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0000-0001-9466-8834
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Publisher: Springer Science and Business Media LLC
Date: 07-12-2009
Abstract: Carbon nanostructures have emerged as likely candidates for a wide range of applications, driving research into novel synthetic techniques to produce nanotubes, graphene and other carbon-based materials. Single sheets of pristine graphene have been isolated from bulk graphite in small amounts by micromechanical cleavage, and larger amounts of chemically modified graphene sheets have been produced by a number of approaches. Both of these techniques make use of highly oriented pyrolitic graphite as a starting material and involve labour-intensive preparations. Here, we report the direct chemical synthesis of carbon nanosheets in gram-scale quantities in a bottom-up approach based on the common laboratory reagents ethanol and sodium, which are reacted to give an intermediate solid that is then pyrolized, yielding a fused array of graphene sheets that are dispersed by mild sonication. The ability to produce bulk graphene s les from non-graphitic precursors with a scalable, low-cost approach should take us a step closer to real-world applications of graphene.
Publisher: American Chemical Society (ACS)
Date: 02-10-2004
DOI: 10.1021/IC0492340
Abstract: The mixed-valence double salt K(3)(MnO(4))(2) crystallizes in space group P2(1)/m with Z = 2. The manganese centers Mn1 and Mn2 constitute discrete "permanganate", [Mn(VII)O(4)](-), and "manganate", [Mn(VI)O(4)](2-), ions, respectively. There is a spin-ordering transition to an antiferromagnetic state at ca. T = 5 K. The spin-density distribution in the paramagnetic phase at T = 10 K has been determined by polarized neutron diffraction, confirming that unpaired spin is largely confined to the nominal manganate ion Mn2. Through use of both Fourier refinement and maximum entropy methods, the spin on Mn1 is estimated as 1.75 +/- 1% of one unpaired electron with an upper limit of 2.5%.
Publisher: Elsevier BV
Date: 09-2014
Publisher: IEEE
Date: 02-2010
Publisher: American Chemical Society (ACS)
Date: 14-04-2021
Publisher: Elsevier BV
Date: 03-2015
Publisher: AIP Publishing
Date: 05-12-2016
DOI: 10.1063/1.4971779
Abstract: We report a reproducible enhancement of the open circuit voltage in Cu2ZnSnS4 solar cells by introduction of a very thin CeO2 interlayer between the Cu2ZnSnS4 absorber and the conventional CdS buffer. CeO2, a non-toxic earth-abundant compound, has a nearly optimal band alignment with Cu2ZnSnS4 and the two materials are lattice-matched within 0.4%. This makes it possible to achieve an epitaxial interface when growing CeO2 by chemical bath deposition at temperatures as low as 50 °C. The open circuit voltage improvement is then attributed to a decrease in the interface recombination rate through formation of a high-quality heterointerface.
Publisher: Wiley
Date: 10-12-2009
Abstract: Raman and neutron experiments using specific isotope labeling were combined in order to study the dynamics and structure of L-alanine. Inelastic neutron and Raman scattering data of C(2)H(4)(ND(2))CO(2)D are discussed in relation to the doubling of the lattice parameter a observed by means of neutron powder diffraction in C(2)D(4) (NH(2))CO(2)H. The major changes accompanying the phase transition are found in the vibrational frequencies involving the torsional vibration tau(CO(2)(-)), which is clearly affected by the hydrogen bonds between the protons of the ammonium group and the oxygen atoms of the carboxylate group. At lower temperatures the rearrangement of identifiable hydrogen bonds induces changes in the bending vibration delta(ND(3)), confirming some orientational disorder.
Publisher: Elsevier BV
Date: 02-2003
Publisher: Elsevier BV
Date: 09-2014
Publisher: IEEE
Date: 02-2008
Publisher: Wiley
Date: 03-09-2012
Abstract: The Group XIV tetratolyl series X(C(6)H(4)-CH(3))(4) (X = C, Si, Ge, Sn, Pb) were studied by using inelastic neutron scattering to measure the low-energy phonon spectra to directly access the methyl-group torsional modes. The effect of increased molecular radius as a function of the size of the central atom was shown to have direct influence on the methyl dynamics, reinforced with the findings of molecular dynamics and contact surface calculations, based upon the solid-state structures. The torsional modes in the lightest analogue were found to be predominantly intramolecular: the Si and Ge analogues have a high degree of intermolecular methyl-methyl group interactions, whilst the heaviest analogues (Sn and Pb) showed pronounced intermolecular methyl interactions with the whole phonon bath of the lattice modes.
