Significantly enhanced power factor for superior thermoelectric conversion efficiency in SnTe by doping elemental Indium

Abstract

Search for high-performance thermoelectric materials are attractive in directly conversion between heat and useful powers for relieving the energy crisis nowadays. SnTe alloy is always expected to be one ecofriendly candidate, however, its low conversion efficiency has severely limited the practical application as thermoelectric devices, mainly due to the intrinsic low power factor. Here we show that siginificantly enhanced power factors can be achieved in nano-polycrystalline SnTe doped with a small amount elemental Indium (In). Our results demonstrate that the fabricated SnTe in this work shows simultaneously enhanced Seebeck coefficient and decreased carrier concentration with the increase of In content up to 1.25 at%, leading to remarkably improvement of power factors by 95% at 300 K and 56% at 710 K for In0.01Sn0.99Te. Meanwhile, the introduced abundant grain boundaries, dislocations, and lattice distortion in the nanostructured SnTe, which are beneficial for the phonon scattering, can effectively reduce the phonon thermal conductivity. As a result, we observe significant improvement of the conversion efficiency for SnTe throughout wide temperature range from 300 to 710 K and the average ZT in In0.0125Sn0.9875Te can reach up to 0.34, the highest value reported in SnTe-based materials, paving a new way for promising high-performance thermoelectrics.