Solvent effects on formation and decay of electron donor—acceptor exciplex of C70 and N,N-diethylaniline. Fluorescence quenching due to solvent polarity and polarizability

Fluorescence of C70—N,N-diethylaniline exciplex is studied in solvent mixtures of hexane—acetone, hexane—THF, hexane—ethanol, and hexane—toluene at variable compositions. The results are inconsistent with the notion that the strong solvent dependence of exciplex fluorescence is due to specific interactions such as complexation between C70 monomer and solvent molecules. It is proposed that the quenching of exciplex fluorescence in polar or polarizable solvents is due to a competing decay process that results in the formation of solvated ions.