Improving the thermoelectric performance of Ti-doped NbFeSb by substitutional doping of the Sb atoms with the isoelectric and heavy Bi atoms

Abstract

Solute Bi atoms in Nb 0.8 Ti 0.2 FeSb 1− x Bi x samples scatter phonons and increase the effective mass, increasing the ZT within the Bi solubility limit; above this limit, concomitant Sb vacancies disproportionately donate holes, resulting in poor ZT .