Solution Phase Production of Graphene with Controlled Thickness via Density Differentiation

Green, Alexander A.; Hersam, Mark C.

doi:10.1021/nl902200b

Cited by 720 publications

(688 citation statements)

References 38 publications

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“…Simulation studies confirmed that planar SC molecules partially cover 60% of the graphene surface and are adsorbed parallel to the graphene surface to maximize the hydrophobic interactions [104,105]. However, the computed adsorption still falls short of the value reported by Green et al [106] estimating that 94% of the graphene surface is occupied and SDBS), the resulting dispersion did not consist entirely of single layer graphene, but a co-existing distribution with multilayer graphene (MLG). A study on graphene dispersion using SC was also reported by Tkalya et al [28].…”

Section: Accepted M Manuscriptmentioning

confidence: 83%

Graphene-philic surfactants for nanocomposites in latex technology

Mohamed

Ardyani

Bakar

et al. 2016

Advances in Colloid and Interface Science

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Graphene is the newest member of the carbon family, and has revolutionized materials science especially in the field of polymer nanocomposites. However, agglomeration and uniform dispersion remains an Achilles" heel (even an elephant in the room), hampering the optimization of this material for practical applications. Chemical functionalization of graphene can overcome these hurdles but is often rather disruptive to the extended piconjugation, altering the desired physical and electronic properties. Employing surfactants as stabilizing agents in latex technology circumvents the need for chemical modification allowing for the formation of nanocomposites with retained graphene properties. This article reviews the recent progress in the use of surfactants and polymers to prepare graphene/polymer nanocomposites via latex technology. Of special interest here are surfactant structure-performance relationships, as well as background on the roles surfactantgraphene interactions for promoting stabilization.

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Section: Accepted M Manuscriptmentioning

confidence: 83%

Graphene-philic surfactants for nanocomposites in latex technology

Mohamed

Ardyani

Bakar

et al. 2016

Advances in Colloid and Interface Science

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“…Based on the resulting FWHM of 2D band for our graphene (86 cm -1 ), and reported FWHM of 2D band for monolayer graphene (35 cm -1 ) (Green and Hersam 2009), the produced value of hNi for G GA seems to imply that majority of G GA sheets are bilayer when only FWHM of 2D band was concerned. However, this resulting value is not accurate enough as the proposed metric is only suitable for thickness measurement of single graphene sheet (Green and Hersam 2009) and not for vacuum-filtered graphene film. Moreover, our produced graphene is not as pristine as the metric required due to its functionalisation with gum Arabic.…”

Section: Characterisations Of Graphenementioning

confidence: 92%

“…The mean layer number hNi of G GA meanwhile was evaluated from the Raman data through intensity ratio measurement of full-width half maximum (FWHM) for 2D band (Green and Hersam 2009). Based on the resulting FWHM of 2D band for our graphene (86 cm -1 ), and reported FWHM of 2D band for monolayer graphene (35 cm -1 ) (Green and Hersam 2009), the produced value of hNi for G GA seems to imply that majority of G GA sheets are bilayer when only FWHM of 2D band was concerned.…”

Section: Characterisations Of Graphenementioning

confidence: 99%

Application of graphene from exfoliation in kitchen mixer allows mechanical reinforcement of PVA/graphene film

et al. 2017

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Mechanical properties of polyvinyl alcohol (PVA) can be reinforced from the addition of graphene into its matrix. However, pristine graphene lacks solubility in water and thus makes dispersion a challenging task. Notably, functionalisation of graphene is required to accommodate graphene presence in the water. In this work, we have used a kitchen mixer to produce gum Arabicgraphene (G GA ) for the first time as filler for mechanical reinforcement of PVA. For the characterisation of exfoliated graphene, mean lateral size of G GA was measured from the imaging by transmission electron microscopy while the mean thickness of graphene was predicted from the obtained spectra by Raman spectroscopy. During the preparation of PVA/graphene film by solution casting, G GA was varied between 0, 0.05, 0.075, 0.10 and 0.15 wt% in concentration. We found that the presence of G GA in PVA improves the tensile stress and elastic modulus about 72-200 and 19-187% from the original values. The data from Halpin-Tsai meanwhile suggested that the mechanical reinforcement of PVA/graphene film is due to the random distribution network of G GA in PVA.

