Tuning Optimum Temperature Range of Bi2 Te3 -Based Thermoelectric Materials by Defect Engineering

Abstract

Bi₂ Te₃ -based solid solutions, which have been widely used as thermoelectric (TE) materials for the room temperature TE refrigeration, are also the potential candidates for the power generators with medium and low-temperature heat sources. Therefore, depending on the applications, Bi₂ Te₃ -based materials are expected to exhibit excellent TE properties in different temperature ranges. Manipulating the point defects in Bi₂ Te₃ -based materials is an effective and important method to realize this purpose. In this review, we focus on how to optimize the TE properties of Bi₂ Te₃ -based TE materials in different temperature ranges by defect engineering. Our calculation results of two-band model revel that tuning the carrier concentration and band gap, which is easily realized by defects engineering, can obtain better TE properties at different temperatures. Then, the typical paradigms about optimizing the TE properties at different temperatures for n-type and p-type Bi₂ Te₃ -based ZM ingots and polycrystals are discussed in the perspective of defects engineering. This review can provide the guidance to improve the TE properties of Bi₂ Te₃ -based materials at different temperatures by defects engineering.

Keywords: antisite defects; bismuth tellurides; doping; point defects; thermoelectric.