First-principles calculations of optical properties of 2D CaFBr and BaFBr monolayers

Advanced works have been significantly committed to the progression of next-generation optoelectronic plans based on 2D materials, due to their novel optical properties that are distinctive from those of 3D materials. In this Way, we apply the generalized gradient approximation in the framework of density functional theory to examine the optical properties of 2D halide XFBr (where X = Ba or Ca), such as absorption, conductivity, refractive index, and dielectric function. According to our DFT–PBE calculations, the static dielectric constants of BaFBr and CaFBr are 1.40 and 1.50, respectively, which can be used as a good dielectric material since materials with high dielectric constants are helpful in the fabrication of high-value capacitors. The reflectivity index spectrum for each layer reveals that the reflectivity is crucial in the visible–ultraviolet area up to 25 eV, showing that it has potential as a wonderful sheet material. •We investigate the optical properties of 2D BaFBr and CaFBr monolayers.•The static dielectric constants of BaFBr and CaFBr are 1.40 and 1.50, respectively.•The absorption coefficient spectra explain the semiconductors nature of these monolayers.•These sheets show a good absorption coefficient in the 10–20 eV region.