Electronic absorption and emission spectroscopic investigations of the interaction of the fullerenes, C₆₀ and C₇₀, with amines and aromatic molecules

Abstract

Electronic absorption spectroscopy and fluorescence spectroscopy have been used to investigate the interaction of the fullerenes C₆₀ and C₇₀ with diethylaniline, and with aromatic solvents such as benzene. C₆₀ interacts weakly with aromatic amines in the ground state while C₇₀ does not interact at all. Steady state fluorescence emission and lifetime measurements show that both C₆₀ and C₇₀ form excited state complexes (exciplexes) with the amines in non-aromatic solvents such as methylcyclohexane, but not in benzene. In benzene, only fluorescence quenching is observed due to the interaction between the π systems of the aromatic solvent and the fullerene in the ground state. This is also borne out by the systematic study of solvent effects on the absorption and emission spectra of the fullerenes.