Synthesis and characterization of high-quality colloidal Mn2+-doped ZnS nanoparticles

High-quality colloidal Mn2+-doped ZnS nanoparticles (ZnS:Mn2+ NPs) were synthesized via a facile chemical precipitation method using ethylene glycol (EG) as the capping agent and as the solvent. The phase structure and morphologies of the ZnS:Mn2+ NPs were characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). The results show that as-synthesized ZnS:Mn2+ NPs have a cubic zinc blende structure and are monodispersed. All of the obtained NPs easily dispersed in water to form stable and clear colloids, which have a strong yellow emission under UV excitation. The concentration of Mn2+ and VEG/VH2OVEG/VH2O ratio had a significant effect on the optical properties of the ZnS:Mn2+ NPs . The maximum concentration of Mn2+ and the VEG/VH2OVEG/VH2O ratio had a significant effect on the optical properties of the ZnS:Mn2+ NPs.The maximum photoluminescence (PL) intensity was obtained with 1% of Mn2+ and a higher VEG/VH2OVEG/VH2O ratio reduced the surface defects which enhanced the Mn2+ emission intensity in the ZnS:Mn2+ NPs. The ZnS:Mn2+ NPs were stable in water, even after 30 days. All results indicate that these ZnS:Mn2+ NPs could be promising materials for biolabeling.

► High-quality ZnS:Mn nanoparticles were synthesized via a facile method.
► ZnS:Mn nanoparticles show strong yellow emission under UV excitation.
► The effects of several factors on the emission intensity were researched.
► ZnS:Mn nanoparticles show monodispersed.