Abstract

The possibility to grow thick CdS shells on CdSe core nanocrystals with variable thicknesses offers a way to control the emission of nanocrystals. First of all it is possible to get very low flickering fluorescence. Single photon sources or multiexcitonic emitters can be obtained by controlling Auger processes that depend on the shell thickness. This emission can also be controlled by coupling the nanocrystal to plasmonic structures. In this case the shell acts as a spacer, preventing quenching of the fluorescence. We have previously shown that CdSe/CdS QDs fluorescence can be dramatically modified by semi continuous gold films at the percolation threshold presenting hot spots [1]. The decay rate enhancement, corresponding to the Purcell factor can reach values as high as 200. Moreover the residual flickering of the emitter is completely suppressed and far field emission collection can be improved.

© 2015 IEEE