Fabrication of a novel 2D-graphene/2D-NiO nanosheet-based hybrid nanostructure and its use in highly sensitive NO_2 sensors

摘要

A highly sensitive gas sensor based on novel hybrid structures composed of 2D graphene and 2D NiO nanosheets (NSs) is fabricated using a low-cost, low temperature and large area scalable solution-based process. The highly developed hierarchically porous structures of 2D NiO sheets are grown on reduced graphene oxide (RGO) surfaces. Sensors fabricated with hybrid structures showed a responsivity and sensitivity two orders higher than that of a NiO NS alone toward NO_2 even at 1 ppm level. This is attributed to the effective carrier transfer from NiO NS to graphene and to the well-developed 2D NiO structure. The sensing results are similar when reducing gases such as H_2, NH_3 and H_2S are tested, but the responsivity toward NO_2 was highest among all the gases tested.