Nondestructive functionalization of monolayer black phosphorus using Lewis acids: A first-principles study

Functionalization of layered black phosphorus is valuable for engineering its chemical properties and enhancing the chemical stability. Here we report density functional theory calculations, through which we show that the phosphorus surface can be decorated by a few Lewis acids with stable interfacial binding, which preserves the band gap of monolayer black phosphorus with tunable band edge energies. The strong interfacial binding is mediated by a Lewis acid-base chemistry between the lone pair electrons in phosphorous and the electron accepting Lewis acids. We further show that magnetic moment can be introduced into phosphorus using the Lewis acids such as FeCl₃. Furthermore, the surface modification can be responsive using the acylation chemistry. Our work thus shows that the chemical stability and electronic properties of black phosphorus can be finely tuned because of its rich chemistry.