Nano Science and Nano Technology

Biography

Biography: Dr. Angeline Poulon-Quintin

Abstract

Thermoelectric (TE) materials have received a lot of interest for decades for power generation applications in waste heat recovery or energy harvesting by conversion of waste thermal energy into useful electricity. The performance of TE devices depends on the dimensionless figure of merit ZT = (α²σ/κ)T, where α is the Seebeck coefficient, σ and κ the electrical and thermal conductivities, respectively, and T is the absolute temperature. Many TE materials have been developed such as Bi₂Te₃, PbTe, Mg₂Si, Zn₄Sb₃, filled skutterudites and SiGe. Among them, skutterudite compounds MX₃ (M = Co, Rh or Ir; X = P, As or Sb) crystalized in the bcc structure Im3 are promising TE materials. The binary skutterudite CoSb₃ exhibits a large Seebeck coefficient and a high electrical conductivity. However, its high thermal conductivity makes it difficult to be an efficient TE material. Nanostructuration is an effective approach to lower thermal conductivity. While physical methods allow high purity microparticles synthesis, solution routes are the most effective methods to produce CoSb₃ nanoparticles with a few nanometer size and have advantages of low cost, low processing temperature (< 300°C) and high reproducibility, allowing possible large-scale production, even if they suffer from long reaction time, multiple reaction steps and impurity presence. Supercritical fluid routes have emerged from the two last decades as novel efficient approaches to synthetize metal nanoparticles with the control of their physicochemical properties as size, morphology, crystallographic structure and composition. We report the first fast and continuous supercritical fluids synthesis of cobalt antimony intermetallic nanoparticles (4-5 nm) with a high reliability.