抄録
Innovative progress in oxide thermoelectric materials during the last decade is reviewed. Two strategies for overcoming unfavorable ionic characters of oxides will be presented: 1) achieving high carrier mobility in oxides; 2) profiting from localization and/or correlation of conduction electrons. Zinc oxide and sodium cobaltite are highlighted as the representatives, which respectively show the highest n- and p-type ZT values. The large power factor of Al-doped ZnO, being well comparable to those of the conventional materials such as PbTe and Si-Ge, would be attributed to relatively high carrier mobilities of the oxide mainly due to the covalent characters of the Zn-O bond. Attempts to suppress the unfavorably high phonon thermal conductivity of the ZnO crystal lattice are also introduced. The outstanding p-type thermoelectric properties of NaCo2O4 and a further advance in the performance by controlling the non-stoichiometry of the oxide will be discussed.
