摘要
Food spoilage in perishable, protein-rich products is a significant challenge for the food storage industry. This work introduces a UV-enhanced chemiresistive sensor, based on a polyaniline (PANI) nanocomposite functionalised with copper nitride‑silver (Cu 3 N-Ag) nanoparticles, for the rapid and selective detection of ammonia (NH 3 ). Under 365 nm UV illumination, the sensor exhibits a 4.7-fold sensitivity enhancement, achieving a linear response (R 2 = 0.99) from 5 to 200 ppm NH 3 with a detection limit of 1.03 ppm. A key finding is the intrinsically fast kinetics of the sensor, with a response time of approximately 30s and a recovery time of 50s. This suggests the enhancement mechanism is primarily a sensitivity amplification driven by electron-hole separation. The sensor demonstrated high selectivity against common interferents. Its operational principles, particularly the favourable electronic properties of the Ag-doped nanostructure, were further elucidated by density functional theory (DFT) calculations. Real-world validation successfully monitored NH 3 emissions from spoiling mutton and fish within 3–5 h. By providing a unique combination of rapid response and UV-tuneable sensitivity, supported by theoretical modelling, this technology holds significant potential for monitoring food wastage and for detecting NH 3 overexpression related to conditions like kidney or liver disease.