Journal articles: 'Electrical properties of graphene layer'

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Suh, JY, SE Shin, and DH Bae. "Electrical properties of polytetrafluoroethylene/few-layer graphene composites fabricated by solid-state processing." Journal of Composite Materials 51, no. 18 (October 13, 2016): 2565–73. http://dx.doi.org/10.1177/0021998316674349.

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High electrical performances of polytetrafluoroethylene composites containing few-layer graphenes are established by solid-state processing. Polytetrafluoroethylene and FLG powders are mechanically mixed without solvents at room temperature, and hot-pressed. Few-layer graphenes are attached to the polytetrafluoroethylene powder, and gradually wrap the powder surface during milling with a low milling speed. The few-layer graphene-wrapped polytetrafluoroethylene powders readily facilitate the formation of a continuous few-layer graphene network due to the contact between adjacent few-layer graphene-wrapped powders. The final composites using few-layer graphene-wrapped polytetrafluoroethylene powders include a three-dimensional conducting network. Eventually, the wrapping morphology of the polytetrafluoroethylene/few-layer graphene powder results in a remarkable electrical conductivity of 7353 Sm−1 at 30 vol. %. few-layer graphene loading.

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Shul’zhenko, Alexandr A., Lucyna Jaworska, Alexandr N. Sokolov, Vladislav G. Gargin, and Ludmila A. Romanko. "ELECTRICALLY CONDUCTIVE POLYCRYSTALLINE SUPER HARD MATERIAL BASED ON DIAMOND AND n-LAYER GRAPHENES." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 59, no. 8 (July 17, 2018): 69. http://dx.doi.org/10.6060/tcct.20165908.25y.

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The electrical and physical properties of the electrically conductive super hard material on the basis of polycrystalline diamond and n-layered graphenes obtained at high pressures and temperatures were studied. It was established that the increase in graphene in a polycrystalline diamond compact leads to a sharp decrease in resistance. Wherein the hardness of the samples is slightly inferior to the hardness of diamond poly crystals obtained without the use of graphene.

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Sonde, Sushant, Carmelo Vecchio, Filippo Giannazzo, Rositza Yakimova, Emanuele Rimini, and Vito Raineri. "Local Electrical Properties of the 4H-SiC(0001)/Graphene Interface." Materials Science Forum 679-680 (March 2011): 769–76. http://dx.doi.org/10.4028/www.scientific.net/msf.679-680.769.

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Local current transport across graphene/4H-SiC was studied with nanometric scale lateral resolution by Scanning Current Spectroscopy on both graphene grown epitaxially on 4H-SiC(0001) (EG-SiC) and graphene exfoliated from highly oriented pyrolitic graphite and deposited on 4H-SiC(0001) (DG-SiC). The study revealed that the Schottky barrier height (SBH) of EG/4H-SiC(0001) is lowered by ~0.49eV. This is explained in terms of Fermi-level pinning above the Dirac point in EG due to the presence of positively charged states at the interface between Si face of 4H-SiC and carbon-rich buffer layer. Furthermore, Scanning Capacitance Spectroscopy based method allowed evaluating local electron mean free path (lgr) in graphene. lgr in EG-SiC was observed to be, on average, ~0.4 times that in DG-SiC and exhibited large point-to-point variations due to presence of laterally homogeneous positively charged buffer layer at the interface. However, lgr in graphene on SiC was observed to be larger than on standard SiO2 samples (DG-SiO2), which is explained by better dielectric screening of charged impurities and lower surface polar phonon scattering at the graphene/substrate interface.

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Cunha, Eunice, and Maria Paiva. "Composite Films of Waterborne Polyurethane and Few-Layer Graphene—Enhancing Barrier, Mechanical, and Electrical Properties." Journal of Composites Science 3, no. 2 (April 3, 2019): 35. http://dx.doi.org/10.3390/jcs3020035.

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Graphene has excellent mechanical, thermal, and electrical properties. Graphene can serve as potential reinforcement in polymer-based nanocomposites. In order to achieve this goal, graphene has to be distributed homogeneously and dispersed throughout the polymer matrix, establishing a strong interface with the polymer. Solution mixing is an interesting method for the preparation of homogeneous nanocomposites, in particular when using environmentally friendly solvents such as water. The major difficulty met in the production of graphene/polymer composites concerns the preparation and stabilization of graphene in aqueous suspension. In the present work three different graphite-based materials, with different crystallinity and purity grades, were exfoliated in aqueous solution of an amphiphilic pyrene derivative, forming few-layer graphene (FLG). The FLG prepared was dispersed in waterborne polyurethane (WPU) to produce composite films. The composite films were produced by solvent casting and spray coating, forming free-standing films that were characterized in terms of its distribution of FLG through the composite, its permeability to water vapor, its electrical resistivity, and its mechanical properties. The studies demonstrated the influence of different factors on the composite film properties such as the use of graphite vs. FLG, the FLG lateral dimensions, and the FLG composition and composite preparation method.

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Gholamalizadeh, Naghmeh, Saeedeh Mazinani, Majid Abdouss, Ali Mohammad Bazargan, and Fataneh Fatemi. "Efficient and Direct Exfoliation of High-Quality Graphene Layers in Water from Different Graphite Sources and Its Electrical Characterization." Nano 16, no. 07 (June 24, 2021): 2150079. http://dx.doi.org/10.1142/s179329202150079x.

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Green and efficient mass production of graphene sheets with high quality and electrical conductivity is intriguing for both academic scientists and industry. Among numerous production methods suffering from complexity or harsh chemical media, direct and high-yield exfoliation of graphite in water seems to be the best choice. In this study, efforts were made to prepare high-quality and stable graphene dispersions with the highest possible concentrations through an ultrasound-assisted liquid-phase exfoliation (LPE) in water directly from two types of natural graphites. The rigorous structural, morphological and electrical analyses were conducted on both graphite and graphene samples to quantitatively identify the effect of graphite sources on the LPE yield and the quality of the graphene nanosheets produced in the presence of an ionic surfactant. The results obtained by TEM, AFM, XRD and Raman spectroscopy indicated the successful and efficient production of single and few layer graphene sheets with the remarkable concentration of 3.18[Formula: see text]mg.ml[Formula: see text] in water. Moreover, the results signified that the structural quality, electrical conductivity and production yield of the graphene layers undoubtedly depend on the structural properties of graphite source. In fact, the graphite source greatly influences the final properties and potential applications of the produced graphene layer and the results are so important for the future graphene industry.

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Iqbal, M. Z., M. F. Khan, M. W. Iqbal, and Jonghwa Eom. "Tuning the electrical properties of exfoliated graphene layers using deep ultraviolet irradiation." J. Mater. Chem. C 2, no. 27 (2014): 5404–10. http://dx.doi.org/10.1039/c4tc00522h.

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Deep ultraviolet irradiation tunes the electronic properties of mechanically exfoliated single-layer graphene, bilayer graphene, and trilayer graphene while maintaining their unique band structure and electrical properties.

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Kim, Yeon Jae, Dong Hyun Kim, Jung Soo Kim, Jae Ho Jang, Uoo Chang Jung, and Dae Geun Nam. "Electro and Surface Properties of Graphene-Modified Stainless Steel for PEMFC Bipolar Plates." Advanced Materials Research 905 (April 2014): 167–70. http://dx.doi.org/10.4028/www.scientific.net/amr.905.167.

