Theoretical analysis of the stabilization of graphene nanosheets by means of strongly polarized pyrene derivatives

Silva, Nadeesha J.; Borges, Itamar; Tone, Patrick A.; Green, Micah J.; Lischka, Hans; Aquino, Adélia J. A.

doi:10.1016/j.chemphys.2019.110468

Cited by 6 publications

(6 citation statements)

References 55 publications

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“…The sum over atoms in the center is much larger with 0.56 e (sum over atoms C1–C6). Edge polarization effects of the charge density are also observed. , The sum over all edge atoms (C25–C54 and H58–H74) amounts to 0.098 e . It remains practically unchanged between the pristine circumcoronene and the singly and doubly hydrogen chemisorbed compounds.…”

Section: Resultsmentioning

confidence: 96%

“…Edge polarization effects of the charge density are also observed. 43,62 The sum over all edge atoms (C25−C54 and H58−H74) amounts to 0.098 e. It remains practically unchanged between the pristine circumcoronene and the singly and doubly hydrogen chemisorbed compounds. The central CH bond is strongly polarized with a charge of −0.30 e on carbon and +0.30 e on hydrogen.…”

Section: Resultsmentioning

confidence: 99%

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Exploration of Graphene Defect Reactivity toward a Hydrogen Radical Utilizing a Preactivated Circumcoronene Model

2021

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A preexisting chemisorbed defect is well-known to increase the reactivity of graphene which is normally chemically inert. Specifically, the presence of chemisorbed hydrogen atoms forming an sp3-hybridized C–H bond is known to increase the reactivity of neighboring carbon atoms toward additional hydrogenation with wide-ranging applications from materials science to astrochemistry. In this work, static DFT and DFT-based direct dynamics simulations are used to characterize the reactivity of a graphene sheet around an existing C–H bond defect. The spin density landscape shows how to guide subsequent H atom additions, always bonding most strongly to the carbon atom with greatest spin density. Molecular dynamics of an impinging H atom under thermal conditions with defect graphene was used to determine the statistics of probable reactions. The most frequent outcome is inelastic scattering (48%) and then Eley–Rideal (ER) abstraction of the chemisorbed H atom as vibrationally hot H2 (40%), while the least likely, but probably most interesting, result is formation of a novel C–H bond (12%). The C–H bonds always form in the β sublattice. The carbon atom in the para position shows to be most reactive toward the incoming H atom, followed by the ortho carbon, in agreement with the spin density computed in the static calculations. Globally, the graphene energy surface is repulsive, but the defects create local channels into this energy surface through which reactants can move locally through and react with the activated surface without a barrier.

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Exploration of Graphene Defect Reactivity toward a Hydrogen Radical Utilizing a Preactivated Circumcoronene Model

2021

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“…This suggests that the presence of the pyrenyl galactosides enhances the aqueous stability of the nanowires. 13 Increasing concentrations of GNR-PEO -based nanowires added to deionized water solutions of Gal-pyr gradually quenched the fluorescence of the latter (Fig. 2d), which is probably due to the Förster resonance energy transfer from pyrene to the GNR-PEO after self-assembly.…”

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confidence: 94%

Targeted photothermal release of antibiotics by a graphene nanoribbon-based supramolecular glycomaterial

et al. 2023

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“…[1][2][3][4][5][6][7] It is used in several important applications; for instance, as a dispersant to avoid the re-association of graphene sheets in the production of single (few) layer graphene sheets. 8 Pyrene and pyrenyl derivatives can behave as intramolecular charge transfer (ICT) molecules with applications in organic thin-films transistors and different types of organic electronic devices [9][10][11][12][13][14] due to the selective functionalization ability of the pyrene core. 1,15 Pyrene was first employed as a π-conjugated bridge in a donor (D)-pyrene (P (bridge))-acceptor (A) (DPA) organic dye for use as sensitizer in dyesensitized solar cells (DSSCs), with diarylamine or indoline used as a donor, and cyanoacrylic acid as an electron acceptor 16 (Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

“…It has a rich and unusual photophysical behavior showing anti‐Kasha fluorescence from S 2 and even from higher excited states 1–7 . It is used in several important applications; for instance, as a dispersant to avoid the re‐association of graphene sheets in the production of single (few) layer graphene sheets 8 . Pyrene and pyrenyl derivatives can behave as intramolecular charge transfer (ICT) molecules with applications in organic thin‐films transistors and different types of organic electronic devices 9–14 due to the selective functionalization ability of the pyrene core 1,15 .…”

Section: Introductionmentioning

confidence: 99%

A comprehensive analysis of charge transfer effects on donor‐pyrene (bridge)‐acceptor systems using different substituents

Borges,

Guimarães,

Monteiro‐de‐Castro

et al. 2023

J Comput Chem

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The alternant polycyclic aromatic hydrocarbon pyrene has photophysical properties that can be tuned with different donor and acceptor substituents. Recently, a D (donor)‐Pyrene (bridge)‐A (acceptor) system, DPA, with the electron donor N,N‐dimethylaniline (DMA), and the electron acceptor trifluoromethylphenyl (TFM), was investigated by means of time‐resolved spectroscopic measurements (J. Phys. Chem. Lett. 2021, 12, 2226–2231). DPA shows great promise for potential applications in organic electronic devices. In this work, we used the ab initio second‐order algebraic diagrammatic construction method ADC(2) to investigate the excited‐state properties of a series of analogous DPA systems, including the originally synthesized DPAs. The additionally investigated substituents were amino, fluorine, and methoxy as donors and nitrile and nitro groups as acceptors. The focus of this work was on characterizing the lowest excited singlet states regarding charge transfer (CT) and local excitation (LE) characters. For the DMA‐pyrene‐TFM system, the ADC(2) calculations show two initial electronic states relevant for interpreting the photodynamics. The bright S1 state is locally excited within the pyrene moiety, and an S2 state is localized ~0.5 eV above S1 and characterized as a donor to pyrene CT state. HOMO and LUMO energies were employed to assess the efficiency of the DPA compounds for organic photovoltaics (OPVs). HOMO‐LUMO and optical gaps were used to estimate power conversion and light‐harvesting efficiencies for practical applications in organic solar cells. Considering the systems using smaller D/A substituents, compounds with the strong acceptor NO2 substituent group show enhanced CT and promising properties for use in OPVs. Some of the other compounds with small substituents are also found to be competitive in this regard.

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Theoretical analysis of the stabilization of graphene nanosheets by means of strongly polarized pyrene derivatives

Cited by 6 publications

References 55 publications

Exploration of Graphene Defect Reactivity toward a Hydrogen Radical Utilizing a Preactivated Circumcoronene Model

Exploration of Graphene Defect Reactivity toward a Hydrogen Radical Utilizing a Preactivated Circumcoronene Model

Targeted photothermal release of antibiotics by a graphene nanoribbon-based supramolecular glycomaterial

A comprehensive analysis of charge transfer effects on donor‐pyrene (bridge)‐acceptor systems using different substituents

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