Effect of Sulfur Precursor on Dimensions of One-dimensional CdS Nanocrystals

One-dimensional CdS nanocrystals have been prepared by solvothermal method using cadmium acetate as a cadmium precursor, elemental sulfur and Na2S, as a sulfur precursor, and ethylenediamine as a solvent at 150◦C for 5 h. The nanocrystals were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-Vis absorption spectroscopy. XRD patterns indicate that both Na2S and elemental sulfur as the sulfur precursor result in CdS nanorods with wurtzite phase (hexagonal structure). SEM and TEM images show that diameter of CdS nanorods can be decreased using Na2S instead of elemental sulfur. For the growth of CdS nanorods, a mechanism has been proposed. Uv-Vis absorption of CdS nanorods (sulfur precursor: Na2S) was shown blue shift to 485 nm due to the quantum size effect.