Multiscale, Hierarchical Patterning of Graphene by Conformal Wrinkling

Lee, Won Kyu; Kang, Junmo; Chen, Kan Sheng; Engel, Clifford J.; Jung, Woo‐Bin; Rhee, Dongjoon; Hersam, Mark C.; Odom, Teri W.

doi:10.1021/acs.nanolett.6b03415

Cited by 96 publications

(103 citation statements)

References 27 publications

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“…Nanoindentation tests showed that fracture loads at the grain boundaries are 20 to 40% smaller than in pristine graphene, representing at most a 15% reduction of the intrinsic strength (Figure 5e,f) [108]. Lee et al used hierarchical patterning to obtain conformal wrinkling with a soft skin layer [121]. The wrinkle wavelength could be finely controlled by tuning the skin layer's thickness.…”

Section: Dmentioning

confidence: 99%

“…The conductivity of graphene, however, could be preserved even under structural deformation. C-AFM measurements on wrinkled graphene showed that the current at a fixed bias was similar across the boundaries between crumples and wrinkle domains with different wavelengths, despite the presence of such defective structures having shown a clear effect on stiffness and adhesion [121]. The effect of mechanical strain on the electrical conductivity of suspended MoS 2 membranes was probed by positioning the AFM tip in the center of a flake connected to two microfabricated electrodes.…”

Section: Strain Engineering and Piezoresponse Force Microscopymentioning

confidence: 99%

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Advanced Scanning Probe Microscopy of Graphene and Other 2D Materials

Musumeci

2017

Crystals

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Two-dimensional (2D) materials, such as graphene and metal dichalcogenides, are an emerging class of materials, which hold the promise to enable next-generation electronics. Features such as average flake size, shape, concentration, and density of defects are among the most significant properties affecting these materials' functions. Because of the nanoscopic nature of these features, a tool performing morphological and functional characterization on this scale is required. Scanning Probe Microscopy (SPM) techniques offer the possibility to correlate morphology and structure with other significant properties, such as opto-electronic and mechanical properties, in a multilevel characterization at atomic-and nanoscale. This review gives an overview of the different SPM techniques used for the characterization of 2D materials. A basic introduction of the working principles of these methods is provided along with some of the most significant examples reported in the literature. Particular attention is given to those techniques where the scanning probe is not used as a simple imaging tool, but rather as a force sensor with very high sensitivity and resolution.

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Section: Dmentioning

confidence: 99%

Section: Strain Engineering and Piezoresponse Force Microscopymentioning

confidence: 99%

Advanced Scanning Probe Microscopy of Graphene and Other 2D Materials

Musumeci

2017

Crystals

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“…The idea consists of designing structural components that themselves are structured at multiple levels, through the introduction of features at multiple length scales. Notable consequences of multiscale design include simultaneous enhancement of strength and toughness, counterintuitive behavior such as negative Poisson's ratios, biological examples of integrating multiple functions such as antireflection, superhydrophobicity, and antifogging in the eyes of insects, tuning mechanical behavior of layered materials by hierarchical structuring while retaining macroscale electrical conductivity, and several others. Few studies have demonstrated that a hierarchical pattern is superior to a single‐level pattern in terms of superhydrophobicity and light trapping for enhanced absorption in solar cells .…”

Section: Introductionmentioning

confidence: 99%

Shaping Resonant Light Confinement and Optoelectronic Spectra Using Strain in Hierarchical Multiscale Structures

Jagdish

Panidhara

Satyanarayana

et al. 2019

Advanced Optical Materials

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Hierarchically structured optical materials have been a topic of intriguing research interest due to the possibility of tailoring material properties beyond the limits of bulk continuum material design. Here, an optical confinement phenomenon in a hierarchically structured waveguide platform consisting of alternating clusters of nanostructured and planar microscale domains is demonstrated. An unconventional self‐assembly‐based strain‐assisted nanomolding process is developed to fabricate these hierarchically structured multiperiodic waveguides. Further, these hierarchically patterned waveguides are used as substrates for solution‐processed photodetectors. The optical confinement occurring due to the nanoscale scattering and the wavelength‐dependent interaction between the planar and structured microdomains leads to an improved uniformity in the optoelectronic spectral response of these photodetectors. Furthermore, by tuning the multiperiodicity within the nanostructured domain structure, using a mechanical strain of 20%, an improvement of around 10% in the uniformity of the optoelectronic spectral response of the photodetectors is demonstrated. Simulations further show that these processes arise only in the presence of a hierarchical structure, due to multiscale interaction, through wavelength‐selective coupling of scattered light from nanostructured domains to the planar microdomains. In summary, hierarchical structures can address optoelectronic problems that cannot be addressed by simpler structures.

