A Flexible NO2 Gas Sensor Based on Single-Wall Carbon Nanotube Films Doped with a High Level of Nitrogen

• Published in: Molecules (Basel, Switzerland) Vol. 27; no. 19; p. 6523
• Main Authors: Tian, Xiao-Han, Zhou, Tian-Ya, Meng, Yu, Zhao, Yi-Ming, Shi, Chao, Hou, Peng-Xiang, Zhang, Li-Li, Liu, Chang, Cheng, Hui-Ming
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 02.10.2022; MDPI
• Subjects: Carbon; Electrodes; flexible sensor; Gases; Internet of Things; Nitrogen; nitrogen doping; Sensors; single-wall carbon nanotube; Spectrum analysis
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules27196523

Carbon nanotubes (CNTs) are considered a promising candidate for the detection of toxic gases because of their high specific surface area and excellent electrical and mechanical properties. However, the detecting performance of CNT-based detectors needs to be improved because covalently bonded CNTs are usually chemically inert. We prepared a nitrogen-doped single-wall CNT (SWCNT) film by means of gas-phase fluorination followed by thermal annealing in NH3. The doped nitrogen content could be changed in the range of 2.9–9.9 at%. The N-doped SWCNT films were directly used to construct flexible and transparent gas sensors, which can work at a low voltage of 0.01 V. It was found that their NO2 detection performance was closely related to their nitrogen content. With an optimum nitrogen content of 9.8 at%, a flexible sensor had a detection limit of 500 ppb at room temperature with good cycling ability and stability during bending.