Enhanced Thermoelectric Properties in the Counter-Doped SnTe System with Strained Endotaxial SrTe

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• 作者：Li-Dong Zhao ; Xiao Zhang ; Haijun Wu ; Gangjian Tan ; Yanling Pei ; Yu Xiao ; Cheng Chang ; Di Wu ; Hang Chi ; Lei Zheng ; Shengkai Gong ; Ctirad Uher ; Jiaqing He ; Mercouri G. Kanatzidis
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：February 24, 2016
• 年：2016
• 卷：138
• 期：7
• 页码：2366-2373
• 全文大小：665K
• ISSN：1520-5126

文摘

We report enhanced thermoelectric performance in SnTe, where significantly improved electrical transport properties and reduced thermal conductivity were achieved simultaneously. The former was obtained from a larger hole Seebeck coefficient through Fermi level tuning by optimizing the carrier concentration with Ga, In, Bi, and Sb dopants, resulting in a power factor of 21 μW cm^–1 K^–2 and ZT of 0.9 at 823 K in Sn_0.97Bi_0.03Te. To reduce the lattice thermal conductivity without deteriorating the hole carrier mobility in Sn_0.97Bi_0.03Te, SrTe was chosen as the second phase to create strained endotaxial nanostructures as phonon scattering centers. As a result, the lattice thermal conductivity decreases strongly from ∼2.0 Wm^–1 K^–1 for Sn_0.97Bi_0.03Te to ∼1.2 Wm^–1 K^–1 as the SrTe content is increased from 0 to 5.0% at room temperature and from ∼1.1 to ∼0.70 Wm^–1 K^–1 at 823 K. For the Sn_0.97Bi_0.03Te-3% SrTe sample, this leads to a ZT of 1.2 at 823 K and a high average ZT (for SnTe) of 0.7 in the temperature range of 300–823 K, suggesting that SnTe is a robust candidate for medium-temperature thermoelectric applications.