Preparation and characterization of electrochromic polyaniline (PANi) thin films

Thin film of Polyaniline (PANi) was electrochemically deposited at constant potential of +0.75 V for 60 s. The surface morphology of the prepared thin film was imaged using Field Emission Scanning Electron Microscopy (FESEM). The electrochemical measurements such as electrochemical behavior and electrochemical stability were measured using Cyclic Voltammetry (CV) technique. The result showed that the thin film of PANi has good stability and reversibility. It was also found that the thin film was electroactive, well-adhered and not diffusion limited. The UV-Vis-Near IR spectra showed that the transmittance in the visible light region of the yellow colored LB (V_applied = -0.4 V) was the highest with about 60% followed by green colored ES (V_applied = +0.3V) with nearly 50% transmittance and blue colored EB (V_applied = +0.8 V) with about 30% transmittance. The spectra also revealed that the green colored ES has low transmittance of IR radiation while allows fairly enough visible light to get through (about 50% transmittance). The film is a promising material for electrochromic devices because of its good adhesion, transparency, electrochromism and low IR transmittance.