Texturation boosts the thermoelectric performance of BiCuSeO oxyselenides

Abstract

We present a high ZT ∼ 1.4 in textured Bi_0.875Ba_0.125CuSeO obtained by a hot-forging process. The carrier mobility along the direction perpendicular to the pressing direction was significantly increased, resulting in increase in the electrical conductivity and maximization of the power factor at 923 K from 6.3 μW cm⁻¹ K⁻² for the sample before hot-forging to 8.1 μW cm⁻¹ K⁻² after the hot-forging process. Therefore, the maximum ZT was significantly increased from ∼1.1 to 1.4 through texturing for Bi_0.875Ba_0.125CuSeO, which is the highest ZT ever reported among oxygen containing materials.