High Thermoelectric Performance SnTe鈥揑n2Te3 Solid Solutions Enabled by Resonant Levels and Strong Vacancy Phonon Scattering

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• 作者：Gangjian Tan ; Wolfgang G. Zeier ; Fengyuan Shi ; Pengli Wang ; G. Jeffery Snyder ; Vinayak P. Dravid ; Mercouri G. Kanatzidis
• 刊名：Chemistry of Materials
• 出版年：2015
• 出版时间：November 24, 2015
• 年：2015
• 卷：27
• 期：22
• 页码：7801-7811
• 全文大小：822K
• ISSN：1520-5002

文摘

Herein, we report a significantly improved thermoelectric figure of merit ZT of 鈭?.1 at 鈭?23 K in p-type SnTe through In₂Te₃ alloying and iodine doping. We propose that the introduction of indium at Sn sites in SnTe creates resonant levels inside the valence bands, thereby considerably increasing the Seebeck coefficients and power factors in the low-to-middle temperature range. Unlike SnTe鈥揑nTe, the SnTe鈥揑n₂Te₃ system displays much lower lattice thermal conductivity. Utilizing a model for point defect scattering, we analyze the origin of the low thermal conductivity in SnTe鈥揑n₂Te₃ and attribute it mainly to the strong vacancy originated phonon scattering between Sn atoms and the vacancies introduced by In₂Te₃ alloying and partly to the interfacial scattering by In-rich nanoprecipitates present in SnTe matrix. By alloying only In₂Te₃ with SnTe, a ZT value of 鈭?.9 at 923 K was achieved. ZT can be further increased to 鈭?.1 at 923 K through adjusting the charge carriers by iodine doping at Te sites.