ORCID Profile
0000-0002-3711-332X
Current Organisation
Institute for Research in Fundamental Sciences
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Publisher: Wiley
Date: 03-08-2012
Publisher: Proceedings of the National Academy of Sciences
Date: 19-09-2016
Abstract: Bending of a thin plate simultaneously involves contraction and stretching of matter relative to a neutral plane, and tensile rigidity dictates the ability of a thin platelet to be bent. If graphene or graphene oxide (GO) were actually behaving as thin platelets, they would display high bending rigidity. Bending measurements for atomic monolayers remain particularly challenging because of their difficult manipulation. We quantitatively measure the GO bending rigidity by characterizing the flattening of thermal undulations in response to shear forces in solution. The bending modulus is found to be 1 kT , which is about two orders of magnitude lower than the bending rigidity of neat graphene. Amazingly, the high stiffness of GO is associated with an unexpected low bending modulus.
Publisher: Springer Science and Business Media LLC
Date: 29-11-2018
DOI: 10.1038/S41467-018-07396-3
Abstract: Silicon-based impurities are ubiquitous in natural graphite. However, their role as a contaminant in exfoliated graphene and their influence on devices have been overlooked. Herein atomic resolution microscopy is used to highlight the existence of silicon-based contamination on various solution-processed graphene. We found these impurities are extremely persistent and thus utilising high purity graphite as a precursor is the only route to produce silicon-free graphene. These impurities are found to h er the effective utilisation of graphene in whereby surface area is of paramount importance. When non-contaminated graphene is used to fabricate supercapacitor microelectrodes, a capacitance value closest to the predicted theoretical capacitance for graphene is obtained. We also demonstrate a versatile humidity sensor made from pure graphene oxide which achieves the highest sensitivity and the lowest limit of detection ever reported. Our findings constitute a vital milestone to achieve commercially viable and high performance graphene-based devices.
Publisher: Springer Science and Business Media LLC
Date: 17-09-2018
Publisher: Elsevier BV
Date: 02-2020
Publisher: Frontiers Media SA
Date: 04-08-2014
Publisher: IOP Publishing
Date: 17-01-2011
DOI: 10.1088/0022-3727/44/5/055402
Abstract: Transparent TiO 2 thin films were deposited on soda-lime glass substrates via the sol–gel method using a nanocrystalline TiO 2 sol solution prepared at room temperature employing the dip-coating method. The effects of pH on crystallinity, particle size and stability of the synthesized TiO 2 sols were investigated, systematically. TiO 2 thin films were thickened by means of a sequential dip-coating process. The TiO 2 films were transparent and exhibited proper adherence. The effects of thickness and annealing temperature on the structural and optical properties of the thin films were evaluated. The prepared powder was crystalline without any thermal treatment. The crystallite size of the particles (anatase) was in the range 4.2–12.1 nm depending on the initial pH value. Although only the anatase phase was observed at room temperature and 400 °C, a further increase in annealing temperature up to 700 °C resulted in the formation of the rutile phase. Even at high annealing temperatures, fairly smooth and homogeneous surfaces with no cracks and pores were observed. It was demonstrated that the films were transparent in the visible region with characteristic absorption in the UV region. Band gap of the as-deposited film was estimated to be 3.34 eV and was found to decrease with increasing annealing temperature.
Publisher: Elsevier BV
Date: 09-2013
Publisher: Elsevier BV
Date: 02-2019
Publisher: World Scientific Pub Co Pte Lt
Date: 30-07-2008
DOI: 10.1142/S0217979208047808
Abstract: Titanium dioxide nanoparticles have great potential for use in photocatalytic applications, cosmetics, white pigments and so on. In this paper, the effect of milling time on particle size, morphology and phase composition of TiO 2 nanoparticles, prepared by mechanochemical method, was investigated by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). TiO 2 nanoparticles were prepared by the use of high energy ball milling of titanyl sulphate ( TiOSO 4 ) and NaCl powders as the starting mixture in different milling durations. The milled powder was annealed at 700°C for 30 min. The NaCl powder, used as the diluent phase, was removed by washing the annealed powder with distilled water. It was found that with increasing milling time, decrease in the size of equiaxed spherical particles and increase in temperature of anatase to rutile transformation ( A → R ) can be observed.
