title: Solvatochromic effects on the photoinduced charge-transfer states in donor-acceptor substituted polydioctylfluorenes.
abstract: Polymer morphology affects quantum efficiency. The influence of polymer morphology on the emission from charge transfer states within donor-acceptor (D-A) polydioctylfluorene derivatives is investigated. Two D-A copolymers, comprising one- and two-electron-donating triphenylamines substituted into the electron-accepting dioctylfluorene repeat unit were studied. Time-resolved emission spectra (with a resolution of 330 fs) in both liquid and glass phase isolate nuclear relaxation to the large-amplitude motion of the triphenylamine moiety about the single bond, analogous to the twisted intramolecular charge-transfer (TICT) model. The charge separation in the polymers' emitting states is therefore increased, suggesting a potential approach to enhance quantum efficiency in devices otherwise limited by exciton recombination.
authors.affiliation: Cavendish Laboratory, University of Cambridge, J. J. Thompson Avenue, Cambridge CB3 0HE, UK. carylrichards@cantab.net
authors.forename: Caryl E
authors.initials: CE
authors.lastname: Richards
authors.forename: Richard T
authors.initials: RT
authors.lastname: Phillips