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B924818H
Abstract: A coordination polymer, [Co(II)(bIM)(acetate)] (bIM = benzimidazole) was synthesized using a solvothermal method the complex has a two dimensional non-interpenetrated network structure and exhibits a spin-canted antiferromagnetic behaviour at low temperature and a high coercive field.
Publisher: IOP Publishing
Date: 19-02-2008
Publisher: IEEE
Date: 02-2010
Publisher: American Physical Society (APS)
Date: 02-12-2004
Publisher: Elsevier BV
Date: 2016
Publisher: IEEE
Date: 06-2013
Publisher: Elsevier BV
Date: 05-2004
Publisher: Elsevier BV
Date: 02-2015
Publisher: American Chemical Society (ACS)
Date: 18-01-2007
DOI: 10.1021/IC0611645
Abstract: Exchange mechanisms and magnetic structure in the two-dimensional cyano-bridged molecule-based magnet K2[Mn(H2O)2]3[Mo(CN)7]2.6H2O have been investigated by a combination of neutron diffraction studies on both single crystal and powder s les and theoretical DFT calculations. The experimental spin density has been deduced from a new refinement of previously obtained polarized neutron diffraction (PND) data which was collected in the ordered magnetic state at 4 K under a saturation field of 3 T performed in the C2/c space group, determined by an accurate re-evaluation of the X-ray structure. Positive spin populations were observed on the two manganese sites, and negative spin populations were observed on the molybdenum site, which provides evidence of antiferromagnetic Mo3+-Mn2+ exchange interactions through the cyano bridge. The experimental data have been compared to the results of DFT calculations. Moreover, theoretical studies reveal the predominance of the spin polarization mechanism in the Mo-C-N-Mn sequence, with the antiferromagnetic nature of the interaction being due to the overlap between the magnetic orbitals relative to manganese and molybdenum in the cyano bridging region. The magnetic structure of K2[Mn(H2O)2]3[Mo(CN)7]2.6H2O has been solved at low temperature in zero field by powder neutron diffraction measurements. The structure was found to be ferrimagnetic where the manganese and molybdenum spins are aligned along the axis in opposite directions.
Publisher: Elsevier BV
Date: 03-2000
Publisher: IOP Publishing
Date: 15-09-2006
Publisher: AIP Publishing
Date: 28-04-2014
DOI: 10.1063/1.4873715
Abstract: The heterojunctions of different n-type buffers, i.e., CdS, Zn(O,S), and In2S3 on p-type Cu2ZnSnS4 (CZTS) were investigated using X-ray Photoelectron Spectroscopy (XPS) and Near Edge X-ray Absorption Fine Structure (NEXAFS) Measurements. The band alignment of the heterojunctions formed between CZTS and the buffer materials was carefully measured. The XPS data were used to determine the Valence Band Offsets (VBO) of different buffer/CZTS heterojunctions. The Conduction Band Offset (CBO) was calculated indirectly by XPS data and directly measured by NEXAFS characterization. The CBO of the CdS/CZTS heterojunction was found to be cliff-like with CBOXPS = −0.24 ± 0.10 eV and CBONEXAFS = −0.18 ± 0.10 eV, whereas those of Zn(O,S) and In2S3 were found to be spike-like with CBOXPS = 0.92 ± 0.10 eV and CBONEXAFS = 0.87 ± 0.10 eV for Zn(O,S)/CZTS and CBOXPS = 0.41 ± 0.10 eV for In2S3/CZTS, respectively. The CZTS photovoltaic device using the spike-like In2S3 buffer was found to yield a higher open circuit voltage (Voc) than that using the cliff-like CdS buffer. However, the CBO of In2S3/CZTS is slightly higher than the optimum level and thus acts to block the flow of light-generated electrons, significantly reducing the short circuit current (Jsc) and Fill Factor (FF) and thereby limiting the efficiency. Instead, the use of a hybrid buffer for optimization of band alignment is proposed.
Publisher: IEEE
Date: 02-2010
Publisher: Elsevier BV
Date: 06-2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6CY02328B
Abstract: Water splitting over Cu–Cu 2 O/TiO 2 photocatalysts.
Publisher: Wiley
Date: 26-05-2020
Publisher: Elsevier BV
Date: 10-2005
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C0DT01531H
Abstract: A microporous metal-organic framework [Cu(3)(ipO)(2)(pyz)(2)](n), (ipO = 2-hydroxyisophthalic acid, pyz = pyrazine) was synthesized via an in situ. ligand transformation reaction. The microporous framework displays helical arrays of ipo ligands holding the Cu atoms in 2D sheets, whilst the coordination of pyz molecules acts to arrange these sheets into a microporous 3D structure. Remarkable selective sorption behaviour (>5) for H(2) over N(2) is observed and explained with molecular dynamics simulations.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5RA13499D
Abstract: High resolution of EDX image shows the bromine located on same position of PbS quantum dot.
