Résumé
Semiconductor quantum dots (QDs) are luminescent nanocrystals offering bright and narrow emissions from UV to near-infrared. As a result, they find numerous applications as light emitters in a wide range of technologies, from photonics to biotechnologies. Among these materials, heterostructures such as core-shell QDs are of particular interest. Indeed, capping QDs with a larger band gap material results in a better confinement of the exciton in the core, hence improving the photoluminescence quantum yield (PLQY) and decreasing the blinking behavior of the QDs. We recently developed a new very fast method for the synthesis of such CdSe/CdS core-shell QDs. Thanks to the high quality of the nanocrystals produced with this technique, their potential application as luminescent nanoprobes for biotechnologies could be investigated. The QDs were rendered water soluble and biocompatible by their encapsulation in silica nanoparticles (NPs) through a water-in-oil microemulsion process. The synthesized CdSe/CdS@SiO2 NPs fully retained their PLQY even after several months in water, whereas similar NPs based on QDs synthesized by a SILAR procedure typically lose their luminescence after few days in water. The potential application of these CdSe/CdS@SiO2 NPs will also be presented with the fluorescent labeling of living cell.