Carbon Quantum Dots Synthesis and Applications

Carbon quantum dots (CQDs) are quasi-spherical nanoparticles, typically below 10 nm in diameter, that exhibit size- and surface-dependent photoluminescence. Their facile synthesis via top-down approaches (such as laser ablation, arc discharge or electrochemical oxidation) or bottom-up methods (including hydrothermal/solvothermal treatment, microwave pyrolysis and thermal decomposition) affords tunable optical properties, high water dispersibility and abundant surface functional groups. Heteroatom doping and surface passivation strategies further tailor emission wavelengths, quantum yields and electronic structures. CQDs have found wide utility in optoelectronics (light-emitting diodes, lasers), bioimaging and biosensing, photocatalysis and electrocatalysis, as well as in drug delivery and environmental monitoring. Their low cytotoxicity, chemical stability and cost-effective preparation underpin their promise for scalable applications across energy, healthcare and environmental sectors.

Research from Nature Portfolio

Recent studies have achieved exceptionally narrow emission bandwidths and high quantum yields by precise structural control of CQDs. One report demonstrated triangular CQDs with crystalline perfection, yielding narrow full-width at half maximum emissions of ~30 nm and quantum yields up to 72 %, enabling stable multicoloured light-emitting diodes with luminance beyond 1 800 cd m⁻² and high colour purity. Another investigation elucidated the role of edge amino protonation in driving high-colour-purity red fluorescence emission. Through systematic protonation of specific surface moieties, the band gap was tuned to produce 620 nm one-photon and near-infrared two-photon emissions with peak widths below 25 nm, offering a predictive route for customising photoluminescence across the spectrum.

Carbon Quantum Dots Synthesis and Applications publication trend

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

Technical terms

Photoluminescence quantum yield: The ratio of emitted to absorbed photons, indicating the efficiency of fluorescence.

Two-photon fluorescence: Nonlinear emission process in which two lower-energy photons are absorbed simultaneously to excite a fluorophore.

Aggregation-induced emission (AIE): Phenomenon where fluorescence is activated or enhanced upon nanoparticle aggregation due to restricted intramolecular motions.

Heteroatom doping: Incorporation of non-carbon atoms (e.g. N, S) into the carbon lattice to modify electronic and optical properties.

References

1. Engineering triangular carbon quantum dots with unprecedented narrow bandwidth emission for multicolored LEDs. Nature Communications (2018).
2. Photoluminescence mechanism of carbon dots: triggering high-color-purity red fluorescence emission through edge amino protonation. Nature Communications (2021).
3. Graphene Quantum Dot-Mediated Atom-Layer Semiconductor Electrocatalyst for Hydrogen Evolution. Nano-Micro Letters (2023).
4. Rational Design of Multi‐Color‐Emissive Carbon Dots in a Single Reaction System by Hydrothermal. Advanced Science (2020).
5. In vivo theranostics with near-infrared-emitting carbon dots—highly efficient photothermal therapy based on passive targeting after intravenous administration. Light: Science & Applications (2018).