Crystal structure of high-performance thermoelectric materials by high resolution neutron powder diffraction

Abstract

SnSe has currently the highest figure of merit ZT, and is expected to be applied to thermoelectric devices, due to its intrinsic low lattice thermal conductivity. To further lower the lattice thermal conductivity and enhance the thermoelectric performance, we substituted the Sn and Se by Na and S, respectively. Structural changes by these substitutions were studied by high-resolution neutron powder diffraction experiments: the decreasing of the lattice constants and consequently the distortion of the Sn-polyhedron was observed in Na and S substituted SnSe.