Anisotropic vanadium dioxide sculptured thin films with superior thermochromic properties

VO(2) (M) STF through reduction of V(2)O(5) STF was prepared. The results illustrate that V(2)O(5) STF can be successfully obtained by oblique angle thermal evaporation technique. After annealing at 550°C/3 min, the V(2)O(5) STF deposited at 85° can be easily transformed into VO(2) STF with slanted columnar structure and superior thermochromic properties. After deposition SiO(2) antireflective layer, T(lum) of VO(2) STF is enhanced 26% and ΔT(sol) increases 60% compared with that of normal VO(2) thin films. Due to the anisotropic microstructure of VO(2) STF, angular selectivity transmission of VO(2) STF is observed and the solar modulation ability is further improved from 7.2% to 8.7% when light is along columnar direction. Moreover, the phase transition temperature of VO(2) STF can be depressed into 54.5°C without doping. Considering the oblique incidence of sunlight on windows, VO(2) STF is more beneficial for practical application as smart windows compared with normal homogenous VO(2) thin films.