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 (Δ T 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 (Δ T 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 Δ T 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. Δ T 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 Δ T 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 Δ T 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.