Hot exciton dissociation in a conjugated polymer

A model has been developed to treat field-assisted ultrafast on-chain disso ciation of optical excitations in a conjugated polymer. Conversion of the e xcess photon energy above the singlet exciton into the vibrational heat bat h of a polymer segment is considered as a main source of the energy require d fur charges to escape from a potential well formed by a superposition of the Coulomb and external electric fields. The calculated yield of carrier p hotogeneration increases strongly with increasing field but is independent of the temperature in good quantitative agreement with data obtained by Ear th er nl. [Chem. Phys. Lett. 288, 147 (1998)] on weakly disordered conjugat ed ladder-type poly-phenylene. [S0031-9007(98)08372-0].