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Synthesis of graphene by various PVD methods: (a) vacuum evaporation, (b) and (c) sputter evaporation, (d) FCVA, (e-g) ion plating, and (h) IBAD.

Synthesis of graphene by various PVD methods: (a) vacuum evaporation, (b) and (c) sputter evaporation, (d) FCVA, (e-g) ion plating, and (h) IBAD.

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A review of graphene synthesis by indirect and direct deposition methods - Volume 35 Issue 1 - Yanxia Wu, Shengxi Wang, Kyriakos Komvopoulos

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... whereas the PVD methods provide high purity, low temperature, high throughput, and controllable growth of graphene on a wide range of substrate materials [31,32]. Depending on the energy source, PVD growth of graphene can be achieved by vacuum evaporation, sputter deposition, cathodic arc, ion plating, and ion beam-assisted deposition (IBAD) (Fig. ...

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... which is not possible with other methods. For more comprehensive information, readers are recommended to consult reviews on graphene synthesis approaches available in the literature [94][95][96][97][98]. Figure 9. Bottom-up and top-down approaches for graphene synthesis [99]. ...
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This review presents a brief overview of the electrical and gas-sensor properties of polyaniline (PANI) and graphene-based nanocomposites with their application as gas detection materials along with underlying sensing mechanisms. Several studies have shown that graphene-based PANI gas sensors perform remarkably well at ambient temperature, energy efficient, and are inexpensive. The electrical and gas sensing properties of PANI/graphene nanocomposites offer improved responsiveness, durability, and other detection capabilities in sensor-based devices at room temperature. Moreover, the electrical conductivity and gas sensor properties may be controlled by the synthesis methods, and the form and type of graphene. This review provides a new framework for the development of new nanomaterials based on PANI/graphene, which will advance their development and industrialization in the environment.
... For obtaining films of graphene species for electrodes, two strategies are usual: the first one is the solution-casting of EGO followed by high-temperature annealing to reduce the GO to RGO [9], another one is the CVD catalyzed by Ni or Cu of pristine graphene [10]. The first method is preferred to achieve coatings, however, the high temperatures required (above 1000 • C) are not suitable for application over flexible substrates [9]. ...
... For obtaining films of graphene species for electrodes, two strategies are usual: the first one is the solution-casting of EGO followed by high-temperature annealing to reduce the GO to RGO [9], another one is the CVD catalyzed by Ni or Cu of pristine graphene [10]. The first method is preferred to achieve coatings, however, the high temperatures required (above 1000 • C) are not suitable for application over flexible substrates [9]. The second method can produce pristine graphene of variable layers [9,10], but the CVD instruments limit for the moment this method to a laboratory-scale level [10]. ...
... The first method is preferred to achieve coatings, however, the high temperatures required (above 1000 • C) are not suitable for application over flexible substrates [9]. The second method can produce pristine graphene of variable layers [9,10], but the CVD instruments limit for the moment this method to a laboratory-scale level [10]. ...
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A graphene composite material suitable for facile drop-casting into flexible, conductive thin film electrodes from aqueous solution under ambient conditions is reported. This composite was applied to a polyethylene terephthalate substrate obtained from soda bottles. A solution of reduced graphene oxide with few layers (∼6 layers) was synthesized. The composites were prepared in two steps, first applying the reduced graphene oxide with surfactant and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) and then, solutions of poly-3-hexylthiophene with three different concentrations. Mild annealing was required only for the first step. The composite films exhibit more stability (mechanical and electrical) in bending tests when an intermediate amount of poly-3-hexylthiophene is applied. This composite is found attractive for flexible optoelectronic applications, promoting the reuse of one-use plastics.
... Los métodos para la síntesis del grafeno se clasifican en dos estrategias distintas: substrato metálico lo hace inviable para su uso en la electrónica sin antes remover el substrato, algo que complejiza aún más el método. (23,24,25,26) ...
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Among the carbon-based compounds is graphene. This is an exceptional material, both from the point of view of fundamental physics research and from the point of view of its practical applications. Graphene occupies a prominent place in science, and the different research carried out is opening up new avenues for the development of functional materials. In this work, the structure of this interesting compound is analyzed. In addition, the chemical, electrical, mechanical and thermal properties are described. On the other hand, the methods used for its synthesis and the techniques used for its characterization are analyzed. Finally, its importance in the creation of new materials with improved properties is discussed, as well as its various applications in different areas of science and technology. These properties also make graphene the ideal material to be applied not only in the field of electronics, but also in medicine, pharmaceuticals, energy, among others. These properties will benefit greatly from this novel bidimensional nanomaterial.
... Physical vapor deposition (PVD) is an essential coating technique that is applied across industries to produce thin-lm layers unto substrates, especially for applications where the source materials naturally exist in solid state. Common types of PVD include sputter deposition [1], electron-beam deposition [2], pulsed later deposition [3], and evaporation deposition. Among the PVD techniques, evaporation PVD is attractive where high deposition rate and simple operating procedures are desired and its main types are vacuum thermal evaporation (VTE) and organic vapor phase deposition (OVPD). ...
