Shape-Controlled Solventless Syntheses of Nano Bi Disks and Spheres

Novel nano Bi spheres and hexagonal disks have been synthesized via the thermolysis of a bismuth-thiolate precursor in a mild solventless condition with the help of capping reagents that have shown an isotropic or anisotropic absorption tendency on the Bi crystal faces. Various techniques such as X-ray diffraction, electron dispersive spectroscopy, scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, and atomic force microscopy have been used to characterize the purity, composition, and morphology of the nanoproducts. The experiments also reveal size dependencies based on thermolysis temperature and annealing time of both disks and spheres. In addition, the reactant molar ratio also affects the morphology. Finally, a possible growth mechanism has been proposed, and the as-synthesized disks and spheres have exhibited different UV−vis absorption spectra.