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/C 70-AA systems, the electron-mediating process from C 60.- and C70.- to OV2+ occurs yielding the viologen radical cation (OV.+) with longer lifetime.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry