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High thermoelectric performance in complex phosphides enabled by stereochemically active lone pair electrons
Shen, Xingchen1,7,8; Xia, Yi2; Wang, Guiwen3; Zhou, Fei4; Ozolins, Vidvuds5,6; Lu, Xu1; Wang, Guoyu7,8; Zhou, Xiaoyuan1,3
2018-12-28
摘要We propose a new strategy to design high performance thermoelectric materials with stereochemically active lone pair electrons. This novel concept is experimentally demonstrated in the cluster compounds Ag6Ge10(1-x)Ga10xP12 with x = 0.0, 0.01, 0.03, 0.04. A maximum power factor of 13 W cm(-1) K-2 is achieved after optimizing carrier concentration. Density functional theory calculations reveal that the stereochemically active lone pair electrons from s orbitals of Ge give rise to a peak in the density of states near the valence band maximum, a feature that is beneficial for achieving a high power factor. Experimental results also confirm the theoretically predicted relatively low thermal conductivity of about 1 W m(-1) K-1 arising from the rattling vibrations associated with Ag-6 clusters, which create low-frequency localized optical phonons in the acoustic region and thus enable strong anharmonic phonon scattering. The highest zT value attained here is 0.65 at 723 K for the x = 0.03 sample, a record high value for polycrystalline phosphide and still with significant potential for optimization.
DOI10.1039/c8ta08448c
发表期刊JOURNAL OF MATERIALS CHEMISTRY A
ISSN2050-7488
卷号6期号:48页码:24877-24884
通讯作者Lu, Xu(luxu@cqu.edu.cn) ; Wang, Guoyu(guoyuw@cigit.ac.cn) ; Zhou, Xiaoyuan(xiaoyuan2013@cqu.edu.cn)
收录类别SCI
WOS记录号WOS:000453550700019
语种英语