IN-SITU FTIR-ATR SPECTROSCOPIC INVESTIGATIONS ON THE REDOX BEHAVIOR OF POLY(THIENYLPYRROLE) THIN-FILM ELECTRODES IN NONAQUEOUS SOLUTIONS

Using in situ FTIR attenuated total reflection (ATR) spectroscopy, the electrochemical redox processes of poly(thienylpyrrole) (PTP) in acet onitrile (AN) solutions containing Bu-4/NClO4 or Bu4NPF6 were investig ated. The spectra of PTP based on electrochemically induced structural changes are presented. At higher oxidation levels, a delocalization o f the positive charge along the polymer chain is induced to a signific ant content and the intensities of IR active vibrational (IRAV) bands are dramatically increased. The relations of the intensities of IRAV b ands to the oxidation potential show that at lower anodic potentials t he initial charge-carrier species are polarons, while at higher potent ials (>300 mV), bipolarons are also formed coexisting with the polaron s. At potentials >500 mV only bipolarons exist. By comparing the inten sity ratios of some characteristic bands, different conductivities of the films were observed in situ.