Monodisperse CuInS₂/CdS and CuInZnS₂/CdS Core–Shell Nanorods with a Strong Near-Infrared Emission

Given the ubiquitous examples of semiconductor nanorods synthesis, CuInS₂-based anisotropic heterostructures still lag behind in terms of shape/optical properties control. Here, core/shell CuInS₂/CdS dot-in-rod nanoheterostructures which exhibit high degree of the morphology control, and a strong emission in the near-infrared range of 700–900 nm, are realized. The authors made use of the seeded growth approach utilizing wurtzite CuInS₂ quantum dots as seeds, which allows for tuning the dimension of the resulting core/shell nanorods, including the core size and the shell thickness. Time-dependent photoluminescence studies reveal slowing down of the recombination rate with increasing thickness of the shell, which is characteristic for the quasi-type II heterostructure. Alloying of the CuInS₂ cores with Zn does not perturb the shell growth process, but enables improvement of the photoluminescence quantum yield of the resulting core/shell CuInZnS₂/CdS nanorods to 45%, as compared to ≈30% for CuInS₂/CdS nanorods.