A flexible and room-temperature operatable gas sensor for robotic olfaction: selective detection of formic acid via UV excitation

Robotic olfaction requires gas sensors that are intrinsically safe, mechanically compliant, and capable of selective operation at room temperature. Here, we present a flexible and room-temperature operable gas sensor for formic acid (FA) detection based on a UV-assisted PAM/CA organohydrogel sensing layer. The sensing response is associated with FA adsorption, diffusion, dissociation in the local hydrogel environment, and interfacial electrochemical processes. Photocurrent and UPS measurements indicate that the UV effect should not be interpreted as semiconductor-like photogenerated carrier generation, but rather as UV-assisted physicochemical modulation of the hydrogel interface. The organohydrogel provides good conformability, environmental tolerance, and stable operation under bending deformation. By combining static UV excitation with dynamic UV-intensity modulation, the sensor achieves ppm-level FA detection and improved discrimination among homologous organic acids. Building on this platform, we develop a conformable electronic nose for robotic integration and demonstrate proof-of-concept FA leak inspection in a simulated factory scenario. This work provides a feasible system-level strategy for flexible, room-temperature gas sensing and robotic olfaction integration.