Design of Antireflection and Enhanced Thermochromic Properties of TiO2/VO2 Thin Films

VO2-based thin films exhibit great potential applications in thermochromic smart windows. However, it is still a challenge to synergistically achieve the high luminous transmittance (T-lum) and large solar modulation (Delta T-sol). In this paper, antireflective (AR) TiO2/VO2 thin films are designed through optical simulations, and the thin films with optimized film thickness are prepared by magnetron sputtering. The overall performances of the thin films are significantly improved. Compared with single-layer VO2, the T-lum value of the TiO2/VO2 thin film is significantly increased from 29.03% to 46.29% by 59.5%, and the Delta T-sol value is increased up to 16.03%. The T-lum and Delta T-sol values of the TiO2/VO2/TiO2 sandwiched thin films can be further improved up to 50.49% and 20.11%, respectively, owing to the light interference at the interfaces between the multilayers. The results provide an effective strategy for improving the performance of smart windows.