Excellent Thermoelectric Performance Realized in p-Type Pseudolayered Sb2Te3(GeTe)12 via Rhenium Doping

Abstract

Nowadays, the pseudolayered Germanium antimony telluride (Sb2Te3(GeTe)n), which contains an intrinsically low thermal conductivity, has attracted wide attention as promising intermediate temperature thermoelectric material. However, the relatively low electrical property in some compositions, such as n = 12, limits further investigation of this system. In this work, the transport properties of Sb2Te3(GeTe)12 samples are significantly enhanced due to the optimized hole density by rhenium doping, contributing to the promotion of power factor. Besides, the lattice thermal conductivity of the doped samples decreased sharply due to the point defects and modulated Ge precipitates. As a result, an ultrahigh figure of merit, zT, value of ∼2.25 at 773 K is achieved in a p-type pseudolayered Sb2Te3(Ge0.988Re0.012Te)12 sample. Furthermore, the spherical aberration corrected transmission electron microscope is applied to further study the attribution of high thermoelectric performance in the aspects of characteristic microstructure in this work. The presented method, which optimized electrical properties and reduced lattice thermal conductivity simultaneously with Re doping, can give rise to the fiercer competitiveness of thermoelectric materials with analogous structures.