A self-powered flexible gas-sensing system based on single-wall carbon nanotube films

Abstract

Flexible self-powered sensors are attracting increasing research interest with the emergence and rapid development of the Internet of Things. However, inefficient power supplies and difficulties in device assembly have largely limited their applications. Here, we report an integrated gas-sensing system using a single-walled carbon nanotube film with good flexibility and large surface area to detect a target gas. A single-walled carbon nanotube/silicon heterojunction solar cell capable of stably providing a voltage of ∼0.5 V under the illumination of a standard solar intensity powers the sensor. Our self-powered sensing system shows an ideal rectangle-shaped nitrogen dioxide detection curve and demonstrates higher sensitivity and faster response time than one driven by external power at room temperature. We attribute this better activity to the increased carrier concentration originating from single-walled carbon nanotubes in both sensing and powering components. Finally, wireless communication between the system and a phone is demonstrated with a Bluetooth Low Energy module.