Fabrication of transition metal sulfides nanocrystallites via an ethylenediamine-assisted route

Many binary transition metal sulfides nanocrystallites MS (M = Zn, Cd, Co, Ni) with different morphologies have been successfully prepared in an ethylenediamine solution of metal salts and (NH4)2S (or thiourea) using a facile hydrothermal method. The products are characterized by powder X-ray electron diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and the selected area electron diffraction (SAED), respectively. UV-visible optical absorption spectra clearly indicate the presence of quantum size effects in some transition metal sulfides nanocrystallites and the possible mechanism of ethylenediamine-assisted is also briefly discussed. This method may also be extended to controllable synthesis of other metal chalcogenides with different morphologies, such as nanowires, nanorods, and nanodisks, etc.