Highly Emissive, Color-Tunable, Phosphine-Free Mn:ZnSe/ZnS Core/Shell and Mn:ZnSeS Shell-Alloyed Doped Nanocrystals

High-quality Mn:ZnSe/ZnS core/shell and Mn:ZnSeS shell-alloyed doped nanocrystals (d-dots) with up to 50% photoluminescence (PL) quantum yield (QY) have been synthesized based on nucleation-doping strategy through a phosphine-free approach. The formation of MnSe nanoclusters was achieved by adjusting the ratio of stearic acid to manganese stearate and using a highly reactive Se precursor. Mn: ZnSe/ZnS core/shell d-dots were prepared by an epitaxial ZnS growth on the Mn:ZnSe core. The PL QY of Mn:ZnSe/ZnS core/shell d-dots decreased dramatically after injections of S precursor but was completely recovered through an UV irradiation. After annealing at 240 °C for 30 min, the core/shell Mn:ZnSe/ZnS d-dots evolved to the Mn:ZnSeS shell-alloyed d-dots with high PL QY. The PL peak position of the d-dots could be tuned within a relatively large optical window, from 584 to 605 nm.