A novel method to modify the color of VO2-based thermochromic smart films by solution-processed VO2@SiO2@Au core–shell nanoparticles

Abstract

In this study, the VO₂@SiO₂@Au core–shell nanoparticles were synthesized by a solution process to tailor the color of VO₂ films on the basis of surface plasmon resonance (SPR). The SiO₂ interlayer not only provided more hydroxyl bonding for the silane coupling agent, which was conducive to metal deposition, but also significantly improved the anti-oxidation ability of VO₂. We optimized the thickness of silica to maintain the silica layer uniform and thin (14 nm), which would impact on the optical properties. The VO₂@SiO₂@Au films with various Au particle sizes displayed a series of colors from brick red to purple and blue while maintaining the solar modulation ability (the maximum ΔT_sol is up to 7.52%). Moreover, the phase transition temperature decreased by about 6 °C without doping due to electron injection from Au to VO₂. This study proposed a novel and facile method to tune the color of VO₂-based thermochromic smart films while improving the anti-oxidation ability and decreasing the phase transition temperature. It may constitute a great advance in the development of thermochromic smart films.