High-Pressure Torsion to Improve Thermoelectric Efficiency of Clathrates?

Author(s)
Xinlin Yan, Matthias Falmbigl, Gerda Rogl, Andrij Grytsiv, A. Prokofiev, Ernst Bauer, Peter Franz Rogl, Michael Zehetbauer, Silke Paschen
Abstract

High-pressure torsion (HPT), as a technique to produce severe plastic deformation, has been proven effective to improve the thermoelectric performance of skutterudites. In this report, we present microstructural and thermoelectric properties of the clathrate Ba8Cu3.5Ge41In1.5 processed by HPT. The sample was synthesized from high-purity elements, subsequently annealed, ball milled, and hot pressed, and finally subject to HPT. Compared with the ball-milled and hot-pressed sample, the HPT-processed sample has higher electrical resistivity and Seebeck coefficient, and lower thermal conductivity, electron concentration, and mobility, which is attributed to the reduced grain size and increased density of dislocations, point defects, and cracks. No essential improvement of the dimensionless thermoelectric figure of merit is observed in the investigated temperature range, questioning the universal versatility of this technique for improvement of thermoelectric materials.

Organisation(s)
Department of Physical Chemistry, Physics of Nanostructured Materials
External organisation(s)
Technische Universität Wien
Journal
Journal of Electronic Materials
Volume
42
Pages
1330-1334
No. of pages
5
ISSN
0361-5235
DOI
https://doi.org/10.1007/s11664-012-2440-8
Publication date
2013
Peer reviewed
Yes
Austrian Fields of Science 2012
104017 Physical chemistry, 210006 Nanotechnology
Portal url
https://ucrisportal.univie.ac.at/en/publications/highpressure-torsion-to-improve-thermoelectric-efficiency-of-clathrates(a1adf718-7813-4696-9d3b-d078b98d7e91).html