Blinking suppression and biexcitonic emission in thick-shell CdSe/CdS nanocrystals at cryogenic temperature

It is well-known that, at the single molecule level, the fluorescence emission of semi-conductor nanocrystals (NCs) fluctuate in intensity. For regular NCs, these fluctuations are between “on and off” states, due to the existence of a complete dark state. This corresponds to the blinking phenomenon. This blinking has been associated to the very efficient Auger recombination processes. Recently, CdSe/CdS NCs with a thick (more than 5 nm) shell have been synthesized and studied [1]. The Auger lifetimes of these NCs have been measured in the range of tens of nanoseconds. The efficiency of Auger recombination and the possibility to completely suppress these processes are actively investigated, for lasing applications for example.