Abstract:

This work attempts to evaluate the influence of substrate conductivity on electrochromic and electrochemical properties of Ni(OH)2/PVA composite films, including coloration and bleaching rate. The conductivity of FTO glass was improved by depositing a silver gird with differing line densities. For deposition of the silver lines, aerosol jet printing method was used. As a result, few electrochromic films were deposited onto bare FTO glass and FTO glass with silver grid deposited onto it. In order to investigate deposited electrochromic films, the cyclic voltammetry with simultaneous recording of the optical characteristics is used. The optical characteristics of films were rather close to each other. At the same time, their electrochemical properties are different. It is found that the additional peaks observed is that of silver, which is electrochemically active in used potential window. In addition it was observed that during electrochemical cycling of Ni(OH)2/PVA deposited on substrates with silver grid, the last changed color from shiny metallic to black color. It is proposed that color changes of silver grid caused by silver transforming to Ag2O or AgO and back to metallic silver. It is found, that for small areas of electrochromic platings, substrate resistivity has a negligible effect on coloration and bleaching rates. The coloration and bleaching rates for Ni(OH)2/PVA films deposited onto the bare substrate, the substrate with a silver grid (1 cm cell size) and the substrate with a silver grid (0.5 cm cell size) were: –1.45, –1.71, –1.40 and 1.1, 0.75, 0.84 %∙s-1. It is suggested that the effect of substrate conductivity will clearly be seen when the physical sizes of substrate increase. Also it was underlined that for further experiments for effect definition of substrate resistivity on electrochromic properties inherit conductive materials should be used

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