Hybrid Carbon Nanotubes–Graphene Nanostructures: Modeling, Formation, Characterization

Abstract

A technology for the formation and bonding with a substrate of hybrid carbon nanostructures from single-walled carbon nanotubes (SWCNT) and reduced graphene oxide (rGO) by laser radiation is proposed. Molecular dynamics modeling by the real-time time-dependent density functional tight-binding (TD-DFTB) method made it possible to reveal the mechanism of field emission centers formation in carbon nanostructures layers. Laser radiation stimulates the formation of graphene-nanotube covalent contacts and also induces a dipole moment of hybrid nanostructures, which ensures their orientation along the force lines of the radiation field. The main mechanical and emission characteristics of the formed hybrid nanostructures were determined. By Raman spectroscopy, the effect of laser radiation energy on the defectiveness of all types of layers formed from nanostructures was determined. Laser exposure increased the hardness of all samples more than twice. Maximum hardness was obtained for hybrid nanostructure with a buffer layer (bl) of rGO and the main layer of SWCNT—rGO(bl)-SWCNT and was 54.4 GPa. In addition, the adhesion of rGO to the substrate and electron transport between the substrate and rGO(bl)-SWCNT increased. The rGO(bl)-SWCNT cathode with an area of ~1 mm2 showed a field emission current density of 562 mA/cm2 and stability for 9 h at a current of 1 mA. The developed technology for the formation of hybrid nanostructures can be used both to create high-performance and stable field emission cathodes and in other applications where nanomaterials coating with good adhesion, strength, and electrical conductivity is required.

Cold Cathodes with Two-Dimensional van der Waals Materials

“…Based on the above comprehensive review, it is seen that a vertical edge emitter has a high emission efficiency while a surface emitter has a high stability. Depending on the requirement of applications, one may choose a different type of emitter as the cathode Further optimization on their field emission properties may also be performed by using a post-treatment method such as the laser structuring method [105,106]. Apart from the comparison on two types of emitter structures, some perspectives for the future studies o 2D vdW emitters are given as follows:…”

Improving tools for diagnosing technical condition of ship electric power installations

“…Once we, to determine the value of the optical power recorded at the output of the first secondary core, apply the parameters of real materials, namely [ 29]: The nature of the dependence indicates that the refractive coefficients increase with increasing radial compression, respectively, the number of modes, the relative difference between the refractive indices and the intermodal dispersion decrease.…”

Renewable Carbon Materials as Electrodes for High-Performance Supercapacitors: From Marine Biowaste to High Specific Surface Area Porous Biocarbons

“…Due to their interesting morphological characteristics, higher capacitance can be achieved using electrodes based on porous carbon materials. Nowadays, the approaches to synthesizing AC give the possibility to produce materials with specific surface areas up to 3000–4000 m 2 g –1 . − Graphene oxide (GO), , reduced graphene oxide (rGO), and carbon nanotubes (CNTs), as well as their hybrids, have shown great potential in energy storage applications due to their unique physical and chemical properties. These carbon materials present a high surface area and excellent electrical conductivity, which make them ideal materials for supercapacitors and batteries.…”