Excitonic and polaron/bipolaronic interactions in fullerene - conducting polymer systems

Abstract

Summary form only given. Self-localized (SL) excitations of conducting polymeric chain: exciton-polarous (Ex-P),solitons (S/spl deg/, S), polaron/bipolarons (P/BP) are shown to exhibit various types of interactions with the C/sub 60/ weak dopants, (which have LUMO level within the band gap of conducting polymer) including charge transfer and Coulomb interactions. The self trapping of charges and excitation into string-type polaron/bipolarons within C/sub 60/ molecule plays important role in the stabilization of charge transfer from polymer chain to C/sub 60/ due to orientational suppression of backward electron recombination processes. We discuss the reactions of Ex-P dissociation at the neutral C/sub 60/ and the charged C/sub 60//sub -/ dopant: (Ex - P) + C/sub 60/ = P/sub +/ + C/sub 60//sub -/ , (Ex - P) + C/sub 60//sub -/ = P/sub +/ + C/sub 60//sub 2-/ as the origins for photoinduced charge transfer to C/sub 60/ with formation of charged P+s , which contribute to enhanced photoconductivity and photoluminescence quenching in C/sub 60/-doped conducting polymers. Here we analyse also other types of interactions and intercharging reactions between charged (P/BP, S) and neutral (S/spl deg/, Ex-P) excitations with P/BP on C/sub 60/ molecules intercalated between chains of conducting polymer and discuss in compsarison with our recent experimental results on electrochemically controlled charge transfer.