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Chemical converted graphene (CCG) were coated on 316L stainless steel as a bipolar plate which is a component of proton exchange membrane fuel cell (PEMFC) by electro spray coating (ESC). Scanning electron microscope (SEM) and X-ray diffraction (XRD) were used to examine the thickness and surface properties of coating layer. Electrochemical potentiodynamic test was conducted in acidic atmosphere (0.1N H2SO4+2ppm F-) at 80°C using Versastat 4 and analysis program for corrosion resistance measurement. After packing bipolar plates for PEMFC stack, the electrical performances of graphite, bare SS316L and graphene coated SS316L bipolar plates were evaluated by PEMFC evaluating device. The chemical converted graphene was founded on the surface of coated SS316L, and the thickness was 12μm. Graphene coated bipolar plate showed high corrosion resistance of 1.32×10-7A/cm2beside bare SS316L bipolar plate. In electrical performance evaluation, the graphene coated bipolar plate was shown 0.978V on Voc and 0.5A/m2on the reduction potential (0.6V). Although the electrical performance of the graphene coated bipolar plate is lower than graphite bipolar plate, the thickness and weight is lower than graphite bipolar plate. These advantages can enable the PEMFC system more efficiently and economically.

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Schmidt, U., T. Dieing, W. Ibach, and O. Hollricher. "A Confocal Raman-AFM Study of Graphene." Microscopy Today 19, no. 6 (October 28, 2011): 30–33. http://dx.doi.org/10.1017/s1551929511001192.

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The discovery by Novoselov and Geim of a simple method to transfer a single atomic layer of carbon from the c-face of graphite to a substrate suitable for measurements of its electrical and optical properties has led to an increased interest in studying and employing two-dimensional model systems. An overview of electron and phonon properties of graphene and their relationship to the one-dimensional form of carbon known as nanotubes can be found in. The unique chemical, mechanical, electrical, and optical properties of graphene lead to its many application possibilities such as: single molecule detectors, high-strength low-weight new materials, design of new semiconductor devices, etc.

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Liu, Li-Hong, Gopichand Nandamuri, Raj Solanki, and Mingdi Yan. "Electrical Properties of Covalently Immobilized Single-Layer Graphene Devices." Journal of Nanoscience and Nanotechnology 11, no. 2 (February 1, 2011): 1288–92. http://dx.doi.org/10.1166/jnn.2011.3886.

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Li, Xiaomeng, Xiufang Chen, Xiangang Xu, Xiaobo Hu, and Zhiyuan Zuo. "Enhanced Performance of a Visible Light Detector Made with Quasi-Free-Standing Graphene on SiC." Materials 12, no. 19 (October 2, 2019): 3227. http://dx.doi.org/10.3390/ma12193227.

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The excellent optoelectronic properties of graphene give it great potential for applications in optical detection. Among the graphenes obtained through many synthetic methods, epitaxial graphene obtained by thermal decomposition on silicon carbide has remarkable advantages for preparing photodetectors. In this research, epitaxial graphene has been successfully prepared on a silicon surface (0001) of semi-insulating 4H-SiC substrate with a size of 10 mm × 10 mm and epitaxial graphene has been converted to quasi-free-standing graphene by hydrogen passivation. Two metal-graphene-metal photodetectors were fabricated using the two types of graphenes above and the photo-absorption properties of detectors have been investigated under 650-nm laser illumination with different illumination powers. From a comparison of the performances between the two detectors, it was found that a photodetector fabricated with quasi-free-standing graphene shows enhanced performance under a light power of 0.018 mW. Responsivity and external quantum efficiency reach maxima of 5.11 A/W and 9.74%, respectively. This dramatic improvement is mainly due to the disappearance of the buffer layer in epitaxial graphene, providing a new method to achieve optimization of graphene-based opto-electrical devices.

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KUMAR, AMIT, J. M. POUMIROL, W. ESCOFFIER, M. GOIRAN, B. RAQUET, and J. M. BROTO. "ELECTRONIC PROPERTIES OF GRAPHENE, FEW-LAYER GRAPHENE, AND BULK GRAPHITE UNDER VERY HIGH MAGNETIC FIELD." International Journal of Nanoscience 10, no. 01n02 (February 2011): 43–47. http://dx.doi.org/10.1142/s0219581x11007703.

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In the present work, we report on the magneto-transport properties of graphitic based materials (graphene, few-layer graphene, and bulk graphite) in very high magnetic field. Quantum Hall Effect (QHE) has been studied in graphitic systems in very high pulsed magnetic field (up to B = 57 T ) and at low temperature (≤ 4 K). Graphene sample shows well-defined Hall resistance plateaus at filling factors v = 2,6,10, etc. Few-layer graphene systems display clear signatures of standard and unconventional QHE. Magneto-transport studies on bulk highly oriented pyrolytic graphite show a charge density wave transition at strong enough magnetic field as well as Hall coefficient sign reversal.

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Siyar, Muhammad, Asghari Maqsood, and Sadaf Khan. "Synthesis of mono layer graphene oxide from sonicated graphite flakes and their Hall effect measurements." Materials Science-Poland 32, no. 2 (June 1, 2014): 292–96. http://dx.doi.org/10.2478/s13536-013-0189-2.

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AbstractGraphene, a single atom thick sheet is considered a key candidate for the future nanotechnology, due to its unique extraordinary properties. Researchers are trying to synthesize bulk graphene via chemical route from graphene oxide precursor. In the present work, we investigated a safe and efficient way of monolayer graphene oxide synthesis. To get a high degree of oxidation, we sonicated the graphite flakes before oxidation. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) results confirmed graphene oxide formation and high degree of oxidation. Raman spectroscopy and atomic force microscopy (AFM) results revealed a monolayer of graphene oxide (GO) flakes. The sheet like morphology of the GO flakes was further confirmed by scanning electron microscopy (SEM). The Hall effect measurements were performed on the GO film on a silica substrate to investigate its electrical properties. The results obtained, revealed that the GO film is perfectly insulating, having electrical resistivity up to 8.4 × 108 (Ω·cm) at room temperature.

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Nikolaev, Danil Valeriyevich, Zakhar Ivanovich Evseev, Svetlana Afanasyevna Smagulova, and Irina Veniaminovna Antonova. "Electrical Properties of Textiles Treated with Graphene Oxide Suspension." Materials 14, no. 8 (April 16, 2021): 1999. http://dx.doi.org/10.3390/ma14081999.

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Two-dimensional nanomaterials such as graphene can provide various functional properties to textiles, which have great potential in sportswear, healthcare etc. In this study, the properties of nylon and cotton-based electronic textiles coated with reduced graphene oxide are investigated. After reduction of graphene oxide coating in hydrazine vapor, e-textiles with a resistance of ~350 Ω/sq for nylon, and ~1 kΩ/sq for cotton were obtained. Cyclic mechanical bending tests of samples showed that the resistance increases during bending up to 10–20%. The use of bovine serum albumin as an adhesive layer improved the wash stability for samples with nylon up to 40 washing cycles. The use of BF-6 glue as a protective layer reduced changes in resistance during bending, and improved wash stability of cotton samples. It was shown that the resistance of the obtained samples is sensitive to changes in temperature and humidity. In addition, obtained e-textiles attached to a person’s wrist were able to measure heart rate. Thus, the obtained electronic textiles based on cotton and nylon coated with reduced graphene oxide demonstrates good characteristics for use as sensors for monitoring vital signs.

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Hanzel, Ondrej, Zoltán Lenčéš, Peter Tatarko, Richard Sedlák, Ivo Dlouhý, Ján Dusza, and Pavol Šajgalík. "Preparation and Properties of Layered SiC-Graphene Composites for EDM." Materials 14, no. 11 (May 28, 2021): 2916. http://dx.doi.org/10.3390/ma14112916.

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Three and five-layered silicon carbide-based composites containing 0, 5, and 15 wt.% of graphene nanoplatelets (GNPs) were prepared with the aim to obtain a sufficiently high electrical conductivity in the surface layer suitable for electric discharge machining (EDM). The layer sequence in the asymmetric three-layered composites was SiC/SiC-5GNPs/SiC-15GNPs, while in the symmetric five-layered composite, the order of layers was SiC-15GNPs/SiC-5GNPs/SiC/SiC-5GNPs/SiC-15GNPs. The layered samples were prepared by rapid hot-pressing (RHP) applying various pressures, and it was shown that for the preparation of dense 3- or 5-layered SiC/GNPs composites, at least 30 MPa of the applied load was required during sintering. The electrical conductivity of 3-layered and 5-layered composites increased significantly with increasing sintering pressure when measured on the SiC surface layer containing 15 wt.% of GNPs. The increasing GNPs content had a positive influence on the electrical conductivity of individual layers, while their instrumented hardness and elastic modulus decreased. The scratch tests confirmed that the materials consisted of well-defined layers with straight interfaces without any delamination, which suggests good adhesion between the individual layers.

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Lago, Emanuele, Peter S. Toth, Giammarino Pugliese, Vittorio Pellegrini, and Francesco Bonaccorso. "Solution blending preparation of polycarbonate/graphene composite: boosting the mechanical and electrical properties." RSC Advances 6, no. 100 (2016): 97931–40. http://dx.doi.org/10.1039/c6ra21962d.

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The preparation of polycarbonate-based graphene composites is reported. The loading of single- and few-layer graphene flakes improves the mechanical and thermal properties, as well as the electrical conductivity of the polymer.

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Ryu, Hyung, Hong-Seok Kim, Daeyoon Kim, Sang Lee, Wonjoon Choi, Sang Kwon, Jae-Hee Han, and Eou-Sik Cho. "Understanding of the Mechanism for Laser Ablation-Assisted Patterning of Graphene/ITO Double Layers: Role of Effective Thermal Energy Transfer." Micromachines 11, no. 9 (August 29, 2020): 821. http://dx.doi.org/10.3390/mi11090821.

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Demand for the fabrication of high-performance, transparent electronic devices with improved electronic and mechanical properties is significantly increasing for various applications. In this context, it is essential to develop highly transparent and conductive electrodes for the realization of such devices. To this end, in this work, a chemical vapor deposition (CVD)-grown graphene was transferred to both glass and polyethylene terephthalate (PET) substrates that had been pre-coated with an indium tin oxide (ITO) layer and then subsequently patterned by using a laser-ablation method for a low-cost, simple, and high-throughput process. A comparison of the results of the laser ablation of such a graphene/ITO double layer with those of the ITO single-layered films reveals that a larger amount of effective thermal energy of the laser used is transferred in the lateral direction along the graphene upper layer in the graphene/ITO double-layered structure, attributable to the high thermal conductivity of graphene. The transferred thermal energy is expected to melt and evaporate the lower ITO layer at a relatively lower threshold energy of laser ablation. The transient analysis of the temperature profiles indicates that the graphene layers can act as both an effective thermal diffuser and converter for the planar heat transfer. Raman spectroscopy was used to investigate the graphite peak on the ITO layer where the graphene upper layer was selectively removed because of the incomplete heating and removal process for the ITO layer by the laterally transferred effective thermal energy of the laser beam. Our approach could have broad implications for designing highly transparent and conductive electrodes as well as a new way of nanoscale patterning for other optoelectronic-device applications using laser-ablation methods.

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Tan, Kai Jian, and Zhan Bo Yu. "Preparation and Characterization of Scalable and Multi-Functional High Conductivity Polymer Electrode Material." Advanced Materials Research 898 (February 2014): 64–67. http://dx.doi.org/10.4028/www.scientific.net/amr.898.64.

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High conductive and polymer composite has good electrical, mechanical and electrochemical properties which is a scalable, multi-functional composite material. It is widely used in electric vehicles, power storage and military fields. This article treats graphene as the working electrode self-supporting film and prepares the structures of the reduction of graphene-polypyrrole-Sulfonated graphene three-layer composite membrane using Polypyrrole electrochemical deposition method. From the electricity microscope, we can observe that the composite film have a closely structure which improves the electrical conductivity and mechanical properties of highly conductive polymer material. Finally, this paper studies the electrical properties of the composite film by the way of electrical experiment. From the experiment, we can conclude that in the voltage driver of 1V, the composite film has a better driving performance which can reach a rate of 198 / s. Its cycle life is up to 8000 times. This provides a new method for preparation and study of graphene conductive polymer composite.

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Wang, Jiaqi, Zhenzhou Cheng, and Xuejin Li. "Progress on Waveguide-Integrated Graphene Optoelectronics." Advances in Condensed Matter Physics 2018 (May 20, 2018): 1–9. http://dx.doi.org/10.1155/2018/9324528.

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Graphene, a single layer of carbon atoms arranged in the form of hexagonal lattice, has many intriguing optical and electrical properties. However, due to the atomic layer thickness, light-matter interactions in the monolayer graphene are naturally weak when the light is normally incident to the material. To overcome this challenge, waveguide-integrated graphene optoelectronic devices have been proposed and demonstrated. In such coplanar configurations, the propagating light in the waveguide can significantly interact with the graphene layer integrated on the surface of the waveguide. The combination of photonic integrated circuits and graphene also enables the development of graphene devices by using silicon photonic technology, which greatly extends the scope of graphene’s application. Moreover, the waveguide-integrated graphene devices are fully CMOS-compatible, which makes it possible to achieve low-cost and high-density integration in the future. As a result, the area has been attracting more and more attention in recent years. In this paper, we introduce basic principles and research advances of waveguide-integrated graphene optoelectronics.

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Slepchenkov, Michael M., Pavel V. Barkov, and Olga E. Glukhova. "In Silico Study of the Electrically Conductive and Electrochemical Properties of Hybrid Films Formed by Bilayer Graphene and Single-Wall Nanotubes under Axial Stretching." Membranes 11, no. 9 (August 26, 2021): 658. http://dx.doi.org/10.3390/membranes11090658.

