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All-aerosol-jet-printed highly sensitive and selective polyaniline-based ammonia sensors: a route toward low-cost, low-power gas detection

Publication Type
Journal Name
Journal of Materials Science
Publication Date
Page Numbers
12596 to 12606

Advancement towards cost effective, compact, and reliable detection of low concentrations of ammonia (NH3) gas is im-perative for environmental monitoring, human safety, and medical diagnostics. Herein, we report the design and scalable fabrication of a low-cost and low-power polyaniline-based (PANI) NH3 gas sensor on flexible polyimide (PI) substrates using additive manufacturing techniques. The silver interdigitated electrode (IDE) arrays and conducting polymer films are printed onto PI using a direct-write technology of aerosol-jet printing. Morphological characteristics are examined by scanning electron microscopy and energy dispersive X-ray analysis which reveal homogeneously printed PANI film on the IDE platform. The gas sensing performance is evaluated in the analytical early-leak-detection range of 5-1000 ppm NH3 in air as a function of both thermal (23 °C, 50 °C, 80 °C) and relative humidity (RH=0%, 30%, 50%) exposures. The sensor exhibits sensitivity down to 5 ppm NH3 with a sub-ppm detection limit and good repeatability. We observe rapid NH3 detection at 0% RH with full response and recovery to baseline requiring several hours. However, at both 30% and 50% RH, the room temperature response and recovery times are reduced to only about 1 min and 5 min, respectively. Experiments also reveal good sensitivity towards the analyte even at higher operating temperatures. Present results merit the practical application of flexible, aerosol-jet printed, low-power sensors for industrial applications where low-level hazardous gas detection is essential.