D. Meka, V. Onbattuvelli, S. Atre, S. Prasad
palladium, SO2 sensor, polymer, nanocomposites, carbon nanoparticles
Here we present a highly sensitive nanocomposite based Chemiresistive SO2 sensor. The main objective of this research is focused on developing a cost effective, integrable and disposable gas sensor which detects SO2 gas molecules in the ambient air with high sensitivity and selectivity. Sulfur Dioxide (SO2) is one of the six common air pollutants that are released into the atmosphere which causes a wide variety of health and environmental impacts like respiratory effects, visibility impairments, acid rains, etc., because of the way it reacts with other substances in the air. So, it is necessary to control the emission of this gas into the atmosphere by various sources. In order to control the emission of this harmful gas it should be first detected. The technique used in the detection of the SO2 gas molecules is Chemiresitive technique, in which there will be a change in electrical resistance associated with the adsorption of SO2 molecules by the nanocomposite. Since, Palladium has a very high affinity towards adsorbing sulfur compounds; Pd is a promising element for the selective detection of SO2 gas in the ambient air. There will be a change in electrical properties of the Pd/Polymer nanocomposite due to the adsorption of the SO2 molecules by the Pd nanoparticles. Thus, Pd/Polymer nanocomposite acts as a transducer which translates the change in SO2 gas concentration in air to a detectable electrical signal. Incorporation of carbon nanoparticles into the nanocomposite improves the change in electrical signal resulted due to the adsorption of SO2 gas molecules in the air. Presently, we are able to detect the SO2 in parts per million (1 ppm) ranges in ambient conditions. Another advantage of this detection technique is it requires only a simple photolithography based fabrication scheme that can be executed on a non specialized wet bench making the sensor less expensive and robust. The main draw back with this detection technique is lack of selectivity. But, by employing the Pd nanoparticles in sensing the SO2 gas molecules overcomes this particular drawback to certain extent. Future work of this research is mainly focus on proper tailoring of the Pd/Polymer nanocomposite in order to improve the selectivity of the nanocomposite towards SO2 gas, and secondly on improving design of the electrode pattern in order to improve the sensitivity of the sensor from ppm range to ppb range.