Thermoelectric properties of ruddlesden-popper phase n-type semiconducting oxides:: La-, Nd-, and Nb-doped Sr3Ti2O7

초록

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 similar to 0.15, at a 1000 K value was obtained in 5 at.% La-doped Sr3Ti2O7.

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