Preparation and Shape-Control of Bi₂S₃ Nanocrystals

Stable Bi₂S₃ colloidal nanocrystals with sphere or rod shape were synthesized through a "hot injection" method using organic molecules and macromolecules as ligands. The morphology of Bi₂S₃ nanocrystals is highly dependent on the experimental parameters, including the reaction temperature, reaction time, reactant ratio and ligands. Especially, adjusting the properties of ligands can lead to an obvious shape evolution of Bi₂S₃ nanocrystals. When polyvinylpyrrolidone is added as ligands before the reaction, a stable nanodot colloid is formed. While using polyvinylpyrrolidone and thioglycolic acid as mixed ligands benefits for the formation of Bi₂S₃ nanorods. The synthesized Bi₂S₃ nanorods were used as seeds in the second-step growing process to achieve a stable, shape and size controlled Bi₂S₃ nanocrystals. The Bi₂S₃ nanocrystals were characterized by XRD, UV-Vis and TEM.