Single and few layer sheets of black phosphorus (BP) represent a new class of non-carbon 2D materials. Like graphite/graphene, black phosphorus represents an allotrope of an element consisting of one atom type only. Black phosphorus has a couple of outstanding physical properties which renders it ideal for its implementation in high-tech applications in the fields of molecular electronics, solar cells, gas sensors, and lithium ion batteries. A major hurdle, which had to be overcome, was the access to single layer BP in order to investigate its physical and chemical properties in detail. At the beginning of B-PhosphoChem, the scientific research was predominantly focused on the experimental and theoretical investigation of the physical and materials properties of BP, the chemistry of this novel 2D material, however, remained almost unexplored. At this point, B PhosphoChem set in: it was the first coordinated project to systematically explore and develop the methodologies to access and stabilize single and few-layer BP and simultaneously investigate its chemistry and characterization. In the course of B-PhosphoChem we were able to exfoliate BP down to single monolayers, to understand the degradation of the material and to develop solutions for its stabilization, to tailor the non-covalent chemistry of BP and to use specific functional dye molecules for its implementation into field effect transistors, to intercalate crystalline BP with alkali metals in order to activate the layered material for a subsequent exfoliation/covalent functionalization sequence, to propel the characterization of BP and its derivatives by means of Raman spectroscopy, and to proof the concept that BP can be utilized as molecular catalyst. The results obtained by our detailed scientific research of the chemistry of BP can serve as the corner stone for technological applications of this novel 2D material.
