Strategies for Enhanced Optical Performance and Durability of VO2-Based Thermochromic Windows

Due to the growing need for smart windows for buildings to reduce energy usage, vanadium dioxide (VO 2 ) has been investigated as a potential material for thermochromic smart windows due to its ease of implementation and simplicity in industrial production. VO 2 undergoes a reversible phase shift from a monoclinic (M, P21/c) semiconductor to a rutile (R, P42/mnm) metal at a critical temperature of 68 °C. This transition is accompanied by acute variations in IR reflectance, transmittance, and electrical resistance. Despite substantial developments in thermochromic materials, their optical and transition properties are still unsatisfactory. In the past several decades, many methods for enhancing optical properties have been reported, including composite films, multilayer structures, and element doping. Recent developments in thermochromic smart windows to improve both optical properties and durability have been surveyed in this review. Additionally, future growth trends have been provided by the possibility of commercially manufacturing VO 2 smart windows.