Theoretical investigation of the optical and electronic properties of surface engineered V ₂ N MXene

Abstract

In this work, density functional theory is utilized to explore the impact of surface adsorption of (O, S, Se and Te) on the structural, electronic and optical properties of two-dimensional vanadium nitride (V2N) MXene and the results are compared with pristine V2N MXene. Our calculations show that V2NSe2 MXene has the most stable structure among all the studied structures. Adsorption energy computations reveal that all terminal groups on the surface of the pristine V2N tightly attach to the V atoms. A metallic to semiconductor transition is observed in all the considered V2NT2 (T= O, S, Se and Te) MXene structures. Among them, oxygen, selenium and tellurium adsorbed V2N shows a direct bandgap of 0.45, 0.86 and 0.53 eV, respectively. However, in case of sulphur adsorbed V2N MXene, an indirect bandgap of 1.19 eV is observed. This study also reports the effect of surface adsorption on the optical properties and dielectric of V2NT2 (T= O, S, Se and Te). The results reveal a larger absorption in visible region as well as in ultraviolet region for all the computed structures except oxygen adsorbed V2N MXene as compared to pristine V2N MXene monolayer, which indicates the significance of surface adsorption on the optical properties of the studied MXene. Additionally, a very low reflectivity has been seen in all the V2NT2 MXene structures as compared to pristine V2N . Our findings demonstrate the potential of these surface adsorbed V2N MXene materials in novel light-electron conversion devices.