Synthesis and Characterization of Graphene Nanostructures

Graphene nanostructures encompass a diverse class of materials, including narrow ribbons, oxide derivatives and quantum dots, whose exceptional electrical, mechanical and optical properties derive from their two-dimensional carbon lattice and size-constrained geometries. Synthesis strategies span top-down routes—such as longitudinal unzipping of carbon nanotubes via chemical or hydrothermal treatments—and bottom-up approaches, including chemical vapour deposition and epitaxial growth on catalytic substrates. Characterisation techniques, notably Raman spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and atomic force microscopy, elucidate layer number, edge structure, defect density and functional group distribution. Tunable band gaps, high carrier mobility and surface chemistry have enabled applications in nanoelectronics, energy storage, sensing, catalysis and composite reinforcement, with a growing emphasis on scalable, green processes and integration into practical devices.

Research from Nature Portfolio

Recent studies have advanced intercalation-assisted unzipping to produce high-quality graphene nanoribbons (GNRs) at scale. One approach employs potassium nitrate and sulphuric acid to intercalate multi-walled carbon nanotubes (MWCNTs), weakening van der Waals forces and enabling environmentally benign longitudinal cleavage. Characterisation by Raman spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy confirms effective ion penetration and improved GNR yield under mild conditions. A complementary hydrothermal technique utilises sulphate and nitrate counter-ions in aqueous media to exfoliate MWCNTs, yielding conductive and transparent GNR films with over 80% efficiency and sheet resistances around 16 kΩ sq⁻¹. This cooperative ion mechanism offers precise control over ribbon width and electronic properties, highlighting routes towards industrially viable production.

Synthesis and Characterization of Graphene Nanostructures publication trend

The graph below shows the total number of articles in synthesis and characterization of graphene nanostructures across all publications each year (not limited to Nature Index journals).

Technical terms

Graphene nanoribbon (GNR): A narrow strip of graphene, typically less than 50 nm wide, whose edge structure governs its electronic band gap and transport characteristics.

Intercalation: The insertion of ions or molecules between the layers of a layered material to weaken interlayer interactions and facilitate exfoliation.

Unzipping: The longitudinal cleavage of carbon nanotubes into flat graphene ribbons by chemical, hydrothermal or mechanical means.

Hydrothermal synthesis: A method employing aqueous solutions at elevated temperatures and pressures to drive chemical transformations and material exfoliation.

Photoluminescence: The emission of light from a material after absorption of photons, indicative of its electronic structure and defect states.

References

1. Intercalation-assisted longitudinal unzipping of carbon nanotubes for green and scalable synthesis of graphene nanoribbons. Scientific Reports (2016).
2. Counter-ion Dependent, Longitudinal Unzipping of Multi-Walled Carbon Nanotubes to Highly Conductive and Transparent Graphene Nanoribbons. Scientific Reports (2014).
3. Recent progress and future perspectives on graphene oxide nanoribbons: Dispersion, structure assembly, and applications. APL Materials (2022).
4. Hydrothermal Unzipping of Multiwalled Carbon Nanotubes and Cutting of Graphene by Potassium Superoxide. Nanomaterials (2022).
5. Self-Photoluminescence of Unzipped Multi-Walled Carbon Nanotubes. Nanomaterials (2021).