title: Photoinduced electron-transfer in perylenediimide triphenylamine-based dendrimers: single photon timing and femtosecond transient absorption spectroscopy.
abstract: The excited state dynamics of two generations perylenediimide chromophores substituted in the bay area with dendritic branches bearing triphenylamine units as well as those of the respective reference compounds are investigated. Using single photon timing and multi-pulse femtosecond transient absorption experiments a direct proof of a reversible charge transfer occurring from the peripheral triphenylamine to the electron acceptor perylenediimide core is revealed. Femtosecond pump-dump-probe experiments provide evidence for the ground state dynamics by populating excited vibronic levels. It is found by the means of both techniques that the rotational isomerization of the dendritic branches occurs on a time scale that ranges up to 1 ns. This time scale of the isomerization depends on the size of the dendritic arms and is similar both in the ground and excited state.
authors.affiliation: Department of Chemistry and Institute of Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, 3001 Heverlee, Belgium.
authors.forename: Eduard
authors.initials: E
authors.lastname: Fron
authors.forename: Roberto
authors.initials: R
authors.lastname: Pilot
authors.forename: Gerd
authors.initials: G
authors.lastname: Schweitzer
authors.forename: Jianqiang
authors.initials: J
authors.lastname: Qu
authors.forename: Andreas
authors.initials: A
authors.lastname: Herrmann
authors.forename: Klaus
authors.initials: K
authors.lastname: Müllen
authors.forename: Johan
authors.initials: J
authors.lastname: Hofkens
authors.forename: Mark
authors.initials: M
authors.lastname: Van der Auweraer
authors.forename: Frans C
authors.initials: FC
authors.lastname: De Schryver