pinecone/core-2020-05-10-deduplication huggingface dataset:
Oxygen Reduction Reaction Promotes Li+ Desorption from Cathode Surface in Li-O2 Batteries

Li-O2 batteries are claimed to be one of the future energy storage technologies. Great number of scientific and technological challenges should be solved first to transform Li-O2 battery from a promise to real practical devices. Proposed mechanisms for oxygen reduction assume a reservoir of solved Li+ ions in the electrolyte. However, the role that adsorbed Li+ on the electrode surface might have on the overall oxygen reduction reaction (ORR) has not deserved much attention. Adsorbed Li+ consumption is monitored here using impedance measurements from extended electrochemical double layer capacitance, which depends on the carbon matrix surface area. The presence of O2 drastically reduces the amount of adsorbed Li+, signaling the kinetic competition between Li+ surface adsorption and its consumption, only for potentials corresponding to the oxygen reduction reaction. Noticeably double layer capacitance remains unaltered after cycling. This fact suggests that the ORR products (Li2O2 and Li2CO3) are not covering the internal electrode surface, but deposited on the outer electrode-contact interface, hindering thereby the subsequent reaction. Current results show new insights into the discharge mechanism of Li-O2 batteries and reveal the evidence of Li+ desorption from the C surface when the ORR starts.We thank financial support from Generalitat Valenciana (ISIC/ 2012/008 Institute of
Nanotechnologies for Clean Energies). The authors acknowledge Dr. Conchi Ania from
National Institute of Carbon for providing PSCo and AG carbons and their
characterization
Fabrication of MoS2 nanowire arrays and layered structures via the self-assembly of block copolymers

The electronics industry is beginning to show interest in 2D molybdenum disulfide (2D‐MoS2) as a potential device material due to its low band gap and high mobility. However, current methods for its synthesis are not “fab” friendly and require harsh environments and processes. Here, a novel method to prepare MoS2 nanowire arrays and layered structures via self‐assembly of a block copolymer system is reported. Well‐controlled films of microphase separated line‐space nanopatterns have been achieved by solvent annealing process. The self‐assembled films are used as “templates” for the generation of nonstoichometric molybdenum oxide by in situ inclusion technique following UV/Ozone treatment. Well‐ordered array of MoS2 and a layered structure are then prepared by chemical vapor deposition using sulfur powder at lower temperature. The surface morphology, crystal structure, and phases are examined by different microscopic and spectroscopic techniques. This strategy can be extended to several other 2D materials systems and open the pathway toward better optoelectronic and nanoelectromechanical systems
Interface-Coupled BiFeO3/BiMnO3 Superlattices with Magnetic Transition Temperature up to 410 K

This research was funded by the Engineering and Physical Sciences Research Council, (EP/P50385X/1), the European Research Council (ERC-2009-AdG 247276 NOVOX). The work at Texas A&M was funded by the U.S. National Science Foundation (DMR-1401266). The work at Los Alamos was supported by the U.S. Department of Energy through the LANL/LDRD program and was performed, in part, at the Center for Integrated Nanotechnologies, a U.S. Department of Energy, Office of Basic Energy Sciences user facility.  Use of the National Synchrotron Light Source, Brookhaven National Laboratory, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-98CH10886.This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1002/admi.20150059
Improving Charge Separation across a Hybrid Oxide/Polymer Interface by Cs Doping of the Metal Oxide

The process of photoinduced charge carrier separation in hybrid optoelectronics remains only partially understood, with the mechanism behind creation and dissociation of bound charge pairs (BCPs) being open questions. To investigate these processes, we employ the model hybrid ZnO/P3HT system and show that Cs doping of ZnO results in a decrease in the density of gap states at the metal oxide surface and in turn, a reduction in the yield of BCPs. This provides direct experimental evidence for a previously proposed model of BCP creation by electron trapping at the metal oxide surface states. Furthermore, Cs doping is found to substantially increase open circuit voltage in these devices without the negative effects on short circuit current that were observed in studies with other dopants. This offers new possibilities for hybrid photovoltaic devices with increased power conversion efficiencies and provides valuable insights on the charge separation processes in hybrid organic-inorganic photovoltaics.We kindly thank Prof. Annemarie Pucci and Prof. Uwe Bunz for providing access to the AFM and the device fabrication facilities, respectively. A. A. B.  is a Royal Society University Research Fellow. P. E. H. and Y. V. thank the Excellence Initiative for funding.This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/admi.20150061
Robust nanostructured silver and copper fabrics with localized surface plasmon resonance property for effective visible light induced reductive catalysis

