Complex oxide materials for potential thermoelectric applications

Layered CoO2 materials are excellent candidates for potential thermoelectric applications. Their single crystals show good p-type thermoelectric properties at temperatures higher than 800 K in air. Recently, the mechanism of thermoelectric properties was clarified through a discussion of electronic and crystallographic structure. In order to fabricate thermoelectric modules possessing good power-gene ration properties, thermoelectric materials and metallic electrodes must be connected with low contact resistance and high mechanical strength. It has been found that good junctions can be formed using Ag paste including p- and n-type oxide powders. The role of spin entropy contributions to thermopower will be presented, in connection with strong electron correlation and triangular lattices.