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The two-photon fluorescence properties and ultrafast responses of a hyperbranched polyyne(hb-DPP-J2)with triphenylamine as the central core,Diketo-Pyrrolo-Pyrrole as the connecting unit and electron acceptor are studied.The polymer has a D-π-A-π-D conjugated structure along the extended polyyneπ-bridge systems,and the effective conjugated unit repeats itself in the whole hyperbranched polymer chain.The polymer exhibits a large two-photon absorption cross section and high fluorescence quantum yields.The ultrafast dynamic results give a deep understanding of the excited energy transfer processes under excitation,and reveal a long relaxation lifetime of the intramolecular charge transfer(ICT)state.
The two-photon fluorescence properties and ultrafast responses of a hyperbranched polyyne (hb-DPP-J2) with triphenylamine as the central core, Diketo-Pyrrolo-Pyrrole as the connecting unit and electron acceptor are studied. The polymer has a D-π- A-π-D conjugated structure along the extended polyyneπ-bridge systems, and the effective conjugated unit repeats itself in the whole hyperbranched polymer chain. The polymer exhibits a large two-photon absorption cross section and high fluorescence quantum yield. The ultrafast dynamic results give a deep understanding of the excited energy transfer processes under excitation, and reveal a long relaxation lifetime of the intramolecular charge transfer (ICT) state.