EFFECT OF ELECTRODE MATERIAL ON SENSOR RESPONSE

The present study describes the effect of electrode material on the pe rformance of a screen-printed thick-film SnO2 gas sensor. The response of the sensor, i.e., the percentage change in the sensor resistance u pon exposure to H-2, CO and CH4, has been studied for two different el ectrodes of silver and gold. It has been observed that the sensitivity of the thick-film SnO2 sensor for H-2 and CO with silver (Ag) is much higher (about 65.5% and 42.6%, respectively) as compared to the Au-el ectrode sensor. A possible mechanism for the higher sensitivity of the Ag-based SnO2 sensor has been suggested in terms of autodoping at the time of firing of the SnO2 layer. The idea of autodoping has been con firmed by performing Ag doping of SnO2 (with a Au electrode) and study ing its performance.