Transport of photogenerated carriers in poly N-vinylcarbazole

Abstract

Thermally stimulated current (TSC) data for PVK are interpreted according to a model which is independent of the distinction between hopping conduction and band transport. Although TSC structure shifts with both heating rate and applied field, the activation energy is found to shift with field only, as expected. Activation energy and transit time are found to agree with time-of-flight results in magnitude and less well in field dependence. In addition, TSC structure is found to contain information about the distribution of hopping transport parameters. Techniques for ascertaining that TSC response is due to photogenerated carrier transport are discussed. Comparison of TSC transport energy with dielectric spectroscopy supports the suggestion that molecular rotation may play a role in hopping transport.