Plasmon-induced enhancement of intra-ensemble FRET in quantum dots on wrinkled thin films

We demonstrate increased intra-ensemble energy transfer (ET) in monodispersed semiconducting quantum dots (QDs), mediated by localized plasmons on metallic thin films with nano-scale wrinkles. The increased ET results in a net spectral red-shift, up to three-fold increase in emission intensity, and a faster radiative recombination rate of the ensemble. The extent of the red-shift is dependent on QD size, and is largest for the QDs where the absorption spectrum overlaps the plasmonic resonance of the film. This effect has a uniform, macroscopic manifestation and may provide an inexpensive option of improving performance of QD based photovoltaic devices.