  We demonstrate that longitudinal plasmons in doped monolayer graphene can
mediate highly efficient long-range energy transfer between nearby
fluorophores, e.g., semiconductor quantum dots. We derive a simple analytical
expression for the energy transfer efficiency that incorporates all the
essential processes involved. We perform numerical calculations of the transfer
efficiency for a pair of PbSe quantum dots near graphene for inter-fluorophore
distances of up to 1 $\mu$m and find that the plasmon-assisted long-range
energy transfer can be enhanced by up to a factor of $\sim10^4$ relative to the
F\"{o}rster's transfer in vacuum.
