On Carbon “Replacing” the Core in Classical Semiconductor Core/ZnS Quantum Dots

Among best known semiconductor quantum dots (QDs) are CdSe/ZnS core/shell nanostructures, whose much enhanced photoexcited state properties over those of uncapped CdSe nanoparticles are rationalized in the literature such that "the ZnS capping with a higher bandgap than CdSe passivates the core crystallite removing the surface traps".In this work, the method commonly employed in the ZnS capping of CdSe for CdSe/ZnS QDs was applied to the same capping of small carbon nanoparticles (CNPs) for CNP/ZnS core/shell nanostructures, which are conceptually and configuration-wise equivalent to the replacement of the semiconductor (CdSe) core with CNP in the classical core/shell QDs.The fluorescence emission properties of CNP/ZnS core/shell nanostructures were found to be similar to those of organic functionalized CNPs in classically defined carbon dots (CDots), both dramatically enhanced from those of "naked" CNPs in solvent dispersions.Mechanistic implications of the findings are discussed.