Resonance energy transfer from a fluorescent dye to a metal nanoparticle

Abstract

A quantum mechanical theory of the rate of excitation energy transfer from a fluorescent dye molecule to the surface plasmonic modes of a spherical metal nanoparticle is presented. The theory predicts the distance dependence of the transfer rate to vary as 1/d^σ, with σ = 3-4 at intermediate distances, in partial agreement with the recent experimental results. Forster's 1/d⁶; dependence is recovered at large separations. The predicted rate exhibits nontrivial nanoparticle size dependence, ultimately going over to an asymptotic, a³ size dependence. Unlike in conventional fluorescence resonance energy transfer, the orientational factor is found to vary between 1 and 4.