A near-infrared shielding thermochromic smart window and a preparation method thereof

Abstract

This invention relates to a near-infrared shielded thermochromic smart window and its fabrication method, belonging to the fields of radiative cooling and smart windows. The invention aims to solve the problems of high near-infrared transmittance and low mid- and far-infrared thermal radiation modulation amplitude in existing thermochromic smart windows. The near-infrared shielded thermochromic smart window comprises, from bottom to top, a substrate, a hyperbolic metamaterial structure, a first oxide dielectric layer, and a VO2 metasurface layer. The fabrication method includes: 1. Cleaning the substrate; 2. Fabrication of the hyperbolic metamaterial structure; 3. Fabrication of the first oxide dielectric layer; 4. Fabrication of the VO2 metasurface layer. This invention relates to a near-infrared shielded thermochromic smart window and its fabrication method.

Description

Technical Field

[0001] This invention belongs to the fields of radiative cooling and intelligent windows. Background Technology

[0002] With the continuous development of new energy vehicles, panoramic sunroofs are gradually replacing traditional car sunroof designs. However, the use of panoramic glass can lead to excessively strong light and high temperatures inside the vehicle. Traditional low-emissivity (Low-e) windows have high transparency in visible light and high reflectivity in the mid-to-far infrared range, providing some radiative cooling effect. However, this is mostly static thermal radiation regulation, lacking adaptive temperature control capabilities, and can easily lead to overcooling at low temperatures. In recent years, combining the optical properties of ITO glass and the thermally induced phase transition characteristics of VO2, smart windows such as VO2 / ZnSe / ITO and VO2 / HfO2 / SiO2 / ITO have been fabricated. These windows have high visible transmittance and dynamic adjustment effects in the mid-to-far infrared radiation range. However, the amplitude of mid-to-far infrared thermal radiation regulation is low, and they do not have good near-infrared shielding capabilities. Since solar infrared energy is mainly concentrated in the 800nm~2500nm range, it is even more necessary to suppress the inward transmission of near-infrared energy in hot climates. Summary of the Invention

[0003] This invention aims to address the problems of high near-infrared transmittance and low mid- and far-infrared thermal radiation modulation amplitude in existing thermochromic smart windows, and thus provides a near-infrared shielded thermochromic smart window and its preparation method.

[0004] A near-infrared shielded thermochromic smart window, which consists of a substrate, a hyperbolic metamaterial structure, a first oxide dielectric layer and a VO2 metasurface layer from bottom to top;

[0005] The hyperbolic metamaterial structure is a four-layer structure consisting of alternating second oxide dielectric layers and metal reflective layers arranged from bottom to top;

[0006] The VO2 metasurface layer is composed of multiple W-doped VO2 micro / nano structure units. The W-doped VO2 micro / nano structure units are square in shape, and the side length of the square is 1.5 μm to 4.5 μm. The array of multiple W-doped VO2 micro / nano structure units is disposed on the surface of the first oxide dielectric layer, with a surface coverage of 0.56 to 0.81. The distance between adjacent W-doped VO2 micro / nano structure units is 0.5 μm to 1 μm.

[0007] In the W-doped VO2 micro / nano structure unit, W accounts for 2% of the total number of W and V atoms.

[0008] A method for preparing a near-infrared shielded thermochromic smart window, comprising the following steps:

[0009] I. Cleaning the substrate:

[0010] The substrate is cleaned to obtain the pretreated substrate;

[0011] II. Fabrication of Hyperbolic Metamaterial Structures:

[0012] Using DC magnetron sputtering technology, a four-layer structure was formed by sequentially depositing a second oxide dielectric layer and a metal reflective layer on the pretreated substrate surface to obtain a hyperbolic metamaterial structure.

[0013] III. Preparation of the first oxide dielectric layer:

[0014] The first oxide dielectric layer was deposited on the metal reflective layer at the top of the hyperbolic metamaterial structure using DC magnetron sputtering technology.

[0015] IV. Preparation of VO2 metasurface layer:

[0016] A VO2 layer was deposited on a first oxide dielectric layer using high-energy pulsed magnetron sputtering technology, followed by post-annealing to obtain a planar multilayer film structure. A photoresist layer was coated on the VO2 layer of the planar multilayer film structure and pre-baked. The photoresist was selectively exposed using ultraviolet lithography, followed by post-baking and development. Then, reactive ion beam etching was used for etching, and finally, the photoresist was removed to obtain the VO2 metasurface layer, thus completing the fabrication method of a near-infrared shielded thermochromic smart window.

[0017] The beneficial effects of this invention are:

[0018] This invention utilizes the unique optical properties of hyperbolic metamaterials to achieve low transmittance in the near-infrared band. Simultaneously, by leveraging the high reflectivity of hyperbolic metamaterials in the mid- and far-infrared bands, and combining an infrared high-transmittance dielectric layer with a VO2 phase transition layer, a Fabry-Perot resonant cavity is constructed, achieving significant dynamic tunability in the mid- and far-infrared bands. Finally, by etching VO2 onto the surface to form a metasurface structure, the transmittance in the visible light band is effectively improved. Furthermore, at high temperatures, the localized surface plasmon resonance effect further enhances the high-temperature infrared emissivity, amplifying the change in infrared emissivity.

[0019] The near-infrared shielded thermochromic smart window of this invention has a visible transmittance of 28% to 54%, an average transmittance in the near-infrared band (0.8μm to 2.5μm) as low as 0.2% to 2.0%, and an emissivity variation of 0.41 to 0.54 in the mid- and far-infrared band (2.5μm to 25μm). With a phase transition temperature near room temperature, it has excellent infrared radiation modulation capabilities and is very suitable for smart window applications in the automotive and construction industries.

[0020] This invention relates to a near-infrared shielded thermochromic smart window and its preparation method. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the near-infrared shielded thermochromic smart window of the present invention. 1 is the VO2 metasurface layer, 2 is the first oxide dielectric layer, 3 is the metal reflective layer, 4 is the second oxide dielectric layer, and 5 is the substrate. Detailed Implementation

[0022] Specific implementation method one: Combining Figure 1 This embodiment describes a near-infrared shielded thermochromic smart window, which consists of a substrate, a hyperbolic metamaterial structure, a first oxide dielectric layer, and a VO2 metasurface layer from bottom to top.

[0023] The hyperbolic metamaterial structure is a four-layer structure consisting of alternating second oxide dielectric layers and metal reflective layers arranged from bottom to top;

[0024] The VO2 metasurface layer is composed of multiple W-doped VO2 micro / nano structure units. The W-doped VO2 micro / nano structure units are square in shape, and the side length of the square is 1.5 μm to 4.5 μm. The array of multiple W-doped VO2 micro / nano structure units is disposed on the surface of the first oxide dielectric layer, with a surface coverage of 0.56 to 0.81. The distance between adjacent W-doped VO2 micro / nano structure units is 0.5 μm to 1 μm.