Inspired by high porosity, absorbency, wettability and hierarchical ordering on the micrometer and nanometer scale of cotton fabrics, a facile strategy is developed to coat visible light active metal nanostructures of copper and silver on cotton fabric substrates. The fabrication of nanostructured Ag and Cu onto interwoven threads of a cotton fabric by electroless deposition creates metal nanostructures that show a localized surface plasmon resonance (LSPR) effect. The micro/nanoscale hierarchical ordering of the cotton fabrics allows access to catalytically active sites to participate in heterogeneous catalysis with high efficiency. The ability of metals to absorb visible light through LSPR further enhances the catalytic reaction rates under photoexcitation conditions. Understanding  the mode of electron transfer during visible light illumination in Ag@Cotton and Cu@Cotton through electrochemical measurements provides mechanistic evidence on the influence of light in promoting electron transfer during heterogeneous catalysis for the first time. The outcomes presented in this work will be helpful in designing new multifunctional fabrics with the ability to absorb visible light and thereby enhance light-activated catalytic processes
Controlled Sulfurization Process for the Synthesis of Large Area MoS2 Films and MoS2/WS2 Heterostructures

Large area MoS2 films with tunable physical-chemical properties are grown on dielectric substrates by annealing of ultrathin Mo layers in the presence of a sulfur-containing gaseous precursor. Different growth conditions are found to have a significant impact on material properties, including chemical composition, roughness, and grain sizes, thus shedding light on critical parameters that govern sulfurization processes for the synthesis of large area 2D transition metal dichalcogenides. Optimized growth conditions in combination with the use of single crystal sapphire substrates with atomically flat interface result in the formation of oriented MoS2 films with improved quality and electrical performance. On the basis of this versatile synthesis technique, an original double-step process is presented for the synthesis of WS2/MoS2 vertical heterostructures. Good uniformity of layers over large area has enabled first isolation of defects by electron spin resonance spectroscopy with densities correlated with mobility degradation and the first experimental characterization of the band alignment at the interfaces of MoS2, WS2, and their vertical stacks with the underlying SiO2 insulator.status: publishe
Biomimetic locomotion on water of a porous natural polymeric composite

This is the pre-peer reviewed version of the following article: Biomimetic Locomotion on Water of a Porous Natural Polymeric Composite. Advanced Materials Interfaces, 3 (11), DOI: 10.1002/admi.201500854, which has been published in final form at http://dx.doi.org/10.1002/admi.201500854. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Observation of the natural world can provide invaluable information on the mechanisms that semiaquatic living organisms or bacteria use for their self-propulsion. Microvelia, for example, uses wax excreted from its legs to move on water in order to escape from predators or reach the bank of the river. Mimicking such mechanism, few self-propelled materials on water, as camphor, have been previously developed, but weak points like slow locomotion, short movement duration or shape-restrictions still\ud
need to be improved. Herein we present a totally green self-assembled porous system, formed by the combination of a natural polymer with an essential oil, that spontaneously moves on water for hours\ud
upon expulsion of the oil, with high velocities reaching 15 cm/s. The structural characteristics of the natural polymeric composite are carefully analyzed and associated to its spontaneous movement. Surface tension change experiments are also presented that connect the essential oil release with the locomotion of the porous composite films. This research work opens novel routes towards bio-inspired\ud
natural materials that can be used for mimicking and studying the motion of bio-organisms and microorganisms, and for applications such as energy harvesting, aquatic pollution monitoring, drug delivery, to name few
Amorphous Alumina Barrier Coatings on Glass: MOCVD Process and Hydrothermal Ageing

