In Situ Confining Citric Acid-Derived Carbon Dots for Full-Color Room-Temperature Phosphorescence

Area of Science:

• Materials Science
• Nanotechnology
• Photophysics

Background:

• Room-temperature phosphorescence (RTP) is crucial for applications like information encryption and bioelectronics.
• Developing full-color single-component phosphorescent materials presents significant challenges.
• Carbon dots (CDs) are promising candidates for phosphorescent applications due to their unique properties.

Purpose of the Study:

• To develop a facile strategy for synthesizing full-color phosphorescent carbon dots (CDs).
• To investigate the mechanism behind the tunable phosphorescence and long lifetimes of the synthesized CDs.
• To explore the potential applications of these CDs in labeling and information encryption.

Main Methods:

• A novel in situ confining strategy using microwave-assisted carbonization of citric acid in NaOH.
• Tuning the mass ratio of citric acid and NaOH to control the properties of the resulting CDs.
• Characterization of phosphorescence properties (wavelength, lifetime) and synthesis yield.
• Theoretical calculations and experimental validation to understand the emission mechanism.

Main Results:

• Achieved synthesis of full-color phosphorescent CDs with tunable wavelengths from 483 to 635 nm.
• Observed alterable phosphorescence lifetimes ranging from 58 to 389 ms.
• Demonstrated a high synthesis yield of up to 83.7% (>30 g per synthesis).
• Confirmed that high-density ionic bonds and the aggregation state of CDs are key to efficient afterglow emission and redshifted phosphorescence.

Conclusions:

• The proposed in situ confining strategy enables the facile synthesis of full-color phosphorescent CDs.
• The tunable photoluminescence properties are attributed to ionic bonding and controlled aggregation of CDs.
• These findings provide new insights into manipulating RTP in CDs and open avenues for advanced applications.