Synergistic effects of B-In codoping in zone-melted Bi0.48Sb1.52Te3-based thermoelectric

Bismuth-telluride-based alloys are the unique commercial thermoelectric materials near room temperature, and the commonly used zone-melting method is efficient for the mass production. Since the ZTs of zone-melted samples has stagnated around 1.2 for decades, it is urgent for the scientific and industrial societies to break through this bottleneck. Herein, we report simultaneously improved power factor and ZT values in p-type Bi0.48Sb1.52Te3 materials by the addition of amorphous boron and metal indium. B and In dopants not only effectively increase the hole concentration and the density of state effective mass, leading to a high power factor of 55 mu W cm-1 K-2, but also introduce various phonon scattering centers to obviously suppress the lattice thermal conductivity. The synergistic effects yield a ZTmax of 1.45 at 350 K, as well as a ZTave of 1.20 and sigma S2ave of 41 mu W cm-1 K-2 (300 - 500 K) in the Bi0.48Sb1.515In0.005Te3 + 0.6 wt% B sample, suggesting tiny B-In codoping is a promising strategy for the further development of bismuth telluride thermoelectrics.