Tunable Electrical-Sensing Performance of Random-Alternating Layered Graphene/Polyaniline Nanoarchitectures

Nanostructured materials feature a high surface-to-volume ratio and small dimensions, which are highly beneficial for sensor applications. In this work, graphite was physically exfoliated by a conducting polymer polyaniline (PANI), which resulted in the formation of random-alternating layered graphene/PANI (G-PANI) nanoarchitectures. Resistometric sensors were assembled using a G-PANI nanoarchitecture film as the transducer electrode to examine the characteristics of the G-PANI nanoarchitectures in sensor applications. The sensing performance of the electrode depended on the type of dopant employed, and more importantly, the unique geometrical composition of the nanoarchitecture gave rise to anisotropic electrical properties. A series or parallel connection-like configuration of intercalated PANI nanolayers was formed when a voltage was applied perpendicular or parallel to the stacked graphene plane. Compared with the parallel connection-like configuration, the series connection-like configuration yielded a far better sensing performance, particularly in terms of sensitivity. For the series connection-like configuration, electrochemical impedance spectroscopy analysis confirmed that the nanoarchitecture film was comprised of numerous resistance circuit elements arranged in a chain.