Electrochromic characterisation of electrochemically deposited nickel oxide films

Electrochromic hydrated nickel oxide films have been cathodically deposited onto ITO-coated glass substrates from a solution of nickel sulphate and ur ea at room temperature. The in situ measurements of the response time durin g the colouring/bleaching process are reported. The dependence of the elect rochromic properties on post-deposition heat treatment have been studied. A good optical modulation has been found for un-annealed samples, while samp les annealed at higher temperatures showed smaller modulation. The extincti on coefficient (k) has been computed from spectrophotometrically measured t ransmittance and reflectance. The structural characteristics as well as the surface morphology of some nickel oxide samples were investigated using X- ray diffraction and SEM analysis. (C) 2000 Elsevier Science B.V. All rights reserved.