[0025] In the W-doped VO2 micro / nano structure unit, W accounts for 2% of the total number of W and V atoms.

[0026] The film structure described in this embodiment includes a hyperbolic metamaterial layer, an oxide dielectric layer, and a phase change functional layer. The oxide dielectric layer is made of a material that exhibits excellent transmittance in the near-ultraviolet to infrared band.

[0027] This embodiment, based on hyperbolic metamaterials and Fabry-Perot (FP) resonant structures, combines the thermochromic phase transition characteristics of VO2 and the surface plasmon resonance effect to design and fabricate a near-infrared shielded thermochromic smart window. This window effectively suppresses solar energy in the near-infrared band while maintaining visible light transmittance, and also possesses the ability to adaptively adjust mid- and far-infrared radiation. Furthermore, to achieve better performance, the VO2 phase transition temperature is controlled to near room temperature through W doping. This design is expected to demonstrate significant application potential in areas such as panoramic sunroofs for new energy vehicles and building exteriors. The method involved in this invention has universality and practicality.

[0028] The beneficial effects of this embodiment are:

[0029] This embodiment utilizes the unique optical properties of hyperbolic metamaterials to achieve low transmittance in the near-infrared band. Simultaneously, by leveraging the high reflectivity of hyperbolic metamaterials in the mid- and far-infrared bands, and combining an infrared high-transmittance dielectric layer with a VO2 phase transition layer, a Fabry-Perot resonant cavity is constructed, achieving significant dynamic tunability in the mid- and far-infrared bands. Finally, by etching VO2 onto the surface to form a metasurface structure, the transmittance in the visible light band is effectively improved. Furthermore, at high temperatures, the localized surface plasmon resonance effect further enhances the high-temperature infrared emissivity, amplifying the change in infrared emissivity.

[0030] The near-infrared shielded thermochromic smart window described in this embodiment has a visible transmittance of 28% to 54%, an average transmittance in the near-infrared band (0.8μm to 2.5μm) as low as 0.2% to 2.0%, and an emissivity variation of 0.41 to 0.54 in the mid- and far-infrared band (2.5μm to 25μm). With a phase transition temperature near room temperature, it has excellent infrared radiation modulation capabilities and is very suitable for smart window applications in the automotive and construction industries.

[0031] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the substrate is quartz glass. Everything else is the same as in Specific Implementation Method One.

[0032] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the materials of the first oxide dielectric layer and the second oxide dielectric layer are SiO2, ZrO2, HfO2, TiO2, or Al2O3. Everything else is the same as in Specific Implementation Method One or Two.

[0033] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the material of the metal reflective layer is Ag or Au. Everything else is the same as in Specific Implementation Methods One to Three.

[0034] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that: the thickness of the first oxide dielectric layer is 500nm to 1300nm; the thickness of the second oxide dielectric layer is 100nm to 150nm; the thickness of the metal reflective layer is 10nm to 18nm; and the thickness of the VO2 metasurface layer is 20nm to 60nm. Everything else is the same as in Specific Implementation Methods One to Four.

[0035] Specific Implementation Method Six: This implementation method provides a method for preparing a near-infrared shielded thermochromic smart window, which is carried out according to the following steps:

[0036] I. Cleaning the substrate:

[0037] The substrate is cleaned to obtain the pretreated substrate;

[0038] II. Fabrication of Hyperbolic Metamaterial Structures:

[0039] Using DC magnetron sputtering technology, a four-layer structure was formed by sequentially depositing a second oxide dielectric layer and a metal reflective layer on the pretreated substrate surface to obtain a hyperbolic metamaterial structure.

[0040] III. Preparation of the first oxide dielectric layer:

[0041] The first oxide dielectric layer was deposited on the metal reflective layer at the top of the hyperbolic metamaterial structure using DC magnetron sputtering technology.

[0042] IV. Preparation of VO2 metasurface layer:

[0043] A VO2 layer was deposited on a first oxide dielectric layer using high-energy pulsed magnetron sputtering technology, followed by post-annealing to obtain a planar multilayer film structure. A photoresist layer was coated on the VO2 layer of the planar multilayer film structure and pre-baked. The photoresist was selectively exposed using ultraviolet lithography, followed by post-baking and development. Then, reactive ion beam etching was used for etching, and finally, the photoresist was removed to obtain the VO2 metasurface layer, thus completing the fabrication method of a near-infrared shielded thermochromic smart window.

[0044] This embodiment first constructs a hyperbolic metamaterial structure by alternately fabricating oxide thin films and highly reflective metal thin films on a cleaned quartz substrate using DC magnetron sputtering. Next, a thicker oxide thin film is fabricated on the hyperbolic metamaterial structure using DC sputtering to serve as the dielectric layer for the Fabry-Perot resonator. Then, a tungsten (W)-doped vanadium dioxide (VO2) thin film is fabricated using high-energy pulsed magnetron sputtering combined with post-annealing as a phase-change functional layer. Finally, the VO2 metasurface structure is fabricated using ultraviolet lithography and reactive ion etching techniques.

[0045] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method Six in that: in steps two and three, DC magnetron sputtering technology is used to deposit the first oxide dielectric layer or the second oxide dielectric layer at a temperature of 100℃~200℃; in step two, DC magnetron sputtering technology is used to deposit the metal reflective layer at a temperature of 50℃~100℃, a power of 80W~120W, and a deposition gas pressure of 0.6Pa~0.8Pa. Everything else is the same as in Specific Implementation Method Six.

[0046] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Method Six or Seven in that: in step four, high-energy pulsed magnetron sputtering technology is used. Under conditions of a power of 180W to 220W, an argon to oxygen flow ratio of 80 sccm:(0.8 sccm to 1.4 sccm), and a temperature of 300℃ to 400℃, a VO2 layer is deposited on the first oxide dielectric layer using a vanadium-tungsten alloy target. The rest is the same as in Specific Implementation Method Six or Seven.

[0047] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods Six to Eight in that the post-annealing treatment described in step four is specifically carried out at a temperature of 350℃~400℃ and an argon flow rate of 100sccm~120sccm for annealing for 0.5h~3h. Everything else is the same as in Specific Implementation Methods Six to Eight.

