A Universal Approach To Achieve High Luminous Transmittance and Solar Modulating Ability Simultaneously for Vanadium Dioxide Smart Coatings via Double-Sided Localized Surface Plasmon Resonances

Abstract

Vanadium dioxide (VO₂)-based thermochromic coatings has attracted considerable attention in the application of smart windows as a result of their intriguing property of metal-insulator transition at moderate temperatures. However, the practical requirements of smart windows, i.e., the high luminous transmittance of <i>T</i>_lum > 60% and large solar modulating ability of Δ<i>T</i>_sol > 10%, are competing to a large extent and hardly satisfied simultaneously. Here, we proposed a facile and universal method to prepare VO₂ coatings for exceeding the criteria above using double-sided localized surface plasmon resonances (LSPRs), which are excited by the VO₂ nanoparticles dispersed evenly on both surfaces of the fused silica substrate. With subtle engineering of the sol-gel and heat treatment processes, the morphology of as-prepared VO₂ nanoparticles and corresponding LSPRs are controlled to achieve a high luminous transmittance (<i>T</i>_lum = 68.2%) and solar modulating ability (Δ<i>T</i>_sol = 11.7%) simultaneously. Further simulation suggests that the double-sided LSPRs can collectively enhance the performance of VO₂ smart coatings. Moreover, the double-sided VO₂ nanoparticle coatings demonstrate stable performance with no more than 1% degradation of <i>T</i>_lum and Δ<i>T</i>_sol after 1500 cycles. This study provides an alternative strategy to obtain high-quality VO₂ (M) solar modulating coatings.