Nanoscale (Nanoscale )

Description

  • Impact factor
    6.73
  • 5-year impact
    6.26
  • Cited half-life
    1.70
  • Immediacy index
    1.17
  • Eigenfactor
    0.03
  • Article influence
    1.60
  • ISSN
    2040-3372

Publications in this journal

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    ABSTRACT: Extending the capabilities of electron tomography with advanced imaging techniques and novel data processing methods, can augment the information content in three-dimensional (3D) reconstructions from projections taken in the transmission electron microscope (TEM). In this work we present the application of simultaneous electron energy-loss spectroscopy (EELS) and energy-dispersive X-ray spectroscopy (EDS) to scanning TEM tomography. Various tools, including refined tilt alignment procedures, multivariate statistical analysis and total-variation minimization enable the 3D reconstruction of analytical tomograms, providing 3D analytical metrics of materials science samples at the nanometer scale. This includes volumetric elemental maps, and reconstructions of EDS, low-loss and core-loss EELS spectra as four-dimensional spectrum volumes containing 3D local voxel spectra. From these spectra, compositional, 3D localized elemental analysis becomes possible opening the pathway to 3D nanoscale elemental quantification.
    Nanoscale 10/2014;
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    ABSTRACT: Single molecule studies using nanopores have gained attention due to the ability to sense single molecules in aqueous solution without the need to label them. In this study, short DNA molecules and proteins were detected with glass nanopores, whose sensitivity was enhanced by electron reshaping which decreased the nanopore diameter and created geometries with a reduced sensing length. Further, proteins having molecular weights (MW) ranging from 12 kDa to 480 kDa were detected, which showed that their corresponding current peak amplitude changes according to their MW. In the case of the 12 kDa ComEA protein, its DNA-binding properties to an 800 bp long DNA molecule was investigated. Moreover, the influence of the pH on the charge of the protein was demonstrated by showing a change in the translocation direction. This work emphasizes the wide spectrum of detectable molecules using nanopores from glass nanocapillaries, which stand out because of their inexpensive, lithography-free, and rapid manufacturing process.
    Nanoscale 10/2014;
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    ABSTRACT: Copper sulfide semiconductors made from earth-abundant elements have an optical absorption edge at ca. 1.2 eV, nearly ideal for solar energy harvesting. We report the growth and formation mechanism of vertically oriented arrays of copper sulfide nanostructures formed by electrochemical anodization. Key parameters that affect the morphology and phase of the nanostructures are type and strength of electrolyte, anodization voltage and duration. Cu2S and CuS nanostructures were obtained on both copper foil and copper-coated flexible Kapton substrates, and depending on the anodization parameters, consisted of vertically oriented arrays of nanowalls, nanoleafs or rods with branched nanodendrites. The anodization parameters also controlled the phase and stoichiometry of the nanostructures. p-type conduction for Cu2S nanostructures and n-type conduction for CuS nanostructures were revealed by admittance spectroscopy and Mott Schottky analysis. We also observed a weak, but nevertheless promising and previously unnoticed, photocatalytic action in copper sulfide nanorod and platelet arrays for the sunlight-driven conversion of CO2 into CH4. Under irradiation by AM 1.5G simulated sunlight at room temperature, a CH4 production rate as high as 38 μmol m(-2) h(-1) was obtained using the copper sulfide nanostructure arrays as stand-alone photocatalysts for CO2 photoreduction.
    Nanoscale 10/2014;
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    ABSTRACT: Porous carbon nitride nanosheets (PCNs) have been prepared for the first time by a simple liquid exfoliation method via probe sonication. These mesoporous nanosheets of around 5 nm in thickness combine several advantages including high surface area, enhanced light absorption and excellent water dispersity. It can be used as a versatile support for co-catalysts loading for photocatalytic dye degradation and water reduction. With 3.8 wt% Co3O4 loaded, PCNs can achieve more efficient photocatalytic degradation of Rhodamine B, compared with non-porous C3N4 nanosheets (CNs), bulk porous C3N4 (PCN) and bulk nonporous C3N4 (CN). With 1.0 wt% Pt loaded, CNs and PCN exhibit 7~8 times enhancement in H2 evolution than CN. Remarkably, PCNs with both porous and nanosheet-like features achieves 26 times higher activity in H2 evolution than CN. These significant improvements in photocatalytic activities can be attributed to the high surface area as well as better electron mobility of the two-dimensional nanostructure.
