Electronic defect studies of ladder-type polymers

Electrically active defects have a profound impact on the semiconducting properties of conjugated polymer systems. Defect-induced thermally stimulated current (TSC) in poly (benzimadazobenzophenanthroline), a ladder-type, high-temperature conjugated polymer, is studied in detail. The TSC results identify the nature and the energetics of the trap levels in the polymer. Variations in the results as a function of the initial trap-filling parameters and the thermal history were also observed. The long-lived component in the photoinduced current decay, an indicator of defect states, is also studied within this context. The barrier limiting processes of the photocurrent are correlated with the results obtained from TSC measurements and we speculate on the origin of these defects.