Characterization of semiconductor properties of polybithiophene film electrodes in contact with aqueous electrolytes. A combination of electrochemical impedance spectroscopy and photocurrent measurements

In this paper, the feasibility for investigations of the redox behaviour of electrochemically prepared polybithiophene film electrodes in contact with aqueous solutions is demonstrated. The characterization of semiconductor p roperties of the polymer is demonstrated by Electrochemical Impedance Spect roscopy (EIS) and Photocurrent measurements in dependence of the electrode potential. EIS was employed to determine the polymer resistance and the cap acitance as a function of the potential, The resulting Mott-Schottky plot o f the polymer capacitance describes the reduced (neutral) polymer as a p-ty pe semiconductor with a flat band potential of about 600 mV (vs SCE). Photo current measurements confirmed these results. (C) 1999 Published by Elsevie r Science Ltd. All rights reserved.