Achieving ultralow lattice thermal conductivity and improved thermoelectric performance in BiSe by doping

Abstract

Low lattice thermal conductivity materials are desirable for several technologically important applications such as thermoelectrics. In this work, we engineer the thermal conductivity of BiSe, a layer-structured compound exhibiting intrinsically low lattice thermal conductivity. Remarkably, we show that simply by doping, we achieve an ultralow room temperature lattice thermal conductivity of ~ 0.23 W m−1 K−1. The bipolar process is also substantially suppressed. Together with the enhanced Seebeck coefficient, thermoelectric performance is considerably improved reaching a power factor of ~12 μW cm−1 K−2 and peak zT of ~ 0.69 at 570 K in (Bi0.7Sb0.3)(Se0.95Te0.05).