Ultrafast Field-Induced Dissociation of Excitons in Conjugated Polymers

Abstract

We present a time-resolved study of the field-induced luminescence quenching in poly(phenylphenylenevinylene) using femtosecond luminescence spectroscopy. The dynamic quenching of the luminescence reveals a delay between the generation of excitons and their breakup into geminate electron-hole pairs. We explain the data by the interplay of the dissociation and the spectral relaxation of the excitons within an inhomogeneously broadened density of states. Our experimental results suggest that the photocarriers in conjugated polymers are not formed directly but result from dissociation of excitons.