Reactions at the two sides of an ECD device studied by Raman spectroscopy

An all solid-state electrochromic device (ECD) using polyaniline (PANI) for anodic coloration and tungstic acid WO3, 2 H2O for cathodic coloration, separated by a polymer electrolyte (PAMPS), presents very good performances. To check the sequences of the protonation /deprotonation and oxidation /reduction reactions arising in fee two optically active materials, Raman spectroscopy was used on the two sides of the ECD. An improvement of fee PANI crystalline order due to fee interfacing with PAMPS, especially using PANI doped wife camphorsulfonic acid (PANI-CSA) is observed, which is one of fee reasons of fee excellent performances of fee device. The free electrons injection in fee device, which is fee key of their good reversibility, is ensured at high potentials by the cathodic tungsten bronze, and at moderate potentials by fee anodic leucoemeraldine salt;