Design and characterization of a three-electrode electrochromic device, based on the system WO3/IrO2

We present here the design and the characterization of a three-electrode el ectrochromic device (ECD) based on the WO3/IrO2 system. An Ag/AgCl pseudore ference was designed to be incorporated in the thin polymeric layer of elec trolyte separating the electrochromic WO3 electrode from the IrO2 counter-e lectrode. This reference electrode enabled an in situ characterization of t he WO3 and IrO2 materials, thereby helping in understanding the electrochem ical mechanisms arising at each electrode during cycling. The reliability o f such three-electrode measurements was also demonstrated by comparing the results obtained in liquid electrolyte with those obtained in the thin film polymer-based ECD. (C) 1999 Elsevier Science Ltd. All rights reserved.