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Overview of Carbon Quantum Dots Synthesis Strategies

Carbon quantum dots (CQDs) have attracted much attention since their discovery in 2004[1]. Compared with conventional organic dyes, CQDs have good biocompatibility, good water solubility, fluorescent signal stability, the light can be coordinated, etc. And have been widely researched and applied in biological imaging, biological sensing, optical diagnosis and treatment, photocatalysis, solar cells, light emitting components areas. CQDs is a kind of extremely potential carbon matrix material.

Overview of Carbon Quantum Dots Synthesis Strategies

Overview of Carbon Quantum Dots Synthesis Strategies

At present, the synthesis methods are mainly divided into "top-down" and "bottom-up". The "top-down" synthesis strategy is conducive to the synthesis of carbon quantum dots with high crystalline and complete structure, while the "bottom-up" synthesis strategy usually produces carbon quantum dots with amorphous carbon nuclei, rich doping sites and many surface functional groups.

"Top-down" synthesis strategy

Synthesis strategyAdvantagesDisadvantages
Arc discharge method
  • The earliest method to prepare CDQs
  • Product had good fluorescence properties
  • Production rate is low
  • The purification process is complicated
Electrochemical method
  • The product has good uniformity
  • High utilization rate for carbon source
  • The early processing work is tedious and time-consuming
  • Purification takes a long time
  • The quantum yield is low
Laser ablation
  • Light is adjustable
  • Organic solvents can modify the surface [2]
  • Expensive instrument
  • Complex synthesis
  • Production rate is low
  • Many impurities

"Bottom-up" synthesis strategy

Synthesis strategyAdvantagesDisadvantages
Template method
  • Fluorescence quantum yield is high
  • Uniform particle size distribution
  • Good solubility in water
  • Low biotoxicity
  • Complex preparation steps
Microwave digestion synthesis method
  • Simple and quick operation
  • The particle size distribution of the product is not uniform, and further separation is needed
Ultrasonic oscillation
  • The operation is simple
  • Reaction time is long
  • Production rate is low
Solvent hot method
  • Simple preparation process
  • High yield
  • Organic solvents have certain toxicity
Strong acid oxidation
  • The products all contain carboxyl group, which is favorable for further modification
  • Cumbersome separation steps
  • Uneven particle size
Hydrothermal method
  • The most commonly used preparation method
  • Simple synthesis process
  • Uniform particle size distribution
  • Small toxicity


  • Xu X.; et al. Electrophoretic analysis and purification of fluorescent single-walled carbon nanotube fragments. J.Am.Chem.Soc.2004,126(40):12736- 12737.
  • Hu.; et al. One-step synthesis of fluorescent carbon nanoparticles by laser irradiation. J. Mater. Chem., 2009,19(4):484-488.

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