Synthesis and Characterization of Nanocrystalline FeSb2 for Thermoelectric Applications

Abstract

AbstractWe report an ethanol‐mediated surfactant‐free solvothermal synthesis of phase‐pure Pnmm FeSb2 nanocrystals with an average size of 40 nm. The capping free growth of the nanocrystals resulted in the formation of inherent orthorhombic shapes. The nanocrystals were densified by spark plasma sintering to prepare a polycrystalline bulk material that consisted of 40–200 nm FeSb2 nanocrystal domains (nanocomposite). Low‐temperature Seebeck coefficient, resisitivity, and thermal conductivity were measured on parallelopipeds cut from the densified specimen and compared to bulk FeSb2 prepared by a solid‐state synthesis process. The FeSb2 nanocomposite showed a large reduction in lattice thermal conductivity relative to the bulk due to significant grain‐boundary phonon scattering. If one notes that the solution‐phase synthesis of Pnnm FeSb2 nanocrystals is accounted here for the first time and the low‐temperature thermoelectric properties indicates a significant reduction in lattice thermal conductivity for this material, this work represents an important step towards optimizing thermoelectric properties for cooling applications.