Strategy to Synthesize Tunable Multiemission Carbon Dots and Their Multicolor Visualization Application

Area of Science:

• Materials Science
• Nanotechnology
• Photochemistry

Background:

• Multiemission fluorescent carbon dots (CDs) offer label-free, multicolor visualization and resist background interference.
• Understanding the link between precursor materials and luminescence is crucial for developing advanced CDs.
• Existing multiemission CDs often lack tunable optical properties and versatile applications.

Purpose of the Study:

• To develop novel multiemission carbon dots (M-CDs) using a template strategy with fluorescent precursors.
• To investigate the relationship between precursor substances and the origins of luminescence in M-CDs.
• To explore the potential of M-CDs for pH sensing and cell imaging.

Main Methods:

• Synthesized M-CDs using calcein as a fluorescent precursor via a template strategy.
• Investigated luminescence origins by analyzing contributions from solvent, surface defects, and precursor luminophores.
• Optimized M-CD optical properties by adjusting NaOH concentration and solvothermal synthesis time.
• Developed a multicolor sensor using M-CDs and rhodamine B (RhB) for pH detection and cell imaging.

Main Results:

• Calcein-derived M-CDs exhibited three distinct emissions in UV, blue, and green regions.
• Tunable optical properties were achieved by modifying synthesis parameters (NaOH, time).
• The M-CDs demonstrated a linear fluorescence response to pH variations, enabling multicolor evolution.
• Successfully applied the M-CD-based sensor for cell imaging.

Conclusions:

• A novel template strategy successfully produced multiemission carbon dots with tunable fluorescence.
• The study elucidated the luminescence mechanisms originating from solvent, defects, and precursor structures.
• The developed M-CDs show significant promise for advanced applications in pH sensing and bioimaging.