[0048] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods Six to Nine in that: in step four, a layer of photoresist is coated onto the VO2 layer of the planar multilayer film structure. Under conditions of 120℃~150℃, a pre-baking process is performed for 2 min~3.5 min. Then, the photoresist is selectively exposed using ultraviolet lithography for 25 s~60 s. Next, under conditions of 100℃~150℃, a post-baking process is performed for 1.5 min~2.5 min, followed by development for 5 s~15 s. Etching is then performed using reactive ion beam etching for 20 s~60 s. Finally, the photoresist is removed. The rest is the same as in Specific Implementation Methods Six to Nine.

[0049] The beneficial effects of the present invention are verified using the following embodiments:

[0050] Example 1:

[0051] A near-infrared shielded thermochromic smart window, which consists of a substrate, a hyperbolic metamaterial structure, a first oxide dielectric layer and a VO2 metasurface layer from bottom to top;

[0052] The hyperbolic metamaterial structure is a four-layer structure consisting of alternating second oxide dielectric layers and metal reflective layers arranged from bottom to top;

[0053] The VO2 metasurface layer is composed of multiple W-doped VO2 micro / nano structure units. The W-doped VO2 micro / nano structure units are square in shape, and the side length of the square is 4 μm. The rectangular array of multiple W-doped VO2 micro / nano structure units is disposed on the surface of the first oxide dielectric layer, with a surface coverage of 0.79 and a distance of 0.5 μm between adjacent W-doped VO2 micro / nano structure units.

[0054] In the W-doped VO2 micro / nano structure unit, W accounts for 2% of the total number of W and V atoms.

[0055] The substrate is quartz glass.

[0056] The material of the first oxide dielectric layer is ZrO2;

[0057] The material of the second oxide dielectric layer is SiO2.

[0058] The metal reflective layer is made of Ag.

[0059] The thickness of the first oxide dielectric layer is 500 nm; the thickness of the second oxide dielectric layer is 110 nm; the thickness of the metal reflective layer is 10 nm; and the thickness of the VO2 metasurface layer is 60 nm.

[0060] The above-mentioned method for preparing a near-infrared shielded thermochromic smart window is carried out according to the following steps:

[0061] I. Cleaning the substrate:

[0062] The substrate was cleaned using analytical grade anhydrous ethanol and ultrapure water as cleaning reagents, and then sealed for later use to obtain the pretreated substrate.

[0063] II. Fabrication of Hyperbolic Metamaterial Structures:

[0064] Using DC magnetron sputtering technology, a four-layer structure was formed by sequentially depositing a second oxide dielectric layer and a metal reflective layer on the pretreated substrate surface to obtain a hyperbolic metamaterial structure.

[0065] The deposition of the second oxide dielectric layer is specifically carried out using DC magnetron sputtering technology at a temperature of 200°C.

[0066] The metal reflective layer was deposited using DC magnetron sputtering technology at a temperature of 50℃, a power of 80W, and a deposition gas pressure of 0.6Pa.

[0067] The hyperbolic metamaterial structure is specifically SiO2(110nm) / Ag(10nm) / SiO2(110nm) / Ag(10nm);

[0068] III. Preparation of the first oxide dielectric layer:

[0069] Using DC magnetron sputtering technology, a first oxide dielectric layer was deposited on the metal reflective layer at the top layer of a hyperbolic metamaterial structure at a temperature of 200℃.

[0070] IV. Preparation of VO2 metasurface layer:

[0071] A VO2 layer was deposited on a first oxide dielectric layer using a vanadium-tungsten alloy target under the conditions of 180W power, argon to oxygen flow rate ratio of 80 sccm:1.4 sccm, and temperature of 300℃. The layer was then annealed for 3 hours at 400℃ and argon flow rate of 100 sccm to obtain a planar multilayer film structure. A photoresist layer was coated onto the VO2 layer of the planar multilayer film structure. The film was pre-baked at 120℃ for 3.5 minutes, selectively exposed to ultraviolet light for 60 seconds, post-baked at 100℃ for 2.5 minutes, developed for 15 seconds, etched using reactive ion beam etching for 60 seconds, and finally the photoresist was removed to obtain the VO2 metasurface layer. This completes the fabrication method of a near-infrared shielded thermochromic smart window.

[0072] The vanadium-tungsten alloy target has a purity of 99.9% and a V:W ratio of 98:2 at%. The photoresist is NRT-250P negative photoresist.

[0073] The visible-near-infrared transmission spectra and mid-far-infrared reflectance spectra of the coating at high temperature (H, 60℃) and low temperature (L, 0℃) were measured using ultraviolet-visible-near-infrared spectroscopy and Fourier transform infrared spectroscopy, respectively. The visible transmittance T at high and low temperatures was obtained by analysis and calculation. lum Average transmittance in the near-infrared band (0.8–2.5 μm) Mid- and far-infrared (2.5 μm–25 μm) emissivity ε and emissivity variation Δε. lum (H) = 34%, T lum (L) = 29%, ε H =0.46, ε L =0.05, Δε =0.41.

[0074] Example 2:

[0075] A near-infrared shielded thermochromic smart window, which consists of a substrate, a hyperbolic metamaterial structure, a first oxide dielectric layer and a VO2 metasurface layer from bottom to top;

[0076] The hyperbolic metamaterial structure is a four-layer structure consisting of alternating second oxide dielectric layers and metal reflective layers arranged from bottom to top;

[0077] The VO2 metasurface layer is composed of multiple W-doped VO2 micro / nano structure units. The W-doped VO2 micro / nano structure units are square in shape, and the side length of the square is 4 μm. The rectangular array of multiple W-doped VO2 micro / nano structure units is disposed on the surface of the first oxide dielectric layer, with a surface coverage of 0.79 and a distance of 0.5 μm between adjacent W-doped VO2 micro / nano structure units.

[0078] In the W-doped VO2 micro / nano structure unit, W accounts for 2% of the total number of W and V atoms.

[0079] The substrate is quartz glass.

[0080] The material of the first oxide dielectric layer is HfO2;

[0081] The material of the second oxide dielectric layer is SiO2.

[0082] The metal reflective layer is made of Ag.

[0083] The thickness of the first oxide dielectric layer is 700 nm; the thickness of the second oxide dielectric layer is 110 nm; the thickness of the metal reflective layer is 12 nm; and the thickness of the VO2 metasurface layer is 50 nm.

[0084] The above-mentioned method for preparing a near-infrared shielded thermochromic smart window is carried out according to the following steps:

[0085] I. Cleaning the substrate:

[0086] The substrate was cleaned using analytical grade anhydrous ethanol and ultrapure water as cleaning reagents, and then sealed for later use to obtain the pretreated substrate.

[0087] II. Fabrication of Hyperbolic Metamaterial Structures:

[0088] Using DC magnetron sputtering technology, a four-layer structure was formed by sequentially depositing a second oxide dielectric layer and a metal reflective layer on the pretreated substrate surface to obtain a hyperbolic metamaterial structure.

