Excellent thermoelectric performance achieved over broad temperature plateau in indium-doped SnTe-AgSbTe_2 alloys

摘要

SnTe is deemed as a natural candidate to replace the state-of-the-art thermoelectric material PbTe, due to its low-cost, low-toxicity, and mechanical stability. Nevertheless, both the peak and average figure of merits of SnTe currently are way too inferior as compared to PbTe. In this work, we report that a peak figure of merit as high as similar to 1.3 can be achieved at 873K in p-type SnTe when it is simultaneously doped with Indium and alloyed with AgSbTe2. Moreover, the average figure of merit can be lifted astonishingly from 0.244 up to 0.84, by a factor of 344%, which is the record high value ever reported. The enhanced thermoelectric performance comes from a synergetic improvement of the power factor and reduction of lattice thermal conductivity. The former can be ascribed to the introduction of resonant states by Indium and probable regulation of the valence band structure by AgSbTe2 alloying, while the latter is believed to originate from the vast substitutional point defects at the Sn site by Ag and Sb substitution. Published by AIP Publishing.