Optimized Atmospheric-Pressure Chemical Vapor Deposition Thermochromic VO₂ Thin Films for <i>Intelligent</i> Window Applications

Abstract

Monoclinic vanadium(IV) oxide (VO₂) has been widely studied for energy-efficient glazing applications because of its thermochromic properties, displaying a large change in transmission of near-IR wavelengths between the hot and cold states. The optimization of the reaction between VCl₄ and ethyl acetate via atmospheric-pressure chemical vapor deposition (APCVD) was shown to produce thin films of monoclinic VO₂ with excellent thermochromic properties (Δ<i>T</i> _sol = 12%). The tailoring of the thermochromic and visible light transmission was shown to be possible by altering the density and morphology of the deposited films. The films were characterized by X-ray diffraction, atomic-force microscopy, scanning electron microscopy, ellipsometry, and UV-vis spectrometry. This article provides useful design rules for the synthesis of high-quality VO₂ thin films by APCVD.