Structural and micro structural studies of PbO-doped SnO2 sensor for detection of methanol,propanol

In the present work the structural information of PbO-doped SnO2 thick film sensor has been investigated with X-ray diffractometer(XRD)and scanning electron microscope(SEM).Initially,SnO2 powder was derived using sol-gel process and was subsequently doped with PbO and ground up to nanosized particles.A suitable gas sensor structure was fabricated on 1"× 1"alumina substrate using thick film technology.The necessary paste for screen printing was also developed.SEM results showed sol-gel derived powder gets more agglomerated in the thick film form.The sensitivity of the sensor has been investigated at different temperatures(150℃-350℃)upon exposure to methanol,propanol and acetone,yielding a maximum at 250℃ for acetone with 1 wt% PbO-doping while at 350℃ for propanol with 3 wt% PbO-doping of the sensor.The reduction of particle size to nanometers(validated through XRD)leads to a dramatic improvement in sensitivity of sensors for the chosen organic vapors.The results also correlate well with the microstructural properties of the material and the dopant.