Amorphous alumina coatings are applied on the inner surface of glass containers aiming at improving their hydrothermal ageing barrier properties. A direct liquid injection technology is implemented in a metal-organic chemical vapor deposition (MOCVD) process to feed the reactor in a controlled and reproducible way with a solution of aluminum tri-isopropoxide (ATI) in anhydrous cyclohexane. Amorphous alumina coatings are characterized by X-ray diffraction, electron probe microanalysis, scanning electron microscopy, atomic force microscopy and scratch-test method. They are amorphous and hydroxylated at process temperatures between 360 and 420 °C and close to Al 2 O 3 stoichiometry between 490 and 560 °C. Hydrothermal ageing simulated by a standard sterilization cycle results in the increase of the root mean square of the surface of the coatings from ≈17 to 61 nm and in the increase of the porosity without affecting the adhesion of the coatings on the glass substrates
High On/Off ratio memristive switching of manganite/cuprate bilayer by interfacial magnetoelectricity

Memristive switching serves as the basis for a new generation of electronic devices. Memristors are two-terminal devices in which the current is turned on and off by redistributing point defects, e.g., vacancies, which is difficult to control. Memristors based on alternative mechanisms have been explored, but achieving both the high On/Off ratio and the low switching energy desirable for use in electronics remains a challenge. Here we report memristive switching in a La_(0.7)Ca_(0.3)MnO_(3)/PrBa_(2)Cu_(3)O_(7) bilayer with an On/Off ratio greater than 103 and demonstrate that the phenomenon originates from a new type of interfacial magnetoelectricity. Using results from firstprinciples calculations, we show that an external electric-field induces subtle displacements of the interfacial Mn ions, which switches on/off an interfacial magnetic “dead” layer, resulting in memristive behavior for spin-polarized electron transport across the bilayer. The interfacial nature of the switching entails low energy cost about of a tenth of atto Joule for write/erase a “bit”. Our results indicate new opportunities for manganite/cuprate systems and other transition-metal-oxide junctions in memristive applications
Membrane tubulation by elongated and patchy nanoparticles

Advances in nanotechnology lead to an increasing interest in how
nanoparticles interact with biomembranes. Nanoparticles are wrapped
spontaneously by biomembranes if the adhesive interactions between the
particles and membranes compensate for the cost of membrane bending. In the
last years, the cooperative wrapping of spherical nanoparticles in membrane
tubules has been observed in experiments and simulations. For spherical
nanoparticles, the stability of the particle-filled membrane tubules strongly
depends on the range of the adhesive particle-membrane interactions. In this
article, we show via modeling and energy minimization that elongated and patchy
particles are wrapped cooperatively in membrane tubules that are highly stable
for all ranges of the particle-membrane interactions, compared to individual
wrapping of the particles. The cooperative wrapping of linear chains of
elongated or patchy particles in membrane tubules may thus provide an efficient
route to induce membrane tubulation, or to store such particles in membranes.Comment: 11 pages, 6 figure
Toward robust segmented nanowires : understanding the impact of crystallographic texture on the quality of segment interfaces in magnetic metallic nanowires

Segmented nanowires (NWs) have found a wealth of applications due to their multifuctionality, arising from complementarities and synergies among segments of different materials. However, to ensure a practical use of segmented NWs, high quality interfaces between dissimilar segments must be ensured. Herein, tri-segmented CoPt/Cu/Ni NWs and bi-segmented CoPt/Ni magnetic NWs are fabricated by means of template-assisted electrodeposition and the characteristics of their interfaces are investigated in detail. The presence of a Cu segment sandwiched between the CoPt and the Ni segments severely affects the integrity of the whole NW. Namely, Cu deposits in a (200) textured face-centered cubic (fcc) structure, which cannot accommodate well on the c-axis oriented hexagonal close-packed CoPt. Instead, when the Cu segment is absent, well-connected CoPt/Ni NWs with smooth interface are obtained. Unlike the Cu segment, Ni shows the (111) textured fcc structure, which holds good crystallographic matching with the underlying CoPt segment. Magnetic measurements reveal that CoPt/Ni NWs exhibit staircase-like hysteresis loops similar to the tri-segmented CoPt/Cu/Ni NWs. Such loop shape stems from the dissimilar coercivity between the hard (CoPt) and soft (Ni) segments. The bi-segmented NWs (with robust interfaces) are appealing for multi-bit recording media, magnetic nanoelectromechanical systems and magnetically-driven wireless drug delivery nanoplatforms
Disentangling Epitaxial Growth Mechanisms of Solution Derived Functional Oxide Thin Films

