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

Absorption and emission properties of [60]fullerene and [70] fullerene in solutions of ten different solvents were studied, With the use of anear-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 x 10(-4) and 5.7 x 10(-4), respectively, and the yields are slightly different in other solvents. For most applications, the fluorescence quantum yield ratio Phi(F,C70)/Phi(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.