Highly Sensitive Chemo-Resistive Ammonia Sensor Based on Dodecyl Benzene Sulfonic Acid Doped Polyaniline Thin Film

Dodecyl benzene sulfonic acid (DBSA) doped polyaniline (PANI) has been synthesized by ex-situ doping in emeraldine base (EB). The optical and functional properties of as synthesized DBSA doped PANI (PANI-DBSA) have been studied by UV-Visible and FTIR spectroscopy, respectively. A chemo-resistive gas sensor was prepared using spin coated PANI-DBSA thin film for quantitative detection of ammonia (NH3) under ambient conditions (27 degrees C, 50% RH). The sensing characteristics of fabricated sensor were recorded using the dynamic resistance measurement, that revealed high sensitivity in relative response (similar to 4.5), response time (similar to 55 sec) and rapid recovery (similar to 100 sec). The PANI-DBSA thin film sensor shows good linearity (R = 0.996) and repeatability over a wide concentration range of NH3 from 5 to 250 ppm.