Controllable synthesis of Bi2S3 hierarchical nanostructures: Effect of addition method on structures

Bi2S3 microcrystallites with three-dimensional (3D) superstructures were synthesized by the reaction of bismuth nitrate (Bi(NO3)(3)) with sodium O-isopropyldithiocarbonate (isopropyl xanthate, C3H7OCS2Na) at 80 degrees C in N,N-dimethylformamide (DMF) solution without any surfactants. It was observed that Bi2S3 crystalline nanorods aggregated to urchin-like globules in the microscale when C3H7OCS2Na was slowly added to Bi(NO3)(3) in DMF solution at 80 degrees C, while cockscomb-like microspheres aggregated by Bi2S3 nanobelts with a typical width of similar to 20 nm were obtained if two precursors were mixed at room temperature and then heated to 80 degrees C. Possible mechanisms for the formation of 3D Bi2S3 microcrystals were proposed. The structures of Bi2S3 crystals were examined by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and laser Raman spectroscopy. (C) 2009 Elsevier B.V. All rights reserved.