Low-temperature synthesis of hexagonal transition metal ion doped ZnS nanoparticles by a simple colloidal method

A general route to synthesize transition metal ions doped ZnS nanoparticles with hexagonal phase by means of a conventional reverse micelle at a low temperature is developed. The synthesis involves N,N-dimethylformamide, Zn(AC)2 solution, thiourea, ammonia, mercaptoacetic acid, as oil phase, water phase, sulfide source, pH regulator, and surfactant, respectively. Thiourea, ammonia and mercaptoacetic acid are demonstrated crucial factors, whose effects have been studied in detail. In addition, the FT-IR spectra suggest that mercaptoacetic acid may form complex chelates with Zn2+ in the preparation. In the case of Cu2+ as a doped ion, hexagonal ZnS:Cu2+ nanoparticles were synthesized at 95 °C for the first time. The X-ray diffraction (XRD) and transmission electron microscope (TEM) measurements show that the ZnS:Cu2+ nanoparticles are polycrystalline and possess uniform particle size. The possible formation mechanism of the hexagonal doped ZnS is discussed.