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Phenyl Functionalization of Atomically Precise Graphene Nanoribbons for Engineering Inter-ribbon Interactions and Graphene Nanopores
journal contribution
posted on 2018-08-07, 00:00 authored by Mikhail Shekhirev, Percy Zahl, Alexander SinitskiiGraphene
nanoribbons (GNRs) attract much attention from researchers
due to their tunable physical properties and potential for becoming
nanoscale building blocks of electronic devices. GNRs can be synthesized
with atomic precision by on-surface approaches from specially designed
molecular precursors. While a considerable number of ribbons with
very diverse structures and properties have been demonstrated in recent
years, there have been only limited examples of on-surface synthesized
GNRs modified with functional groups. In this study, we designed a
nanoribbon, in which the chevron GNR backbone is decorated with phenyl
functionalities, and demonstrate the on-surface synthesis of these
GNRs on Au(111). We show that the phenyl modification affects the
assembly of the GNR polymer precursors through π–π
interactions. Scanning tunneling spectroscopy of the modified GNRs
on Au(111) revealed that they have a band gap of 2.50 ± 0.02
eV, which is comparable to that of the parent chevron GNR. The phenyl
functionalization leads to a shift of the band edges to lower energies,
suggesting that it could be a useful tool for the GNR band structure
engineering. We also investigated lateral fusion of the phenyl-modified
GNRs and demonstrate that it could be used to engineer different kinds
of atomically precise graphene nanopores. A similar functionalization
approach could be potentially applied to other GNRs to affect their
on-surface assembly, modify their electronic properties, and realize
graphene nanopores with a variety of structures.