On-surface Synthesis and Characterization of Triply-fused Porphyrin-Graphene Nanoribbon Hybrids

Abstract

On‐surface synthesis offers a versatile approach to fabricate novel carbon‐based nanostructures that cannot be obtained via conventional solution chemistry. Within the family of such nanomaterials, graphene nanoribbons (GNRs) hold a privileged position due to their high potential for a variety of applications. One of the key issues for their application in molecular electronics lies in the fine‐tuning of their electronic properties through structural modifications, such as heteroatom doping or the incorporation of non‐benzenoid rings. In this context, the covalent fusion of GNRs and porphyrins (Pors) represents a highly appealing strategy. In this work, we present the selective on‐surface synthesis of a Por‐GNR hybrid, which consists of two Pors connected by a short GNR segment. The atomically precise structure of the obtained dimer has been unambiguously characterized by bond‐resolved scanning tunneling microscopy (STM) and noncontact atomic force microscopy (nc‐AFM). The electronic properties of the dimer have been investigated by STS in combination with DFT calculations, which reveals a low electronic gap of 0.4 eV.