In Situ-Polymerized PANI/WS2 Nanocomposites for Highly Sensitive Flexible Ammonia Gas Sensors and Respiration Monitoring Devices

This study reports PANI/WS2 gas-sensitive sensing materials synthesized with in situ polymerization for high-performance, wearable, flexible gas sensors. The gas sensors were constructed on flexible interdigital electrodes (IDEs) using a drop-coating self-assembly method. Due to the p–n junction structure formed by polyaniline (PANI) and tungsten disulfide (WS2), PANI doped with 2 wt % WS2 exhibits excellent properties for flexible sensors at room temperature, including high sensitivity, flexibility, and selectivity. The flexible sensor remains sensitive to NH3 at 100 ppb and maintains a good sensing performance under bending conditions. The mechanism of improved gas-sensitive performance due to p–n junctions has been investigated. In addition to gas sensing applications, a real-time human breath testing device was designed based on a PANI/WS2 composite membrane, demonstrating its potential application in health assessment.