Near–atomic-scale observation ofgrain boundaries inalayer-stacked two-dimensional polymer

Qi, Haoyuan; Sahabudeen, Hafeesudeen; Liang, Baokun; Položij, Miroslav; Addicoat, Matthew A.; Gorelik, Tatiana E.; Hambsch, Mike; Mundszinger, Manuel; Park, SangWook; Lotsch, Bettina V.; Mannsfeld, Stefan C.B.; Zheng, Zhikun; Dong, Renhao; Heine, T.; Feng, Xinliang and Kaiser, Ute (2020): Near–atomic-scale observation ofgrain boundaries inalayer-stacked two-dimensional polymer. In: Science Advances, Vol. 6, No. 33

Abstract

Two-dimensional (2D) polymers hold great promise in the rational materials design tailored for next-generation applications. However, little is known about the grain boundaries in 2D polymers, not to mention their formation mechanisms and potential influences on the material’s functionalities. Using aberration-corrected high-resolution transmission electron microscopy, we present a direct observation of the grain boundaries in a layer-stacked 2D polyimine with a resolution of 2.3 Å, shedding light on their formation mechanisms. We found that the polyimine growth followed a “birth-and-spread” mechanism. Antiphase boundaries implemented a self-correction to the missing-linker and missing-node defects, and tilt boundaries were formed via grain coalescence. Notably, we identified grain boundary reconstructions featuring closed rings at tilt boundaries. Quantum mechanical calculations revealed that boundary reconstruction is energetically allowed and can be generalized into different 2D polymer systems. We envisage that these results may open up the opportunity for future investigations on defect-property correlations in 2D polymers.

• Item Type: Journal article
• EU Funded Grant Agreement Number: 639233
• EU Projects: Horizon 2020 > ERC Grants > ERC Starting Grant > ERC Grant 639233: Fuel from sunlight: Covalent organic frameworks as integrated platforms for photocatalytic water splitting and CO2 reduction; Horizon 2020
• Form of publication: Publisher's Version
• Faculties: Chemistry and Pharmacy > Department of Chemistry
• Subjects: 500 Science > 540 Chemistry
• ISSN: 2375-2548
• Language: English