Carbon Dots (CDs) and Graphene Quantum Dots (GQDs)

Carbon Dots (CDs) and Graphene Quantum Dots (GQDs) there characteristics, Synthesis, Difference Between them and Applications

Carbon Dots (CDs) and Graphene Quantum Dots (GQDs) are both nanoscale carbon-based materials with unique properties and applications. Here's a concise overview of their characteristics, synthesis methods, differences, and applications:

 

Characteristics:

1. Carbon Dots (CDs):

·        Small carbon nanoparticles typically less than 10 nm in size.

·        Composed of amorphous carbon structures with surface passivation by functional groups.

·        Wide range of fluorescence emission, high photostability, and biocompatibility.

 

2. Graphene Quantum Dots (GQDs):

·        Small graphene fragments with lateral dimensions usually less than 100 nm.

·        Atomically thin sheets of sp²-hybridized carbon atoms arranged in a honeycomb lattice.

·        Quantum confinement effect leads to tunable optical and electronic properties.

 

Synthesis:

Carbon Dots (CDs): CDs can be synthesized through various methods, including hydrothermal/solvothermal methods, microwave-assisted pyrolysis, and laser ablation. Precursors commonly used include carbon-containing precursors like citric acid, glucose, and carbon nanotubes.

 

Graphene Quantum Dots (GQDs): GQDs can be synthesized by bottom-up or top-down approaches. Bottom-up methods involve the controlled growth of graphene nanosheets using chemical vapor deposition or epitaxial growth, followed by fragmentation. Top-down methods involve the exfoliation or cutting of bulk graphene into smaller fragments through chemical or mechanical processes.

 

Differences in CDs and GQDs:

Structure: CDs are amorphous carbon nanoparticles, while GQDs are fragments of graphene sheets.

Size: CDs are typically less than 10 nm in size, while GQDs have lateral dimensions usually less than 100 nm.

Properties: CDs exhibit fluorescence emission and can have various surface passivation groups, while GQDs show quantum confinement effects and unique optical/electronic properties.

Both CDs and GQDs hold great promise for a wide range of applications due to their unique properties and versatility in synthesis methods.

 Applications of CDs/GQDs:

·        Fluorescent probes for bioimaging and sensing applications.

·        Energy-related applications like solar cells, supercapacitors, and photocatalysis.

·        Drug delivery systems and bio-medicine applications.

·        Optoelectronic devices, such as photodetectors, light-emitting diodes (LEDs), and solar cells.

·        Energy storage devices like supercapacitors and batteries.

Catalysts for various chemical reactions and sensors.

References:

1. Recent advancement in bio-precursor derived graphene quantum dots: synthesis, characterization and toxicological perspective
2. Green synthesis of fluorescent graphene quantum dots and its application in selective curcumin detection
3. Fabrication of poly (aspartic) acid functionalized graphene quantum dots based FRET sensor for selective and sensitive detection of MAGE-A11 antigen