Tailoring of the carbon nanowall microstructure by sharp variation of plasma radical composition.

In this paper we propose a new and simple method to tune the carbon nanowall microstructure by sharp variation of CH4/H2 plasma conditions. Using theoretical calculations we demonstrated that the sharp variation of gas pressure and discharge current leads to significant variation of plasma radical composition. In some cases such perturbation creates the necessary conditions for the nucleation of smaller secondary nanowalls on the surface of primary ones.

Extended temperature-accelerated dynamics: enabling long-time full-scale modeling of large rare-event systems.

A new method, the Extended Temperature-Accelerated Dynamics (XTAD), is introduced for modeling long-timescale evolution of large rare-event systems. The method is based on the Temperature-Accelerated Dynamics approach [M. Sørensen and A. Voter, J. Chem. Phys. 112, 9599 (2000)], but uses full-scale parallel molecular dynamics simulations to probe a potential energy surface of an entire system, combined with the adaptive on-the-fly system decomposition for analyzing the energetics of rare events. The method removes limitations on a feasible system size and enables to handle simultaneous diffusion events, including both large-scale concerted and local transitions. Due to the intrinsically parallel algorithm, XTAD not only allows studies of various diffusion mechanisms in solid state physics, but also opens the avenue for atomistic simulations of a range of technologically relevant processes in material science, such as thin film growth on nano- and microstructured surfaces.

Thermal and Electrical Properties of Additively Manufactured Polymer-Boron Nitride Composite.

The efficiency of electronic microchip-based devices increases with advancements in technology, while their size decreases. This miniaturization leads to significant overheating of various electronic components, such as power transistors, processors, and power diodes, leading to a reduction in their lifespan and reliability. To address this issue, researchers are exploring the use of materials that offer efficient heat dissipation. One promising material is a polymer-boron nitride composite. This paper focuses on 3D printing using digital light processing of a model of a composite radiator with different boron nitride fillings. The measured absolute values of the thermal conductivity of such a composite in the temperature range of 3-300 K strongly depend on the concentration of boron nitride. Filling the photopolymer with boron nitride leads to a change in the behavior of the volt-current curves, which may be associated with the occurrence of percolation currents during the deposition of boron nitride. The ab initio calculations show the behavior and spatial orientation of BN flakes under the influence of an external electric field at the atomic level. These results demonstrate the potential use of photopolymer-based composite materials filled with boron nitride, which are manufactured using additive techniques, in modern electronics.

N-Doped Carbon NanoWalls for Power Sources.

Cycling stability and specific capacitance are the most critical features of energy sources. Nitrogen incorporation in crystalline carbon lattice allows to increase the capacitance without increasing the mass of electrodes. Despite the fact that many studies demonstrate the increase in the capacitance of energy sources after nitrogen incorporation, the mechanism capacitance increase is still unclear. Herein, we demonstrate the simple approach of plasma treatment of carbon structures, which leads to incorporation of 3 at.% nitrogen into Carbon NanoWalls. These structures have huge specific surface area and can be used for supercapacitor fabrication. After plasma treatment, the specific capacitance of Carbon NanoWalls increased and reached 600 F g-1. Moreover, we made a novel DFT simulation which explains the mechanism of nitrogen incorporation into the carbon lattice. This work paves the way to develop flexible thin film supercapacitors based on carbon nanowalls.

Publisher Correction: Carbon nanowalls as a platform for biological SERS studies.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

Carbon nanowalls as a platform for biological SERS studies.

Herein we report about developing new type of Surface Enhanced Raman Scattering (SERS) substrates based on Au-decorated carbon nanowalls. The designed substrates possess high specific surface area and high sensitivity. Chemical stability of Au perfectly blends with electrical properties and high value of specific surface area of carbon nanowalls. Created structures were applied to detect signals of a typical molecule used for SERS substrates testing, rhodamine 6G, which exhibits electronic absorption in the visible area of spectrum, and biomacromolecules such as tryptophan, guanine, bovine serum albumin and keratin hydrolysates, whose electronic absorption is in the ultraviolet region of spectrum and lies far from the Au plasmonic resonance. The obtained signals for these compounds suggest that the developed substrate is a prominent platform for the detection of biological macromolecules. The properties of the substrate, including its morphology and Au film thickness, as well as the analyte deposition method, were optimized to achieve the optimum Raman signal enhancement. Electric field distribution in the designed structures was calculated to describe the observed dependence of SERS activity on the substrate morphology.

Controllable Laser Reduction of Graphene Oxide Films for Photoelectronic Applications.

This article presents a new simple method of creating light-absorbing carbon material for optical devices such as bolometers. A simple method of laser microstructuring of graphene oxide is used in order to create such material. The absorption values of more than 98% in the visible and more than 90% in the infrared range are achieved. Moreover thermal properties of the films, such as temperature dependence and the thermal response of the samples, are studied. The change in resistance with temperature is 13 Ohm K-1, temperature coefficient of resistance (TCR) is 0.3% K-1, and the sensitivity is 0.17 V W-1 at 300 K. Thermal conductivity is rather high at ∼104 W m-1 K-1 at 300 K. The designed bolometer operates at room temperature using incandescent lamp as a light source. This technique suggests a new inexpensive way to create a selective absorption coating and/or active layer for optical devices. Developed GO and rGO films have a large surface area and high conductivity. These properties make carbon coatings a perfect candidate for creating a new type of optoelectronic devices (gas sensors, detectors of biological objects, etc.).