The beneficial influence of tellurium on the thermoelectric properties of Mo{sub 3−x}Fe{sub x}Sb{sub 7}
Various materials of the formulas Mo{sub 3−x}Fe{sub x}Sb{sub 7} and Mo{sub 2.6}Fe{sub 0.4}Sb{sub 7−y}Te{sub y} have been prepared by solid state synthesis at 873 K, starting from the elements in the stoichiometric ratios. The Fe content can be as high as x=0.45, while attempts to incorporate 0.5 Fe lead to the formation of FeSb{sub 2} as a minor side product. At x=0.4, the Te content can vary within 0≤y≤0.75, while the sample with y=1.0 shows FeSb{sub 2} as a minor phase. The materials were densified via hot-pressing, and their thermoelectric properties determined. Increasing both the Fe and the Te content leads to a decrease in the p-type carrier concentration, and thus an increase in Seebeck coefficient and a decrease in both electrical and thermal conductivity. In the end, the best thermoelectric properties were obtained in case of Mo{sub 2.6}Fe{sub 0.4}Sb{sub 6.25}Te{sub 0.75}, i.e. at the edge of the phase range, culminating in a figure-of-merit of zT=0.34 at 800 K. - Graphical abstract: Figure-of-merit of Mo{sub 3−x}Fe{sub x}Sb{sub 7−y}Te{sub y}. - Highlights: • Various Mo{sub 3−x}Fe{sub x}Sb{sub 7−y}Te{sub y} materials were synthesized and characterized. • In each case, the thermoelectric figure-of-merit increases rapidly with increasing temperature. • Higher Fe content and higher Te content cause a decrease of the p-type charge carriers. • With increasing Fe and Te, the Seebeck coefficient increases, while the electrical and thermal conductivity decreases. • Mo{sub 2.6}Fe{sub 0.4}Sb{sub 6.25}Te{sub 0.75} shows the best thermoelectric properties of this series.
- OSTI ID:
- 22334290
- Journal Information:
- Journal of Solid State Chemistry, Vol. 215; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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