Ultrasensitive Flexible NO₂ Gas Sensors via Micromesh-Structured Rubbery Semiconductor Films

With the rapid development of smart devices, gas sensors have attracted widespread attention as basic components for detecting, monitoring, and warning of hazardous gases in the human environment. However, most semiconductors are inherently inelastic, which can cause mechanical damage and allergic inflammation to human tissues, and the fabrication of flexible gas sensors with both good sensing performance and mechanical flexibility remains a challenge. In this study, we present a scalable and simple preparation method to construct a transistor-based gas sensor with significantly enhanced gas sensing capability and stretchability. The formed rubbery structure provides an effective noxious gas diffusion channel, abundant active sites for gas molecule adsorption, and robustness. The results show that the films prepared by this method have a high sensitivity (≈103.2% ppm−1), an ultralow limit of detection (LOD) (∼0.2 ppm), a fast response time (3 s), and good gas selectivity. In addition, the apparatus demonstrated operational efficiency at a 50% tensile strain. The excellent performance of the flexible gas sensor demonstrates its potential for future wearable devices with real-time gas monitoring functions.