Size control, shape evolution, and silica coating of near-infrared-emitting PbSe quantum dots

The physical and optical properties of quantum dots (QDs) are governed by their particle size and shape. In this study, near-infrared-emitting PbSe QDs were synthesized with controlled size (between 7 and 12 nm) and shape (spheres, octahedrons/cubes), with tunable emission from 1200 to 1500 nm. The hydrophobic PbSe QDs were coated with a silica shell to render them water-soluble and non-cytotoxic. The cell viability of NIH-3T3 (mouse fibroblast cells) and HepG2 (human liver cancer cells) was retained at 80% even in the presence of a high QD loading of 100 mu g/mL.