On the origin of enhanced thermoelectricity in Fe doped Ca 3Co4O9

Tao Wu, Trevor A. Tyson, Jianming Bai, Kaumudi Pandya, Cherno Jaye, Daniel Fischer

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

Resistivity and Seebeck coefficient measurements on Ca3Co 4-xFexO9 (x = 0, 0.05, 0.1, 0.2 and 0.25) reveal enhanced thermoelectric performance with an optimal x value of 0.2. X-ray diffraction measurements show continuous Fe doping into the host lattice, while X-ray absorption experiments reveal that Fe substitutes for Co in the Ca 2CoO3 (rock salt) block. The Fe substitution for Co produces electron doping. The local structure around Fe in the Ca 2CoO3 block becomes disordered, while the structure in the conducting CoO2 layer becomes more ordered. The structural change in the CoO2 layer plays the key role to enhance the electron transport. The highest ordered structure is achieved at x = 0.2 with the lowest resistivity. Soft X-ray absorption measurements find no Co site spin-state change with Fe doping. Thermoelectric property enhancement associated with doping induced structural change points to a new approach for creating materials with improved ZT in complex oxide systems.

Original languageEnglish (US)
Pages (from-to)4114-4121
Number of pages8
JournalJournal of Materials Chemistry C
Volume1
Issue number26
DOIs
StatePublished - Jul 14 2013

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Chemistry

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