Insights into the local atomic structure of nanostructured SnSe thermoelectric material

Excellent thermoelectric properties were reported in undoped p-type SnSe single crystals. SnSe shows elevated Seebeck of 668 μVK-1 near RT, low thermal conductivity of 0.1 Wm-1K-1, and zT > 2. Even better performance was predicted in n-type SnSe. In our recent works, SnSe were prepared by arc-melting as robust pellets, presenting textured nanostructures. Doping elements were stabilized, as the case of Ge and Sb within the SnSe lattice. Good thermoelectric performance was reached, exhibiting zT near 2 for polycrystalline samples, which is very close to that for single-crystals. We propose to address both p- to n-type and Pmna to Cmcm transitions in SnSe thermoelectrics, by performing X-ray absorption measurements at Sn and Se K-edges on polycrystalline tin selenide from 300 up to 1000 K, under vacuum, on beamline BM23 at ESRF. The beamline in its standard mode is equipped with a high-temperature furnace and full capabilities to perform high-quality XANES and EXAFS spectra.