Synthetic transverse thermoelements made from porous bismuth telluride and single crystal bismuth

Synthetic transverse thermoelements may be produced from materials that have layered structures with two components. It is desirable that the electrical and thermal conductivities should be much greater for one component than for the other. It is also necessary that the longitudinal figure of merit for a conventional couple made from the two components should be high. Here we show that a transverse thermoelement made from single-crystal bismuth and polycrystalline bismuth-antimony telluride largely meets these requirements when the latter material is porous. If the porosity is such that the conductivities have about 20% of their values for the fully dense alloy, the dimensionless transverse figure of merit is over 0.6. (c) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim