Determination of mobilities of charge carriers in electrochemically anion-doped polythiophene film

Mobilities of positive charge carriers in a polythiophene film at different oxidation stages are evaluated on the bases of elaborate electrochemical measurements. The mobility in the low doping regime, most likely that of polarons, is 10−6 cm2 V−1 s−1. The mobility starts to increase at around 0.2 mol% doping level and reaches 0.5×10−2 cm2 V−1 s−1 in the heavily doped region. The drastic mobility increase by doping manifests changes in nature and/or kind of charge-carrying species, or the switching of conduction mechanisms in the ClO4--doped polythiophene film.