Flexible Gas Sensors Based on Carbon Nanotube Hybrid Films: A Review

Abstract Flexible gas sensors, which can detect gas markers from the human body and hazardous gases from the environment, are attracting tremendous attention recently. Carbon nanotube (CNT) films are explored for flexible gas sensors due to its sensing ability at room temperature, strong adsorption for foreign molecules, mechanical robustness, and remarkable flexibility, and providing nanoscale surfaces with large surface area for various functional materials, etc. In this paper, recent advances in flexible gas sensors based on CNT films are reviewed. It discusses various strategies to design the structure of flexible CNT films and improve flexibility/stretchability performance. It generalizes different types of sensitive materials loaded for detected gases and analyzes the sensing mechanism of CNT films, with interface interactions and synergistic effects leading to an improvement in gas sensing. In addition, it discusses the preparation of CNT self‐standing films and the use of flexible substrates in transformation and assembly, in order to enable CNT films with improved flexible properties. CNT films show remarkable response and flexibility to hazard or greenhouse gases, such as ammonia, nitrogen dioxide, hydrogen, nitric oxide, carbon dioxide, and others. Summary and perspectives toward the future development of flexible gas sensors based on CNT films are proposed.