Comparative Studies of Blue-Emitting Zinc Selenide Nanocrystals Doped with Ag, Cu, and Mg towards Medical Applications

Blue-emitting Ag(+)-, Cu(2+)-, and Mg(2+)-doped ZnSe nanoparticles (NPs) were successfully synthesized at 80 degrees C by the precipitation method by using mercaptopropionic acid (MPA) as a stabilizer. UV-visible and photoluminescence (PL) studies were applied to investigate their physicochemical properties. Their structural properties were confirmed by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and transmission electron microscopy (TEM). The size of the ZnSe: X-capped MPA showed a strong relationship with dopant metals. The diameters of the Mg-doped ZnSe and the Cu-doped ZnSe were 22-24 nm, while the Ag-doped ZnSe was halved, at about 13 nm. The photoluminescence was within a wavelength range of 400-550 nm. In addition, the PL intensities, as well as the photoluminescence quantum yields, were in the order of the decreasing ionic radii of the dopant metals (ZnSe:Ag < ZnSe:Mg < ZnSe:Cu). Furthermore, through the interaction with lysine, the PL intensity of the ZnSe:X was changed. Interestingly, the capacity of the ZnSe:Mg for lysine was significantly higher than that of other dopant metals. Moreover, the toxicity of the ZnSe:Mg was relatively insignificant toward the hMSCs (about 80% cell viability at 320 ppm), compared to the transition-metal dopant. Therefore, the ZnSe:Mg material could have great potential for bioapplications.