A novel paper-based flexible ammonia gas sensor via silver and SWNT-PABS inkjet printing

The manuscript reports a novel and simple fabrication of paper-based flexible ammonia gas (NH3) sensor with silver and poly(m-aminobenzene sulfonic acid) functionalized single-walled carbon nanotubes (SWNT-PABS) via inkjet printing. Silver dispersion was first inkjet printed onto the photo-paper to prepare the electrodes with different configurations. SWNT-PABS dispersion was then printed onto pre-printed silver electrodes to fabricate the ammonia gas sensor. The rheological behaviors of SWNT-PABS dispersion and surface structures of fabricated sensors were characterized. The effects of electrode configuration and the number of SWNT-PABS printed layers on the electric resistance of sensors were studied. The paper-based sensor showed excellent sensor response, short response and recovery time to different concentrations of NH3 at ppm level, and could be stable for several months. This fabrication method assembling electrodes and testing parts onto the flexible photo-paper is simpler, more efficient, and cost effective.