Thermoelectric Properties of Some Phosphide Skutterudite Materials

Abstract

The synthesis and thermoelectric properties of CoP 3 , CeFe 4 P 12 and CeRu 4 P 12 have been investigated. These compounds were made by recrystallization from Sn flux. The samples were analyzed by x-ray diffraction and electron microprobe analysis for phase purity. Electrical resistivity and Seebeck coefficient measurements showed that all three compounds are p-type semiconductors, in agreement with theoretical predictions and previous literature results. The large difference between the thermal conductivity of the binary and filled compounds can be primarily attributed to the additional phonon scattering by Ce atoms rattling inside the empty cages. The properties of the phosphide compounds are compared to their antimonide analogs and discussed in order to obtain further insights into the transport properties of skutterudite materials. Guidelines for optimizing thermoelectric properties of this class of compounds are also provided.