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Synergistically optimized electrical and thermal transport properties of SnTe via alloying high-solubility MnTe
Ist Teil von
Energy & environmental science, 2015-01, Vol.8 (11), p.3298-3312
Ort / Verlag
United States: Royal Society of Chemistry
Erscheinungsjahr
2015
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
Lead chalcogenides are the most efficient thermoelectric materials. In comparison, SnTe, a lead-free analogue of PbTe, exhibits inferior thermoelectric performance due to low Seebeck coefficient and high thermal conductivity. In this report, we show that we can synergistically optimize the electrical and thermal transport properties of SnTe
via
alloying Mn. We report that the introduction of Mn (0–50%) induces multiple effects on the band structure and microstructure of SnTe: for the former, it can tune the Fermi level and promote the convergence of the two valence bands, concurrently enhancing the Seebeck coefficient; for the latter, it can profoundly modify the microstructure into an all-scale hierarchical architecture (including nanoscale precipitates/MnTe laminates, stacking faults, layered structure, atomic-scale point defects,
etc.
) to scatter phonons with a broad range of mean free paths, strongly reducing the lattice thermal conductivity. Meanwhile, most significantly, the Mn alloying enlarges the energy gap of the conduction band (C band) and the light valence band (L band), thereby suppressing the bipolar thermal conductivity by increasing the band gap. The integration of these effects yields a high
ZT
of 1.3 at 900 K for 17% Mn alloyed SnTe.