Synergistically Optimized Thermoelectric Performance in Bi0.48Sb1.52Te3 by Hot Deformation and Cu Doping

For decades, bismuth telluride (Bi2Te3) based materials have been widely used for room-temperature thermoelectric cooling. However, commercial zone-melted bismuth telluride is facing a big challenge of the dramatically decreased thermoelectric properties at higher temperature, which limits the usage at intermediate temperature. Herein, we report the enhanced thermoelectric properties of p-type bismuth telluride via a synergistic optimization by hot deformation and copper doping. Hot deformation treatment boosts the grain growth and exhibits donor-like effects, leading to improved electronic transport properties. Meanwhile, high-density dislocations and lattice distortions induced by dynamic recrystallization enhance the phonon scattering and significantly reduce the lattice thermal conductivity. In addition, copper doping effectively tunes the carrier concentration, and the generated point defects also reduce the lattice thermal conductivity. As a result, a peak ZT value of 1.1 at 400 K and average ZT of ...