The effect of the silica thickness on the enhanced emission in single particle quantum dots coated with gold nanoparticles

The fabrication of highly luminescent, chemically stable and biocompatible small optical probes is of key interest in bioimaging. Herein we develop a multistep synthesis of hybrid superstructures that comprise quantum dot cores and dense layers of gold nanoparticles separated by a silica shell. This architecture allows for the versatile control of the QD-metal interactions by controlling the thickness of the dielectric spacer. The shell thickness is optimized at the nanometer scale in order to increase the enhanced photoluminescence. Further characterization of the emission in the single particle regime shows that our brighter particles require smaller acquisition times to yield better imaging results.