Chiral Covalent Organic Framework Films with Enhanced Photoelectrical Performances.

Area of Science:

• Materials Science
• Nanotechnology
• Chemistry

Background:

• Two-dimensional covalent organic frameworks (2D COFs) offer potential for optoelectrical applications, but stacking deviations limit their performance.
• Achieving controlled out-of-plane charge transfer in 2D COFs is crucial for maximizing their functionality.

Purpose of the Study:

• To develop a chirality-induced strategy for controlling the parallel AA-stacking sequence in 2D COF films.
• To investigate the impact of controlled stacking on the optoelectrical properties of COFs.

Main Methods:

• Fabrication of β-ketoenamine-linked COF films on FTO substrates.
• Incorporation of chiral modules at framework nodes to direct parallel AA-stacking.
• Characterization of optoelectrical properties, including photocurrent response and charge carrier dynamics.

Main Results:

• The chiral strategy successfully achieved periodic parallel AA-stacking with identical mirrored configurations.
• The resulting chiral COF films exhibited prolonged charge carrier lifetime and fast charge-transfer dynamics.
• An ultrahigh electron collection efficiency led to an excellent photocurrent response of 38 μA/cm² at 0.25 V (vs RHE).

Conclusions:

• Controlled stacking via chiral nanoarchitectonics significantly enhances photoinduced electron-hole dissociation and charge transfer.
• Chiral COFs demonstrate superior optoelectrical performance compared to achiral analogues.
• This approach holds great promise for advancing chiral COFs in photoelectrical catalysis.