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Journal ArticleDOI

Raman spectrum of graphene and graphene layers.

TL;DR: This work shows that graphene's electronic structure is captured in its Raman spectrum that clearly evolves with the number of layers, and allows unambiguous, high-throughput, nondestructive identification of graphene layers, which is critically lacking in this emerging research area.
Abstract: Graphene is the two-dimensional building block for carbon allotropes of every other dimensionality We show that its electronic structure is captured in its Raman spectrum that clearly evolves with the number of layers The D peak second order changes in shape, width, and position for an increasing number of layers, reflecting the change in the electron bands via a double resonant Raman process The G peak slightly down-shifts This allows unambiguous, high-throughput, nondestructive identification of graphene layers, which is critically lacking in this emerging research area

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Journal ArticleDOI
01 Mar 2014-Carbon
TL;DR: A series of nitrogen-doped porous carbons are prepared through KOH activation of a nonporous nitrogen-enriched carbon which is synthesized by pyrolysis of the polymerized ethylenediamine and carbon tetrachloride as discussed by the authors.

332 citations


Cites background from "Raman spectrum of graphene and grap..."

  • ...[37] Ferrari AC, Meyer JC, Scardaci V, Casiraghi C, Lazzeri M, Mauri F, et al....

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  • ...The peaks at 1350 and 1596 cm 1 are represented as the D band and the G band, respectively, which are characteristic Raman peaks for carbon materials [37,38]....

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Journal ArticleDOI
TL;DR: In this article, the significant impact of 2D GNSs on the volume change of Sn-based anodes during cycling is discussed, along with their preparation methods, properties and enhanced LIB performance.

