Scattering processes between bipolaron and exciton in conjugated polymers

The scattering processes between a bipolaron and an exciton in a conjugated polymer chain are investigated by numerical simulations based on the model extended with an external electric field of Su It is found that there are two channels for these scattering processes. In one channel, the exciton is annihilated and the bipolaron dissociates into a polaron and an excited polaron. In the other channel, the bipolaron and the exciton are converted into each other. Furthermore, the probabilities for these two channels are calculated, and we found that they depend sensitively on the strength of the electric field. Our results show that the interactions of bipolaron-exciton open a channel to enhance the quantum efficiency of electroluminescence due to radiative decay of the excited polaron.