Relating phase transition heat capacity to thermal conductivity and effusivity in Cu2Se

Brown, D. R.California Institute of Technology (Caltech),United States Department of Energy (author)

Accurate measurement of thermal conductivity is essential to determine the thermoelectric figure-of-merit, zT. Near the phase transition of Cu2Se at 410 K, the transport properties change rapidly with temperature, and there is a concurrent peak in measured heat capacity from differential scanning calorimetry (DSC). Interpreting the origin as a broad increase in heat capacity or as a transient resulted in a three-fold difference in the reported zT in two recent publications. To resolve this discrepancy, thermal effusivity was deduced from thermal conductivity and diffusivity measurements via the transient plane source (TPS) method and compared with that calculated from thermal diffusivity and the two interpretations of the DSC data for heat capacity. The comparison shows that the DSC measurement gave the heat capacity relevant for calculation of the thermal conductivity of Cu2Se. The thermal conductivity calculated this way follows the electronic contribution to thermal conductivity closely, and hence the main cause of the zT peak is concluded to be the enhanced Seebeck coefficient.

Heijl, Richard,1984Chalmers tekniska högskola,Chalmers University of Technology(Swepub:cth)kf03heri (author)
Borup, K. A.Århus Universitet,Aarhus University (author)
Iversen, B. B.Århus Universitet,Aarhus University (author)
Palmqvist, Anders,1966Århus Universitet,Aarhus University(Swepub:cth)adde (author)
Snyder, G. J.Northwestern University,California Institute of Technology (Caltech) (author)
California Institute of Technology (Caltech)United States Department of Energy (creator_code:org_t)

In:Physica Status Solidi - Rapid Research Letetrs: Wiley10:8, s. 618-6211862-62541862-6270

By the author/editor: Brown, D. R.; Heijl, Richard, ...; Borup, K. A.; Iversen, B. B.; Palmqvist, Ander ...; Snyder, G. J.

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