掺杂Au改善SnO2甲苯气敏元件性能的研究

SnO2掺杂Au，WO3，La制备了纳米材料，采用丝网印刷方法获得平面厚膜型甲苯气敏元件，通过测量材料的气敏特性和复阻抗谱，探讨了掺杂对元件的灵敏度、选择性和响应速度的影响。结果表明：Au掺杂能极大地提高元件对甲苯的灵敏度，在体积分数为100×10^-6甲苯气氛中灵敏度达35，元件的响应时间约为20s，恢复时间约为10s，对乙醇、甲醛、丙酮和苯气氛有良好的选择性。复阻抗分析说明对甲苯气氛的灵敏度来源于晶界电阻和晶界电容的变化。灵敏度提高与掺Au有效地改善了界面的氧吸附效应有关。

Study on gas-sensing property of Au-doped SnO_2 toluene sensor

SnO2 nano-powders mixed with Au,WO3 and La are prepared.Thick films to1uene sensors are fabricated in a planar structure by silk-screen printing.The effects of additives on the properties of SnO2 gas-sensors such as sensitivity,selectivity and response properties are researched according to electronic measuring and complex-impedance spectra.The results show that doping of Au can obviously improve the sensitivity of the sensor to toluene,when volume fraction of toluene is 100×10-6,the sensitivity is 35.The response time and the recover time of sensor is 20 s and 10 s respectively,the selectivity to alcohol,formaldehyde,acetone and benzene gases is good.The complex impedance analysis means that the sensitivity to toluene comes from the change of SnO2 grain-boundary resistance and grain-boundary capacitance.That is relational to the adsorption and desorption of surface oxygen-ion improved by the doping of Au.