Fabrication of freestanding tellurium nanofilm and its thermoelectric performance

Low-dimensional tellurium-based nanowires (NWs) have gained much attention as ideal thermoelectric materials. The preparation of high quality NWs remains a challenge in the field of nanotechnology. Owing to the superior performance, tellurium (Te) NWs are attractive materials for many applications. In this work, the Te NWs were synthesized by a hydrothermal route. We acquired the ultra-fine Te NWs through optimization, and the diameter is 10-35 nm. The optimized Te nanofilm was freestanding and the Te/polyvinylidene fluoride film can be rolled up by a pencil which showed the flexibility of the membrane. The as-prepared Te NWs films have been investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy. Although the ultra-fine Te NWs film shows the acceptable electrical conductivity, its Seebeck coefficient is as high as 551 μV K−1 and the thermal conductivity is as low as 0.16 W m−1 K−1. To achieve a higher thermoelectric performance, the effort will be devoted into the improvement of electrical conductivity in next work.