Vibrational Spectroscopy study of doping induced charged defects in a series of α,αʹ-Dimethyl end-capped Oligothiophenes

We present some preliminary results of a vibrational spectroscopic investigation carried out on a series of α,αʹ-dimethyl end-capped oligothiophenes doped with iodine. The evolution of the doping-induced infrared bands has been followed by means of in situ FT—IR spectroscopy, by allowing thin films of neutral oligothiophenes to react with dry iodine vapours at different concentrations. FT-Raman spectra recorded on powdered samples of I2-doped α,αʹ-dimethylquinquethiophene indicate the existence of a polaron-type defect