High-Performance Gas Sensor Using a Large-Area WSSe Alloy for Low-Power Operation Wearable Applications.

Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) have attracted considerable attention as promising building blocks for a new generation of gas-sensing devices because of their excellent electrical properties, superior response, flexibility, and low-power consumption. Owing to their large surface-to-volume ratio, various 2D TMDCs, such as MoS, MoSe, WS, and WSe, have exhibited excellent gas-sensing characteristics. However, exploration toward the enhancement of TMDC gas-sensing performance has not yet been intensively addressed. Here, we synthesized large-area uniform WSSe alloys for room-temperature gas sensors. As-synthesized WSSe alloys exhibit an elaborative composition control owing to their thermodynamically stable sulfurization process. Further, utilizing uniform WSSe alloys over a large area, we demonstrated improved NO-sensing performance compared to WSe on the basis of an electronic sensitization mechanism. The WSSe alloy gas sensor exhibits 2.4 times enhanced response for NO exposure. Further, we demonstrated a low-power wearable NO-detecting wristband that operates at room temperature. Our results show that the proposed method is a promising strategy to improve 2D TMDC gas sensors and has a potential for applications in advanced gas-sensing devices.