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High-Temperature Thermoelectric Monolayer Bi2TeSe2 with High Power Factor and Ultralow Thermal Conductivity
ACS Applied Energy Materials ( IF 5.4 ) Pub Date : 2022-02-17 , DOI: 10.1021/acsaem.1c04109
Ning Wang 1 , Chen Shen 2 , Zhehao Sun 3 , Haiyan Xiao 1 , Hongbin Zhang 2 , Zongyou Yin 3 , Liang Qiao 1
Affiliation  

Because of the quantum confinement effect and the interface/surface effect, the band gap of 0.8–1.5 eV for two-dimensional (2D) bismuth-based material is significantly enlarged relative to that of bulk phase materials (∼0.2 eV), which removes the inhibition effect caused by bipolar transport for the Seebeck coefficients of bulk-phase bismuth-based materials at high temperature. Therefore, the 2D bismuth-based materials exhibit huge application prospects in high-temperature thermoelectric (TE) devices, whereas their figure of merits (ZT) need to be further improved. This work reports the thermal and electrical transport properties of 2D Bi2TeSe2, a new Janus Bi2Te3-based material, from the first-principles calculations. Compared with Bi2Se3/Bi2Te3 monolayers and corresponding Janus materials, the Bi2TeSe2 monolayer exhibits a much lower lattice thermal conductivity (κ) of 0.27 W/mK at 900 K because of stronger phonon anharmonicity and higher frequency phonon scattering. In addition, because the energy pockets around the valence band maximum show convergence character, the Seebeck coefficient (SC) of the p-type system is effectively enhanced. Combined with its intrinsic high electron transport properties, a high power factor of 3.48 mW/mK2 at 900 K is obtained for the p-type Bi2TeSe2 monolayer. The ultralow κ and enhanced SC of the Bi2TeSe2 monolayer eventually result in a significant optimal ZT value of 3.45 at 900 K. Thus, our study provides insights into the thermoelectric properties of the Bi2TeSe2 monolayer and may open up an effective avenue for applying bismuth-based materials to a high-temperature TE field.

中文翻译:

具有高功率因数和超低热导率的高温热电单层 Bi2TeSe2

由于量子限制效应和界面/表面效应,二维(2D)铋基材料的带隙为 0.8-1.5 eV 相对于体相材料(~0.2 eV)显着扩大,这消除了双极输运对体相铋基材料在高温下的塞贝克系数的抑制作用。因此,二维铋基材料在高温热电(TE)器件中展现出巨大的应用前景,而其品质因数(ZT)有待进一步提高。这项工作报告了 2D Bi 2 TeSe 2的热和电传输特性,这是一种新的 Janus Bi 2 Te 3- 基于材料,从第一性原理计算。与 Bi 2 Se 3 /Bi 2 Te 3单层和相应的 Janus 材料相比,Bi 2 TeSe 2单层在 900 K 时的晶格热导率 (κ) 低得多,为 0.27 W/mK,因为声子非谐性更强且声子频率更高散射。此外,由于价带最大值附近的能量袋表现出收敛性,p型系统的塞贝克系数(SC)得到有效增强。结合其固有的高电子传输特性,对于 p 型 Bi 2 TeSe ,在 900 K 时获得了 3.48 mW/mK 2的高功率因数2单层。Bi 2 TeSe 2单层的超低 κ 和增强的 SC最终导致在 900 K 时显着的最佳ZT值为 3.45。因此,我们的研究提供了对 Bi 2 TeSe 2单层的热电性质的见解,并可能开辟一种有效的方法。将铋基材料应用于高温 TE 场的途径。
更新日期:2022-02-17
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