Synthesis of Te-Bi core-shell nanowires by two-step electrodeposition in ionic liquids

Te-Bi core-shell nanowires were synthesized by electrochemical deposition in ionic liquids without using a template. The nanowires were synthesized in two steps: self-standing single crystal Te nanowires with a diameter of 76.2 ± 28.4 nm and a length of a few microns were electrodeposited first, taking advantage of the templating properties of the mixture of ionic liquids EOPipTFSI:EOPipBr 95:5 mole%. The Bi shell was then deposited on the Te core in EOPipTFSI. The influence of various experimental parameters on Bi shell deposition was studied. Thanks to the higher viscosity of the electrolyte compared to an aqueous medium, a lower growth rate is observed, leading to a thin layer of bismuth. In addition, High Resolution Transmission Electronic Microscopy shows that under optimal conditions the Te nanowires are entirely covered by a homogeneous, compact and polycrystalline Bi shell and that the core/shell interface is smooth.