Surface confined hydrogenation of graphene nanoribbons

Yi-Ying Sung, Harmina Vejayan, Christopher John Baddeley, Federico Grillo, Neville V Richardson, Renald Schaub*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

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Abstract

On-surface synthesis with designer precursor molecules is considered an effective method for preparing graphene nanoribbons (GNRs) of well-defined widths and with tunable electronic properties. Recent reports have shown that the band gap of ribbons doped with heteroatoms (such as boron, nitrogen, and sulfur) remains unchanged in magnitude in most cases. Nevertheless, theory predicts that a tunable band gap may be engineered by hydrogenation, but experimental evidence for this is so far lacking. Herein, surface-confined hydrogenation studies of 7-armchair graphene nanoribbons (7-AGNRs) grown on Au(111) surfaces, in an ultrahigh vacuum environment, are reported. GNRs are first prepared, then hydrogenated by exposure to activated hydrogen atoms. High resolution electron energy loss spectroscopy (HREELS) and scanning tunneling microscopy (STM) images reveal a self-limited hydrogenation process. By means of a combination of bond-resolved scanning tunneling microscopy (BRSTM) imaging and tip-induced site-specific dehydrogenation, the hydrogenation mechanism is studied in detail, and density-functional theory (DFT) calculation methods are used to complement the experimental findings. In all cases, the results demonstrate the successful modification of the electronic properties of the GNR/Au(111) system by edge and basal-plane hydrogenation, and a mechanism for the hydrogenation process is proposed.
Original languageEnglish
Pages (from-to)10281–10291
Number of pages11
JournalACS Nano
Volume16
Issue number7
Early online date5 Jul 2022
DOIs
Publication statusPublished - 26 Jul 2022

Keywords

  • Scanning tunneling spectroscopy
  • Nanoribbons
  • Graphene
  • Hydrogenation
  • Scanning tunneling microscopy

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