Flexible Graphene Films via the Filtration of Water-Soluble Noncovalent Functionalized Graphene Sheets

Xu, Yuxi; Bai, Hua; Lu, Gewu; Li, Chun; Shi, Gaoquan

doi:10.1021/ja800745y

Cited by 3,109 publications

(2,002 citation statements)

References 23 publications

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“…To obtain unoxidized GNRs, we employ the superacid-based-exfoliation strategy (80% efficiency, Supplementary Fig. S1e) 29 , where the superacid quenches the π-π interaction between the graphene sheets. The automated nanotome produces one HOPG cut per second.…”

Section: Exfoliationmentioning

confidence: 99%

Nanotomy-based production of transferable and dispersible graphene nanostructures of controlled shape and size

et al. 2012

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Because of the edge states and quantum confinement, the shape and size of graphene nanostructures dictate their electrical, optical, magnetic and chemical properties. The current synthesis methods for graphene nanostructures do not produce large quantities of graphene nanostructures that are easily transferable to different substrates/solvents, do not produce graphene nanostructures of different and controlled shapes, or do not allow control of Gn dimensions over a wide range (up to 100 nm). Here we report the production of graphene nanostructures with predetermined shapes (square, rectangle, triangle and ribbon) and controlled dimensions. This is achieved by diamond-edge-induced nanotomy (nanoscalecutting) of graphite into graphite nanoblocks, which are then exfoliated. our results show that the edges of the produced graphene nanostructures are straight and relatively smooth with an I D /I G of 0.22-0.28 and roughness < 1 nm. Further, thin films of Gn-ribbons exhibit a bandgap evolution with width reduction (0, 10 and ~35 meV for 50, 25 and 15 nm, respectively).

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Section: Exfoliationmentioning

confidence: 99%

Nanotomy-based production of transferable and dispersible graphene nanostructures of controlled shape and size

et al. 2012

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“…E xfoliation of layered materials in solution leads to dispersed single or few atomic/molecular layers that can be readily reassembled into paper-like films by filtration or casting [1][2][3][4][5] . The resulting films usually have a lamellar microstructure due to stacking of the high aspect ratio two-dimensional (2D) sheets.…”

mentioning

confidence: 99%

Self-assembled two-dimensional nanofluidic proton channels with high thermal stability

et al. 2015

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Exfoliated two-dimensional (2D) sheets can readily stack to form flexible, free-standing films with lamellar microstructure. The interlayer spaces in such lamellar films form a percolated network of molecularly sized, 2D nanochannels that could be used to regulate molecular transport. Here we report self-assembled clay-based 2D nanofluidic channels with surface charge-governed proton conductivity. Proton conductivity of these 2D channels exceeds that of acid solution for concentrations up to 0.1 M, and remains stable as the reservoir concentration is varied by orders of magnitude. Proton transport occurs through a Grotthuss mechanism, with activation energy and mobility of 0.19 eV and 1.2 Â 10 À 3 cm 2 V À 1 s À 1 , respectively. Vermiculite nanochannels exhibit extraordinary thermal stability, maintaining their proton conduction functions even after annealing at 500°C in air. The ease of constructing massive arrays of stable 2D nanochannels without lithography should prove useful to the study of confined ionic transport, and will enable new ionic device designs.

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“…GO was synthesized by using a modified Hummers method as described in previous reports. [7][8]27] The AOG and GO dispersions were centrifuged at 12 000 rpm for 10 min to remove the unexfoliated content. The supernatants were used for the following experiments and the concentration of AOG or GO was determined by UV/Vis absorption spectrometry.…”

Section: Methodsmentioning

confidence: 99%

Mildly Oxidized Graphene: Facile Synthesis, Characterization, and Application as a Matrix in MALDI Mass Spectrometry

Liu

Cheng

Jiang

2013

Chemistry A European J

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Graphene (G) is a new allotropic member of carbon with a unique two-dimensional and one-atom-thick sheet structure. It has attracted tremendous research interest in both academic and industrial areas due to its exceptional physical and chemical properties. [1][2][3] However, a serious problem in synthesis and application of G is aggregation. Due to the strong hydrophobic nature of G, G sheets have a strong tendency to aggregate to G clusters or even restack to graphite particles through van der Waals interactions. The resulting G agglomerates are very hard and insoluble in water or organic solvents, making further processing difficult. Since most of the exceptional properties of G can only be achieved with individual sheets, prevention of aggregation of G sheets is of particular importance for its applications.Aggregation of G can be reduced by using stabilizers. [4][5][6] However, attachment of foreign molecules onto G sheets may cause an adverse impact on the applications. As an alternative, graphene oxide (GO) has an excellent water dispersibility and has been used as a substitute for G in many applications. [3] GO is usually obtained by exfoliation of graphite oxide, [7][8] which can be synthesized from graphite. [9] However, the heavy oxidation during the synthesis can severely damage the large delocalized p-electron system of G and cause many imperfections and defects in the GO sheets. Thus, the unique electronic and optical absorption properties of G are seriously compromised in GO. Li et al. [10] reported the preparation of a processable aqueous dispersion of chemically converted G from GO; however, the obtained G dispersion was only stable under basic conditions and the reductant was difficult to remove from the dispersion. Therefore, facile and scalable methods for the synthesis of low-defect, well-dispersed, and clean G sheets are still urgently desired. Inspired by GO, we hypothesized that controlling the oxidation degree of G may provide a feasible approach for this purpose. However, although significant efforts have been made on developing synthetic strategies of G, little attention has been paid to controlling the oxidation degree of G. [11][12] Herein, we report a very simple method for the synthesis of mildly oxidized graphene by oxidizing chemically converted G with diluted nitric acid (2 m; Scheme 1A). We aimed to find a facile approach to prevent the aggregation of G sheets while maintaining the G structure as intact as possible. To distinguish from GO, the produced material is called acid-oxidized graphene (AOG). The AOG showed good dispersibility in water (up to 1 mg mL À1 ). Meanwhile, unlike GO (Scheme 1B), the main framework of G was not disrupted, and thus most of the exceptional properties of G can be maintained. Therefore, the AOG combines the advantages of G and GO while avoiding their disadvantages. Furthermore, the AOG contains no stabilizer molecules and can be highly pure, which is very favorable for its applications.We found that the AOG aqueous dispersion was rather stable. Eve...

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Flexible Graphene Films via the Filtration of Water-Soluble Noncovalent Functionalized Graphene Sheets

Cited by 3,109 publications

References 23 publications

Nanotomy-based production of transferable and dispersible graphene nanostructures of controlled shape and size

Nanotomy-based production of transferable and dispersible graphene nanostructures of controlled shape and size

Self-assembled two-dimensional nanofluidic proton channels with high thermal stability

Mildly Oxidized Graphene: Facile Synthesis, Characterization, and Application as a Matrix in MALDI Mass Spectrometry

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