Miniaturized Gas Sensor Platform for Selective Vapors Detection at Room Temperature

Abstract

Gas sensors are usually made of metallic oxides and need to operate at relatively high temperatures (about hundreds of Celsius degrees). Besides, they generally present drawbacks: low selectivity, elevated response time, and degradation. Novel nanostructured materials such as carbon nanotubes and graphene, among others, have been proposed to overcome these problems due to their unique electronic properties. However, these materials also present low selectivity for many gas species. In order to take advantage of the benefits of using carbon materials for gas sensing at room temperature, this work presents a proposal of humidity and volatile organic compounds (VOCs) sensing based on a miniaturized platform composed of four sensors. The lack of selectivity of individual materials is compensated by crossing the responses of each sensor. Results showed very fast response and recovery times (just few seconds), as well as good sensitivity (response variation up to four orders of magnitude). With this approach, the selectivity to discriminate the vapors can be improved, since each substance has an individual response pattern in the gas sensor array.