Role of Nd 3+ ions on the nucleation and growth of PbS quantum dots ( QD s) in silicate glasses

The influence of Nd 2 O 3 addition on the precipitation kinetics of lead chalcogenide (PbS) quantum dots ( QD s) in silicate glasses was investigated. Energy dispersive X‐ray spectroscopy ( EDS ) indicated that the Nd 3+ ions are preferentially located inside the PbS QD s rather than in the glass matrix. Changes in diameter ( D ) of PbS QD s exhibited smaller time dependencies (i.e., D ≈ t 0.270‐0.286 ) than that predicted by the classical Lifshitz–Slyozov–Wagner ( LSW ) theory. This is due to the limited concentrations of Pb 2+ and S 2− 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 QD s was retarded due to the presence of Nd 2 O 3 in the glasses, as the large NdO x polyhedra interrupt the diffusion of Pb 2+ and S 2− ions. We believe that these Nd 3+ ions are primarily located in PbS QD s in the form of Nd–O clusters, and that the PbS QD s are built on top of these clusters.