Synthesis of colloidal VO 2 nanoparticles for thermochromic applications

Abstract Vanadium dioxide (VO 2 ) thin films are key materials for thermochromic smart windows and commonly have a typical phase transition (insulator to metal phase) at a transition temperature of 68 °C. This research, however, found that highly crystallized VO 2 nanoparticles can be successfully coated on a glass substrate with added functionalities, such as higher luminous transmittance and transition efficiency. The transition temperature revealed that the VO 2 nanoparticles with post thermal treatment at 600 °C also clearly exhibited a reduced transition temperature of 69 °C in the heating curve, 59 °C in the cooling curve, and a transition width of 10 °C. By nanopatterning the thin films, we were able to prepare VO 2 thin films with higher luminous transmittance than that attained with non-patterned VO 2 thin films. The enhanced transition property was demonstrated using highly crystallized VO 2 nanoparticles induced by post thermal treatment, and the luminous transmittance was improved by the nanopatterns on the surface of the VO 2 thin films.