331 citations

DOI
Claudia Backes1, Claudia Backes2, Amr M. Abdelkader3, Concepción Alonso4, Amandine Andrieux-Ledier5, Raul Arenal6, Raul Arenal7, Jon Azpeitia6, Nilanthy Balakrishnan8, Luca Banszerus9, Julien Barjon5, Ruben Bartali10, Sebastiano Bellani11, Claire Berger12, Claire Berger13, Reinhard Berger14, M.M. Bernal Ortega15, Carlo Bernard16, Peter H. Beton8, André Beyer17, Alberto Bianco18, Peter Bøggild19, Francesco Bonaccorso11, Gabriela Borin Barin20, Cristina Botas, Rebeca A. Bueno6, Daniel Carriazo21, Andres Castellanos-Gomez6, Meganne Christian, Artur Ciesielski18, Tymoteusz Ciuk, Matthew T. Cole, Jonathan N. Coleman2, Camilla Coletti11, Luigi Crema10, Huanyao Cun16, Daniela Dasler22, Domenico De Fazio3, Noel Díez, Simon Drieschner23, Georg S. Duesberg24, Roman Fasel25, Roman Fasel20, Xinliang Feng14, Alberto Fina15, Stiven Forti11, Costas Galiotis26, Costas Galiotis27, Giovanni Garberoglio28, Jorge M. Garcia6, Jose A. Garrido, Marco Gibertini29, Armin Gölzhäuser17, Julio Gómez, Thomas Greber16, Frank Hauke22, Adrian Hemmi16, Irene Hernández-Rodríguez6, Andreas Hirsch22, Stephen A. Hodge3, Yves Huttel6, Peter Uhd Jepsen19, I. Jimenez6, Ute Kaiser30, Tommi Kaplas31, HoKwon Kim29, Andras Kis29, Konstantinos Papagelis32, Konstantinos Papagelis26, Kostas Kostarelos33, Aleksandra Krajewska34, Kangho Lee24, Changfeng Li35, Harri Lipsanen35, Andrea Liscio, Martin R. Lohe14, Annick Loiseau5, Lucia Lombardi3, María Francisca López6, Oliver Martin22, Cristina Martín36, Lidia Martínez6, José A. Martín-Gago6, José I. Martínez6, Nicola Marzari29, Alvaro Mayoral7, Alvaro Mayoral37, John B. McManus2, Manuela Melucci, Javier Méndez6, Cesar Merino, Pablo Merino6, Andreas Meyer22, Elisa Miniussi16, Vaidotas Miseikis11, Neeraj Mishra11, Vittorio Morandi, Carmen Munuera6, Roberto Muñoz6, Hugo Nolan2, Luca Ortolani, A. K. Ott38, A. K. Ott3, Irene Palacio6, Vincenzo Palermo39, John Parthenios26, Iwona Pasternak40, Amalia Patanè8, Maurizio Prato21, Maurizio Prato41, Henri Prevost5, Vladimir Prudkovskiy13, Nicola M. Pugno42, Nicola M. Pugno43, Nicola M. Pugno44, Teófilo Rojo45, Antonio Rossi11, Pascal Ruffieux20, Paolo Samorì18, Léonard Schué5, Eki J. Setijadi10, Thomas Seyller46, Giorgio Speranza10, Christoph Stampfer9, I. Stenger5, Wlodek Strupinski40, Yuri Svirko31, Simone Taioli28, Simone Taioli47, Kenneth B. K. Teo, Matteo Testi10, Flavia Tomarchio3, Mauro Tortello15, Emanuele Treossi, Andrey Turchanin48, Ester Vázquez36, Elvira Villaro, Patrick Rebsdorf Whelan19, Zhenyuan Xia39, Rositza Yakimova, Sheng Yang14, G. Reza Yazdi, Chanyoung Yim24, Duhee Yoon3, Xianghui Zhang17, Xiaodong Zhuang14, Luigi Colombo49, Andrea C. Ferrari3, Mar García-Hernández6 
Heidelberg University1, Trinity College, Dublin2, University of Cambridge3, Autonomous University of Madrid4, Université Paris-Saclay5, Spanish National Research Council6, University of Zaragoza7, University of Nottingham8, RWTH Aachen University9, Kessler Foundation10, Istituto Italiano di Tecnologia11, Georgia Institute of Technology12, University of Grenoble13, Dresden University of Technology14, Polytechnic University of Turin15, University of Zurich16, Bielefeld University17, University of Strasbourg18, Technical University of Denmark19, Swiss Federal Laboratories for Materials Science and Technology20, Ikerbasque21, University of Erlangen-Nuremberg22, Technische Universität München23, Bundeswehr University Munich24, University of Bern25, Foundation for Research & Technology – Hellas26, University of Patras27, Center for Theoretical Studies, University of Miami28, École Polytechnique Fédérale de Lausanne29, University of Ulm30, University of Eastern Finland31, Aristotle University of Thessaloniki32, University of Manchester33, Polish Academy of Sciences34, Aalto University35, University of Castilla–La Mancha36, ShanghaiTech University37, University of Exeter38, Chalmers University of Technology39, Warsaw University of Technology40, University of Trieste41, Instituto Politécnico Nacional42, University of Trento43, Queen Mary University of London44, University of the Basque Country45, Chemnitz University of Technology46, Charles University in Prague47, University of Jena48, University of Texas at Dallas49
29 Jan 2020
TL;DR: In this article, the authors present an overview of the main techniques for production and processing of graphene and related materials (GRMs), as well as the key characterization procedures, adopting a 'hands-on' approach, providing practical details and procedures as derived from literature and from the authors' experience, in order to enable the reader to reproduce the results.
Abstract: © 2020 The Author(s). We present an overview of the main techniques for production and processing of graphene and related materials (GRMs), as well as the key characterization procedures. We adopt a 'hands-on' approach, providing practical details and procedures as derived from literature as well as from the authors' experience, in order to enable the reader to reproduce the results. Section I is devoted to 'bottom up' approaches, whereby individual constituents are pieced together into more complex structures. We consider graphene nanoribbons (GNRs) produced either by solution processing or by on-surface synthesis in ultra high vacuum (UHV), as well carbon nanomembranes (CNM). Production of a variety of GNRs with tailored band gaps and edge shapes is now possible. CNMs can be tuned in terms of porosity, crystallinity and electronic behaviour. Section II covers 'top down' techniques. These rely on breaking down of a layered precursor, in the graphene case usually natural crystals like graphite or artificially synthesized materials, such as highly oriented pyrolythic graphite, monolayers or few layers (FL) flakes. The main focus of this section is on various exfoliation techniques in a liquid media, either intercalation or liquid phase exfoliation (LPE). The choice of precursor, exfoliation method, medium as well as the control of parameters such as time or temperature are crucial. A definite choice of parameters and conditions yields a particular material with specific properties that makes it more suitable for a targeted application. We cover protocols for the graphitic precursors to graphene oxide (GO). This is an important material for a range of applications in biomedicine, energy storage, nanocomposites, etc. Hummers' and modified Hummers' methods are used to make GO that subsequently can be reduced to obtain reduced graphene oxide (RGO) with a variety of strategies. GO flakes are also employed to prepare three-dimensional (3d) low density