Triphenylamine-Based Covalent Organic Framework Films for Dopamine-Responsive Electrofluorochromism

Area of Science:

• Materials Science
• Organic Chemistry
• Electrochemistry

Background:

• Covalent Organic Frameworks (COFs) are crystalline porous polymers with tunable properties.
• Electrochromic (EC) and electrofluorochromic (EFC) materials change color or fluorescence upon electrical stimulation.
• Developing bifunctional materials with both EC and EFC properties is crucial for advanced optoelectronics.

Purpose of the Study:

• To synthesize and characterize a novel COF film exhibiting both electrofluorochromic (EFC) and electrochromic (EC) properties.
• To investigate the performance of the COF film in terms of fluorescence and color switching, contrast, and response times.
• To explore the potential of the bifunctional COF film in constructing logic gates.

Main Methods:

• Synthesis of a COF film using triphenylamine-based monomers.
• Electrochemical characterization of EFC and EC properties, including fluorescence contrast, color contrast, and switching times.
• Investigation of fluorescence restoration using dopamine as a reductant.
• Demonstration of a NAND logic gate utilizing applied potential and dopamine addition.

Main Results:

• The COF film achieved a high maximum fluorescence contrast of 151 (EFC "off" state) at 0.75 V, with switching times of 0.51 s (on) and 7.79 s (off).
• The film displayed EC properties with a contrast of 50.23% at 532 nm and a coloration efficiency of 297.4 cm2 C-1, with switching times of 18.6 s (coloration) and 0.7 s (bleaching).
• Dopamine addition restored the quenched fluorescence, enabling the creation of a NAND logic gate with dual physical and chemical inputs.

Conclusions:

• Successful synthesis of a bifunctional COF film with simultaneous EFC and EC properties.
• Demonstrated high performance in both fluorescence and color switching, indicating potential for optoelectronic applications.
• Established the feasibility of using the COF film for logic gate implementation, highlighting its versatility.