Altres ajuts: CSIC E-08-2012-1321248 i E-08-2013-1028356This study investigates the mechanisms of epitaxial development and functional properties of oxide thin films (CeZrO , LaNiO, and BaSrTiO) grown on single crystal substrates (YO:ZrO, LaAlO, and SrTiO) by the chemical solution deposition approach. Rapid thermal annealing furnaces are very powerful tools in this study providing valuable information of the early stages of nucleation, the kinetics of epitaxial film growth, and the coarsening of nanocrystalline phases. Advanced transmission electron microscopies, X-ray diffraction, and atomic force microscopy are employed to investigate the film microstructure and morphology, microstrain relaxation, and epitaxial crystallization. This study demonstrates that the isothermal evolution toward epitaxial film growth follows a self-limited process driven by atomic diffusion, and surface and interface energy minimization. All investigated oxides experience a transformation from the polycrystalline to the epitaxial phase. This study unequivocally evidences that the film thickness highly influences the epitaxial crystallization rate due to the competition between heterogeneous and homogeneous nucleation barriers and the fast coarsening of polycrystalline grains as compared to epitaxial growth. The investigated films possess good functional properties, and this study successfully confirms an improvement at long annealing times that can be correlated with grain boundary healing processes. Thick epitaxial films can be crystallized by growing sequential individual epitaxial layers
Solution processable metal oxide thin film deposition and material growth for electronic and photonic devices

A comprehensive review of recent advances in solution processing and growth of metal-oxide thin films for electronic and photonic devices is presented, with specific focus on precise solution-based technological coatings for electronics and optics, and new concepts for oxide material growth for electrochemical, catalytic, energy storage and conversion systems, information technology, semiconductor device processing and related devices. Throughout, the nature of the soluble precursors solutions and their relationship to film formation process by various solution coating techniques are collated and compared, highlighting advantages in precursor design for creating complex oxides for devices. Because of the versatility of solution-processable oxides and functional material coating, it is important to capture the advances made in oxide deposition for plastic electronics, see-through and wearable devices, and high-fidelity thin film transistors on curved or flexible displays. Solution processing, even for oxides, allows control over composition, thickness, optical constants, porosity, doping, tunable optical absorbance/transmission, band structure engineering, 3D-substrate coating, complex composite oxide formation and multi-layered oxide systems that are more difficult to achieve using chemical vapor deposition (CVD) or atomic layer deposition (ALD) processes. We also discuss limitations of solution processing for some technologies and comment on the future of solution-based processing of metal-oxide materials for electronics, photonics and other technologies
Combined Macro/Nanoscale Investigation of the Chemical Vapor Deposition of Fe from Fe(CO)5

Experiments and computations are performed to model the chemical vapor deposition of iron (Fe) from iron pentacarbonyl (Fe(CO)5). The behavior of the deposition rate is investigated as a function of temperature, in the range 130–250 °C, and pressure in the range 10–40 Torr. Furthermore, the evolution of the surface roughness is correlated with the deposition temperature. By combining previously published mechanisms for the decomposition of Fe(CO)5, a predictive 3D macroscale model of the process is built. Additionally, a nanoscale and a multiscale framework are developed for linking the evolution of the surface of the film with the operating conditions at the reactor scale. The theoretical predictions from the coupled macro/nanoscale models are in very good agreement with experimental measurements indicating poisoning of the surface from carbon monoxide and decrease of the film roughness when temperature increases
Nanocone decorated ZnO microspheres exposing the (0001) plane and enhanced photocatalytic properties

