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17 results on '"Guo, Yunlong"'

4. Fractal Etching of Graphene

Author

Geng, Dechao, Wu, Bin, Guo, Yunlong, Luo, Birong, Xue, Yunzhou, Chen, Jianyi, Yu, Gui, and Liu, Yunqi

Abstract

An anisotropic etching mode is commonly known for perfect crystalline materials, generally leading to simple Euclidean geometric patterns. This principle has also proved to apply to the etching of the thinnest crystalline material, graphene, resulting in hexagonal holes with zigzag edge structures. Here we demonstrate for the first time that the graphene etching mode can deviate significantly from simple anisotropic etching. Using an as-grown graphene film on a liquid copper surface as a model system, we show that the etched graphene pattern can be modulated from a simple hexagonal pattern to complex fractal geometric patterns with sixfold symmetry by varying the Ar/H2flow rate ratio. The etched fractal patterns are formed by the repeated construction of a basic identical motif, and the physical origin of the pattern formation is consistent with a diffusion-controlled process. The fractal etching mode of graphene presents an intriguing case for the fundamental study of material etching.

Published
2024
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5. Isoreticular Covalent Organic Pillars: Engineered Nanotubular Hosts for Tailored Molecular Recognition

Author

Gao, Shengnan, Guo, Yunlong, Xue, Jingfeng, Dong, Xue, Cao, Xiao-Yu, and Sue, Andrew C.-H.

Abstract

In the realm of nanoscale materials design, achieving precise control over the dimensions of nanotubular architectures poses a substantial challenge. In our ongoing pursuit, we have successfully engineered a novel class of single-molecule nanotubes─isoreticular covalent organic pillars (iCOPs)─by stacking formylated macrocycles through multiple dynamic covalent imine bonds, guided by principles of reticular chemistry. Our strategic selection of rigid diamine linkers has facilitated the synthesis of a diverse array of iCOPs, each retaining a homologous structure yet offering distinct cavity shapes influenced by the linker choice. Notably, three of these iCOP variants feature continuous one-dimensional channels, exhibiting length-dependent host–guest interactions with α,ω-dibromoalkanes, and each presenting a distinct critical guest alkyl chain length threshold for efficient guest encapsulation. This newfound capability not only provides a platform for tailoring nanotubular structures with precision, but also opens new avenues for innovative applications in molecular recognition and the purification of complex mixtures.

Published
2024
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14. Fractal Etching of Graphene

Author

Geng, Dechao, primary, Wu, Bin, additional, Guo, Yunlong, additional, Luo, Birong, additional, Xue, Yunzhou, additional, Chen, Jianyi, additional, Yu, Gui, additional, and Liu, Yunqi, additional

Published
2013
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