Template-free electrochemical deposition of tellurium nanowires with eutectic solvents

Electrochemical deposition of tellurium from deep eutectic solvents (DES) at gold film electrodes produced films of tellurium nanowires. The deposition was evenly distributed over the gold surface, with an average diameter of ∼70 nm and length of ∼1 µm. Deposition was extremely sensitive to the applied potential, tellurium concentration and deposition bath temperature, with deviations away from optimised conditions preventing the formation of the desired nanostructure. Interestingly, replacing the chloride in a popular eutectic solvent with bromide or iodide had a significant impact on the resultant film structure, with bromide giving no clearly defined nanostructure but iodide giving nanoplatelets. This demonstrates a strong control of tellurium nanostructure by halide ions, offering a way to two distinct nanostructures from the same core experimental set up.