Fe-Doped 4-Aminophenylacetylene-Derived Red Emissive Polymer Carbon Dots: Synthesis and Anti-Counterfeiting...

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Phenylacetylene derivatives are key monomers for polyaddition reactions.
• Controlling the structure and optical properties of polymers is crucial for advanced applications.

Purpose of the Study:

• To develop a straightforward one-step protocol for synthesizing iron-doped polyacetylene and carbonized polymer dots (CPDs-Fe).
• To investigate the effect of iron(III) doping concentration and reaction conditions on the structural and photonic properties of the synthesized materials.
• To explore the potential of the resulting materials in fluorescence and phosphorescence-based technologies, including anti-counterfeiting.

Main Methods:

• One-step solvothermal addition and carbonization of 4-aminophenylacetylene with varying Fe³⁺ concentrations in ethanol at 200 °C.
• Characterization using luminescence spectroscopy, quantum yield measurements, and structural/morphological analyses (e.g., X-ray diffraction, electron microscopy).
• Density Functional Theory (DFT) calculations to understand the electronic structure and emission mechanisms.
• Fabrication of a CPDs-Fe@poly(vinyl alcohol) composite film for application testing.

Main Results:

• Synthesis of undoped polyacetylene (P0), doped polyacetylene (P0.09), and iron-doped carbonized polymer dots (CPDs-Fe).
• Tuning of luminescence from green (P0, λmax = 514 nm, QY = 20.08%) to red (CPDs-Fe, λmax = 645 nm, QY = 9.03%) with increasing Fe³⁺ doping.
• Structural transformation from amorphous to highly crystalline with increasing conjugation length upon Fe³⁺ doping and carbonization.
• CPDs-Fe@PVA films exhibit dual-mode fluorescence and room-temperature phosphorescence with tunable lifetimes.

Conclusions:

• A facile method was established to synthesize tunable carbonized polymer dots with tailored structural and photonic properties.
• Fe³⁺ doping and carbonization significantly influence conjugation, band gap, and emission color, enabling red-shifted luminescence.
• The developed CPDs-Fe materials show promise for anti-counterfeiting and other fluorescence/phosphorescence-based applications.