A High-Effective Method to Prepare VO2(M) Nanopowders and Thin Films with Excellent Thermochromic Properties

Abstract

Highly purified VO2(M) nanopowders was prepared by sol-gel process combined with mild hydrothermal reaction. The results illustrated the VO2(M) nanopowders are uniform quasi-sperical single crystal with a particle size of similar to 25 nm. The DSC analysis proves that nanopowders show superior phase transition properties around 68 degrees C. A kind of clear VO2(M) slurry was prepared by adding appropriate dispersing agent, as well as ultrasonic dispersion and high speed stirring dispersion methods. The final VO2(M) thin film prepared by spin-coating process has higher visible transmission (67.7%), higher luminous transmittance (61.5%) and higher solar modulation ability (12.5%), as well as lower haze (5.8%). The nanopowders synthesis method and film forming technology are extremely important in promoting the VO2(M) thermochromic films material development and making it closing to practical application as smart windows coatings.