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Using the self-consistent-charge density-functional tight-binding (SCC-DFTB) method, we studied the effect of axial stretching on the electrical conductivity and quantum capacitance of hybrid films formed by AB-stacked bilayer graphene and horizontally oriented single-walled carbon nanotubes (SWCNTs) with indices chirality (12, 6). The paper discusses several topological models of hybrid graphene/SWCNT (12, 6) films, which differ in the width of the graphene layer in the supercell and in the value of the shift between the graphene layers. It is shown that axial stretching has a different effect on the electrical conductivity and quantum capacity of the hybrid graphene/SWCNT (12, 6) film depending on the width of the graphene layer. For a topological model with a minimum width of the graphene layer (2 hexagons) under a 10% stretching strain, the transformation of bilayer graphene from planar to wave-like structures is characteristic. This transformation is accompanied by the appearance of the effect of anisotropy of electrical conductivity and a sharp decrease in the maximum of quantum capacitance. For a topological model with a graphene layer width of 4 hexagons, axial stretching, on the contrary, leads to a decrease in the effect of anisotropy of electrical conductivity and insignificant changes in the quantum capacitance. Based on the obtained results, the prospects for using hybrid graphene/SWCNT (12, 6) films as a material for creating flexible electrodes of supercapacitors are predicted.

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Seenithurai, Sonai, Ramalingam Kodi Pandyan, Shanmugam Vinodh Kumar, and Manickam Mahendran. "Electronic Properties of Boron and Nitrogen Doped Graphene." Nano Hybrids 5 (October 2013): 65–83. http://dx.doi.org/10.4028/www.scientific.net/nh.5.65.

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Graphene is the thinnest 2-D material which can be regarded as a single layer of graphite. The unique electrical, mechanical and optical properties of graphene can be used in many technological applications. 2-D nanomaterials with semiconducting properties are of great interest since they can be applied in electronics industry. Pure graphene is a zerogap semiconductor or semimetal, since the electron states just cross the Fermi energy. However, the electronic properties of graphene can be tuned by doping boron or nitrogen atoms. Understanding the electronic properties in terms of density of states and band structure of doped graphene is of great relevance today. In our work, we have analyzed the electronic properties of boron and nitrogen doped graphene using Density Functional Theory (DFT). The stability and charge analysis of doped structures have been studied. The Local Density Approximation (LDA) calculations have been used to find the total energies of the structures. In addition to the electronics industry, doped graphene also has great potential to adsorb gas molecules. Therefore, we have analyzed the H2 molecule adsorption in pure, B-doped and N-doped graphene.

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Kang, Chun Hong, Mari Paz Eyang Mba Obama, Mohamed Shuaib Mohamed Saheed, Norani Muti Mohamed, and Zainal Arif Burhanudin. "Facile Formation of Interconnected Multi-Walled Carbon Nanotube-Graphene Nanocomposite for Nanoelectronics Applications." Key Engineering Materials 744 (July 2017): 433–37. http://dx.doi.org/10.4028/www.scientific.net/kem.744.433.

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Novel nanocomposite made of one-dimensional (1-D) multi-walled carbon nanotube (MWCNT) and two-dimensional (2-D) graphene was prepared. MWCNT was spin coated onto copper foil and followed by chemical vapor deposition (CVD) growth of graphene. The MWCNT-Graphene nanocomposite was transferred onto target substrate by using a standard polymer-based transfer technique. HRTEM and Raman spectroscopy showed high crystallinity of fused MWCNT and graphene layer. Low defect-related D-peak was also observed even after the nanocomposite underwent high temperature processing. As compared to pristine graphene, electrical characterization of MWCNT-Graphene nanocomposite also revealed the reduction of sheet resistance by ~71% and almost 2-fold improvement in room-temperature carrier mobility. These improvements are surmised due to additional conducting channels formed by MWCNT in the graphene layer. Hence, higher electrical conductivity can be expected. With the introduction of MWCNT across the graphene layer, highly desirable electrical properties can be achieved and as such leveraging the viability of graphene-based nanoelectronics devices.

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Walters, Ffion, Muhammad Munem Ali, Gregory Burwell, Sergiy Rozhko, Zari Tehrani, Ehsaneh Daghigh Ahmadi, Jon E. Evans, et al. "A Facile Method for the Non-Covalent Amine Functionalization of Carbon-Based Surfaces for Use in Biosensor Development." Nanomaterials 10, no. 9 (September 10, 2020): 1808. http://dx.doi.org/10.3390/nano10091808.

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Affinity biosensors based on graphene field-effect transistor (GFET) or resistor designs require the utilization of graphene’s exceptional electrical properties. Therefore, it is critical when designing these sensors, that the electrical properties of graphene are maintained throughout the functionalization process. To that end, non-covalent functionalization may be preferred over covalent modification. Drop-cast 1,5-diaminonaphthalene (DAN) was investigated as a quick and simple method for the non-covalent amine functionalization of carbon-based surfaces such as graphene, for use in biosensor development. In this work, multiple graphene surfaces were functionalized with DAN via a drop-cast method, leading to amine moieties, available for subsequent attachment to receptor molecules. Successful modification of graphene with DAN via a drop-cast method was confirmed using X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and real-time resistance measurements. Successful attachment of receptor molecules also confirmed using the aforementioned techniques. Furthermore, an investigation into the effect of sequential wash steps which are required in biosensor manufacture, on the presence of the DAN layer, confirmed that the functional layer was not removed, even after multiple solvent exposures. Drop-cast DAN is thus, a viable fast and robust method for the amine functionalization of graphene surfaces for use in biosensor development.

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Kodu, Margus, Artjom Berholts, Tauno Kahro, Jens Eriksson, Rositsa Yakimova, Tea Avarmaa, Indrek Renge, Harry Alles, and Raivo Jaaniso. "Graphene-Based Ammonia Sensors Functionalised with Sub-Monolayer V2O5: A Comparative Study of Chemical Vapour Deposited and Epitaxial Graphene †." Sensors 19, no. 4 (February 23, 2019): 951. http://dx.doi.org/10.3390/s19040951.

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Graphene in its pristine form has demonstrated a gas detection ability in an inert carrier gas. For practical use in ambient atmosphere, its sensor properties should be enhanced with functionalisation by defects and dopants, or by decoration with nanophases of metals or/and metal oxides. Excellent sensor behaviour was found for two types of single layer graphenes: grown by chemical vapour deposition (CVD) and transferred onto oxidized silicon (Si/SiO2/CVDG), and the epitaxial graphene grown on SiC (SiC/EG). Both graphene samples were functionalised using a pulsed laser deposited (PLD) thin V2O5 layer of average thickness ≈ 0.6 nm. According to the Raman spectra, the SiC/EG has a remarkable resistance against structural damage under the laser deposition conditions. By contrast, the PLD process readily induces defects in CVD graphene. Both sensors showed remarkable and selective sensing of NH3 gas in terms of response amplitude and speed, as well as recovery rate. SiC/EG showed a response that was an order of magnitude larger as compared to similarly functionalised CVDG sensor (295% vs. 31% for 100 ppm NH3). The adsorption site properties are assigned to deposited V2O5 nanophase, being similar for both sensors, rather than (defect) graphene itself. The substantially larger response of SiC/EG sensor is probably the result of the smaller initial free charge carrier doping in EG.