structures, such as sponges, foams, hydro- or aerogels. The assembly of flakes into 3d structures can provide improved mechanical properties. Aerogels with a highly open structure, with interconnected hierarchical pores, can enhance the accessibility to the whole surface area, as relevant for a number of applications, such as energy storage. The main recipes to yield graphite intercalation compounds (GICs) are also discussed. GICs are suitable precursors for covalent functionalization of graphene, but can also be used for the synthesis of uncharged graphene in solution. Degradation of the molecules intercalated in GICs can be triggered by high temperature treatment or microwave irradiation, creating a gas pressure surge in graphite and exfoliation. Electrochemical exfoliation by applying a voltage in an electrolyte to a graphite electrode can be tuned by varying precursors, electrolytes and potential. Graphite electrodes can be either negatively or positively intercalated to obtain GICs that are subsequently exfoliated. We also discuss the materials that can be amenable to exfoliation, by employing a theoretical data-mining approach. The exfoliation of LMs usually results in a heterogeneous dispersion of flakes with different lateral size and thickness. This is a critical bottleneck for applications, and hinders the full exploitation of GRMs produced by solution processing. The establishment of procedures to control the morphological properties of exfoliated GRMs, which also need to be industrially scalable, is one of the key needs. Section III deals with the processing of flakes. (Ultra)centrifugation techniques have thus far been the most investigated to sort GRMs following ultrasonication, shear mixing, ball milling, microfluidization, and wet-jet milling. It allows sorting by size and thickness. Inks formulated from GRM dispersions can be printed using a number of processes, from inkjet to screen printing. Each technique has specific rheological requirements, as well as geometrical constraints. The solvent choice is critical, not only for the GRM stability, but also in terms of optimizing printing on different substrates, such as glass, Si, plastic, paper, etc, all with different surface energies. Chemical modifications of such substrates is also a key step. Sections IV-VII are devoted to the growth of GRMs on various substrates and their processing after growth to place them on the surface of choice for specific applications. The substrate for graphene growth is a key determinant of the nature and quality of the resultant film. The lattice mismatch between graphene and substrate influences the resulting crystallinity. Growth on insulators, such as SiO2, typically results in films with small crystallites, whereas growth on the close-packed surfaces of metals yields highly crystalline films. Section IV outlines the growth of graphene on SiC substrates. This satisfies the requirements for electronic applications, with well-defined graphene-substrate interface, low trapped impurities and no need for transfer. It also allows graphene structures and devices to be measured directly on the growth substrate. The flatness of the substrate results in graphene with minimal strain and ripples on large areas, allowing spectroscopies and surface science to be performed. We also discuss the surface engineering by intercalation of the resulting graphene, its integration with Si-wafers and the production of nanostructures with the desired shape, with no need for patterning. Section V deals with chemical vapour deposition (CVD) onto various transition metals and on insulators. Growth on Ni results in graphitized polycrystalline films. While the thickness of these films can be optimized by controlling the deposition parameters, such as the type of hydrocarbon precursor and temperature, it is difficult to attain single layer graphene (SLG) across large areas, owing to the simultaneous nucleation/growth and solution/precipitation mechanisms. The differing characteristics of polycrystalline Ni films facilitate the growth of graphitic layers at different rates, resulting in regions with differing numbers of graphitic layers. High-quality films can be grown on Cu. Cu is available in a variety of shapes and forms, such as foils, bulks, foams, thin films on other materials and powders, making it attractive for industrial production of large area graphene films. The push to use CVD graphene in applications has also triggered a research line for the direct growth on insulators. The quality of the resulting films is lower than possible to date on metals, but enough, in terms of transmittance and resistivity, for many applications as described in section V. Transfer technologies are the focus of section VI. CVD synthesis of graphene on metals and bottom up molecular approaches require SLG to be transferred to the final target substrates. To have technological impact, the advances in production of high-quality large-area CVD graphene must be commensurate with those on transfer and placement on the final substrates. This is a prerequisite for most applications, such as touch panels, anticorrosion coatings, transparent electrodes and gas sensors etc. New strategies have improved the transferred graphene quality, making CVD graphene a feasible option for CMOS foundries. Methods based on complete etching of the metal substrate in suitable etchants, typically iron chloride, ammonium persulfate, or hydrogen chloride although reliable, are time- and resourceconsuming, with damage to graphene and production of metal and etchant residues. Electrochemical delamination in a low-concentration aqueous solution is an alternative. In this case metallic substrates can be reused. Dry transfer is less detrimental for the SLG quality, enabling a deterministic transfer. There is a large range of layered materials (LMs) beyond graphite. Only few of them have been already exfoliated and fully characterized. Section VII deals with the growth of some of these materials. Amongst them, h-BN, transition metal tri- and di-chalcogenides are of paramount importance. The growth of h-BN is at present considered essential for the development of graphene in (opto) electronic applications, as h-BN is ideal as capping layer or substrate. The interesting optical and electronic properties of TMDs also require the development of scalable methods for their production. Large scale growth using chemical/physical vapour deposition or thermal assisted conversion has been thus far limited to a small set, such as h-BN or some TMDs. Heterostructures could also be directly grown.

