Transient space-charge-perturbed current in films of poly(N-vinyl carbazole)

In the general class of polymeric solids, poly(N-vinyl carbazole), PVK, is emerging as one of the most widely studied materials. The transport of charge injected from sensitizing layers, or internally photo-generated, has been reported.
^1,2,3
All of these studies revealed that the drift mobility of holes in PVK, as measured by the time of flight of technique, is field dependent and is very low in value even at moderately high fields. The mobility μ is found to vary approximately as E
²
, with a typical value of about 10
⁻⁷
cm
²
/v sec at 10
⁵
V/cm.
^1,3
The purpose of this report is to demonstrate that this low, field dependent hole mobility manifests itself in the observation of trap-free space-charge-perturbed currents; the field and time dependence of these currents will be described.