Hopping transport in a molecularly doped organic polymer

Abstract

Electronic transport in the polycarbonate polymer Lexan molecularly doped with triphenylamine (TPA) has been studied by time-of-flight techniques as a function of temperature, applied field, and TPA concentration. Only hole transport could be observed. The experimental data provide evidence that the transport of holes occurs by a hopping process which connects sites associated with the TPA molecule. The results are analyzed in terms of the theory of stochastic non-Gaussian transport by Scher and Montroll. This theory provides a consistent description of all experimental results if field-induced barrier lowering and temperature-dependent dispersion are formally introduced in the final expression for the transit time.