Rare earth ytterbium enhanced thermoelectric properties of p-type Bi0.5Sb1.5Te3

Bi2Te3-based compounds are the benchmark thermoelectric materials working near room temperature. In this study, we synthesize ytterbium (Yb) doped Bi0.5Sb1.5Te3 bulk materials by high energy ball milling and direct current hot pressing. The Yb-doping increases the carrier concentration and suppresses the intrinsic excitation, thus optimizing the electrical transport properties. In addition, the point defects introduced by adding Yb to the lattice behave as extra phonon scattering centres, yielding a reduction in the lattice thermal conductivity. As a result, for the Yb0.0075Bi0.5Sb1.4925Te3 sample, a high zT of similar to 1.3 at 330 K is achieved, and the average zT reaches 0.96 between 303 K and 523 K. Published under license by AIP Publishing.