Transient photocurrents and steady-state conductivities in surface-doped polyanilines

Steady-state dark currents and transient photocurrents were measured in polyaniline (PANI) and poly(o-methoxyaniline) (POMA), asymmetrically protonated on one surface with various acids. In both polymers a rectification behaviour was found, indicating that the doped surfaces of the samples act as contacts injecting holes into the undoped bulk. Well defined transit times were measured in POMA: ambient-temperature hole mobility, estimated from the experiments, amounts to ca. 3×10−4 cm2/Vs. Shapes of transient photocurrent-time dependences in PANI were featureless and decaying monoexponentially to their steady-state values, with the time constants of the order of 10−2s.