Zigzag graphene nanoribbons with periodic porphyrin edge extensions.

Graphene nanoribbons (GNRs) with zigzag edges are promising materials for spintronic devices due to tunable bandgaps and spin-polarized edge states. Porphyrins offer complementary benefits such as desirable optoelectronic properties. Here we combine these features in a hybrid system by means of the on-surface synthesis of zigzag-edge GNRs embedded with porphyrins laterally fused along the ribbon backbone. Using scanning probe methods, we show that this design achieves strong electronic coupling between the porphyrin and the GNR. For transition metal porphyrins, pronounced exchange coupling between distant metal centres is mediated by the π-electron system. Such a hybrid d and π electron ribbon system introduces spin-orbit coupling and magnetic anisotropy to carbon nanomaterials, and holds great promise for coherent electrical control of electron spins.