A general strategy for designing two-dimensional high-efficiency layered thermoelectric materials,Energy & Environmental Science

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A general strategy for designing two-dimensional high-efficiency layered thermoelectric materials
Energy & Environmental Science ( IF 32.4 ) Pub Date : 2021-5-15 , DOI: 10.1039/d1ee00356a
Xiwen Zhang _{1,

2,

3,

4} , Yilv Guo _{2,

3,

4,

5} , Zhaobo Zhou _{2,

3,

4,

5} , Yunhai Li _{2,

3,

4,

5} , Yunfei Chen _{1,

2,

3,

4} , Jinlan Wang _{1,

2,

3,

4}

Affiliation

Two-dimensional (2D) thermoelectrics (TEs) with a high figure of merit (ZT > 2) are the core of the development of advanced energy technology. However, such a high ZT has rarely been realized in nanoscale thermoelectric (TE) systems, and advanced improvement theories and strategies are also absent. Here we propose a general design strategy, i.e., introducing an atom-thickness monolayer (ML) with p_z-orbital occupied lone pairs into the van der Waals (vdW) gap of layered materials to enhance the ZT. As an example, a new class of 2D room-temperature TE materials, BiBi₂X₃ (X = S/Se/Te), are successfully predicted, which are obtained through inserting Bi ML into the vdW gap of a Bi₂X₃ bilayer (BL). The inserted Bi ML, on one hand, brings high electronic density of states [g(E)] and sharp increase in g(E) near the Fermi level and therefore produces a large power factor. On the other hand, it achieves individually suppressed low-frequency and high-frequency related phonon transport through introducing local collective vibration modes and sensitive electrostatic interaction. As a result, 2D BiBi₂X₃ exhibits an ultrahigh ZT (2.12 for 2D BiBi₂Te₂S around room-temperature). The design strategy and the ultrahigh 2D ZT are of vital importance for advanced TE technology.

中文翻译：

设计二维高效层状热电材料的一般策略

具有高品质因数 ( ZT > 2)的二维 (2D) 热电 (TE)是先进能源技术发展的核心。然而，如此高的ZT在纳米级热电 (TE) 系统中很少实现，也缺乏先进的改进理论和策略。在这里，我们提出了一种通用的设计策略，即，将具有 p _z轨道占据孤对的原子厚度单层 (ML)引入到层状材料的范德华 (vdW) 间隙中以增强ZT。例如，一类新的二维室温 TE 材料 BiBi ₂ X ₃(X = S/Se/Te) 被成功预测，这是通过将 Bi ML 插入 Bi ₂ X ₃双层 (BL)的 vdW 间隙中获得的。一方面，插入的 Bi ML 带来了高电子态密度 [ g ( E )] 和费米能级附近g ( E ) 的急剧增加，因此产生了很大的功率因数。另一方面，它通过引入局部集体振动模式和敏感的静电相互作用来实现单独抑制的低频和高频相关声子传输。因此，2D BiBi ₂ X ₃表现出超高的ZT（2D BiBi ₂ Te为 2.12₂ S 大约室温）。设计策略和超高二维ZT对于先进的 TE 技术至关重要。

更新日期：2021-06-08

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