Visible-light-driven porphyrin/ZnO nanohybrids for ultrasensitive room-temperature triethylamine sensing

Real-time monitoring of toxic triethylamine (TEA) at room temperature remains a significant challenge for metal oxide chemiresistors due to their typically high-power consumption and thermal requirements. This work presents a highly responsive, visible-light-activated gas sensor based on ZnO nanoparticles (25.5 nm crystallites) functionalized with Cu-porphyrin (CuTPPCOOH). By leveraging the visible-light-harvesting properties of the porphyrin integrated into a nanoscale organic/inorganic heterojunction, the hybrid sensor operates efficiently at room temperature, completely eliminating the need for thermal heating. Owing to the nanoscale dimensions of the oxide domains, which maximize boundary depletion region modulation, the optimized device exhibits an ultralow theoretical limit of detection of 0.4 ppb and a superior response (162 toward 10 ppm TEA), significantly outperforming pristine ZnO nanostructures and current state-of-the-art sensors. The sensing enhancement is driven by a synergistic photoinduced charge transfer at the functionalized nanometer-scale interface, which maximizes sensing response under visible light illumination. With demonstrated high selectivity, excellent moisture stability, and rapid response dynamics, this nanoengineered hybrid architecture offers a robust, low-power solution for next-generation environmental safety networks and portable TEA monitors