Optical Properties of Monodisperse ZnSe:Mn/ZnS Core–Shell Nanocrystals Synthesized via an Alkylthiol-Assisted Phosphine-Free Method

ZnSe:Mn/ZnS core–shell nanocrytals were successfully synthesized via a nucleation-doping strategy assisted with a low-toxicity, high-reactivity, and organic soluble selenium precursor in oleyamine. The as-prepared ZnSe:Mn/ZnS nanocrytals were then investigated by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), ultraviolet-visible (UV-Vis) absorption spectroscopy, and photoluminescence (PL) spectroscopy. All the results showed that the ZnSe:Mn/ZnS nanocrystals have good monodispersibility and high photoluminescence. Further systematic research found that injection temperature of 250 °C, three ZnS layers, and Mn doping concentration of 2% are the optimal parameters for the synthesis of high luminescence ZnSe:Mn/ZnS nanocrystals. Additionally, these ZnSe:Mn nanocrystals exhibit temperature- and magnetic field-dependent optical properties, which show great potential in the application of temperature and magnetic field sensing.