Quenching of pyrene fluorescence by fullerene C60 in Langmuir-Blodgett films

Langmuir-Blodgett (LB) layers of pyrene and C-60 mixed with tricosanoic acid have been built-up on quartz substrates. The optical properties of the films were characterized using time-correlated single-photon counting, and absorption and steady-state fluorescence spectroscopy. Observation of negligible overlap between the emission of the donor (pyrene) and the electronic absorption spectra of the acceptor (C-60) indicates that the observed fluorescence quenching of the donor in the presence of the strong acceptor is due mainly to photo-induced electron transfer (PET) with no significant energy transfer process. The PET has been investigated by monitoring the quenching of monomer and excimer pyrene fluorescence in mixed LB films containing different concentrations of C-60. (C) 1997 Elsevier Science B.V.