Graphene, the new nanocarbon

Rao, C. N. R.; Biswas, Kanishka; Subrahmanyam, K. S.; Govindaraj, A.

doi:10.1039/b815239j

Cited by 738 publications

(377 citation statements)

References 57 publications

Supporting

Mentioning

346

Contrasting

Unclassified

Order By: Relevance

“…Thus, an important use of nanomaterials is in reinforcing polymer matrices taking advantage of the ultra-high stiffness and hardness exhibited by them. Recent research has shown that small additions (up to Ϸ1 wt%) of certain nanomaterials such as carbon nanaotubes enhance the mechanical properties markedly, sometimes by as much as 100% (1)(2)(3)(4)(5)(6)(7)(8). Although the precise mechanism responsible for this dramatic enhancement is not entirely understood, it is generally believed that molecular level interactions between the nanomaterials and polymer matrices play a major role.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Extraordinary synergy in the mechanical properties of polymer matrix composites reinforced with 2 nanocarbons

Prasad

Das²,

Maitra³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

276

190

View full text Add to dashboard Cite

One of the applications of nanomaterials is as reinforcements in composites, wherein small additions of nanomaterials lead to large enhancements in mechanical properties. There have been extensive studies in the literature on composites where a polymer matrix is reinforced by a single nanomaterial such as carbon nanotubes. In this article, we examine the significant synergistic effects observed when 2 different types of nanocarbons are incorporated in a polymer matrix. Thus, binary combinations of nanodiamond, fewlayer graphene, and single-walled nanotubes have been used to reinforce polyvinyl alcohol. The mechanical properties of the resulting composites, evaluated by the nanoindentation technique, show extraordinary synergy, improving the stiffness and hardness by as much as 400% compared to those obtained with single nanocarbon reinforcements. These results suggest a way of designing advanced materials with extraordinary mechanical properties by incorporating small amounts of 2 nanomaterials such as graphene plus nanodiamond or nanodiamond plus carbon nanotube.binary combinations ͉ nanoindentation technique ͉ polyvinyl alcohol ͉ synergistic effects A mong the many unique attributes of nanomaterials, especially noteworthy are their large surface to volume ratios and outstanding mechanical properties. These properties offer venues for exciting areas of research as well as for technological innovations. Thus, an important use of nanomaterials is in reinforcing polymer matrices taking advantage of the ultra-high stiffness and hardness exhibited by them. Recent research has shown that small additions (up to Ϸ1 wt%) of certain nanomaterials such as carbon nanaotubes enhance the mechanical properties markedly, sometimes by as much as 100% (1-8). Although the precise mechanism responsible for this dramatic enhancement is not entirely understood, it is generally believed that molecular level interactions between the nanomaterials and polymer matrices play a major role. The large interface area available for such interactions clearly hold the key for the dramatic enhancement in mechanical properties.Of the variety of nanomaterials synthesized and characterized in recent years, nanocarbons of different dimentionalities are of particular interest, as exemplified by nanodiamond, nanotubes and graphene with dimensionalities of 0, 1, and 2, respectively (1-3). Extensive research has been carried out on the mechanical properties of composites made of polymer matrices with 1 of the nanocarbons as the reinforcement phase (1-8). We would expect the nature of interaction of the nanocarbon constituent with the matrix to vary with the dimensionality. For example, carbon nanotubes added to a polymer can interact over the length of the polymer chain whereas a nanodiamond particle can interact only at a point, possibly at the ends of a polymer chain. While each of the nanocarbons improves the mechanical properties of the polymer matrix, we felt intuitively that incorporation of 2 nanocarbons could lead to synergistic effects in the m...

show abstract

mentioning

confidence: 99%

“…Extensive research has been carried out on the mechanical properties of composites made of polymer matrices with 1 of the nanocarbons as the reinforcement phase (1)(2)(3)(4)(5)(6)(7)(8). We would expect the nature of interaction of the nanocarbon constituent with the matrix to vary with the dimensionality.…”

mentioning

confidence: 99%

Extraordinary synergy in the mechanical properties of polymer matrix composites reinforced with 2 nanocarbons

Prasad

Das²,

Maitra³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

276

190

View full text Add to dashboard Cite

show abstract

“…From the Z-scan experiments at intensity ~16 GW/cm 2 we observe a saturable absorption behavior. The graphene samples studied by us show positive change in the differential transmission of the probe in the pump-probe experiment along with two component relaxation dynamics in the range of 130-330 fs and 3.5-4.9 ps associated with the carrier-carrier and carrier-phonon scattering processes in graphene.Solution-phase and chemical exfoliation techniques provide a low-cost, high-yield method for mass production of graphene [8][9][10][11][12][13][14] as compared to commonly used methods such as micromechanical cleavage and epitaxial growth. For our study, graphene suspensions were prepared in three different solvents, distilled water, dimethylformamide (DMF) and tetrahydrofuran (THF).…”

