Modulating Optoelectronic Properties of TBQP-Based Covalent Organic Frameworks for Chemical Sensing

Area of Science:

• Materials Science
• Computational Chemistry
• Chemical Engineering

Background:

• Covalent organic frameworks (COFs) are promising porous organic semiconductors for chemical sensing.
• Understanding how molecular functionalization impacts COF optoelectronic properties is crucial for rational design.

Purpose of the Study:

• To computationally investigate the effect of edge functionalization on TBQP-based COFs.
• To establish structure-property relationships linking molecular modification to optoelectronic behavior and sensing performance.

Main Methods:

• Density Functional Theory (DFT) and molecular dynamics simulations were employed.
• Analysis of electronic structure, optical properties, and adsorption reactivity towards Cl2, ClF3, and SO2.
• Correlation of experimental Hammett parameters with DFT-based reactivity indices.

Main Results:

• Frontier orbital energies and band gap are governed by the electronic character of building blocks, allowing property modulation via substituents.
• Quantitative correlations were established between chemical modification and optoelectronic behavior.
• Analyte adsorption induces midgap states, indicating a general electronic sensing mechanism for π-conjugated COFs.

Conclusions:

• Molecular functionalization is critical for tailoring the electronic and reactive properties of TBQP frameworks.
• The study provides guidelines for designing COF-based chemical sensors with enhanced performance.
• Identified structure-property relationships facilitate the rational design of porous organic semiconductor sensors.