MAGNETOOPTICAL STUDIES OF PHOTOEXCITATIONS IN CONDUCTING POLYMERS WITH DEGENERATE AND NONDEGENERATE GROUND-STATE

The nature of photoexcitations in conducting polymers has been elucidated by the absorption detected magnetic resonance (ADMR) technique. We have studied spin states in the degenerate ground state trans (CH)x and in poly(paraphenylene-vinylene) (PPV) with non-degenerate ground state. We have verified that the charged excitations are solitons in t-(CH)x and bipolarons in PPV. The long-lived neutral excitations, however, are self-trapped triplet excitons in PPV, which in t-(CH)x they dissociate into neutral soliton pairs due to its degenerate ground state structure.