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High-performance n-type PbSe-Cu2Se thermoelectrics through conduction band engineering and phonon softening

Cited 28 time in Web of Science Cited 29 time in Scopus
Authors
Zhou, Chongjian; Yu, Yuan; Lee, Yong Kyu; Cojocaru-Miredin, Oana; Yoo, Byeongjun; Cho, Sung-Pyo; Im, Jino; Wuttig, Matthias; Hyeon, Taeghwan; Chung, In
Issue Date
2018-11
Citation
Journal of the American Chemical Society, Vol.140 No.45, pp.15535-15545
Abstract
From a structural and economic perspective, tellurium-free PbSe can be an attractive alternative to its more expensive isostructural analogue of PbTe for intermediate temperature power generation. Here we report that PbSe0.998Br0.002-2%Cu2Se exhibits record high peak ZT 1.8 at 723 K and average ZT 1.1 between 300 and 823 K to date for all previously reported n- and p-type PbSe-based materials as well as tellurium-free n-type polycrystalline materials. These even rival the highest reported values for n-type PbTe-based materials. Cu2Se doping not only enhance charge transport properties but also depress thermal conductivity of n-type PbSe. It flattens the edge of the conduction band of PbSe, increases the effective mass of charge carriers, and enlarges the energy band gap, which collectively improve the Seebeck coefficient markedly. This is the first example of manipulating the electronic conduction band to enhance the thermoelectric properties of n-type PbSe. Concurrently, Cu2Se increases the carrier concentration with nearly no loss in carrier mobility, even increasing the electrical conductivity above similar to 423 K. The resulting power factor is ultrahigh, reaching similar to 21-26 ctW cm(-1) K-2 over a wide range of temperature from similar to 423 to 723 K. Cu2Se doping substantially reduces the lattice thermal conductivity to similar to 0.4 W m(-1) K-1 at 773 K, approaching its theoretical amorphous limit. According to first-principles calculations, the achieved ultralow value can be attributed to remarkable acoustic phonon softening at the low-frequency region.
ISSN
0002-7863
URI
http://hdl.handle.net/10371/165874
DOI
https://doi.org/10.1021/jacs.8b10448
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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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