Superior self-charged and -powered chemical sensing with high performance for NO₂ detection at room temperature

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.