|
“Approaching the limits of cationic and anionic electrochemical activity with the Li-rich layered rocksalt Li3IrO4”. Perez AJ, Jacquet Q, Batuk D, Iadecola A, Saubanere M, Rousse G, Larcher D, Vezin H, Doublet M-L, Tarascon J-M, Nature energy 2, 954 (2017). http://doi.org/10.1038/S41560-017-0042-7
Abstract: The Li-rich rocksalt oxides Li2MO3 (M = 3d/4d/5d transition metal) are promising positive-electrode materials for Li-ion batteries, displaying capacities exceeding 300 mAh g(-1) thanks to the participation of the oxygen non-bonding O(2p) orbitals in the redox process. Understanding the oxygen redox limitations and the role of the O/M ratio is therefore crucial for the rational design of materials with improved electrochemical performances. Here we push oxygen redox to its limits with the discovery of a Li3IrO4 compound (O/M = 4) that can reversibly take up and release 3.5 electrons per Ir and possesses the highest capacity ever reported for any positive insertion electrode. By quantitatively monitoring the oxidation process, we demonstrate the material's instability against O-2 release on removal of all Li. Our results show that the O/M parameter delineates the boundary between the material's maximum capacity and its stability, hence providing valuable insights for further development of high-capacity materials.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Times cited: 55
DOI: 10.1038/S41560-017-0042-7
|
|
“A biogeometrical model for corolla fusion in Asclepiad flowers”. Gielis J, Caratelli D, Fougerolle Y, Ricci PE, Gerats T page 83 (2017).
Abstract: The molecular genetics of flower development have been studied extensively for more than two decades. Fusion of organs and the tendency to oligomery, important characteristics of flower evolution, so far have remained fairly elusive. We present a geometric model for shape and fusion in the corolla of Asclepiads. Examples demonstrate how fusion of petals creates stable centers, a prerequisite for the formation of complex pollination structures via congenital and postgenital fusion events, with the formation of de novo organs, specific to Asclepiads. The development of the corolla reduces to simple inequalities from the MATHS-BOX. The formation of stable centers and of bell and tubular shapes in flowers are immediate and logical consequences of the shape. Our model shows that any study on flowers, especially in evo-devo perspective should be performed within the wider framework of polymery and oligomery and of fusion and synorganization.
Keywords: H1 Book chapter; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.2991/978-94-6239-261-8_7
|
|
“A note about generalized forms of the Gielis formula”. Gielis J, Natalini P, Ricci PE page 107 (2017).
Abstract: We generalize the Gielis Superformula by extending the R. Chacon approach, but avoiding the use of Jacobi elliptic functions. The obtained results are extended to the three-dimensional case. Several new shapes are derived by using the computer algebra system Mathematica(C).
Keywords: H1 Book chapter; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.2991/978-94-6239-261-8_8
|
|
“On a geometric model of bodies with “complex” configuration and some movements”. Tavkhelidze I, Caratelli D, Gielis J, Ricci PE, Rogava M, Transirico M page 129 (2017).
Abstract: Aim of this chapter is analytical representation of one wide class of geometric figures (lines, surfaces and bodies) and their complicated displacements. The accurate estimation of physical characteristics (such as volume, surface area, length, or other specific parameters) relevant to human organs is of fundamental importance in medicine. One central idea of this article is, in this respect, to provide a general methodology for the evaluation, as a function of time, of the volume and center of gravity featured by moving of one class of bodies used of describe different human organs.
Keywords: H1 Book chapter; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.2991/978-94-6239-261-8_10
|
|
“Potential fields of self intersecting Gielis curves for modeling and generalized blending techniques”. Fougerolle Y, Truchetet F, Gielis J, Modeling In Mathematics 2, 67 (2017). http://doi.org/10.2991/978-94-6239-261-8_6
Abstract: The definition of Gielis curves allows for the representation of self intersecting curves. The analysis and the understanding of these representations is of major interest for the analytical representation of sectors bounded by multiple subsets of curves (or surfaces), as this occurs for instance in many natural objects. We present a construction scheme based on R-functions to build signed potential fields with guaranteed differential properties, such that their zero-set corresponds to the outer, the inner envelop, or combined subparts of the curve. Our framework is designed to allow for the definition of composed domains built upon Boolean operations between several distinct objects or some subpart of self-intersecting curves, but also provides a representation for soft blending techniques in which the traditional Boolean union and intersection become special cases of linear combinations between the objects' potential fields. Finally, by establishing a connection between R-functions and Lame curves, we can extend the domain of the p parameter within the R-p-function from the set of the even positive numbers to the real numbers strictly greater than 1, i.e. p is an element of]1, +infinity[.
