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Exceptional Performance Driven by Planar Honeycomb Structure in a New High Temperature Thermoelectric Material BaAgAs
Peng, Kunling1,2; Zhou, Zizhen3,4; Wang, Honghui1,2; Wu, Hong3,4; Ying, Jianjun1,2; Han, Guang5; Lu, Xu3,4; Wang, Guoyu6; Zhou, Xiaoyuan3,4; Chen, Xianhui1,2
2021-04-01
摘要The discovery of new, high-performing thermoelectrics is of vital importance to promoting thermal energy conversion efficiency. Herein, a new p-type thermoelectric material BaAgAs with an exceptional figure of merit (zT) surpassing 1.1 at 970 K is present as a promising candidate for high-temperature applications. Verified by comprehensive experimental and theoretical investigations, BaAgAs possesses two intrinsic features in favoring zT: i) low lattice thermal conductivity, ascribed to the heavy element Ba in a loose mono-hexagonal layer, the large mass fluctuation in the Ag-As honeycomb layer, and the alternately interlayer stacking between mono-hexagonal and honeycomb layers; ii) good electrical properties contributed by multiple band transport, due to the small band offset between two valence band extremums and the strong anisotropic band effective mass. With enhanced phonon-phonon scattering via Sb/Bi substitution on the As sites, the lattice thermal conductivity is minimized, which results in significantly enhanced zT values. Additionally, an inspiring prediction via the first-principles calculation suggests that n-type BaAgAs can potentially outperform its p-type counterpart due to its higher conducting band degeneracy. This study will stimulate intense interests in the exploration of compounds with planar honeycomb structures as new high-performance thermoelectric materials.
关键词BaAgAs multiple band transport planar hexagonal structures planar honeycomb structures thermoelectric materials
DOI10.1002/adfm.202100583
发表期刊ADVANCED FUNCTIONAL MATERIALS
ISSN1616-301X
页码9
通讯作者Zhou, Xiaoyuan(xiaoyuan2013@cqu.edu.cn) ; Chen, Xianhui(chenxh@ustc.edu.cn)
收录类别SCI
WOS记录号WOS:000635841700001
语种英语