Publisher: Wiley
Date: 23-11-2017
Publisher: Springer Science and Business Media LLC
Date: 24-10-2023
Publisher: Wiley
Date: 30-01-2014
Publisher: Wiley
Date: 15-11-2013
Publisher: World Scientific Pub Co Pte Lt
Date: 2012
DOI: 10.1142/S2010194512002450
Abstract: In order to translate the superior properties of carbon nanofibers (CNFs) to macro-scale structures, an electrospinning route capable of placing CNFs into a continuous nano-scale composite fibril is introduced. In this work, composite fibers were produced by electrospinning solution of polyacrylonitrile ( PAN ) with carbon nanofibers dispersed in dimethylformamide ( DMF ), which is an effective solvent for carbon nanofibers. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) demonstrated rough and globular surfaces on the CNF containing fibers. Raman spectra confirmed the presence of CNFs in the polymer fibers prepared employing the electrospinning method. Raman observation served as the direct evidence of successful filling of PAN fibers with CNFs and complemented the results obtained by SEM and AFM studies.
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2CP40410A
Abstract: Here, we report the fabrication of self-organized titania (TiO(2)) nanotube array supercapacitor electrodes through controlled phase transformation of TiO(2), with aerial capacitances as high as 2.6 mF cm(-2), which far exceeds the values so far reported in the literature. The role of phase transformation in the electrochemical charge-discharge behaviour of nanocrystalline TiO(2) nanotubes is investigated and discussed in detail. The ease of synthesis and the exceptional electrochemical properties make these nanotube arrays an alternative candidate for use in energy storage devices.
Publisher: American Chemical Society (ACS)
Date: 04-05-2015
DOI: 10.1021/JP512165Q
Publisher: American Chemical Society (ACS)
Date: 17-02-2014
DOI: 10.1021/NN406026Z
Abstract: The successful commercialization of smart wearable garments is hindered by the lack of fully integrated carbon-based energy storage devices into smart wearables. Since electrodes are the active components that determine the performance of energy storage systems, it is important to rationally design and engineer hierarchical architectures atboth the nano- and macroscale that can enjoy all of the necessary requirements for a perfect electrode. Here we demonstrate a large-scale flexible fabrication of highly porous high-performance multifunctional graphene oxide (GO) and rGO fibers and yarns by taking advantage of the intrinsic soft self-assembly behavior of ultralarge graphene oxide liquid crystalline dispersions. The produced yarns, which are the only practical form of these architectures for real-life device applications, were found to be mechanically robust (Young's modulus in excess of 29 GPa) and exhibited high native electrical conductivity (2508 ± 632 S m(-1)) and exceptionally high specific surface area (2605 m(2) g(-1) before reduction and 2210 m(2) g(-1) after reduction). Furthermore, the highly porous nature of these architectures enabled us to translate the superior electrochemical properties of in idual graphene sheets into practical everyday use devices with complex geometrical architectures. The as-prepared final architectures exhibited an open network structure with a continuous ion transport network, resulting in unrivaled charge storage capacity (409 F g(-1) at 1 A g(-1)) and rate capability (56 F g(-1) at 100 A g(-1)) while maintaining their strong flexible nature.
Publisher: Springer Science and Business Media LLC
Date: 11-03-2021
Publisher: Elsevier BV
Date: 02-2014
Publisher: Springer Science and Business Media LLC
Date: 12-02-2021
DOI: 10.1007/S42452-021-04182-7
Abstract: The significant breakthroughs of flexible gel electrolytes have attracted extensive attention in modern wearable electronic gadgets. The lack of all-around high-performing gels limits the advantages of such devices for practical applications. To this end, developing a multi-functional gel architecture with superior ionic conductivity while enjoying good mechanical flexibility is a bottleneck to overcome. Herein, an architecturally engineered gel, based on PVA and H 3 PO 4 with different molecular weights of PVA for various PVA/H 3 PO 4 ratios, was developed. The results show the dependence of ionic conductivity on molecular weight and also charge carrier concentration. Consequently, fine-tuning of PVA-based gels through a simple yet systematic and well-regulated strategy to achieve highly ion-conducting gels, with the highest ionic conductivity of 14.75 ± 1.39 mS cm -1 have been made to fulfill the requirement of flexible devices. More importantly, gel electrolytes possess good mechanical robustness while exhibiting high-elasticity (%766.66 ± 59.73), making it an appropriate candidate for flexible devices.
