Intra-chain exciton generation by charge recombination in substituted polyacetylenes

Nascent excited state dynamics, following photoexcitation by 25 fs optical pulses, is detected in a degenerate ground state conjugated polymer with transverse conjugation, namely poly di-phenyl acetylene. Pumping 1.1 eV above the optical gap generates correlated polaron pairs, whereas the majority of the neutral singlet excited states are formed in a secondary process upon geminate recombination of polaron pairs. When the exciting photons have lower energy, close to the optical absorption edge, only singlet states are formed. (c) 2007 Elsevier B.V. All rights reserved.