Keywords: P1 Proceeding; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.2991/978-94-6239-261-8_6
|
|
“Visualizing redox orbitals and their potentials in advanced lithium-ion battery materials using high-resolution x-ray Compton scattering”. Hafiz H, Suzuki K, Barbiellini B, Orikasa Y, Callewaert V, Kaprzyk S, Itou M, Yamamoto K, Yamada R, Uchimoto Y, Sakurai Y, Sakurai H, Bansil A, Science Advances 3, e1700971 (2017). http://doi.org/10.1126/sciadv.1700971
Abstract: Reduction-oxidation (redox) reactions are the key processes that underlie the batteries powering smartphones, laptops, and electric cars. A redox process involves transfer of electrons between two species. For example, in a lithium-ion battery, current is generated when conduction electrons from the lithium anode are transferred to the redox orbitals of the cathode material. The ability to visualize or image the redox orbitals and how these orbitals evolve under lithiation and delithiation processes is thus of great fundamental and practical interest for understanding the workings of battery materials. We show that inelastic scattering spectroscopy using high-energy x-ray photons (Compton scattering) can yield faithful momentum space images of the redox orbitals by considering lithium iron phosphate (LiFePO4 or LFP) as an exemplar cathode battery material. Our analysis reveals a new link between voltage and the localization of transition metal 3d orbitals and provides insight into the puzzling mechanism of potential shift and how it is connected to the modification of the bond between the transition metal and oxygen atoms. Our study thus opens a novel spectroscopic pathway for improving the performance of battery materials.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Times cited: 9
DOI: 10.1126/sciadv.1700971
|
|
“Facile morphology-controlled synthesis of organolead iodide perovskite nanocrystals using binary capping agents”. Debroye E, Yuan H, Bladt E, Baekelant W, Van der Auweraer M, Hofkens J, Bals S, Roeffaers MBJ, ChemNanoMat : chemistry of nanomaterials for energy, biology and more 3, 223 (2017). http://doi.org/10.1002/CNMA.201700006
Abstract: Controlling the morphology of organolead halide perovskite crystals is crucial to a fundamental understanding of the materials and to tune their properties for device applications. Here, we report a facile solution-based method for morphology-controlled synthesis of rod-like and plate-like organolead halide perovskite nanocrystals using binary capping agents. The morphology control is likely due to an interplay between surface binding kinetics of the two capping agents at different crystal facets. By high-resolution scanning transmission electron microscopy, we show that the obtained nanocrystals are monocrystalline. Moreover, long photoluminescence decay times of the nanocrystals indicate long charge diffusion lengths and low trap/defect densities. Our results pave the way for large-scale solution synthesis of organolead halide perovskite nanocrystals with controlled morphology for future device applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 2.937
Times cited: 19
DOI: 10.1002/CNMA.201700006
|
|
“Tunable nitrogen-doped carbon nanoparticles from tannic acid and urea and their potential for sustainable soots”. Berthold T, Castro CR, Winter M, Hoerpel G, Kurttepeli M, Bals S, Antonietti M, Fechler N, ChemNanoMat : chemistry of nanomaterials for energy, biology and more 3, 311 (2017). http://doi.org/10.1002/CNMA.201700051
Abstract: Nano-sized nitrogen-doped carbon spheres are synthesized from two cheap, readily available and sustainable precursors: tannic acid and urea. In combination with a polymer structuring agent, nitrogen content, sphere size and the surface (up to 400 m(2)g(-1)) can be conveniently tuned by the precursor ratio, temperature and structuring agent content. Because the chosen precursors allow simple oven synthesis and avoid harsh conditions, this carbon nanosphere platform offers a more sustainable alternative to classical soots, for example, as printing pigments or conduction soots. The carbon spheres are demonstrated to be a promising as conductive carbon additive in anode materials for lithium ion batteries.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 2.937
Times cited: 14
DOI: 10.1002/CNMA.201700051
|
|
“Hybrid YBa2Cu3O7 superconducting-ferromagnetic nanocomposite thin films prepared from colloidal chemical solutions”. Bartolome E, Cayado P, Solano E, Mocuta C, Ricart S, Mundet B, Coll M, Gazquez J, Meledin A, Van Tendeloo G, Valvidares SM, Herrero-Martin J, Gargiani P, Pellegrin E, Magen C, Puig T, Obradors X, Advanced Electronic Materials 3, 1700037 (2017). http://doi.org/10.1002/AELM.201700037
Abstract: High T-c superconductor-ferromagnetic heterostructures constitute an appealing playground to study the interplay between flux vortices and magnetic moments. Here, the capability of a solution-derived route to grow hybrid YBa2Cu3O7-ferromagnetic nanocomposite epitaxial thin films from preformed spinel ferrite (MFe2O4, M = Mn, Co) nanoparticles (NPs) is explored. The characterization, performed using a combination of structural and magnetic techniques, reveals the complexity of the resulting nanocomposites. Results show that during the YBCO growth process, most of the NPs evolve to ferromagnetic double-perovskite (DP) phases (YBaCu2-x-yFexCoyO5/YBaCoFeO5), while a residual fraction of preformed ferrite NPs may remain in the YBCO matrix. Magnetometry cycles reflect the presence of ferromagnetic structures associated to the DPs embedded in the superconducting films. In addition, a superparamagnetic signal that may be associated with a diluted system of ferromagnetic clusters around complex defects has been detected, as previously observed in standard YBCO films and nanocomposites. The hybrid nanocomposites described in this work will allow studying several fundamental issues like the nucleation of superconductivity and the mechanisms of magnetic vortex pinning in superconducting/ferromagnetic heterostructures.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 4.193
