We report time-of-flight, transient dark injection (DI) and current density
versus voltage measurements on polyfluorene copolymer diode structures usi
ng pretreated indium tin oxide: (ITO) as a hole injecting contact. For ITO
exposed to an oxygen plasma, coated in poly(ethylenedioxythiophene)/polysty
renesulphonic acid, or with both treatments, all measurements were entirely
consistent with positive carrier, trap-free, space-charge-limited current
theory. For untreated ITO, the behaviour is instead injection limited. (C)
2001 Elsevier Science B.V. All rights reserved.