Photoconductivity in amorphous polymers: An old problem revisited

Abstract

Hole transport in polyvinylcarbazole (PVK) has been the infject of many previous investigations. Earlier workers have reported significant differences between their measurements and those predicted for the continuous time random walk model (CTRW) of dispersive transport in amorphous systems. The experimental results reported here are, contrary to these earlier experimental findings, in good agreement with dispersive tranport theory. This good agreement is only found, however, using exciting light intensities two orders of magnitude below values conventionally used. In contrast to earlier results we find a single temperature independent vaule of a equal to 0.66 (±0.05). This temperature independence of a implies that hole transport is determined solely by the geometry of the amorphous polymer and not by a Boltzmann equilibrium among energy levels of the disordered system. © 1987 SPIE.