Times cited: 7
DOI: 10.1002/AELM.201700037
|
|
“Gate induced monolayer behavior in twisted bilayer black phosphorus”. Sevik C, Wallbank JR, Gulseren O, Peeters FM, Çakir D, 2D materials 4, 035025 (2017). http://doi.org/10.1088/2053-1583/AA80C4
Abstract: Optical and electronic properties of black phosphorus strongly depend on the number of layers and type of stacking. Using first-principles calculations within the framework of density functional theory, we investigate the electronic properties of bilayer black phosphorus with an interlayer twist angle of 90 degrees. These calculations are complemented with a simple (k) over right arrow . (p) over right arrow model which is able to capture most of the low energy features and is valid for arbitrary twist angles. The electronic spectrum of 90 degrees twisted bilayer black phosphorus is found to be x-y isotropic in contrast to the monolayer. However x-y anisotropy, and a partial return to monolayer-like behavior, particularly in the valence band, can be induced by an external out-of-plane electric field. Moreover, the preferred hole effective mass can be rotated by 90 degrees simply by changing the direction of the applied electric field. In particular, a +0.4 (-0.4) V angstrom(1) out-of-plane electric field results in a similar to 60% increase in the hole effective mass along the y (x) axis and enhances the m(y)*/m(x)* (m(x)*/m(y)*) ratio as much as by a factor of 40. Our DFT and (k) over right arrow . (p) over right arrow simulations clearly indicate that the twist angle in combination with an appropriate gate voltage is a novel way to tune the electronic and optical properties of bilayer phosphorus and it gives us a new degree of freedom to engineer the properties of black phosphorus based devices.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 6.937
Times cited: 13
DOI: 10.1088/2053-1583/AA80C4
|
|
“The influence of branched alkyl side chains in A-D-A oligothiophenes on the photovoltaic performance and morphology of solution-processed bulk-heterojunction solar cells”. Ata I, Ben Dkhil S, Pfannmoeller M, Bals S, Duche D, Simon J-J, Koganezawa T, Yoshimoto N, Videlot-Ackermann C, Margeat O, Ackermann J, Baeuerle P, Organic chemistry frontiers : an international journal of organic chemistry 4, 1561 (2017). http://doi.org/10.1039/C7QO00222J
Abstract: Besides providing sufficient solubility, branched alkyl chains also affect the film-forming and packing properties of organic semiconductors. In order to avoid steric hindrance as it is present in wide-spread alkyl chains comprising a branching point position at the C2-position, i.e., 2-ethylhexyl, the branching point can be moved away from the pi-conjugated backbone. In this report, we study the influence of the modification of the branching point position from the C2-position in 2-hexyldecylamine (1) to the C4-position in 4-hexyldecylamine (2) connected to the central dithieno[3,2-b: 2', 3'-d] pyrrole (DTP) moiety in a well-studied A-D-A oligothiophene on the optoelectronic properties and photovoltaic performance in solution- processed bulk heterojunction solar cells (BHJSCs) with [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as the acceptor material. Post-treatment of the photoactive layers is performed via solvent vapor annealing (SVA) in order to improve the film microstructure of the bulk heterojunction. The time evolution of nanoscale morphological changes is followed by combining scanning transmission electron microscopy with low-energy-loss spectroscopic imaging (STEM-SI), solid-state absorption spectroscopy, and two-dimensional grazing incidence X-ray diffraction (2D-GIXRD). Our results show an improvement of the photovoltaic performance that is dependent on the branching point position in the donor oligomer. Optical spacers are utilized to increase light absorption inside the co-oligomer 2-based BHJSCs leading to increased power conversion efficiencies (PCEs) of 8.2% when compared to the corresponding co-oligomer 1-based devices. A STEM-SI analysis of the respective device cross-sections of active layers containing 1 and 2 as donor materials indeed reveals significant differences in their respective active layer morphologies.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.955
Times cited: 24
DOI: 10.1039/C7QO00222J
|
|
“Vapor Phase Fabrication of Nanoheterostructures Based on ZnO for Photoelectrochemical Water Splitting”. Barreca D, Carraro G, Gasparotto A, Maccato C, Altantzis T, Sada C, Kaunisto K, Ruoko T-P, Bals S, Advanced Materials Interfaces 4, 1700161 (2017). http://doi.org/10.1002/admi.201700161
Abstract: Nanoheterostructures based on metal oxide semiconductors have emerged
as promising materials for the conversion of sunlight into chemical energy.
