Control of the morphology and size of PbS nanowires using gold nanoparticles

Anisotropic growth of nanocrystalline PbS with a variety of morphologies was achieved via hot colloidal synthesis in the presence of Au nanoparticles. Synthesis using Au nanoparticles produced more uniform diameter nanowires than could be obtained in their absence. A variety of other morphologies, such as nanorods, nanocubes, nanocauliflowers, and core-shell particles, were also obtained by varying the molar ratios of the precursor ions. The effect of Au seed particles appears to result from their ability to provide nucleation sites to seed anisotropic growth of the semiconductor nanocrystals. The method demonstrated here provides a facile hot colloidal method of producing high-quality high-aspect-ratio PbS nanowires of controlled diameter in high yield. The ability of these nanowires to provide infrared photosensitization in a polymeric photoconductive device is demonstrated.