Abstract
Isoelectronic heavy elemental substitutions are generally preferred for enhancing the phonon scattering in a material without deteriorating its electrical transport. In this work, we demonstrate the efficacy and contrasting role of bismuth, an isoelectronic substitute of antimony, for enhancing the thermoelectric transport in structurally ordered cubic VFeSb half-Heusler. Despite its limited solubility, Bi-substitution at Sb-site, was found to be effective in enhancing the electrical power factor near room temperature. Alongside, synergistic lowering of lattice thermal conductivity was observed due to point defect scattering of phonons by Bi-induced mass and strain fluctuations. The electronic transport properties of nominal compositions and effects of Bi-doping induced disorder were evaluated using the Korringa–Kohn–Rostoker method with a coherent potential approximation (KKR-CPA). A highest thermoelectric figure-of-merit ( zT ) ~ 0.22 at 478 K was attained with improved weighted mobility and quality factor for optimally doped VFeSb 0.98 Bi 0.02 half-Heusler alloy making them prospective compositions for near room temperature thermoelectric applications. • Contrasting role of bismuth as prospective substitute for isovalent antimony in Sb-based half-Heusler. • High-power factor > 3.0 × 10 −3 Wm −1 K −2 at room temperature. • Lattice thermal conductivity reduction by point defect scattering in Bi-substituted VFeSb alloys. • Enhanced weighted mobility, thermoelectric quality factor and zT in Bi-substituted VFeSb alloys.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.