Phase transition enhanced thermoelectric figure-of-merit in copper chalcogenides

David R. Brown, Tristan Day, Kasper A. Borup, Sebastian Christensen, Bo B. Iversen, G. Jeffrey Snyder

Research output: Contribution to journalArticlepeer-review

84 Scopus citations

Abstract

While thermoelectric materials can be used for solid state cooling, waste heat recovery, and solar electricity generation, low values of the thermoelectric figure of merit, zT, have led to an efficiency too low for widespread use. Thermoelectric effects are characterized by the Seebeck coefficient or thermopower, which is related to the entropy associated with charge transport. For example, coupling spin entropy with the presence of charge carriers has enabled the enhancement of zT in cobalt oxides. We demonstrate that the coupling of a continuous phase transition to carrier transport in Cu2Se over a broad (360-410 K) temperature range results in a dramatic peak in thermopower, an increase in phonon and electron scattering, and a corresponding doubling of zT (to 0.7 at 406 K), and a similar but larger increase over a wider temperature range in the zT of Cu1.97Ag .03Se (almost 1.0 at 400 K). The use of structural entropy for enhanced thermopower could lead to new engineering approaches for thermoelectric materials with high zT and new green applications for thermoelectrics.

Original languageEnglish (US)
Article number052107
JournalAPL Materials
Volume1
Issue number5
DOIs
StatePublished - Nov 2013

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)

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