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Assunção, Ivan, Susana Sério, Quirina Ferreira, Nykola Jones, Søren Hoffmann, Paulo Ribeiro, and Maria Raposo. "Graphene Oxide Layer-by-Layer Films for Sensors and Devices." Nanomaterials 11, no. 6 (June 12, 2021): 1556. http://dx.doi.org/10.3390/nano11061556.

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Layer-by-layer films of poly (allylamine hydrochloride) (PAH) and graphene oxide (GO) were characterized, looking at growth with the number of bilayers, morphology, and electrical properties. The PAH/GO films revealed a linear increase in absorbance with the increase in the number of deposited bilayers, allowing the determination that 10.7 ± 0.1 mg m−2 of GO is adsorbed per unit of area of each bilayer. GO absorption bands at 146, 210, 247 and 299 nm, assigned to π-π* and n-π* transitions in the aromatic ring (phenol) and of the carboxylic group, respectively, were characterized by vacuum ultraviolet spectroscopy. The morphological characterization of these films demonstrated that they are not completely uniform, with a bilayer thickness of 10.5 ± 0.7 nm. This study also revealed that the films are composed of GO and/or PAH/GO fibers and that GO is completely adsorbed on top of PAH. The electrical properties of the films reveal that PAH/GO films present a semiconductor behavior. In addition, a slight decrease in conduction was observed when films were prepared in the presence of visible light, likely due to the presence of oxygen and moisture that contributes to the damage of GO molecules.

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Jobst, Johannes, Daniel Waldmann, Konstantin V. Emtsev, Thomas Seyller, and Heiko B. Weber. "Transport Properties of Single-Layer Epitaxial Graphene on 6H-SiC (0001)." Materials Science Forum 645-648 (April 2010): 637–41. http://dx.doi.org/10.4028/www.scientific.net/msf.645-648.637.

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We report on electrical measurements on epitaxial graphene on 6H-SiC (0001). The graphene layers were fabricated by thermal decomposition in Argon atmosphere. Large van der Pauw structures and Hall bars were patterned by e-beam lithography, the Hall bars ranged from rather large structures down to sub-micrometer sized Hall bars entirely placed on atomically °at substrate terraces. We present Hall measurements in a broad temperature range, Shubnikov de Haas oscillations and quantum Hall steps. The data lead to the conclusion that electrons in epitaxial graphene have the same quasi-relativistic properties previously shown in exfoliated graphene. A remarkable di®erence, however, is the stronger coupling to substrate phonons and the relatively high charging being an intrinsic property of this epitaxial system.

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Zhu, Jia Yi, and Jun Hui He. "Fabrication and its Transient Optical Properties of Graphene Thin Films." Materials Science Forum 743-744 (January 2013): 892–902. http://dx.doi.org/10.4028/www.scientific.net/msf.743-744.892.

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Graphene thin films were fabricated via layer-by-layer (LbL) assembly of oppositely charged reduced graphene oxides (RGOs) and benign post-treatment. RGOs dispersions and thin films were characterized by means of transmission electron microscopy, UV-visible absorption spectrophotometer, Raman spectroscopy, and four-point probe. It was found that graphene thin films exhibited a significant increase in electrical conductivity after post-treatment. In addition, post-treatment and film thickness showed an effect on transient optical properties of graphene thin films. The transmittance (800 nm, pulse) of (RGO-PDDA+/RGO-O-)30 film decreased after post-treatment, and the transmittance (800 nm, pulse) of post-treated films decreased with increasing the number of LbL assembled bilayers.

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Niemiec, Barbara, Nikola Lenar, Robert Piech, Krzysztof Skupień, and Beata Paczosa-Bator. "Graphene Flakes Decorated with Dispersed Gold Nanoparticles as Nanomaterial Layer for ISEs." Membranes 11, no. 7 (July 20, 2021): 548. http://dx.doi.org/10.3390/membranes11070548.

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This paper proposes a new type of solid-contact layer based on graphene/gold nanoparticles for ion-selective electrodes. A novel approach to preparing the material for intermediate layer by modifying the graphene flakes by gold nanoparticles is presented. With this approach, we observed a large surface area of material and in consequence high electrical capacitance of electrodes. We have obtained satisfactory results demonstrating that the modification of graphene with gold allows for enhancing electrical and wetting properties of carbon nanomaterial. Electrical capacitance of designed nanocomposite-contacted electrode equals to approximately 280 µF, which in consequence ensures great long-term potential stability defined by the potential drift of 36 μV/h. The modification of graphene with nanoparticles completely changed its wetting properties, as the designed material turned out to be hydrophobic with a water contact angle of 115°. Graphene/gold nanoparticles–contacted electrodes are insensitive to the changing light conditions, exhibiting near-Nernstian response in the potassium concentration range between 10−5.9 M and 10−1 M of K+ ions and may be applied in the pH range between 2 and 10.5.

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Lim, Jae-Young, Hyeon-Sik Jang, Hyun-Jae Yoo, Seung-il Kim, and Dongmok Whang. "Pattern Pick and Place Method for Twisted Bi- and Multi-Layer Graphene." Materials 12, no. 22 (November 13, 2019): 3740. http://dx.doi.org/10.3390/ma12223740.

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Twisted bi-layer graphene (tBLG) has attracted much attention because of its unique band structure and properties. The properties of tBLG vary with small differences in the interlayer twist angle, but it is difficult to accurately adjust the interlayer twist angle of tBLG with the conventional fabrication method. In this study, we introduce a facile tBLG fabrication method that directly picks up a single-crystalline graphene layer from a growth substrate and places it on another graphene layer with a pre-designed twist angle. Using this approach, we stacked single-crystalline graphene layers with controlled twist angles and thus fabricated tBLG and twisted multi-layer graphene (tMLG). The structural, optical and electrical properties depending on the twist angle and number of layers, were investigated using transmission electron microscopy (TEM), micro–Raman spectroscopy, and gate-dependent sheet resistance measurements. The obtained results show that the pick and place approach enables the direct dry transfer of the top graphene layer on the as-grown graphene to fabricate uniform tBLG and tMLG with minimal interlayer contamination and pre-defined twist angles.

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Kumar, Vineet, Anuj Kumar, Dong-Joo Lee, and Sang-Shin Park. "Estimation of Number of Graphene Layers Using Different Methods: A Focused Review." Materials 14, no. 16 (August 16, 2021): 4590. http://dx.doi.org/10.3390/ma14164590.

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Graphene, a two-dimensional nanosheet, is composed of carbon species (sp2 hybridized carbon atoms) and is the center of attention for researchers due to its extraordinary physicochemical (e.g., optical transparency, electrical, thermal conductivity, and mechanical) properties. Graphene can be synthesized using top-down or bottom-up approaches and is used in the electronics and medical (e.g., drug delivery, tissue engineering, biosensors) fields as well as in photovoltaic systems. However, the mass production of graphene and the means of transferring monolayer graphene for commercial purposes are still under investigation. When graphene layers are stacked as flakes, they have substantial impacts on the properties of graphene-based materials, and the layering of graphene obtained using different approaches varies. The determination of number of graphene layers is very important since the properties exhibited by monolayer graphene decrease as the number of graphene layer per flake increases to 5 as few-layer graphene, 10 as multilayer graphene, and more than 10 layers, when it behaves like bulk graphite. Thus, this review summarizes graphene developments and production. In addition, the efficacies of determining the number of graphene layers using various characterization methods (e.g., transmission electron microscopy (TEM), atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectra and mapping, and spin hall effect-based methods) are compared. Among these methods, TEM and Raman spectra were found to be most promising to determine number of graphene layers and their stacking order.

