Fluorescence spectra and quantum yields of [60]fullerene and [70]fullerene under different solvent conditions. A quantitative examination using a near-infrared-sensitive emission spectrometer

Abstract

Absorption and emission properties of [60]fullerene and [70]fullerene in solutions of ten different solvents were studied. With the use of a near-infrared-sensitive detector, the complete fluorescence spectra of [60]fullerene and [70]fullerene were determined. The spectra extend well into the near-infrared region. The correct fluorescence quantum yields of [60]fullerene and [70]fullerene in toluene are 3.2 × 10^–4 and 5.7 × 10^–4, respectively, and the yields are slightly different in other solvents. For most applications, the fluorescence quantum yield ratio Φ_F,C70/Φ^F,C60 of 1.8 can be used as a solvent independent constant. The discrepancies between the experimentally determined transition probabilities and those calculated from observed absorption and fluorescence spectra of both [60]fullerene and [70]fullerene in terms of the Strickler–Berg equation are discussed.