1. Unusual As–As and Sb–Sb Bonding in Thermoelectric Materials
H. Kleinke, Department of Chemistry, University of Waterloo, Waterloo, ON N2L 3G1
Many thermoelectric materials are based on tellurides or antimonides.
The antimonides all exhibit unusual Sb–Sb interactions, e.g. linear chains in
b-Zn4Sb3, linear Sb37– ions in Yb14MnSb11 or planar Sb4 rectangles in the filled skutterudites. In Mo3Sb5Te2, the squares are interconnected to form empty cubes, where the edges correspond to weak so-called half ("hypervalent"
one-electron) bonds. As such, Mo3Sb5Te2 should be an intrinsic semiconductor.
Ni0.06Mo3Sb5.4Te1.6
Fe0.05Mo3Sb5.4Te1.6
Mo3Sb5.4Te1.6
We succeeded in optimizing the thermoelectric properties of Mo3Sb5Te2 by adjusting the Sb/Te ratio and by intercalating small amount of Fe and Ni into the empty Sb8 cubes. Next steps will include attempts to lower the thermal conductivity via nanostructuring.
H. Xu, K. M. Kleinke, T. Holgate, D. Rossouw, G. Botton, T. M. Tritt, H. Kleinke, J. Alloys Compd. 504, 314 (2010).