Graphene-based chemiresistive hydrogen sensor for room temperature operation

Taking advantage of ultraviolet (UV) irradiation to clean the surface and tuning the charge carriers of graphene, n-doped graphene shows excellent hydrogen sensing capabilities. With assistance of a 265 nm UV light irradiation, the response time of sensor reaches 3 s to 5 ppm hydrogen. And after being relented in ambient condition for a year, it still maintains nearly identical performance. Furthermore, by adding PMMA layer as molecular sieve, the sensor can effectively shield against humidity changes, exhibiting high selectivity towards hydrogen. When the relative humidity varies within the range in 20-70 %, the sensor basically maintains similar response performance. This work streamlines the preparation process of hydrogen sensors and introducing exceptional selectivity with the help of a molecular sieve, facilitating the practical application of hydrogen sensors.