Abstract. Bulk AgPb_mSbTe_2+m compounds exhibit outstanding thermoelectric properties. It is believed that their preparation by a higher cooling rate could improve the homogeneity of these materials, and thereby one expects a certain impact on their thermoelectric properties. We have prepared AgPb₁₈Sb_1−xTe₂₀ compounds where x = 0.0, 0.1, 0.3 and 0.5 by quenching the melts in liquid nitrogen. High-resolution transmission electron microscopy has confirmed that the homogeneity of the samples is improved with respect to the samples prepared by furnace cooling. The decrease in the electric conductivity and the increase in the absolute value of the Seebeck coefficient, we ascribe to the improved homogeneity of the samples. The same effects on the conductivity and on the Seebeck coefficient are obtained with increasing Sb content. The influence of the Sb concentration are interpreted as follows: the number of Ag–Sb pairs and thereby the widening of the energy band increase with increasing Sb content.

Print publication: Issue 11 (7 June 2007)
Received 5 March 2007, in final form 16 April 2007
Published 18 May 2007