Red-Emissive Center Formation within Carbon Dots Based on Citric Acid and Formamide

Area of Science:

• Materials Science
• Nanotechnology
• Photochemistry

Background:

• Carbon dots (CDs) are versatile nanomaterials with tunable optical properties.
• Red-emissive CDs are particularly valuable for bioimaging and sensing applications.
• Current synthesis methods often suffer from low yields and byproduct formation.

Purpose of the Study:

• To investigate the formation of red-emissive optical centers in carbon dots.
• To optimize synthesis parameters, specifically the molar ratio of citric acid to formamide.
• To maximize the chemical yield and quantum yield of red-emissive CDs while minimizing byproducts.

Main Methods:

• Systematic variation of precursor (citric acid and formamide) amounts.
• Synthesis of carbon dots using a hydrothermal method.
• Characterization of optical properties, including emission wavelength and quantum yield.
• Analysis of chemical yield and byproduct formation.

Main Results:

• Red emission centered at 640 nm upon excitation at 590 nm was achieved.
• An optimal molar ratio of citric acid to formamide of 1:4 was identified.
• A high chemical yield of 26% for carbon dots was obtained.
• Quantum yield reached up to 19%.

Conclusions:

• The molar ratio of precursors is critical for controlling the formation of red-emissive optical centers in carbon dots.
• The optimized synthesis provides a high yield of red-emissive carbon dots with good quantum efficiency.
• This work offers a pathway for efficient and scalable production of red-emissive carbon dots.