In the present study, ZnO-based nanocomposites have been developed by
a hybrid vapor phase route, consisting in the chemical vapor deposition
of ZnO systems on fluorine-doped tin oxide substrates, followed by the
functionalization with Fe2O3 or WO3 via radio frequency-sputtering. The
target systems are subjected to thermal treatment in air both prior and after
sputtering, and their properties, including structure, chemical composition,
morphology, and optical absorption, are investigated by a variety of characterization
methods. The obtained results evidence the formation of highly
porous ZnO nanocrystal arrays, conformally covered by an ultrathin Fe2O3
or WO3 overlayer. Photocurrent density measurements for solar-triggered
water splitting reveal in both cases a performance improvement with respect
to bare zinc oxide, that is mainly traced back to an enhanced separation of
photogenerated charge carriers thanks to the intimate contact between the
two oxides. This achievement can be regarded as a valuable result in view of
future optimization of similar nanoheterostructured photoanodes.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.279
Times cited: 30
DOI: 10.1002/admi.201700161
|
|
“Thermal activated rotation of graphene flake on graphene”. Peymanirad F, Singh SK, Ghorbanfekr-Kalashami H, Novoselov KS, Peeters FM, Neek-Amal M, 2D materials 4, 025015 (2017). http://doi.org/10.1088/2053-1583/AA58A4
Abstract: The self rotation of a graphene flake over graphite is controlled by the size, initial misalignment and temperature. Using both ab initio calculations and molecular dynamics simulations, we investigate annealing effects on the self rotation of a graphene flake on a graphene substrate. The energy barriers for rotation and drift of a graphene flake over graphene is found to be smaller than 25 meV/atom which is comparable to thermal energy. We found that small flakes (of about similar to 4 nm) are more sensitive to temperature and initial misorientation angles than larger one (beyond 10 nm). The initial stacking configuration of the flake is found to be important for its dynamics and time evolution of misalignment. Large flakes, which are initially in the AA-or AB-stacking state with small misorientation angle, rotate and end up in the AB-stacking configuration. However small flakes can they stay in an incommensurate state specially when the initial misorientation angle is larger than 2 degrees. Our results are in agreement with recent experiments.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 6.937
Times cited: 16
DOI: 10.1088/2053-1583/AA58A4
|
|
“Short and long term effect of decreasing temperature on anammox activity and enrichment in mainstream granular sludge process”. De Cocker P, Bessiere Y, Hernandez-Raquet G, Dubos S, Mercade M, Sun XY, Mozo I, Barillon B, Gaval G, Caligaris M, Martin Ruel S, Vlaeminck SE, Sperandio M, 4, 50 (2017). http://doi.org/10.1007/978-3-319-58421-8_8
Abstract: This study investigates the impact of lower temperature on short term and long term (down to 10 degrees C) on a completely anoxic anammox granular sludge process. This is the first time granular sludge Anammox is operated in pure anoxic condition in SBR and at low temperature. Conversion performance, kinetic parameters, sludge characteristics and microbial community were analyzed.
Keywords: P1 Proceeding; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1007/978-3-319-58421-8_8
|
|
“Short and long term effect of decreasing temperature on anammox activity and enrichment in mainstream granular sludge process”. De Cocker P, Bessiere Y, Hernandez-Raquet G, Dubos S, Mercade M, Sun XY, Mozo I, Barillon B, Gaval G, Caligaris M, Ruel SM, Vlaeminck SE, Sperandio M, Frontiers In Wastewater Treatment And Modelling, Ficwtm 2017 4, 50 (2017). http://doi.org/10.1007/978-3-319-58421-8_8
Abstract: This study investigates the impact of lower temperature on short term and long term (down to 10 degrees C) on a completely anoxic anammox granular sludge process. This is the first time granular sludge Anammox is operated in pure anoxic condition in SBR and at low temperature. Conversion performance, kinetic parameters, sludge characteristics and microbial community were analyzed.
Keywords: P1 Proceeding; Sustainable Energy, Air and Water Technology (DuEL)
DOI: 10.1007/978-3-319-58421-8_8
|
|
“Direct synthesis of antimicrobial coatings based on tailored bi-elemental nanoparticles”. Benetti G, Cavaliere E, Canteri A, Landini G, Rossolini GM, Pallecchi L, Chiodi M, Van Bael MJ, Winckelmans N, Bals S, Gavioli L, APL materials 5, 036105 (2017). http://doi.org/10.1063/1.4978772
Abstract: Ultrathin coatings based on bi-elemental nanoparticles (NPs) are very promising to limit the surface-related spread of bacterial pathogens, particularly in nosocomial environments. However, tailoring the synthesis, composition, adhesion to substrate, and antimicrobial spectrum of the coating is an open challenge. Herein, we report on a radically new nanostructured coating, obtained by a one-step gas-phase deposition technique, and composed of bi-elemental Janus type Ag/Ti NPs. The NPs are characterized by a cluster-in-cluster mixing phase with metallic Ag nano-crystals embedded in amorphous TiO2 and present a promising antimicrobial activity including also multidrug resistant strains. We demonstrate the flexibility of the method to tune the embedded Ag nano-crystals dimension, the total relative composition of the coating, and the substrate type, opening the possibility of tailoring the dimension, composition, antimicrobial spectrum, and other physical/chemical properties of such multi-elemental systems. This work is expected to significantly spread the range of applications of NPs coatings, not only as an effective tool in the prevention of healthcare-associated infections but also in other technologically relevant fields like sensors or nano-/micro joining.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 4.335
