Enhanced Thermoelectric Performance of SnSe with Trace Au Particles via Transport Channel Design

Thermoelectric (TE) materials attract worldwide attention due to their energy conversion advantage from its stability and no moving parts. Au/SnSe composites are designed and prepared by using vacuum melting, grinding, physical vapor deposition, and spark plasma sintering. Anisotropic microstructure is confirmed by XRD patterns and SEM images. Introduction of Au changes the transport channel of carriers along press direction due to the percolation effect, which results in the increase of electrical conductivity along this direction. A reverse barrier is also constructed on the metal-semiconductor (Au/SnSe) interface to successfully filter the low energy carriers, contributing to the enhanced Seebeck coefficient. Together with the filter effect and the increased phonon scattering by the heterogeneous interface, a maximum ZT value similar to 0.72 is achieved in Au/SnSe composite with 5 s deposition time along the press direction. This study opens new prospects for optimizing the anisotropic TE materials.