DefinePK

Abstract

Electrochromic films based on nickel hydroxide have been deposited from Ni(NO3)2 solution employing cathodic template synthesis. Polyvinyl alcohol has been used as a template. The influence of deposition time (10, 20, 40 and 80 min) on electrochromic and electrochemical properties of the film had been studied. By means of scanning electron microscopy and atomic force microscopy it was determined that prepared films are uniform, its morphology is independent of substrate morphology, surface bumps are 30-100 nm in diameter and their height is below 180 nm. By mean of X-ray diffraction analysis established that film consists of highly defective a-Ni(OH)2 with low crystallinity. Electrochemical and electrochromic properties of films prepared at different deposition times have been studied by means of cyclic voltammetry with simultaneous recording of bleaching-coloration curves. Analysis of bleaching-coloration curves has revealed high reversibility of the process. It was also discovered that in series of deposition times 10 - 20 - 40 - 80 min, the average coloration degree was 0.3 - 0.5 - 0.65 - 0.75, which corresponds to 70% - 31% - 17% increase in coloration degree. As such, the optimal deposition time for nickel hydroxide films at a current density of 0.625 mA/cm2 is 40 - 80 min (film thickness 2.58 - 5.16 µm).