(a), Three-dimensional structure of the prepared VO2-based smart window. The solar cells are assembled in a manner that surrounds the module. Here, 3 sides are shown. (b), c and d are the cross-sectional views of a with different DP. (b), A VO2 film on quartz that served as a scattering medium. The scattering medium in c is a composite created by the dispersion of VO2@SiO2@TiO2 core-shell-shell particles in PU. This composite is cast in PDMS. The scattering medium in d is a smooth VO2 thin film. SC, LGL and DP refer to the solar cell, light guider layer and low reflective index medium, respectively. (b, c and d) show the principle scheme of the devices Ca, Cb (Figure 3e) and Cc (Figure 3f), respectively. When light interacts with the VO2 particle, partial light was scattered and reflected to the solar cell to generate electricity. Cl is a 1.5-V lamp, which was employed to demonstrate whether the smart window works for generation. The two devices in series in Figure 3e could light a 1.5 V lamp.