Thermochromic vanadium dioxide film on textured silica substrate for smart window with enhanced visible transmittance and tunable infrared radiation

Thermochromic material vanadium dioxide (VO2) has been extensively studied as a smart window material, which could change its optical properties with temperature due to its phase transition. A large percentage of the visible and thermal infrared light are expected to transmit in its cold dielectric state, while VO2 can regulate infrared transmittance in its hot metallic state. In this study, we proposed a periodic hexagonal array of VO2-based disks to achieve improvement of visible transmittance and maintain the outstanding solar-heat modulation ability. The VO2 thin film (50 nm) on our proposed textured substrate showed ~5% higher transmittance in the visible region at 555 nm than the planar VO2 thin film. This work provides an insight into the structural design of VO2-based smart window with enhanced visible light transmittance and effective infrared shielding at high temperatures.