Kinetic Monte Carlo Modeling of Graphene Sheet Growth During CVD

Graphene is a material of key interest across several research fields. Bulk graphene synthesis, however, has long remained a challenge for larger-scale projects and real-world manufacturability. This work seeks an improved understanding of graphene sheet growth via computational modeling, with the objective of maximizing grain size. To this end, the kinetic Monte Carlo method is used to simulate chemical vapor deposition under various configurations of carbon flow and graphene seeding. Ultimately, both quantitative and qualitative results are obtained to shed light on graphene growth mechanisms, with insights into real-world synthesis and future computational models.

Bio-Based Graphene Sheet/Copolymer Composite as Supporting Material for Nanocatalysts towards Electrochemical Studies and Direct Alkaline Alcohol Fuel Cells

In this work, graphene carbon sheets (BGS) were prepared from writing paper and lemon peel, and its polymer composite has a higher surface area compared with the existing Vulcan carbon. Further, the use of lead as a promoter for the oxidation of alcohol and CO on platinum-supported poly(amine-terminated cyclophosphazene-co-cyclophosphazene)-biobased graphene sheet (Poly(AFCP-co-CP)-BGS) composite was demonstrated. The size, phase morphology, and distribution of metal nanoparticles on Poly(AFCP-co-CP)-BGS composite as well as the formation of composite based catalysts were confirmed from TEM, XRD, and FTIR studies. The catalytic activity and stability of the prepared catalysts were tested and compared to methanol, ethylene glycol, glycerol, and CO in 0.5 M KOH solution. The results conclude that the lead-doped Pt/Poly(AFCP-co-CP)-BGS catalyst shows higher oxidation current with respect to onset potential and lower I f / I r ratio for alcohol as well as CO oxidation. In addition, Pt-Pb/Poly(AFCP-co-CP)-BGS catalyst was checked for direct alkaline fuel cells and proved as a potent anode catalyst in alkaline medium for real-time fuel battery applications. In addition, Poly(AFCP-co-CP)-BGS composite also promotes the catalytic reaction compared to Poly(AFCP-co-CP) and BGS supports as noticed from methanol oxidation in alkaline medium. The surface area of the prepared supporting material is 750.72 m2g-1, which is higher than the activated carbon (250.12m2g-1). So, the prepared Poly(AFCP-co-CP)-BGS composite is a potent support for metal deposition, electrooxidation, and single stack fuel cell constructions.

Co,N-co-doped graphene sheet as a sulfur host for high-performance lithium–sulfur batteries

Design of two-dimensional graphene with dispersed Co–N catalysts as a multifunctional S holding material in Li–S batteries to improve the retention of LiPSs and accelerate the reaction kinetics.

Graphene sheet with periodic vacancy: A first principles study

We present a comprehensive first-principles study of the electronic structure of graphene sheet with periodic vacancy. We report the structural, electronic, and magnetic properties of the graphene sheet with periodic vacancy that possess 48 C & 28 H atoms. Computational analysis based on density functional theory predicts that the periodic vacancy can modulate the properties of graphene sheet. Results show that periodic vacancies lead to the manipulation of band gap & could be utilized to tailor the electronic properties of the sheet. Also, it is found that, the graphene sheet with periodic vacancy is non-magnetic in nature.

Efficient mid-infrared wavelength converter based on plasmon-enhanced nonlinear response in graphene nanoribbons

Graphene plasmons with enhanced localized electric field have been used for boosting the light-matter interaction in linear optical nano-devices. Meanwhile, graphene is an excellent nonlinear material for several third-order nonlinear processes. We present a theoretical investigation of the mechanism of plasmon-enhanced third-order nonlinearity susceptibility of graphene nanoribbons. It is demonstrated that the third-order nonlinearity susceptibility of graphene nanoribbons with excited graphene surface plasmon polaritons can be an order of magnitude larger than the intrinsic susceptibility of a continuous graphene sheet. Combining these properties with the relaxed phase matching condition due to the ultrathin graphene, we propose a novel plasmon-enhanced mid-infrared wavelength converter with arrays of graphene nanoribbons. The wavelength of sig-nal light is in mid-infrared range, which can excite the tunable surface plasmon polaritons in arrays of graphene nanoribbons. The efficiency of the converter from mid-infrared to near-infrared wavelength can be remarkably improved by 60 times compared with the graphene sheet without graphene plasmons. This work provides a novel idea for the efficient application of graphene in the nonlinear optical nano-devices. The proposed mid-infrared wavelength converter is compact, tunable and has promising potential in graphene-based mid-infrared detector with high detection efficiency.

Geometrical Dimensional Effect on Natural Frequency of Single Layer Graphene in Armchair Configuration

Graphene has remarkable strength, such as yield strength and elasticconstant. The dynamic behaviour of graphene sheet is affected bygeometrical variation in atomic arrangement. This paper introducedgraphene with armchair atomic structure for estimating fundamental naturalfrequencies. The presented analysis can be useful for the possible highfrequency nanomechanical resonator systems. The analytical formulation,based on classical plate theory and continuum solid modelling based finiteelement method have been performed for estimation of fundamental naturalfrequencies of single layer graphene sheet (SGLS) with different boundaryconditions. The free edge and clamped edge boundary conditions have beenconsidered. For simplifying analytical formulations, Blevins approach fordynamic solution has been adopted and for validating analytical results.The finite element analysis of SLGS has been performed using ANSYSsoftware. The effect of variation in geometrical parameters in terms ofwidth and length of SLGS has been analysed for realization of ultra-highfrequency based nanomechanical resonator systems

Integrated in Clothes Graphene Antenna with Low SAR for Wearable Body-Centric Communications

The design and fabrication of graphene based textile patch antennas, intended for use in the 2.45GHz ISM band, are presented. The antennas have simple geometries with rectangular, triangular, or circular shape and substrate materials made of four different fabrics suitable for wearable applications. Conductive graphene sheet is used for the active element patches of the twelve different proposed prototypes. The effects of the antenna geometry, the substrate selection and the graphene-textile fabrication process on the prototypes’ performance are studied. Several prototypes exhibit desirable characteristics, such as high gain, acceptable radiation pattern, low Specific Absorption Rate (SAR), relatively wide bandwidth, and coverage of the ISM band even under different bending conditions.