Synthesis and surface modification of PbSe/PbS core-shell nanocrystals for potential device applications

We report in this paper the growth of PbS shells over colloidal PbSe nanocrystal quantum dots (NQDs) with monolayer-precision. The technique of successive ion layer adsorption and reaction (SILAR) has been adapted to the growth of high-quality core-shell nanocrystals. The core-shell infrared NQDs were ligand-exchanged with short-chain octylamine, and the photoluminescence efficiency of the surface-engineered core-shell nanoparticles was substantially higher than that of the plain core structures undergoing the same surface processing, which reveals less ligand dependence and enhanced chemical robustness in the core-shell NQDs. The reported results open up the possibility of incorporating semiconductor infrared NQDs in the silicon matrix to develop all-inorganic light-emitting heterojunctions on silicon substrates.