Band Engineering of SnSe ₂ via Ag‐Doping Enables Rapid NO ₂ Sensors at Room Temperature

SnSe 2 , as a typical main‐group metal dichalcogenide, has been widely investigated for electronic devices such as gas sensors. However, the SnSe 2 sensors still face challenges including low and sluggish response when detecting gases at room temperature (RT). In this work, we report a strategy that utilize Ag atoms to alter the electronic structure of SnSe 2 to achieve rapid detection of NO 2 at RT. The experiments show that the Ag‐SnSe 2 sensor has a very fast response to NO 2 with a detection limit down to 50 ppb. Density functional theory simulations further reveals that the introduction of Ag significantly changed the band structure and electronic properties of SnSe 2 , thereby improving the adsorption and interaction with NO 2 through orbital hybridization. This work provides an efficient strategy to engineer the electronic properties of 2D sensors.