Thermochromic and photocatalytic properties of thermally evaporated vanadium oxide-molybdenum oxide mixed oxide thin films

Vanadium Oxide-Molybdenum Oxide (VO-MO) mixed oxide thin films of 500 nm thickness with different compositions of VO75% MO25%, VO50% MO50%, and VO25% MO75% are coated on quartz substrate by thermal evaporation technique. The prepared composite thin films showed good thermochromic properties while heating and remarkable reversible properties while bleaching. The transition temperature of the composite thin film (500 nm thickness) with a composition of VO50% MO50% was 29 degrees C and that of VO75% MO25% was 64 degrees C and that of VO25% MO75% was - 13 degrees C. It is clear that the VO50% MO50% composite thin film showed a better transition temperature that is near room temperature. All the three composite thin films showed metamaterial properties in a small range of temperatures and also the composite thin films exhibited good photocatalytic performance on methylene blue (MB) dye degradation under direct sunlight irradiation. However the composite thin film VO50% MO50% (when compared to VO75% MO25% and VO25% MO75% thin films) showed better photocatalytic performance of about 46% of MB dye degradation when exposed to sunlight for 120 min. Hence the obtained composite thin film (VO50% MO50% ) with both thermochromic and photocatalytic properties can play a crucial role to develop technological advancement in eco-friendly building applications.