Tunable quantum gaps to decouple carrier and phonon transport leading to high-performance thermoelectrics

Yong Yu; Xiao Xu; Yan Wang; Baohai Jia; Shan Huang; Xiaobin Qiang; Bin Zhu; Peijian Lin; Binbin Jiang; Shixuan Liu; Xia Qi; Kefan Pan; Di Wu; Haizhou Lu; Michel Bosman; Stephen J Pennycook; Lin Xie; Jiaqing He

doi:10.1038/s41467-022-33330-9

Tunable quantum gaps to decouple carrier and phonon transport leading to high-performance thermoelectrics

Nat Commun. 2022 Sep 24;13(1):5612. doi: 10.1038/s41467-022-33330-9.

Authors

Yong Yu^#^{1

2}, Xiao Xu^#¹, Yan Wang^#¹, Baohai Jia¹, Shan Huang¹, Xiaobin Qiang¹, Bin Zhu¹, Peijian Lin¹, Binbin Jiang¹, Shixuan Liu¹, Xia Qi³, Kefan Pan¹, Di Wu³, Haizhou Lu¹, Michel Bosman², Stephen J Pennycook², Lin Xie⁴, Jiaqing He^{5

6}

Affiliations

¹ Shenzhen Key Laboratory of Thermoelectric Materials, Department of Physics, Southern University of Science and Technology, 518055, Shenzhen, China.
² Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore, Singapore.
³ School of Materials Science and Engineering, Shaanxi Normal University; Key Laboratory for Macromolecular Science of Shaanxi Province, 710062, Xi'an, China.
⁴ Shenzhen Key Laboratory of Thermoelectric Materials, Department of Physics, Southern University of Science and Technology, 518055, Shenzhen, China. xiel3@sustech.edu.cn.
⁵ Shenzhen Key Laboratory of Thermoelectric Materials, Department of Physics, Southern University of Science and Technology, 518055, Shenzhen, China. hejq@sustech.edu.cn.
⁶ Guangdong-Hong Kong-Macao Joint Laboratory for Photonic-Thermal-Electrical Energy Materials and Devices, Southern University of Science and Technology, 518055, Shenzhen, China. hejq@sustech.edu.cn.

^# Contributed equally.

Abstract

Thermoelectrics enable direct heat-to-electricity transformation, but their performance has so far been restricted by the closely coupled carrier and phonon transport. Here, we demonstrate that the quantum gaps, a class of planar defects characterized by nano-sized potential wells, can decouple carrier and phonon transport by selectively scattering phonons while allowing carriers to pass effectively. We choose the van der Waals gap in GeTe-based materials as a representative example of the quantum gap to illustrate the decoupling mechanism. The nano-sized potential well of the quantum gap in GeTe-based materials is directly visualized by in situ electron holography. Moreover, a more diffused distribution of quantum gaps results in further reduction of lattice thermal conductivity, which leads to a peak ZT of 2.6 at 673 K and an average ZT of 1.6 (323-723 K) in a GeTe system. The quantum gap can also be engineered into other thermoelectrics, which provides a general method for boosting their thermoelectric performance.