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Publication Citation: RECENT INVESTIGATIONS OF Sr-Ca-Co-O THERMOELECTRIC MATERIALS

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Author(s): Winnie K. Wong-Ng; Guangyao Liu; Makoto Otani; Evan L. Thomas; Nathan Lowhorn; Martin L. Green; James A. Kaduk;
Title: RECENT INVESTIGATIONS OF Sr-Ca-Co-O THERMOELECTRIC MATERIALS
Published: December 21, 2009
Abstract: Three low-dimension cobaltites in the Sr-Ca-Co-O system have been studied for their structure and thermoelectric properties. Using x-ray pole figure construction technique, a Ca3Co4O9 thin film showed excellent fiber texture but no ab in-plane texture. The fiber texture is mainly responsible for the excellent thermoelectric properties. Our study of a high-throughput combinatorial thin film (synthesized using Pulsed Laser Deposition) with a custom-built power factor screening tool demonstrated that the La substitution in the Ca-site of Ca3Co4O9 increases Seebeck coefficient and resistivity due to decrease of hole concentration. The Sr-substitution on the Ca-site increases the carrier mobility, therefore lower resistivity of the film. The homologous compounds Can+2ConCo O3n+3 and Srn+2ConCo O3n+3 consist of parallel 1-dimensional (Co2O6)6- chains that are built by successive alternating face-sharing CoO6 trigonal prism and n units of CoO6 octahedra along the c-axis. However, due to the high resistivity of these compounds, they will unlikely yield ZT values comparable to that of Ca3Co4O9.
Conference: Materials Science and Technology 2008 Conference and Exhibit (MS&T08)
Proceedings: International Symposium on Advanced Dielectric Materials and Electronic Devices
Pages: pp. 47 - 58
Location: Pittsburgh, PA
Dates: October 5-10, 2008
Keywords: thermoelectric; Ca3Co4O9; Can+2ConCo O3n+3; Srn+2ConCo O3n+3
Research Areas: Materials Science