    Nanoscale 10/2014;
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    ABSTRACT: This manuscript describes a synthesis of nanocrystalline TiOF2 film. The nanocrystalline TiOF2 becomes chemically attached to the surface of the glass slide. These films are robust and can be recycled as photocatalysts for the degradation of organic dyes and solvents. These films also have significant antibacterial properties upon irradiation.
    Nanoscale 10/2014;
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    ABSTRACT: Fluorescent bio-imaging has received significant attention in a myriad of research disciplines, and QDs are playing an increasingly important role in these areas. Doped QDs, an important alternative to conventional heavy metal-containing QDs are employed for biomedical applications. However, since QDs are exogenous substances to the biological environment, the biocompatibility of QDs is expected to be challenging in some cases. Herein, nano fluorine-doped hydroxyapatite (FAp, a well-known biocompatible material) was introduced to endow biocompatibility to Cd-free Mn-doped ZnSe@ZnS QDs. Thus, a nano-FAp-QD conjugate was developed and the biocompatibility, as well as potential cell imaging application, was investigated. To construct the proposed conjugate, Cd-free highly luminescent Mn-doped ZnSe@ZnS QDs and monodispersed nano-FAp were first prepared in high-temperature organic media. For facilitating the conjugation, hydrophobic nano-FAp was made water soluble via o-phosphoethanolamine (PEA) coating, which further provides conjugating sites for QDs to anchor. Cytotoxicity studies indicated the developed conjugate indeed possesses good compatibility and low toxicity to cells. The nano-FAp-QDs conjugate was successfully employed for cancer cell staining for at least 24 h, demonstrating the potential usefulness of this material in future biomedical research.
    Nanoscale 10/2014;
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    ABSTRACT: In this study, we report the investigation of the influence of binary processing additives, 1,8-octanedithiol (ODT) and 1-chloronaphthalene (CN) on the performance of polymer solar cells (PSCs). It was found that the power conversion efficiency (PCE) can be enhanced to 8.55% from the PSCs processed with binary processing additives as compared with ∼6.50% from the PSCs processed with either ODT or CN processing additives. With binary processing additives, the crystallinity of the electron donor polymer, poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl][3-fluoro-2-[(2 ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]], was elevated, which in turn facilitated charge transport within the bulk heterojunction (BHJ) layer, resulting in a high short-circuit current and large fill factor. By photophysical studies, we further found that the high PCE is majorly attributed to the minimized nongeminate recombination by controlling the kinetic film morphologies of the BHJ composite by binary solvent processing additives.
    Nanoscale 10/2014;
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    ABSTRACT: We describe an innovative concept and facile approach in fabricating laterally assembled Ga2Te3/Te binary nanocomposite films, which comprise two-dimensional quasi-periodic Ga2Te3 nanoassemblies surrounded by interlocking highly-conductive Te single crystals for comprehensively establishing subnano- to micro-scaled multi-style versatile interfaces. The distinct Ga2Te3/Te nanocomposite film exhibits a power factor that is about 60 times higher than the reported conventional Ga2Te3 and Te materials, mainly due to the 2- to 3-order improved electrical conductivity and the comparable Seebeck coefficient.
    Nanoscale 10/2014;
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    ABSTRACT: We use in situ X-ray absorption and diffraction studies to directly monitor the crystallization of different titania polymorphs in one and the same solution. We find that, despite the commonly accepted polymorphic-crossover from anatase to rutile triggered by the critical size of nanoparticles, in the solution their respective nucleation and growth are independent processes. Moreover, we find that 5.9 nm rutile nanoparticles are formed prior to the formation of 8.4 nm anatase nanoparticles. Our results suggest that the origins of this crystallization mechanism lie in the formation of an intermediate non-crystalline phase and in time-dependent changes in the chemical environment.
