Compositional Difference of Thermoelectric Properties in Ag₉TlTe₅

Abstract

The ternary silver thallium telluride, Ag₉TlTe₅, was reported to exhibit an excellent thermoelectric performance because of its extremely low thermal conductivity. We have studied the effect of the compositional difference on thermoelectric properties of Ag₉TlTe₅ by measuring the thermoelectric data on polycrystalline samples with three compositions. A minimal compositional deviation from the stoichiometric Ag₉TlTe₅ improved the power factor while the thermal conductivity remained extremely low, leading to an enhancement of the thermoelectric figure of merit.