A VO2 smart window with dynamically adjustable ultraviolet shielding color and its preparation method

Abstract

The application discloses a VO2 smart window with dynamic color adjustment and ultraviolet shielding function and a preparation method thereof, and relates to a smart window with dynamic color adjustment and a preparation method thereof. The application aims at solving the problem that the existing smart window cannot simultaneously have the functions of ultraviolet shielding and dynamic color adjustment. The VO2 smart window is composed of a transparent substrate, a visible waveband color regulation layer and a VO2 functional layer from bottom to top. The preparation method comprises the following steps: firstly, cleaning the substrate; secondly, preparing the visible waveband color regulation layer; thirdly, preparing the VO2 thin film; and fourthly, post-treating the VO2 thin film. The application is used for the VO2 smart window with dynamic color adjustment and ultraviolet shielding function and the preparation 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 primary means of heat exchange between buildings and the external environment, accounting for up to 50% of the total energy used in heat exchange. Smart windows can dynamically adjust the transmittance, reflectivity, and absorptivity of sunlight in response to external environmental stimuli or human control, effectively reducing a building's energy consumption. Furthermore, long-term exposure to high levels of UV radiation can significantly harm human health. The main hazards of UV radiation include skin damage, increased risk of skin cancer, and eye damage. UV radiation can also cause fading and aging of indoor furniture and flooring. Therefore, smart windows with UV shielding capabilities 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 properties. During the phase transition from the low-temperature monoclinic phase to the high-temperature rutile phase, its optical and electrical properties undergo abrupt changes. Specifically, VO2 thin films exhibit high transmittance in the infrared at low temperatures and high reflectivity at high temperatures, making them ideal for smart window applications. However, due to strong intra- and inter-band absorption in the short-wavelength range between VO2's metallic and semiconducting states, VO2 thin films exhibit a brownish-yellow color, making them less user-friendly for smart windows.

[0004] Therefore, realizing a VO2 smart window with both UV shielding function and dynamic color adjustment 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 existing smart windows cannot simultaneously have 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 consists of a transparent substrate, a visible band color regulation layer, and a VO2 functional layer from bottom to top;

[0007] The thickness of the VO2 functional layer is 20nm to 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 pretreated substrate;

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

[0012] A visible wavelength 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] VO2 thin films are 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 multilayer composite films;

[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 transmittance peak of Si thin film in the visible band will redshift as the thickness increases, so Si thin 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. The present invention is based on the phase change material VO2, and utilizes the characteristic of sudden change in optical properties before and after the phase change. In combination with Si with certain absorption in the ultraviolet and visible bands, a VO2-based thermochromic smart window with adjustable color that blocks ultraviolet rays is prepared. Changing the thickness of Si can achieve static adjustment of the color of the smart window. At the same time, the color of the smart window can be dynamically controlled with temperature changes as the VO2 phase changes. 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 dynamically controlled.

[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 architectural beautification and energy saving.

[0021] (3) The preparation process has the characteristics of diversity, simple method, low cost, high repeatability, and large-area preparation. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 Figure 1 is a structural schematic diagram of the VO2 smart window with dynamic adjustable ultraviolet shielding color according to the present application, 1 is a transparent substrate, 2 is a visible waveband color regulation layer, and 3 is a VO2 functional layer;

[0023] Figure 2 Figure 1 is a structural schematic diagram of the VO2 smart window with dynamic adjustable ultraviolet shielding color according to the present application, 1 is a transparent substrate, 2 is a visible waveband color regulation layer, and 3 is a VO2 functional layer;

[0024] Figure 3 Figure 1 is a structural schematic diagram of the VO2 smart window with dynamic adjustable ultraviolet shielding color according to the present application, 1 is a transparent substrate, 2 is a visible waveband color regulation layer, and 3 is a VO2 functional layer. DETAILED DESCRIPTION

[0025] DETAILED DESCRIPTION Figure 1 In this embodiment, the VO2 smart window with dynamic adjustable ultraviolet shielding color is composed of a transparent substrate, a visible waveband color regulation layer, and a VO2 functional layer from bottom to top.

