Superior Self‐Charged and ‐Powered Chemical Sensing with High Performance for NO₂ Detection at Room Temperature

Abstract Halide based lead perovskites are recently being explored as efficient light harvesters for optoelectronics devices. Here, some new insights on the self‐charging and energy‐storage of triple cation FA_0.80MA_0.15Cs_0.05PbI_2.55Br_0.45 (FMCPIB) perovskites based devices with the application for self‐powered chemical sensing are presented. It is demonstrated that under light irradiation a self‐powered FMCPIB based device can detect particle per million (ppm) concentrations of nitrogen dioxide (NO₂) with a swift response and recovery time of ≈17 and ≈126 s at room temperature, respectively. Most notably, the energy‐storage feature enables FMCPIB based devices like a photo‐capacitor, and then remain operational for another 1.7 h in darkness for the detection of NO₂ without external power supply. Besides, the FMCPIB based devices can also be operated with a 1 V bias achieving a detection limit 0.2 ppm of NO₂ at room temperature. Through analysis, it reveals that the high performance for NO₂ can be ascribed to the special NO₂‐amine interaction with the cations of FMCPIB and the storage capacitance might be due to the accumulation of charges at the TiO₂/FMCPIB/carbon interfaces under light irradiation. These appealing features of FMCPIB perovskites based chemical sensors might find potential applications in monitoring of toxic gas emission and public space safety.