Capacitive gas and vapor sensors using nanomaterials

An immense number of sensors has been reported in the literature employing various methods for the detection of different gases and vapors. This article summarizes those sensors whose sensing layer is made up of nanostructured materials and a change in capacitance value of device is the key parameter for detecting a gas or vapor. Now-a-days, capacitive sensors are emerging as they consume less power, operate well at room temperature and show decent response and recovery time. The sensing principles, configurations, mechanisms and performances of capacitive sensors based on different nanostructures are summarized and discussed in the current article. Emerging carbon based nanomaterials like carbon nanotube and graphene are also highlighted for capacitive mode detection of gases and vapors. Finally, an outlook of primary challenges in this field are identified and discussed at the end of the review.