Publisher: Elsevier BV
Date: 09-2000
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5TC01750E
Abstract: Schematic representation of the CZTS absorber and device in this study.
Publisher: Elsevier BV
Date: 02-2005
Publisher: Springer Science and Business Media LLC
Date: 22-02-2016
Publisher: IOP Publishing
Date: 29-06-2010
Publisher: Elsevier BV
Date: 07-2014
Publisher: American Chemical Society (ACS)
Date: 12-1994
DOI: 10.1021/JA00105A029
Publisher: Springer Science and Business Media LLC
Date: 23-07-2018
Publisher: Elsevier BV
Date: 08-2018
Publisher: Crossref
Date: 12-2006
Publisher: Wiley
Date: 25-04-2005
Publisher: Elsevier BV
Date: 09-2006
Publisher: Wiley
Date: 14-05-2020
Publisher: Elsevier BV
Date: 03-2014
Publisher: American Chemical Society (ACS)
Date: 03-04-2017
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B922750D
Abstract: A 3D metal-organic framework, [Na{Mn(3)(Hbtc)(2)(btc)}.5H(2)O](n) () (H(3)btc = 1,3,5-benzene tricarboxylic acid), was synthesized under hydrothermal conditions. The structure of was established by single crystal X-ray diffraction analysis crystallizes in the monoclinic space group P2/c, a = 9.753(3) A, b = 12.751(2) A, c = 14.174(4) A, beta = 109.41(1) degrees . The complex is isostructural to previously reported MIL-45 and consists of one dimensional wave like chains of carboxylate bridged hexa-coordinated Mn(ii) ions. Variable temperature magnetic susceptibility measurements revealed dominant antiferromagnetic exchange interactions and the intra-chain exchange constants J(1) = -2.4 cm(-1) and J(2) = -0.6 cm(-1) compare well with literature values for similar materials. Inter-chain interactions are expected to be very small in this compound and there is no indication of magnetic ordering phenomena in the temperature range from 300-2 K.
Publisher: American Chemical Society (ACS)
Date: 11-03-2003
DOI: 10.1021/JA029227F
Abstract: Discotic molecules have planar, disklike polyaromatic cores that can self-assemble into "molecular wires". Highly anisotropic charge transfer along the wires arises when there is sufficient intermolecular overlap of the pi-orbitals of the molecular cores. Discotic materials can be applied in molecular electronics, field-effect transistors, and-recently with record quantum efficiencies-photovoltaics (Schmidt-Mende, L. Fechtenkötter, A. Müllen, K. Moons, E. Frien, R. H. MacKenzie, J. D. Science 2001, 293, 1119). A combination of quasielastic neutron scattering (QENS) measurements with molecular dynamics simulations on the discotic molecule hexakis(n-hexyloxy)triphenylene (HAT6) shows that the dynamics of the cores and tails of discotic molecules are strongly correlated. Core and tail dynamics are not separated, the system being characterized by overall in-plane motion, on a time scale of 0.2 ps, and softer out-of-plane motions at 7 ps. Because charge transfer between the molecules is on similar time scales, these motions are relevant for the conducting properties of the materials. Both types of motion are dominated by van der Waals interactions. Small- litude in-plane motions in which the disks move over each other are almost entirely determined by tail/tail interactions, these also playing an important role in the out-of-plane motion. The QENS measurements reveal that these motions are little changed by passing from the columnar phase to the isotropic liquid phase, just above the clearing temperature. The model of four HAT6 molecules in a column reproduces the measured QENS spectrum of the liquid phase, suggesting that correlations persist within the liquid phase over about this number of disks.
Publisher: IEEE
Date: 02-2008
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7CY02219K
Abstract: Pd–Ag bimetallic and monometallic nanoparticles were decorated on g-C 3 N 4 and evaluated for their ability to produce H 2 through water splitting reactions.
