Synthesis, SPS processing and low temperature transport properties of polycrystalline FeSb2 with nano-scale grains

FeSb2 nanocrystals were synthesized by employing an ethanol-mediated surfactant-free solvothermal approach and subsequently densified to form dense polycrystalline Pnnm FeSb2 with nano-grains employing spark plasma sintering (SPS). Structural and low temperature transport properties of nanostructured polycrystalline FeSb2 were investigated and compared with that of bulk FeSb2. The nanostructured FeSb2 had a much lower thermal conductivity, particularly below 150 K, compared to bulk FeSb2 with resistivity values that were comparable to that of the bulk at these temperatures. This resulted in enhanced thermoelectric properties at cryogenic temperatures as compared to that of the bulk. The ability to form nanostructured polycrystalline materials by SPS processing of solution-phase synthesized nanocrystals, together with the resulting enhanced thermoelectric properties, represent proof of concept for this approach for low-temperature thermoelectrics applications. (c) 2014 Elsevier B.V. All rights reserved.