Effects of TiO_2 Interlayers on the Optical Switching of VO_2 Thin Films Grown by Sol-Gel Process

Thermochromic VO 2 and V x W 1-x O 2 films were deposited on TiO 2 /mica substrates.The TiO 2 /mica substrates were fabricated via Sol-Gel process,and the hydrophilicity of the TiO 2 /mica substrate was improved under UV light irradiated.The V 2 O 5 sol was deposited on the TiO 2 /mica substrate by the spin coating method,and then it was annealed.SEM and XRD analysis were applied to analyze the morphology,phases and microstructure of the films.FTIR was used to study the thermochromic properties.The results suggest that VO 2 /TiO 2 grow preferentially along single orientation.V x W 1-x O 2 /TiO 2 composite film is impossible to fabricate single orientation films.TiO 2 interlayers are favorable to compact the VO 2 thin films and reduce the transition temperature.It will make the hysteresis width of V x W 1-x O 2 /TiO 2 composite film reduce to about 4℃ particularly.