Optimization of Thermoelectric Performance of Anisotropic AgxSn1−xSe Compounds
SnSe is a promising thermoelectric material due to its ultralow thermal conductivity. However, stoichiometric SnSe compounds exhibit very low intrinsic defect concentration (3 × 1017 cm−3) and poor electrical transport properties, limiting the thermoelectric performance. In the present work, we investigated the effect of Ag dopant on the thermoelectric properties of SnSe. The results demonstrate that all the AgxSn1−xSe compounds exhibited anisotropic thermoelectric properties. The carrier concentration in the AgxSn1−xSe compounds greatly increased with increase of the Ag content, saturating at 1.9 × 1019 cm−3 for Ag0.01Sn0.99Se at room temperature. We found that a maximum zT value of 0.74 was obtained for Ag0.01Sn0.99Se perpendicular to the pressing direction at 823 K, being 23% higher than that of undoped SnSe (zT = 0.6).