Prakash Jyoti, Rao Pandugula Thirmaleshwar, Rohilla Rohan, Nechiyil Divya, Kaur Manmeet, Ganapathi Kailasa S, Debnath Anil Krishna, Kaushal Amit, Bahadur Jitendra, Dasgupta Kinshuk
Materials Group, Bhabha Atomic Research Centre, Mumbai 400085, India.
Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400094, India.
ACS Omega. 2023 Feb 9;8(7):6708-6719. doi: 10.1021/acsomega.2c07314. eCollection 2023 Feb 21.
Lightweight and flexible gas sensors are essentially required for the fast detection of toxic gases to pass on the early warning to deter accident situations caused by gas leakage. In view of this, we have fabricated a thin paper-like free-standing, flexible, and sensitive carbon nanotube (CNT) aerogel gas sensor. The CNT aerogel film synthesized by the floating catalyst chemical vapor deposition method consists of a tiny network of long CNTs and ∼20% amorphous carbon. The pores and defect density of the CNT aerogel film were tuned by heating at 700 °C to obtain a sensor film, which showed excellent sensitivity for toxic NO and methanol gas in the concentration range of 1-100 ppm with a remarkable limit of detection ∼90 ppb. This sensor has consistently responded to toxic gas even after bending and crumpling the film. Moreover, the film heat-treated at 900 °C showed a lower response with opposite sensing characteristics due to switching of the semiconductor nature of the CNT aerogel film to n-type from p-type. The annealing temperature-based adsorption switching can be related to a type of carbon defect in the CNT aerogel film. Therefore, the developed free-standing, highly sensitive, and flexible CNT aerogel sensor paves the way for a reliable, robust, and switchable toxic gas sensor.
对于快速检测有毒气体以传递早期预警以防止因气体泄漏导致的事故情况而言，轻质且灵活的气体传感器是必不可少的。有鉴于此，我们制备了一种薄纸状的独立、灵活且灵敏的碳纳米管（CNT）气凝胶气体传感器。通过浮动催化剂化学气相沉积法合成的CNT气凝胶薄膜由长CNT的微小网络和约20%的无定形碳组成。通过在700℃下加热来调节CNT气凝胶薄膜的孔隙率和缺陷密度，从而获得一种传感器薄膜，该薄膜对浓度范围为1 - 100 ppm的有毒NO和甲醇气体表现出优异的灵敏度，检测限低至约90 ppb。即使在对薄膜进行弯曲和揉搓之后，该传感器对有毒气体仍能持续做出响应。此外，在900℃下进行热处理的薄膜由于CNT气凝胶薄膜的半导体性质从p型转变为n型而表现出较低的响应以及相反的传感特性。基于退火温度的吸附切换可能与CNT气凝胶薄膜中的一种碳缺陷类型有关。因此，所开发的独立、高灵敏且灵活的CNT气凝胶传感器为可靠、坚固且可切换的有毒气体传感器铺平了道路。
