Exploring the structure and electronic properties of individual hybrid GO/rGO flakes

Despite its great potential, the use of graphene oxide (GO) in sensors, photocatalysis, or biomedicine applications is limited by its low conductivity. This drawback is typically overcome by using its reduced form (rGO) albeit sacrificing some of its extensive chemical properties. In this study, we unveil a nonuniform reduction process that enables the fabrication of hybrid flakes consisting of both size tunable GO and rGO regions. The nanoscale resolution of Kelvin probe force microscopy together with co-localized Raman spectroscopy allow us to correlate the local reduction degree with the nanoscale electronic properties, chemical composition, and structural defects. Additionally, we introduce a reliable metric for quantifying the extent of reduction. This research opens up possibilities for the development of new 2D nanohybrid materials that combine the high reactivity of GO and the enhanced conductivity of rGO, enabling applications in selective functionalization.