气候变化领域集成服务门户(CCPortal): Understanding the thermally activated charge transport in NaPbMSbQm +2(Q = S, Se, Te) thermoelectrics: Weak dielectric screening leads to grain boundary dominated charge carrier scattering

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DOI	10.1039/d0ee00491j
	Understanding the thermally activated charge transport in NaPbMSbQm +2(Q = S, Se, Te) thermoelectrics: Weak dielectric screening leads to grain boundary dominated charge carrier scattering
	Slade T.J.; Grovogui J.A.; Kuo J.J.; Anand S.; Bailey T.P.; Wood M.; Uher C.; Snyder G.J.; Dravid V.P.; Kanatzidis M.G.
发表日期	2020
ISSN	17545692
起始页码	1509
结束页码	1518
卷号	13 期号:5
英文摘要	Many thermoelectric materials feature irregular electrical conductivity with thermally activated transport below ∼600 K and metallic behavior at high temperatures, despite possessing degenerate carrier concentrations. The suppression of the electrical conductivity ultimately degrades the thermoelectric performance on the cold side and limits the device energy conversion efficiency. As such, establishing the origin of the low temperature scattering and developing strategies to mitigate its effect are paramount issues. To date, the correct microscopic description of the low temperature carrier scattering remains an open issue, and there is little work addressing why some thermoelectric materials are more susceptible to the deleterious behavior. Here, we use the promising thermoelectric alloys of PbQ and NaSbQ2 (Q = S, Se, Te) as model systems to address these concerns. We directly show the thermally activated transport stems from the scattering of charge carriers by the grain boundaries (GBs), and that the expected metallic electrical conductivity is recovered by preparing large grained samples with reduced densities of GBs. We furthermore study the electrical properties NaPbmSbSem+2 as a function of NaSbSe2 fraction, as well as those of the chalcogenide analogues, PbTe-NaSbTe2 and PbS-NaSbS2, and demonstrate that the strength of GB scattering can be understood by utilizing simple chemical principles. By considering the polarizability of the host atoms, we directly relate the magnitude of GB scattering to the relative degree of charge carrier screening in each material, and demonstrate that GB scattering is strongest in the ionic NaSbQ2-rich compounds and weakest in more polarizable PbQ-rich phases. We finally show how these chemical arguments elegantly explain the strong GB scattering in numerous other thermoelectric materials. By uniting the deleterious charge transport properties exhibited by many different compounds into a common picture, we discuss how our work gives design principles for proper microstructure engineering in emerging thermoelectric materials. © The Royal Society 2020 of Chemistry.
英文关键词	Carrier concentration; Carrier mobility; Conversion efficiency; Electric conductivity; Electron scattering; Grain boundaries; IV-VI semiconductors; Temperature; Thermoelectric energy conversion; Thermoelectric equipment; Thermoelectricity; Developing strategy; Dielectric screening; Electrical conductivity; Microscopic description; Microstructure engineering; Thermo-Electric materials; Thermoelectric alloys; Thermoelectric performance; Carrier transport; activated carbon; detection method; dielectric property; inorganic compound; scattering
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/189722
作者单位	Department of Chemistry, Northwestern University, Evanston, IL 60208, United States; Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, United States; Department of Physics, University of Michigan, Ann Arbor, MI 48109, United States
推荐引用方式 GB/T 7714	Slade T.J.,Grovogui J.A.,Kuo J.J.,et al. Understanding the thermally activated charge transport in NaPbMSbQm +2(Q = S, Se, Te) thermoelectrics: Weak dielectric screening leads to grain boundary dominated charge carrier scattering[J],2020,13(5).
APA	Slade T.J..,Grovogui J.A..,Kuo J.J..,Anand S..,Bailey T.P..,...&Kanatzidis M.G..(2020).Understanding the thermally activated charge transport in NaPbMSbQm +2(Q = S, Se, Te) thermoelectrics: Weak dielectric screening leads to grain boundary dominated charge carrier scattering.Energy & Environmental Science,13(5).
MLA	Slade T.J.,et al."Understanding the thermally activated charge transport in NaPbMSbQm +2(Q = S, Se, Te) thermoelectrics: Weak dielectric screening leads to grain boundary dominated charge carrier scattering".Energy & Environmental Science 13.5(2020).