Uncovering Aggregation-Induced Emission in Carbon Dots for Color-Changing Hydrogels and Information Encryption

Area of Science:

• Materials Science
• Nanotechnology
• Photochemistry

Background:

• Carbon dots (CDs) are widely studied nanomaterials.
• Citric acid (CA) and urea are common precursors for CD synthesis.
• Aggregation-induced emission (AIE) in CDs is an emerging research area.

Purpose of the Study:

• To synthesize red-emissive carbon dots (R-CDs) using citric acid and urea.
• To investigate the aggregation-induced emission (AIE) properties of the synthesized R-CDs.
• To explore the solvent-responsive photoluminescence behavior and potential applications of R-CDs.

Main Methods:

• Hydrophilic red-emissive carbon dots (R-CDs) were synthesized using citric acid and urea.
• Photoluminescence properties were studied in different solvent polarities (water vs. DMF).
• Anticounterfeiting and information encryption applications were demonstrated, alongside hydrogel fabrication with PVA.

Main Results:

• Synthesized R-CDs exhibit blue fluorescence in water (dispersed) and red fluorescence in DMF (aggregated).
• Photoluminescence is governed by π-π stacking and solvent effects, leading to solvent-responsive emission.
• Successful demonstration of anticounterfeiting, information encryption, and hydrogel-based fluorescent materials.

Conclusions:

• Citric acid-urea derived R-CDs show tunable AIE properties.
• Solvent polarity significantly influences R-CD photoluminescence via intermolecular interactions.
• R-CDs are promising for advanced functional materials like anticounterfeiting and information encoding.