First-principles quantum computational study to investigate radiation energy-dependent effect on optoelectronic properties of bismuth oxyhalides BiOX (X= I, Br)

Metal oxyhalides are potential candidates for fundamental and technological interest in pharmaceutical, biological, optical, photoluminance, sensing, energy, and photocatalyst applications. In this article, using first-principles density functional quantum computational approach, we investigate the electronic and optical properties of two members of bismuth oxyhalides, BiOX (X=I, Br). The study is mainly aimed to characterize and examine the radiation energy-dependent optical properties of the compounds by using mBJ approximation with full potential linearized augmented plane wave method. The oxyhalides show indirect bandgap semiconductor nature having bandgaps of 2.2 eV for BiOI and 3.5 eV for BiOBr. Besides, these are p-type materials owing to large hole-like carrier density of states in valence bands close to the Fermi level. The energy bands show considerable dispersion of particles. The increasing reflectivity at high energy shows potential of the materials as good reflector in shielding screens or glasses to avoid damage form ultraviolet radiation.