Tracking the optical constants of porous vanadium dioxide thin films during metal–insulator transition: Influence of processing conditions on their application in smart glasses

Vanadium dioxide (VO2) is widely recognized as a thermochromic material with great potential for application in smart glazing energy-efficient buildings. The monoclinic (M1) VO2 phase undergoes first-order reversible transition from the semiconductor to rutile metallic state. In this study, an M1 porous film was synthesized via polymer-assisted sol-gel route. Processing parameters, such drying and reduction temperatures, were varied evaluate their influence on behavior of determine necessary trade-off between significant effect high luminous transmittance. Film–silica glass–film systems transmittance close 80% IR solar modulation ability large 20% prepared. By tracking optical constants films during process, changes produced at microscopic level could be correlated its macroscopic when used energy-saving material.