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Photoluminescence and Photocatalytic Properties of MWNTs Decorated with Fe-Doped ZnO Nanoparticles. MATERIALS (BASEL, SWITZERLAND) 2023; 16:2858. [PMID: 37049152 PMCID: PMC10095740 DOI: 10.3390/ma16072858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 03/30/2023] [Accepted: 03/31/2023] [Indexed: 06/19/2023]
Abstract
The present work reports the photoluminescence (PL) and photocatalytic properties of multi-walled carbon nanotubes (MWCNTs) decorated with Fe-doped ZnO nanoparticles. MWCNT:ZnO-Fe nanocomposite samples with weight ratios of 1:3, 1:5 and 1:10 were prepared using a facile synthesis method. The obtained crystalline phases were evidenced by X-ray diffraction (XRD). X-ray Photoelectron spectroscopy (XPS) revealed the presence of both 2+ and 3+ valence states of Fe ions in a ratio of approximately 0.5. The electron paramagnetic resonance EPR spectroscopy sustained the presence of Fe3+ ions in the ZnO lattice and evidenced oxygen vacancies. Transmission electron microscopy (TEM) images showed the attachment and distribution of Fe-doped ZnO nanoparticles along the nanotubes with a star-like shape. All of the samples exhibited absorption in the UV region, and the absorption edge was shifted toward a higher wavelength after the addition of MWCNT component. The photoluminescence emission spectra showed peaks in the UV and visible region. Visible emissions are a result of the presence of defects or impurity states in the material. All of the samples showed photocatalytic activity against the Rhodamine B (RhB) synthetic solution under UV irradiation. The best performance was obtained using the MWCNT:ZnO-Fe(1:5) nanocomposite samples, which exhibited a 96% degradation efficiency. The mechanism of photocatalytic activity was explained based on the reactive oxygen species generated by the nanocomposites under UV irradiation in correlation with the structural and optical information obtained in this study.
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On-Surface Synthesis of Variable Bandgap Nanoporous Graphene. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2102246. [PMID: 34535956 DOI: 10.1002/smll.202102246] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 07/26/2021] [Indexed: 06/13/2023]
Abstract
Tuning the bandgap of nanoporous graphene is desirable for applications such as the charge transport layer in organic-hybrid devices. The holy grail in the field is the ability to synthesize 2D nanoporous graphene with variable pore sizes, and hence tunable band gaps. Herein, the on-surface synthesis of nanoporous graphene with variable bandgaps is demonstrated. Two types of nanoporous graphene are synthesized via hierarchical CC coupling, and are verified by low-temperature scanning tunneling microscopy and non-contact atomic force microscopy. Nanoporous graphene-1 is non-planar, and nanoporous graphene-2 is a single-atom thick planar sheet. Scanning tunneling spectroscopy measurements reveal that nanoporous graphene-2 has a bandgap of 3.8 eV, while nanoporous graphene-1 has a larger bandgap of 5.0 eV. Corroborated by first-principles calculations, it is proposed that the large bandgap opening is governed by the confinement of π-electrons induced by pore generation and the non-planar structure. The finding shows that by introducing nanopores or a twisted structure, semi metallic graphene is converted into semiconducting nanoporous graphene-2 or insulating wide-bandgap nanoporous graphene-1.
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Abstract
Using a simple but powerful geometrical/topological notion of aromaticity based on the shell model (Zdetsis, A. D. J. Phys. Chem. C 2018, 122, 17526-17536) and the bipartite topology, we uncover, on top of the geometrical virtual "equivalence" of the fundamental Hückel and Clar rules of aromaticity, the significance of empty peripheral rings, which are shown to be linked to zigzag edge states. Such empty rings can be thought of as "inversion symmetry incompatible". Thus, the elimination of these rings under the existing symmetry constrains preserves the aromaticity pattern and leads to a substantial improvement in the stability and/or sublattice imbalance, resulting in larger electronic band gaps and a lack of zigzag edge/end states. Using these ideas, we can illustrate that trigonal D3h-symmetric nanographens cannot be graphene-like because they are either armchair without Dirac points or zigzag-bonded (triangulenes) topologically frustrated with high spin states. This is also true for hexagonal heteroatomic BN or SiC structures, contrary to homoatomic silicene, germanene, and so forth. Existing paradigms are highly suggestive that such an elimination process could occur naturally.
