We report on the promising thermoelectric performance of p-type polycrystalline BiCuSeO, which is a layered oxyselenide composed of conductive (Cu2Se2)2− layers that alternate with insulating (Bi2O2)2+ layers. Electrical transport properties can be optimized by substituting Bi3+ with Ca2+. Moreover, BiCuSeO shows very low thermal conductivity in the temperature ranges of 300 (∼0.9 W m−1K−1) to 923 K (∼0.45 W m−1 K−1). These intrinsically low thermal conductivity values may result from the weak chemical bonds of the material as well as the strong anharmonicity of the bonding arrangement. The combination of the optimized power factor and the intrinsically low thermal conductivity results in a high ZT of ∼0.9 at 923 K for Bi0.925Ca0.075CuSeO.
- Yan-Ling Pei
- Jiaqing He
- Li-Dong Zhao