The low-lying excited states of luminescent conjugated polymers: theoretical insight into the nature of the photogenerated species and intersystme crossing prcesses

摘要

In this contributin,we first discuss the nature o the primary photoexcited species in the lowest excited state of lumninescent conjuated polymers (for instance,polyparaphenylene wnylene,PPV) on the basis of quantum-chemicstyr calculations inlcuding both electrionphonon coupling and eelctron-electron interactions.We conclude that elecronic excitaitons in long PPV chains lead to the formaton of weakly bound polaron -excitons.TIN agreement with a large number of reent experimental measruemetns.We then descriebe singlet and triplet excited state in oilgothiophenes and point to the importance of interesystme crossing as an eficient nonradiative decary process of the singlet excitations.