330 citations


Cites background or methods from "Raman spectrum of graphene and grap..."

  • ...The Hansen solubility parameters of each material in dispersion were studied in order to discriminate SLG from the rest of materials (FLG, poorly exfoliated carbon fibres and melamine) after the milling treatment....

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  • ...For the highest annealing T (830 °C), the same features as known for singlelayer graphene prepared by mechanical exfoliation (G peak at 1587 cm−1 and a narrow Lorentzian 2D peak at 2680 cm−1 (FWHM = 24 cm−1) [105] are observed after the conversion....

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  • ...Although there is a compromise between exfoliation quality and graphene concentration, these wet conditions follow the same trend established by the Hansen solubility parameters permitting SLG dispersion [135]....

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  • ...Further characterization of the transport properties at low T (T = 0.3 K) in a magnetic field of 15 T demonstrates that by varying the charge density with the back-gate voltage, Shubnikov - de Haas oscillations and resistivity plateaus of the quantum Hall effect specific for SLG are observed [88]....

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  • ...This allows one to select a suitable solvent to disperse mainly SLGs [135]....

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Journal ArticleDOI
TL;DR: This work combines two direct imaging techniques, dark-field transmission electron microscopy (DF-TEM) and widefield Raman imaging, to establish a robust, one-to-one correlation between twist angle and Raman intensity in twisted bilayer graphene (tBLG).
Abstract: Few-layer graphene is a prototypical layered material, whose properties are determined by the relative orientations and interactions between layers. Exciting electrical and optical phenomena have been observed for the special case of Bernal-stacked few-layer graphene, but structure–property correlations in graphene which deviates from this structure are not well understood. Here, we combine two direct imaging techniques, dark-field transmission electron microscopy (DF-TEM) and widefield Raman imaging, to establish a robust, one-to-one correlation between twist angle and Raman intensity in twisted bilayer graphene (tBLG). The Raman G band intensity is strongly enhanced due to a previously unreported singularity in the joint density of states of tBLG, whose energy is exclusively a function of twist angle and whose optical transition strength is governed by interlayer interactions, enabling direct optical imaging of these parameters. Furthermore, our findings suggest future potential for novel optical and op...

330 citations

Journal ArticleDOI
TL;DR: In this paper, Li foils are simply burned in a CS 2 vapour for the cathode design, which shows promising battery performance and can be used in the commercialization of Li-S batteries.
Abstract: Facile and scalable fabrication of high-performing sulfur cathodes is challenging in the commercialization of Li–S batteries. The authors report a strategy of simply burning Li foils in a CS 2 vapour for the cathode design, which shows promising battery performa…

329 citations

References
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28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1(PfPMP1)与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员,通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

18,940 citations