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

[0027] In this embodiment, a geometric model is constructed according to the complex refractive index of the transparent substrate, the color regulation layer, and the VO2 layer. The spectral transmittance is simulated based on the constructed geometric model. The spectral transmittance is converted into the optical properties of the smart window based on the standard luminous efficiency function of vision and the solar radiation spectrum. The thickness and preparation parameters of the required color regulation layer and VO2 layer are determined by evaluating the optical properties of the smart window.

[0028] The beneficial effects of this embodiment are:

[0029] The peak transmittance of Si thin film in the visible band will redshift as the thickness increases, so Si thin 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 its sudden change in optical properties before and after the phase change. In combination with Si with certain absorption in the ultraviolet and visible bands, a color-adjustable thermochromic smart window based on VO2 that blocks ultraviolet rays is prepared. Changing the thickness of Si can achieve static adjustment of the color of the smart window. At the same time, the color of the smart window can be dynamically controlled with temperature changes as the VO2 phase changes. 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 dynamically controlled.

[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 adjustment 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 architectural beautification and energy saving.

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

[0033] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that the transparent substrate has a transmittance of 55% or greater in the solar wavelength range and is made of quartz glass, soda-lime glass, CaF2, sapphire, polydimethylsiloxane, or polymethyl methacrylate. Other aspects are the same as specific embodiment 1.

[0034] Specific embodiment 3: This embodiment differs from either specific embodiment 1 or 2 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. Other aspects are the same as specific embodiments 1 or 2.

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

[0036] Specific embodiment 5: This embodiment differs from specific embodiments 1 to 4 in that the thickness of the visible wavelength color control layer is 10 nm to 300 nm.

[0037] Specific embodiment 6: This embodiment 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 pretreated substrate;

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

[0041] A visible wavelength 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] VO2 thin films are 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 multilayer composite films;

[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 differs 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, the specific steps are as follows: vacuuming to 1×10 -3 Pa~2×10 -3 Pa, using a Si target as the target material, and then sputtering on one side of the pretreated substrate to obtain a Si layer under the conditions of a radio frequency power of 100 W to 200 W, a pressure of 0.4 Pa to 1.0 Pa, an argon gas flow rate of 80 sccm to 90 sccm, and a substrate temperature of 50° C. to 200° C. The rest is the same as in the sixth embodiment.

[0047] Specific embodiment eight: This embodiment differs from either specific embodiment six or seven in that: when high-energy pulsed magnetron sputtering is used in step three 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, then preparing a VO2 thin film on the visible wavelength 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 obtain a multilayer composite thin film. Other aspects are the same as those of the sixth or seventh specific embodiment.

[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. Other steps are 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 argon flow rate is 90 sccm to 120 sccm and the temperature is 400° C. to 550° C. and the temperature is maintained for 1 to 5 hours. Other steps are the same as specific embodiments 6 to 9.

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

[0051] Example 1:

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

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

[0054] The transparent substrate is quartz glass.

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

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

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

[0058] I. Substrate cleaning:

[0059] Polishing and cleaning the transparent substrate to obtain a pretreated substrate;

[0060] II. Preparation of visible band color modulation layer:

[0061] Using radio frequency magnetron sputtering, first vacuum to 1x10 -3 Pa, and then using Si target as target material, under the conditions of radio frequency power of 150 W, pressure of 0.4 Pa, argon flow rate of 80 sccm and substrate temperature of 200℃, sputtering on one side of the pretreated substrate to obtain a visible band color modulation layer, i.e. a Si layer;

[0062] III. VO2 thin film preparation:

[0063] Using high-energy pulse magnetron sputtering, first vacuum to 4x10 -4 Pa, and then using a metal V target as a target material, under the conditions of frequency of 400 Hz, pulse width of 50μs, power of 180 W, high-energy pulse voltage of 510 V, pressure of 0.85 Pa, argon flow rate of 80 sccm, oxygen flow rate of 0.8 sccm and substrate temperature of 200℃, a VO2 thin film is prepared on the visible band color modulation layer to obtain a multilayer structure composite thin film;

[0064] IV. VO2 thin film post-processing:

[0065] The multilayer structure composite thin film is placed in a tube furnace, under the conditions of argon flow rate of 100 sccm and heating rate of 1℃ / min, heated to 400℃, under the conditions of argon flow rate of 100 sccm and temperature of 400℃, heat preservation for 5h, and finally natural cooling to room temperature, i.e. the preparation method of the UV shielding color dynamically adjustable VO2 smart window based on the UV shielding color dynamically adjustable VO2 smart window is completed.

