TY - JOUR

T1 - Engineering of graphene flakes in the process of synthesis in DC plasma jets

AU - Antonova, Irina V.

AU - Shavelkina, Marina B.

AU - Ivanov, Artem I.

AU - Nebogatikova, Nadezhda A.

AU - Soots, Regina A.

AU - Volodin, Vladimir A.

N1 - Funding Information: A. I. V. acknowledges the financial support of the Russian Science Foundation (Project identifier: 22-19-00191, TEM, IR, Raman and electric measurement). Also A. I. V. (AFM measurements) and S. M. B. (material creation) acknowledges the financial support of the Ministry of Science and Higher Education of the Russian Federation (State Assignments No. 075-01056-22-00 and No. 121-05260-00-74-4, project FWGW-2022-0009). The Raman and IR spectra were registered using the equipment of the Centre of collective usage «VTAN» in the ATRC Department of NSU. Publisher Copyright: © 2022 The Royal Society of Chemistry.

PY - 2022/11/10

Y1 - 2022/11/10

N2 - During the pyrolysis of hydrocarbons in helium plasma jets in a plasma-chemical reactor, graphene flakes of a different structure and resistance were obtained. The presence of hydrogen in these structures was established by physicochemical methods, and its content depends on the pressure in the plasma-chemical reactor and the composition of a plasma-forming system. In addition to hydrogen, a relatively low concentration of oxygen atoms is present in the graphene flakes. Hydrogen is involved in the graphene nucleation, whereas oxygen is absorbed on graphene flakes from the air at low temperatures. It was found that a pressure increase in the reactor (up to 710 Torr) leads to the formation of flakes with a low resistivity (0.12-0.20 kOhm sq−1) and low defect density. In the case of synthesis at a low pressure (350-500 Torr), the resistance of graphene flakes is increased by three orders of magnitude (100-400 kOhm sq−1) with a more complicated defect structure and built-in hydrogen. Moreover, hydrogen is difficult to remove from these flakes, and annealing at relatively high temperatures (up to 300 °C) leads to a weak decrease in the resistance due to flake deformation. Additionally, the functionalization of the graphene flakes synthesized at a low pressure with fluorine atoms is suppressed due to their structural features. In general, the selection of growth parameters (gas pressure in a camera, flow rate and content of impurity atoms) allows one to control the defects in graphene, and its structure and conductivity.

AB - During the pyrolysis of hydrocarbons in helium plasma jets in a plasma-chemical reactor, graphene flakes of a different structure and resistance were obtained. The presence of hydrogen in these structures was established by physicochemical methods, and its content depends on the pressure in the plasma-chemical reactor and the composition of a plasma-forming system. In addition to hydrogen, a relatively low concentration of oxygen atoms is present in the graphene flakes. Hydrogen is involved in the graphene nucleation, whereas oxygen is absorbed on graphene flakes from the air at low temperatures. It was found that a pressure increase in the reactor (up to 710 Torr) leads to the formation of flakes with a low resistivity (0.12-0.20 kOhm sq−1) and low defect density. In the case of synthesis at a low pressure (350-500 Torr), the resistance of graphene flakes is increased by three orders of magnitude (100-400 kOhm sq−1) with a more complicated defect structure and built-in hydrogen. Moreover, hydrogen is difficult to remove from these flakes, and annealing at relatively high temperatures (up to 300 °C) leads to a weak decrease in the resistance due to flake deformation. Additionally, the functionalization of the graphene flakes synthesized at a low pressure with fluorine atoms is suppressed due to their structural features. In general, the selection of growth parameters (gas pressure in a camera, flow rate and content of impurity atoms) allows one to control the defects in graphene, and its structure and conductivity.

UR - http://www.scopus.com/inward/record.url?scp=85142424810&partnerID=8YFLogxK

U2 - 10.1039/d2cp04280k

DO - 10.1039/d2cp04280k

M3 - Article

C2 - 36382495

AN - SCOPUS:85142424810

VL - 24

SP - 28232

EP - 28241

JO - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

SN - 1463-9076

IS - 46

ER -