Enhancement of Bi2O2Se thermoelectric power factor via Nb doping

Abstract

Bi2O2Se is a promising thermoelectric material, but in its pristine form, its low carrier concentrations (∼1015 cm−3) induce low electrical conductivity and thermoelectric performance. To increase its electrical conductivity, substitution of Nb5+ ions for Bi3+ ions was carried out. Pure and Nb-doped Bi2O2Se were synthesized by solid-state reactions, and XRD analysis, XPS spectra, and FE-SEM were used to verify the synthesis of Bi2-xNbxO2Se. The electrical conductivity, σ, and Seebeck coefficient, S, were used to quantify the thermoelectric performance. As the niobium content increased, the electrical conductivity enhanced, whereas the Seebeck coefficient declined. A maximum power factor value of 7 μW cm−1•K−2 at 473 K was achieved for Bi1.9Nb0.1O2Se, which is ∼2.6 times that of pure Bi2O2Se at the same temperature. © 2020 Elsevier B.V.