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How Do Defects in Carbon Nanostructures Regulate the Photoinduced Electron Transfer Processes? The Case of Phenine Nanotubes. Chemphyschem 2021; 22:1178-1186. [PMID: 33871156 PMCID: PMC8252612 DOI: 10.1002/cphc.202100285] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Indexed: 12/22/2022]
Abstract
Photoinduced electron transfer is studied in a series of inclusion complexes of structurally modified phenine nanotubes (pNT) with C70 using the TD-DFT method. Analysis of electronic properties of the complexes shows that the electron transfer is infeasible in pNT_4d⊃C70 built on the tetrameric array of [6]cyclo-meta-phenylene ([6]CMP) units. However, replacing one or more [6]CMP units with a coronene moiety enables electron transfer from pNT to C70 . The generation of the charge separated states from the lowest locally excited states occurs on a sub-nanosecond time scale. Depending on the number of the [6]CMP units, the charge recombination rate varies from 1.8 ⋅ 107 to 3.1 ⋅ 102 s-1 , i. e., five orders of magnitude.
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Covalent Functionalization of Single-Walled Carbon Nanotubes by the Bingel Reaction for Building Charge-Transfer Complexes. J Org Chem 2020; 85:11721-11731. [PMID: 32820915 DOI: 10.1021/acs.joc.0c01384] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Functionalization of nanotubes with donor and acceptor partners by the Bingel reaction leads to the formation of charge-transfer dyads, which can operate in organic photovoltaic devices. In this work, we theoretically examine the mechanism of the Bingel reaction for the (6,5)-chiral, (5,5)-armchair, and (9,0)-zigzag single-walled carbon nanotubes (SWCNTs), and demonstrate that the reaction is regioselective and takes place at the perpendicular position of (6,5)- and (5,5)-SWCNTs, and the oblique position of (9,0)-SWCNT. Further, we design computationally the donor-acceptor complexes based on (6,5)-SWCNT coupled with partners of different electronic nature. Analysis of their excited states reveals that efficient photoinduced charge transfer can be achieved in the complexes with π-extended analogue of tetrathiafulvalene (exTTF), zinc tetraphenylporphyrin (ZnTPP), and tetracyanoanthraquinodimethane (TCAQ). The solvent can significantly affect the population of the charge-separated states. Our calculations show that electron transfer (ET) occurs in the normal Marcus regime on a sub-nanosecond time scale in the complexes with exTTF and ZnTPP, and in the inverted Marcus regime on a picosecond time scale in the case of the TCAQ derivative. The ET rate is found to be not very sensitive to the degree of functionalization of the nanotube.
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Abstract
Carbon nanotubes (CNTs) promise to advance a number of real-world technologies. Of these applications, they are particularly attractive for uses in chemical sensors for environmental and health monitoring. However, chemical sensors based on CNTs are often lacking in selectivity, and the elucidation of their sensing mechanisms remains challenging. This review is a comprehensive description of the parameters that give rise to the sensing capabilities of CNT-based sensors and the application of CNT-based devices in chemical sensing. This review begins with the discussion of the sensing mechanisms in CNT-based devices, the chemical methods of CNT functionalization, architectures of sensors, performance parameters, and theoretical models used to describe CNT sensors. It then discusses the expansive applications of CNT-based sensors to multiple areas including environmental monitoring, food and agriculture applications, biological sensors, and national security. The discussion of each analyte focuses on the strategies used to impart selectivity and the molecular interactions between the selector and the analyte. Finally, the review concludes with a brief outlook over future developments in the field of chemical sensors and their prospects for commercialization.
