Few-layer ultrathin nanosheets and ultrasmall quantum dots of black phosphorus (BP) have attracted increasing research interest due to their fascinating properties including a tunable bandgap, high carrier mobility, and ambipolar conduction ability. These excellent properties together with their unique structures make BP derivatives promising candidates for a wide range of device applications. In this research news, the latest advancements in the synthesis, properties, and applications of BP and its derivatives are highlighted. In particular, the focus is on the use of these rising star materials for emerging solar cells, in terms of both theoretical predictions and experimental investigations. Finally, the authors' personal perspectives on potential future research directions are provided.