σ-π Hyperconjugation as a Design Strategy for High-Performance Fluorescent Covalent Organic Frameworks

Area of Science:

• Materials Science
• Optoelectronics
• Organic Chemistry

Background:

• Achieving efficient solid-state fluorescence in covalent organic frameworks (COFs) is a significant challenge for optoelectronic applications.
• Existing COFs often suffer from low fluorescence quantum yields, limiting their practical use.

Purpose of the Study:

• To develop a novel strategy for enhancing the fluorescence properties of COFs.
• To explore the application of σ-π hyperconjugation in modulating COF optoelectronic performance.
• To demonstrate a practical application of enhanced COFs in sensing technology.

Main Methods:

• Incorporation of methyl groups into pyrene-based COF monomers to induce σ-π hyperconjugation.
• Fabrication of COF-based fluorescent acoustic sensors using electrospinning.
• Integration of sensors with machine learning algorithms for speech pattern recognition.

Main Results:

• A >100-fold increase in fluorescence quantum yield was achieved in the modified pyrene-based COF.
• σ-π hyperconjugation was confirmed to redistribute electron density, altering pyrene's electronic properties.
• The developed COF sensor demonstrated real-time speech pattern recognition capabilities.

Conclusions:

• σ-π hyperconjugation offers a powerful method for precise optoelectronic property modulation in COFs.
• This approach significantly enhances fluorescence and performance, overcoming previous limitations.
• COF-based sensors show promise for developing advanced language-assistive technologies.