Flexible fabric gas sensors based on PANI/WO₃ p−n heterojunction for high performance NH₃ detection at room temperature

A PANI/WO₃@cotton thread-based flexible sensor that is capable of detecting NH₃ at room temperature is developed here. A layer of WO₃ with PANI nanoparticles can be deposited by in-situ polymerization. The morphology and structure of the specimens were investigated by utilizing TEM, SEM, XRD and FTIR. The sensing performance of the PANI/WO₃@cotton sensors with different WO₃ molar ratios to NH₃ at room temperature was examined. The results show that the optimal sensor (10 mol% WO₃) has a response of 6.0 to 100 ppm NH₃, which is significantly higher than that of the sensors based on pristine PANI and other composites. The PANI/WO₃@cotton sensor also displays excellent selectivity, gas response, and flexibility even at room temperature. The unique fiber structure, p-n heterojunction, and the increased protonation of PANI in the composites contribute to the enhanced sensing property.