Symmetry Breaking of Graphene Monolayers by Molecular Decoration

Dong, Xiaochen; Shi, Yumeng; Zhao, Yue; Chen, Dongmeng; Ye, Jun; Yao, Yanjuan; Gao, Fang; Ni, Zhenhua; Yu, Ting; Shen, Zexiang; Huang, Yongmei; Chen, Peng; Li, Lain‐Jong

doi:10.1103/physrevlett.102.135501

Cited by 234 publications

(150 citation statements)

References 20 publications

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“…Simultaneous presence of the nano and micro fibers is one of the novel properties of the synthesized PVDF/G films that promotes the film properties in some aspects of porosity, hydrophobicity, etc. [33][34][35][36][37].…”

Section: Morphology and Crystallographic Studiesmentioning

confidence: 99%

Preparation and Characterization of Polyvinylidene Fluoride/Graphene Superhydrophobic Fibrous Films

Karimi-Sabet²,

et al. 2015

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Abstract:A new strategy to induce superhydrophobicity via introducing hierarchical structure into the polyvinylidene fluoride (PVDF) film was explored in this study. For this purpose nanofibrous composite films were prepared by electrospinning of PVDF and PVDF/graphene blend solution as the main precursors to produce a net-like structure. Various spectroscopy and microscopy methods in combination with crystallographic and wettability tests were used to evaluate the characteristics of the synthesized films. Mechanical properties have been studied using a universal stress-strain test. The results show that the properties of the PVDF nanofibrous film are improved by compositing with graphene. The incorporation of graphene flakes into the fibrous polymer matrix changes the morphology, enhances the surface roughness, and improves the hydrophobicity by inducing a morphological hierarchy. Superhydrophobicity with the water contact angle of about 160° can be achieved for the PVDF/graphene electrospun nanocomposite film in comparison to PVDF pristine film.

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Section: Morphology and Crystallographic Studiesmentioning

confidence: 99%

Preparation and Characterization of Polyvinylidene Fluoride/Graphene Superhydrophobic Fibrous Films

Karimi-Sabet²,

et al. 2015

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“…For example, non-covalent molecular functionalization has been used to dope single layer graphene and to induce band-gap in bilayer graphene [32,33], for surface transfer doping of diamond (100) with tetrafluorotetracyanoquinodimethane [34], for reduction of sheet resistance in organic photovoltaic cells (OPVs) [35], to improve the selectivity and sensitivity of molecular biosensors [36,37] and for electrochemical storage applications [38,39]. Therefore, a step towards developing high performance electrode material for electrochemical capacitors based on functionalized graphene sheet is highly desirable.…”

Section: Introductionmentioning

confidence: 99%

Functionalized graphene foam as electrode for improved electrochemical storage

Bello

Fabiane

Momodu

et al. 2014

J Solid State Electrochem

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We report on a non-covalent functionalization of graphene foam (GF) synthesised via chemical vapor deposition (CVD). The GF was treated with pyrene carboxylic acid (PCA) which acted as a source of oxygen and/ or hydroxyl groups attached to the surface of the graphene foam for its electrochemical performance improvement.The modified graphene surface enabled a high pseudocapacitive effect on the GF. A specific capacitance of 133.3 F g -1 , power density ∼145.3 kW kg -1 , and energy density ∼4.7 W h kg -1 was achieved based on the functionalized foam in 6 M KOH aqueous electrolyte. The results suggest that non-covalent functionalization might be an effective approach to overcome the restacking problem associated with graphene electrodes and also signifies the importance of surface functionalities in graphene based electrode materials.

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“…1 Graphene's unique electronic, chemical, and mechanical properties and its potential applications have been extensively studied. Chemically modified graphene has been investigated, 2 and hydrogen (H)-terminated graphene, known as graphane, has also been found to be theoretically stable. 3 Further theoretical studies have examined its structural, magnetic, and optical properties, [4][5][6][7][8][9] and its experimental synthesis has also been investigated.…”

mentioning

confidence: 99%

Laser-induced preferential dehydrogenation of graphane

2012

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We have used first-principles simulations based on time-dependent density functional theory to show that short laser pulses can trigger preferential hydrogen desorption from the upper or lower side of suspended graphane (H-terminated graphene). This control is achieved by using intense ultrashort p-polarized laser pulses (∼2 fs) with an asymmetric time envelope. The dynamical Stark effect induced by the pulse creates an asymmetric charge distribution and force field on the H ions, even at low laser fluence. At finite temperatures the carbon-hydrogen stretching softens, favoring H desorption from one side. This transient geometry can be modified by halogen functionalization, which results in a two-dimensional dipolar structure. Single-layer graphene is fabricated by mechanically peeling off a layer of carbon from pyrolytic graphite.1 Graphene's unique electronic, chemical, and mechanical properties and its potential applications have been extensively studied. Chemically modified graphene has been investigated, 2 and hydrogen (H)-terminated graphene, known as graphane, has also been found to be theoretically stable.3 Further theoretical studies have examined its structural, magnetic, and optical properties, 4-9 and its experimental synthesis has also been investigated. 10,11 Graphene that is H terminated on only one side has also been proposed for use in spin-polarized devices with the structure known as graphone, 12 or as a gapped semiconductor material with full H coverage. 13In this Rapid Communication we propose a way of H desorption, which is mainly from one side of a suspended graphane sheet, with the use of an asymmetric pulse of the femtosecond laser by performing first-principles simulations. Further chemical modification of this side with other reactive species can reach the heterogeneously terminated graphene, which was recently studied.14 We emphasize that this asymmetrically biased desorption is thermodynamically difficult and thus has not been considered in former theoretical studies for stability, 15,16 because the carbon-hydrogen (C-H) bond is the same on both sides. The femtosecond laser pulse has an asymmetric electric field (E-field) time envelope in order to induce dehydrogenation on one side of the graphane in our first-principles molecular dynamics calculations, based on the Ehrenfest time-dependent density functional theory (E-TDDFT) framework. 17,18 In this work, the z axis is set normal to the graphane sheet with the sheet at z = 0, and z > 0 and z < 0 are taken as the upper and lower regions, respectively (Fig. 1). An E-field polarized normal to the graphane sheet with the envelope shown in Fig. 2 results in a positive (upward) force on the ions and a negative force on the electrons. The H atoms in the upper region are desorbed from the sheet by this pulse, whereas the H atoms in the lower region remain bound. Thus, the upper graphene region remains chemically active, making this graphone sheet transient, which can be used for further functionalization. 19 We provide a complete microscopi...

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Symmetry Breaking of Graphene Monolayers by Molecular Decoration

Cited by 234 publications

References 20 publications

Preparation and Characterization of Polyvinylidene Fluoride/Graphene Superhydrophobic Fibrous Films

Preparation and Characterization of Polyvinylidene Fluoride/Graphene Superhydrophobic Fibrous Films

Functionalized graphene foam as electrode for improved electrochemical storage

Laser-induced preferential dehydrogenation of graphane

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