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“…Rational control over nanosheet thickness and size is likely to be required for nanoelectronics and in particular optoelectronics. Also by analogy with graphene, new layer-controlled chemistries 63 and post-synthesis sorting of flakes by layer thickness 64 and lateral size 65 may offer solutions.…”

mentioning

confidence: 99%

Electronics and optoelectronics of two-dimensional transition metal dichalcogenides

et al. 2012

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699M any two-dimensional (2D) materials exist in bulk form as stacks of strongly bonded layers with weak interlayer attraction, allowing exfoliation into individual, atomically thin layers 1 . The form receiving the most attention today is graphene, the monolayer counterpart of graphite. The electronic band structure of graphene has a linear dispersion near the K point, and charge carriers can be described as massless Dirac fermions, providing scientists with an abundance of new physics 2,3 . Graphene is a unique example of an extremely thin electrical and thermal conductor 4 , with high carrier mobility 5 , and surprising molecular barrier properties 6,7 .Many other 2D materials are known, such as the TMDCs 8,9 , transition metal oxides including titania-and perovskite-based oxides 10,11 , and graphene analogues such as boron nitride (BN) 12,13 . In particular, TMDCs show a wide range of electronic, optical, mechanical, chemical and thermal properties that have been studied by researchers for decades 9,14,15 . There is at present a resurgence of scientific and engineering interest in TMDCs in their atomically thin 2D forms because of recent advances in sample preparation, optical detection, transfer and manipulation of 2D materials, and physical understanding of 2D materials learned from graphene.The 2D exfoliated versions of TMDCs offer properties that are complementary to yet distinct from those in graphene. Graphene displays an exceptionally high carrier mobility exceeding 10 6 cm 2 V -1 s -1 at 2 K (ref. 16) and exceeding 10 5 cm 2 V -1 s -1 at room temperature for devices encapsulated in BN dielectric layers 5 ; because pristine graphene lacks a bandgap, however, fieldeffect transistors (FETs) made from graphene cannot be effectively switched off and have low on/off switching ratios. Bandgaps can be engineered in graphene using nanostructuring [17][18][19] , chemical functionalization 20 and applying a high electric field to bilayer graphene 21 , but these methods add complexity and diminish mobility. In contrast, several 2D TMDCs possess sizable bandgaps around 1-2 eV (refs 9,14), promising interesting new FET and optoelectronic devices.TMDCs are a class of materials with the formula MX 2 , where M is a transition metal element from group IV (Ti, Zr, Hf and so on), group V (for instance V, Nb or Ta) or group VI (Mo, W and so on), and X is a chalcogen (S, Se or Te). These materials form layered structures of the form X-M-X, with the chalcogen atoms in two hexagonal planes separated by a plane of metal atoms, as shown in Fig. 1a. Adjacent layers are weakly held together to form the bulk crystal in a variety of polytypes, which vary in stacking orders and metal atom coordination, as shown in Fig. 1e. The overall symmetry of TMDCs is hexagonal or rhombohedral, and the metal atoms have octahedral or trigonal prismatic coordination. The electronic properties of TMDCs range from metallic to semiconducting, as summarized in Table 1. There are also TMDCs that exhibit exotic behaviours such as charge density waves ...

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Solution Phase Production of Graphene with Controlled Thickness via Density Differentiation

Cited by 720 publications

References 38 publications

Graphene-philic surfactants for nanocomposites in latex technology

Graphene-philic surfactants for nanocomposites in latex technology

Application of graphene from exfoliation in kitchen mixer allows mechanical reinforcement of PVA/graphene film

Electronics and optoelectronics of two-dimensional transition metal dichalcogenides

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