Synthesis of colloidal PbSe/PbS core-shell nanowires and PbS/Au nanowire-nanocrystal heterostructures

The oriented attachment of PbSe nanocrystals results in single-crystal line colloidal PbSe nanowires. The addition of different surfactants allows tailoring nanowire morphology, choosing between straight, zigzag, helical, and branched nanowires. In this work, we studied the formation of coaxial PbSe/PbS core-shell heterostructures and observed Stranski-Krastanov growth regime of PbS shell on PbSe nanowires at low reaction temperature (150 degrees C) that switched to layer-by-layer epitaxial growth above 180 degrees C. The protection of PbSe nanowires with a PbS shell substantially improves the nanowire stability against oxidation. We also developed a technique for controllable decoration of colloidal PbSe nanowires with Au nanoparticles and found that the morphology of nanowire template had a strong effect on nucleation and growth of gold nanoparticles.