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Multiple Effects Promoting the Thermoelectric Performance of SnTe by Alloying with CuSbTe2 and CuBiTe2
He, Wenlu1; Li, Nanhai1,2; Wang, Huan1; Wang, Guiwen3; Wang, Guoyu2; Lu, Xu1; Zhou, Xiaoyuan1,3
2021-11-10
摘要In a SnTe-based thermoelectric material, the naturally high hole concentration caused by cation vacancies and high total thermal conductivity seriously hinder its thermoelectric performance. A recent work shows that alloying SnTe with other compounds from the I-V-VI2 family (I = Ag, Na; V = Sb, Bi; VI = Te) can be considered an effective strategy to boost the figure of merit efficiently via the synergy of manipulating hole concentration and lowering lattice thermal conductivity. Herein, we present a markedly enhanced thermoelectric performance in p-type SnTe through CuPnTe(2) (Pn = Sb, Bi) alloying. Moreover, we found that the alloying with both CuSbTe2 and CuBiTe2 can facilitate the valence band convergence of SnTe, but their relative influence is different. Interestingly, compared to CuBiTe2, alloying with CuSbTe2 increases the carrier concentration of SnTe, which suppresses the bipolar effect. Ultimately, under the positive effect of valence band convergence, increased vacancy concentration, and decreased lattice thermal conductivity, compounds with a nominal composition of (SnTe)(0.90)(CuSbTe2)(0.10) attains a peak zT of similar to 1.26 at 823 K. In contrast, the thermoelectric performance of (SnTe)(1-x)(CuBiTe2)(x) is restricted by the reduced carrier concentration and diminished band gap, showing only a humble maximum zT value of similar to 0.91 at 823 K in the sample with a nominal composition of (SnTe)(0.96)(CuBiTe2)(0.04). These results demonstrate the multiple effects on thermoelectric transport during the formation of complex solid solutions.
关键词solid solutions thermoelectrics band convergence transport coefficients weighted mobility carrier concentration
DOI10.1021/acsami.1c15614
发表期刊ACS APPLIED MATERIALS & INTERFACES
ISSN1944-8244
卷号13期号:44页码:52775-52782
通讯作者Wang, Guiwen(gwwang@cqu.edu.cn) ; Wang, Guoyu(guoyuw@cigit.ac.cn) ; Lu, Xu(luxu@cqu.edu.cn)
收录类别SCI
WOS记录号WOS:000718271300092
语种英语