Regensburg 2010 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 13: Thermoelectric Thin Films and Nanostructures I
DS 13.6: Vortrag
Dienstag, 23. März 2010, 11:45–12:00, H8
Doped NiTiSn as a n- + p-type thermoelectric material pair in almost one material — •B. Balke, S. Ouardi, M. Schwall, and C. Felser — Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg - University, Mainz, Germany
Excellent n-type XNiSn (ZTmax=1.5) and p-type XCoSb (ZTmax = 0.7) (X = Ti, Zr, Hf) high temperature thermoelectrics were reported recently and reproduced by several groups in Asia (Toshiba, Toyota) and US. But to reach the goal to develop a thermoelectric converter (TEC) beyond the state-of-the-art for power generation one has to overcome several difficulties. The demands are environmental friendliness, low-cost and future availability of raw materials, high efficiency, operating temperature 100 - 700∘C + short time excess temperature up to 800∘C, possibility of industrial processing, and a thermoelectric material pair (n- + p-type) with very similar coefficients of thermal expansion and good thermoelectric compatibility. The half-Heusler materials class does meet nearly all requirements including a high power factor, but a general challenge in improving half-Heuslers is to reduce the comparatively high thermal conductivity. We produced and investigated the thermoelectric properties of doped NiTT′Sn(T = Ti, Zr, Hf, and T′ = Sc, Y, V, Nb) and we were able to reach both goals, reducing the comparatively high thermal conductivity and designing a thermoelectric material pair (n- + p-type) in almost one material. This work was financially supported by the Stiftung für Inovation Rheinland Pfalz.