Optoelectronic properties, stability, and thermodynamic properties of 2D XSn2N4 (X = Cr, Mo, W) monolayers

Through first-principle calculations, we show innovative CrSn2N4, MoSn2N4 and WSn2N4 monolayers with high stability. The current results reveal that CrSn2N4 is a conductor-like material with metallic propensity, while MoSn2N4 and WSn2N4 are indirect bandgap semiconductors with narrow bandgaps of 0.16 eV and 0.39 eV, respectively. The mechanical characteristics of CrSn2N4, MoSn2N4, and WSn2N4 are stable, with Young's modulus and Poisson's ratio greater than those of graphene and C2F4. Besides, the thermodynamic characteristics were tested, and it was observed that the thermodynamic stability of MoSn2N4 was superior to the other two materials. The optical properties show the layered MoSn2N4 and WSn2N4 have strong light absorption and a wide absorption range, which have the potential for application in photovoltaic cells and devices. The spectral limits of the maximum efficiencies of 22% and 14% for MoSn2N4 and WSn2N4, respectively, are greater than those of SnO2. Thus, the three novel two-dimensional materials have potential applications in the area of photoelectric devices.