Polymerization-Inhibited Twisted Intramolecular Charge Transfer for Strong Molecular Aggregate Emission

Area of Science:

• Materials Science
• Organic Chemistry
• Photophysics

Background:

• Molecular fluorophores with intramolecular charge transfer (ICT) are crucial for tunable fluorescence.
• Twisted intramolecular charge transfer (TICT) states often reduce fluorescence quantum yield.
• Existing methods to suppress TICT are often toxic, costly, and complex.

Purpose of the Study:

• To present a simple and effective strategy to suppress TICT in naphthalimide-based fluorophores.
• To achieve strong molecular emission in aggregate and solid states using polymer chains.
• To develop cost-efficient, highly emissive materials for optoelectronics.

Main Methods:

• Utilizing electron-rich, rigid polymer chains to inhibit TICT.
• Synthesizing naphthalimide-based fluorophores integrated into polymer structures.
• Characterizing photoluminescence properties, including quantum yield and fluorescence lifetime.

Main Results:

• The polymerization-inhibited TICT strategy induced strong aggregation-induced emission (AIE) in resulting oligomers and polymers.
• Achieved high solid-state photoluminescence quantum yields up to 0.80.
• Observed a significant blue shift in emission wavelength and increased fluorescence lifetime, indicating TICT inhibition upon aggregation.

Conclusions:

• Established a cost-efficient and versatile method for developing highly emissive materials.
• Demonstrated the suppression of TICT through polymerization, leading to enhanced solid-state emission.
• The approach shows potential for applications in optoelectronics like luminescent solar concentrators and waveguides.