气候变化领域集成服务门户(CCPortal): Grain boundary dominated charge transport in Mg3Sb2-based compounds

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DOI	10.1039/c7ee03326e
	Grain boundary dominated charge transport in Mg3Sb2-based compounds
	Kuo J.J.; Kang S.D.; Imasato K.; Tamaki H.; Ohno S.; Kanno T.; Snyder G.J.
发表日期	2018
ISSN	17545692
起始页码	429
结束页码	434
卷号	11 期号:2
英文摘要	Thermally activated mobility near room temperature is a signature of detrimental scattering that limits the efficiency and figure-of-merit zT in thermoelectric semiconductors. This effect has been observed dramatically in Mg3Sb2-based compounds, but also to a lesser extent in other thermoelectric compounds. Processing samples differently or adding impurities such that this effect is less noticeable produces materials with a higher zT. Experiments suggest that the behavior is related to grain boundaries, but impurity scattering has also been proposed. However, conventional models using Matthissen's rule are not able to explain the dramatic change in the temperature dependency of conductivity or drift mobility which is observed in Mg3Sb2-based compounds. We find that it is essential to consider the grain boundary region as an effectively separate phase rather than a scattering center, taking into account the weaker screening in semiconductors compared with classical metals. By modeling a grain boundary phase with a band offset, we successfully reproduce the experimentally observed conductivity versus temperature and thermopower versus conductivity relations, which indicate an improved description of transport. The model shows good agreement with measured grain size dependencies of conductivity, opening up avenues for quantitatively engineering materials with similar behavior. Model estimates predict room for >60% improvement in the room temperature zT of Mg3.2Sb1.5Bi0.49Te0.01 if the grain boundary resistance could be eliminated. © 2018 The Royal Society of Chemistry.
英文关键词	Impurities; Engineering materials; Grain boundary phase; Grain boundary regions; Grain boundary resistance; Near room temperature; Temperature dependencies; Thermoelectric compound; Thermoelectric semiconductor; Grain boundaries; equipment; experimental study; grain boundary; inorganic compound; mobility; numerical model; scattering; temperature effect
语种	英语
来源期刊	Energy & Environmental Science
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/190330
作者单位	Northwestern University, Evanston, IL 60208, United States; California Institute of Technology, Pasadena, CA 91125, United States; Panasonic Corporation, Seika, Kyoto, 619-0237, Japan; Justus-Liebig-University Giessen, Giessen, 35392, Germany
推荐引用方式 GB/T 7714	Kuo J.J.,Kang S.D.,Imasato K.,et al. Grain boundary dominated charge transport in Mg3Sb2-based compounds[J],2018,11(2).
APA	Kuo J.J..,Kang S.D..,Imasato K..,Tamaki H..,Ohno S..,...&Snyder G.J..(2018).Grain boundary dominated charge transport in Mg3Sb2-based compounds.Energy & Environmental Science,11(2).
MLA	Kuo J.J.,et al."Grain boundary dominated charge transport in Mg3Sb2-based compounds".Energy & Environmental Science 11.2(2018).