Enhancing the thermoelectric performance of SnSe by the introduction of Au nano dots

Abstract

The electrical and thermal properties of thermoelectric performance can be decoupled by devising low-dimensional metal-semiconductor nanotechnology, which results to higher thermoelectric performance. In this work, 0D–2D (0 Dimension-2 Dimension) Au-SnSe nanocomposites with intensive interface barriers and beneficial phonon scattering were designed. Au NDs (nano dots) distributed on the surface of SnSe nanoplates, thereby forming the 0D–2D Au-SnSe nanocomposites. The Au NDs with abundant electrons were introduced to improve the electrical transportation properties while the 0D–2D nanostructure grain interfaces were designed to reduce phonons transportation property in comparison with the pure SnSe matrix. The interface barriers between Au NDs and SnSe nanoplates can effectively filter low energy holes and scatter mid and long wavelength phonons. As a consequence, the electrical conductivity of 1 mol% Au/SnSe nanocomposite is 2211.1 Sm−1 at 773 K, increasing by 174.2% with respect of that of pure SnSe, and, meanwhile, the thermal conductivity is 0.363 Wm−1 K−1, reducing by 11.2%. Attributed to the large enhancement in electrical transport and the diminution in thermal conductivity, a much higher ZT value of 0.6 is obtained for 1 mol% Au/SnSe nanocomposite at 773 K, which is in good contrast to 0.16 for pure SnSe nanoplates.