Study and development of conducting polymer-based electrochromic display devices

The electrochromic response of conducting polypyrrole (PPy)/Prussian blue (PB) and conducting polyaniline (PANI)/Prussian blue (PB) composite films has been studied in different electrolytes such as KCl, LiClO4, K2SO4, KNO3, KI/I-2, etc, by depositing the PB films on top of the conducting PPy and PANI films-all prepared by electrochemical methods. The results show that the use of PB on PPy and PANI not only yields high contrast but also extends the electrochromic response to a wider region of the visible spectrum, thus working as a sensitizer for improving the electrochromic response of the conducting PPy and PANI. These electrochromic films have been characterized by other physicochemical characterization techniques such as cyclic voltammetry, SEM, XPS, XRD, etc. The electrochromic behaviour of the PPy/PB composite system has been described in detail. Electrochromic display devices using solid polymer electrolytes, which are directly useful for commercial production of such devices are currently under study. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved.