Effects of Zn-dopant on structural properties and electrochromic performance of sol-gel derived NiO thin films

Abstract

Zn-doped NiO thin films were prepared by sol-gel spin-coating method onto transparent conducting substrates using nickel acetate tetrahydrate and zinc acetate dehydrate as starting precursors. Effects of zinc doping content on the structural, optical and electrochromic properties of NiO films were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, field emission-scanning electron microscope, atomic force microscopy, UV-VIS spectrophotometer and cyclic voltammetry. The results reveal that Zn doping has significant influence on crystallinity deterioration, surface topography alternation and electrochromic performance of the films. The expansion of active surface area due to reduced crystallinity of the films resulting to the increase of charge transfer in the electrochemical reaction. It is indicated that electrochromic performance of sol-gel derived NiO films can be ameliorated by the incorporation of Zn additive at specific content.