Moiré Patterns of Two-Dimensional Covalent Organic Framework Single Crystals Created by Superstacking.
Lezhi Yi1, Yijun Gao1, Chunxing Yan1
1Key Laboratory of Biomedical Polymers Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.
Journal of the American Chemical Society
|August 25, 2025
Summary
This study reveals a novel ABCD stacking mode in two-dimensional (2D) covalent organic frameworks (COFs), COF-400. This stacking behavior was observed in derivatives and Moiré patterns, offering new manipulation possibilities for 2D COFs.
Area of Science:
- Materials Science
- Nanotechnology
- Crystallography
Background:
- Two-dimensional (2D) covalent organic frameworks (COFs) possess unique molecular and crystalline properties.
- Understanding the interlayer stacking of 2D COFs is crucial but remains limited.
Purpose of the Study:
- To report a novel stacking mode in a 2D COF.
- To investigate the structural characteristics of COF-400 and its derivatives.
- To explore the superstacking phenomena and Moiré patterns in exfoliated 2D COF films.
Main Methods:
- Single crystal X-ray and electron diffraction for structural determination.
- Transmission electron microscopy (TEM) for real-space imaging and high-resolution analysis.
- Analysis of Moiré patterns in exfoliated COF films with varying twist angles.
Main Results:
- Discovery of an unprecedented ABCD stacking mode in the 2D COF, COF-400.
- Inheritance of the ABCD stacking mode in reduced (COF-400-Re) and oxidized (COF-400-Ox) derivatives.
- Observation of Moiré patterns in superstacked exfoliated COF films, with clear identification of individual 2D COF single crystals.
Conclusions:
- The findings significantly expand the understanding of 2D COF stacking behaviors.
- The identified stacking modes offer new avenues for manipulating 2D COFs.
- These advancements hold potential for future device fabrication applications.
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