Fabrication of high-performance NH₃ flexible sensor based on PANI/SnO₂ hollow nanosphere composite

The development of NH₃ sensors with efficient room temperature detection is crucial for Internet of Things-driven smart agriculture. Herein, PANI/SnO₂ hollow nanospheres composites were in situ synthesized on flexible interdigital electrodes (PET-IDE). Within the PANI/SnO₂ composites microstructure, the SnO₂ 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 SnO₂ hollow spheres and the PANI film promotes the creation of p-n heterojunction, thereby significantly improving the NH₃ gas-sensing performance. The 4PS-based sensor (the PANI/SnO₂ composite obtained at 0.04 mol·L^-1 APS/HCl solutions) exhibited a high response (9.63) toward 100 ppm NH₃, along with excellent selectivity and stability. Correlations between microstructure and NH₃ gas-sensing behavior were systematically investigated, offering theoretical insights for sensor optimization.