First-principles study on the electronic and optical properties of 2D chalcogenides M2X and M2X3 (M = Tl, in and X = O, S, Se)

Abstract Metal-shrouded two-dimensional (2D) semiconductors exhibit potential applications as sensors, catalysts, and energy storage devices due to their excellent electronic and mechanical properties. In this work, we investigated a series of 2D materials, that is, M2X and M2X3 (M = Tl, In and X = O, S, Se) chalcogenides, by using First-principles calculation based on density functional theory. We calculated the electronic and optical properties of these 2D materials. Results show that M2X chalcogenides, except 1T-In2O and 2H-In2O, are metal-shrouded 2D semiconductors. In addition, the absorption coefficients of M2X exhibited optical absorption over a wide wavelength range in the visible- and ultraviolet-light regions because of their moderate-sized bandgap. Such results provide theoretical basis for exploring the potential optoelectronic applications of metal-shrouded 2D semiconductors.