Ultrasensitive detection of hydrogen sulfide gas based on perovskite vertical channel chemo-sensor

An ultrasensitive hydrogen sulfide gas sensor based on methylammonium lead perovskite is reported in this work. The pseudohalide molecular anion (SCN-) was introduced as a dopant in the perovskite-based active layer of the sensor. With the enlarged operational current provided by the vertical structure of the sensors, both the MAPbI(3-x)(SCN)(x)-based and the MAPbI(3)-based gas sensors exhibit excellent ppb-regime (similar to 200 ppb) hydrogen sulfide gas sensing capability. Particularly, with the SCN- doped, the MAPbI(3-x)(SCN)(x)-based gas sensor demonstrates an enhanced sensitivity and a much improved ambient air endurance by extending the device lifetime more than 5 days. Finally, we also conducted experiments to study the effects of relative humidity and light irradiation on sensing performance. Preliminary mechanisms were also proposed.