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Kamisan, Ainnur Izzati, Lili Widarti Zainuddin, Ainnur Sherene Kamisan, T. I. T. Kudin, Oskar Hasdinor Hassan, Norhana Abdul Halim, and Muhd Zu Azhan Yahya. "Ultrasonic Assisted Synthesis of Reduced Graphene Oxide in Glucose Solution." Key Engineering Materials 708 (September 2016): 25–29. http://dx.doi.org/10.4028/www.scientific.net/kem.708.25.

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A new carbon material viz. graphene has been attracted an increasing research interest owing to its unique electrical and mechanical properties that is useful for the various device applications. The synthesis of graphene from graphene oxide usually involves harmful chemical reducing agents that are toxic and undesirable to human and the environment. By avoiding the use of toxic and environmentally harmful reductants, we report a green approach to effectively reduce graphene oxide to graphene in glucose solution at room temperature. Graphite oxide was synthesized from graphite powder using modified Hummers’ method. Graphite oxide then further exfoliated to graphene oxide by using ultrasonic irradiation. The mild reduction of graphene oxide is carried out by mixing graphene oxide solution with glucose. The reduction time is varied with 15, 30, 45 and 60 minutes. TEM images provide clear evidence for the formation of few layer graphene. Characterization of theresulting glucose reduced graphene oxide by FTIR indicates the partial removal of oxygen-containing functional groups from the surface of graphene oxide and formation of graphene with defects.

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Ku, Yi-Hang, Lo-Yueh Chang, Hung-Wei Shiu, Yen-Chien Kuo, Shangjr Gwo, Chi-Liang Chen, and Chia-Hao Chen. "Layer-number-dependent Optical and Electrical Properties of Graphene on ZnO." Microscopy and Microanalysis 24, S2 (August 2018): 492–93. http://dx.doi.org/10.1017/s1431927618014691.

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Januszko, Adam, Agnieszka Iwan, Stanislaw Maleczek, Wojciech Przybyl, Iwona Pasternak, Aleksandra Krajewska, and Wlodzimierz Strupinski. "CVD-Graphene-Based Flexible, Thermoelectrochromic Sensor." Journal of Nanomaterials 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/2757590.

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The main idea behind this work was demonstrated in a form of a new thermoelectrochromic sensor on a flexible substrate using graphene as an electrically reconfigurable thermal medium (TEChrom™). Our approach relies on electromodulation of thermal properties of graphene on poly(ethylene terephthalate) (PET) via mechanical destruction of a graphene layer. Graphene applied in this work was obtained by chemical vapor deposition (CVD) technique on copper substrate and characterized by Raman and scanning tunneling spectroscopy. Electrical parameters of graphene were evaluated by the van der Pauw method on the transferred graphene layers onto SiO2 substrates by electrochemical delamination method. Two configurations of architecture of sensors, without and with the thermochromic layer, were investigated, taking into account the increase of voltage from 0 to 50 V and were observed by thermographic camera to define heat energy. Current-voltage characteristics obtained for the sensor with damaged graphene layer are linear, and the resistivity is independent from the current applied. The device investigated under 1000 W/m2 exhibited rise of resistivity along with increased temperature. Flexible thermoelectrochromic device with graphene presented here can be widely used as a sensor for both the military and civil monitoring.

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Nahlik, Josef, Jan Voves, Alexandr Laposa, and Jiri Kroutil. "The Study of Graphene Gas Sensor." Key Engineering Materials 605 (April 2014): 495–98. http://dx.doi.org/10.4028/www.scientific.net/kem.605.495.

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The graphene is suitable for gas sensing applications for its two dimensional char-acter which gives the best possible ratio between sensor surface and volume. The interactionbetween graphene surface and gas molecules can signicantly change the graphene layer trans-port properties. Therefore graphene can serve as a sensitive layer in a gas sensor. This work isconcentrated on the analysis of the conductivity of graphene layer exposed to dierent gases(NH3, CO2 ...). Together with the electrical measurement on the interdigital graphene sensora simulation based on quantum atomistic approach has been performed. We used ATK toolkitby Quantuwise based on density functional theory (DFT) models. The exchange-correlationpotential is approximated within the generalized gradient approximation (GGA). The trans-port properties of the electrode-device- electrode geometry were calculated by means of non-equilibrium Greens function formalism as implemented in ATK. Experimental conductivitychanges are compared with the simulation results.

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Lee, Jin-Ho, Soo-jeong Park, and Jeong-Woo Choi. "Electrical Property of Graphene and Its Application to Electrochemical Biosensing." Nanomaterials 9, no. 2 (February 20, 2019): 297. http://dx.doi.org/10.3390/nano9020297.

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Graphene, a single atom thick layer of two-dimensional closely packed honeycomb carbon lattice, and its derivatives have attracted much attention in the field of biomedical, due to its unique physicochemical properties. The valuable physicochemical properties, such as high surface area, excellent electrical conductivity, remarkable biocompatibility and ease of surface functionalization have shown great potentials in the applications of graphene-based bioelectronics devices, including electrochemical biosensors for biomarker analysis. In this review, we will provide a selective overview of recent advances on synthesis methods of graphene and its derivatives, as well as its application to electrochemical biosensor development. We believe the topics discussed here are useful, and able to provide a guideline in the development of novel graphene and on graphene-like 2-dimensional (2D) materials based biosensors in the future.

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Yan, Zhong, Denis L. Nika, and Alexander A. Balandin. "Thermal properties of graphene and few‐layer graphene: applications in electronics." IET Circuits, Devices & Systems 9, no. 1 (January 2015): 4–12. http://dx.doi.org/10.1049/iet-cds.2014.0093.

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Cataldi, Pietro, Athanassia Athanassiou, and Ilker Bayer. "Graphene Nanoplatelets-Based Advanced Materials and Recent Progress in Sustainable Applications." Applied Sciences 8, no. 9 (August 23, 2018): 1438. http://dx.doi.org/10.3390/app8091438.

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Graphene is the first 2D crystal ever isolated by mankind. It consists of a single graphite layer, and its exceptional properties are revolutionizing material science. However, there is still a lack of convenient mass-production methods to obtain defect-free monolayer graphene. In contrast, graphene nanoplatelets, hybrids between graphene and graphite, are already industrially available. Such nanomaterials are attractive, considering their planar structure, light weight, high aspect ratio, electrical conductivity, low cost, and mechanical toughness. These diverse features enable applications ranging from energy harvesting and electronic skin to reinforced plastic materials. This review presents progress in composite materials with graphene nanoplatelets applied, among others, in the field of flexible electronics and motion and structural sensing. Particular emphasis is given to applications such as antennas, flexible electrodes for energy devices, and strain sensors. A separate discussion is included on advanced biodegradable materials reinforced with graphene nanoplatelets. A discussion of the necessary steps for the further spread of graphene nanoplatelets is provided for each revised field.

