Hierarchical, star-shaped PbS crystals formed by a simple solution route

Hierarchical eight-arm, star-shaped PbS single crystals have been successfully synthesized by the controlled release of sulfide ions from thioacetamide (TAA) at 80 degreesC in aqueous solutions of lead acetate and acetic acid. The unique star-shaped PbS crystals have eight symmetric arms along the <111> directions, each of which shows a trident-like, dendritic structure and consists of parallel PbS nanoleaflets. It has been revealed that the presence of acetate ions as well as appropriate pH and temperature are crucial for the formation of the unusual star-shaped PbS crystals. Moreover, other morphologies of PbS nanocrystals, such as nanorods, nanostrips, and nanosheets, have been obtained facilely at 40 degreesC by using similar synthetic procedures.