Higher-order anharmonicity leads to ultra-low thermal conductivity and high output power density of SnTe-based thermoelectric materials and modules

Teng Wang, Kunpeng Dou, Hongchao Wang, Jiyong Kim, Xue Wang, Wenbin Su, Tingting Chen, Woochul Kim, Chunlei Wang

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5 Citations (Scopus)

Abstract

Higher-order anharmonicity is found in copper and manganese doped tin telluride (SnTe) alloys, and its effect on thermoelectric performance is systematically studied. Analyzation of thermal expansion shows that the ionic potential not only consists of cubic term, but also quartic term. Short phonon lifetime derived from more diffused peak of Brillouin spectrometer results from the higher-order anharmonicity. As a result, an ultra-low lattice thermal conductivity of 0.5 Wm−1K−1 is achieved. Soft optical phonon mode was observed from Raman spectrometer, the transverse optical - longitudinal acoustic phonon interaction may be the reason for the enhanced anharmonicity. Combining with the enlarged power factor caused by band convergence, the highest figure of merit reaches 1.3 at 873 K for doped samples. Additionally, the large temperature difference of 600 K and high output power densities of 291 mWmm−3 of simulated SnTe uni-leg module are achieved. This work supplies way for revealing the anharmonicity experimentally, and proves modification of intrinsic anharmonicity is an avenue for enhancing the thermoelectric performance of SnTe alloys.

Original languageEnglish
Article number100748
JournalMaterials Today Physics
Volume26
DOIs
Publication statusPublished - 2022 Sept

Bibliographical note

Funding Information:
The work is financially supported by National Key R&D Program of China of 2017YFE0195200 , the Natural Science Fund of China under grant Nos. 51871134 , 52171216 and 5201101703 , the Science Fund of Shandong Province under grant No. ZR2019MEM007 , Qilu Young Scholar Program of Shandong University and a National Research Foundation of Korea (NRF) grant funded by the Korean Government ( MSIP ) ( NRF-2018K1A3A1A20026439 , 2021R1A4A1032129 ). The authors also thank Prof. Shishou Kang and Wenjun Zhang from School of Physics of Shandong University for helping with measurement and analysis of Brillouin scattering spectrometers.

Publisher Copyright:
© 2022 Elsevier Ltd

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Energy (miscellaneous)
  • Physics and Astronomy (miscellaneous)

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