High-temperature thermoelectric properties of nanostructured Ca3Co4O9 thin films

Abstract

We prepared nanostructured Ca3Co4O9 (CCO) thin films by promoting localized epitaxial growth on polycrystalline Al2O3 substrates. The thermoelectric properties of the CCO films were studied in the temperature range 300 to 1023 K. We confirmed that localized epitaxial growth occurred on the seed grains that dominate the (006) plane. The nanostructured CCO thin films were found to have a maximum Seebeck coefficient of 206 mu V/K and a power factor (at 920 K) of 0.514 mW/mK(2). Moreover, the presence of nanostructure was found to reduce the thermal conductivity, and thus, should enhance the overall performance of CCO films in thermoelectric devices. (C) 2011 American Institute of Physics. [doi:10.1063/1.3574530]