High-temperature electrical and thermal transport behaviors of In2O3-based ceramics by Zn-Sn co-substitution.

We report remarkably the enhanced thermoelectric performance of Sn-Zn co-doped In2O3 that were synthesized by a solid-state reaction followed by spark plasma sintering in the mid-temperature range. The X-ray diffraction study indicates that Sn and Zn were successfully co-substituted at the In site without forming any additional phase even at 8% doping concentration. The co-substitution shows a significant increase in the electrical conductivity by band structure modification resulting in a significantly enhanced power factor. The point defect engineering combined with nanostructuring using a high energy ball milling suppressed the lattice thermal conductivity, which eventually resulted in an increased <italic>ZT</italic> value of 0.32 at 973 K, that is, about 7 times higher than that of pure In2O3. Thus, this study demonstrates the important role of co-substitution in improving the thermoelectric properties of n-type oxides. [ABSTRACT FROM AUTHOR]