Publisher: Wiley
Date: 31-08-2017
Publisher: Wiley
Date: 25-02-2019
Publisher: Crossref
Date: 2007
Publisher: MDPI AG
Date: 20-03-2019
DOI: 10.3390/NANO9030465
Abstract: Semiconductor nanocrystals or quantum dots (QDs) have unique optical and physical properties that make them potential imaging tools in biological and medical applications. However, concerns over the aqueous dispersivity, toxicity to cells, and stability in biological environments may limit the use of QDs in such applications. Here, we report an investigation into the cytotoxicity of aqueously dispersed CdSe(S) and CdSe(S)/ZnO core/shell QDs in the presence of human colorectal carcinoma cells (HCT-116) and a human skin fibroblast cell line (WS1). The cytotoxicity of the precursor solutions used in the synthesis of the CdSe(S) QDs was also determined in the presence of HCT-116 cells. CdSe(S) QDs were found to have a low toxicity at concentrations up to 100 µg/mL, with a decreased cell viability at higher concentrations, indicating a highly dose-dependent response. Meanwhile, CdSe(S)/ZnO core/shell QDs exhibited lower toxicity than uncoated QDs at higher concentrations. Confocal microscopy images of HCT-116 cells after incubation with CdSe(S) and CdSe(S)/ZnO QDs showed that the cells were stable in aqueous concentrations of 100 µg of QDs per mL, with no sign of cell necrosis, confirming the cytotoxicity data.
Publisher: Wiley
Date: 29-06-2009
Publisher: Wiley
Date: 24-07-2018
DOI: 10.1002/PIP.3061
Publisher: Wiley
Date: 18-09-0044
Abstract: Colloidal quantum dots (QDs) are promising candidate materials for photovoltaics (PV) owing to the tunable bandgap and low-cost solution processability. Lead selenide (PbSe) QDs are particularly attractive to PV applications due to the efficient multiple-exciton generation and carrier transportation. However, surface defects arising from the oxidation of the PbSe QDs have been the major limitation for their development in PV. Here, a new passivation method for chlorinated PbSe QDs via ion exchange with cesium lead halide (Br, I) perovskite nanocrystals is reported. The surface chloride ions on the as-synthesized QDs can be partially exchanged with bromide or iodide ions from the perovskite nanocrystals, hence forming a hybrid halide passivation. Consistent with the improved photoluminescence quantum yield, the ch ion PV device fabricated with these PbSe QDs achieves a PCE of 8.2%, compared to 7.3% of that fabricated with the untreated QDs. This new method also leads to devices with excellent air-stability, retaining at least 93% of their initial PCEs after being stored in ambient conditions for 57 d. This is considered as the first reported PbSe QD solar cell with a PCE of over 8% to date.
Publisher: Wiley
Date: 09-06-2016
Publisher: Pleiades Publishing Ltd
Date: 05-2007
Publisher: Elsevier BV
Date: 12-2013
Publisher: Elsevier BV
Date: 02-2001
Publisher: American Chemical Society (ACS)
Date: 23-05-2018
Publisher: American Chemical Society (ACS)
Date: 14-12-2002
DOI: 10.1021/JP0042213
Publisher: Elsevier BV
Date: 08-2011
Publisher: Wiley
Date: 19-02-2007
Abstract: Muon Spin Relaxation and Avoided Level Crossing (ALC) measurements of ferrocene are reported. The main features observed are five high field resonances in the ALC spectrum at about 3.26, 2.44, 2.04, 1.19 and 1.17 T, for the low-temperature phase at 18 K. The high-temperature phase at 295 K shows that only the last feature shifted down to about 0.49 T and a muon spin relaxation peak at about 0.106 T which approaches zero field when reaching the phase transition temperature of 164 K. A model involving three muoniated radicals, two with muonium addition to the cyclopentadienyl ring and the other to the metal atom, is postulated to rationalise these observations. A theoretical treatment involving spin-orbit coupling is found to be required to understand the Fe-Mu adduct, where an interesting interplay between the ferrocene ring dynamics and the spin-orbit coupling of the unpaired electron is shown to be important. The limiting temperature above which the full effect of spin-orbit interaction is observable in the muSR spectra of ferrocene was estimated to be 584 K. Correlation time for the ring rotation dynamics of the Fe-Mu radical at this temperature is 3.2 ps. Estimated electron g values and the changes in zero-field splittings for this temperature range are also reported.
Publisher: American Physical Society (APS)
Date: 22-11-2010
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B922698M
Publisher: Elsevier BV
Date: 07-2004
Publisher: Elsevier BV
Date: 08-2003
Publisher: International Union of Crystallography (IUCr)
Date: 16-03-2005
DOI: 10.1107/S0108768104034007
Abstract: The low-temperature structure of hexamethylbenzene has been determined from neutron powder diffraction data and found to differ from the room-temperature phase predominantly by a translation of molecular planes to a form a cubic close-packed type structure. By performing measurements as a function of temperature, the role of thermally induced agitation of the molecular units in the first-order phase transition is clearly demonstrated.
