Mist CVD of vanadium dioxide thin films with excellent thermochromic properties using a water-based precursor solution

Mist chemical vapor deposition (mist CVD), which is capable of producing oxide films over large areas at a high productivity and low cost, has been proposed as a fabrication method for VO2 thin films for smart windows. However, the thermochromic properties of the VO2 films previously prepared by mist CVD are not sufficient for application in smart windows. In this study, to obtain a high-quality VO2 film, we investigated the effects of the solvent of the precursor solution on the resulting film in mist CVD. Films consisting of a single phase of VO2 were obtained when a water-based precursor solution was used. In contrast, V2O3 films are formed when a methanol-based precursor solution is used. The VO2 film deposited from water solution exhibited high visible transmittance along with a large change in the infrared transmittance with temperature change. The high quality of the VO2 film indicates that mist CVD is an effective method for the fabrication of VO2-based smart windows.