TY - JOUR

T1 - Highly anisotropic mechanical and optical properties of 2D NbOX2 (X= Cl, Br, I) revealed by first-principle

AU - Mortazavi, Bohayra

AU - Shahrokhi, Masoud

AU - Javvaji, Brahmanandam

AU - Shapeev, Alexander V

AU - Zhuang, Xiaoying

N1 - Funding Information: B M and X Z appreciate the funding by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy within the Cluster of Excellence PhoenixD (EXC 2122, Project ID 390833453). The authors also acknowledge the support of the cluster system team at the Leibniz Universität of Hannover. B M is greatly thankful to the VEGAS cluster at Bauhaus University of Weimar for providing the computational resources. A V S is supported by the Russian Science Foundation (Grant No 18-13-00479, https://rscf.ru/project/18–13–00479/ ).

PY - 2022/4/12

Y1 - 2022/4/12

N2 - In the latest experimental success, NbOI2two-dimensional (2D) crystals with anisotropic electronic and optical properties have been fabricated (Adv. Mater.33 (2021), 2101505). In this work inspired by the aforementioned accomplishment, we conduct first-principles calculations to explore the mechanical, electronic, and optical properties of NbOX2(X = Cl, Br, I) nanosheets. We show that individual layers in these systems are weakly bonded, with exfoliation energies of 0.22, 0.23, and 0.24 J m-2, for the isolation of the NbOCl2, NbOBr2,and NbOI2monolayers, respectively, distinctly lower than those of the graphene. The optoelectronic properties of the single-layer, bilayer, and bulk NbOCl2, NbOBr2,and NbOI2crystals are investigated via density functional theory calculations with the HSE06 approach. Our results indicate that the layered bulk NbOCl2, NbOBr2,and NbOI2crystals are indirect gap semiconductors, with band gaps of 1.79, 1.69, and 1.60 eV, respectively. We found a slight increase in the electronic gap for the monolayer and bilayer systems due to electron confinement at the nanoscale. Our results show that the monolayer and bilayer of these novel 2D compounds show suitable valence and conduction band edge positions for visible-light-driven water splitting reactions. The first absorption peaks of these novel monolayers along the in-plane polarization are located in the visible range of light which can be a promising feature to design advanced nanoelectronics. We found that the studied 2D systems exhibit highly anisotropic mechanical and optical properties. The presented first-principles results provide a comprehensive vision about direction-dependent mechanical and optical properties of NbOX2(X = Cl, Br, I) nanosheets.

AB - In the latest experimental success, NbOI2two-dimensional (2D) crystals with anisotropic electronic and optical properties have been fabricated (Adv. Mater.33 (2021), 2101505). In this work inspired by the aforementioned accomplishment, we conduct first-principles calculations to explore the mechanical, electronic, and optical properties of NbOX2(X = Cl, Br, I) nanosheets. We show that individual layers in these systems are weakly bonded, with exfoliation energies of 0.22, 0.23, and 0.24 J m-2, for the isolation of the NbOCl2, NbOBr2,and NbOI2monolayers, respectively, distinctly lower than those of the graphene. The optoelectronic properties of the single-layer, bilayer, and bulk NbOCl2, NbOBr2,and NbOI2crystals are investigated via density functional theory calculations with the HSE06 approach. Our results indicate that the layered bulk NbOCl2, NbOBr2,and NbOI2crystals are indirect gap semiconductors, with band gaps of 1.79, 1.69, and 1.60 eV, respectively. We found a slight increase in the electronic gap for the monolayer and bilayer systems due to electron confinement at the nanoscale. Our results show that the monolayer and bilayer of these novel 2D compounds show suitable valence and conduction band edge positions for visible-light-driven water splitting reactions. The first absorption peaks of these novel monolayers along the in-plane polarization are located in the visible range of light which can be a promising feature to design advanced nanoelectronics. We found that the studied 2D systems exhibit highly anisotropic mechanical and optical properties. The presented first-principles results provide a comprehensive vision about direction-dependent mechanical and optical properties of NbOX2(X = Cl, Br, I) nanosheets.

KW - 2D NbOI2

KW - anisotropic

KW - mechanical

KW - optical

KW - photocatalysis

KW - semiconductor

KW - 2D NbOI

UR - http://www.scopus.com/inward/record.url?scp=85128487887&partnerID=8YFLogxK

U2 - 10.1088/1361-6528/ac622f

DO - 10.1088/1361-6528/ac622f

M3 - Article

VL - 33

JO - NANOTECHNOLOGY

JF - NANOTECHNOLOGY

SN - 0957-4484

IS - 27

M1 - 275701

ER -