title: Photoinduced electron transfer and electron-mediating systems from aromatic amines to triplet states of C60 and C70 in the presence of a viologen dication.
abstract: Photoinduced electron transfer between fullerenes (C60 and C70) and various aromatic amines (AA's) in the absence and presence of a viologen dication has been studied by the transient absorption method in the visible and near-IR regions. Electron-transfer takes place from AA's to the triplet states of fullerenes (3C60* and 3C70*) giving the anion radicals of fullerenes (C60*- and C70*-) and the radical cations of AA's (AA*+). The rate constants and efficiencies of electron transfer are quite high, because of the high electron-donor abilities of AA's as their low oxidation potentials indicate. The absorption bands of AA*+ appeared also in the near-IR region indicating that the radical-cation center (hole) delocalizes over the entire region of each AA. On addition of an octylviologen dication (OV2+) to C60/C70-AA systems, the electron-mediating process from C60*- and C70*- to OV2+ occurs yielding the viologen radical cation (OV*+) with longer lifetime.
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, CREST, Japan Science and Technology Corporation, Katahira, Sendai, 980-8577, Japan.
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Sasaki
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Araki
authors.forename: Mamoru
authors.initials: M
authors.lastname: Fujitsuka
authors.forename: Osamu
authors.initials: O
authors.lastname: Ito
authors.forename: Akiko
authors.initials: A
authors.lastname: Hirao
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Nishizawa