VO2 thermochromic smart windows: From nanoparticles to flexible foils

Abstract

VO2 (M1, R) demonstrates a temperature-controlled irreversible phase-transition character, which is named Mott phase transition and occurs at 68℃ for bulk VO2 (M1, R). The Mott phase transition results in a reversible shift of VO2 between semiconductive and metallic state and is fundamental for VO2 smart window application. The smart widow can respond to environmental temperature and the temperature can be regulated in a wide range (usually 10-90℃) by a series techniques. This review focuses on the research development of VO2 flexible foils for application to the used glass. The key techniques involved in VO2 flexible foils are discussed, including the synthesis, surface modification, dispersion of VO2 nanoparticles and nano-printing, along with optical and service performance and energy efficiencies. This review also makes prospective on the further development and commercial application of the foils.