Proton-Mediated Topological Interlayer Shift in 2D Covalent Organic Frameworks for Efficient Photocatalysis

Area of Science:

• Materials Science
• Chemistry
• Energy Science

Background:

• Interlayer carrier dynamics are crucial for 2D donor-acceptor (D-A) covalent organic frameworks (COFs) in optoelectronics.
• Controlling interlayer interactions in COFs is challenging due to their sensitivity.

Purpose of the Study:

• To demonstrate a proton-mediation strategy for precise regulation of interlayer shift in 2D D-A COFs.
• To facilitate charge transfer and exciton dissociation by controlling COF stacking.

Main Methods:

• Proton-mediation strategy applied to three imine-linked D-A COFs (IMDA).
• Analysis of interlayer stacking (eclipsed AA vs. slipped AA) and its effect on D-A pair orientation and π-conjugation.
• Evaluation of charge transfer dynamics, exciton binding energy, and interlayer exciton dissociation.

Main Results:

• Mild proton-mediation yields eclipsed AA stacking (IMDA-AA) with in-plane D-A pairs and overlapping π-conjugations.
• Excessive proton-mediation leads to slipped AA stacking (IMDA-SAA) with out-of-plane D-A pairs.
• Eclipsed AA stacking (IMDA-AA) optimizes charge transfer, reduces exciton binding energy, and boosts exciton dissociation.

Conclusions:

• Proton-mediation offers precise control over COF interlayer topology and charge transfer dynamics.
• IMDA-AA COF achieved a record hydrogen evolution rate of 171.2 mmol g⁻¹h⁻¹ under visible light.
• This work provides a pathway for topology-governed charge transfer in COFs for enhanced solar energy conversion.