Sustainable, Flexible, and Ambient Temperature Operated Polyaniline-Based Chemiresistive Ammonia Sensor With Eco-Friendly Design

Abstract

In this work, an eco-friendly, flexible, and ambient temperature (∼27 °C ± 2 °C) operated ammonia (NH3) sensor has been developed using electrospun polyaniline (PANI) fibers deposited on an eco-friendly paper substrate having printed graphene–carbon (G-C) interdigitated electrodes (IDEs). The sensor was designed to detect NH3 over a broad concentration range of 0.5–500 parts per million (ppm), targeting applications in environmental and healthcare monitoring. Structural, elemental, and morphological properties of the sensing layer were characterized using X-ray diffraction, energy-dispersive X-ray spectroscopy, and scanning electron microscopy, confirming the formation of well-aligned PANI fibers with entangled networks and rougher surface. The sensor exhibited excellent % response (1261% at 500 ppm), reproducibility, and good repeatability over multiple cycles. Selectivity studies showed a multifold % response toward NH3 gas as compared to interfering gases, such as CO2, CO, SO2, and NO2. The use of paper as a low-cost, eco-friendly substrate, combined with the scalable fabrication route, highlights the potential of this work for sustainable and disposable NH3 sensing platforms and environmentally-friendly sensing solutions.