Preparation of chiral quantum dots.

Abstract

Chiral quantum dots (QDs) are expected to have a range of potential applications in photocatalysis, as specific antibacterial and cytotoxic drug-delivery agents, in assays, as sensors in asymmetric synthesis and enantioseparation, and as fluorescent chiral nanoprobes in biomedical and analytical technologies. In this protocol, we present procedures for the synthesis of chiral optically active QD nanostructures and their quality control using spectroscopic studies and transmission electron microscopy imaging. We closely examine various synthetic routes for the preparation of chiral CdS, CdSe, CdTe and doped ZnS QDs, as well as of chiral CdS nanotetrapods. Most of these nanomaterials can be produced by a very fast (70 s) microwave-induced heating of the corresponding precursors in the presence of D- or L-chiral stabilizing coating ligands (stabilizers), which are crucial to generating optically active chiral QDs. Alternatively, chiral QDs can also be produced via the conventional hot injection technique, followed by a phase transfer in the presence of an appropriate chiral stabilizer. We demonstrate that the properties, structure and behavior of chiral QD nanostructures, as determined by various spectroscopic techniques, strongly depend on chiral stabilizers and that the chiral effects induced by them can be controlled via synthetic procedures.