Degradation of Black Phosphorus and Strategies to Enhance Its Ambient Lifetime

Exfoliation of black phosphorus (BP) into phosphorene has led to the discovery of its semiconducting properties and tunable bandgap, enabling its use in a range of applications including transistors, batteries, and sensors. However, BP's ambient instability poses a considerable challenge to its incorporation into functional devices. Observed changes to the surface chemistry of BP during degradation has recently provided insight into the degradation pathways. In this review, degradation mechanisms are discussed including the effect of oxidants, such as oxygen, water, and light, on BP degradation. Additionally, a comprehensive overview on the progress made in characterizing the surface chemistry of BP is provided, as well as the methods employed to enhance its ambient stability including capping layers, covalent and noncovalent functionalization, solvent passivation, and polymer-based protection strategies. The effect of various protection strategies on the ambient lifetime of BP and their influence on the properties of BP are discussed.