Thermoelectric Transport Properties of TmAgxCu1-xTe2 solid solutions

Intrinsic partial occupation of Cu induces strong phonon scattering for an extremely low lattice thermal conductivity in TmCuTe2, which leads this material to be a promising candidate for thermoelectric applications. This work focus on the electronic and phononic transport properties of TmCuTe2 with Agalloying on the Cu site. Such a Ag/Cu substitution is found to enable a decrease in Hall carrier concentration from 14 x 10(19) to 8 x 10(19) cm(-3) for an evaluation of the charge transport based on a single parabolic band (SPB) model with acoustic scattering. In addition, Ag-substitution simultaneously introduces Cu/Ag point defects for extra phonon scattering, leading the lattice thermal conductivity to be as low as similar to 0.25 W/m-K in a broad temperature. The optimization in carrier concentration and the reduction in lattice thermal conductivity contribute to a similar to 40% improvement in average thermoelectric figure of merit (zT). The determination of band parameters enables a guidance for further advancements in this promising thermoelectric material. (C) 2020 The Chinese Ceramic Society. Production and hosting by Elsevier B.V.

Automated summary

In this study, Ag alloying on the Cu site in TmCuTe2 is found to optimize carrier concentration and reduce lattice thermal conductivity, leading to a significant improvement in thermoelectric figure of merit.