Extended Data Fig. 1: Schematic of PNR production.
Black phosphorus crystals were outgassed in a fused silica reaction tube, and lithium metal was added. The tube was cooled to −50 °C and high-purity ammonia (NH3) was condensed onto the black phosphorus and lithium, dissolving the alkali metal to form a Li:NH3 solution. The black phosphorus was left submerged in the Li:NH3 solution for about 24 hours, allowing intercalation, before the ammonia was slowly removed. Without air exposure, the intercalated black phosphorus crystal was transferred to a glovebox and placed into a vial, and NMP was added. This vial was then placed in an ultrasonic bath for 1 hour and centrifuged at low acceleration. This process resulted in solutions of phosphorene nanoribbons.
