Structural and vibrational study of graphene oxide via coronene based models: theoretical and experimental results

Mendonça, João Paulo Almeida de; Lima, Alessandro Henrique de; Junqueira, Geórgia M. A.; Quirino, Welber G.; Legnani, Cristiano; Maciel, Indhira O.; Sato, F.

doi:10.1088/2053-1591/3/5/055020

Cited by 18 publications

(8 citation statements)

References 37 publications

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“…DFT-based models of the oxygen–coronene interaction have predicted the formation of epoxy, hydroxyl, and carboxyl functionalities. ,, The adoption of impinging oxygen atoms by the graphitic core of a coronene molecule ends with the formation of epoxy species: the resulting epoxide triangle is strained because the two carbon atoms involved rearrange from a planar sp 2 - to a distorted sp 3 -hybridized geometry resulting in nonideal angles. This elementary step stretches the C–C bond and lowers the total energy of the system by 2.4 eV. , When positioning two oxygen atoms over a carbon hexagon one finds only two stable structures: (1) two epoxy groups bind to opposite hexagon sides or (2) they are separated from each other by one hexagon side.…”

Section: Resultsmentioning

confidence: 99%

Formation of Sublimable Nanographene Oxides by Reacting Coronene Films with Atomic Oxygen

et al. 2018

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We have studied the oxidation of multilayer thin films of coronene (C 24 H 12 ) on graphite under UHV conditions. Coronene films were grown by low-energy cluster ion beam deposition (LECBD, C 24 H 12 + , E kin < 6 eV) and subsequently oxidized by exposing them to a beam of nearthermal atomic oxygen at room temperature. Mass spectra recorded during sublimation of the oxidized coronene films reveal a distribution of emitted species, C 24 H 12 O n (n ≤ 7), which we assign as coronene epoxides. From the fragmentation pattern we infer that primarily rim epoxides are formed, which exhibit a higher stability than core epoxides according to DFT calculations. In addition to epoxides, XPS indicates that other oxidic functional groups, such as ethers, are also formed in smaller relative amounts as nonsublimable species. The overall yield for the thermal desorption of intact coronene oxides can be up to 7% of the deposited coronene, sufficiently high such that this procedure could be useful as a source of monodispersed nanoscale graphene oxides (nano-GOs) for applications in nanotechnology.

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Section: Resultsmentioning

confidence: 99%

Formation of Sublimable Nanographene Oxides by Reacting Coronene Films with Atomic Oxygen

et al. 2018

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“…As mentioned before, the basis of 150 carbon atoms for describing the graphene-like core in all the molecules have been demonstrated as adequate for the study of its vibrational properties. 13 Anyway, the direct interpretation of the vibrational modes seems to be complex. In one hand, this is due to large number of atoms and thus the large number of degrees of freedom involved in the system.…”

Section: Resultsmentioning

confidence: 99%

“…These sizes of the molecules have been demonstrated as adequate for describing graphene or graphene oxide successfully from the vibrational point of view. 13 In the case of the PANI polymer, we considered the emeraldine salt ([C 6 H 4 NH] 2 [C 6 H 4 N] 2 ) n with n = 7, see Figure 1.…”

Section: Methodsmentioning

confidence: 99%

Electronic Structure of Edge-Modified Graphene Quantum Dots Interacting with Polyaniline: Vibrational and Optical Properties

et al. 2017

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There are recent experimental reports on the preparation of edge-modified graphene quantum dots (GQDs) and its loading into conductive polymers for energy applications. Recently, we have studied the influence of the graphene quantum dots (GQDs) addition to polyaniline (PANI) conductive polymer in the electronic transport, finding important modifications in the structural and electrical properties respect to the pristine polymer. In this work, we present a mixed approach, based in firstprinciples molecular dynamics with time-dependent density functional calculations, for the description of the electronic dynamics, particularly for the determination of the optical properties. We found that edge modification of the GQDs favors the PANI/GQDs interaction, promoting very interesting electronic properties. Particularly, when hydroxyl chemical functional groups are present at the edges of the GQD a very good electron−hole separation during the photon excitation is obtained, demonstrating its potential use for optical applications in general and solar cells in particular.

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“…Fourier‐transform infrared (FTIR) and Raman measurements provide more clearer evidence (Figure d,e; Supporting Information, Figures S6, S7), where FTIR analysis shows that the C−H vibrations of NDI (ν (C−H) : 2963 cm −1 ; δ (C−H) : 772 cm −1 ) are red‐shifted to 2956 cm −1 and 763 cm −1 , respectively (suggesting the negatively charged), while the C−H band of Cor. exhibits blue‐shift (Δ ν ≈9 cm −1 , indicating the positive charge) after co‐crystallization . Similarly, the C=C band of cocrystal NCT (Raman spectra) displays a bathochromic shift for NDI unit (Δ ν ≈9 cm −1 ) but a blue‐shift for Cor.…”

Section: Resultsmentioning

confidence: 94%

Rational Control of Charge Transfer Excitons Toward High‐Contrast Reversible Mechanoresponsive Luminescent Switching

Wang

Chen

et al. 2020

Angewandte Chemie

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A practicable strategy to rationally obtain the reversible mechanochromic luminescent (MCL) material with high‐contrast ratio (green versus red) has been established. By introducing a volatile third party (small‐sized solvent molecules) into the lattice of charge transfer (CT) cocrystal of mixed‐stacking 1:1 coronene (Cor.) and napthalenetetracarboxylic diimide (NDI), a noteworthy reconfigurable molecular assembly is ingeniously achieved owing to the loosely packing arrangement as well as weakened intermolecular interactions. Accordingly, the CT excited state, strongly corresponding to the molecular stacking modes, can be intentionally tailored through external stimulus (heating, grinding, or solvent), accompanying distinct changes in photophysical properties. Subsequently, a high‐contrast reversible MCL with highly sensitive and good reproducibility is realized and the underlying mechanism is thoroughly revealed.

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Structural and vibrational study of graphene oxide via coronene based models: theoretical and experimental results

Cited by 18 publications

References 37 publications

Formation of Sublimable Nanographene Oxides by Reacting Coronene Films with Atomic Oxygen

Formation of Sublimable Nanographene Oxides by Reacting Coronene Films with Atomic Oxygen

Electronic Structure of Edge-Modified Graphene Quantum Dots Interacting with Polyaniline: Vibrational and Optical Properties

Rational Control of Charge Transfer Excitons Toward High‐Contrast Reversible Mechanoresponsive Luminescent Switching

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