Dynamical behavior of photoluminescence of fullerene C60

Using a picosecond excitation source and a time-resolved streak camera detection system, we have observed the time-resolved photoluminescence spectra of C60 from toluene solution at room temperature and from thin film at both room temperature and 77 K. For C60 solution, a photoluminescence peak at about 730 nm was detected at room temperature and its decay time was determined to be 1.1 ns. For C60 film, the photoluminescence peak was at about 730 nm at 77 K and 740 nm at room temperature, respectively. Its time decay behavior changed from a slow process with decay time of 0.9 ns to a fast process which was fitted well to a double exponential of decay times of (tau) 1 equals 0.087 ns, (tau) 2 equals 0.68 ns. Some relaxation mechanisms are suggested in explaining this phenomenon.