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.