Graphene Quantum Dots: Synthesis and Applications

Graphene quantum dots (GQDs) represent a class of zero-dimensional nanomaterials derived from graphene with dimensions typically below 20 nm. Their reduced size induces a non-zero bandgap and strong quantum confinement effects, endowing them with tunable photoluminescence, high surface area and exceptional chemical stability. Synthesis methods broadly fall into two categories: top-down approaches, which fragment larger carbon sources such as graphene oxide via oxidative cutting or laser ablation, and bottom-up approaches from molecular precursors through pyrolysis or hydrothermal routes. Surface functionalisation and heteroatom doping further modulate optical, electrical and catalytic properties, enabling precise control over quantum yield and emission wavelength. Owing to their biocompatibility, low toxicity and versatile processing, GQDs have found applications across diverse fields. In optoelectronics, they serve as fluorescent inks, light-emitting diodes and photodetectors. In biomedicine, they function as imaging probes and drug-delivery vehicles. In energy and sensing, they enhance the performance of batteries, supercapacitors and electrochemical sensors. Recent advances have focused on scalable, green synthesis techniques and integration into functional composites to unlock their global potential for sustainable technology and healthcare.

Research from Nature Portfolio

Recent studies have demonstrated high-yield, green routes for GQD production using renewable biomass. Microwave-assisted oxidative cutting of carbonaceous precursors achieved yields exceeding 80%, producing hydrophilic GQDs with excitation-independent photoluminescence and quantum yields around 23%. These materials were applied in highly selective sensors for ferric ions, achieving detection limits in the micromolar range. In parallel, a one-pot exfoliation and disintegration approach generated both hydrophilic and hydrophobic nitrogen-doped GQDs. The hydrophilic variant showed excellent biocompatibility, high photoluminescence quantum yield and stability for cellular imaging, while the hydrophobic form yielded composite electrodes with enhanced areal capacitance for supercapacitors. Such work underscores the feasibility of synchronised production of functionalised GQDs and their seamless integration into devices.

Graphene Quantum Dots: Synthesis and Applications publication trend

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

Technical terms

Graphene quantum dots (GQDs): Nanoscale fragments of graphene with dimensions below 20 nm exhibiting discrete electronic states due to quantum confinement.

Quantum confinement: Spatial restriction of charge carriers in nanoscale materials leading to discrete energy levels and tunable optical properties.

Top-down synthesis: Production of GQDs by cleaving larger carbon structures, such as graphene oxide, via oxidative cutting or physical methods.

Bottom-up synthesis: Assembly of GQDs from molecular precursors through reactions like pyrolysis or hydrothermal treatment.

Heteroatom doping: Introduction of non-carbon atoms (e.g. nitrogen, sulphur) into the graphene lattice to modify electronic and optical characteristics.

Photoluminescence: Emission of light from a material upon absorption of photons, a key feature exploited in imaging, sensing and optoelectronics.

References

1. High yield synthesis of graphene quantum dots from biomass waste as a highly selective probe for Fe3+ sensing. Scientific Reports (2020).
2. One-Pot Synthesis of Hydrophilic and Hydrophobic N-Doped Graphene Quantum Dots via Exfoliating and Disintegrating Graphite Flakes. Scientific Reports (2016).
3. Graphene Quantum Dots Electrochemistry and Sensitive Electrocatalytic Glucose Sensor Development. Nanomaterials (2017).
4. Graphene Quantum Dots by Eco-Friendly Green Synthesis for Electrochemical Sensing: Recent Advances and Future Perspectives. Nanomaterials (2021).