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Updated: Feb 13, 2026

Interfacial Molecular-level Structures of Polymers and Biomacromolecules Revealed via Sum Frequency Generation Vibrational Spectroscopy
Published on: August 13, 2019
Characterisation, coverage, and orientation of functionalised graphene using sum-frequency generation spectroscopy
Huda S AlSalem1, Chloe Holroyd2, Melissa Danial Iswan2
1School of Chemistry, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK and Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK and School of Chemistry, Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia.
Abstract:
We report the unambiguous detection of phenyl groups covalently attached to functionalised graphene using non-linear spectroscopy. Sum-frequency generation was employed to probe graphene on a gold surface after chemical functionalisation using a benzene diazonium salt. We observe a distinct resonance at 3064 cm-1 which can clearly be assigned to an aromatic C-H stretch by comparison with a self-assembled monolayer on a gold substrate formed from benzenethiol. Not only does sum-frequency generation spectroscopy allow one to characterise functionalised graphene with higher sensitivity and much better specificity than many other spectroscopic techniques, but it also opens up the possibility to assess the coverage of graphene with functional groups, and to determine their orientation relative to the graphene surface.
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