Effect of Nanostructuring on the Thermoelectric Properties of Co0.97Pd0.03Sb3

International audienceWe synthesized n-type CeO2/Co0.97Pd0.03Sb3 composites with nanometric grain sizes (200 nm to 300 nm) by spark plasma sintering in order to promote phonon scattering at grain boundaries. Powdered samples were initially obtained by ball milling Co0.97Pd0.03Sb3 together with x vol.% (x = 0, 0.5, 1, 2) of CeO2 nanoparticles. This additive slows down the grain size growth of the skutterudite matrix which occurs during sintering, thereby contributing to phonon scattering. The nanostructured samples display reduced Hall electron concentration compared with that of the reference Co0.97Pd0.03Sb3 because of Fe contamination by the steel balls and vials. However, the electronic transport properties are nearly identical to those of Co0.98Pd0.02Sb3, which allows for comparison with this latter compound. The lattice thermal conductivity is strongly decreased in nano-Co0.97Pd0.03Sb12 (-40% at 300 K). This results in an enhanced (+32%) ZT value peaking at 0.65 at 650 K in nano-Co0.97Pd0.03Sb12 + 2% CeO2 when compared with micro-Co0.98Pd0.02Sb3

High thermoelectric figure of merit in mesostructured In0.25Co4Sb12 n-type skutterudite

International audienc

Assessment of the thermoelectric performance of polycrystalline p-type SnSe

International audienceWe report the evaluation of the thermoelectric performance of polycrystalline p-type SnSe, a material in which unprecedented values of the thermoelectric figure of merit ZT have been recently discovered in single crystals. Besides anisotropic transport properties, our results confirm that this compound exhibits intrinsically very low thermal conductivity values. The electrical properties show trends typical of lightly doped, intrinsic semiconductors with thermopower values reaching 500 mu V K-1 in a broad temperature range. An orthorhombic-to-orthorhombic transition sets in at 823 K, a temperature at which the power factor reaches its maximum value. A maximum ZT of 0.5 was obtained at 823 K, suggesting that proper optimization of the transport properties of SnSe might lead to higher ZT values. These findings indicate that this system represents an interesting experimental platform for the search of highly efficient thermoelectric materials