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Aguilera Mandujano, A., and J. Serrato Rodriguez. "Synthesis and characterization of titania/graphene nanocomposite for application in photocatalysis." Revista Mexicana de Física 66, no. 5 Sept-Oct (September 1, 2020): 610. http://dx.doi.org/10.31349/revmexfis.66.610.

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Titanium dioxide has been extensively investigated as a photocatalyst for water purification, presenting limitations such as recombination of electron-hole pairs generated by photons. The titania / graphene nanocomposites are promising materials to overcome these limitations due to the high specific area of graphene and unique electronic properties. In this work, an anatase-graphene nanocomposite was synthesized by a simple mixture assisted by ultrasound. Graphene was obtained by electrochemical exfoliation of graphite using the electrolysis technique. On the other hand, anatase was synthesized using the sol gel method. The obtained graphene, anatase and the nanocomposite material, were characterized with the X-ray diffraction technique (DRX), scanning electron microscopy (MEB) and transmission electron microscopy (MET). Using Raman spectroscopy, it was possible to verify that the graphite exfoliated correctly producing few layer-graphene. The lamellar nano-structure of the exfoliated graphite has crystallographic planes characteristic of graphite, graphene and graphene oxide. The presence of the anatase phase is shown in the diffraction spectrum of titania. The images obtained with SEM and TEM of the graphene sample show a layered lamellar structure and the TiO2 images show agglomerates of ellipsoidal nanoparticles. Obtained titania nanoparticles have a size of about 6 nm. Band gap value for such extremely low particle size nanocomposite is around 3.6 eV and presumably corresponds to the TiO2 (anatase) phase that completely surrounds the graphene. A nanocomposite model based on HRTEM observations is proposed. Considering the graphene electrical properties and the photocatalytic properties of TiO2, this nanocomposite promises to have applications in photocatalysis.

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Tong, Xinru, Zhuo Zhao, Junsheng Wu, Yanwen Zhou, Peter Kelly, and Peng Gao. "Growth of GaN by Vacuum Thermal Evaporation on Flexible Graphene/PET Substrates." Nanoscience and Nanotechnology Letters 10, no. 3 (March 1, 2018): 329–36. http://dx.doi.org/10.1166/nnl.2018.2666.

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The formation of GaN/graphene hybrid films through the vacuum thermal evaporation of GaN on a double layer flexible substrate consisting of a graphene layer on PET, has been studied. The thicknesses of the GaN layers and, therefore, the structure and properties of the hybrid films, were critically influenced by the deposition time. The structure of the GaN layer on graphene was amorphous, according to small angle X-ray diffraction spectra. The existence of the GaN layer on top of the graphene and the absence of a N–C covalent bond at the interface of the GaN/graphene hybrid film was confirmed by using Fourier transform infrared spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The free π-electrons of graphene took the conductive role in the hybrid films. A slight change in electrical properties was observed with increasing thickness of the GaN layer, due to the shunt resistance between this layer and the graphene layer. The grain size of the GaN films increased and transmittance within the visible range decreased with increasing deposition time, i.e., increasing thickness. The method presented demonstrates the feasibility of realizing transparent conductive GaN/graphene hybrid films on flexible PET, which are in high demand for fabricating optoelectronic and sensing devices.

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Nowakowski, Krystian, Rik van Bremen, Harold J. W. Zandvliet, and Pantelis Bampoulis. "Control of the metal/WS2 contact properties using 2-dimensional buffer layers." Nanoscale 11, no. 12 (2019): 5548–56. http://dx.doi.org/10.1039/c9nr00574a.

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In order to precisely control current flow through electrical contacts to WS₂, MoSe₂ and graphene were used as thin interfacial buffer layers. As shown by spatially-resolved conductive-AFM data, the barrier heights are tunable with MoSe₂ buffer layer thickness, while graphene enhances transport by depinning the Fermi level.

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Puthirath, Anand B., Sharmila Shirodkar, Minfei Fei, Abhijit Baburaj, Keiko Kato, Sreehari K. Saju, Ranjith Prasannachandran, et al. "Complementary behaviour of EDL and HER activity in functionalized graphene nanoplatelets." Nanoscale 12, no. 3 (2020): 1790–800. http://dx.doi.org/10.1039/c9nr08102j.

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Armano, Angelo, and Simonpietro Agnello. "Two-Dimensional Carbon: A Review of Synthesis Methods, and Electronic, Optical, and Vibrational Properties of Single-Layer Graphene." C — Journal of Carbon Research 5, no. 4 (November 1, 2019): 67. http://dx.doi.org/10.3390/c5040067.

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Graphite has been widely used by humans for a large part of their history. Nevertheless, it has only recently been possible to isolate its basic unit: carbon atoms arranged in a honeycomb structure on a single plane, namely graphene. Since its discovery, many techniques have been developed and improved to properly synthesize graphene and its derivatives which are part of the novel class of two-dimensional materials. These advanced materials have imposed themselves in nanotechnology thanks to some outstanding physical properties due to their reduced dimensions. In the case of graphene, its reduced dimension gives rise to a high electrical mobility, a large thermal conductivity, a high mechanical resistance, and a large optical transparency. Therefore, such aspect is of great scientific interest for both basic and applied research, ranging from theoretical physics to surface chemistry and applied solid state physics. The connection between all these fields is guaranteed by spectroscopy and especially by Raman spectroscopy which provides a lot of information about structural and electronic features of graphene. In this review, the authors present a systematized collection of the most important physical insights on the fundamental electronic and vibrational properties of graphene, their connection with basic optical and Raman spectroscopy, and a brief overview of main synthesis methods.

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Wang, Lei, Wencai Wang, Ye Fu, Junjun Wang, Yuri Lvov, Jun Liu, Yonglai Lu, and Liqun Zhang. "Enhanced electrical and mechanical properties of rubber/graphene film through layer-by-layer electrostatic assembly." Composites Part B: Engineering 90 (April 2016): 457–64. http://dx.doi.org/10.1016/j.compositesb.2015.12.048.

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Barin, Gabriela B., Antonio G. Souza Filho, Ledjane S. Barreto, and Jing Kong. "Pre-Patterned CVD Graphene: Insights on ALD deposition parameters and their influence on Al2O3 and graphene layers." MRS Advances 1, no. 20 (2016): 1401–9. http://dx.doi.org/10.1557/adv.2016.202.

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ABSTRACTFabrication of graphene nanostructures it is important for both investigating their intrinsic physical properties and applying them into various functional devices. In this work we present a study on atomic layer deposition (ALD) of Al2O3 to produce patterned graphene through area-selective chemical vapor deposition (CVD) growth. A systematic parametric study was conducted to determine how the number of cycles and the purging time affect the morphology and the electrical properties of both graphene and Al2O3 layers.

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Nair, Aparna V., and B. Manoj. "Tailoring of Energy Band Gap inGraphene-like System by Fluorination." Mapana - Journal of Sciences 18, no. 1 (January 1, 2019): 55–66. http://dx.doi.org/10.12723/mjs.48.4.