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Regioselectivity of the Pauson-Khand reaction in single-walled carbon nanotubes. NANOSCALE 2018; 10:15078-15089. [PMID: 30059118 DOI: 10.1039/c8nr03480j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Chemical functionalization of nanotubes, in which their properties can be combined with those of other classes of materials, is fundamental to improve the physicochemical properties of nanotubes for potential technological applications. In this work, we theoretically and experimentally examine the Pauson-Khand reaction (PKR) on zig-zag, armchair, and chiral single-walled carbon nanotubes (SWCNTs). Our benchmarked density functional theory (DFT) calculations show that an alternative pathway to the widely accepted Magnus reaction pathway has significantly lower energy barriers, thus suggesting the use of this alternative pathway to predict whether a PKR on SWCNTs is favored or hampered. Accessible energy barriers of up to 16 kcal mol-1 are estimated and our results suggest that semiconducting SWCNTs react faster than metallic ones, although both types can be functionalized. Guided by our theoretical predictions, cyclopentenones are successfully attached to SWCNTs by heating and are, subsequently, characterized in the laboratory.
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Combined molecular and periodic DFT analysis of the adsorption of co macrocycles on graphene. J Comput Chem 2018; 39:130-138. [PMID: 29094373 DOI: 10.1002/jcc.25093] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 09/27/2017] [Accepted: 10/16/2017] [Indexed: 01/09/2023]
Abstract
The molecular doping of graphene with π-stacked conjugated molecules has been widely studied during the last 10 years, both experimentally or using first-principle calculations, mainly with strongly acceptor or donor molecules. Macrocyclic metal complexes have been far less studied and their behavior on graphene is less clear-cut. The present density functional theory study of cobalt porphyrin and phthalocyanine adsorbed on monolayer or bilayer graphene allows to compare the outcomes of two models, either a finite-sized flake of graphene or an infinite 2D material using periodic calculations. The electronic structures yielded by both models are compared, with a focus on the density of states around the Fermi level. Apart from the crucial choice of calculation conditions, this investigation also shows that unlike strongly donating or accepting organic dopants, these macrocycles do not induce a significant doping of the graphene sheet and that a finite size model of graphene flake may be confidently used for most modeling purposes. © 2017 Wiley Periodicals, Inc.
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Modeling adsorbate-induced property changes of carbon nanotubes. J Comput Chem 2017; 38:861-868. [PMID: 28245063 DOI: 10.1002/jcc.24760] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 12/30/2016] [Accepted: 01/09/2017] [Indexed: 11/05/2022]
Abstract
Because of their potential for chemical functionalization, carbon nanotubes (CNTs) are promising candidates for the development of devices such as nanoscale sensors or transistors with novel gating mechanisms. However, the mechanisms underlying the property changes due to functionalization of CNTs still remain subject to debate. Our goal is to reliably model one possible mechanism for such chemical gating: adsorption directly on the nanotubes. Within a Kohn-Sham density functional theory framework, such systems would ideally be described using periodic boundary conditions. Truncating the tube and saturating the edges in practice often offers a broader selection of approximate exchange-correlation functionals and analysis methods. By comparing the two approaches systematically for NH3 and NO2 adsorbates on semiconducting and metallic CNTs, we find that while structural properties are less sensitive to the details of the model, local properties of the adsorbate may be as sensitive to truncation as they are to the choice of exchange-correlation functional, and are similarly challenging to compute as adsorption energies. This suggests that these adsorbate effects are nonlocal. © 2017 Wiley Periodicals, Inc.
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Reactivity of Single-Walled Carbon Nanotubes in the Diels-Alder Cycloaddition Reaction: Distortion-Interaction Analysis along the Reaction Pathway. Chemistry 2016; 22:12819-24. [PMID: 27465519 DOI: 10.1002/chem.201601799] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Indexed: 11/06/2022]
Abstract
Diels-Alder cycloaddition is one of the most powerful tools for the functionalization of single-walled carbon nanotubes (SWCNTs). Density functional theory at the B3-LYP level of theory has been used to investigate the reactivity of different-diameter SWCNTs (4-9,5) in Diels-Alder reactions with 1,3-butadiene; the reactivity was found to decrease with increasing SWCNT diameter. Distortion/interaction analysis along the whole reaction pathway was found to be a better way to explore the reactivity of this type of reaction. The difference in interaction energy along the reaction pathway is larger than that of the corresponding distortion energy. However, the distortion energy plots for these reactions show the same trend. Therefore, the formation of the transition state can be determined from the interaction energy. A lower interaction energy leads to an earlier transition state, which indicates a lower activation energy. The computational results also indicate that the original distortion of the SWCNTs leads to an increase in the reactivity of the SWCNTs.
