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Cu Intercalation and Br Doping to Thermoelectric SnSe2 Lead to Ultrahigh Electron Mobility and Temperature-Independent Power Factor

Cited 7 time in Web of Science Cited 8 time in Scopus
Authors
Zhou, Chongjian; Yu, Yuan; Zhang, Xiangzhao; Cheng, Yudong; Xu, Jingtao; Lee, Yong Kyu; Yoo, Byeongjun; Cojocaru-Mirédin, Oana; Liu, Guiwu; Cho, Sung-Pyo; Wuttig, Matthias; Hyeon, Taeghwan; Chung, In
Issue Date
2020-02
Citation
Advanced Functional Materials, Vol.30 No.6, p. 1908405
Keywords
dual dopingmobilitypower factorSnSe2thermoelectric
Abstract
Due to its single conduction band nature, it is highly challenging to enhance the power factor of SnSe2 by band convergence. Here, it is reported that simultaneous Cu intercalation and Br doping induce strong Cu-Br interaction to connect SnSe2 layers, otherwise isolated, via "electrical bridges." Atom probe tomography analysis confirms a strong attraction between Cu intercalants and Br dopants in the SnSe2 lattice. Density functional theory calculations reveal that this interaction delocalizes electrons confined around Sn-Se covalent bonds and enhances charge transfer across the SnSe2 slabs. These effects dramatically increase electron mobility and concentration. Polycrystalline SnCu0.005Se1.98Br0.02 shows even higher electron mobility than pristine SnSe2 single crystal and the theoretical expectation. This results in significantly improved electrical conductivity without reducing effective mass and Seebeck coefficient, thereby leading to the highest power factor of approximate to 12 mu W cm(-1) K-2 to date for polycrystalline SnSe2 and SnSe. It even surpasses the value for the state-of-the-art n-type SnSe0.985Br0.015 single crystal at elevated temperatures. Surprisingly, the achieved power factor is nearly independent of temperature ranging from 300 to 773 K. The engineering thermoelectric figure of merit ZT(eng) for SnCu0.005Se1.98Br0.02 is approximate to 0.25 between 773 and 300 K, the highest ZT(eng) ever reported for any form of SnSe2-based thermoelectric materials.
ISSN
1616-301X
URI
http://hdl.handle.net/10371/165756
DOI
https://doi.org/10.1002/adfm.201908405
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College of Engineering/Engineering Practice School (공과대학/대학원)Dept. of Chemical and Biological Engineering (화학생물공학부)Journal Papers (저널논문_화학생물공학부)
College of Engineering/Engineering Practice School (공과대학/대학원)Dept. of Chemical and Biological Engineering (화학생물공학부)Chemical Convergence for Energy and Environment (에너지환경 화학융합기술전공)Journal Papers (저널논문_에너지환경 화학융합기술전공)
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