mentioning

confidence: 99%

“…Solution-phase and chemical exfoliation techniques provide a low-cost, high-yield method for mass production of graphene [8][9][10][11][12][13][14] as compared to commonly used methods such as micromechanical cleavage and epitaxial growth. For our study, graphene suspensions were prepared in three different solvents, distilled water, dimethylformamide (DMF) and tetrahydrofuran (THF).…”

mentioning

confidence: 99%

Femtosecond carrier dynamics and saturable absorption in graphene suspensions

Kumar

Anija

Kamaraju

et al. 2009

Applied Physics Letters

Self Cite

210

147

View full text Add to dashboard Cite

Nonlinear optical properties and carrier relaxation dynamics in graphene, suspended in three different solvents, are investigated using femtosecond (80 fs pulses) Z-scan and degenerate pumpprobe spectroscopy at 790 nm. The results demonstrate saturable absorption property of graphene with a nonlinear absorption coefficient, β, of ~2 to 9x10 -8 cm/W. Two distinct time scales associated with the relaxation of photoexcited carriers, a fast one in the range of 130-330 fs (related to carriercarrier scattering) followed by a slower one in 3.5-4.9 ps range (associated with carrier-phonon scattering) are observed.Graphene is a two-dimensional carbon nanomaterial which has received tremendous interest in recent years owing to its various remarkable properties and applications in modern electronics and photonics [1,2]. Ultrafast degenerate and nondegenerate pump-probe measurements on single and multilayer epitaxial [3,4] or exfoliated [5] graphenes deposited on a substrate have shown two types of dynamics of the carriers: a fast component of the order of ~100 fs attributed to the intraband carrier-carrier scattering and a slower component ~2 ps associated with carrierphonon scattering. In the degenerate pump-probe studies on single and multilayer graphene films grown on a SiC substrate using 85 fs laser pulses centered at 790 nm, a positive change in the transient differential transmission of the probe was observed with two relaxation times, the faster one in the range of 70-120 fs and a slower one between 0.4-1.7 ps [3]. Similar carrier relaxation dynamics was obtained in the nondegenerate pump-probe experiments on exfoliated graphene films on SiO 2 /Si substrate [5]. On a few layer thick graphene film on SiC, nondegenerate pump-probe experiments [4] using 800 nm pump showed that the sign of the differential transmission signal is positive over the entire probe spectral range of 1.1 to 2.6 µm but becomes negative after 2 ps if the probe wavelength falls between 1.78 and 2.35 µm. The initial positive part of the signal within 150 fs has been described in terms of thermalization and emission of high energy-phonons followed by a slow decay of the order of a few ps determined by electron-acoustic phonon scattering. Nonlinear optical properties of graphene have been reported recently in the nanosecond (ns) and picosecond (ps) regimes [6,7]. Using 35 ps laser pulses centered at 532 nm, it has been shown that the nonlinear response of graphene oxide suspensions changes from saturable absorption at low intensity (2.1 GW/cm 2 ) to reverse saturable absorption or optical limiting at higher intensities (>4.5 GW/cm 2 ) [6]. In comparison, in the ns regime suspensions of graphene oxide and functionalized graphene in dimethylformamide showed optical limiting property at all values of intensities above 0.6 GW/cm 2 [6,7].We have carried out femtosecond (80 fs) Z-scan and degenerate pump-probe experiments at 790 nm to study the nonlinear optical response and carrier dynamics in colloidal suspensions of graphene which have not been invest...

show abstract

“…The fact that its precursor (graphite) is readily available makes it all the more tempting [9]. Defectfree graphene presents outstanding physical properties, such as high intrinsic mobility and ballistic transport, high thermal conductivity and Young's modulus, an optical transmittance of almost 98 % and a large specific surface area [1,10,11]. Much attention has been given to the characterization of graphene and its derivatives so we will not be discussing the properties of graphene.…”

Section: Introductionmentioning

confidence: 99%

Graphene synthesis: a Review

Shams

Zhang

Zhu

2015

Materials Science-Poland

135

View full text Add to dashboard Cite

Graphene has achieved a great amount of popularity and interest from the science world because of its extraordinary physical, mechanical and thermal properties. Graphene is an allotrope of carbon, having one-atom-thick planar sheets of sp 2 bonded carbon atoms densely packed in a honeycomb crystal lattice. Many methods to synthesize graphene have been developed over a short period and we believe it is necessary to create a list of the most notable approaches. This article focuses on the methods to synthesize graphene in an attempt to summarize and document advancements in the synthesis of graphene research and future prospects.

show abstract

Graphene, the new nanocarbon

Cited by 738 publications

References 57 publications

Extraordinary synergy in the mechanical properties of polymer matrix composites reinforced with 2 nanocarbons

Extraordinary synergy in the mechanical properties of polymer matrix composites reinforced with 2 nanocarbons

Femtosecond carrier dynamics and saturable absorption in graphene suspensions

Graphene synthesis: a Review

Contact Info

Product

Resources

About