Enhancement in thermoelectric properties of FeSb2 by Sb site deficiency

•Introduction of point defects (in the form of Sb site deficiency) for improving the thermoelectric properties of FeSb2.•A Sb deficiency to the tune of 20% leads to an enhancement in the values of power factor (S2σ) by a factor of 13 at 35 K.•A Sb deficiency to the tune of 20% leads to the suppression of cumulative thermal conductivity (κ) by a factor of 4 at 35 K.•Our results provide ample motivation for exploring the role of Sb site deficiency in single crystals and hot-pressed polycrystalline samples of FeSb2.

We report a strategy based on introduction of point defects for improving the thermoelectric properties of FeSb2, a promising candidate for low temperature applications. Introduction of Sb deficiency to the tune of 20% leads to enhancement in the values of electrical conductivity (σ) and Seebeck coefficient (S) accompanied with a concomitant suppression in lattice thermal conductivity (κlat) values in samples prepared using conventional solid state reaction route. These observations in polycrystalline FeSb2-x provides ample motivation for a dedicated exploration of thermoelectric behavior of the corresponding single crystalline as well as hot-pressed polycrystalline counterparts.

Graphical abstractA strategy based on the introduction of Sb site deficiency in FeSb2−x for co-optimization of electronic (le) and phononic (lph) mean free paths for improving thermoelectric behavior.Figure optionsDownload full-size imageDownload as PowerPoint slide