Electrochromic Properties of Nanostructured WO 3 Thin Films Deposited by Glancing‐Angle Magnetron Sputtering

Abstract Tungsten oxide thin films are prepared by glancing‐angle reactive magnetron sputtering at room temperature. The surface and cross‐section morphologies are characterized by FE‐SEM and TEM. The electrochromic properties of the thin films are studied using a three‐electrode system in 1 m LiClO 4 /PC solution. When the glancing angle is kept at 80°, a nanocolumnar structured film is obtained. This nanocolumnar structured film shows a lower driving potential and better stability compared to the dense film. The charge capacity per unit area of the nanocolumnar structured film is determined to be 30.85 mc cm −2 . The diffusion rates of injection and detachment of ions are determined to be D in = 6.57 × 10 −10 cm 2 s −1 and D de = 6.55 × 10 −10 cm 2 s −1 under an applied potential of ±1.2 V, respectively. The optical modulation amplitude of the nanocolumnar structured film reaches 65% at a wavelength of 600 nm and the optical density is superior to that of the dense film.