    Nanoscale 10/2014;
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    ABSTRACT: Based upon the ambitious idea that one single particle could serve multiple purposes at the same time, the combination and simultaneous use of imaging and therapeutics has lately arisen as one of the most promising prospects among nanotechnologies directed toward biomedical applications. Intended for both therapeutics and diagnostics in vivo, highly complex nanostructures were specifically designed to simultaneously act as optical imaging probes and delivery vehicles. Yet, such multifunctional photonic nanoplatforms usually exploit fluorescence phenomena which require constant excitation light through biological tissues and thus significantly reduce the detection sensitivity due to the autofluorescence from living animals. In order to overcome this critical issue, the present article introduces a novel multifunctional agent based on persistent luminescence mesoporous nanoparticles. Being composed of a hybrid chromium-doped zinc gallate core/mesoporous silica shell architecture, we show that this nanotechnology can be used as an efficient doxorubicin-delivery vehicle presenting a higher cytotoxicity toward U87MG cells than its unloaded counterpart in vitro. In addition, we demonstrate that a persistent luminescence signal from these doxorubicin-loaded mesoporous nanophosphors opens a new way to highly sensitive detection in vivo, giving access to the real-time biodistribution of the carrier without any autofluorescence from the animal tissues. This new persistent luminescence-based hybrid nanotechnology can be easily applied to the delivery of any therapeutic agent, thus constituting a versatile and sensitive optical nanotool dedicated to both therapeutic and diagnostic applications in vivo.
    Nanoscale 10/2014;
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    ABSTRACT: Cobalt based catalysts are promising bifunctional electrocatalysts for both oxygen reduction and oxygen evolution reactions (ORR and OER) in unitized regenerative fuel cells (URFCs) operating with alkaline electrolytes. Here we report a hybrid composite of cobalt nanoparticles embedded in nitrogen-doped carbon (Co/N-C) via a solvothermal carbonization strategy. With the synergistic effect arised from the N-doped carbon and cobalt nanoparticles in the composite, the Co/N-C hybrid catalyst exhibits highly efficient bifunctional catalytic activity and excellent stability toward both ORR and OER. The ΔE (Oxygen electrode activity parameter for judging the overall electrocatalytic activity of a bifunctional electrocatalyst) value for Co/N-C is 0.859 V, which is smaller than Pt/C and most of the non-precious metal catalysts in previous literatures. Furthermore, the Co/N-C composite also shows better bifunctional catalytic activity than its oxidative counterparts, which could be attributed to the high specific surface area and efficient charge transfer ability of the composite, as well as the good synergistic effect between N-doped carbon and the Co nanoparticles in the Co/N-C composite.
    Nanoscale 10/2014;
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    ABSTRACT: The crystal structure of selenolate-capped Au25(SePh)18− nanoclusters has been unambiguously determined for the first time, and provides a solid basis for a deeper understanding of the structure–property relationships. The selenolate-capped Au25 cluster shows noticeable differences from the previously reported Au25(SCH2CH2Ph)18− counterpart, albeit both share the icosahedral Au13 core and semi-ring Au2(SeR)3 or Au2(SR)3 motifs. Distinct differences in the electronic structure and optical, catalytic and electrochemical properties are revealed by the coupling experiments with density functional theory (TD-DFT) calculations. Overall, the successful determination of the Au25(SePh)18− structure removes any ambiguity about its structure, and comparison with the thiolated Au25 counterpart helps us to further understand how the ligands affect the properties of the nanocluster.
