Preparation And Optical Performance Of Vanadium Dioxide By Sol-Gel Method

Vanadium dioxide film was prepared by sol-gel with vanadium pentoxide powder and phase transformation performance was studied by transmitted spectrum with variable temperature in this paper. In addition, we had deposited SiO2two dimensional photonic crystals on the surface of VO2film resulting changeable color as well as enhanced transmitted spectrum.Firstly, we had prepared V2O5sol by pouring fused V2O5into water, and added PVP(K30) into sol to react with V2O5particles by hydrogen bond in order to improve the stability of sol. The wettability of sol to substrate and manufacturability of V2O5sol film had been enhanced, too. Then we got a uniform surface V2O5film by dip-coating method. The TG-DTA of V2O5gel after dried in the air was used and analyzed the transformation with temperature increasing. Then we got the parameters of thermal treatment from the TG-DTA result.Secondly, we took thermal treatment of V2O5gel film on the glass substrate with different thermal treatment methods according to the TG-DTA. It had been confirmed PVP played a great role between transformation from V2O5to VO2, while Na ion diffusion from the substrate prevented the formation of VO2.Thirdly, we took a orthogonal experiment of the V2O5gel film on the fused silica considering variable parameters. Taking advantage of XPS and Raman spectrum, we confirmed S6film was purely VO2film with perfect phase transformation performance. We measured the optical performance of VO2film by transmitted spectrum with variable temperature. It has been confirmed the morphology of VO2film had a strong effect on the transmittance by reducing the refractive index of the film. Comparatively, the thickness of the film had an oppositely effect between the transmittance in visible wavelength and thermal control ability. It could reduce the transmittance in visible wavelength while improve the thermal control ability with thickness increasing. Besides, the film obtained by dip-coating method had a better optical performance with its novel two layer structure which dispersed on the two sides of substrate.Finally, we deposited SiO2two dimensional photonic crystals on the film of VO2. The color of VO2film was improved because of the VO2/SiO2microstructure. Moreover, the transmittance of VO2film in visible wavelength has been improved according to the microstructure.