High-Performance Gas Sensor of Polyaniline/Carbon Nanotube Composites Promoted by Interface Engineering

• Published in: Sensors (Basel, Switzerland) Vol. 20; no. 1; p. 149
• Main Authors: Zhang, Weiyu, Cao, Shuai, Wu, Zhaofeng, Zhang, Min, Cao, Yali, Guo, Jixi, Zhong, Furu, Duan, Haiming, Jia, Dianzeng
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 25.12.2019; MDPI
• Subjects: Ammonia; Carbon fibers; carbon nanotubes; Composite materials; Depletion; gas sensor; Gas sensors; Gases; hierarchical structure; interface engineering; Internet of Things; Nitrogen dioxide; polyaniline; Polyanilines; Quantum dots; Response time; Sensors; Structural hierarchy; Time response; Beijing China; China; gas sensor; polyaniline; carbon nanotubes; hierarchical structure; interface engineering
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s20010149

Inspired by the enhanced gas-sensing performance by the one-dimensional hierarchical structure, one-dimensional hierarchical polyaniline/multi-walled carbon nanotubes (PANI/CNT) fibers were prepared. Interestingly, the simple heating changed the sensing characteristics of PANI from p-type to n-type and n-type PANI and p-type CNTs form p-n hetero junctions at the core-shell interface of hierarchical PANI/CNT composites. The p-type PANI/CNT (p-PANI/CNT) and n-type PANI/CNT (n-PANI/CNT) performed the higher sensitivity to NO and NH , respectively. The response times of p-PANI/CNT and n-PANI/CNT to 50 ppm of NO and NH are only 5.2 and 1.8 s, respectively, showing the real-time response. The estimated limit of detection for NO and NH is as low as to 16.7 and 6.4 ppb, respectively. After three months, the responses of p-PANI/CNT and n-PANI/CNT decreased by 19.1% and 11.3%, respectively. It was found that one-dimensional hierarchical structures and the deeper charge depletion layer enhanced by structural changes of PANI contributed to the sensitive and fast responses to NH and NO . The formation process of the hierarchical PANI/CNT fibers, p-n transition, and the enhanced gas-sensing performance were systematically analyzed. This work also predicts the development prospects of cost-effective, high-performance PANI/CNT-based sensors.