    Nanoscale 10/2014;
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    ABSTRACT: Single gold particles may serve as room temperature single electron memory units due to their size dependent electronic level spacing. Here we present a proof of concept study by electrochemically controlled scanning probe experiments performed on tailor-made Au particles of narrow dispersity. In particular the charge transport characteristics through chemically synthesized hexane-1-thiol and 4-pyridylbenzene-1-thiol mixed monolayer protected Au144 clusters (MPCs) by differential pulse voltammetry (DPV) and electrochemical scanning tunneling spectroscopy (EC-STS) are reported. The pyridyl groups exposed by the Au-MPCs enable their immobilization on Pt(111) substrates. By varying the humidity during their deposition, samples coated by stacks of compact monolayers of Au-MPCs or decorated with individual, laterally separated Au-MPCs are obtained. DPV experiments with stacked monolayers of Au144-MPCs and EC-STS experiments with laterally separated individual Au144-MPCs are performed both in aqueous and ionic liquid electrolytes. Lower capacitance values were observed for individual clusters compared to ensemble clusters. This trend remains the same irrespective of the composition of the electrolyte surrounding to the Au144-MPC. The resolution of the energy level spacing of single clusters however, is strongly affected by the proximity of neighboring particles.
    Nanoscale 10/2014;
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    ABSTRACT: Up till now, almost all of the porous Pd nanostructures were either polycrystalline formed by aggregation of small nanostructures or single-crystalline structure with lower catalytic active {111} facets dominated rooted in the thermodynamic control growth process. In this study, we present a first report on the preparation of porous, high catalytic active {100} facets dominated, and single-crystalline Pd nanoflowers (PSNFs) that show highly improved catalytic performances. PSNFs was synthesized by a mild and controllable Pd nanocube seed-mediated growth strategy, in which Br¯ of CTAB works as capping agent, O2/Cl¯ works as etching pair, and the gradient of local precursor concentration controls the balance of kinetics. Thanks to the specific structure, PSNFs exhibited enhanced ethanol oxidation activity, ultrahigh anti-poisoning and stability. The mechanism of the Pd PSNFs formation was proposed based on the study of time-dependent morphological evolution process.
    Nanoscale 10/2014;
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    ABSTRACT: Self-assembly of cyclic peptide nanotubes (CPNs) in polymer thin films has opened up the possibility to create separation membranes with tunable nanopores that can differentiate molecules at the sub-nanometer level. While it has been demonstrated that the interior chemistry of the CPNs can be tailored by inserting functional groups in the nanopore lumen (mCPNs), a design strategy for picking the chemical modifications that lead to particular transport properties has not been established. Drawing from the knowledgebase of functional groups in natural amino acids, here we use molecular dynamics simulations to elucidate how bioinspired mutations influence the transport of water through mCPNs. We show that, at the nanoscale, factors beside the pore size, such as electrostatics interactions and steric effects, can dramatically change the transport properties. We recognize a novel asymmetric structure of water under nanoconfinement inside the chemically functionalized nanotubes and identify that small non-polar Glycine-mimic groups that minimize the steric constraints and confer a hydrophobic character to the nanotube interior are the fastest transporters of water. Our computational thought experiments on a realistic material concept circumvents synthetic challenges, and lay the foundation for bioinspired principles to tailor artificial nanochannels for separation applications such as desalination, ion-exchange and carbon capture.
    Nanoscale 10/2014;
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    ABSTRACT: One of the main barriers blocking sustainable hydrogen production is the use of expensive platinum-based catalysts to produce hydrogen from water. Herein we report the cost-effective synthesis of catalytically active, nitrogen-doped, cobalt-encased carbon nanotubes using inexpensive starting materials—urea and cobalt chloride hexahydrate (CoCl2•6H2O). Moreover, we show that the as-obtained nanocarbon material exhibits a remarkable electrocatalytic activity toward hydrogen evolution reaction (HER); and thus it can be deemed as a potential alternative to noble metal HER catalysts. In particular, the urea-derived carbon nanotubes synthesized at 900 °C (denoted as U-CNT-900) shows a superior catalytic activity for HER with low overpotential and high current density in our study. Notably also, U-CNT-900 has the ability to operate stably at all pH values (pH 0-14), and even in buffered seawater (pH 7). The possible synergistic effects between carbon-coated cobalt nanoparticles and the nitrogen dopants can be proposed to account for the HER catalytic activity of U-CNT-900. Given the high natural abundance, ease of synthesis, and high catalytic activity and durability in in seawater, this U-CNT-900 material is promising for hydrogen production from water in industral application.
