UV-Activated MoS₂ Based Fast and Reversible NO₂ 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 2 gas sensor at room temperature. The sensor’s performance is investigated to NO 2 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 2 exhibits an enhancement in sensitivity with ultrafast response time of ∼29 s and excellent recovery to NO 2 (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 2 /MoS 2 interaction under optical illumination. Moreover, the sensor shows reliable selectivity toward NO 2 against various other gases. These unprecedented results reveal the potential of 2D MoS 2 to develop a low power portable gas sensor.