Integrating band engineering with point defect scattering for high thermoelectric performance in Bi2Si2Te6
Integrating band engineering with point defect scattering for high thermoelectric performance in Bi2Si2Te6
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DOI：
10.1016/j.cej.2022.135968
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发表时间：
2022
影响因子：
15.1
通讯作者：
Yue Chen
中科院分区：
文献类型：
--
作者：
Chen Chen;Dongyi Shen;Chengliang Xia;Zongwei Zhang;Wenxuan Wang;Qian Zhang;Yue Chen
A layer-structure compound Bi 2 Si 2 Te 6 is introduced as a promising thermoelectric material. The intrinsic low lattice thermal conductivity of Bi 2 Si 2 Te 6 is because of.the low phonon group velocities near the Γ point and the overlap of optical and acoustic phonon branches. A further decreased thermal conductivity is obtained by.alloying Sb at the Bi site for the additional point-defect scattering of phonons. This Sb alloying also enhances the density-of-states near the valence band maximum for.a larger carrier effective mass, and suppresses the bipolar effect by increasing the carrier concentration and widening the band gap. Benefitting from both the.enhancement of power factor and the decrease of lattice thermal conductivity, the peak zT value is improved from ~ 0.45 at 573 K for Bi 2 Si 2 Te 6 to ~ 1.2 at 773 K for.BiSbSi 2 Te 6
