Improvement in thermoelectric performance of Cu-doped β-rhombohedral boron

Yoshiki Takagiwa, Norihide Kuroda, Erika Imai, Ikuzo Kanazawa, Hiroshi Hyodo, Kohei Soga, Kaoru Kimura

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

The effects of Cu doping on the thermoelectric properties of β-rhombohedral boron have been systematically investigated using nominal compositions of CuxB105 (x= 0-5). The electrical conductivity increases with increasing x up to 5 at.%, whereas the positive Seebeck coefficient decreases because of an increase in the carrier concentration. Consequently, the power factor is enhanced by a factor of four from 22 μW m-1 K-2 (x= 0) to 90 μW m-1 K-2 (x= 4) at 973 K. In addition, Cu doping of the interstitial D and E sites contributes a ~50% reduction in the thermal conductivity from 4.3 W m-1 K-1 (x= 0) to 2.1 W m-1 K-1 (x= 5) at 973 K because of increased numbers of phonon scattering events. The dimensionless figure of merit ZT is also enhanced by a factor of six from 0.006 (x= 0) to 0.038 (x= 4) at 973 K in the p-type material. The ZT value obtained is higher than that of the conventional thermoelectric boride B4C.

Original languageEnglish
Pages (from-to)1066-1069
Number of pages4
JournalMaterials Transactions
Volume57
Issue number7
DOIs
Publication statusPublished - 2016

Keywords

  • Borides
  • Boron
  • Chemical doping
  • Thermoelectric properties

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