Effects of natural aging on the surface compositions and optical properties of thermochromic vanadium oxide films

Abstract We experimentally investigate the long-term atmospheric durability of thermochromic vanadium oxide (VOX) films. The VOX films were deposited on glass substrates by reactive direct current magnetron sputtering and were then in-situ annealed at the preparation temperature ≤350 °C. The X-ray photoelectron spectroscopy (XPS) was applied to investigate the surface compositions of the natural aged films, while the optical properties of the films were characterized by the spectrophotometer and spectroscopic ellipsometry. The XPS results reveal that the oxygen-deficient VOX (X