Flexible NH3 sensor based on spray deposition and inkjet printing

This paper presents a fully printed gas sensor on a flexible substrate. The sensitive film is based on carbon nanotubes (CNT) deposited by spray by an air atomizing nozzle, whereas the electrodes were defined by inkjet printing of silver nanoparticles. The results obtained for NH₃ sensing using CNT films deposited on polyimide show good performance in terms of sensitivity and time response to the test gas, with performance comparable with that obtained with evaporated metal electrodes. In addition, we demonstrate the feasibility of inkjet printing the electrodes on top of sprayed CNT layers. This work represents an important step toward large-scale and low-cost fabrication of such a class of devices.