Investigation of a flexible, room-temperature fiber-shaped NH3 sensor based on PANI-Au-SnO2.

Abstract

A sensitive compound was successfully obtained by coating polyaniline (PANI) on the surface of composite nanoparticles consisting of Au-loaded tin dioxide, named as PANI-Au-SnO2, using an in situ polymerization method. NH3 sensors in thin-film and fiber-shaped forms were prepared by inkjet printing and impregnation methods, respectively, based on PANI-Au-SnO2. The response characteristics of these NH3 sensors developed from composite sensitive materials were investigated in detail. Results indicate an effective response of the sensors to NH3 at room temperature. The thin-film sensor demonstrated a good linear relationship between the resistance change and NH3 concentration within the range of 5-40 ppm, indicating its excellent repeatability and long-term stability. In comparison to the thin film sensor, the fiber-shaped sensor showed a consistently stable response to NH3 even after 1000 cycles of repeated bending deformation. To demonstrate the practical application of the flexible fiber-shaped NH3 sensor, a cap designed for NH3 detection was fabricated by integrating the as-prepared sensor with a circuit board and an LED digital display. This assembly was incorporated into a commercially available ducktail cap, resulting in a wearable device capable of dynamically monitoring environmental NH3 levels and displaying real-time values. This innovative application underscores the potential of these sensors in real-world scenarios, particularly in occupational safety, where workers might be exposed to harmful levels of NH3. The cap could serve as a personal safety device, alerting the wearer to hazardous concentrations of NH3, which is particularly relevant in industrial or agricultural settings.