Generating strong room-temperature photoluminescence in black phosphorus using organic molecules

Black phosphorus (BP) exhibits fascinating thickness dependent optical and electronic characteristics. However, photoluminescence (PL) emission in the visible spectrum does not exist for multilayer BP and requires the achievement of single layer, which are highly environmentally sensitive. This poses significant challenges in realizing the true potential of BP as multilayer BP exhibits exciting optical properties for a range of applications. Here, for the first time we reveal visible range room-temperature photoluminescence (PL) in multi-layered black phosphorus (BP) via chemical doping using organic molecules. We find the drastic enhancement of PL originates from the adsorption of p-type dopants and offer further insight using density functional theory (DFT) calculations. The reported non-destructive method creates a pathway to precisely control optical and electronic properties thereby expanding the application horizon for multilayer BP that is environmentally robust compared to monolayer.