Preparation and thermoelectric properties of p- and n-type IrSb3

Abstract

IrSb3 belongs to a large family of compounds with the skutterudite crystal structure (CoAs3). The peritectic decomposition temperature of IrSb3 is 1141 °C. The growth of large crystals of IrSb3 by conventional growth techniques is not straightforward. Single phase, polycrystalline samples were prepared by a liquid‐solid sintering technique. Samples were characterized by microprobe analysis, X‐ray diffractometry and density measurements. As‐prepared IrSb3 samples show p‐type conductivity and n‐type samples were prepared by addition of platinum. Seebeck coefficient, electrical resistivity, thermal conductivity and Hall effect measurements were performed at room temperature and up to 600 °C on selected samples. High p‐type mobilities were measured and a maximum of about 1380 cm2.V−1 .s−1 was measured on a sample with a carrier concentration of 7.1×1018 cm−3. N‐type samples have substantially lower mobilities but very large Seebeck coefficients. A bandgap of 1.18 eV was estimated from high temperature electrical resistivity and Hall effect measurements. The hole and electron effective masses were also estimated. Based on the experimental data obtained, the potential of IrSb3 as a thermoelectric material is discussed.