Electrochromic Thin‐Film Nickel‐Oxide Coatings for Systems with Adjustable Light Transmission

Abstract

In this study, results on the effect of technological parameters of the nickel(II)‐oxide thin‐film deposition process, obtained through chemical vapor deposition in an argon–oxygen environment using bis‐(ethylcyclopentadienyl)‐nickel (EtCp)2Ni, on their electrochromic properties, are presented. It is shown that the films lose ability to electrochromic coloring in alkaline environments as their thickness increases up to 170 nm. The introduction of small ozone additions of 0.1 vol% O3 into the gas phase leads to a decrease in the NiO films deposition rate, the formation of a rougher layer with an average grain size up to 71.4 nm, capable of coloring in light brown. Additional cathodic treatment of NiO films at a potential of −0.8 V for 30 s in alkaline environments containing fullerene C60(OH)24 leads to the modification of the surface layer and the formation of NiO–C carbon‐containing nanocomposite coatings with enhanced contrast and the ability to retain the colored state after polarization is turned off, i.e., possessing optical memory properties. Using NiO–C nanocomposite and indium–tin–oxide films, which have opposite coloring mechanisms, in the structure of an electrochromic device allows for an increase in the grade of glass darkening, significantly reducing energy consumption, improving operational characteristics, and life span.