Times cited: 21
DOI: 10.1063/1.4978772
|
|
“Large CO2 uptake on a monolayer of CaO”. Berdiyorov GR, Neek-Amal M, Hussein IA, Madjet ME, Peeters FM, Journal of materials chemistry A : materials for energy and sustainability 5, 2110 (2017). http://doi.org/10.1039/C6TA08810D
Abstract: Density functional theory calculations are used to study gas adsorption properties of a recently synthesized CaO monolayer, which is found to be thermodynamically stable in its buckled form. Due to its topology and strong interaction with the CO2 molecules, this material possesses a remarkably high CO2 uptake capacity (similar to 0.4 g CO2 per g adsorbent). The CaO + CO2 system shows excellent thermal stability (up to 1000 K). Moreover, the material is highly selective towards CO2 against other major greenhouse gases such as CH4 and N2O. These advantages make this material a very promising candidate for CO2 capture and storage applications.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 8.867
Times cited: 2
DOI: 10.1039/C6TA08810D
|
|
“Harvesting Renewable Energy for Carbon Dioxide Catalysis”. Navarrete A, Centi G, Bogaerts A, Mart?n?ngel, York A, Stefanidis GD, Energy technology 5, 796 (2017). http://doi.org/10.1002/ente.201600609
Abstract: The use of renewable energy (RE) to transform carbon dioxide into commodities (i.e., CO2 valorization) will pave the way towards a more sustainable economy in the coming years. But how can we efficiently use this energy (mostly available as electricity or solar light) to drive the necessary (catalytic) transformations? This paper presents a review of the technological advances in the transformation of carbon dioxide by means of RE. The socioeconomic implications and chemical basis of the transformation of carbon dioxide with RE are discussed. Then a general view of the use of RE to activate the (catalytic) transformations of carbon dioxide with microwaves, plasmas, and light is presented. The fundamental phenomena involved are introduced from a catalytic and reaction device perspective to present the advantages of this energy form as well as the inherent limitations of the present state-of-the-art. It is shown that efficient use of RE requires the redesign of current catalytic concepts. In this context, a new kind of reaction system, an energy-harvesting device, is proposed as a new conceptual approach for this endeavor. Finally, the challenges that lie ahead for the efficient and economical use of RE for carbon dioxide conversion are exposed.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 2.789
Times cited: 15
DOI: 10.1002/ente.201600609
|
|
“Time evolution studies of dithieno[3,2-b:2 ',3 '-d] pyrrole-based A-D-A oligothiophene bulk heterojunctions during solvent vapor annealing towards optimization of photocurrent generation”. Ben Dkhil S, Pfannmöller M, Ata I, Duche D, Gaceur M, Koganezawa T, Yoshimoto N, Simon J-J, Escoubas L, Videlot-Ackermann C, Margeat O, Bals S, Bauerle P, Ackermann J, Journal of materials chemistry A : materials for energy and sustainability 5, 1005 (2017). http://doi.org/10.1039/C6TA08175D
Abstract: Solvent vapor annealing (SVA) is one of the main techniques to improve the morphology of bulk heterojunction solar cells using oligomeric donors. In this report, we study time evolution of nanoscale morphological changes in bulk heterojunctions based on a well-studied dithienopyrrole-based A-D-A oligothiophene (dithieno[3,2-b: 2',3'-d] pyrrole named here 1) blended with [6,6]-phenyl-C-71-butyric acid methyl ester (PC71BM) to increase photocurrent density by combining scanning transmission electron microscopy and low-energy-loss spectroscopy. Our results show that SVA transforms the morphology of 1 : PC71BM blends by a three-stage mechanism: highly intermixed phases evolve into nanostructured bilayers that correspond to an optimal blend morphology. Additional SVA leads to completely phaseseparated micrometer-sized domains. Optical spacers were used to increase light absorption inside optimized 1 : PC71BM blends leading to solar cells of 7.74% efficiency but a moderate photocurrent density of 12.3 mA cm (-2). Quantum efficiency analyses reveal that photocurrent density is mainly limited by losses inside the donor phase. Indeed, optimized 1 : PC71BM blends consist of large donor-enriched domains not optimal for exciton to photocurrent conversion. Shorter SVA times lead to smaller domains; however they are embedded in large mixed phases suggesting that introduction of stronger molecular packing may help us to better balance phase separation and domain size enabling more efficient bulk heterojunction solar cells.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 8.867
Times cited: 19
DOI: 10.1039/C6TA08175D
|
|
“Vertically aligned diamond-graphite hybrid nanorod arrays with superior field electron emission properties”. Ramaneti R, Sankaran KJ, Korneychuk S, Yeh CJ, Degutis G, Leou KC, Verbeeck J, Van Bael MK, Lin IN, Haenen K, APL materials 5, 066102 (2017). http://doi.org/10.1063/1.4985107
