A review on chemiresistive gas sensors based on carbon nanotubes: Device and technology transformation

With the development of technology, process control has become central to the working of modern industries as well as devices. Sensors are at the heart of these advances: where, the need for high sensitivity, quick response as well as recovery, and low power consumption is imperative at economic prices. The use of nanomaterials has shown to greatly enhance the sensing performance of a device owing to the large surface area of such materials. The large surface-to-volume and pitted structure, along with extraordinary electrical and thermal conductivities, make it most favorable material for gas sensing applications. Major advancements in the CNTs based gas sensors involve the enhancing the sensitivity and selectivity of the nanotubes. This can be achieved by specific functionalization of CNTs with a variety of materials such as noble metals, metal oxides, polymers, etc. It has been found that, for sensor applications, modifications of CNTs with certain materials can enhance the selectivity and sensitivity of CNTs and make it sensitive towards several harmful gases. In this article, we present a comprehensive analysis of the past as well as present day CNTs gas sensors technology. The study presented in this paper are helpful to develop advanced devices with the application of highly efficient sensors. (C) 2018 Elsevier B.V. All rights reserved.