High‐Performance Thermochromic VO2‐Based Coatings Deposited by Roll‐to‐Roll High‐Power Impulse Magnetron Sputtering

Abstract

Thermochromic vanadium dioxide (VO2) undergoes a reversible semiconductor‐to‐metal transition, a property that can be exploited for reduction of the energy consumption in buildings using smart windows. Herein, high‐performance thermochromic three‐layer ZrO2/V0.98W0.02O2/ZrO2 coatings prepared on ultrathin flexible glass (0.1 mm) without any post annealing in a pilot‐scale roll‐to‐roll deposition device are presented. The V0.98W0.02O2 layers are deposited using a reactive high‐power impulse magnetron sputtering with an oxygen flow control at a substrate temperature of approximately 350 °C. The optimized coatings (width of 0.3 m and length over 2.6 m) exhibit a transition temperature of 28 °C, an integral luminous transmittance over 50%, and a modulation of the solar energy transmittance of about 10%. The deposition process is optimized, and the elemental composition (Rutherford backscattering spectrometry), design (field‐emission scanning electron microscopy), phase composition (X‐ray diffraction), and thermochromic properties (spectrophotometry) of these high‐performance VO2‐based coatings in the context of potential for commercial applications are characterized.