Large-Scale Preparation of Durable VO2Nanocomposite Coatings

Abstract

Vanadium dioxide (VO2) glass is a promising thermochromic smart energy-saving window. Many studies have been carried out for improving its optical performance, but for practical applications, the weatherability and large-scale preparation still remain as obstacles. In this work, the failure mechanism of VO2 nanoparticles at room temperature was analyzed, a new formulation of the VO2 nanocomposite coatings was designed to improve the coatings' weatherability, and a continuous roll-coating method was developed for large-scale preparation. The process is an all-solution-based low-temperature (240 °C) method and has no specific requirements for atmosphere. The size of the samples prepared using the current method is as large as 1.2 × 1.0 m2. The prepared samples showed significantly improved weatherability compared to a reported water system (sixfold increase in moisture resistance test), excellent optical performance with a phase-transition temperature of 30 °C (Tlum = 55.0 % (10 °C) and 51.0 % (70 °C) and δ Tsol = 16.6%), and phase-transition stability (less than 5% performance loss after 7000 cycles).