Publisher: Wiley
Date: 11-07-2014
Publisher: Elsevier BV
Date: 08-2008
Publisher: Informa UK Limited
Date: 12-2008
Publisher: Wiley
Date: 27-05-2013
Publisher: American Association for the Advancement of Science (AAAS)
Date: 28-05-2021
Abstract: Accurate determination of dielectric function in the vacuum UV range enables the precise computation of Casimir-vdW forces.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6NR03681C
Abstract: Engineered molybdenum disulfide (MoS 2 ) crystals with preferred orientation can readily exfoliate into ultra-large MoS 2 sheets that form liquid crystalline dispersions in water.
Publisher: World Scientific Pub Co Pte Lt
Date: 2012
DOI: 10.1142/S2010194512002401
Abstract: Nanocomposite fiber materials, particularly those constructed with uniform reinforcements, have been sought for a long time in materials science. The hoped-for enhancement of the properties of polymer–nanofiber composites have remained elusive, owing in part to the difficulties in performing mechanical measurements. Harnessing the strength of atomic force spectroscopy therefore offers a new handle for the measurement of mechanical properties such as elastic modulus. The paper, here, addresses distance dependent measurements (DDM) performed on the multi-walled carbon nanofiber (CNF) reinforced composite fibers. To quantitatively measure the elastic modulus of nanocomposite materials, measurements were carried out on different points on the surface of the s le and Force-Distance curves were then plotted. The obtained results fairly agree to previously measured values. The great improvement in elastic modulus was achieved without sacrificing the mechanical strength and stiffness of the polymer, and with minimal weight penalty.
Publisher: Academic World Research
Date: 10-2020
Publisher: American Chemical Society (ACS)
Date: 02-07-2015
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3RA44973D
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4CP03177F
Abstract: Fine-tuning of the bandgap structure of undoped highly ordered TiO 2 nanotube arrays for efficient photo-electrochemical water oxidation.
Publisher: IOP Publishing
Date: 13-05-2009
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D1TA09356H
Abstract: Low electrostatic bending stiffness of graphene oxide sheets determines the conformation and consequently their environmental fate in aquatic environments.
Publisher: Elsevier BV
Date: 05-2009
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1EE01039E
Publisher: Wiley
Date: 30-09-2016
Publisher: Springer Science and Business Media LLC
Date: 2011
Abstract: Processing graphene and graphene polymer nanocomposites in an aqueous medium has always been a big challenge due to the hydrophobic nature of graphene (or reduced graphene oxide) nanosheets. In this work, a waterborne latex of polyurethane has been used both as the matrix material for embedding the graphene nanosheets and as a unique stabilizer to help produce an up to 5 wt% graphene/PU nanocomposites. The graphene oxide olyurethane latex aqueous suspension is reduced in-situ using hydrazine, without any trace of aggregation/agglomeration upon completion of the reduction process, which would otherwise have occurred severely were PU not present. A highly aligned nanostructure is produced when graphene content is increased beyond 2 wt%, resulting in a remarkable improvement in electrical and mechanical properties of the nanocomposite. The exceptionally low electrical percolation threshold of 0.078%, as well as 21-fold and 14 fold increases in tensile modulus and strength, respectively, have been attained thanks to the alignment of graphene nanosheets in the polymeric matrix.
