, 0.37798).

[0083] Embodiment 10: This embodiment is different from Embodiment 1 in that the thickness of the visible band color control layer is 100 nm. The rest is the same as Embodiment 1.

[0084] The spectral transmittance of the ultraviolet shielding VO2 smart window with dynamically adjustable color prepared in Example 10 in the wavelength range of 200nm to 2500nm at temperatures of 30°C and 90°C, and it was calculated that the transmittance in the ultraviolet band (200nm to 380nm) was less than 0.6%, the transmittance in the visible light band (380nm to 780nm) was 38.91%, the thermal regulation ability in the sunlight band (280nm to 2500nm) was 7.60%, and when the temperature was lower than its phase transition temperature, the color coordinates were (0.31328, 0.26065), and when it was higher than its phase transition temperature, the color coordinates were (0.43162, 0.28853).

[0085] Comparative experiment: The difference between this comparative experiment and the first embodiment is that the thickness of the visible band color regulation layer is 0 nm. The rest is the same as the first embodiment.

[0086] The spectral transmittance of the VO2 smart window prepared in the comparative experiment was measured in the wavelength range of 200nm to 2500nm at temperatures of 30℃ and 90℃, and it was calculated that the transmittance in the ultraviolet band (200nm to 380nm) was >12%, the transmittance in the visible light band (380nm to 780nm) was 41.62%, and the thermal regulation ability in the sunlight band (280nm to 2500nm) was 2.33%. When the temperature is lower than its phase transition temperature, the color coordinates are (0.32441, 0.35853), and when it is higher than its phase transition temperature, the color coordinates are (0.32742, 0.34268).

[0087] Figure 2 The transmission spectra of the UV shielding color dynamically adjustable VO2 smart window prepared in Examples 1 to 10 and comparative experiments; in the figure, SiO2 / Si / VO2(M) represents VO2 before phase change, SiO2 / Si / VO2(R) represents after phase change, and 0mm to 100nm in the figure represents the thickness change of the color regulation layer Si in the visible band. As can be seen from the figure, the smart window has a high visible transmittance, and the transmission spectrum of the smart window before and after the vanadium oxide phase change has a significant difference, and has considerable thermal regulation ability. As the thickness of the color regulation layer increases, the transmission peak of the smart window in the visible band gradually redshifts, indicating that changing the thickness of the color regulation layer can achieve static regulation of the color of the UV shielding color dynamically adjustable VO2 smart window.

[0088] Figure 3 The reflective chromaticity diagram of the UV shielding VO2 smart window with dynamically adjustable color prepared in Examples 1 to 10 and the comparative experiment; in the figure, M in M-0nm to M-100nm represents before phase change, R in R-0nm to R-100nm represents after phase change, and 0nm to 100nm represents the thickness of the color control layer in the visible band. It can be seen from the figure that adjusting the thickness of the color control layer can realize the static color control of the smart window across the color gamut, which is similar to Figure 2 The predicted results are consistent. At the same time, by comparing the chromaticity diagram of VO2 before and after the phase change under the same color regulation layer thickness, it can be found that the color of the VO2 smart window with dynamically adjustable ultraviolet shielding color has achieved significant color changes before and after the phase change, and even changes in warm and cold tones.

[0089] Depend on Figure 2 and Figure 3 It can be seen that by adjusting the Si thickness, the color of the smart window can be statically controlled across the color gamut. By comparing the chromaticity diagrams of VO2(M) and VO2(R) under the same Si thickness, it can be observed that the color of the smart window can be significantly dynamically controlled with temperature changes.

Claims

1. A VO2 smart window with dynamically adjustable ultraviolet shielding color, characterized in that It consists of a transparent substrate, a visible band color regulation layer, and a VO2 functional layer from bottom to top; The thickness of the VO2 functional layer is 20nm-400nm; the material of the VO2 functional layer is VO2 or element-doped VO2.

