Uniaxial strain engineering of the electronic and optical properties of phenyl-functionalized black phosphorus

•Covalent functionalization of phenyl resulted in a semiconductor–metal transition for black phosphorus.•Strains applied along the armchair direction restored the phenyl-functionalized black phosphorus to a p-type semiconductor.•It existed prominent bonding states between the interlayer broken P atoms under tensile strain.•The compressive strain heightened the adsorption capacity and reflectivity of phenyl-functionalized black phosphorus in high-energy regions.