Ternary AgSbTe₂ materials are frequently reported to show a promising thermoelectric performance, due to the intrinsically low lattice thermal conductivity and complex valence band structure. However, stoichiometric AgSbTe₂ is found to be thermodynamically unstable and would partially decompose into Ag₂Te and Sb₂Te₃ during thermal cycling. Instead, Ag_0.366Sb_0.558Te is the composition for stabilizing the single‐phase according to the Ag₂Te‐Sb₂Te₃ phase diagram, while the thermoelectric transport properties have rarely been reported and are the focus of this work. Sn/Sb substitution is found to effectively increase not only the carrier concentration from ≈5 × 10¹⁹ cm⁻³ to ≈4 × 10²¹ cm⁻³, but also the density‐of‐states effective mass, leading to an enhanced Seebeck coefficient along with a decreased carrier mobility. Single parabolic band (SPB) model with acoustic phonon scattering enables a good understanding on the charge transport. The increased carrier concentration effectively suppresses the bipolar effect at high temperatures. As a result, a peak zT of ≈1.3 and an average of ≈0.9 are achieved.

中文翻译：

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Ag0.366Sb0.558Te的热电性能评估

由于本质上较低的晶格热导率和复杂的价带结构，三元AgSbTe ₂材料经常显示出令人鼓舞的热电性能。然而，发现化学计量的AgSbTe ₂在热力学上是不稳定的，并且在热循环期间会部分分解成Ag ₂ Te和Sb ₂ Te ₃。相反，Ag _0.366 Sb _0.558 Te是根据Ag ₂ Te-Sb ₂ Te ₃稳定单相的成分相图，而热电输运特性鲜有报道，是这项工作的重点。发现Sn / Sb替代不仅可以有效地将载流子浓度从≈5×10 ¹⁹ cm ^-3增加到≈4×10 ²¹ cm ^-3，而且可以有效地提高状态密度，从而提高塞贝克系数以及降低的载流子迁移率。具有声子散射的单抛物线带（SPB）模型使您可以更好地了解电荷传输。增加的载流子浓度有效地抑制了高温下的双极效应。结果，获得的峰值zT约为1.3，平均值约为0.9。