Effect of electron-electron interaction on polarization process of exciton and biexciton in conjugated polymers

Abstract

Abstract By using the one-dimensional tight-binding model modified to include electron-electric field interaction and electron-electron interaction, we theoretically explore the polarization process of exciton and biexciton in cis-polyacetylene. The dynamical simulation is performed by adopting the non-adiabatic evolution approach. The results show that under the effect of moderate electric field, when the strength of electron-electron interaction is weak, the singlet exciton is stable but its polarization presents obvious oscillation. With the enhancement of interaction, it is dissociated into polaron pair, the spin-flip of which could be observed through modulating the interaction strength. For the triplet exciton, the strong electron-electron interaction restrains its normal polarization, but it is still stable. In case of biexciton, the strong electron-electron interaction not only dissociate it, but also flip its charge distribution. We also calculate the yield of the possible states formed after the dissociation of exciton and biexciton.