Role of Nd3+ ions on the nucleation and growth of PbS quantum dots (QDs) in silicate glasses

Abstract

The influence of Nd2O3 addition on the precipitation kinetics of lead chalcogenide (PbS) quantum dots (QDs) in silicate glasses was investigated. Energy dispersive X-ray spectroscopy (EDS) indicated that the Nd3+ ions are preferentially located inside the PbS QDs rather than in the glass matrix. Changes in diameter (D) of PbS QDs exhibited smaller time dependencies (i.e., D?t0.270-0.286) than that predicted by the classical Lifshitz?Slyozov?Wagner (LSW) theory. This is due to the limited concentrations of Pb2+ and S2? ions and the large diffusion distance inside the glass matrix. In addition, extended X-ray absorption fine structure (EXAFS) results indicated that the formation of PbS QDs was retarded due to the presence of Nd2O3 in the glasses, as the large NdOx polyhedra interrupt the diffusion of Pb2+ and S2? ions. We believe that these Nd3+ ions are primarily located in PbS QDs in the form of Nd?O clusters, and that the PbS QDs are built on top of these clusters. ? 2017 The American Ceramic Society