The effect of vacancy defects on the electromechanical properties of monolayer NiTe2 from first principles calculations

K H Yeoh; K-H Chew; Y H R Chang; T L Yoon; D S Ong

doi:10.1039/d2cp05102h

The effect of vacancy defects on the electromechanical properties of monolayer NiTe₂ from first principles calculations

Phys Chem Chem Phys. 2022 Dec 14;24(48):29952-29960. doi: 10.1039/d2cp05102h.

Authors

K H Yeoh^{1

2}, K-H Chew^{3

4}, Y H R Chang⁵, T L Yoon⁶, D S Ong⁷

Affiliations

¹ Department of Electrical and Electronic Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, 43000 Kajang, Selangor, Malaysia. khyeoh@utar.edu.my.
² Center for Photonics and Advanced Material Research, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, 43000 Kajang, Selangor, Malaysia.
³ Zhejiang Expo New Materials Co. Ltd., 1066, Xincheng Times Avenue, Longgang, Wenzhou 325802, China.
⁴ Key Laboratory of Optical Field Manipulation of Zhejiang Province, Department of Physics, Zhejiang Sci-Tech University, Hangzhou 310018, China.
⁵ Faculty of Applied Sciences, Universiti Teknologi MARA, Cawangan Sarawak, 94300 Samarahan, Sarawak, Malaysia. robincyh@uitm.edu.my.
⁶ School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia.
⁷ Faculty of Engineering, Multimedia University, Persiaran Multimedia, 63100 Cyberjaya, Selangor, Malaysia.

PMID: 36468660
DOI: 10.1039/d2cp05102h

Abstract

The electromechanical properties of monolayer 1-T NiTe₂ under charge actuation were investigated using first-principles density functional theory (DFT) calculations. Monolayer 1-T NiTe₂ in its pristine form has a work area density per cycle of up to 5.38 MJ m^-3 nm upon charge injection and it can generate a strain and a stress of 1.51% and 0.96 N m^-1, respectively. We found that defects in the form of vacancies can be exploited to modulate the electromechanical properties of this material. The presence of Ni-vacancies can further enhance the generated stress by 22.5%. On the other hand, with Te-vacancies, it is possible to improve the work area density per cycle by at least 145% and also to enhance the induced strain from 1.51% to 2.92%. The effect of charge polarity on the contraction and expansion of monolayer 1T-NiTe₂ was investigated. Due to its excellent environmental stability and good electromechanical properties, monolayer NiTe₂ is considered to be a promising electrode material for electroactive polymer (EAP) based actuators.