A general strategy for designing two-dimensional high-efficiency layered thermoelectric materials. Issue 7 (8th June 2021)

• Record Type: Journal Article
• Authors: Zhang, Xiwen; Guo, Yilv; Zhou, Zhaobo; Li, Yunhai; Chen, Yunfei; Wang, Jinlan
• Is Part Of: Energy & environmental science. Volume 14:Issue 7(2021)
• Page Start: 4059
• Page End: 4066
• Publication Date: 2021-06-08
• Subjects: Energy conversion -- Periodicals; Fuel switching -- Periodicals; Environmental sciences -- Periodicals; Environmental chemistry -- Periodicals; 333.79
• DOI: 10.1039/d1ee00356a
• Languages: English
• ISSNs: 1754-5692

Abstract

Abstract : Introducing lone pairs occupied in the p z -orbital not only effectively improves the electronic transport properties, but also increases low-frequency and high-frequency phonon scattering simultaneously. Abstract : 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, BiBi2 X3 (X = S/Se/Te), are successfully predicted, which are obtained through inserting Bi ML into the vdW gap of a Bi2 X3 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 BiBi2 X3 exhibits an ultrahigh ZT (2.12 for 2D BiBi2 Te2 S around room-temperature). The design strategy and the ultrahigh 2D ZT are of vital importance for advanced TE technology.