Abstract: A “patterned-seeding technique” in combination with a “nanodiamond masked reactive ion etching process” is demonstrated for fabricating vertically aligned diamond-graphite hybrid (DGH) nanorod arrays. The DGH nanorod arrays possess superior field electron emission (FEE) behavior with a low turn-on field, long lifetime stability, and large field enhancement factor. Such an enhanced FEE is attributed to the nanocomposite nature of theDGHnanorods, which contain sp(2)-graphitic phases in the boundaries of nano-sized diamond grains. The simplicity in the nanorod fabrication process renders the DGH nanorods of greater potential for the applications as cathodes in field emission displays and microplasma display devices. (C) 2017 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 4.335
Times cited: 16
DOI: 10.1063/1.4985107
|
|
“Artificial orpiment, a new pigment in Rembrandt's palette”. van Loon A, Noble P, Krekeler A, van der Snickt G, Janssens K, Abe Y, Nakai I, Dik J, Heritage science 5, 26 (2017). http://doi.org/10.1186/S40494-017-0138-1
Abstract: This paper reports on how the application of macro X-ray fluorescence (MA-XRF) imaging, in combination with the re-examination of existing paint cross-sections, has led to the discovery of a new pigment in Rembrandt's palette: artificial orpiment. In the NWO Science4Arts 'ReVisRembrandt' project, novel chemical imaging techniques are being developed and applied to the study of Rembrandt's late paintings in order to help resolve outstanding questions and to gain a better understanding of his late enigmatic painting technique. One of the selected case studies is the Portrait of a Couple as Isaac and Rebecca, known as 'The Jewish Bride', dated c. 1665 and on view in the Rijksmuseum. During the re-installation of the Rijksmuseum in 2013, the picture was scanned using the Bruker M6 Jetstream MAXRF scanner. The resulting elemental distribution maps made it possible to distinguish many features in the painting, such as bone black remains of the original hat (P, Ca maps), and the now discolored smalt-rich background (Co, Ni, As, K maps). The arsenic (As) map also revealed areas of high-intensity in Isaac's sleeve and Rebecca's dress where it could be established that it was not related with the pigment smalt that also contains arsenic. This pointed to the presence of a yellow or orange arsenic-containing pigment, such as realgar or orpiment that is not associated with the artist's palette. Subsequent examination of existing paint cross-sections from these locations taken by Karin Groen in the 1990s identified isolated, almost perfectly round particles of arsenic sulfide. The round shape corresponds with published findings on a purified form of artificial orpiment glass obtained by dry processing, a sublimation reaction. In bright field, the particles characteristically exhibit a dark cross in the middle caused by internal light reflections. The results of additional non-invasive techniques (portable XRD and portable Raman) are discussed, as well as the implications of this finding and how it fits with Rembrandt's late experimental painting technique.
Keywords: A1 Journal article; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Times cited: 6
DOI: 10.1186/S40494-017-0138-1
|
|
“Jan Davidsz. de Heem (1606-1684): a technical examination of fruit and flower still lifes combining MA-XRF scanning, cross-section analysis and technical historical sources”. De Keyser N, van der Snickt G, Van Loon A, Legrand S, Wallert A, Janssens K, Heritage science 5, 38 (2017). http://doi.org/10.1186/S40494-017-0151-4
Abstract: This article discusses the technical examination of five flower and fruit still life paintings by the seventeenth century artist Jan Davidsz. de Heem (1606-1684). The painter is known for his meticulously composed and finely detailed still life paintings and is a master in imitating the surface textures of various fruits, flowers, and objects. Macro X-ray fluorescence (MA-XRF) scanning experiments were supplemented with a study of paint cross-sections and contemporary art technical sources with the aim of reconstructing the complex build-up of the overall lay-in of the composition and individual subjects. MA-XRF provided information on the distribution of key chemical elements present in painting materials and made it possible to recapture evidence of the different phases in the artist's working methods: from the application of the ground layers, to De Heem's characteristic oval-shaped underpaintings, and finally, the superposition of multiple paint layers in the working up of the paintings. SEM-EDX analysis of a limited number of paint cross-sections complemented the chemical images with local and layer-specific information on the microscale, providing more accuracy on the layer sequence and enabling the study of elements with a low atomic number for which the non-invasive technique is less sensitive. The results from this technical examination were in addition compared with recipes and paint instructions, to obtain a better understanding of the relation between the general practice and actual painting technique of Jan Davidsz. de Heem. Ultimately, this combined approach uncovered new information on De Heem's artistic practice and demonstrated the complementarity of the methods.
