Present paper reports the synthesis of SnO2, its characterization and performance as Liquefied Petroleum Gas (LPG) Sensor. XRD pattern revealed the tetragonal crystalline nature of the material. Crystallites sizes wer...Present paper reports the synthesis of SnO2, its characterization and performance as Liquefied Petroleum Gas (LPG) Sensor. XRD pattern revealed the tetragonal crystalline nature of the material. Crystallites sizes were in the range 14 - 30 nm. Tin oxide thick film was prepared by using screen printing technique. After that these were investigated through SEM. SEM image of thick-film surface was spherical in shape and porous. Further at room temperature, the film was exposed to LPG in a controlled gas chamber and variations in resistance with the concentrations of LPG were observed. The maximum value of average sensitivity of thick film was 37 MΩ/min for 5 vol. % of LPG. Sensor responses as a function of exposure and response times were also estimated and maximum sensor response were found 273 and 312 for 4 and 5 vol. % of LPG respectively.展开更多
Pure ZnO thick film, prepared by screen-printing technique, was almost insensitive to NH3. Pure ZnO thick films were surface modified with MnO2 by dipping them into 0.01 M aqueous solution of manganese chloride (MnCl2...Pure ZnO thick film, prepared by screen-printing technique, was almost insensitive to NH3. Pure ZnO thick films were surface modified with MnO2 by dipping them into 0.01 M aqueous solution of manganese chloride (MnCl2) for different intervals of time and fired at 500℃ for 12 h. The grains of MnO2 would disperse around the grains of ZnO base material. The MnO2 modified ZnO films dipped for 30 min were observed to be sensitive and highly selective to NH3 gas at room temperature. An exceptional sensitivity was found to low concentration (50 ppm) of NH3 gas at room temperature and no cross sensitivity was observed even to high concentrations of other hazardous and polluting gases. The effects of surface microstructure and MnO2 concentrations on the sensitivity, selectivity, response and recovery of the sensor in the presence of NH3and other gases were studied and discussed. The better performance could be attributed to an optimum number of surface misfits in terms of MnO2 on the ZnO films.展开更多
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 u...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 ？C？350 ？C） upon exposure to methanol, propanol and acetone, yielding a maximum at 250 ？C for acetone with 1 wt% PbO-doping while at 350 ？C 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.展开更多
文摘Present paper reports the synthesis of SnO2, its characterization and performance as Liquefied Petroleum Gas (LPG) Sensor. XRD pattern revealed the tetragonal crystalline nature of the material. Crystallites sizes were in the range 14 - 30 nm. Tin oxide thick film was prepared by using screen printing technique. After that these were investigated through SEM. SEM image of thick-film surface was spherical in shape and porous. Further at room temperature, the film was exposed to LPG in a controlled gas chamber and variations in resistance with the concentrations of LPG were observed. The maximum value of average sensitivity of thick film was 37 MΩ/min for 5 vol. % of LPG. Sensor responses as a function of exposure and response times were also estimated and maximum sensor response were found 273 and 312 for 4 and 5 vol. % of LPG respectively.
文摘Pure ZnO thick film, prepared by screen-printing technique, was almost insensitive to NH3. Pure ZnO thick films were surface modified with MnO2 by dipping them into 0.01 M aqueous solution of manganese chloride (MnCl2) for different intervals of time and fired at 500℃ for 12 h. The grains of MnO2 would disperse around the grains of ZnO base material. The MnO2 modified ZnO films dipped for 30 min were observed to be sensitive and highly selective to NH3 gas at room temperature. An exceptional sensitivity was found to low concentration (50 ppm) of NH3 gas at room temperature and no cross sensitivity was observed even to high concentrations of other hazardous and polluting gases. The effects of surface microstructure and MnO2 concentrations on the sensitivity, selectivity, response and recovery of the sensor in the presence of NH3and other gases were studied and discussed. The better performance could be attributed to an optimum number of surface misfits in terms of MnO2 on the ZnO films.
文摘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 ？C？350 ？C） upon exposure to methanol, propanol and acetone, yielding a maximum at 250 ？C for acetone with 1 wt% PbO-doping while at 350 ？C 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.
