Synthesis and thermoelectric performance of Ta doped Sr 0.9La 0.1TiO 3 ceramics

Abstract

Ceramics samples of Sr 0.9La 0.1Ti 1− x Ta x O 3 have been synthesized by conventional solid-state reaction method. X-ray powder diffraction characterization indicates that all samples are of single phase with cubic symmetry. The high-temperature electrical resistivity decreases with the increasing of tantalum content except for x = 0.05 sample. Negative Seebeck coefficients have been obtained for all samples, which means conduction mechanism being n-type. The absolute Seebeck coefficient decreases with the increase of tantalum concentration. The power factor decreases with increasing of tantalum substitution. Small amount tantalum doping can reduce the thermal conductivity. The lowest thermal conductivity obtained is 2.9 W/mK for x = 0.03 at 1074 K. The highest thermoelectric figure of merit still observes in Sr 0.9La 0.1TiO 3, reaches 0.29 at 1046 K, which is a relatively higher value in n-type oxide thermoelectric materials.