Comprehensive assessment of polyaniline based sensors for ultra-low power gas detection in environmental and health monitoring: Next-generation NH3 sensing

The growth of gas sensors (GSs) that combine high sensitivity, selectivity, and ultra-low power consumption has increased due to the high need for continuous ecological and health monitoring. Because of its strong acid–base interaction with NH 3 molecules, room-temperature functioning, and customizable electrical characteristics, polyaniline (PANI) has become one of the most promising conducting polymers for ammonia (NH₃) detection. This work offers a complete review of polyaniline-based sensors for next-generation NH₃ sensing, with a special focus on ultra-low power operation suited for wearable, portable, and Internet-of-Things (IoT) applications. Important elements are thoroughly examined and critically contrasted, including synthesis pathways, nanostructuring techniques, composite creation, device topologies, and transduction processes. Environmental and health monitoring needs are taken into consideration while analyzing performance indicators such as sensitivity, limit of detection (LOD), response and recovery times, selectivity, stability, and power consumption. The issues of humidity interference, long-term stability, and large-scale integration are discussed, along with recent developments that allow sub-ppm to ppb-level NH₃ detection at room temperature (RT) with low energy consumption. Finally, future research approaches are explored to guide the construction of robust, energy-efficient PANI-based NH₃ sensors for next-generation sensing platforms. In this work, we introduce a new NH 3 sensor based on PANI that uses the least amount of power possible to detect NH 3 at concentrations ranging from a few parts per billion (ppb) to as high as the parts-per-million (ppm) range. The study spans the years 2021–2025 and has 163 references.