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“…graphene and MoS2), 23-28 and the morphology can be controlled using lithography. 24,25,29,30 Previous studies with wrinkled catalysts show improvement in different electrochemical reactions including hydrogen evolution reaction (HER), 25,27,28,30 glucose sensing, 31 and DNA detection. 32 For example, wrinkled platinum (Pt) arrays electrodes improved the performance of HER from ~70 mA/cm 2 to ~ 120 mA/cm 2 at 0.1 V as compared to conventional Pt on carbon.…”

mentioning

confidence: 99%

Nano-Folded Gold Electrocatalysts Enhance the Selectivity of Carbon Dioxide Reduction

Kwok¹,

Wang²,

Cao³

et al. 2019

Preprint

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The local structure and geometry of catalytic interfaces can influence the selectivity of chemical reactions. Here, using a pre-strained polymer, we uniaxially compress a thin gold film to form a nano-folded catalyst. We observe two kinds of folds and can tune the ratio of loose to tight folds by varying the extent of pre-strain in the polymer. We characterize the nano-folded catalysts using x-ray diffraction, scanning, and transmission electron microscopy. We observe grain reorientation and coarsening in the nano-folded gold catalysts. Electroreduction of carbon dioxide with these nano-folded catalysts reveals an enhancement of Faradaic efficiency for carbon monoxide formation by a factor of about four. This result suggests that electrolyte mass transport limitations and an increase of the local pH in the tight folds of the catalyst outweigh the effects of alterations in grain characteristics. Together, our studies demonstrate that nano-folded geometries can significantly alter grain characteristics, mass transport, and catalytic selectivity.Electroreduction of carbon dioxide (CO2) to valuable carbon-rich products is a potential solution to end the anthropogenic carbon cycle. 1,2 However, slow kinetics and reduced control over product yield and selectivity have hindered widespread commercial viability. 3,4 Nanostructured catalysts offer the potential to address these limitations. 5 Indeed, a variety of nanoparticles, 6-9 thin films, 10-14 and nanoporous materials 15-18 have been explored, but there are still challenges with scalability, reproducibility, extreme reaction conditions, and cost. 6,10,12,15 Mechanical wrinkling of metallic thin films using pre-strained polystyrene (PS) substrates offers a reproducible strategy to create nanostructured interfaces. This approach is compatible with nanoparticles, 19 nanoporous, 20 thin films, 21,22 and twodimensional (2D) materials (e.g. graphene and MoS2), 23-28 and the morphology can be controlled using lithography. 24,25,29,30 Previous studies with wrinkled catalysts show improvement in different electrochemical reactions including hydrogen evolution reaction (HER), 25,27,28,30 glucose sensing, 31 and DNA detection. 32 For example, wrinkled platinum (Pt) arrays electrodes improved the performance of HER from ~70 mA/cm 2 to ~ 120 mA/cm 2 at 0.1 V as compared to conventional Pt on carbon. This improvement was attributed to weak adhesion of hydrogen (H2) gas bubbles, resulting in a lower overpotential.Here, for the first time, we present evidence that a nano-folded gold (Au) catalyst can improve the selectivity of CO2 reduction. We utilized a pre-strained PS substrate to uniaxially compress and create a novel Au catalyst with a combination of loose (>200

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Multiscale, Hierarchical Patterning of Graphene by Conformal Wrinkling

Cited by 96 publications

References 27 publications

Advanced Scanning Probe Microscopy of Graphene and Other 2D Materials

Advanced Scanning Probe Microscopy of Graphene and Other 2D Materials

Shaping Resonant Light Confinement and Optoelectronic Spectra Using Strain in Hierarchical Multiscale Structures

Nano-Folded Gold Electrocatalysts Enhance the Selectivity of Carbon Dioxide Reduction

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