[0089] The deposition of the second oxide dielectric layer is specifically carried out using DC magnetron sputtering technology at a temperature of 200°C.

[0090] The metal reflective layer was deposited using DC magnetron sputtering technology at a temperature of 50℃, a power of 80W, and a deposition gas pressure of 0.6Pa.

[0091] The hyperbolic metamaterial structure is specifically SiO2(110nm) / Ag(12nm) / SiO2(110nm) / Ag(12nm);

[0092] III. Preparation of the first oxide dielectric layer:

[0093] Using DC magnetron sputtering technology, a first oxide dielectric layer was deposited on the metal reflective layer at the top layer of a hyperbolic metamaterial structure at a temperature of 100°C.

[0094] IV. Preparation of VO2 metasurface layer:

[0095] A VO2 layer was deposited on a first oxide dielectric layer using a vanadium-tungsten alloy target under the conditions of 200W power, argon to oxygen flow ratio of 80 sccm:1.2 sccm, and temperature of 350℃. The layer was then annealed for 2 hours at 400℃ and argon flow rate of 110 sccm to obtain a planar multilayer film structure. A photoresist layer was coated onto the VO2 layer of the planar multilayer film structure. The film was pre-baked for 3 minutes at 130℃, selectively exposed to ultraviolet light for 50 seconds, post-baked for 2 minutes at 125℃, developed for 10 seconds, etched using reactive ion beam etching for 45 seconds, and finally the photoresist was removed to obtain the VO2 metasurface layer. This completes the fabrication method of a near-infrared shielded thermochromic smart window.

[0096] The vanadium-tungsten alloy target has a purity of 99.9% and a V:W ratio of 98:2 at%. The photoresist is NRT-250P negative photoresist.

[0097] The visible-near-infrared transmission spectra and mid-far-infrared reflectance spectra of the coating at high temperature (H, 60℃) and low temperature (L, 0℃) were measured using ultraviolet-visible-near-infrared spectroscopy and Fourier transform infrared spectroscopy, respectively. The visible transmittance T at high and low temperatures was obtained by analysis and calculation. lum Average transmittance in the near-infrared band (0.8–2.5 μm) Mid- and far-infrared (2.5 μm–25 μm) emissivity ε and emissivity variation Δε. lum (H) = 33%, T lum (L) = 28%, ε H =0.51, ε L =0.05, Δε =0.46.

[0098] Example 3:

[0099] A near-infrared shielded thermochromic smart window, which consists of a substrate, a hyperbolic metamaterial structure, a first oxide dielectric layer and a VO2 metasurface layer from bottom to top;

[0100] The hyperbolic metamaterial structure is a four-layer structure consisting of alternating second oxide dielectric layers and metal reflective layers arranged from bottom to top;

[0101] The VO2 metasurface layer is composed of multiple W-doped VO2 micro / nano structure units. The W-doped VO2 micro / nano structure units are square in shape, and the side length of the square is 3.5 μm. The rectangular array of multiple W-doped VO2 micro / nano structure units is disposed on the surface of the first oxide dielectric layer, with a surface coverage of 0.77 and a distance of 0.5 μm between adjacent W-doped VO2 micro / nano structure units.

[0102] In the W-doped VO2 micro / nano structure unit, W accounts for 2% of the total number of W and V atoms.

[0103] The substrate is quartz glass.

[0104] The material of the first oxide dielectric layer is HfO2;

[0105] The material of the second oxide dielectric layer is SiO2.

[0106] The metal reflective layer is made of Ag.

[0107] The thickness of the first oxide dielectric layer is 700 nm; the thickness of the second oxide dielectric layer is 110 nm; the thickness of the metal reflective layer is 15 nm; and the thickness of the VO2 metasurface layer is 50 nm.

[0108] The above-mentioned method for preparing a near-infrared shielded thermochromic smart window is carried out according to the following steps:

[0109] I. Cleaning the substrate:

[0110] The substrate was cleaned using analytical grade anhydrous ethanol and ultrapure water as cleaning reagents, and then sealed for later use to obtain the pretreated substrate.

[0111] II. Fabrication of Hyperbolic Metamaterial Structures:

[0112] Using DC magnetron sputtering technology, a four-layer structure was formed by sequentially depositing a second oxide dielectric layer and a metal reflective layer on the pretreated substrate surface to obtain a hyperbolic metamaterial structure.

[0113] The deposition of the second oxide dielectric layer is specifically carried out using DC magnetron sputtering technology at a temperature of 200°C.

[0114] The metal reflective layer was deposited using DC magnetron sputtering technology at a temperature of 50℃, a power of 80W, and a deposition gas pressure of 0.6Pa.

[0115] The hyperbolic metamaterial structure is specifically SiO2(110nm) / Ag(15nm) / SiO2(110nm) / Ag(15nm);

[0116] III. Preparation of the first oxide dielectric layer:

[0117] Using DC magnetron sputtering technology, a first oxide dielectric layer was deposited on the metal reflective layer at the top layer of a hyperbolic metamaterial structure at a temperature of 100°C.

[0118] IV. Preparation of VO2 metasurface layer:

[0119] A VO2 layer was deposited on a first oxide dielectric layer using a vanadium-tungsten alloy target under the conditions of high-energy pulsed magnetron sputtering technology at a power of 220W, an argon to oxygen flow rate ratio of 80 sccm:1.0 sccm, and a temperature of 400℃. The layer was then annealed for 1 hour at 400℃ and an argon flow rate of 120 sccm to obtain a planar multilayer film structure. A photoresist layer was coated onto the VO2 layer of the planar multilayer film structure. The film was pre-baked at 140℃ for 2.5 min, selectively exposed to ultraviolet light for 40 s using ultraviolet lithography, post-baked at 150℃ for 1.5 min, developed for 5 s, etched using reactive ion beam etching for 45 s, and finally the photoresist was removed to obtain the VO2 metasurface layer. This completes the fabrication method of a near-infrared shielded thermochromic smart window.

[0120] The vanadium-tungsten alloy target has a purity of 99.9% and a V:W ratio of 98:2 at%. The photoresist is NRT-250P negative photoresist.

[0121] The visible-near-infrared transmission spectra and mid-far-infrared reflectance spectra of the coating at high temperature (H, 60℃) and low temperature (L, 0℃) were measured using ultraviolet-visible-near-infrared spectroscopy and Fourier transform infrared spectroscopy, respectively. The visible transmittance T at high and low temperatures was obtained by analysis and calculation. lum Average transmittance in the near-infrared band (0.8–2.5 μm) Mid- and far-infrared (2.5 μm–25 μm) emissivity ε and emissivity variation Δε. lum (H) = 40%, T lum (L) = 38%, ε H =0.52, ε L =0.10, Δε =0.42.

