UV-Activated MoS Based Fast and Reversible NO Sensor at Room Temperature.

Two-dimensional materials have gained considerable attention in chemical sensing owing to their naturally high surface-to-volume ratio. However, the poor response time and incomplete recovery at room temperature restrict their application in high-performance practical gas sensors. Herein, we demonstrate ultrafast detection and reversible MoS gas sensor at room temperature. The sensor's performance is investigated to NO at room temperature, under thermal and photo energy. Incomplete recovery and high response time of ∼249 s of sensor are observed at room temperature. Thermal energy is enough to complete recovery, but it is at the expense of sensitivity. Further, under photo excitation, MoS exhibits an enhancement in sensitivity with ultrafast response time of ∼29 s and excellent recovery to NO (100 ppm) at room temperature. This significant improvement in sensitivity (∼30%) and response time (∼88%) is attributed to the charge perturbation on the surface of the sensing layer in the context of NO/MoS interaction under optical illumination. Moreover, the sensor shows reliable selectivity toward NO against various other gases. These unprecedented results reveal the potential of 2D MoS to develop a low power portable gas sensor.