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A self-assembled lysinated perylene diimide film as a multifunctional material for neural interfacing. J Mater Chem B 2016; 4:2921-2932. [PMID: 32262970 DOI: 10.1039/c5tb02299a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We report the design, synthesis and structure-property investigation of a new perylene diimide material (PDI-Lys) bearing lysine end substituents. Water processed films of PDI-Lys were prepared and their self-assembly, morphology and electrical properties in both inert and air environments were theoretically and experimentally investigated. With the aim of evaluating the potential of PDI-Lys as a biocompatible and functional neural interface for organic bioelectronic applications, its electrochemical impedance as well as the adhesion and viability properties of primary neurons on the PDI-Lys films were studied. By combining theoretical calculations and electrical measurements we show that due to conversion between neutral and zwitterionic anions, the PDI-Lys film conductivity increased significantly upon passing from air to an inert atmosphere, reaching a maximum value of 6.3 S m-1. We also show that the PDI-Lys film allows neural cell adhesion and neuron differentiation and decreases up to 5 times the electrode/solution impedance in comparison to a naked gold electrode. The present study introduces an innovative, water processable conductive film usable in organic electronics and as a putative neural interface.
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Abstract
A theoretical study on the strain energy of carbon nanobelts, i.e. the belt-shaped molecules representing the sidewall structures of carbon nanotubes, is reported. The strain energy of carbon nanobelts with chiral indices (n,n), (n,0), and (n,m) was determined without considering hypothetical homodesmotic reactions. The calculated difference between the strain energy of carbon nanobelts and their possible precursors is expected to be of great utility for future synthetic purposes.
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An Analysis of the Carbon Number Dependence of Electronic Structures in Carbon Nanotubes by Means of Reduced HOMO-LUMO Gap. JOURNAL OF COMPUTER CHEMISTRY-JAPAN 2016. [DOI: 10.2477/jccj.2015-0071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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The Clar Structure in Inorganic BN Analogues of Polybenzenoid Hydrocarbons: Does it Exist or Not? Chemphyschem 2015; 16:3806-13. [PMID: 26467786 DOI: 10.1002/cphc.201500811] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Indexed: 11/11/2022]
Abstract
The Clar structure of polybenzenoid hydrocarbons (PBHs) have attracted considerable interest of both theoretical and experimental chemists since it was proposed in the 1950s. However, it remains unclear whether the Clar structure could exist in inorganic PBHs, the boron nitride (BN) analogues where the alternate boron and nitrogen atoms are used to replace the carbon atoms of PBHs. Here, we carry out thorough density functional theory (DFT) calculations to probe the possibility of Clar structures in BN analogues of PBHs. A strong correlation (r(2) =0.975) between the ring number (n=3-10) of BN analogues of [n]acenes and energy differences between the most and least stable isomers is identified, suggesting the existence of Clar structures in inorganic PBHs. In addition, the slightly weaker correlations in comparison to that (r(2) =0.989) of the organic PBHs is rationalized by the reduced aromaticity, which is revealed by two aromatic indices: ELFπ and SCI.
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Periodically Modulated Size-Dependent Elastic Properties of Armchair Graphene Nanoribbons. NANO LETTERS 2015; 15:4883-4888. [PMID: 26134244 DOI: 10.1021/acs.nanolett.5b00399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
First-principles calculations were conducted on armchair graphene nanoribbons (AGNRs) to simulate the elastic behavior of AGNRs with hydrogen-terminated and bare edges. The results show width-dependent elastic properties with a periodicity of three, which depends on the nature of edge. The edge eigenstress and eigendisplacement models are able to predict the width-dependent nominal Young's modulus and Poisson's ratio, while the Clar structure explains the crucial role of edges in the periodically modulated size-dependent elastic properties.
