Facile Synthesis of Island-like ZrO(2)-VO(2) Composite Films with Enhanced Thermochromic Performance for Smart Windows

VO(2)-based film, as a very promising thermochromic material for smart windows, has attracted extensive attention but has not been widely applied because it is difficult to simultaneously improve in terms of both solar-modulation efficiency (ΔT(sol)) and visible transmittance (T(lum)) when made using the magnetron-sputtering method, and it has poor durability when made using the wet chemical method. Herein, island-like ZrO(2)-VO(2) composite films with improved thermochromic performance (ΔT(sol): 12.6%, T(lum): 45.0%) were created using a simple approach combining a dual magnetron-sputtering and acid-solution procedure. The film’s ΔT(sol) and T(lum) values were increased initially and subsequently declined as the sputtering power of the ZrO(2) target was raised from 30 W to 120 W. ΔT(sol) achieved its maximum of 12.6% at 60 W, and T(lum) reached its maximum of 51.1% at 90 W. This is likely the result of the interaction of two opposing effects: Some VO(2) nanocrystals in the composite film were isolated by a few ZrO(2) grains, and some pores could utilize their surface-plasmon-resonance effect at high temperature to absorb some near-infrared light for an enhanced ΔT(sol) and T(lum). More ZrO(2) grains means fewer VO(2) grains in the composite film and increased film thickness, which also results in a decrease in ΔT(sol) and T(lum). As a result, this work may offer a facile strategy to prepare VO(2)-based films with high thermochromic performance and promote their application in smart windows.