Blue-Light-Excitable Red-Emitting Organic Antimony Halides as a Reversible Humidity Sensor

Zero-dimensional organic antimony halides have attracted significant attention recently due to their structural variety, tunable optical properties, and high luminescence efficiency. Here, a new series of antimony bromide hybrid structures with seesaw [SbBr₄] and pyramidal [SbBr₅] geometries are reported with low band gaps and blue-light excited red emissions. Their luminescence is attributed to self-trapped excitons with a broadband emission of a large Stokes shift. Their photoluminescence signal is sensitive to water molecules, with a reversible positive correlation in a relative humidity range of 30-90%, enabling them as potential materials for real-time, self-consistent humidity sensors.