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Fluorinated grapheme has a two-dimensional layer structure with a wide band gap. In the present study, Fluoro Graphene (FG) is obtained from Graphene Oxide (GO) through a deoxyfluorination reaction with the aid of Diethylaminosulphurtrifluoride (DAST). The FT-IR exhibited a peak at 1216 cm-1 and the shoulder at 1312 cm-1 were ascribed to the stretching vibration of covalent C–F bonds and C–F2 bonds, respectively. Surface morphology revealed a leafy structure in GO and a rocky structure in FG. The EDS analysis confirmed the fluorination of the graphitic structure. The TEM analysis confirmed the formation of a mixed structure of graphene and carbon dots. The results of structural, morphological and electrical properties of both graphene oxide and fluorographene show the possibility of using these samples as electronic/electrochemical devices in future.

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Jung, Jae Woong, Seung Hwan Son, and Jun Choi. "Polyaniline/Reduced Graphene Oxide Composites for Hole Transporting Layer of High-Performance Inverted Perovskite Solar Cells." Polymers 13, no. 8 (April 14, 2021): 1281. http://dx.doi.org/10.3390/polym13081281.

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We herein address the optoelectronic properties of polyaniline composite films with graphene oxide and reduced graphene oxide as a hole transport layer in inverted perovskite solar cells. The composite films exhibited enhanced electrical conductivity and suitable energy level matching with CH3NH3PbI3 for efficient hole extraction/transport than the pristine polyaniline film, which thus can deliver improved photovoltaic properties of device. The composite film-based devices exhibited maximum efficiency of 16.61%, which is enhanced by 21.6% from the device with the pristine polyaniline hole transport layer (efficiency = 13.66%). The reduced graphene oxide-based composite film also achieved improved long-term operative stability as compared to the pristine polyaniline-based device, demonstrating a great potential of reduced graphene oxide/polyaniline composite hole transport layer for high performance perovskite solar cells.

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Chang, Hao-Hsun, Tseng-Hsiang Ho, and Yu-Sheng Su. "Graphene-Enhanced Battery Components in Rechargeable Lithium-Ion and Lithium Metal Batteries." C 7, no. 3 (September 16, 2021): 65. http://dx.doi.org/10.3390/c7030065.

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Stepping into the 21st century, “graphene fever” swept the world due to the discovery of graphene, made of single-layer carbon atoms with a hexagonal lattice. This wonder material displays impressive material properties, such as its electrical conductivity, thermal conductivity, and mechanical strength, and it also possesses unique optical and magnetic properties. Many researchers see graphene as a game changer for boosting the performance of various applications. Emerging consumer electronics and electric vehicle technologies require advanced battery systems to enhance their portability and driving range, respectively. Therefore, graphene seems to be a great candidate material for application in high-energy-density/high-power-density batteries. The “graphene battery”, combining two Nobel Prize-winning concepts, is also frequently mentioned in the news and articles all over the world. This review paper introduces how graphene can be adopted in Li-ion/Li metal battery components, the designs of graphene-enhanced battery materials, and the role of graphene in different battery applications.

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Rahman, Md Sazzadur, Rokaia Laizu Naima, Khatuna Jannatun Shetu, Md Mahabub Hossain, M. Shamim Kaiser, A. S. M. Sanwar Hosen, Md Abdul Latif Sarker, and Kelvin J. A. Ooi. "Silicene Quantum Capacitance Dependent Frequency Readout to a Label-Free Detection of DNA Hybridization— A Simulation Analysis." Biosensors 11, no. 6 (June 1, 2021): 178. http://dx.doi.org/10.3390/bios11060178.

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The use of deoxyribonucleic acid (DNA) hybridization to detect disease-related gene expression is a valuable diagnostic tool. An ion-sensitive field-effect transistor (ISFET) with a graphene layer has been utilized for detecting DNA hybridization. Silicene is a two-dimensional silicon allotrope with structural properties similar to graphene. Thus, it has recently experienced intensive scientific research interest due to its unique electrical, mechanical, and sensing characteristics. In this paper, we proposed an ISFET structure with silicene and electrolyte layers for the label-free detection of DNA hybridization. When DNA hybridization occurs, it changes the ion concentration in the surface layer of the silicene and the pH level of the electrolyte solution. The process also changes the quantum capacitance of the silicene layer and the electrical properties of the ISFET device. The quantum capacitance and the corresponding resonant frequency readout of the silicene and graphene are compared. The performance evaluation found that the changes in quantum capacitance, resonant frequency, and tuning ratio indicate that the sensitivity of silicene is much more effective than graphene.

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Nguyen, Dang Du, TaeGyeong Lim, Soomook Lim, and Ji Won Suk. "Interlayer Separation in Graphene Paper Comprising Electrochemically Exfoliated Graphene." Nanomaterials 11, no. 4 (March 29, 2021): 865. http://dx.doi.org/10.3390/nano11040865.

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The emergence of graphene paper comprising well-stacked graphene flakes has promoted the application of graphene-based materials in diverse fields such as energy storage devices, membrane desalination, and actuators. The fundamental properties of graphene paper such as mechanical, electrical, and thermal properties are critical to the design and fabrication of paper-based devices. In this study, the interlayer interactions in graphene paper were investigated by double cantilever beam (DCB) fracture tests. Graphene papers fabricated by flow-directed stacking of electrochemically exfoliated few-layer graphene flakes were mechanically separated into two parts, which generated force-displacement responses of the DCB sample. The analysis based on fracture mechanics revealed that the interlayer separation energy of the graphene paper was 9.83 ± 0.06 J/m2. The results provided a fundamental understanding of the interfacial properties of graphene papers, which will be useful for developing paper-based devices with mechanical integrity.

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Batista, Ronaldo J. C., Rafael F. Dias, Ana P. M. Barboza, Alan B. de Oliveira, Taise M. Manhabosco, Thiago R. Gomes-Silva, Matheus J. S. Matos, et al. "Nanomechanics of few-layer materials: do individual layers slide upon folding?" Beilstein Journal of Nanotechnology 11 (November 30, 2020): 1801–8. http://dx.doi.org/10.3762/bjnano.11.162.

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Folds naturally appear on nanometrically thin materials, also called “2D materials”, after exfoliation, eventually creating folded edges across the resulting flakes. We investigate the adhesion and flexural properties of single-layered and multilayered 2D materials upon folding in the present work. This is accomplished by measuring and modeling mechanical properties of folded edges, which allows for the experimental determination of the bending stiffness (κ) of multilayered 2D materials as a function of the number of layers (n). In the case of talc, we obtain κ ∝ n 3 for n ≥ 5, indicating no interlayer sliding upon folding, at least in this thickness range. In contrast, tip-enhanced Raman spectroscopy measurements on edges in folded graphene flakes, 14 layers thick, show no significant strain. This indicates that layers in graphene flakes, up to 5 nm thick, can still slip to relieve stress, showing the richness of the effect in 2D systems. The obtained interlayer adhesion energy for graphene (0.25 N/m) and talc (0.62 N/m) is in good agreement with recent experimental results and theoretical predictions. The obtained value for the adhesion energy of graphene on a silicon substrate is also in agreement with previous results.

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Liu, Yanping, Zongwen Liu, Wen Lew, and Qi Wang. "Temperature dependence of the electrical transport properties in few-layer graphene interconnects." Nanoscale Research Letters 8, no. 1 (2013): 335. http://dx.doi.org/10.1186/1556-276x-8-335.

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Journal articles on the topic 'Electrical properties of graphene layer'

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