Fabrication of flexible room-temperature NO2 sensors by direct laser writing of In2O3 and graphene oxide composites

In this work, we reported the fabrication of flexible NO2 sensors arrays operating at room temperature on a composite film of In2O3 and graphene oxide (GO) by direct laser writing (DLW) technology. The laser treatment not only induced the photoreduction of GO, leading to a highly porous structure due to the removal of oxygen groups, but also permitted mask-free patterning through a programmable manner, enabling flexible integration of sensor arrays on any substrates. We demonstrated the fabrication of a 2x4 NO2 sensors array on a flexible polyimide substrate within 10 min. Our NO2 sensors based on In2O3 and reduced GO (In2O3@RGO) show liner NO2 sensing properties at room temperature, good responsivity and recovery properties, as well as excellent selectivity towards NO2. We deem that the DLW fabrication of flexible NO2 sensorsarrays may contribute to the development of flexible electronics.