材料科学
热电效应
Boosting(机器学习)
热电材料
工程物理
光电子学
纳米技术
热导率
计算机科学
热力学
物理
复合材料
机器学习
作者
Lu Yu,Xiaolei Shi,Yuanqing Mao,Wei‐Di Liu,Zhen Ji,Sitong Wei,Zipei Zhang,Weiyu Song,Shuqi Zheng,Huajun Chen
出处
期刊:ACS Nano
[American Chemical Society]
日期:2024-01-02
被引量:1
标识
DOI:10.1021/acsnano.3c09926
摘要
Incorporating donor doping into Mg3Sb1.5Bi0.5 to achieve n-type conductivity is one of the crucial strategies for performance enhancement. In pursuit of higher thermoelectric performance, we herein report co-doping with Te and Y to optimize the thermoelectric properties of Mg3Sb1.5Bi0.5, achieving a peak ZT exceeding 1.7 at 703 K in Y0.01Mg3.19Sb1.5Bi0.47Te0.03. Guided by first-principles calculations for compositional design, we find that Te-doping shifts the Fermi level into the conduction band, resulting in n-type semiconductor behavior, while Y-doping further shifts the Fermi level into the conduction band and reduces the bandgap, leading to enhanced thermoelectric performance with a power factor as high as >20 μW cm–1 K–2. Additionally, through detailed micro/nanostructure characterizations, we discover that Te and Y co-doping induces dense crystal and lattice defects, including local lattice distortions and strains caused by point defects, and densely distributed grain boundaries between nanocrystalline domains. These defects efficiently scatter phonons of various wavelengths, resulting in a low thermal conductivity of 0.83 W m–1 K–1 and ultimately achieving a high ZT. Furthermore, the dense lattice defects induced by co-doping can further strengthen the mechanical performance, which is crucial for its service in devices. This work provides guidance for the composition and structure design of thermoelectric materials.
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