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Abstract
Calculations demonstrate the occurrence of local deformations of the perfect honeycomb lattice in nanographenes to form arrangements composed of six-membered ring patterns.
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The Tube Length and Diameter Dependence of Electronic Structures in Zigzag Carbon Nanotubes. JOURNAL OF COMPUTER CHEMISTRY-JAPAN 2015. [DOI: 10.2477/jccj.2015-0037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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18
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Electronic structure and aromaticity of large-scale hexagonal graphene nanoflakes. J Chem Phys 2014; 141:214704. [DOI: 10.1063/1.4902806] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Cycloaddition of Benzyne to Armchair Single-Walled Carbon Nanotubes: [2 + 2] or [4 + 2]? Org Lett 2013; 15:5960-3. [DOI: 10.1021/ol402811b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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20
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Abstract
We propose a novel helical crystal lattice model for chiral and achiral carbon nanotubes (CNTs) where the unit cell and the helical crystal vector are defined in a unique and systematic manner for arbitrary CNTs. The small unit cell of this helical crystal lattice leads to a natural and convenient description of the electronic structure of chiral CNTs. Also, using this model, the degenerate frontier Bloch wave functions at the Γ point can be conveniently chosen by their symmetry properties. In particular, the contour of the Bloch wave functions at the Fermi level can be easily predicted for all metallic CNTs.
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Tuning aromaticity patterns and electronic properties of armchair graphene nanoribbons with chemical edge functionalisation. Phys Chem Chem Phys 2013; 15:12637-47. [DOI: 10.1039/c3cp51293b] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Carbon nanotubes as substrates for molecular spiropyran-based switches. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:394006. [PMID: 22964905 DOI: 10.1088/0953-8984/24/39/394006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present a joint theory-experiment study investigating the excitonic absorption of spiropyran-functionalized carbon nanotubes. The functionalization is promising for engineering switches on a molecular level, since spiropyrans can be reversibly switched between two different conformations, inducing a distinguishable and measurable change of optical transition energies in the substrate nanotube. Here, we address the question of whether an optical read-out of such a molecular switch is possible. Combining density matrix and density functional theory, we first calculate the excitonic absorption of pristine and functionalized nanotubes. Depending on the switching state of the attached molecule, we observe a red-shift of transition energies by about 15 meV due to the coupling of excitons with the molecular dipole moment. Then we perform experiments measuring the absorption spectrum of functionalized carbon nanotubes for both conformations of the spiropyran molecule. We find good qualitative agreement between the theoretically predicted and experimentally measured red-shift, confirming the possibility for an optical read-out of the nanotube-based molecular switch.
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Electronic Structure and Aromaticity of Graphene Nanoribbons. Chemistry 2012; 18:6183-94. [DOI: 10.1002/chem.201103977] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 03/08/2012] [Indexed: 11/06/2022]
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Redox-switchable devices based on functionalized graphene nanoribbons. NANOSCALE 2012; 4:1350-1354. [PMID: 22281659 DOI: 10.1039/c2nr11743f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The possibility of tuning the electronic properties of graphene by tailoring the morphology at the nanoscale or by chemical functionalization opens interesting perspectives towards the realization of devices for nanoelectronics. Indeed, the integration of the intrinsic high carrier mobilities of graphene with functionalities that are able to react to external stimuli allows in principle the realization of highly efficient nanostructured switches. In this paper, we report a novel approach to the design of reversible switches based on functionalized graphene nanoribbons, operating upon application of an external redox potential, which exhibit unprecedented ON/OFF ratios. The properties of the proposed systems are investigated by electronic structure and transport calculations based on density functional theory and rationalized in terms of valence-bond theory and Clar's sextet theory.
