Fabrication of high-performance NH flexible sensor based on PANI/SnO hollow nanosphere composite.

The development of NH sensors with efficient room temperature detection is crucial for Internet of Things-driven smart agriculture. Herein, PANI/SnO hollow nanospheres composites were in situ synthesized on flexible interdigital electrodes (PET-IDE). Within the PANI/SnO composites microstructure, the SnO hollow spheres can provide effective support to the PANI film, minimize agglomeration, and enhance the functional performance of PANI. Furthermore, the extensive interface between the SnO hollow spheres and the PANI film promotes the creation of p-n heterojunction, thereby significantly improving the NH gas-sensing performance. The 4PS-based sensor (the PANI/SnO composite obtained at 0.04 mol·L APS/HCl solutions) exhibited a high response (9.63) toward 100 ppm NH, along with excellent selectivity and stability. Correlations between microstructure and NH gas-sensing behavior were systematically investigated, offering theoretical insights for sensor optimization.