Tailoring electronic states of nanographenes through heteroatom substitution and substrate interactions

Technology advances demand new materials for faster and more efficient electronics. Carbon-based nanostructures, particularly planar nanographenes, offer tunable electronic properties through atomic-scale design. This thesis explores different strategies to control these properties in nanographenes synthesized via on-surface synthesis (a bottom-up arrpoach in UHV) and characterized by scanning probe techniques. Three approaches are investigated: geometry and edge structure, heteroatom substitution, and substrate choice. Seventeen-atom-wide graphene nanoribbons are grown and integrated into devices, demonstrating favorable transport behavior. Nitrogen substitution, shown to be compatible with on-surface synthesis, enables doping of the nanographenes but leads to charge transfer to Au(111). To mitigate this effect, TbAu₂ is introduced as a substrate, enabling reduced charging and magnetic coupling. These findings highlight pathways to engineer nanographene electronic properties.