[0122] Example 4:

[0123] A near-infrared shielded thermochromic smart window, which consists of a substrate, a hyperbolic metamaterial structure, a first oxide dielectric layer and a VO2 metasurface layer from bottom to top;

[0124] The hyperbolic metamaterial structure is a four-layer structure consisting of alternating second oxide dielectric layers and metal reflective layers arranged from bottom to top;

[0125] The VO2 metasurface layer is composed of multiple W-doped VO2 micro / nano structure units. The W-doped VO2 micro / nano structure units are square in shape, and the side length of the square is 1.5 μm. The rectangular array of multiple W-doped VO2 micro / nano structure units is disposed on the surface of the first oxide dielectric layer, with a surface coverage of 0.56 and a distance of 0.5 μm between adjacent W-doped VO2 micro / nano structure units.

[0126] In the W-doped VO2 micro / nano structure unit, W accounts for 2% of the total number of W and V atoms.

[0127] The substrate is quartz glass.

[0128] The material of the first oxide dielectric layer is HfO2;

[0129] The material of the second oxide dielectric layer is ZrO2.

[0130] The metal reflective layer is made of Ag.

[0131] The thickness of the first oxide dielectric layer is 900 nm; the thickness of the second oxide dielectric layer is 120 nm; the thickness of the metal reflective layer is 18 nm; and the thickness of the VO2 metasurface layer is 40 nm.

[0132] The above-mentioned method for preparing a near-infrared shielded thermochromic smart window is carried out according to the following steps:

[0133] I. Cleaning the substrate:

[0134] The substrate was cleaned using analytical grade anhydrous ethanol and ultrapure water as cleaning reagents, and then sealed for later use to obtain the pretreated substrate.

[0135] II. Fabrication of Hyperbolic Metamaterial Structures:

[0136] Using DC magnetron sputtering technology, a four-layer structure was formed by sequentially depositing a second oxide dielectric layer and a metal reflective layer on the pretreated substrate surface to obtain a hyperbolic metamaterial structure.

[0137] The deposition of the second oxide dielectric layer is specifically carried out using DC magnetron sputtering technology at a temperature of 200°C.

[0138] The metal reflective layer was deposited using DC magnetron sputtering technology at a temperature of 50℃, a power of 80W, and a deposition gas pressure of 0.6Pa.

[0139] The hyperbolic metamaterial structure is specifically ZrO2(120nm) / Ag(18nm) / ZrO2(120nm) / Ag(18nm);

[0140] III. Preparation of the first oxide dielectric layer:

[0141] Using DC magnetron sputtering technology, a first oxide dielectric layer was deposited on the metal reflective layer at the top layer of a hyperbolic metamaterial structure at a temperature of 100°C.

[0142] IV. Preparation of VO2 metasurface layer:

[0143] A VO2 layer was deposited on a first oxide dielectric layer using a vanadium-tungsten alloy target at a power of 240W, an argon to oxygen flow rate ratio of 80 sccm:0.8 sccm, and a temperature of 400℃. The layer was then annealed for 0.5 h at 400℃ and an argon flow rate of 120 sccm to obtain a planar multilayer film structure. A photoresist layer was coated onto the VO2 layer of the planar multilayer film structure. The film was pre-baked at 150℃ for 2 min, selectively exposed to ultraviolet light for 30 s using ultraviolet lithography, post-baked at 125℃ for 2 min, developed for 10 s, etched using reactive ion beam etching for 30 s, and finally the photoresist was removed to obtain the VO2 metasurface layer. This completes the fabrication method of a near-infrared shielded thermochromic smart window.

[0144] The vanadium-tungsten alloy target has a purity of 99.9% and a V:W ratio of 98:2 at%. The photoresist is NRT-250P negative photoresist.

[0145] The visible-near-infrared transmission spectra and mid-far-infrared reflectance spectra of the coating at high temperature (H, 60℃) and low temperature (L, 0℃) were measured using ultraviolet-visible-near-infrared spectroscopy and Fourier transform infrared spectroscopy, respectively. The visible transmittance T at high and low temperatures was obtained by analysis and calculation. lum Average transmittance in the near-infrared band (0.8–2.5 μm) Mid- and far-infrared (2.5 μm–25 μm) emissivity ε and emissivity variation Δε. lum (H) = 52%, T lum (L) = 42%, ε H =0.53, ε L =0.10, Δε =0.43.

[0146] Example 5:

[0147] A near-infrared shielded thermochromic smart window, which consists of a substrate, a hyperbolic metamaterial structure, a first oxide dielectric layer and a VO2 metasurface layer from bottom to top;

[0148] The hyperbolic metamaterial structure is a four-layer structure consisting of alternating second oxide dielectric layers and metal reflective layers arranged from bottom to top;

[0149] The VO2 metasurface layer is composed of multiple W-doped VO2 micro / nano structure units. The W-doped VO2 micro / nano structure units are square in shape, and the side length of the square is 2 μm. The rectangular array of multiple W-doped VO2 micro / nano structure units is disposed on the surface of the first oxide dielectric layer, with a surface coverage of 0.64 and a distance of 0.5 μm between adjacent W-doped VO2 micro / nano structure units.

[0150] In the W-doped VO2 micro / nano structure unit, W accounts for 2% of the total number of W and V atoms.

[0151] The substrate is quartz glass.

[0152] The material of the first oxide dielectric layer is HfO2;

[0153] The material of the second oxide dielectric layer is ZrO2.

[0154] The metal reflective layer is made of Ag.

[0155] The thickness of the first oxide dielectric layer is 1100 nm; the thickness of the second oxide dielectric layer is 115 nm; the thickness of the metal reflective layer is 12 nm; and the thickness of the VO2 metasurface layer is 20 nm.

[0156] The above-mentioned method for preparing a near-infrared shielded thermochromic smart window is carried out according to the following steps:

[0157] I. Cleaning the substrate:

[0158] The substrate was cleaned using analytical grade anhydrous ethanol and ultrapure water as cleaning reagents, and then sealed for later use to obtain the pretreated substrate.

[0159] II. Fabrication of Hyperbolic Metamaterial Structures:

[0160] Using DC magnetron sputtering technology, a four-layer structure was formed by sequentially depositing a second oxide dielectric layer and a metal reflective layer on the pretreated substrate surface to obtain a hyperbolic metamaterial structure.

[0161] The deposition of the second oxide dielectric layer is specifically carried out using DC magnetron sputtering technology at a temperature of 200°C.

