Hollow microscale organization of Bi2S3 nanorods

This paper describes a polyethylene glycol (PEG)-assisted approach to the large-scale hollow organization of bismuth sulfide nanorods, formed by a hydrothermal reaction between Bi-PEG complexes and thiourea. Field-emission scanning electron microscopy studies indicate that these microspheric assemblies have a hollow central cavity. The constituent Bi2S3 nanorods possess a diameter of tens of nanometres with lengths of similar to 1.5 mu m. High-resolution transmission electron microscopy and selective-area electron diffraction studies reveal that each Bi2S3 nanorod is a single crystal along the < 001 > direction. The mechanism for the hollow organization is proposed. The bismuth species added to the PEG solution convert the PEG polymer coils to Bi(III)-PEG globules and the initial transparent solution of Bi(III)-PEG globules turns to pale yellow Bi-III(Tu)(x)/PEG when thiourea is added. The decomposition of Bi-III(Tu)(x)/PEG and the deposition of Bi2S3 on the flexible structures of the globules, which are the templates for the growth of Bi2S3 nanorods, results in the observed structure of interest. The Bi2S3 nanorods grow via the very tiny units of bismuth sulfide attaching to the template during the hydrothermal process.