A close look at the Förster energy transfer in the vicinity of a metallic nanoparticle

Abstract

The energy of an excited molecule (donor) can be transferred to a nearby molecule (acceptor) in ground state (Förster energy transfer). This mechanism, due to intermolecular electromagnetic interaction, depends on the environment in which the donor-acceptor pair is embedded. We closely examine the influence of a gold nanosphere on the Förster energy transfer rate K_F including the impact of excitation of surface plasmons. When the intermolecular distance R is 3 nm, the influence by the metallic nanosphere on K_F is weak. However, when the donor-surface separation is a few nanometers from the surface and R is 3 nm, K_F is modified by the presence of the nanoparticle. The excitation of surface plasmons causes a stronger perturbation of K_F. In the aforementioned region (R3nm), KF can be enhanced with respect to K_F0 (Förster energy transfer rate without nano-sphere).