气候变化领域集成服务门户(CCPortal): Soft phonon modes from off-center Ge atoms lead to ultralow thermal conductivity and superior thermoelectric performance in n-type PbSe-GeSe

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DOI	10.1039/c8ee01755g
	Soft phonon modes from off-center Ge atoms lead to ultralow thermal conductivity and superior thermoelectric performance in n-type PbSe-GeSe
	Luo Z.-Z.; Hao S.; Zhang X.; Hua X.; Cai S.; Tan G.; Bailey T.P.; Ma R.; Uher C.; Wolverton C.; Dravid V.P.; Yan Q.; Kanatzidis M.G.
发表日期	2018
ISSN	17545692
起始页码	3220
结束页码	3230
卷号	11 期号:11
英文摘要	Historically PbSe has underperformed PbTe in thermoelectric efficiency and has been regarded as an inferior relative to its telluride congener. However, the fifty-fold greater natural abundance of Se relative to Te makes PbSe appealing as a thermoelectric material. We report that the n-type GeSe-alloyed PbSe system achieves a peak figure of merit, ZT, of ∼1.54 at 773 K and maintains ZT values above 1.2 over a broad temperature range from 623 K to 923 K. The highest performing composition is Sb-doped PbSe-12%GeSe, which exhibits an ultralow lattice thermal conductivity of ∼0.36 W m-1 K-1 at 573 K, close to the limit of amorphous PbSe. Theoretical studies reveal that the alloyed Ge2+ atoms prefer to stay at off-center lattice positions, inducing low frequency modes. The Ge atoms also cause the unexpected behavior where the next nearest atom neighbors (6 Pb atoms) oscillate at lower frequencies than in pure PbSe leading to a large reduction of the Debye temperature and acoustic phonon velocity. The Pb0.9955Sb0.0045Se-12%GeSe system also shows Ge-rich precipitates and many aligned dislocations within its microstructure which also contribute to phonon scattering. The resultant average ZT (ZTavg), a broad measure of the material's potential for functional thermoelectric modules, is 1.06 from 400 K to 800 K, the highest among all previously reported n- and p-type PbSe. This value matches or exceeds even those of the best n-type PbTe-based thermoelectric materials. © The Royal Society of Chemistry 2018.
英文关键词	Atoms; Germanium; Germanium compounds; IV-VI semiconductors; Phonons; Thermal conductivity; Thermoelectric equipment; Thermoelectricity; Broad temperature ranges; Lattice thermal conductivity; Low-frequency modes; Lower frequencies; Thermo-Electric materials; Thermo-electric modules; Thermoelectric efficiency; Thermoelectric performance; Lead alloys; energy efficiency; lattice dynamics; microstructure; performance assessment; precipitation (chemistry); reduction; telluride; temperature; thermal conductivity
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/190081
作者单位	School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue639798, Singapore; 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	Luo Z.-Z.,Hao S.,Zhang X.,et al. Soft phonon modes from off-center Ge atoms lead to ultralow thermal conductivity and superior thermoelectric performance in n-type PbSe-GeSe[J],2018,11(11).
APA	Luo Z.-Z..,Hao S..,Zhang X..,Hua X..,Cai S..,...&Kanatzidis M.G..(2018).Soft phonon modes from off-center Ge atoms lead to ultralow thermal conductivity and superior thermoelectric performance in n-type PbSe-GeSe.Energy & Environmental Science,11(11).
MLA	Luo Z.-Z.,et al."Soft phonon modes from off-center Ge atoms lead to ultralow thermal conductivity and superior thermoelectric performance in n-type PbSe-GeSe".Energy & Environmental Science 11.11(2018).