气候变化领域集成服务门户(CCPortal): Discordant nature of Cd in PbSe: Off-centering and core-shell nanoscale CdSe precipitates lead to high thermoelectric performance

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DOI	10.1039/c9ee03087e
	Discordant nature of Cd in PbSe: Off-centering and core-shell nanoscale CdSe precipitates lead to high thermoelectric performance
	Cai S.; Hao S.; Luo Z.-Z.; Li X.; Hadar I.; Bailey T.P.; Hu X.; Uher C.; Hu Y.-Y.; Wolverton C.; Dravid V.P.; Kanatzidis M.G.
发表日期	2020
ISSN	1754-5692
起始页码	200
结束页码	211
卷号	13 期号:1
英文摘要	We report a novel hierarchical microstructure in the PbSe-CdSe system, which collectively contributes to significant enhancement in thermoelectric performance, with ZTave ∼ 0.83 across the 400-923 K temperature range, the highest reported for p-type, Te-free PbSe systems. We have investigated the local atomic structure as well as the microstructure of a series of PbSe-xCdSe materials, up to x = 10%. We find that the behavior of the Cd atoms in the octahedral rock salt sites is discordant and results in off-center displacement and distortion. Such off-centered Cd in the PbSe matrix creates (1) L-Σ electronic energy band convergence, (2) a flattened L band, both contributing to higher Seebeck coefficients, and (3) enhanced phonon scattering, which leads to lower thermal conductivity. These conclusions are supported by photoemission yield spectroscopy in air (PYSA), solid state 111Cd, 77Se NMR spectroscopy and DFT calculations. Above the solubility limit (>6%CdSe), we also observe endotaxial CdSe nano-precipitates with core-shell architecture formed in PbSe, whose size, distribution and structure gradually change with the Cd content. The nano-precipitates exhibit a zinc blende crystal structure and a tetrahedral shape with significant local strain, but are covered with a thin wurtzite layer along the precipitate/matrix interface, creating a core-shell structure embedded in PbSe. This newly discovered architecture causes a further reduction in lattice thermal conductivity. Moreover, potassium is found to be an effective p-type dopant in the PbSe-CdSe system, leading to an enhanced power factor, a maximum ZT of ∼1.4 at 923 K for Pb0.98K0.02Se-6%CdSe. © 2020 The Royal Society of Chemistry.
语种	英语
scopus关键词	Cadmium; Cadmium compounds; Crystal atomic structure; Hierarchical systems; II-VI semiconductors; IV-VI semiconductors; Lead compounds; Microstructure; Nuclear magnetic resonance spectroscopy; Shells (structures); Tellurium compounds; Thermal conductivity; Thermoelectricity; Zinc sulfide; 77se nmr spectroscopies; Core shell structure; Hierarchical microstructures; Lattice thermal conductivity; Local atomic structures; Photoemission yield spectroscopies; Thermoelectric performance; Zinc blende crystal structure; Selenium compounds; cadmium; crystal structure; electrical conductivity; lead; nanoparticle; performance assessment; precipitation (chemistry); selenium; thermal power; zinc
来源期刊	Energy and Environmental Science
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/162391
作者单位	Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, United States; Department of Chemistry, Northwestern University, Evanston, IL 60208, United States; School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue639798, Singapore; Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, United States; Department of Physics, University of Michigan, Ann Arbor, MI 48109, United States; NUANCE Center, Northwestern University, Evanston, IL 60208, United States; National High Magnetic Field Laboratory 1800 East Paul Dirac Drive, Tallahassee, FL 32310, United States
推荐引用方式 GB/T 7714	Cai S.,Hao S.,Luo Z.-Z.,et al. Discordant nature of Cd in PbSe: Off-centering and core-shell nanoscale CdSe precipitates lead to high thermoelectric performance[J],2020,13(1).
APA	Cai S..,Hao S..,Luo Z.-Z..,Li X..,Hadar I..,...&Kanatzidis M.G..(2020).Discordant nature of Cd in PbSe: Off-centering and core-shell nanoscale CdSe precipitates lead to high thermoelectric performance.Energy and Environmental Science,13(1).
MLA	Cai S.,et al."Discordant nature of Cd in PbSe: Off-centering and core-shell nanoscale CdSe precipitates lead to high thermoelectric performance".Energy and Environmental Science 13.1(2020).