Electrochemical doping in a series of α,α′-dimethyl end-capped oligothienyls -: An FT-Raman confirmation of a radical cation generation

We present the results of a vibrational spectroscopic study carried out on films of a series of alpha,alpha'-dimethyl-oligothiophenes electrochemically oxidized at different anodic potentials. The Fourier transformed infrared and Raman spectra have been recorded at room temperature. The near-infrared Raman spectra, when combined with the electronic absorption data, indicate existence of radical cations in the oxidized oligomers. The dispersion of the doping induced bands with the chain length is utilized to elucidate the size of the charged defects in these oligothienyls. (C) 1998 Elsevier Science B.V.