Dye Plants Derived Carbon Dots for Flexible Secure Printing

Area of Science:

• Materials Science
• Nanotechnology
• Organic Chemistry

Background:

• Carbon dots (C-dots) are fluorescent nanomaterials with tunable optical properties.
• Producing high-quality C-dots from sustainable, natural precursors remains a challenge.
• Existing methods often rely on synthetic or less environmentally friendly starting materials.

Purpose of the Study:

• To synthesize multi-colored colloidal carbon dots using natural plant dyes.
• To investigate the optical properties and quantum yield of these C-dots.
• To demonstrate their application in secure printing for anti-counterfeiting.

Main Methods:

• Synthesis of C-dots via a heating reaction using natural plant dyes (Indigo, Carcuma longa, Sophora japonica L.).
• Characterization of optical properties, including UV-Vis absorption and fluorescence emission spectra.
• Evaluation of quantum yield in aqueous solution.
• Application testing as fluorescence inks for textile printing and anti-counterfeiting.

Main Results:

• Successfully synthesized multiple-colored colloidal C-dots from natural plant dyes.
• C-dots exhibit UV absorption (220–450 nm) and broad emission (350–600 nm).
• Achieved a quantum yield of up to 3.8% in aqueous solution.
• Demonstrated effective use as invisible fluorescence inks for textile security printing.

Conclusions:

• Natural plant dyes are viable and eco-friendly precursors for high-performance carbon dots.
• Synthesized C-dots possess excellent optical properties suitable for advanced applications.
• The developed C-dots show significant potential for flexible, optical anti-counterfeiting systems.