Facile Synthesis of Highly Luminescent Water-Soluble ZnSe:Mn/ZnS Core/Shell Doped Nanocrystals with Pure Dopant Emission

A new two-step method is reported to synthesize water-soluble ZnSe:Mn/ZnS core/shell doped quantum dots (d-dots) with pure dopant emission, high photoluminescence (PL) efficiency, and excellent stablility. The optical properties and structure of the obtained ZnSe:Mn/ZnS core/shell d-dots were characterized by UV-vis spectroscopy, PL spectra, X-ray diffraction (XRD) and transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) in detail. The influences of experimental variables, including the ZnS shell thickness and the Mn doped concentration on the optical properties of the ZnSe:Mn/ZnS d-dots, have been systematically investigated. Finally, the stability against UV irradiation and chemical oxidation of these highly luminescent d-dots were studied, and the results showed that the ZnSe:Mn/ZnS core/shell d-dots were photostable under the intense UV irradiation for 5 h, and possessed better chemical stability than CdSe q-dots, showing their potential applications in biological labeling and light emitting devices.