Hole transport in polystyrene and polycarbonate doped with polar dopants

Hole transport in PS and PC doped with low-molecular-mass dopants with dipole moments larger than 3D is investigated. Both near-surface and bulk charge-carrier generation techniques are used. There is good agreement between the experimentally measured values of hole mobility and the published data. It is shown that, for the investigated systems, the hole transport is nonequilibrium and is well described by the multiple-trapping model with the Gaussian trap distribution over energy. The presence of a flat plateau on the time-of-flight curves does not necessarily mean establishment of the quasi-equilibrium hole transport in the system.