用电抗标定方法改善SnO2气敏元件的选择性

摘要

A method called reactance measurement way in this paper is used to measure the sensitivity and selectivity of SnO2 gas sensors. This method uses the characteristic of reactance peak in the dependence of reactance on frequency, it is that the high of reactance peak decreases and peak frequency shifts to higher frequency region with the increment of concentration of combustible gases. Using the ratio of reactance values in each testing gas(alcohol and LPG) at peak frequency in air, sensitivity and selectivity of gas sensors are greatly improved as compared with the traditional dc method using the ratio of resistance values. Reactance measurement way is a good means to improve the selectivity of SnO2 gas sensors.%本文采用复阻抗谱方法测试SnO2气敏元件，用元件在接触可燃性气体前后电抗值的变化，即电抗-频率关系曲线中电抗峰随可燃性气体浓度增加，峰高降低以及峰频位置向高频移动的特性，来标定元件的气体灵敏度和选择性，简称电抗标定。结果表明，与传统的直流电阻标定方法相比较，元件的灵敏度显著提高，更有意义的是元件的选择性得到很大改善。因此，电抗标定方法是一种显著改善SnO2气敏元件灵敏度和选择性的新方法。