Thermoelectric properties of Ba8Ga16Ge30 with TiO2 nanoinclusions
Journal article, 2012

The effects on thermal and electrical properties of adding small amounts of TiO2 nanoinclusions to bulk Ba8Ga16Ge30 clathrate have been investigated. The thermal properties were analysed using the transient plane source technique and the analysis showed a significant decrease in thermal conductivity as the volume fraction of TiO2 increased from 0 vol. % to 1.2 vol. %. The introduction of TiO2 nanoparticles caused a shift in the peak value of the Seebeck coefficient towards lower temperatures. The maximum value of the Seebeck coefficient was, however, only little affected. The introduction of TiO2 nanoparticles into the bulk Ba8Ga16Ge30 resulted in an increased electrical resistivity of the sample, thus simultaneously reducing the charge carrier contribution to the thermal conductivity, partly explaining the decrease in total thermal conductivity. Due to the large increase in resistivity of the samples, ZT was only somewhat improved for the material with 0.4 vol. % TiO2 while the ZT values of the other materials were lower than for the reference Ba8Ga16Ge30 material without TiO2 nanoparticles. The combined results are consistent with a scenario where the nanoparticle introduction causes a light doping of the semiconductor matrix and an increased concentration of phonon scattering centres.

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Author

Richard Heijl

Chalmers, Chemical and Biological Engineering, Applied Surface Chemistry

Daniel Cederkrantz

Chalmers, Chemical and Biological Engineering, Applied Surface Chemistry

M. Nygren

Stockholm University

Anders Palmqvist

Chalmers, Chemical and Biological Engineering, Applied Surface Chemistry

Journal of Applied Physics

0021-8979 (ISSN) 1089-7550 (eISSN)

Vol. 112 4 044313

Subject Categories

Physical Sciences

DOI

10.1063/1.4748152

More information

Latest update

11/12/2021