Evolution of defect structures leading to high ZT in GeTe-based thermoelectric materials

GeTe is a promising mid-temperature thermoelectric compound but inevitably contains excessive Ge vacancies hindering its performance maximization. This work reveals that significant enhancement in the dimensionless figure of merit ( ZT ) could be realized by defect structure engineering from point d...

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Vydané v:Nature communications Ročník 13; číslo 1; s. 6087 - 9
Hlavní autori: Jiang, Yilin, Dong, Jinfeng, Zhuang, Hua-Lu, Yu, Jincheng, Su, Bin, Li, Hezhang, Pei, Jun, Sun, Fu-Hua, Zhou, Min, Hu, Haihua, Li, Jing-Wei, Han, Zhanran, Zhang, Bo-Ping, Mori, Takao, Li, Jing-Feng
Médium: Journal Article
Jazyk:English
Vydavateľské údaje: London Nature Publishing Group UK 14.10.2022
Nature Publishing Group
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Predmet:
147/143
639/301/1005/1007
639/301/299/2736
Carrier mobility
Evolution
Figure of merit
Humanities and Social Sciences
Lattice vacancies
Lead free
Maximization
multidisciplinary
Optimization
Performance enhancement
Point defects
Power factor
Scattering
Science
Science (multidisciplinary)
Synergistic effect
Thermal conductivity
Thermoelectric materials
Transport properties
ISSN:2041-1723, 2041-1723
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Shrnutí:GeTe is a promising mid-temperature thermoelectric compound but inevitably contains excessive Ge vacancies hindering its performance maximization. This work reveals that significant enhancement in the dimensionless figure of merit ( ZT ) could be realized by defect structure engineering from point defects to line and plane defects of Ge vacancies. The evolved defects including dislocations and nanodomains enhance phonon scattering to reduce lattice thermal conductivity in GeTe. The accumulation of cationic vacancies toward the formation of dislocations and planar defects weakens the scattering against electronic carriers, securing the carrier mobility and power factor. This synergistic effect on electronic and thermal transport properties remarkably increases the quality factor. As a result, a maximum ZT  > 2.3 at 648 K and a record-high average ZT (300-798 K) were obtained for Bi 0.07 Ge 0.90 Te in lead-free GeTe-based compounds. This work demonstrates an important strategy for maximizing the thermoelectric performance of GeTe-based materials by engineering the defect structures, which could also be applied to other thermoelectric materials. The intrinsic high-concentration Ge vacancies in GeTe-based thermoelectric materials hinder their performance maximization. Here, the authors find that defect structure engineering strategy is effective for performance enhancement.
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ISSN:2041-1723
2041-1723
DOI:10.1038/s41467-022-33774-z