Thermoelectric Properties of Ruddlesden–Popper Phase n-Type Semiconducting Oxides: La-, Nd-, and Nb-Doped Sr3Ti2O7
We report herein on Ruddlesden–Popper-type doped Srn+1TinO3n+1 (n=2) as a potential candidate for n-type thermoelectric (TE) oxides. The TE properties of 5 at.% La-, Nd-, and Nb-doped Sr3Ti2O7 polycrystalline ceramics were investigated and the origin of Seebeck coefficient was discussed from the viewpoint of the symmetry of TiO6 octahedra. A significant reduction in the lattice thermal conductivity was observed by the enhancement of phonon scattering at SrO/(SrTiO3)n interfaces originating from the inherent superlattice structure, and the maximum dimensionless figure of merit, ZT∼0.15, at a 1000 K value was obtained in 5 at.% La-doped Sr3Ti2O7.
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Document Type: Research Article
CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi 332-0012, Japan
Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan
Frontier Collaborative Research Center, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8503, Japan
Publication date: 2007-08-01