Keywords: A1 Journal article; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Times cited: 5
DOI: 10.1186/S40494-017-0151-4
|
|
“MA-XRF imaging on Rene Magritte's La condition humaine : insights into the artist's palette and technique and the discovery of a third quarter of La pose enchantee”. da Silva AT, Legrand S, van der Snickt G, Featherstone R, Janssens K, Bottinelli G, Heritage science 5, 37 (2017). http://doi.org/10.1186/S40494-017-0150-5
Abstract: Magritte's composition La condition humaine, 1935 was found to conceal under its paint layers an entire quarter of a lost composition by the artist, until recently only known from a small black/white catalogue illustration-La pose enchantee, 1927. This study is the latest contribution to the discovery of the artist's missing painting, now known to have been cut into four parts and re-used by Magritte as the support for new compositions. Non-destructive analytical and examination methods and specifically macroscopic X-ray fluorescence (MAXRF) scanning and conventional X-ray radiography (XRR) were the two non-destructive analytical and examination methods used to study both compositions and add to the existing knowledge on the artist's palette during both periods. The first method is capable of identifying the presence and the distribution of key chemical elements present in artists' materials. In some instances elemental mapping provided useful information on the hidden painting, but conventional X-ray radiography (XRR) enabled a better visualisation of the form and paint application of the underlying composition. Furthermore, the turnover edges of the canvas reveal after over 80 years the artist's palette directly to the viewer. Additional XRF scanning of this exposed paint has confirmed and added to the existing research published to date of this lost painting, including a proposed colour reconstruction, but at the same time highlighting the need for further analytical research involving both non-destructive point analysis and the use of paint samples.
Keywords: A1 Journal article; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Times cited: 7
DOI: 10.1186/S40494-017-0150-5
|
|
“Van Gogh's Irises and Roses : the contribution of chemical analyses and imaging to the assessment of color changes in the red lake pigments”. Centeno SA, Hale C, Caro F, Cesaratto A, Shibayama N, Delaney J, Dooley K, van der Snickt G, Janssens K, Stein SA, Heritage science 5, 18 (2017). http://doi.org/10.1186/S40494-017-0131-8
Abstract: Vincent van Gogh's still lifes Irises and Roses were investigated to shed light onto the degree to which the paintings had changed, both individually and in relation to each other since they were painted, particularly in regard to the fading of the red lakes. Non-invasive techniques, including macroscopic X-ray fluorescence mapping, reflectance imaging spectroscopy, and X-radiography, were combined with microanalytical techniques in a select number of samples. The in-depth microchemical analysis was necessary to overcome the complications that arise when evaluating by non-invasive methods alone the compositions of passages with complex layering and mixing of paints. The results obtained by these two approaches were complemented by color measurements performed on paint cross-sections and on protected edges, and with historical information provided by the artist's own descriptions, early reviews and reproductions, and the data was used to carry out digital color simulations that provided, to a certain extent, a visualization of how the paintings may have originally appeared.
Keywords: A1 Journal article; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Times cited: 21
DOI: 10.1186/S40494-017-0131-8
|
|
“The young Van Dyck's fingerprint : a technical approach to assess the authenticity of a disputed painting”. Harth A, van der Snickt G, Schalm O, Janssens K, Blanckaert G, Heritage science 5, 22 (2017). http://doi.org/10.1186/S40494-017-0136-3
Abstract: The painting Saint Jerome, part of the collection of the Maagdenhuis Museum (Antwerp, Belgium), is attributed to the young Anthony van Dyck (1613-1621) with reservations. The painting displays remarkable compositional and iconographic similarities with two early Van Dyck works (1618-1620) now in Museum Boijmans van Beuningen (Rotterdam) and Nationalmuseum (Stockholm). Despite these similarities, previous art historical research did not result in a clear attribution to this master. In this study, the works authenticity as a young Van Dyck painting was assessed from a technical perspective by employing a twofold approach. First, technical information on Van Dycks materials and techniques, here identified as his fingerprint, were defined based on a literature review. Second, the materials and techniques of the questioned Saint Jerome painting were characterized by using complementary imaging techniques: infrared reflectography, X-ray radiography and macro X-ray fluorescence scanning. The insights from this non-invasive research were supplemented with analysis of a limited number of cross-sections by means of field emission scanning electron microscopy coupled with energy dispersive X-ray spectroscopy. The results demonstrated that the questioned paintings materials and techniques deviate from Van Dycks fingerprint, thus making the authorship of this master very unlikely.
Keywords: A1 Journal article; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)
Times cited: 1
DOI: 10.1186/S40494-017-0136-3
|
|
“Land-use suitability in Northeast Iran : application of AHP-GIS hybrid model”. Memarbashi E, Azadi H, Barati AA, Mohajeri F, Van Passel S, Witlox F, Isprs International Journal Of Geo-Information 6, 396 (2017). http://doi.org/10.3390/IJGI6120396
Abstract: Land-use suitability is the ability of a given type of land to support a defined use. Analysis of land-use suitability requires the consideration of a variety of criteria, not only the natural/physical capacity of a land unit, but also its socioeconomic and environmental impact implications. As land suitability is assessed within a Geographic Information System (GIS) environment, it is formulated as a multi-criteria decision making (MCDM) problem. The study was conducted in the Sangab Plain in northeast Iran. We investigated the study areas suitability for grassland and agricultural uses. A hybrid method of the analytic hierarchy process (AHP) and GIS methodology was applied to evaluate land suitability based on a set of criteria and sub-criteria. Results showed that 20% of the study area had high (rich), 65% had medium (fair), and 15% had low (poor) suitability for agriculture. In terms of grassland use, the comparable amounts were, respectively, about 7%, 23%, and 70%. The lands of the Sangab Plain have medium potential for agricultural use and low potential for grassland use. This paper used both qualitative and quantitative techniques.
