Novel thermoelectric performance of 2D 1T- Se2Te and SeTe2with ultralow lattice thermal conductivity but high carrier mobility

ShaoBo Chen; Wang-Li Tao; Yu Zhou; Zhao-Yi Zeng; Xiang-Rong Chen; Hua-Yun Geng

doi:10.1088/1361-6528/ac1a91

Novel thermoelectric performance of 2D 1T- Se₂Te and SeTe₂with ultralow lattice thermal conductivity but high carrier mobility

Nanotechnology. 2021 Aug 19;32(45). doi: 10.1088/1361-6528/ac1a91.

Authors

ShaoBo Chen^{1

2}, Wang-Li Tao¹, Yu Zhou¹, Zhao-Yi Zeng³, Xiang-Rong Chen¹, Hua-Yun Geng⁴

Affiliations

¹ Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, People's Republic of China.
² College of Electronic and Information Engineering, Anshun University, Anshun 561000, People's Republic of China.
³ College of Physics and Electronic Engineering, Chongqing Normal University, Chongqing 400047, People's Republic of China.
⁴ National Key Laboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, CAEP, Mianyang 621900, People's Republic of China.

PMID: 34348253
DOI: 10.1088/1361-6528/ac1a91

Abstract

The design and search for efficient thermoelectric materials that can directly convert waste heat into electricity have been of great interest in recent years since they have practical applications in overcoming the challenges of global warming and the energy crisis. In this work, two new two-dimensional 1T-phase group-VI binary compounds Se₂Te and SeTe₂with outstanding thermoelectric performances are predicted using first-principles calculations combined with Boltzmann transport theory. The dynamic stability is confirmed based on phonon dispersion. It is found that the spin-orbit coupling effect has a significant impact on the band structure of SeTe₂, and induces a transformation from indirect to direct band gap. The electronic and phononic transport properties of the Se₂Te and SeTe₂monolayer are calculated and discussed. High carrier mobility (up to 3744.321 and 2295.413 cm²V^-1S^-1for electron and hole, respectively) is exhibited, suggesting great applications in nanoelectronic devices. Furthermore, the maximum thermoelectric figure of meritzTof SeTe₂for n-type and p-type is 2.88, 1.99 and 5.94, 3.60 at 300 K and 600 K, respectively, which is larger than that of most reported 2D thermoelectric materials. The surprising thermoelectric properties arise from the ultralow lattice thermal conductivityk_l(0.25 and 1.89 W m^-1K^-1for SeTe₂and Se₂Te at 300 K), and the origin of ultralow lattice thermal conductivity is revealed. The present results suggest that 1T-phase Se₂Te and SeTe₂monolayer are promising candidates for thermoelectric applications.

Keywords: 1T-phase; 2D material; thermal conductivity; thermoelectricity.