[0162] The metal reflective layer was deposited using DC magnetron sputtering technology at a temperature of 50℃, a power of 80W, and a deposition gas pressure of 0.6Pa.

[0163] The hyperbolic metamaterial structure is specifically ZrO2(115nm) / Ag(12nm) / ZrO2(115nm) / Ag(12nm);

[0164] III. Preparation of the first oxide dielectric layer:

[0165] Using DC magnetron sputtering technology, a first oxide dielectric layer was deposited on the metal reflective layer at the top layer of a hyperbolic metamaterial structure at a temperature of 100°C.

[0166] IV. Preparation of VO2 metasurface layer:

[0167] A VO2 layer was deposited on a first oxide dielectric layer using a vanadium-tungsten alloy target under the conditions of high-energy pulsed magnetron sputtering technology at a power of 220W, an argon to oxygen flow rate ratio of 80 sccm:1.0 sccm, and a temperature of 400℃. The layer was then annealed for 1 hour at 400℃ and an argon flow rate of 120 sccm to obtain a planar multilayer film structure. A photoresist layer was coated onto the VO2 layer of the planar multilayer film structure. The film was pre-baked for 2 minutes at 150℃, selectively exposed to the photoresist using ultraviolet lithography for 25 seconds, then post-baked for 2 minutes at 125℃, followed by development for 10 seconds, and etching using reactive ion beam etching for 20 seconds. Finally, the photoresist was removed to obtain the VO2 metasurface layer, thus completing the fabrication method of a near-infrared shielded thermochromic smart window.

[0168] The vanadium-tungsten alloy target has a purity of 99.9% and a V:W ratio of 98:2 at%. The photoresist is NRT-250P negative photoresist.

[0169] The visible-near-infrared transmission spectra and mid-far-infrared reflectance spectra of the coating at high temperature (H, 60℃) and low temperature (L, 0℃) were measured using ultraviolet-visible-near-infrared spectroscopy and Fourier transform infrared spectroscopy, respectively. The visible transmittance T at high and low temperatures was obtained by analysis and calculation. lum Average transmittance in the near-infrared band (0.8–2.5 μm) Mid- and far-infrared (2.5 μm–25 μm) emissivity ε and emissivity variation Δε. lum (H) = 49%, T lum (L) = 42%, ε H =0.58, ε L =0.11, Δε =0.47.

[0170] Example 6:

[0171] A near-infrared shielded thermochromic smart window, which consists of a substrate, a hyperbolic metamaterial structure, a first oxide dielectric layer and a VO2 metasurface layer from bottom to top;

[0172] The hyperbolic metamaterial structure is a four-layer structure consisting of alternating second oxide dielectric layers and metal reflective layers arranged from bottom to top;

[0173] The VO2 metasurface layer is composed of multiple W-doped VO2 micro / nano structure units. The W-doped VO2 micro / nano structure units are square in shape, and the side length of the square is 3.5 μm. The rectangular array of multiple W-doped VO2 micro / nano structure units is disposed on the surface of the first oxide dielectric layer, with a surface coverage of 0.60 and a distance of 1 μm between adjacent W-doped VO2 micro / nano structure units.

[0174] In the W-doped VO2 micro / nano structure unit, W accounts for 2% of the total number of W and V atoms.

[0175] The substrate is quartz glass.

[0176] The material of the first oxide dielectric layer is TiO2;

[0177] The material of the second oxide dielectric layer is SiO2.

[0178] The material of the metal reflective layer is Au.

[0179] The thickness of the first oxide dielectric layer is 1100 nm; the thickness of the second oxide dielectric layer is 120 nm; the thickness of the metal reflective layer is 10 nm; and the thickness of the VO2 metasurface layer is 20 nm.

[0180] The above-mentioned method for preparing a near-infrared shielded thermochromic smart window is carried out according to the following steps:

[0181] I. Cleaning the substrate:

[0182] The substrate was cleaned using analytical grade anhydrous ethanol and ultrapure water as cleaning reagents, and then sealed for later use to obtain the pretreated substrate.

[0183] II. Fabrication of Hyperbolic Metamaterial Structures:

[0184] Using DC magnetron sputtering technology, a four-layer structure was formed by sequentially depositing a second oxide dielectric layer and a metal reflective layer on the pretreated substrate surface to obtain a hyperbolic metamaterial structure.

[0185] The deposition of the second oxide dielectric layer is specifically carried out using DC magnetron sputtering technology at a temperature of 200°C.

[0186] The metal reflective layer is deposited using DC magnetron sputtering technology at a temperature of 100℃, a power of 120W, and a deposition gas pressure of 0.8Pa.

[0187] The hyperbolic metamaterial structure is specifically SiO2(120nm) / Au(10nm) / SiO2(120nm) / Au(10nm);

[0188] III. Preparation of the first oxide dielectric layer:

[0189] Using DC magnetron sputtering technology, a first oxide dielectric layer was deposited on the metal reflective layer at the top layer of a hyperbolic metamaterial structure at a temperature of 200℃.

[0190] IV. Preparation of VO2 metasurface layer:

[0191] A VO2 layer was deposited on a first oxide dielectric layer using a vanadium-tungsten alloy target under the conditions of high-energy pulsed magnetron sputtering technology at a power of 220W, an argon to oxygen flow rate ratio of 80 sccm:1.0 sccm, and a temperature of 400℃. The layer was then annealed for 1 hour at 400℃ and an argon flow rate of 120 sccm to obtain a planar multilayer film structure. A photoresist layer was coated onto the VO2 layer of the planar multilayer film structure. The film was pre-baked for 2 minutes at 150℃, selectively exposed to the photoresist using ultraviolet lithography for 25 seconds, then post-baked for 2 minutes at 125℃, followed by development for 10 seconds, and etching using reactive ion beam etching for 20 seconds. Finally, the photoresist was removed to obtain the VO2 metasurface layer, thus completing the fabrication method of a near-infrared shielded thermochromic smart window.

[0192] The vanadium-tungsten alloy target has a purity of 99.9% and a V:W ratio of 98:2 at%. The photoresist is NRT-250P negative photoresist.

[0193] The visible-near-infrared transmission spectra and mid-far-infrared reflectance spectra of the coating at high temperature (H, 60℃) and low temperature (L, 0℃) were measured using ultraviolet-visible-near-infrared spectroscopy and Fourier transform infrared spectroscopy, respectively. The visible transmittance T at high and low temperatures was obtained by analysis and calculation. lum Average transmittance in the near-infrared band (0.8–2.5 μm) Mid- and far-infrared (2.5 μm–25 μm) emissivity ε and emissivity variation Δε. lum (H) = 54%, T lum (L) = 44%, ε H =0.60, ε L =0.12, Δε =0.48.