WZ thanks EPSRC for a platform grant (No. EP/K015540/1) and financial support to the Electron Microscopy Laboratory (No. EP/F019580/1)ZnO spherical particles exposing only the (0001) planes were prepared by an established solvothermal method using a water‒ethylene glycol (EG) mix as a solvent. It was found that poorly crystalline nanoparticles formed first, followed by their aggregation into microspheres consisting of crystallites embedded in ethylene glycol and precursor molecules/ions. The grown up nanocrystallites and nanocones in the microspheres are all radially aligned. The possible formation mechanisms, in particular, the roles of water molecules, ethylene glycol and the intrinsic dipolar field of ZnO crystals, are discussed. X-ray photoelecton spectroscopy (XPS) experiments indicated the spherical particles were terminated solely by zinc atoms. Brunauer-Emmett-Teller (BET) measurements in conjunction with the degradation of methylene blue (MB) dye data demonstrated that the photocatalytic performance of the ZnO spheres depended on the growth time and was significantly improved compared to traditional ZnO nanorods. This study is a rare example which combines nanostructural characterisation of ZnO particles terminated with a single (0001) plane of known Zn2+-polarity with their photocatalytic performance.PostprintPeer reviewe
Solution Monolayer Epitaxy for Tunable Atomically Sharp Oxide Interfaces

Epitaxial growth of atomically-sharp interfaces serves as one of the main
building blocks of nanofabrication. Such interfaces are crucial for the
operation of various devices including transistors, photo-voltaic cells, and
memory components. In order to avoid charge traps that may hamper the operation
of such devices, it is critical for the layers to be atomically-sharp.
Fabrication of atomically sharp interfaces normally requires ultra-high vacuum
techniques and high substrate temperatures. We present here a new self-limiting
wet chemical process for deposition of epitaxial layers from alkoxide
precursors. This method is fast, cheap, and yields perfect interfaces as we
validate by various analysis techniques. It allows the design of
heterostructures with half-unit cell resolution. We demonstrate our method by
designing hole-type oxide interfaces SrTiO3/BaO/LaAlO3. We show that transport
through this interface exhibits properties of mixed electron-hole contributions
with hole mobility exceeding that of electrons. Our method and results are an
important step forward towards a controllable design of a p-type oxide
interface.Comment: 5 figures 5 page
X-ray radiography to visualize the rebar-cementitious matrix interface and judge the delay in corrosion through self-repair by encapsulated polyurethane

Corrosion of steel reinforcement is one of the most detrimental attack mechanisms for reinforced concrete structures. The presence of cracks, which are inextricably linked to reinforced concrete, accelerates this attack mechanism. The aim of this study is to heal cracks by an autonomous mechanism, which is triggered upon crack appearance. With an accelerated corrosion test on mortar samples with embedded reinforcement bars, it is shown that the presence of cracks indeed accelerates the onset and propagation of corrosion at the interface between the rebar and the cementitious matrix. Moreover, it is shown that crack healing in both the traditional, manual way and the proposed autonomous way, with an encapsulated one-component polyurethane, delays the onset and propagation of corrosion. The difference in corrosion behavior is proven by visual evaluation of the rebar surface and by X-ray radiographic analysis, which is proposed as a successful technique to evaluate the crack healing efficiency and more specifically the potential to delay corrosion
A rapid, low-cost, and scalable technique for printing state-of-the-art organic field-effcet transistors

In the last few years exciting advances have been achieved in developing printing techniques for organic semiconductors, and impressive mobility values have been reported for the resulting organic field-effect transistors (OFETs). However, not all these techniques are scalable and some of them require additional crystallization steps. This study reports on the fabrication of OFETs employing blends of four benchmark organic semiconductors with polystyrene and demonstrates that applying the same formulation and experimental conditions for printing them, highly reproducible and uniform crystalline films exhibiting high OFET performance are successfully achieved. It is noted that the mobility values achieved here are not the highest reported for the studied materials; however, they are state-of-the-art values and could be regarded as exceptional considering the low cost and fast speed of the fabrication process involved here.Peer ReviewedPostprint (published version