All laser printed resistive chemical sensor: Fabrication and evaluation

Abstract

Flexible electronics are an evolving field that has spurred the interest of many researchers during the last decade, due to the wide range of potential emerging applications including displays, sensors, radio-frequency identification tags, etc. In this work, we present our latest results on the fabrication of a flexible (polyimide), all laser printed chemical sensor device for the detection of humidity vapors. Firstly, a surface treatment process was used to improve the wettability of the substrate towards the printed features. The sensor device current architecture is able to host 7 pairs of electrodes, which have been formed by the pulsed laser printing of a viscous ink consisting of silver nanoparticles, while silver paste was also used so as to provide the electrical wiring interconnection of the device with the outside world. Regarding the sensing element of the sensor, an aqueous graphene oxide solution was laser printed on top of the pre-deposited electrodes. A subsequent thermal reduction step was employed to reduce the graphene oxide and obtain conductive patterns. Sensor performance evaluation was conducted upon flow of different concentrations of humidity vapors to the sensor, and good response with reproducible operation was observed.