Intrachain charge generation and recombination in alkoxy-substituted poly-(p-phenylenevinylene) films - art. no. 205205

The role of intrachain processes in ultrafast charge photogeneration has be en investigated in solid state for two dialkoxy PPV derivatives, characteri zed by an open-chain and a closed-chain substitution, respectively. In spit e of the different strength of the intermolecular interaction induced by th e chemical structure of substituents. similar relaxation dynamics are obser ved in the first few ps. Two main relaxation pathways are individuated. Upo n excitation, single-photon absorption processes generate singlet excitons. whose relaxation dynamics is initially governed by intrachain diffusion. T wo-step absorption processes are responsible for generation of high-energy excited states, which decay towards intrachain charge-transfer states on a time scale faster then our temporal resolution. Ultrafast charge recombinat ion is then observed in the first hundreds of fs.