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Organic vapor phase deposition (OVPD) is a promising technique for cost-effective manufacture of organic electronic devices. The ability to evenly mix different vapor streams prior to depositing doped emissive layers on the substrate, while maximizing utilization of the source materials is crucial for manufacturing organic light-emitting devices (OLEDs) intended for general lighting. In this work, we numerically and experimentally investigate how process conditions affect critical manufacturing metrics, including vapor mixing, material utilization, and substrate heating during organic vapor deposition. Our results show that hardware aspect ratio needed to achieve effective vapor mixing can be predetermined from vapor transport analyses. We also show that in a diffusion-limited deposition regime, the material utilization efficiency (MUE) is independent of organic vapor concentration and that the ratio of substrate to chamber cross-sectional areas drives MUE. We therefore propose guidelines for the design of OVPD reactors that can deliver > 75% MUE.Graphical abstract Summary illustrating relationship between OVPD conditions, design strategies and studied performance parameters
... Several inorganic and organic materials can be doped or functionalized to create composite materials that give the catalyst a necessary property because of the high surface area and surface chemistry of graphene [30]. ...
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Reduced global warming is the goal of carbon neutrality. Therefore, batteries are considered to be the best alternatives to current fossil fuels and an icon of the emerging energy industry. Voltaic cells are one of the power sources more frequently employed than photovoltaic cells in vehicles, consumer electronics, energy storage systems, and medical equipment. The most adaptable voltaic cells are lithium-ion batteries, which have the potential to meet the eagerly anticipated demands of the power sector. Working to increase their power generating and storage capability is therefore a challenging area of scientific focus. Apart from typical Li-ion batteries, Li-Air (Li-O2) batteries are expected to produce high theoretical power densities (3505 W h kg−1), which are ten times greater than that of Li-ion batteries (387 W h kg−1). On the other hand, there are many challenges to reaching their maximum power capacity. Due to the oxygen reduction reaction (ORR) and oxygen evolution reaction (OES), the cathode usually faces many problems. Designing robust structured catalytic electrode materials and optimizing the electrolytes to improve their ability is highly challenging. Graphene is a 2D material with a stable hexagonal carbon network with high surface area, electrical, thermal conductivity, and flexibility with excellent chemical stability that could be a robust electrode material for Li-O2 batteries. In this review, we covered graphene-based Li-O2 batteries along with their existing problems and updated advantages, with conclusions and future perspectives.
... However, due to the uneven thickness of the graphene flakes and its high production costs, the mechanical exfoliation method was not suitable for the mass production of graphene that might be used to study graphene-based devices. (b) Another method of producing monolayer graphene is the chemical vapour deposition method [62]. Monolayer graphene can be grown epitaxially on a silicon carbide substrate, and can be used for various applications, such as transistors. ...
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The remarkable mechanical, electrical, and thermal capabilities of monolayer graphene make it a wonder substance. As the number of layers in graphene flakes increases to few-layer graphene (number of layers � 5) and multi-layer graphene (number of layers � 10), its properties are affected. In order to obtain the necessary qualities, it is crucial to manage the number of layers in the graphene flake. Therefore, in the current review, we discuss the various processes for producing mono- and few-/multi-layer graphene. The impact of mono-/few-/multi-layer graphene is then assessed with regard to its qualities (including mechanical, thermal, and optical properties). Graphene possesses unique electrical features, such as good carrier mobility, typical ambipolar behaviour, and a unique energy band structure, which might be employed in field effect transistors (FETs) and utilized in radio frequency (RF) circuits, sensors, memory, and other applications. In this review, we cover graphene’s integration into devices for biomolecule detection as well as biomedical applications. The advantages of using graphene in each situation are explored, and samples of the most cutting-edge solutions for biomedical devices and other applications are documented and reviewed.
... The PVD is preferred over CVD due to the achievement of low-temperature use, high yield, and manageable graphene growth on multiple substrate surfaces. In contrast, the CVD method is reported to have sensitive deposition conditions such as growth time, gas concentration, substrate surface, and temperature [109]. ...
... The PVD of graphene may be accomplished via ion plating, sputtering, ion beamassisted growth, and vacuum evaporation [109]. Furthermore, the PVD graphene synthesis can be achieved through direct (growth by utilizing significant energy carbon source and the transitional metallic substrate) and indirect method (deposition through energetic post-growth treatment for amorphous carbon film conversion to graphene structure). ...
... This results in the controlled growth on transitional metal or alloy substrate surface connected to the process chamber cathode. The method set includes arc discharge, laser, unzipping carbon nanotubes, etching, and chemical and mechanical exfoliation [109]. In these methods, the carbon source may be fullerene, graphite, amorphous carbon film, and carbon nanotubes. ...
