The electrochromic properties of nickel oxide by chemical deposition and oxidization

The advantages of nickel oxide as an electrochromic material are its good contrast of transmittance and its suitable use as a secondary electrochromic film with WO3 for electrochromic devices. Electrochromic nickel oxide prepared by chemical processes which include deposited nickel film by electroless (or chemical deposition) method and then oxidized by H2O2. Compared with other methods, deposited nickel oxide by chemical deposition is simple and easy to scale-up for industrial application. The morphologies of the films were examined by scanning electron microscope (SEM), atomic force microscope (AFM) and X-ray diffraction (XRD). The optical density change (Delta OD) of the films at 630 nm was 0.42, which was operated between -1.5 and + 1.5 V of potential step after 100-cycle switching. The response time for coloring and bleaching were 1.7 s and 3.3 s, respectively. The life cycles of electrochromic characteristics was recorded by using the cyclic voltammetry (CV). The superficial current density of oxidation remaining was up to 0.002 A/cm(2) after 5000 cycles. (c) 2005 Elsevier B.V. All rights reserved.