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Structural and Electronic Properties of a New Multilayer Graphene/Graphane Material
Published in Olga E. Glukhova, 2D and 3D Graphene Nanocomposites, 2019
Olga E. Glukhova, Vladislav V. Shunaev, Michael M. Slepchenkov
Graphene demonstrates unique mechanical [1], electronic, and magnetic properties that can be varied by size and chirality [2, 3]. Hydrogenated graphene, also known as graphane, has an energy gap that lies in the range of 3.5–4.5 eV [4–7]. Recently, a lot of attention has been given to hybrid graphene/graphane nanocomposites since their combination can find application in thin, flexible displays, solar panels, and waveguides [8]. Hybrid structures based on graphene and graphane are synthesized from graphite in a medium of hydrogen gas at a pressure of more than 2 GPa and at a temperature of 450–700°C [9]. Another way of forming such structures is laser irradiation of graphene, on the surface of which H2O or NH3 molecules are adsorbed [10]. In the latter case, hydrogenation of graphene is possible on only one side of the sheet.
Low-Stress Transfer of Graphene and Its Tunable Resistance by Remote Plasma Treatments in Hydrogen
Published in James E. Morris, Krzysztof Iniewski, Nanoelectronic Device Applications Handbook, 2017
Waileong Chen, Chia-Hao Tu, Keng-Chih Liang, Chih-Yi Liu, Chuan-Pu Liu, Yonhua Tzeng
As reported in previous research works [14–16], when graphene is fully terminated by hydrogen, the electrically conductive graphene is converted into electrically insulating graphane, which has direct band gaps with Eg = 3.5 eV for the chair form and with Eg = 3.7 eV for the boat form. The calculated graphane C–C bond length of 1.52 Å is similar to the sp3 bond length of 1.53 Å in diamond and is much greater than the 1.42 Å characteristics of sp2 carbon in graphene [17]. So the atomic structure is also different from that of graphene. Graphene has a 2D flat plane structure, whereas graphane has an extended 2D covalently bonded structure [17]. Moreover, what if only one side of the graphene carbon atoms is terminated with hydrogen atoms? It is called graphone, which has been calculated to have an indirect band gap of 0.46 eV. And it is ferromagnetic while graphene and graphane are nonmagnetic [18]. Therefore, it is possible to tune the electronic and magnetic properties of graphene by hydrogenation. The possibility of band gap engineering with hybrid graphane–graphene nanostructures is desirable and promising [19]. To achieve this, a novel handling and transfer process for synthesized graphene is necessary.
Electrochemistry of Porous Carbon-Based Materials
Published in Antonio Doménech-Carbó, Electrochemistry of Porous Materials, 2021
An enormous variety of composites using graphene, GO, and rGO have been investigated for electrocatalysis and sensing. These are accompanied by a variety of functionalization and doping strategies [4–6]. Hydrogenation of graphene leads to graphane, a material with interesting properties [32].
Diamane: design, synthesis, properties, and challenges
Published in Functional Diamond, 2022
Guowen Qin, Lailei Wu, Huiyang Gou
The study of functionalized graphene can be traced back to 2007. A structure was proposed by Sofo et al. [5] with hydrogen saturated surfaces of SLG, in which the carbon atoms becomes sp3 hybridization, and the fully hydrogenated SLG structure was named “graphane.” After that, Elias et al. [4] obtained partially hydrogenated SLG that behaved as an insulator by placing a remarkably conductive graphene sample in hydrogen plasma. Following, the electronic properties of partially hydrogenated SLG were investigated [4,19] and the fully fluorinated SLG [7] were synthesized successfully in experiment. Then in 2009, Chernozatonskii et al. [20] tentatively simulated the C2H structure formed by the adsorption of hydrogen atoms on the BLG of AB (Bernal) stacking and AA (Lonsdaleite) stacking and named them “diamane.” In the past decades, numerous investigations on the properties of diamane were performed and its potential applications were found in the fields of nano-photonics [21,22] and ultrasensitive resonator-based sensors [23]. Recently, it is exciting that the fully fluorinated AB-stacked diamane [24] and pristine diamane with (110) orientation [25] were synthesized successfully in experiments. It should be noted that in previous literatures, different names, such as diamane [20,24–26], diamondol [27], diamondene [28], or diamene [29], was adopted for diamane, due to the diversity of surface functional groups on the diamond film surface. Here, for the convenience of discussion, we call them collectively as diamane.