Large energy transfer distance to a plane of gold nanoparticles

The quenching of emission in proximity to metallic surfaces via non-radiative energy transfer is studied for sensing applications. It can also be used for the measurement of distances on the nanoscale. We report on energy transfer from a plane of CdTe quantum dots (QDs) plane to a plane of gold (Au) nanoparticles. Both photoluminescence (PL) and luminescence lifetime measurements demonstrate that energy transfer efficiency not only depends on plane separation but also Au nanoparticle concentration. Energy transfer to the plane of metal nanoparticles can be considered within the standard Förster resonant energy transfer (FRET) model or the nano-metal surface energy transfer (NSET) model. It is found that both dependences are well described within the model of FRET which shows a 1/d⁴ distance dependence and a 1/C_Au Au concentration dependence. However, surprisingly large Förster radii of 10 nm, larger than expected from the spectral overlap of the QD emission and gold localised surface plasmon absorption, are obtained.