Size‐Dependent Evolution of Graphene Nanopores Under Thermal Excitation

Xu, Tao; Yin, Kuibo; Xie, Xiaoguang; He, Longbing; Wang, Binjie; Sun, Litao

doi:10.1002/smll.201200979

Cited by 54 publications

(45 citation statements)

References 26 publications

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“…Taken together, the N‐GQDs preferred to form curved peripheries in thermodynamically equilibrium structures of circle or ellipse to minimize edge free energies, through migration of uncombined C atoms, rearrangement of atoms (C, N, O, etc. ), and/or reconstruction of crystallization . The edge structures are the essential features of graphene, including zigzag‐ or armchair‐edge configurations .…”

Section: Resultsmentioning

confidence: 99%

Versatile Graphene Quantum Dots with Tunable Nitrogen Doping

Dai

Huan

Wang

et al. 2013

Part & Part Syst Charact

139

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This paper reports a facile fabrication of N‐doped graphene quantum dots (N‐GQDs) showing controllable chemical properties through a hydrothermal treatment. The N‐GQDs have a uniform size of 3.06 ± 0.78 nm and prefer the equilibrium shapes of circle and ellipse due to the minimization of edge free energy. The N/C atomic ratio in N‐GQDs can be precisely tailored in a range from 8.3 at% to 15.8 at% by simply controlling the concentration of N source (ammonium hydroxide). One order of magnitude quantum yield of 34.5% is achieved by N‐GQDs, compared with the N‐free GQDs, as the substitutional N has an essential role in more effective radiative emission. Excessive N dopants in N‐GQDs can lead to photoluminescence quenching, through nonradiative transition back to the ground state. The N‐GQDs are further found to be suitable as photocurrent conversion materials due to benign energy matching with anatase nanofibers, the ultrafast electron injection at their interface, and efficient electron transfer. This work provides an efficient and inspiring approach to engineering both chemical components and physical properties of N‐GQDs, and will therefore promote their basic research and applications in energy conversion.

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Section: Resultsmentioning

confidence: 99%

Versatile Graphene Quantum Dots with Tunable Nitrogen Doping

Dai

Huan

Wang

et al. 2013

Part & Part Syst Charact

139

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“…When the electron beam density is larger than the threshold, the carbon atoms are sculpted . Xu et al further demonstrated the evolution process of graphene nanopores under thermal stress . They simplified the nanopore as a cylinder and found that their thermally induced evolution is dependent on the relationship between graphene thickness and the diameter of the graphene nanopore by calculating the free surface energy.…”

Section: Selectively Permeable 2d Materials Membranesmentioning

confidence: 99%

Two‐Dimensional Material Membranes: An Emerging Platform for Controllable Mass Transport Applications

Zhao

Xie

Liu

et al. 2014

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129

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Two-dimensional materials provide an ideal platform for studying the fundamental properties of atomic-level thickness systems, and are appropriate for lots of engineering applications in various fields. Although 2D materials are the thinnest membranes, they have been revealed to have high impermeability even to the smallest molecule. By the virtue of this high impermeability of the 2D materials in combination with their other unique properties, 2D materials open up a variety of applications that are impossible for conventional membranes. In this review, the latest applications based on high impermeability and selective permeation of these 2D material membranes are overviewed for different fields, including environmental control, chemical engineering, electronic devices, and biosensors. The working mechanism for each kind of application is described in detail. A summary and outlook is then provided on the challenges and new directions in this emerging research field.

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“…Thermal excitation can be adopted to modulate the size of as‐fabricated pores, as it promotes the migration and reconstruction of defects. Consequently, graphene nanopores could shrink or expand by direct thermal excitation, depending on the ratio of nanopore diameter to membrane thickness, thereby making the electron beam‐based fabrication much more controllable …”

Section: Nanofabrication With Atomic Resolutionmentioning

confidence: 99%

Dynamic In‐Situ Experimentation on Nanomaterials at the Atomic Scale

Sun

2015

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With the development of in situ techniques inside transmission electron microscopes (TEMs), external fields and probes can be applied to the specimen. This development transforms the TEM specimen chamber into a nanolab, in which reactions, structures, and properties can be activated or altered at the nanoscale, and all processes can be simultaneously recorded in real time with atomic resolution. Consequently, the capabilities of TEM are extended beyond static structural characterization to the dynamic observation of the changes in specimen structures or properties in response to environmental stimuli. This extension introduces new possibilities for understanding the relationships between structures, unique properties, and functions of nanomaterials at the atomic scale. Based on the idea of setting up a nanolab inside a TEM, tactics for design of in situ experiments inside the machine, as well as corresponding examples in nanomaterial research, including in situ growth, nanofabrication with atomic precision, in situ property characterization, and nanodevice construction are presented.

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Size‐Dependent Evolution of Graphene Nanopores Under Thermal Excitation

Cited by 54 publications

References 26 publications

Versatile Graphene Quantum Dots with Tunable Nitrogen Doping

Versatile Graphene Quantum Dots with Tunable Nitrogen Doping

Two‐Dimensional Material Membranes: An Emerging Platform for Controllable Mass Transport Applications

Dynamic In‐Situ Experimentation on Nanomaterials at the Atomic Scale

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