[0066] The UV shielding color dynamically adjustable VO2 smart window prepared in Example 1 is subjected to spectral transmittance in the wavelength range of 200nm-2500nm at temperatures of 30℃ and 90℃, and the UV band (200nm-380nm) transmittance is calculated to be <9%, the visible light band (380nm-780nm) transmittance is 40.62%, and the solar band (280nm-2500nm) heat regulation ability is 2.33%. When the temperature is lower than the phase transition temperature, the color coordinates are (0.41642, 0.43096), and when the temperature is higher than the phase transition temperature, the color coordinates are (0.36419, 0.39675).

[0067] Example 2: The difference between this example and Example 1 is that the thickness of the visible band color modulation layer is 20nm. The others are the same as Example 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 was calculated, and the transmittance in the ultraviolet band (200nm to 380nm) was <7%, the transmittance in the visible light band (380nm to 780nm) was 43.95%, and the thermal regulation ability in the sunlight band (280nm to 2500nm) was 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] Example 3: This example differs from Example 1 in that the thickness of the visible band color control layer is 30 nm. Other aspects are the same as Example 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 was calculated, and the transmittance in the ultraviolet band (200nm to 380nm) was <7%, the transmittance in the visible light band (380nm to 780nm) was 43.34%, and the thermal regulation ability in the sunlight band (280nm to 2500nm) was 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] Example 4: This example differs from Example 1 in that the thickness of the visible band color control layer is 40 nm. Other aspects are the same as Example 1.

[0072] The spectral transmittance of the ultraviolet shielding VO2 smart window with dynamically adjustable color prepared in Example 4 was measured 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 5%, the transmittance in the visible light band (380nm to 780nm) was 39.81%, and the thermal regulation ability in the sunlight band (280nm to 2500nm) was 5.11%. When the temperature was lower than its phase transition temperature, the color coordinates were (0.18546, 0.21528), and when the temperature was higher than its phase transition temperature, the color coordinates were (0.34848, 0.18484).

[0073] Example 5: This example differs from Example 1 in that the thickness of the visible band color control layer is 50 nm. Other aspects are the same as Example 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 was calculated, and the transmittance in the ultraviolet band (200nm to 380nm) was <3%, the transmittance in the visible light band (380nm to 780nm) was 36.51%, and the thermal regulation ability in the sunlight band (280nm to 2500nm) was 6.12%. When the temperature was lower than its phase transition temperature, the color coordinates were (0.22826, 0.34893), and when the temperature was higher than its phase transition temperature, the color coordinates were (0.2253, 0.20586).

[0075] Example 6: This example differs from Example 1 in that the thickness of the visible band color control layer is 60 nm. Other aspects are the same as Example 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 was calculated, and the transmittance in the ultraviolet band (200nm to 380nm) was <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] Example 7: This example differs from Example 1 in that the thickness of the visible band color control layer is 70 nm. Other aspects are the same as Example 1.

[0078] The spectral transmittance of the ultraviolet shielding VO2 smart window with dynamically adjustable color prepared in Example 7 was measured 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%, and the thermal regulation ability in the sunlight band (280nm to 2500nm) was 7.65%. 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] Example 8: This example differs from Example 1 in that the thickness of the visible band color control layer is 80 nm. Other aspects are the same as Example 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 calculated, and the transmittance in the ultraviolet band (200nm to 380nm) was <1.5%, the transmittance in the visible light band (380nm to 780nm) was 37.83%, and the thermal regulation ability in the sunlight band (280nm to 2500nm) was 7.81%. When the temperature is lower than its phase transition temperature, the color coordinates are (0.36329, 0.29999), and when it is higher than its phase transition temperature, the color coordinates are (0.42133, 0.47307).

[0081] Example 9: This example differs from Example 1 in that the thickness of the visible wavelength color control layer is 90 nm. Other aspects are the same as Example 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 was calculated, and the transmittance in the ultraviolet band (200nm to 380nm) was <1%, the transmittance in the visible light band (380nm to 780nm) was 39.21%, and the thermal regulation ability in the sunlight band (280nm to 2500nm) was 7.74%. 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] Example 10: This example differs from Example 1 in that the thickness of the visible wavelength color control layer is 100 nm. Other aspects are the same as Example 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 was calculated, and the transmittance in the ultraviolet band (200nm to 380nm) was <0.6%, the transmittance in the visible light band (380nm to 780nm) was 38.91%, and the thermal regulation ability in the sunlight band (280nm to 2500nm) was 7.60%. When the temperature is lower than its phase transition temperature, the color coordinates are (0.31328, 0.26065), and when it is higher than its phase transition temperature, the color coordinates are (0.43162, 0.28853).