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Removal of toxic metals is essential to achieving sustainability in wastewater purification. The achievement of efficient treatment at a low cost can be seriously challenging. Adsorption methods have been successfully demonstrated for possession of capability in the achievement of the desirable sustainable wastewater treatment. This review provides insights into important conventional and unconventional materials for toxic metal removal from wastewater through the adsorption process. The importance of the role due to the application of nanomaterials such as metal oxides nanoparticle, carbon nanomaterials, and associated nanocomposite were presented. Besides, the principles of adsorption, classes of the adsorbent materials, as well as the mechanisms involved in the adsorption phenomena were discussed.
... The main processes for the mass production of graphene include the chemical or plasma exfoliation of raw graphite, mechanical cleavage from natural graphite, chemical vapor deposition, or the epitaxial growth of graphene on the silicon face of silicon carbide [7]. It is possible to manufacture graphene from its derivates, by unzipping carbon nanotubes or via the evaporation of fullerene [8]. The most commonly used graphene derivatives, graphene oxide (GO) and reduced GO (rGO), are prepared by the oxidation of graphene. ...
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This review summarizes the current knowledge on current and future applications of carbon nanoparticles in medicine. The carbon nanoparticle family has a large number of representatives with unique physicochemical properties that make them good candidates for use in clinical medicine. The best-known (and most researched) carbon nanoparticles include graphene, graphene oxide, and carbon nanotubes. The main direction of use involves medical diagnostics, which includes bioimaging and the detection of chemicals or metabolites present in the body. Since the question of nanoparticle toxicity has not been fully answered, the use of nanoparticles in the fields of therapeutics (drug delivery), regenerative medicine (cell scaffolding, tissue engineering), and vaccine production is still under research and many in vivo studies are ongoing. These preclinical studies suggest that carbon nanoparticles have great potential for diagnosis and treatment; the results show that the nanoparticles used do not have significant toxic effects; however, great caution is needed before nanoparticles are introduced into routine clinical practice.
... The synthesis of graphene, graphene oxide and rGO has been the subject of numerous reviews [7][8][9][10][11]. However, they address either the pure synthesis of graphene [7,8], the synthesis of graphene and GO [9,10] or the methods of GO reduction [11]. ...
... The synthesis of graphene, graphene oxide and rGO has been the subject of numerous reviews [7][8][9][10][11]. However, they address either the pure synthesis of graphene [7,8], the synthesis of graphene and GO [9,10] or the methods of GO reduction [11]. Our work presents a thorough review of synthesis methods of graphene, GO and also the available routes of reduction of GO. ...
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As nanotechnology floods application areas like medicine, electronics, water remediation, space and textiles, just to name a few, some nanomaterials remain in the spotlight due to their fantastic properties and their incredible potential. Such is the case of the 2D, transparent, flexible, strong, carbon-based nanomaterial called graphene. Graphene consists of sp2 hybridized carbon arranged in a flat network packed in a honey-comb pattern, having thus mono-atomic thickness. Its isolation in 2004 opened the door to numerous investigations and its research is funded each year by governments, industries and academia worldwide. Due to its non-hydrophilic nature, some applications represent a challenge (particularly biological and medical applications), thus an oxygen/hydrogen-functionalized hydrophilic version of it has lately gained popularity, its name is graphene oxide. This document aims to review the synthesis methods of graphene, graphene oxide and reduced graphene oxide. A revision of the most important top-down and bottom-up methods is presented, focusing on chemical vapor deposition for the growth of graphene and the wet-chemical methods for the synthesis of graphene oxide and the reduction techniques available for reduced graphene oxide. We conclude by analyzing the current situation of graphene and graphene oxide production and the challenges that need to be tackled in order to meet the short-term demand of these nanomaterials for the promised applications.
... The unique properties of graphene, including high electronic mobility, mechanical strength, and optical response, are related to its structure [3] and can be controlled by the number of layers and its quality. Therefore, the synthesis and postsynthesis processes play a crucial role in the characteristics of graphene film [4] and its potential applications. Graphene's electromagnetic properties can be tuned via external influences by biasing, optical pumping, and mechanical stresses, thus changing its chemical potential, and adding tunability into the rich palette of graphene's functionalities. ...
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Fragmented multi-layered graphene films were directly synthesized via chemical vapor deposition (CVD) on dielectric substrates with pre-deposited copper catalyst. We demonstrated that the thickness of the sacrificial copper film, process temperature and growth time essentially influence the integrity, quality, and disorder of the synthesized graphene. Atomic Force and Kelvin Probe Force Microscopy measurements revealed the presence of nano-agglomerates and charge puddles. The potential gradients measured over the sample surface confirmed that the deposited graphene film possesses a multilayered structure, which was modelled as an ensemble of randomly oriented conductive prolate ellipsoids. THz time domain spectroscopy measurements gave ac conductivity of graphene flakes and homogenized graphitic films of around 1200 S/cm and 1000 S/cm, respectively. Our approach offers a scalable fabrication of the graphene structures composed of graphene flakes and having effective conductivity sufficient for a wide variety of THz applications.