Carrier generation mechanisms for photoconductivity in conjugated polymers

We study theoretically the origin of photoconductivity in conjugated polyme rs. The charge carriers are released when excitons dissociate through the d eep levels within the semiconductor bandgap caused by either oxidation (car bonyl group) or structure defects. Our results explain the recent observati ons of the temperature-independent photocurrent in the sweep-out regime and the transient photocurrent at high excitation. The tightly bound exciton v ersus semiconductor band controversy on the photocarrier generation process is clarified.