Fig. 1. Principle of VO₂ thermochromic smart window. (a) Schematic diagram of the working principle; (b) spectral performance of ideal smart window in heating mode; (c) spectral performance of ideal smart window in cooling mode

Fig. 2. Design method and principle for improving the performance of VO₂-based smart window

Fig. 3. Performance of VO₂ smart windows reported in recent years

Fig. 4. Designsss of multifunctional anti-reflection film. (a) Mechanism and principle of adjustable ARC^[27]; (b) schematic diagram and spectral properties of movable H₂O anti-reflection film^[28]; (c) flowchart of preparation and spectral properties of VO₂/V₂O₅/V₃O₇ composite anti-reflection film^[29]; (d) optical photograph, structural schematic, and spectral properties of the TiO₂(A)/VO₂(M)/TiO₂(R) multilayer film^[30]; (e) schematic diagram and spectral properties of the SiO₂/TiO₂(α)/VO₂/TiO₂(A) multilayer structure^[31]

Fig. 5. Designs of nanoparticle composite film. (a) Preparation process, microstructure and spectral properties of VO₂/Si-Al gel nanocomposite film^[33]; (b) preparation process, working principle and spectral properties of VO₂/SiO₂ aerogel composite film^[34]; (c) spectral properties and infrared imaging of VO₂/ATO nanocomposite film^[36]

Fig. 6. Porous design. (a) Preparation process and spectral properties of 3D ordered porous VO₂ films^[37]; (b) porous structure diagram and spectral properties of VO₂ prepared by self-template method^[39]; (c) schematic diagram and spectral properties of VO₂ with island surface microstructure^[41]; (d) schematic diagram of VO₂ ordered honeycomb surface microstructure and spectral properties^[44]; (e) preparation process and spectral properties of Karst landform-like VO₂ films^[40]

Fig. 7. Structural design of infrared low emissivity. (a) Schematic diagram of Low-E/VO₂ double-layer structure heat preservation mechanism; (b) spectral properties of Pt/VO₂ bilayer structure^[52]; (c) spectral properties of VO₂, AZO and VO₂/AZO bilayer structure^[54]; (d) spectral properties and infrared imaging of VO₂/ITO double-layer structure^[55]

Fig. 8. Dynamic control designs of infrared band emissivity. (a) Schematic structure and spectral properties of VO₂/PMMA/Low-E/Glass/Low-E^[57]; (b) preparation process and crystal structure characterization of porous VO₂/ZnSe thin film^[58]; (c) working principle and spectral properties of VO₂ super-surface structure^[59]