The CH3NH3PbI3 (MAPbI3) powders were ground by PbI2 and CH3NH3I prepared by ice bath method. The humidity sensitive properties of an impedance-type sensor based on MAPbI3 materials were systematically studied. Our results indicate that the MAPbI3-based sensor has superior sensing behaviors, including high sensitivity of 5808, low hysteresis, approximately 6.76%, as well as good stability. Water-molecule-induced enhancement of the conductive carrier concentration was argued to be responsible for the excellent humidity sensitive properties. Interestingly, the humidity properties can be affected by red light sources. The photogenerated carriers broke the original balance and decreased the impedance of the sensor. This work promotes the development of perovskite materials in the field of humidity sensing.
Keywords: humidity sensing; impedance-type sensors; organometallic halide perovskite.