Separated analysis of bulk and contact resistance of conducting polymers: Comparison of simultaneous two- and four-point measurements with impedance measurements

Simultaneous measurements of conductive polymer by two-and four-point techniques were used for evaluation of the contact resistance for the polymer/metal interface. An experimental validation of this approach was performed for polypyrrole electrochemically deposited on gold electrodes. The dependence of contact resistance on the electrode potential versus reference electrode was measured. The results were compared with the corresponding dependence obtained from impedance spectroscopy. Both techniques provide almost identical data while the new approach is easier, faster and independent on selection of equivalent circuits.