[0194] Example 7:

[0195] A near-infrared shielded thermochromic smart window, which consists of a substrate, a hyperbolic metamaterial structure, a first oxide dielectric layer and a VO2 metasurface layer from bottom to top;

[0196] The hyperbolic metamaterial structure is a four-layer structure consisting of alternating second oxide dielectric layers and metal reflective layers arranged from bottom to top;

[0197] The VO2 metasurface layer is composed of multiple W-doped VO2 micro / nano structure units. The W-doped VO2 micro / nano structure units are square in shape, and the side length of the square is 4 μm. The rectangular array of multiple W-doped VO2 micro / nano structure units is disposed on the surface of the first oxide dielectric layer, with a surface coverage of 0.79 and a distance of 0.5 μm between adjacent W-doped VO2 micro / nano structure units.

[0198] In the W-doped VO2 micro / nano structure unit, W accounts for 2% of the total number of W and V atoms.

[0199] The substrate is quartz glass.

[0200] The material of the first oxide dielectric layer is Al2O3;

[0201] The material of the second oxide dielectric layer is SiO2.

[0202] The material of the metal reflective layer is Au.

[0203] The thickness of the first oxide dielectric layer is 1200 nm; the thickness of the second oxide dielectric layer is 140 nm; the thickness of the metal reflective layer is 12 nm; and the thickness of the VO2 metasurface layer is 20 nm.

[0204] The above-mentioned method for preparing a near-infrared shielded thermochromic smart window is carried out according to the following steps:

[0205] I. Cleaning the substrate:

[0206] The substrate was cleaned using analytical grade anhydrous ethanol and ultrapure water as cleaning reagents, and then sealed for later use to obtain the pretreated substrate.

[0207] II. Fabrication of Hyperbolic Metamaterial Structures:

[0208] Using DC magnetron sputtering technology, a four-layer structure was formed by sequentially depositing a second oxide dielectric layer and a metal reflective layer on the pretreated substrate surface to obtain a hyperbolic metamaterial structure.

[0209] The deposition of the second oxide dielectric layer is specifically carried out using DC magnetron sputtering technology at a temperature of 200°C.

[0210] The metal reflective layer is deposited using DC magnetron sputtering technology at a temperature of 100℃, a power of 120W, and a deposition gas pressure of 0.8Pa.

[0211] The hyperbolic metamaterial structure is specifically SiO2(140nm) / Au(12nm) / SiO2(140nm) / Au(12nm);

[0212] III. Preparation of the first oxide dielectric layer:

[0213] Using DC magnetron sputtering technology, a first oxide dielectric layer was deposited on the metal reflective layer at the top layer of a hyperbolic metamaterial structure at a temperature of 200℃.

[0214] IV. Preparation of VO2 metasurface layer:

[0215] A VO2 layer was deposited on a first oxide dielectric layer using a vanadium-tungsten alloy target under the conditions of high-energy pulsed magnetron sputtering technology at a power of 220W, an argon to oxygen flow rate ratio of 80 sccm:1.0 sccm, and a temperature of 400℃. The layer was then annealed for 1 hour at 400℃ and an argon flow rate of 120 sccm to obtain a planar multilayer film structure. A photoresist layer was coated onto the VO2 layer of the planar multilayer film structure. The film was pre-baked for 2 minutes at 150℃, selectively exposed to the photoresist using ultraviolet lithography for 25 seconds, then post-baked for 2 minutes at 125℃, followed by development for 10 seconds, and etching using reactive ion beam etching for 20 seconds. Finally, the photoresist was removed to obtain the VO2 metasurface layer, thus completing the fabrication method of a near-infrared shielded thermochromic smart window.

[0216] The vanadium-tungsten alloy target has a purity of 99.9% and a V:W ratio of 98:2 at%. The photoresist is NRT-250P negative photoresist.

[0217] The visible-near-infrared transmission spectra and mid-far-infrared reflectance spectra of the coating at high temperature (H, 60℃) and low temperature (L, 0℃) were measured using ultraviolet-visible-near-infrared spectroscopy and Fourier transform infrared spectroscopy, respectively. The visible transmittance T at high and low temperatures was obtained by analysis and calculation. lum Average transmittance in the near-infrared band (0.8–2.5 μm) Mid- and far-infrared (2.5 μm–25 μm) emissivity ε and emissivity variation Δε. lum (H) = 45%, T lum (L) = 39%, ε H =0.68, ε L =0.14, Δε =0.54.

[0218] Example 8:

[0219] A near-infrared shielded thermochromic smart window, which consists of a substrate, a hyperbolic metamaterial structure, a first oxide dielectric layer and a VO2 metasurface layer from bottom to top;

[0220] The hyperbolic metamaterial structure is a four-layer structure consisting of alternating second oxide dielectric layers and metal reflective layers arranged from bottom to top;

[0221] The VO2 metasurface layer is composed of multiple W-doped VO2 micro / nano structure units. The W-doped VO2 micro / nano structure units are square in shape, and the side length of the square is 4.5 μm. The rectangular array of multiple W-doped VO2 micro / nano structure units is disposed on the surface of the first oxide dielectric layer, with a surface coverage of 0.81 and a distance of 0.5 μm between adjacent W-doped VO2 micro / nano structure units.

[0222] In the W-doped VO2 micro / nano structure unit, W accounts for 2% of the total number of W and V atoms.

[0223] The substrate is quartz glass.

[0224] The material of the first oxide dielectric layer is SiO2;

[0225] The material of the second oxide dielectric layer is TiO2.

[0226] The material of the metal reflective layer is Au.

[0227] The thickness of the first oxide dielectric layer is 1300 nm; the thickness of the second oxide dielectric layer is 150 nm; the thickness of the metal reflective layer is 12 nm; and the thickness of the VO2 metasurface layer is 20 nm.

[0228] The above-mentioned method for preparing a near-infrared shielded thermochromic smart window is carried out according to the following steps:

[0229] I. Cleaning the substrate:

[0230] The substrate was cleaned using analytical grade anhydrous ethanol and ultrapure water as cleaning reagents, and then sealed for later use to obtain the pretreated substrate.

[0231] II. Fabrication of Hyperbolic Metamaterial Structures:

[0232] A hyperbolic metamaterial structure was obtained by sequentially depositing a second oxide dielectric layer and a metal reflective layer on the pretreated substrate surface using DC magnetron sputtering technology to form a four-layer structure.

[0233] The deposition of the second oxide dielectric layer is specifically carried out using DC magnetron sputtering technology at a temperature of 200°C.