[0085] Comparative Experiment: This comparative experiment differs from Example 1 in that the thickness of the visible band color control layer is 0 nm. Other aspects are the same as Example 1.

[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 the calculated 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 VO2 smart window with dynamically adjustable color prepared in Examples 1 to 10 and the comparative experiment; in the figure, SiO2 / Si / VO2(M) represents VO2 before phase transition, SiO2 / Si / VO2(R) represents it after phase transition, and 0mm to 100nm in the figure represents the thickness change of the color control layer Si in the visible band. As can be seen from the figure, the smart window has a high visible transmittance, and the transmission spectra of the smart window before and after the vanadium oxide phase transition are significantly different, and it has considerable thermal control capabilities. As the thickness of the color control layer increases, the transmission peak of the smart window in the visible band gradually redshifts, indicating that changing the thickness of the color control layer can achieve static control of the color of the UV-shielding VO2 smart window with dynamically adjustable color.

[0088] Figure 3 The reflective chromaticity diagram of the UV shielding color dynamically adjustable VO2 smart window prepared in Examples 1 to 10 and the comparative experiment; in the figure, M in M-0nm to M-100nm represents the phase before change, R in R-0nm to R-100nm represents the phase after change, and 0nm to 100nm represents the thickness of the color control layer in the visible band. As can be seen from the figure, regulating the thickness of the color control layer can achieve static color control across the color gamut of the smart window, which is consistent with the Figure 2 The predicted results are consistent. Comparing the chromaticity diagrams of VO2 before and after the phase transition for the same color-control layer thickness reveals that the color of the VO2 smart window with dynamically adjustable UV shielding color achieves significant color changes before and after the phase transition, even changing between cool and warm 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 UV shielding color, characterized by It consists of a transparent substrate, a visible band color control 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 element-doped VO2; 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 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 visible band color regulating layer is Si; The thickness of the visible band color control layer is 10nm~300nm; The transmittance peak of the Si film in the visible band will red-shift as the thickness increases, causing the smart window to exhibit different colors before and after the VO2 phase transition.

2. The method for preparing a VO2 smart window with dynamically adjustable ultraviolet shielding color according to 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 pretreated substrate; 2. Preparation of visible band color control layer: A visible wavelength 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: VO2 thin films are 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 multilayer composite films; 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~120 sccm and a temperature of 400°C~550°C. Finally, it is naturally cooled to room temperature, completing the preparation method of the UV-shielding color dynamically adjustable VO2 smart window.

3. The method for preparing a UV shielding VO2 smart window with dynamically adjustable color according to claim 2, characterized in that When the Si layer is prepared on one side of the pre-treated substrate by radio frequency magnetron sputtering in step 2, the following steps are specifically performed: vacuuming to 1×10 -3 Pa~2×10 -3 Pa, with Si target as target material, and then sputtering a Si layer on one side of the pretreated substrate 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℃.

4. The method for preparing a UV shielding VO2 smart window with dynamically adjustable color according to claim 2, 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, using a metal V target or an element-doped metal V target as the target material, and then preparing a VO2 thin film on a visible band color control layer under the conditions of a frequency of 350Hz~400Hz, a pulse width of 45μs~50μs, a power of 180W~200W, a high-energy pulse voltage of 450V~510V, a pressure of 0.4Pa~1.0Pa, an argon flow rate of 80sccm~85sccm, an oxygen flow rate of 0.8sccm~1.4sccm and a substrate temperature of 200℃~550℃, thereby obtaining a multilayer composite film.

5. The method for preparing a UV shielding VO2 smart window with dynamically adjustable color according to claim 2, characterized 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.

6. The method for preparing a UV shielding VO2 smart window with dynamically adjustable color according to claim 5, characterized in that In step 4, the argon gas flow rate is 90 sccm-120 sccm and the temperature is 400° C.-550° C., and the temperature is maintained for 1 hour-5 hours.

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