The fact that fullerenes are good electron acceptors has generated interest in covalently linked complexes between
electron donors and fullerenes; photoinduced charge transfer in these dyads has great potential for use in photovoltaic
devices. In this Letter, we investigate the excited-state properties of a perylene–fulleropyrrolidine dyad using steady-state
and femtosecond time-resolved spectroscopies. Following photoexcitation, charge separation and energy transfer occur in
nearly equal proportion; both processes take place on a sub-picosecond timescale. This suggests that competition between
energy and charge transfer is common in these molecular systems, so that the best molecules for device applications are not
necessarily those with the fastest electron transfer rates
