Poly(m-aminobenzene sulfonic acid) functionalized single-walled carbon nanotubes based gas sensor

We have demonstrated a NH 3 , NO 2 and water vapour sensor based on poly(m-aminobenzene sulfonic acid) functionalized single-walled carbon nanotube (SWNT–PABS) networks. The SWNT–PABS based sensors were fabricated by simple dispersion of SWNT–PABS on top of pre-fabricated gold electrodes. SWNT–PABS sensors showed excellent sensitivity with ppb v level detection limits (i.e., 100 ppb v for NH 3 and 20 ppb v for NO 2 ) at room temperature. The response time was short and the response was totally reversible. The sensitivity could be tuned by adjusting the sensor initial resistance. The sensors were also suitable for monitoring relative humidity in air.