An ultrasensitive and reversible fluorescence sensor of humidity using perovskite CH3NH3PbBr3

An organic–inorganic hybrid fluorescent perovskite, CH3NH3PbBr3, was synthesized by a grinding method, and applied for humidity sensing. Its strong fluorescence at 530 nm could be linearly quenched by a humidity increase from 7 to 98%. Coupled with a red-emitting reference dye, 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin, a colorimetric humidity sensor was produced using the perovskite. The sensor appeared to be sensitive to increased humidity by displaying a color change from green to red, or vice versa, with good reversibility. The proposed approach should provide a new strategy in the design of sensitive and applicable humidity sensors.