Publisher: Elsevier BV
Date: 07-2016
DOI: 10.1016/J.MSEC.2016.03.061
Abstract: Highly luminescent quantum dots (QDs) that emit in the visible spectrum are of interest to a number of imaging technologies, not least that of biological s les. One issue that hinders the application of luminescent markers in biology is the potential toxicity of the fluorophore. Here we show that hydrothermally synthesized ZnSe(S) QDs have low cytotoxicity to both human colorectal carcinoma cells (HCT-116) and human skin fibroblast cells (WS1). The QDs exhibited a high degree of crystallinity, with a strong blue photoluminescence at up to 29% quantum yield relative to 4',6-diamidino-2-phenylindole (DAPI) without post-synthetic UV-irradiation. Confocal microscopy images obtained of HCT-116 cells after incubation with the QDs highlighted the stability of the particles in cell media. Cytotoxicity studies showed that both HCT-116 and WS1 cells retain 100% viability after treatment with the QDs at concentrations up to 0.5g/L, which makes them of potential use in biological imaging applications.
Publisher: AIP Publishing
Date: 11-2004
DOI: 10.1063/1.1814819
Abstract: The fundamental magnetic interactions of Pr2Fe17 are studied by inelastic neutron scattering and anisotropy field measurements. Data analysis confirms the presence of three magnetically inequivalent sites, and reveals an exceptionally large value of the exchange field. The unexpected importance of J-mixing effects in the description of the ground-state properties of Pr2Fe17 is shown, and possible applications of related compounds are envisaged.
Publisher: American Chemical Society (ACS)
Date: 14-08-2003
DOI: 10.1021/IC034110T
Abstract: Spectroscopic, structural, and magnetic data are presented for Fe(C(3)H(4)N(2))(6)(NO(3))(2), which facilitate a precise definition of the electronic and molecular structure of the [Fe(Im)(6)](2+) cation. The structure was determined at 120(1) K by X-ray diffraction methods. The salt crystallizes in the trigonal space group R3 with unit-cell parameters a = 12.4380(14) A, c = 14.5511(18) A, and Z = 3. All the imidazole ligands are equivalent with an Fe-N bond distance of 2.204(1) A. Variable-temperature inelastic neutron scattering (INS) measurements identify a cold magnetic transition at 19.4(2) cm(-1) and a hot transition at 75.7(6) cm(-1). The data are interpreted using a ligand field Hamiltonian acting in the weak-field (5)D basis, from which the diagonal trigonal field splitting of the (5)T(2g) (O(h)) term is estimated as approximately 485 cm(-1), with the (5)A(g) (S(6)) component lower lying. High-field multifrequency (HFMF) EPR data and measurements of the magnetic susceptibility are also reported and can be satisfactorily modeled using the energies and wave functions derived from analysis of the INS data. The electronic and molecular structures are related through angular overlap model calculations, treating the imidazole ligand as a weak pi-donor.
Publisher: Wiley
Date: 11-09-2014
Abstract: The crystal structure of pentamethylbenzene has been obtained for the first time with the use of synchrotron radiation, whilst the low-energy spectrum of lattice dynamics, dominated by the methyl group torsions, was obtained using inelastic neutron scattering. The effect of symmetry lowering by the removal of a single methyl group relative to hexamethylbenzene has been investigated, including the role that this plays in the charge-transfer characteristics of complexes formed with tetracyanoethylene.
Publisher: Crossref
Date: 11-1997
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5CE00328H
Abstract: Inelastic neutron scattering is used to directly probe the effect of intermolecular interactions in the text-book co-crystal hexamethylbenzene : tricyanobenzene.
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/C0DT00600A
Abstract: The use of 1,3,5-benzene tricarboxylic acid (H(3)btc) as an organic linker has allowed us to achieve the rational design of two pairs of isostructural coordination polymers having molecular formulae [M(2)(btc)(F)](n) (M(ii) = Mn (1), Co (2)) and [M(3)(btc)(Hbtc)(OH)(H(2)O)(11)](n) (M(ii) = Fe (3), Co (4)) where btc and Hbtc represent the fully and doubly de-protonated tricarboxylates respectively. These compounds were synthesized using hydrothermal methods and characterized by thermal analysis and variable temperature magnetic measurements. The X-ray analysis reveals that compounds 1 and 2 crystallize in the monoclinic space group C2/c while compounds 3 and 4 crystallize in the monoclinic space group C2. Compounds 1 and 2 feature fluoride bridged 1D metal chains linked together via carboxylate groups of btc, whilst compounds 3 and 4 consist of 1D zigzag chains having strong hydrogen bonds with neighbouring chains. Variable temperature magnetic measurements show an overall antiferromagnetic behaviour for compounds 1, 2 and 4, with no indication of magnetic ordering phenomena in the temperature range from 300-2 K. As 3 and 4 are isostructural, we assume that the magnetic properties are similar.
