High-pressure study of picosecond exciton dynamics in solid C60

We have studied the singlet exciton decay by picosecond photoinduced absorption in films of Qo, under pressures up to 62 kbar. The picosecond decay of excitons excited in the absorption tail continues to be dominated by broad distributions of lifetimes at high pressure. These results suggest that the distributions of lifetimes do not arise from variations in tunneling or hopping rates between molecules as was originally suggested, but arise from distributions of recombination rates at different sites in the sample.