On the transport of excess charge carriers in polymers

The general aspects of the transport of excess charge carriers in polymers are considered. Published data on transient radiation-induced conductivity of polymers, including the model polymer poly(vinylcarbazole), are analyzed. It was shown that these data provide evidence for the nonequilibrium (dispersive) transport of charge carriers over the entire experimentally accessible range of observation time (from tens of nanoseconds to tens of minutes at room temperature). Using poly(vinylcarbazole) as an example, it was found that the dispersive transport of holes is also supported by the time-of-flight measurements, provided, however, that special precautions are taken to exclude undesirable methodological effects. The transport parameters are given for some polymers and the drift displacements of the majority carriers in them are calculated for several time intervals. Reasons for the unique photoelectric properties of poly(vinylcarbazole) are discussed.