Publisher: IOP Publishing
Date: 11-12-2005
DOI: 10.1088/0953-8984/17/1/010
Abstract: We describe the results of an inelastic neutron scattering measurement of the magnetic excitations in SrCaGaMnO(5+δ), a quasi-two-dimensional compound whose structure consists of layers of MnO(6) octahedra separated by layers of GaO(4) tetrahedra (the brownmillerite structure), and Ca(2.5)Sr(0.5)Mn(2)GaO(8), a bilayered brownmillerite. In both materials, a band of magnetic scattering appears below the magnetic ordering temperature which can be associated with magnon excitations. Our measurements allow us to provide an estimate for the intraplane exchange constant in both materials, which we find to be 3.4(4) meV for SrCaGaMnO(5+δ) and 2.2(4) meV for Ca(2.5)Sr(0.5)Mn(2)GaO(8).
Publisher: Elsevier BV
Date: 10-2005
Publisher: Elsevier BV
Date: 02-2014
Publisher: American Chemical Society (ACS)
Date: 23-03-2005
DOI: 10.1021/JP044453S
Abstract: Polyelectrolyte materials are an interesting class of electrolytes for use in fuel cell and battery applications. Poly(para-phenylene terephthalamide) (PPTA, Kevlar) is a liquid crystalline polymer that, when sulfonated, is a polyelectrolyte that exhibits moderate ion conductivity at elevated temperatures. In this work, quasi-elastic neutron scattering (QENS) experiments were performed to gain insight into the effect of the presence of lithium counterions on the chain dynamics in the material. It was found that the addition of lithium ions decreases the dynamics of the chains. Additionally, the binding of lithium ions to the sulfonic acids groups was investigated by density functional theory (DFT) calculations. It was found that the local surroundings of the sulfonic acid group have very little effect on the lithium-ion binding energy. Binding energies for a variety of different systems were all calculated to be around 150 kcal/mol. The DFT calculations also show the existence of a structure in which a single lithium ion interacts with two sulfonic acid moieties on different chains. The formation of such "electrostatic cross-links" is believed to be the source of the increased tendency to aggregate and the reduced dynamics in the presence of lithium ions.
Publisher: IEEE
Date: 02-2014
Publisher: Elsevier BV
Date: 11-2015
Publisher: Walter de Gruyter GmbH
Date: 10-2008
Abstract: The collective motions in liquid deuterium fluoride (DF) have been investigated by neutron scattering motivated by a MD simulation, which predicted an optic-type mode at small momentum transfers. Spectra of the measured longitudinal current correlation function show two modes. The lower frequency one originates from acoustic-type movements. The intensity of the higher frequency excitation can be attributed to an out of phase motion of neighboring DF molecules, an optic-type mode. Both, the frequencies and the intensity distribution in momentum space agree well with the MD simulation. The widths of the experimental spectra exceed the widths from the MD simulation and indicate missing relaxation processes in the simulation.
Publisher: Wiley
Date: 14-04-2016
Publisher: Elsevier BV
Date: 07-2004
Publisher: Elsevier BV
Date: 10-2007
Publisher: Elsevier BV
Date: 07-2004
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5TA05813A
Abstract: By using sulfur atmosphere, Na compound, and suitable precursor composition, pure-sulfide Cu 2 ZnSnS 4 solar cells with 4.83% efficiency are fabricated by forming large grains from metastable wurtzite nanocrystals.
Publisher: Springer Science and Business Media LLC
Date: 06-2012
Publisher: Trans Tech Publications, Ltd.
