Annealing effects of NiO thin films for all-solid-state electrochromic devices

• Published in: Solid state ionics 2017-07, Vol.305, p.43-51
• Main Authors: Atak, Gamze, Coşkun, Özlem Duyar
• Format: Article
• Language: English
• Subjects: Annealing temperature; Coloration efficiency; Electrochromic device; Nickel oxide; Optical modulation; RF magnetron sputtering
• ISSN: 0167-2738; 1872-7689
• DOI: 10.1016/j.ssi.2017.05.002

Nickel oxide (NiO) thin films were deposited onto glass substrates and ITO-coated glass substrates by RF magnetron sputtering using a NiO target in pure argon (Ar) atmosphere at room temperature. The chamber working pressure was kept at 15mTorr and deposition power was 75W during the deposition processes. The films were annealed for 2h between 100°C and 400°C in air ambient. The optical, structural and electrochromic properties were investigated by optical spectrophotometry, X-ray diffraction, atomic force microscopy and electrochemical measurements of the samples, respectively. Effects of the heat treatment on the optical constants of the films were analyzed in detail. Coloration efficiencies and optical modulations of the films were estimated for a wide spectral range. The amount of inserted/extracted and residual charges of the films during the bleaching/coloring process was calculated as a function of annealing temperature. Finally, a custom design all-solid-state electrochromic device was fabricated using the NiO film as an anodic layer developed on this study. •Effect of heat treatment on optical, structural and electrochromic properties of the NiO thin films were analyzed in detail.•Coloration efficiencies and optical modulations of the films were obtained for a wide spectral range.•A custom design all-solid-state electrochromic device was fabricated.•The optical modulation of the device was about 34% at 550nm