Field-induced dissociation of optical excitations in conjugated polymers

A theory of the field induced quenching of photoluminescence in films of conjugated polymers is presented. Time-resolved photoluminescence measurements show that the quenching effect evolves on a time scale from 0.5 ps to similar to 100 ps after excitation. This ultrafast temporal behavior of the quenching process is explained in terms of a field-assisted dissociation of localized neutral singlet excitations into geminate electron hole pairs while undergoing a random walk among polymer segments. The model considers photocarrier generation as a secondary process resulting from exciton dissociation.