Purcell Effect of Plasmonic Surface Lattice Resonances and Its Influence on Energy Transfer

Engineering the density of photonic states with electromagnetic modes has become an attractive approach for controlling energy transfer between molecular systems. Here we report the use of surface lattice resonances (SLRs) that arise in arrays of metal-insulator-metal (MIM) nanocylinders to control the energy transfer between two archetypal molecular dyes, P580 ( donor) and P650 (acceptor). When the SLR is detuned from the donor emission, energy transfer is observed as expected, with donor emission decreasing with respect to the acceptor emission (donor/ acceptor peak fluorescence ratio = 0.45). In contrast, when the SLR is tuned to the donor emission, Purcell enhancement becomes dominant, outcompeting energy transfer and suppressing acceptor emission (donor/acceptor peak fluorescence ratio = similar to 5.4). To analyze these observations, a kinetic model was developed, based on pumping rate, donor-to-acceptor energy transfer rate, and radiative and nonradiative decay of the dyes. The results suggest the additional decay channel introduced by the SLR for which lambda(SLR)(k parallel to)= 0 = lambda(donor)(emission) competes strongly with the energy transfer process, while SLRs that coincide with donor emission peaks at larger values of in-plane momentum k(parallel to) have a less pronounced effect. Our study highlights the wide range of SLR-based Purcell effects possible by simple changes in the lattice dimensions and their consequences in the kinetics of molecular energy transfer processes in the condensed phase.