Synthesis and characterization of ZnS nanocrystals doped with Cd²⁺ and Mn²⁺ based on the macromonomer ligands

In this paper, we reported the successful synthesis of Cd²⁺ or Mn²⁺ doped ZnS composite nanocrystals, which employed zinc acetate, cadmium chloride, manganese acetate and sodium sulfide as raw materials, along with poly (methacrylic acid) (PMAA) macromonomer containing unsaturated vinyl end groups as the stabilizing agent. The as-prepared composite nanocrystals with good fluorescent properties were well dispersed in aqueous solutions without any aggregation. The detailed structure and optical properties of these nanocrystals were investigated by conductivity analysis, TGA, UV-Vis and photoluminescence spectra (PL) measurements. The experimental observations suggest that the formation of coordination bond between nanocrystals and the carboxyl groups of PMAA macromonomer occurs in this case. It is also noted that we could fabricate a series of optical ZnS:Cd²⁺ composite nanocrystals ranged from ultraviolet region to visible light region by varying the amount of doped Cd²⁺ in these composite nanocrystals.