Chapters authored
Silver-Antimony-Telluride: From First-Principles Calculations to Thermoelectric Applications
Silver-antimony-telluride (AgSbTe2) based compounds have emerged as a promising class of materials for thermoelectric (TE) power generation at the mid-temperature range. This Chapter demonstrates utilization of first-principles calculations for predicting TE properties of AgSbTe2-based compounds and experimental validations. Predictive calculations of the effects of La-doping on vibrational and electronic properties of AgSbTe2 compounds are performed applying the density functional theory (DFT), and temperature-dependent TE transport coefficients are evaluated applying the Boltzmann transport theory (BTE). Experimentally, model ternary (AgSbTe2) and quaternary (3 at. % La-AgSbTe2) compounds were synthesized, for which TE transport coefficients were measured, indicating that thermal conductivity decreases due to La-alloying. The latter also reduces electrical conductivity and increases Seebeck coefficients. All trends correspond with those predicted from first-principles. Thermal stability issues are essential for TE device operation at service conditions, e.g. changes of matrix composition and second-phase precipitation, and are also addressed in this study on both computational and experimental aspects. It is shown that La-alloying affects TE figure-of-merit positively, e.g., improving from 0.35 up to 0.50 at 260 °C. We highlight the universal aspects of this approach that can be applied for other TE compounds. This enables us screening their performance prior to synthesis in laboratory.
Part of the book: Thermoelectrics for Power Generation