SPECTROELECTROCHEMICAL BEHAVIOR OF POLY(3-OCTYLTHIOPHENE) - APPLICATION TO ELECTROCHROMIC WINDOWS WITH POLYANILINE AND IRIDIUM OXIDE

The spectroelectrochemical behaviour of cast poly(3-octylthiophene) (P OT) films (0.2 and 0.5 mu m) on indium-tin-oxide (ITO) glass electrode s has been investigated in organic media. These thin films exhibit int eresting electrochromic properties and their application in electrochr omic devices has been examined in liquid (CH3CN + LiClO4 0.3M) and vis cous electrolyte (PEO + CH3CH + LiClO4). Polyaniline (PANI) him appear s to be a convenient complementary counter electrode since its transmi ssion maximum corresponds to its oxidized state and that of POT film t o its reduced state. Thin films of iridium oxide (IrO2) are also possi ble counter electrodes, even in acetonitrile, the electrochemical beha viour being mostly capacitive with a low transmission change. However, the best contrast is obtained with the POT/PANI system.