Date: 06-2010
DOI: 10.4028/WWW.SCIENTIFIC.NET/SSP.162.261
Abstract: Recent interest in nanostructured titanium dioxide (TiO2) has been driven by the excellent photocatalytic and optical properties exhibited by the anatase and rutile phases. This article highlights the relationship between reaction conditions and the resultant nanostructured TiO2 and is primarily focused on wet chemical synthetic methods. We show that solvothermal syntheses of nano-TiO2 can be rationalised by making use of a diffusion-controlled model accounting for physical properties of the solvent such as the vapour-pressure, allowing the prediction and control the phase, size and type of nanostructured TiO2 product. This external control makes it possible for the systematic synthesis of TiO2 nanostructures via parameters such as the solvent chain length, the reaction temperature and time, and also by the addition of surfactants, providing the ability to design and tailor the nanostructured TiO2, which is vital for the optimal application of these nanostructures in photocatalytic or optical applications.
Publisher: American Chemical Society (ACS)
Date: 13-10-2011
DOI: 10.1021/NL202866Q
Abstract: Here, we present the first muon spectroscopy investigation of graphene, focused on chemically produced, gram-scale s les, appropriate to the large muon penetration depth. We have observed an evident muon spin precession, usually the fingerprint of magnetic order, but here demonstrated to originate from muon-hydrogen nuclear dipolar interactions. This is attributed to the formation of CHMu (analogous to CH(2)) groups, stable up to 1250 K where the signal still persists. The relatively large signal litude demonstrates an extraordinary hydrogen capture cross section of CH units. These results also rule out the formation of ferromagnetic or antiferromagnetic order in chemically synthesized graphene s les.
Publisher: American Chemical Society (ACS)
Date: 19-05-2016
Publisher: Elsevier BV
Date: 2012
Publisher: American Chemical Society (ACS)
Date: 03-08-2010
DOI: 10.1021/CG1007389
Publisher: Crossref
Date: 11-1997
Publisher: Crossref
Date: 11-1997
Publisher: Springer Science and Business Media LLC
Date: 26-03-2014
Publisher: Elsevier BV
Date: 10-2014
Publisher: Wiley
Date: 16-04-2018
Publisher: Springer Science and Business Media LLC
Date: 07-2017
DOI: 10.1038/AM.2017.103
Publisher: AIP Publishing
Date: 17-07-2003
DOI: 10.1063/1.1587118
Abstract: The exceptionally broad feature at ∼3025 cm−1 observed in the Raman spectrum of chloroform dissolved in liquid sulfur dioxide is shown to be due to the triple combination mode, ν1+ν2+ν3, of sulfur dioxide gaining intensity by mixing with the fundamental C–H stretching mode of chloroform. Investigation of a number of similar systems shows that this broadening is unique to this system and is certainly not heterogeneous broadening due to C–H hydrogen bonding to SO2. This therefore is probably the first observation of the phenomenon of intermolecular Fermi resonance, between molecularly distinct species.
Publisher: Elsevier BV
Date: 03-2012
Publisher: Elsevier BV
Date: 03-2000
Publisher: American Chemical Society (ACS)
Date: 24-03-2021
Publisher: Springer Science and Business Media LLC
Date: 06-2023
DOI: 10.1007/S10853-023-08629-7
Abstract: Chemical vapor deposition (CVD) has great potential to produce graphene films at large-scale. However, CVD production of graphene films usually requires a catalytic metal substrate, such as copper. Recently we have developed a new method to grow graphene films directly on crystalline silicon wafers with a thermally grown 300 nm oxide layer, using a seeded-CVD growth approach. The use of methane as the feedstock and optimized graphene seeds has led to enhanced film formation, which SEM, X-ray photo-electron and Raman spectroscopies indicate consist of graphene layers formed by the coalescence of expanding “graphene seeds”. The resultant films have regions of single graphene crystallites within them as a result of lateral growth of the seeds. In addition, we have observed that the unilateral conductivity of the graphene films is consistent with the presence of graphene nanoribbons and as such has potential application in device fabrication.
Publisher: American Chemical Society (ACS)
Date: 03-2017
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8TC03599G
Abstract: The antimony-doped tin oxide buffer layer greatly improve the extraction of carriers in a PbSe QD solar cell.
