【摘 要】
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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
【机 构】
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School of Materials Science and Engineering,Beihang University,Beijing,100191,China;Department of Ph
【出 处】
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第六届海内外中华青年材料科学技术研讨会暨第十五届全国青年材料科学技术研讨会
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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 electrical and thermal transport properties of SnTe via alloying Mn.We report that the introduction of Mn(0-50%)induces multiple effects on 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 microstructure into an all-scale hierarchical architecture(including nanoscale precipitates/MnTe laminates,stacking faults,layered structure,and atomic-scale point defects,etc.)to scatter phonons with broad range of mean free paths,strongly reducing the lattice thermal conductivity.Meanwhile,most significantly,the Mn alloying enlarges the energy gap of conduction band(C band)and light valence band(L band),thereby suppresses the bipolar thermal conductivity through increasing band gap.The integration of these effects yields a high ZT of 1.3 at 900 K for 17%Mn alloyed SnTe.
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