Thermoelectric SnTe with Band Convergence, Dense Dislocations, and Interstitials through Sn Self-Compensation and Mn Alloying

Fengkai Guo; Bo Cui; Yuan Liu; Xianfu Meng; Jian Cao; Yang Zhang; Ran He; Weishu Liu; Haijun Wu; Stephen J Pennycook; Wei Cai; Jiehe Sui

doi:10.1002/smll.201802615

Thermoelectric SnTe with Band Convergence, Dense Dislocations, and Interstitials through Sn Self-Compensation and Mn Alloying

Small. 2018 Sep;14(37):e1802615. doi: 10.1002/smll.201802615. Epub 2018 Aug 17.

Authors

Fengkai Guo¹, Bo Cui¹, Yuan Liu², Xianfu Meng¹, Jian Cao¹, Yang Zhang³, Ran He⁴, Weishu Liu⁵, Haijun Wu³, Stephen J Pennycook³, Wei Cai¹, Jiehe Sui¹

Affiliations

¹ State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin, 150001, China.
² Department of Physics and TcSUH, University of Houston, Houston, TX, 77204, USA.
³ Department of Materials Science and Engineering, National University of Singapore, Singapore 117575, Singapore.
⁴ Institute for Metallic Materials, IFW-Dresden, Dresden, 01069, Germany.
⁵ Department of Materials Science and Engineering, South University of Science and Technology of China, Shenzhen, Guangdong, 518055, China.

PMID: 30117655
DOI: 10.1002/smll.201802615

Abstract

SnTe is known as an eco-friendly analogue of PbTe without toxic elements. However, the application potentials of pure SnTe are limited because of its high hole carrier concentration derived from intrinsic Sn vacancies, which lead to a high electrical thermal conductivity and low Seebeck coefficient. In this study, Sn self-compensation and Mn alloying could significantly improve the Seebeck coefficients in the whole temperature range through simultaneous carrier concentration optimization and band engineering, thereby leading to a large improvement of the power factors. Combining precipitates and atomic-scale interstitials due to Mn alloying with dense dislocations induced by long time annealing, the lattice thermal conductivity is drastically reduced. As a result, an enhanced figure of merit (ZT) of 1.35 is achieved for the composition of Sn_0.94 Mn_0.09 Te at 873 K and the ZT_ave from 300 to 873 K is boosted to 0.78, which is of great significance for practical application. Hitherto, the ZT_max and ZT_ave of this work are the highest values among all single-element-doped SnTe systems.

Keywords: SnTe; band convergence; dislocations; interstitials; self-compensation.

Abstract

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