    Nanoscale 10/2014;
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    ABSTRACT: In this paper, we reported the structural evolution of Bi4.2K0.8Fe2O9+δ nanobelts to BiFeO3 nanochains and the related variations of multiferroic properties. By using in-situ transmission electron microscopy with comprehensive characterization, it was found that the layered perovskite multiferroic Bi4.2K0.8Fe2O9+δ nanobelts were very unstable in a vacuum environment with Bi being easily removed. Based on this finding, a simple vacuum annealing method was designed which successfully transformed the Bi4.2K0.8Fe2O9+δ nanobelts into one-dimensional BiFeO3 nanochains. Both the Bi4.2K0.8Fe2O9+δ nanobelts and the BiFeO3 nanochains showed multiferroic behaviors, with their ferroelectric and ferromagnetic properties clearly established by piezoresponse and magnetic measurements, respectively. Interestingly, the BiFeO3 nanochains had a larger magnetization than the Bi4.2K0.8Fe2O9+δ nanobelts. Moreover, the BiFeO3 nanochains exhibited a surprisingly large exchange bias with small training effects. This one-dimensional BiFeO3 multiferroic nanostructure characterized by a relatively stable exchange bias offers important functionalities that may be attractive for device applications.
    Nanoscale 10/2014;
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    ABSTRACT: The catalytic role of germanium (Ge) was investigated to improve the electrochemical performance of tin dioxide grown on graphene (SnO2/G) nanocomposites as an anode material of lithium ion batteries (LIBs). Germanium dioxide (GeO2) and SnO2 nanoparticles (<10 nm) were uniformly anchored on the graphene sheets via a simple single-step hydrothermal method. The synthesized SnO2(GeO2)0.13/G nanocomposites can deliver a capacity of 1200 mAh/g at a current density of 100 mA/g, which is much higher than the traditional theoretical specific capacity of such nanocomposites (~702 mAh/g). More importantly, the SnO2(GeO2)0.13/G nanocomposites exhibited improved rate and large current capability (885 mAh/g at a discharge current of 2000 mA/g) and excellent long cycling stability (almost 100% retention after 600 cycles). The enhanced electrochemical performance was attributed to the catalytic effect of Ge which enabled the reversible reaction of metals (Sn and Ge) to metals oxide (SnO2 and GeO2) during the charge/discharge processes. Our demonstrated approach towards nanocomposite catalyst engineering opens new avenues for next-generation high-performance rechargeable Li-ion batteries anode materials.
    Nanoscale 10/2014;
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    ABSTRACT: The synthesis of layered transition-metal-disulfide (MS2, M = Mo, W) nanosheets with layer controllability and large-area uniformity is an essential requirement for their application in electronic and optical devices. In this report, we describe a synthesis process of WS2 nanosheets with layer controllability and high uniformity using chemical vapor deposition (CVD) and WCl6 and H2S as gas-phase precursors. Through this process, we can systematically modulate the thickness of WS2 nanosheets by controlling the duration of the reaction between WCl6 and H2S. The CVD-grown WS2 nanosheets exhibit good stoichiometry as well as dependencies of a clear Raman shift and bandgap on the number of layers. These properties are confirmed by X-ray photoemission spectroscopy, Raman spectroscopy, and photoluminescence measurements. The number of layers of WS2 nanosheets is confirmed by atomic force microscopy. Finally, we demonstrate the fabrication and performance of a photodetector based on a hybrid structure consisting of graphene and a WS2 nanosheet
    Nanoscale 10/2014;