Room-Temperature\nFlexible CNT/Fe<sub>2</sub>O<sub>3</sub> Film Sensor for ppb-Level\nH<sub>2</sub>S Detection

Carbon nanotubes (CNTs) had room temperature response,\nlarge surface\narea, and excellent mechanical properties, making them favorable for\nthe design of flexible, wearable, and portable gas sensors. However,\nCNTs were lacking in response and selective response to different\ngases, such as H<sub>2</sub>S. Here, we demonstrated a flexible H<sub>2</sub>S ppb-level gas sensor based on a carbon nanotube/amorphous\nFe<sub>2</sub>O<sub>3</sub> (CNT/Fe<sub>2</sub>O<sub>3</sub>) film\nat room temperature, which was fabricated via a simple one-step solvent-thermal\nmethod. The CNT/Fe<sub>2</sub>O<sub>3</sub> film gas sensor exhibited\na high selective response to H<sub>2</sub>S (with a response of 55.1%\nto 100 ppb H<sub>2</sub>S), rapid reversible response at room temperature\n(with a response time of ∼127 s to 100 ppb H<sub>2</sub>S),\nand low limit of detection to about 2 ppb. Additionally, the CNT/Fe<sub>2</sub>O<sub>3</sub> film maintained good sensing performance under\nvarious bending conditions and could be further fabricated into the\nfiber gas sensor device via wet stretching, retaining response at\nthe ppb level (with a response of 18.6% to 100 ppb H<sub>2</sub>S).\nThis research on a flexible gas sensor device based on the CNT film/fiber\nopened up new possibilities for wearable portable electronic device\napplications.