A topological twist on materials science

Gupta, Sanju; Saxena, Avadh

doi:10.1557/mrs.2014.28

Cited by 50 publications

(22 citation statements)

References 99 publications

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“…1 This incipient appreciation for the importance of topology is giving rise in the last years to entirely new materials with unusual topologies that lead to either exotic or enhanced properties. [2][3][4] Selfassembly of small molecules has received great attention in this field in the past decade, not only because of their fascinating and innumerable supramolecular morphologies (including spherical or cylindrical micelles, vesicles, toroids, rods, ribbons, lamellar platelets, scrolls or nanotubes) 5 but also due to their potential applications in material science, 6 mimic biological systems or functions 7,8 or in molecular devices.…”

Section: Introductionmentioning

confidence: 99%

Tuning supramolecular aurophilic structures: the effect of counterion, positive charge and solvent

et al. 2016

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The synthesis of the cationic gold(I) complexes [Au (C≡CC 5 These results reveal the importance of the introduction of a positive charge on the global supramolecular assemblies and how the counterion can modify also the resulting package. Interestingly, we have also proved that the aggregation of complexes 2, 3, 5and 6 is also affected by the solvent with direct influence on their absorption and emission properties and the global morphology of the aggregates.

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Section: Introductionmentioning

confidence: 99%

Tuning supramolecular aurophilic structures: the effect of counterion, positive charge and solvent

et al. 2016

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“…Both theoretically and experimentally described the D band as being ‘locally activated’, i.e. it only becomes active in the near vicinity of an imperfection (such as edge or a point or topological defects namely, the Pentagon–Heptagon (P–H) or Stone–Wales defect (S–W) and/or the ‘mitosis’ defect) . Therefore, one can associate a characteristic length scale as typical decay distance of the D band intensity.…”

Section: Resultsmentioning

confidence: 99%

Multiphonon Raman spectroscopy properties and Raman mapping of 2D van der Waals solids: graphene and beyond

Gupta

Heintzman

Jasiński

2015

J Raman Spectroscopy

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Strong in-plane bonding (covalent) and weak van der Waals (vdW) interplanar interactions characterize a number of layered solids, as epitomized by graphite. The advent of graphene (Gr), individual atomic two-dimensional (2D) layers, isolated from mineral graphite via micromechanical exfoliation enabled the ability to pick, place and stack of arbitrary compositions. Moreover, this discovery implicated an access to other 2D vdW solids beyond graphene and artificially stacking atomic layers forming heterostructures/superlattices. Raman spectroscopy (RS) is a fast reliable non-destructive analytical tool and an integral part for lattice dynamical structural characterization of crystalline solids at nanoscale, revealing not only the collective atomic/molecular motions but also localized vibrations/modes and specifically used to determine the number of graphene layers and of other 2D vdW solids. We present Raman spectroscopy in first-, second-and higher-order vibrational modes involving 3 and 4 phonons (overtones and combination) and mapping of graphene (mono-, bi-, tri-and few-) layers, semiconducting transition metal dichalcogenides (TMDs) [molybdenum disulfide (MoS 2 ) and tungsten disulfide (WS 2 )] and wide bandgap hexagonal boron nitride (h-BN) dispersed monolayers, revealing various molecular vibrations and structural quality/disorder. First-and higherorder phonon modes are observed and analyzed in terms of Raman intensity (spatial inhomogeneity or thickness variation), band position (intrinsic mechanical strain) and intensity ratio (structural disorder) as a function of graphene layer (n). An empirical relation for G band position with n is corroborated. All of the higher order modes are observed to upshift almost linearly with n, betraying the underlying interlayer vdW interactions. These findings exemplify the evolution of structural parameters in layered materials in changing from 3-to 2-or low-dimensional regime. The results are presented in view of applications of graphene by itself and in combination that help better understanding of physical and electronic properties for nano-/optoelectronics.

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“…Likewise, curvatures can provide insight into the operating thermodynamics that operates in the geometry of a microstructure through H and K 25 . The 3D mesh supplies also information about global topology, a field of geometry of increasing interest in materials science 26 , 27 . Topology studies invariance of certain properties under smooth continuous mechanical deformation and it is characterised by an integer parameter called genus, g .…”

Section: Discussionmentioning

confidence: 99%

Three-dimensional chemical mapping using non-destructive SEM and photogrammetry

Gontard¹,

Batista

Salguero

et al. 2018

Sci Rep

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The slice and view approach in electron microscopy defines an ensemble of destructive techniques that is widely used for studying in 3D the structure and chemistry of samples with dimensions ranging from µm to mm. Here, a method is presented for measuring with high resolution and quantitatively the morphology and chemical composition of the surface of a sample in 3D. It is non-destructive and therefore, it is complementary to slice and view methods. The scheme is based on the fusion of conventional scanning electron microscopy (SEM) imaging, multi-view photogrammetry and compositional mapping using energy dispersive X-ray spectroscopy (EDXS). We demonstrate its potential by performing an accurate study of adhesion wear of a tungsten carbide tool that is difficult to obtain using conventional characterization techniques.

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A topological twist on materials science

Abstract: Abstract

Cited by 50 publications

References 99 publications

Tuning supramolecular aurophilic structures: the effect of counterion, positive charge and solvent

Tuning supramolecular aurophilic structures: the effect of counterion, positive charge and solvent

Multiphonon Raman spectroscopy properties and Raman mapping of 2D van der Waals solids: graphene and beyond

Three-dimensional chemical mapping using non-destructive SEM and photogrammetry

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