Enhancing the thermoelectric property of Bi2Te3 through a facile design of interfacial phonon scattering

Abstract

From the perspective of green development, the pursuit of more facile and effective method toward improving thermoelectric efficiency of Bismuth Telluride (Bi2Te3) and its alloys has long been attractive. Recent researches indicate that the phonon scattering effect emerging on the nano-grain boundaries or the interfaces in composites can lead to remarkably improved ZT value. Inspired by such methodology to design effective interfacial phonon scattering, we have succeed in fabricating a novel thermoelectric composites based on conducting bismuth telluride and insulating calcium silicate (Bi2Te3-CaSiO3) via constructing multiple interfaces. It is found that a low thermal conductivity is achieved coupling with high electrical conductivity and Seebeck coefficient through adjusting the synergetic effects between Bi2Te3 and CaSiO3 interfaces. A high ZT value (0.72) is obtained at relatively high temperature of 373 K for the composites with 85 wt% Bi2Te3, which is much higher than that of the bulk Bi2Te3 (∼0.59). Accordingly, since only materials of industrial grade were adopted, this work would also provide solid evidence for industrial fabrication of Bi2Te3 based TE materials toward low cost, high performance and large scale commodities.