Resonant Raman identification of the polaronic organization in PANI

All solid state electrochromic devices (ECD) using polyaniline (PANI) and WO3 separated by a polymer electrolyte, PAMPS, were studied by Raman spectroscopy. The use of a blue laser line allows to isolate the spectral features corresponding to reduced PANT and in particular to follow the first steps of the charge mechanisms. On the contrary, the red line allows to investigate the phenomena associated to the oxidized and charged forms of polyaniline, and the formation of bronze in the WO3 electrode. In such devices with several layers, the use of different laser lines allows therefore to separate the reactions in the different electrooptically active media.