Synthesis of ZnS:Ni nanocrystals (NCs) using a thermochemical approach and investigation of the photoluminescence properties

In this work we have synthesized doped ZnS:Ni nanocrystals (NCs) using a new thermochemical method. Zn(NO3)2 and Na2S2O3 were used as the precursors and Ni(NO3)2 was the source of impurity. Thioglycerol (TG) was used as the capping agent and the catalyst of the reaction. Na2S2O3 is a heat sensitive material which releases S species upon heating. The reaction was done in two steps. In the first step, the precursors were heated at 96 °C for an hour without TG and then TG was injected to the solution and the heating process was continued for longer heating durations. The structure and optical property of the NCs were characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), UV–visible optical spectroscopy and photoluminescence. XRD and TEM analyses demonstrated cubic phase ZnS:Ni NCs with an average size around 3 nm. Synthesized NCs exhibited band gap of about 4.1 eV. The photoluminescence spectra showed a blue–green emission centered at 490 nm, demonstrating the Ni incorporation in the ZnS NCs structure.