Facile fabrication of VO2/SiO2 aerogel composite films with excellent thermochromic properties for smart windows

In order to improve the solar modulation ability and near-infrared shielding performance of VO2-based films, in this work, VO2/SiO2 aerogel composite films have been fabricated by a facile mechanical ball-milling method. It has been clarified that the solar modulation efficiency (Delta Tsol) of the composite film can be increased by 187.5% (from 6.4% to 18.4%) by introducing SiO2 aerogel into the composite film when the visible light transmittance (Tlum) is about 40%, which can be ascribed to the synergistic effect of Rayleigh scattering effect of SiO2 aerogel and the good dispersion of the particles. The VO2/SiO2 aerogel composite particles not only have excellent dispersion, but also the SiO2 aerogel can effectively slow down the oxidation of VO2 and improve the oxidation resistance of VO2. In particular, the universality of the Rayleigh scattering effect of SiO2 aerogel is demonstrated, which can act together with the doping effect of Mg2+ ions to further improve the thermochromic properties of VO2 films. This study provides a new idea for improving the thermochromic properties of VO2 films and meanwhile is of great significance in promoting the practical application of VO2 films in the field of smart windows.