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Towards nano-organic chemistry: perspectives for a bottom-up approach to the synthesis of low-dimensional carbon nanostructures. NANOSCALE 2012; 4:369-379. [PMID: 22167069 DOI: 10.1039/c1nr11112d] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Low-dimensional carbon nanostructures, such as nanotubes and graphenes, represent one of the most promising classes of materials, in view of their potential use in nanotechnology. However, their exploitation in applications is often hindered by difficulties in their synthesis and purification. Despite the huge efforts by the research community, the production of nanostructured carbon materials with controlled properties is still beyond reach. Nonetheless, this step is nowadays mandatory for significant progresses in the realization of advanced applications and devices based on low-dimensional carbon nanostructures. Although promising alternative routes for the fabrication of nanostructured carbon materials have recently been proposed, a comprehensive understanding of the key factors governing the bottom-up assembly of simple precursors to form complex systems with tailored properties is still at its early stages. In this paper, following a survey of recent experimental efforts in the bottom-up synthesis of carbon nanostructures, we attempt to clarify generalized criteria for the design of suitable precursors that can be used as building blocks in the production of complex systems based on sp(2) carbon atoms and discuss potential synthetic strategies. In particular, the approaches presented in this feature article are based on the application of concepts borrowed from traditional organic chemistry, such as valence-bond theory and Clar sextet theory, and on their extension to the case of complex carbon nanomaterials. We also present and discuss a validation of these approaches through first-principle calculations on prototypical systems. Detailed studies on the processes involved in the bottom-up fabrication of low-dimensional carbon nanostructures are expected to pave the way for the design and optimization of precursors and efficient synthetic routes, thus allowing the development of novel materials with controlled morphology and properties that can be used in technological applications.
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Clar sextet analysis of triangular, rectangular, and honeycomb graphene antidot lattices. ACS NANO 2011; 5:523-529. [PMID: 21158482 DOI: 10.1021/nn102442h] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Pristine graphene is a semimetal and thus does not have a band gap. By making a nanometer scale periodic array of holes in the graphene sheet a band gap may form; the size of the gap is controllable by adjusting the parameters of the lattice. The hole diameter, hole geometry, lattice geometry, and the separation of the holes are parameters that all play an important role in determining the size of the band gap, which, for technological applications, should be at least of the order of tenths of an eV. We investigate four different hole configurations: the rectangular, the triangular, the rotated triangular, and the honeycomb lattice. It is found that the lattice geometry plays a crucial role for size of the band gap: the triangular arrangement displays always a sizable gap, while for the other types only particular hole separations lead to a large gap. This observation is explained using Clar sextet theory, and we find that a sufficient condition for a large gap is that the number of sextets exceeds one-third of the total number of hexagons in the unit cell. Furthermore, we investigate nonisosceles triangular structures to probe the sensitivity of the gap in triangular lattices to small changes in geometry.
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Edge effects, electronic arrangement, and aromaticity patterns on finite-length carbon nanotubes. Phys Chem Chem Phys 2011; 13:12844-57. [DOI: 10.1039/c1cp20672a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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28
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Density functional theory study on nitrogen-doped carbon nanotubes with and without oxygen adsorption: the influence of length and diameter. NEW J CHEM 2011. [DOI: 10.1039/c1nj20525k] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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29
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Anchoring Pd nanoclusters onto pristine and functionalized single-wall carbon nanotubes: A combined DFT and experimental study. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2010.08.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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30
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Clar’s Theory, π-Electron Distribution, and Geometry of Graphene Nanoribbons. J Am Chem Soc 2010; 132:3440-51. [DOI: 10.1021/ja909234y] [Citation(s) in RCA: 202] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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31
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Electronic structures of [n]-cyclacenes (n = 6–12) and short, hydrogen-capped, carbon nanotubes. Faraday Discuss 2010. [DOI: 10.1039/b906882a] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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32
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Cr(CO)3-Activated Diels-Alder Reaction on Single-Wall Carbon Nanotubes: A DFT Investigation. Chemistry 2009; 15:4182-9. [DOI: 10.1002/chem.200802440] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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34
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First-principles investigations on the functionalization of chiral and non-chiral carbon nanotubes by Diels–Alder cycloaddition reactions. Phys Chem Chem Phys 2009; 11:563-7. [DOI: 10.1039/b808152b] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Semiempirical calculations on the electronic properties of finite-length models of carbon nanotubes based on Clar sextet theory. MOLECULAR SIMULATION 2008. [DOI: 10.1080/08927020802101726] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Electronic properties and stability of graphene nanoribbons: An interpretation based on Clar sextet theory. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.09.018] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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