Structural, electronic and optical properties of two-dimensional (M_2/3Y_1/3)₂CO₂ (M = Mo,W) iMXene

Abstract

Two-dimensional (2D) transition metal carbides and nitrides, known as MXenes, are continuously growing in terms of both crystalline and composition varieties. They have received significant attention in science and technology. The new members of MXenes with in-plane ordered double transition metals have been named as iMXenes. In this study, we have investigated the electronic structures and optical properties of 2D (Mo2/3Y1/3)2CO2 and (W2/3Y1/3)2CO2 iMXene monolayers, using a set of density functional theory calculations. We found that the (Mo2/3Y1/3)2CO2 and (W2/3Y1/3)2CO2 2CO2 are semiconductors with indirect bandgaps of 0.477 eV and 0.655 eV, respectively. To investigate the optical properties, we calculated the absorption spectrum and reflectivity percentage of these structures along x and z directions using the real and imaginary parts of the dielectric function. It is observed that the real and imaginary parts of their dielectric functions possess many peaks in the energy region of less than 3.1 eV. Interestingly, they show high absorption in the visible and UV regions, implying the potential applications of these semiconducting iMXenes in solar cells and optical nanodevices.

Recent Advances in Multidimensional (1D, 2D, and 3D) Composite Sensors Derived from MXene: Synthesis, Structure, Application, and Perspective

“…Three atomic structures have been discovered for the MXene family, respectively, M 2 X, M 3 X 2 , and M 4 X 3 , providing great possibility and tenability for exploring and exploiting diversiform materials according to particular demands. [80,81] Additionally, the MXene family have been expanded again with two new synthetic MXene subfamilies in recent years, the ordered double-transition metal MXene, respectively M′ 2 M″C 2 and M′ 2 M″ 2 C 3 , where M′ and M″ are two different early transition metals. [82] Up to now, nearly thirty kinds of MXene have been fabricated successfully, including synthetic Ti 3 C 2 , Ti 2 C, Ti 3 CN, Ta4C3, Nb 2 C, V 2 C, (Ti 0.5 Nb 0.5 ) 2 C, and (V 0.5 Cr 0.5 ) 3 C 2 .…”

Electronic Structures of Group III–V Element Haeckelite Compounds: A Novel Family of Semiconductors, Dirac Semimetals, and Topological Insulators

“…The synthesis and theory of 2D materials (2Ds), for example, graphene, [1] MoS 2 , [2] phosphorene, [3] transition metal carbides, and nitrides (MXenes), [4][5][6][7][8][9] and transition metal borides [10][11][12][13] have entailed a significant boosting of the science and technology at the nanoscale. [14][15][16][17][18][19] The 2Ds have become the main playground for various emergent Dirac-based phenomena such as Dirac fermions, [20] topological insulators, [21][22][23][24] Weyl semimetals, [25] nodal line semimetals, [26] etc. [27] Most of the above 2Ds are derived from 3D bulk structures.…”

A tight-binding model for the electronic structure of MXene monolayers

“…As a prominent application, MXene semiconductors might be useful for optical devices. [13][14][15] The results of DFT calculations can make significant predictions for experimental researchers for accurate guidance in understanding their structural and electronic properties. Previous studies indicated that 2D InO is a stable 2D metal oxide whose structure is optimized by DFT calculations.…”