Morphogenesis and crystallization of Bi2S3 nanostructures by an ionic liquid-assisted templating route:: Synthesis, formation mechanism, and properties

An ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) solution system has been designed for the morphogenesis and crystallization of Bi2S3 nanostructures at low temperature and ambient atmosphere. Uniform Bi2S3 flowers with a size of 3-5,mu m, which are composed of nanowires with a diameter of 60-80 nm, can be prepared in large scale by the template effect of the ionic liquid solution, in which vesicles are formed as confirmed by laser light scattering (LLS) analysis. The formation mechanism of the flowers has been proposed. With prolonged aging time, the flowerlike structures tend to become loose and fall off from the mother flowers, and finally the individual nanowires will form. The results demonstrated that the shape evolution and phase transformation strongly depend on the reaction conditions, such as pH value, reaction temperature, and reaction time. This reaction system could be extended for the morphogenesis of other inorganic nanomaterials with novel morphology and complex form.