Determining Fluorescence Quantum Yield of C60 in Toluene
Toluene instead of benzene can be a poor choice when H-atom abstraction by the excited state is possible. Here, you're safe.

Try to get a copy of Fluorescence spectra and quantum yields of buckminsterfullerene (C60) in room-temperature solutions. No excitation wavelength dependence.

The authors apparently used 9-cyanoanthracene in toluene as a standard to determine $\Phi_f$ of C60.

You might also want to have a look for review articles by Dirk Guldi from the time around 2000; I remember him giving a number of talks on C60 around that time.