Controlled synthesis of bionic microstructure PbS crystals by mixed cationic/anionic surfactants

Hexagonal starfish-like PbS crystals have been synthesized by the reaction of lead acetate and thioacetamide (TAA) controlled by mixture of cetyltrimethylammonium bromide/sodium dodecyl sulfate (STAB/SDS) at the molar ratio of 5: 1 through a hydrothermal process at 80°C. It has been found that the hexagonal starfish-like PbS single crystal is in cubic phase, and the six arms of the star extend along the six 〈100〉 directions. By changing reaction conditions, such as the molar ratio of CTAB/SDS, temperature, and reaction time, the amounts of TAA and lead sources, the morphology and structure of the PbS crystals can be controlled. Furthermore, possible formation mechanism was preliminarily illustrated. The room-temperature photoluminescence spectra in solid state of the PbS single crystals obtained after different reaction times were investigated, which demonstrated that the PbS single crystals presented excellent optical properties. This work may open a novel route to the shaped-controllable synthesis of semiconductor crystals with various morphologies.