Publisher: IOP Publishing
Date: 19-02-2008
Publisher: Wiley
Date: 04-10-2017
Publisher: Elsevier BV
Date: 02-2010
Publisher: Pleiades Publishing Ltd
Date: 06-2011
Publisher: Wiley
Date: 10-04-2022
Abstract: The performance of non‐fullerene, polymer bulk heterojunction (BHJ) organic photovoltaic devices has a significant correlation with the molecular morphology of the donor and acceptor. The authors show that small organic molecules coordinated to a metal oxide, an electron transport seed layer (ETSL), can profoundly modify the donor:acceptor molecular morphology of inverted organic photovoltaic (OPV) devices. Using grazing incidence wide angle X‐ray scattering (GIWAXS), the authors show that a PTB7‐Th:IEICO‐4F BHJ active layer has a higher degree of face‐on molecular alignment on ETSL‐1 (biphenyl‐4,4′‐dicarboxylic acid, coordinated to ZnO), whilst for naphthalene‐2,6‐dicarboxylic acid coordinated to ZnO (ETSL‐2), it is reduced. Devices of PTB7‐Th:IEICO‐4F BHJ prepared on ETSL‐1 had a 19.91% increase in the average power conversion efficiency (PCE), a 1.56% increase in the fill factor (FF), and a 16.66 ± 0.2% enhancement in the short circuit current density. The observed improvements are believed to be due to significant modifications to the oxide‐BHJ interfacial region of ETSL‐1, namely the elimination of nano‐ridges and defect centers, along with an enhanced wettability. These factors can be correlated with the enhanced device performances, leading to the conclusion that the modulation of the molecular morphology of donor:acceptor blends by ETSL‐1 has a broad impact on improving OPV cell efficiencies.
Publisher: American Chemical Society (ACS)
Date: 16-11-2016
Abstract: High activity, a low rate of CO poisoning, and long-term stability of Pd electro-catalysts are necessary for practical use as an anode material in direct formic acid fuel cells. Achieving a high degree of Pd nanoparticle dispersion on a carbon support, without agglomeration, while maintaining a facile electron transfer through the catalyst surface are two challenging tasks to be overcome in fulfilling this aim. Herein, we report the effect of addition of La/La-oxides on the efficiency of Pd nanoparticles supported on reduced graphene oxide (rGO) for formic acid electro-oxidation reaction. A series of electro-catalysts with different Pd-La molar ratios were successfully synthesized and characterized using a range of techniques including PXRD, XPS, TEM, FTIR, and Raman spectroscopy and then tested as anode materials for direct formic acid fuel cells. We explore that the lanthanum species (La/La-oxide) significantly promote the activity and stability of Pd catalyst toward electrocatalytic oxidation of formic acid. The metallic ratio is found to be critical, and the activity order of various catalysts is observed as follows Pd
Publisher: Royal Society of Chemistry (RSC)
Date: 2006
DOI: 10.1039/B504987C
Publisher: American Chemical Society (ACS)
Date: 08-1993
DOI: 10.1021/JA00070A025
Publisher: IEEE
Date: 02-2010
Publisher: Royal Society of Chemistry (RSC)
Date: 2001
DOI: 10.1039/B102321G
Publisher: CSIRO Publishing
Date: 2013
DOI: 10.1071/CH13332
Abstract: We report the metal-catalyst-free production of multiwalled carbon nanotubes and nanobubbles, in a chemical reduction of hexachlorobenzene by metallic sodium, giving high yields (in excess of 80 %) and at temperatures as low as 190°C for multiwalled carbon nanotubes and 100°C for nanobubble formation. The carbon nanotube s les produced under solvothermal conditions were found to consist of large bundles of nanotubes ( µm) consistent with a facial growth from the surface of the molten metal. Meanwhile, the nanobubbles produced under ambient pressure were found to be small (≤1 µm), polydispersed (smallest ~50 nm), and the bulk to have a large microporous area. With the regulatory complexities and high environmental and economic costs of remediating waste containing highly hazardous halogenated aromatic chemicals, necessitating high-temperature incineration under strictly controlled conditions, this low-temperature, low-cost chemical degradation of hexachlorobenzene is of great potential as a scalable and workable remediation technology.
Publisher: Elsevier BV
Date: 12-2013
Publisher: Elsevier BV
Date: 11-2006
Publisher: Elsevier BV
Date: 11-2006
Publisher: Elsevier BV
Date: 04-2000
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6DT00517A
Abstract: The relatively ubiquitous mononuclear inorganic coordination complex tris(acetylaceonate) iron( iii ) has been studied using neutron scattering techniques. The molecular dynamics are shown to be dominated by motions of the highly flexible ligand shell in a non-chiral space group.
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2009
End Date: 2009
Funder: Australian Research Council
View Funded ActivityStart Date: 2017
End Date: 2021
Funder: Australian Research Council
View Funded ActivityStart Date: 2010
End Date: 2010
Funder: Australian Research Council
View Funded ActivityStart Date: 2007
End Date: 2007
Funder: Australian Research Council
View Funded ActivityStart Date: 2008
End Date: 2010
Funder: Australian Research Council
View Funded ActivityStart Date: 2008
End Date: 2008
Funder: Australian Research Council
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