[0234] The metal reflective layer is deposited using DC magnetron sputtering technology at a temperature of 100℃, a power of 120W, and a deposition gas pressure of 0.8Pa.

[0235] The hyperbolic metamaterial structure is specifically TiO2(150nm) / Au(12nm) / TiO2(150nm) / Au(12nm);

[0236] III. Preparation of the first oxide dielectric layer:

[0237] Using DC magnetron sputtering technology, a first oxide dielectric layer was deposited on the metal reflective layer at the top layer of a hyperbolic metamaterial structure at a temperature of 200℃.

[0238] IV. Preparation of VO2 metasurface layer:

[0239] A VO2 layer was deposited on a first oxide dielectric layer using a vanadium-tungsten alloy target under the conditions of high-energy pulsed magnetron sputtering technology at a power of 220W, an argon to oxygen flow rate ratio of 80 sccm:1.0 sccm, and a temperature of 400℃. The layer was then annealed for 1 hour at a temperature of 350℃ and an argon flow rate of 120 sccm to obtain a planar multilayer film structure. A photoresist layer was coated onto the VO2 layer of the planar multilayer film structure. The film was pre-baked for 2 minutes at a temperature of 150℃, selectively exposed to the photoresist using ultraviolet lithography for 25 seconds, then post-baked for 2 minutes at a temperature of 125℃, followed by development for 10 seconds, and etching using reactive ion beam etching for 20 seconds. Finally, the photoresist was removed to obtain the VO2 metasurface layer, thus completing the fabrication method of a near-infrared shielded thermochromic smart window.

[0240] The vanadium-tungsten alloy target has a purity of 99.9% and a V:W ratio of 98:2 at%. The photoresist is NRT-250P negative photoresist.

[0241] The visible-near-infrared transmission spectra and mid-far-infrared reflectance spectra of the coating at high temperature (H, 60℃) and low temperature (L, 0℃) were measured using ultraviolet-visible-near-infrared spectroscopy and Fourier transform infrared spectroscopy, respectively. The visible transmittance T at high and low temperatures was obtained by analysis and calculation. lum Average transmittance in the near-infrared band (0.8–2.5 μm) Mid- and far-infrared (2.5 μm–25 μm) emissivity ε and emissivity variation Δε. lum (H) = 46%, T lum (L) = 40%, ε H =0.73, ε L =0.23, Δε =0.50.

Claims

1. A near-infrared-shielded thermochromic smart window, characterized in that It consists of a substrate, a hyperbolic metamaterial structure, a first oxide dielectric layer, and a VO2 metasurface layer from bottom to top. The hyperbolic metamaterial structure is a four-layer structure consisting of alternating second oxide dielectric layers and metal reflective layers arranged from bottom to top; The VO2 metasurface layer is composed of multiple W-doped VO2 micro / nano structure units. The W-doped VO2 micro / nano structure units are square in shape, and the side length of the square is 1.5 μm to 4.5 μm. The array of multiple W-doped VO2 micro / nano structure units is disposed on the surface of the first oxide dielectric layer, with a surface coverage of 0.56 to 0.

81. The distance between adjacent W-doped VO2 micro / nano structure units is 0.5 μm to 1 μm. In the W-doped VO2 micro / nano structure unit, W accounts for 2% of the total number of W and V atoms; The materials of the first oxide dielectric layer and the second oxide dielectric layer are SiO2, ZrO2, HfO2, TiO2 or Al2O3; The metal reflective layer is made of Ag or Au.

2. A near-infrared shielding thermochromic smart window according to claim 1, characterized in that The substrate is quartz glass.

3. A near-infrared shielding thermochromic smart window according to claim 1, characterized in that The thickness of the first oxide dielectric layer is 500nm~1300nm; the thickness of the second oxide dielectric layer is 100nm~150nm; the thickness of the metal reflective layer is 10nm~18nm; and the thickness of the VO2 metasurface layer is 20nm~60nm.

4. The method for preparing a near-infrared shielded thermochromic smart window as described in claim 1, characterized in that... It is done in the following steps: I. Cleaning the substrate: The substrate is cleaned to obtain the pretreated substrate; II. Fabrication of Hyperbolic Metamaterial Structures: Using DC magnetron sputtering technology, a four-layer structure was formed by sequentially depositing a second oxide dielectric layer and a metal reflective layer on the pretreated substrate surface to obtain a hyperbolic metamaterial structure. III. Preparation of the first oxide dielectric layer: The first oxide dielectric layer was deposited on the metal reflective layer at the top of the hyperbolic metamaterial structure using DC magnetron sputtering technology. IV. Preparation of VO2 metasurface layer: A VO2 layer was deposited on a first oxide dielectric layer using high-energy pulsed magnetron sputtering technology, followed by post-annealing to obtain a planar multilayer film structure. A photoresist layer was coated on the VO2 layer of the planar multilayer film structure and pre-baked. The photoresist was selectively exposed using ultraviolet lithography, followed by post-baking and development. Then, reactive ion beam etching was used for etching, and finally, the photoresist was removed to obtain the VO2 metasurface layer, thus completing the fabrication method of a near-infrared shielded thermochromic smart window.

5. A method of making a near-infrared shielding, thermochromic smart window according to claim 4, characterized in that In steps two and three, DC magnetron sputtering technology is used to deposit the first oxide dielectric layer or the second oxide dielectric layer at a temperature of 100℃~200℃. In step two, DC magnetron sputtering technology is used to deposit the metal reflective layer at a temperature of 50℃~100℃, a power of 80W~120W, and a deposition gas pressure of 0.6Pa~0.8Pa.

6. The method of claim 4, wherein the near-infrared shielding thermochromic smart window is prepared by the steps of In step four, high-energy pulsed magnetron sputtering technology is used to deposit a VO2 layer on the first oxide medium layer under the conditions of power of 180W~220W, argon to oxygen flow ratio of 80sccm:(0.8sccm~1.4sccm) and temperature of 300℃~400℃.

7. The method for preparing a near-infrared shielded thermochromic smart window according to claim 4, characterized in that... The post-annealing treatment described in step four is specifically carried out at a temperature of 350℃~400℃ and an argon flow rate of 100sccm~120sccm for 0.5h~3h.

8. The method for preparing a near-infrared shielded thermochromic smart window according to claim 4, characterized in that... Step 4: Coat a layer of photoresist on the VO2 layer of the planar multilayer film structure. Under the condition of 120℃~150℃, pre-baking for 2min~3.5min, selectively expose the photoresist for 25s~60s using ultraviolet lithography, then post-baking for 1.5min~2.5min under the condition of 100℃~150℃, followed by development for 5s~15s, etching for 20s~60s using reactive ion beam etching, and finally remove the photoresist.

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