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C1EE02784K
Publisher: Elsevier BV
Date: 05-2012
Publisher: World Scientific Pub Co Pte Lt
Date: 2012
DOI: 10.1142/S2010194512002553
Abstract: In this study, TiO 2 / PAN -based fibers were prepared by electrospinning a composite solution containing both the desirable contents of TiO 2 and a 10 wt. % PAN polymer solution dissolved in N , N -dimethylformamide. The TiO 2 loaded electrospun PAN nanofibers were then carbonized at 1000 °C in N 2 atmosphere furnace after stabilization at 230 °C in air. Then CNF / TiO 2 nanofibers were oxidized at 450 °C in air. The morphology and structure of the TiO 2 -embeded carbon nanofibers were investigated by SEM and Raman spectroscopy. Specific surface area was determined using BET equation from N 2 adsorption analysis. Photocatalytic tests were conducted in a UV illuminated set-up specialized for the filters using ethanol vapor. The results have shown that ethanol vapor was efficiently degraded on TiO 2 / CNF composite nanofiber mat under UV illumination. The aim of this study was to further investigate the feasibility of TiO 2 / ACF for practical indoor air purification.
Publisher: Wiley
Date: 03-06-2011
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3MH00050H
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3MH00144J
Abstract: Ultra-large graphene oxide sheets exhibit unique viscoelastic properties, making them a new class of soft material. We provide fundamental insights enabling development of various fabrication techniques utilizing this 2D material.
Publisher: Elsevier BV
Date: 09-2020
Publisher: Wiley
Date: 17-10-2022
Abstract: Van der Waals (vdW) integration of two dimensional (2D) crystals into functional heterostructures emerges as a powerful tool to design new materials with fine‐tuned physical properties at an unprecedented precision. The intermolecular forces governing the assembly of vdW heterostructures are investigated by first‐principles models, yet translating the outcome of these models to macroscopic observables in layered crystals is missing. Establishing this connection is, therefore, crucial for ultimately designing advanced materials of choice‐tailoring the composition to functional device properties. Herein, components from both vdW and non‐vdW forces are integrated to build a comprehensive framework that can quantitatively describe the dynamics of these forces in action. Specifically, it is shown that the optical band gap of layered crystals possesses a peculiar ionic character that works as a quantitative indicator of non‐vdW forces. Using these two components, it is then described why only a narrow range of exfoliation energies for this class of materials is observed. These findings unlock the microscopic origin of universal binding energy in layered crystals and provide a general protocol to identify and synthesize new crystals to regulate vdW coupling in the next generation of heterostructures.
Publisher: American Chemical Society (ACS)
Date: 22-04-2013
DOI: 10.1021/NN305906Z
Abstract: We introduce soft self-assembly of ultralarge liquid crystalline (LC) graphene oxide (GO) sheets in a wide range of organic solvents overcoming the practical limitations imposed on LC GO processing in water. This expands the number of known solvents which can support hiphilic self-assembly to ethanol, acetone, tetrahydrofuran, N-dimethylformamide, N-cyclohexyl-2-pyrrolidone, and a number of other organic solvents, many of which were not known to afford solvophobic self-assembly prior to this report. The LC behavior of the as-prepared GO sheets in organic solvents has enabled us to disperse and organize substantial amounts of aggregate-free single-walled carbon nanotubes (SWNTs, up to 10 wt %) without compromise in LC properties. The as-prepared LC GO-SWNT dispersions were employed to achieve self-assembled layer-by-layer multifunctional 3D hybrid architectures comprising SWNTs and GO with unrivalled superior mechanical properties (Young's modulus in excess of 50 GPa and tensile strength of more than 500 MPa).
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0CP02054K
Abstract: We report the synthesis of self-organized titania nanotubes and nanocrystalline titania powders employing an alternative and novel approach. Integrating these nanostructures in a binder-free working electrode improved the capacitance up to 911 μF cm(-2), which is around one to two orders of magnitude higher than the conventional electric double layer capacitors.
Publisher: Wiley
Date: 06-05-2013
DOI: 10.1111/JACE.12371
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2JM30590A
Publisher: Elsevier BV
Date: 12-2019
Publisher: Wiley
Date: 29-03-2016
Location: Australia
Location: Iran (Islamic Republic of)
Location: Iran (Islamic Republic of)
Location: Australia
Location: Iran (Islamic Republic of)
No related grants have been discovered for Seyed Hamed Aboutalebi.