Highly stable two-dimensional graphene oxide: Electronic properties of its periodic structure and optical properties of its nanostructures

Zhang, Qin; Zhang, Hong; Cheng, Xinlu

doi:10.1088/1674-1056/27/2/027301

Cited by 11 publications

(9 citation statements)

References 35 publications

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“…The oxidation of graphene increases the material’s optical bandgap energy E g . Consequently, one expects the reduction process to decrease the measured bandgap energy since rGO is more graphene-like than GO. , Figure presents the Tauc plot, which is used to estimate the bandgap values of our samples based on optical reflection experiments and the following expression: where α is the linear absorption coefficient, A is a constant measuring the disorder of the material, , h is Plank’s constant, ν is the incident photon’s frequency, and n is equal to 1/2 since GO and rGO are considered direct bandgap materials. , From the experimental measurements, we extract E g = 3.93 eV for GO and lower values of 3.01 and 3.14 eV for rGO V and rGO L , respectively. These smaller bandgap energies are consistent with a material structurally closer to graphene.…”

Section: Resultsmentioning

confidence: 99%

A Comparative Investigation of Chemically Reduced Graphene Oxide Thin Films Deposited via Spray Pyrolysis

2022

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We present a comparative investigation between thin films of graphene oxide (GO) and chemically reduced graphene oxide (rGO) deposited onto glass substrates via spray pyrolysis. Two reduction techniques are investigated: (1) the exposition of a sprayed layer of GO to vapors of hydrazine hydrate to produce rGO V and (2) the addition of liquid hydrazine hydrate to a suspended GO solution, which is then sprayed onto a substrate to produce rGO L . Three different spectroscopy techniques, Raman, Fourier transform infrared, and UV–Vis–NIR, show that the two reduced samples have less lattice disorder in comparison to GO, with rGO L having the highest degree of reduction. Interestingly, topography characterization by atomic force microscopy reveals a morphological change occurring during the exposure to hydrazine hydrate vapors, resulting in a thickness of 110 nm for the rGO V film, which is a factor of 16 larger than rGO L and GO. Finally, I – V measurements show a significant decrease of the GO’s resistivity after the reduction process, where rGO L features a resistivity 90 times lower than rGO V , confirming that rGO L has the highest degree of reduction. Our results indicate that the reduction process for rGO V is susceptible to introducing intercalated water molecules in the material while the fabrication technique for rGO L is a suitable route to obtain a material with minimal lattice disorder and properties approaching those of graphene.

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Section: Resultsmentioning

confidence: 99%

A Comparative Investigation of Chemically Reduced Graphene Oxide Thin Films Deposited via Spray Pyrolysis

2022

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“…If the phonon dispersion of one material has no negative frequency, then it usually means that it is kinetically stable. [15] For cumulene, there are some parts showing negative frequencies with the lowest value down to −3.817 THz, which indicates that cumulene is kinetically unstable and therefore it could be unstable at room temperature and normal pressure. Some thermodynamic quantities obtained by GGA-PW91, including the enthalpy (which is just the summation of the Gibbs free energy and a term given by the product of temperature and entropy, T * entropy), Gibbs free energy, entropy, and the heat capacity of the cumulene, are shown in Fig.…”

Section: Phonon Propertiesmentioning

confidence: 96%

“…14, the modes are mixed and there is no phonon band gap. If the phonon dispersion of one material has no negative frequency, it illustrates that it is kinetically stable [15] . For cumulene, there are some parts with negative frequencies with the lowest value down to -3.817THz, which indicates that cumulene is kinetically unstable and it could be unstable at room temperature and normal pressure.…”

Section: Phonon Propertiesmentioning

confidence: 99%

First-principles study on the mechanics, optical, and phonon properties of carbon chains

