Study of polyaniline and functionalized ZnO composite film linked through a binding agent for efficient and stable electrochromic applications

A highly stable electrochromic film based on a composite of polyaniline with surface functionalized zinc oxide nanoparticles has been prepared by electrochemical polymerization. Core shell type structure was obtained by preferential polymerization of aniline around ZnO linking through (3-Aminopropyl)trimethoxysilane (3-APTS), as confirmed by High resolution transmission electron microscopy (HRTEM) investigations. Electrochemical and electrochromic properties were investigated using cyclic volatammetry, chronoamperommetry, electrochemical impedance spectroscopy (EIS) and UV-vis spectroscopy. The composite exhibited enhanced stability of 104 cycles with high coloration efficiency of 89 cm2C−1 and found to have superior (65%) optical contrast. As compared to pristine polyaniline, the response time reduces from 1.3 s to 0.4 s for coloration and from 1.7 s to 0.8 s for bleaching. A mechanism for its improved stability has been proposed. The pani-fZnO hybrid seems to be a potential candidate for anodically coloring electrochromic material.