摘要
Utilization of light to boost the performance of gas sensors allows us to operate sensor devices at room temperature. Here, we, for the first time, demonstrated an indoor light-activated 3D cone-shaped MoS 2 bilayer-based NO gas sensor with ppb-level detection operated at room-temperature. Large-area cone-shaped (CS)-MoS 2 bilayers were grown by depositing 2 nm-thick MoO 3 layers on a 2′′ three-dimensional (3D) cone-patterned sapphire substrate (CPSS) followed by a sulfurization process via chemical vapor deposition. Because the exposed area of MoS 2 bilayers is increased by 30%, the CS-MoS 2 gas sensor (GS) demonstrated excellent performance with a response of ∼470% and a fast response time of ∼25 s after exposure to 1 ppm of NO gas illuminated by ultraviolet (UV) light with a wavelength of 365 nm. Such extraordinary performance at room temperature is attributed to the enhanced light absorption because of the light scattering effect caused by the 3D configuration and photo-desorption induced by UV illumination. For NO concentrations ranging from 2 ppm down to 0.06 ppm, the CS-MoS 2 GS demonstrated a stable sensing behavior with a high response and fast response time (470% and 25 s at 2 ppm NO) because of the light absorption enhanced by the 3D structure and photo-desorption under constant UV illumination. The CS-MoS 2 GS exhibits a high sensitivity (∼189.2 R% ppm -1 ), allowing the detection of NO gas at 0.06 ppm in 130 s. In addition, the 3D cone-shaped structure prolonged the presence of sulfur vapor around MoO 3 , allowing MoO 3 to react with sulfur completely. Furthermore, the CS-MoS 2 GS using an indoor lighting to detect NO gas at room temperature was demonstrated for the first time where the CS-MoS 2 GS exhibits a stable cycling behavior with a high response (165% at 1 ppm NO) in 50 s; for concentration as low as ∼0.06 ppm, the response of ∼75% in 150 s can be achieved.