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.