Enhanced thermoelectric performance of BiCuSeO by increasing Seebeck coefficient through magnetic ion incorporation

Abstract

Here, a new concept is proposed in which magnetic ions are incorporated into BiCuSeO to obtain a remarkable Seebeck coefficient, higher electrical conductivity and lower thermal conductivity for optimizing thermoelectric performance. We show that the vast increase in the Seebeck coefficient is caused by the introduction of spin entropy by magnetic Ni ions. Meanwhile, Ba and magnetic ion Ni co-doping leads to enhanced electrical conductivity. The remarkably enhanced Seebeck coefficient coupled with enhanced electrical conductivity result in enhanced power factor. Dual-atomic point-defect scattering generates low thermal conductivity (0.54 W m⁻¹ K⁻¹). The enhanced power factor and low thermal conductivity lead to high a ZT of 0.97 at 923 K for Bi_0.875Ba_0.125Cu_0.85Ni_0.15SeO. This study opens a new pathway for broadening and designing prospective thermoelectric materials.