2. The VO2 smart window with dynamically adjustable ultraviolet shielding color according to claim 1, characterized in that The transmittance of the transparent substrate in the solar band is above 55%; the transparent substrate is quartz glass, soda-lime glass, CaF2, sapphire, polydimethylsiloxane or polymethyl methacrylate.

3. The VO2 smart window with dynamically adjustable ultraviolet shielding color according to claim 1, characterized in that The element-doped VO2 is W-doped VO2, Mo-doped VO2, Eu-doped VO2, F-doped VO2, W-Mo co-doped VO2 or F-Mo co-doped VO2.

4. The VO2 smart window with dynamically adjustable ultraviolet shielding color according to claim 1, characterized in that The visible band color regulation layer is Si, Ge, TiO2, CeO2 or Ga2O3.

5. The VO2 smart window with dynamically adjustable ultraviolet shielding color according to claim 4, characterized in that The thickness of the visible band color regulation layer is 10nm to 300nm.

6. The method for preparing a VO2 smart window with dynamically adjustable ultraviolet shielding color as claimed in claim 1, characterized in that It is carried out in the following steps:

1. Substrate cleaning: Polishing and cleaning the transparent substrate to obtain a pre-treated substrate; 2. Preparation of visible band color control layer: A visible band color control layer is prepared on one side of the pretreated substrate by magnetron sputtering, electron beam evaporation, atomic layer deposition, molecular beam epitaxy or chemical vapor deposition; 3. VO2 thin film preparation: A VO2 thin film is prepared on the visible band color control layer by evaporation, magnetron sputtering, pulsed laser deposition, electron beam evaporation, sol-gel method, hydrothermal method, atomic layer deposition or molecular beam epitaxy to obtain a multilayer composite film; 4. VO2 film post-processing: The multilayer composite film is placed in a tubular furnace and kept warm at an argon flow rate of 90 sccm to 120 sccm and a temperature of 400°C to 550°C. Finally, it is naturally cooled to room temperature, thereby completing the preparation method of the UV-shielding color dynamically adjustable VO2 smart window.

7. The method for preparing a UV shielding VO2 smart window with dynamically adjustable color according to claim 6, characterized in that When the step 2 uses radio frequency magnetron sputtering to prepare a Si layer on one side of the pretreated substrate, the specific steps are as follows: vacuuming to 1×10 -3 Pa~2×10 -3 Pa, with Si target as target material, and then under the conditions of RF power of 100W-200W, pressure of 0.4Pa-1.0Pa, argon flow rate of 80sccm-90sccm and substrate temperature of 50℃-200℃, a Si layer is sputtered on one side of the pretreated substrate.

8. The method for preparing a UV shielding color dynamically adjustable VO2 smart window according to claim 6, characterized in that When high-energy pulsed magnetron sputtering is used in step 3 to prepare a VO2 thin film on the visible band color control layer, the steps are as follows: vacuuming to 4×10 -4 Pa~1×10 -3 Pa, taking a metal V target or an element-doped metal V target as a target material, and then preparing a VO2 thin film on a visible band color control layer under the conditions of a frequency of 350 Hz to 400 Hz, a pulse width of 45 μs to 50 μs, a power of 180 W to 200 W, a high-energy pulse voltage of 450 V to 510 V, a pressure of 0.4 Pa to 1.0 Pa, an argon flow rate of 80 sccm to 85 sccm, an oxygen flow rate of 0.8 sccm to 1.4 sccm and a substrate temperature of 200 ° C to 550 ° C, to obtain a multilayer composite thin film.

9. The method for preparing a UV shielding color dynamically adjustable VO2 smart window according to claim 6, characterized in that In step 4, the temperature is raised to 400° C. to 550° C. at an argon gas flow rate of 90 sccm to 120 sccm and a heating rate of 1° C. / min to 5° C. / min.

10. The method for preparing a UV shielding VO2 smart window with dynamically adjustable color according to claim 9, characterized in that In step 4, the temperature is kept at 400° C. to 550° C. for 1 h to 5 h at an argon gas flow rate of 90 sccm to 120 sccm.

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