Nano- and Molecular-Solder Introduced Thermoelectric Materials

Abstract

Highly efficient thermoelectric materials have attracted tremendous attention due to various technological applications such as power generation from waste heat and environmentally friendly refrigeration. Recently, nanostructuring has become the core of thermoelectric (TE) material research because it creates numerous internal interfaces that provide an effective way to tune the thermal and/or electrical properties. Herein, we propose a new strategy for interface engineering of nanostructured TE materials by introducing chemically synthesized nanostructures or molecular compounds as solders. These solders easily fill up the voids and interfaces between TE particles and form crystalline phases to interconnect TE particles upon heat treatment with no external pressure, which led to huge densification and substantial growth of TE grains. The chemical design of solders allowed for the selective enhancement or reduction of the majority carrier concentration near the grain boundaries, and thus resulted in doped or de-doped inter-faces in granular BiSbTe material. Furthermore, the energy filtering effect could be realized by the formation of potential well at interfaces. Finally, the low temperature sintering properties enabled us to design shapes and dimensions of TE materials and devices with high performance via a facile and cost-effective TE painting process using a brush directly on to any-shaped surfaces.