Meng

et al. 2018

Chinese Phys. B

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Besides graphite, diamond, graphene, carbon nanotubes, and fullerenes etc., there is another allotrope of carbon: carbyne, existing in the form of a onedimensional chain of carbon atoms. It has been theoretically predicted that carbyne would be stronger, stiffer and more exotic than other materials that have been synthesized before. In this article, the two kinds of carbyne, i.e., cumulene and polyyne, are investigated by the first principles, where the mechanical properties, electronic structure, optical and phonon properties of the two carbynes are calculated.The results on the crystal binding energy and the formation energy show that polyyne is more stable and harder than cumulene, and both are difficult to be synthesized from diamond or graphite. The tensile stiffness, bond stiffness and Young's modulus of cumulene are 94.669 eV/Å, 90.334GPa and 60.62GPa, respectively; while the corresponding values of polyyne are 94.939eV/Å, 101.42GPa and 60.06GPa, respectively. The supercell calculation shows that carbyne is the most stable at N=5, where N is the supercell number. It indicates that the carbon chain with 10 atoms is the most stable. The calculation on the electronic band structure shows that cumulene is conductor, while polyyne is semiconductor with a band gap as 0.37eV. The dielectric function of carbynes varies in different direction, consistent with the one dimensional nature of the carbon chains. In the phonon dispersion of cumulene there are imaginary frequencies with the lowest value down to -3.817THz, which indicates that cumulene could be unstable at room temperature and normal pressure.

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“…Among inorganic nanomaterials, GO has a typical quasi-two-dimensional structure [17] and its layer contains many oxygen-containing groups. Because of its high specific surface energy, good hydrophilicity and good mechanical properties [18], GO is considered as an ideal polymer nano-based composite fiber additive for polymers. Tiwari et al investigated the effects of different GO loadings on the compatibility, thermomechanical and morphological properties of incompatible PP/polycarbonate polymer blends [19].…”

Section: Introductionmentioning

confidence: 99%

Effect of Compatibilizer on the Interface Bonding of Graphene Oxide/Polypropylene Composite Fibers

et al. 2018

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To improve the interfacial bonding and thermal stability of graphene oxide (GO)/polypropylene (PP) composite fibers, a composite fiber with PP as the matrix, GO as reinforcement and maleic anhydride-grafted PP (PP-g-MAH) as a compatibilizer was prepared by a simple and efficient melt-blending method. The GO content was 0.0–5.0 wt %. According to the Fourier Transform Infrared (FT-IR) spectroscopy results, the interfacial bonding in the PP/MAH/GO composite fibers was improved. The Dynamic Mechanical Analysis (DMA) results show that the addition of GO resulted in better interfacial adhesion and higher storage modulus (E′). The loss modulus (E′′) of the PP/MAH/GO-x composite fibers increased with increasing amount of added GO, whereas the loss factor (tan δ) decreased. GO and PP-g-MAH were analyzed by Thermogravimetric Analysis (TGA). The thermal stability of the composite fibers was improved compared to PP. Differential Scanning Calorimetry (DSC) analysis showed that the addition of PP-g-MAH to the composite fiber improved the interfacial bonding of GO in the PP matrix. Thus, compatibility between the two components was obtained. Based on the Scanning Electron Microscopy (SEM) results, the PP fibers exhibited relative orientation due to the strong crystalline morphology. The rough section, PP/GO blend fiber exhibits a very clear phase separation morphology due to the incompatibility between the two and the compatibility of GO and PP in PP/MAH/GO-3 composite fiber is improved, resulting in the interface between the two has improved.

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Highly stable two-dimensional graphene oxide: Electronic properties of its periodic structure and optical properties of its nanostructures

Cited by 11 publications

References 35 publications

A Comparative Investigation of Chemically Reduced Graphene Oxide Thin Films Deposited via Spray Pyrolysis

A Comparative Investigation of Chemically Reduced Graphene Oxide Thin Films Deposited via Spray Pyrolysis

First-principles study on the mechanics, optical, and phonon properties of carbon chains

Effect of Compatibilizer on the Interface Bonding of Graphene Oxide/Polypropylene Composite Fibers

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