On‐Surface Synthesis of Atomically Precise Graphene Nanoribbons

Talirz, Leopold; Ruffieux, Pascal; Fasel, Román

doi:10.1002/adma.201505738

Cited by 441 publications

(494 citation statements)

References 85 publications

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“…These processes, which often rely on lithographic or oxidative routes, are not suitable to produce GNRs with small widths (< 10 nm) and lead to uncontrolled edge structures. In the perspective of reaching a fine control of the GNR geometry, the bottom-up chemical synthesis of long GNRs with defined structures represents a major breakthrough [12][13][14][15][16]. It opens the possibility to obtain a variety of desired structures by correctly designing specific precursors and the assembly route.…”

Section: Introductionmentioning

confidence: 99%

Fluorescence from graphene nanoribbons of well-defined structure

Zhao

Rondin

Delport

et al. 2017

Carbon

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Graphene nanoribbons synthesized by the bottom-up approach with optical energy gaps in the visible are investigated by means of optical spectroscopy. The optical absorption and fluorescence spectra of two graphene nanoribbons with different structures are reported as well as the life-time of the excited states. The possibility of the formation of excimer states in stacks of individual graphene nanoribbons is discussed in order to interpret the broad and highly Stokes-shifted luminescence lines observed on both structures. Finally, combined atomic force microscopy and confocal fluorescence measurements have been performed on small aggregates, showing the ability of graphene nanoribbons to emit light in the solid state. These observations open interesting perspectives for the use of graphene nanoribbons as near-infrared emitters.

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Section: Introductionmentioning

confidence: 99%

Fluorescence from graphene nanoribbons of well-defined structure

Zhao

Rondin

Delport

et al. 2017

Carbon

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“…The use of specifically designed organic precursors provides for on-surface synthesis of atomically precise graphene nanoribbons56 with tunable band gap through heteroatom-doping or by modifying their lateral size and edge termination78910111213. In contrast, the growth of long-range ordered two-dimensional (2D) porous graphene in ultra-high vacuum (UHV) is still a major challenge, despite the use of various design concepts and surface reactions1415161718.…”

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confidence: 99%

Hierarchical on-surface synthesis and electronic structure of carbonyl-functionalized one- and two-dimensional covalent nanoarchitectures

et al. 2017

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The fabrication of nanostructures in a bottom-up approach from specific molecular precursors offers the opportunity to create tailored materials for applications in nanoelectronics. However, the formation of defect-free two-dimensional (2D) covalent networks remains a challenge, which makes it difficult to unveil their electronic structure. Here we report on the hierarchical on-surface synthesis of nearly defect-free 2D covalent architectures with carbonyl-functionalized pores on Au(111), which is investigated by low-temperature scanning tunnelling microscopy in combination with density functional theory calculations. The carbonyl-bridged triphenylamine precursors form six-membered macrocycles and one-dimensional (1D) chains as intermediates in an Ullmann-type coupling reaction that are subsequently interlinked to 2D networks. The electronic band gap is narrowed when going from the monomer to 1D and 2D surface-confined π-conjugated organic polymers comprising the same building block. The significant drop of the electronic gap from the monomer to the polymer confirms an efficient conjugation along the triphenylamine units within the nanostructures.

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“…13) and Cu (refs 14, 15). Surface-assisted cyclodehydrogenations161718, a key step in GNR formation, appear to take place only on the catalytic metal substrates1920. Efforts of growing GNRs from molecular precursors directly on an insulating TiO 2 substrate only succeeded in deriving polymerization but not the cyclodehydrogenation20.…”

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confidence: 99%

Controllable conversion of quasi-freestanding polymer chains to graphene nanoribbons

Xiao

Zhang

et al. 2017

Nat Commun

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In the bottom-up synthesis of graphene nanoribbons (GNRs) from self-assembled linear polymer intermediates, surface-assisted cyclodehydrogenations usually take place on catalytic metal surfaces. Here we demonstrate the formation of GNRs from quasi-freestanding polymers assisted by hole injections from a scanning tunnelling microscope (STM) tip. While catalytic cyclodehydrogenations typically occur in a domino-like conversion process during the thermal annealing, the hole-injection-assisted reactions happen at selective molecular sites controlled by the STM tip. The charge injections lower the cyclodehydrogenation barrier in the catalyst-free formation of graphitic lattices, and the orbital symmetry conservation rules favour hole rather than electron injections for the GNR formation. The created polymer–GNR intraribbon heterostructures have a type-I energy level alignment and strongly localized interfacial states. This finding points to a new route towards controllable synthesis of freestanding graphitic layers, facilitating the design of on-surface reactions for GNR-based structures.

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On‐Surface Synthesis of Atomically Precise Graphene Nanoribbons

Cited by 441 publications

References 85 publications

Fluorescence from graphene nanoribbons of well-defined structure

Fluorescence from graphene nanoribbons of well-defined structure

Hierarchical on-surface synthesis and electronic structure of carbonyl-functionalized one- and two-dimensional covalent nanoarchitectures

Controllable conversion of quasi-freestanding polymer chains to graphene nanoribbons

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