Keywords: A1 Journal article; Economics; Engineering Management (ENM); Government and Law
Impact Factor: 0.371
Times cited: 7
DOI: 10.3390/IJGI6120396
|
|
“Controlled growth of hexagonal gold nanostructures during thermally induced self-assembling on Ge(001) surface”. Jany BR, Gauquelin N, Willhammar T, Nikiel M, van den Bos KHW, Janas A, Szajna K, Verbeeck J, Van Aert S, Van Tendeloo G, Krok F, Scientific reports 7, 42420 (2017). http://doi.org/10.1038/srep42420
Abstract: Nano-sized gold has become an important material in various fields of science and technology, where control over the size and crystallography is desired to tailor the functionality. Gold crystallizes in the face-centered cubic (fcc) phase, and its hexagonal closed packed (hcp) structure is a very unusual and rare phase. Stable Au hcp phase has been reported to form in nanoparticles at the tips of some Ge nanowires. It has also recently been synthesized in the form of thin graphene-supported sheets which are unstable under electron beam irradiation. Here, we show that stable hcp Au 3D nanostructures with well-defined crystallographic orientation and size can be systematically created in a process of thermally induced self-assembly of thin Au layer on Ge(001) monocrystal. The Au hcp crystallite is present in each Au nanostructure and has been characterized by different electron microscopy techniques. We report that a careful heat treatment above the eutectic melting temperature and a controlled cooling is required to form the hcp phase of Au on a Ge single crystal. This new method gives scientific prospects to obtain stable Au hcp phase for future applications in a rather simple manner as well as redefine the phase diagram of Gold with Germanium.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.259
Times cited: 25
DOI: 10.1038/srep42420
|
|
“Hampering Effect of Cholesterol on the Permeation of Reactive Oxygen Species through Phospholipids Bilayer: Possible Explanation for Plasma Cancer Selectivity”. Van der Paal J, Verheyen C, Neyts EC, Bogaerts A, Scientific reports 7, 39526 (2017). http://doi.org/10.1038/srep39526
Abstract: In recent years, the ability of cold atmospheric pressure plasmas (CAPS) to selectively induce cell death in cancer cells has been widely established. This selectivity has been assigned to the reactive oxygen and nitrogen species (RONS) created in CAPs. To provide new insights in the search for an explanation
for the observed selectivity, we calculate the transfer free energy of multiple ROS across membranes containing a varying amount of cholesterol. The cholesterol fraction is investigated as a selectivity parameter because membranes of cancer cells are known to contain lower fractions of cholesterol compared to healthy cells. We find that cholesterol has a significant effect on the permeation of
reactive species across a membrane. Indeed, depending on the specific reactive species, an increasing cholesterol fraction can lead to (i) an increase of the transfer free energy barrier height and width, (ii) the formation of a local free energy minimum in the center of the membrane and (iii) the creation of extra free energy barriers due to the bulky sterol rings. In the context of plasma oncology, these observations suggest that the increased ingress of RONS in cancer cells can be explained by the decreased cholesterol fraction of their cell membrane.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.259
Times cited: 27
DOI: 10.1038/srep39526
|
|
“P-N Junction Passivation in Kesterite Solar Cells by Use of Solution-Processed TiO2 Layer”. Ranjbar S, Hadipour A, Vermang B, Batuk M, Hadermann J, Garud S, Sahayaraj S, Meuris M, Brammertz G, da Cunha AF, Poortmans J, IEEE journal of photovoltaics 7, 1130 (2017). http://doi.org/10.1109/JPHOTOV.2017.2692208
Abstract: In this work, we used a solution-processed TiO2 layer between Cu2ZnSnSe4 and CdS buffer layer to reduce the recombination at the p–n junction. Introducing the TiO2 layer showed a positive impact on VOC but fill factor and efficiency decreased. Using a KCN treatment, we could create openings in the TiO2 layer, as confirmed by transmission electron microscopy measurements. Formation of these openings in the TiO2 layer led to the improvement of the short-circuit current, fill factor, and the efficiency of the modified solar cells.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.712
Times cited: 2
DOI: 10.1109/JPHOTOV.2017.2692208
|
|
“Effect of head group and lipid tail oxidation in the cell membrane revealed through integrated simulations and experiments”. Yusupov M, Wende K, Kupsch S, Neyts EC, Reuter S, Bogaerts A, Scientific reports 7, 5761 (2017). http://doi.org/10.1038/s41598-017-06412-8
Abstract: We report on multi-level atomistic simulations for the interaction of reactive oxygen species (ROS) with the head groups of the phospholipid bilayer, and the subsequent effect of head group and lipid tail oxidation on the structural and dynamic properties of the cell membrane. Our simulations are validated by experiments using a cold atmospheric plasma as external ROS source. We found that plasma treatment leads to a slight initial rise in membrane rigidity, followed by a strong and persistent increase in fluidity, indicating a drop in lipid order. The latter is also revealed by our simulations. This study is important for cancer treatment by therapies producing (extracellular) ROS, such as plasma treatment. These ROS will interact with the cell membrane, first oxidizing the head groups, followed by the lipid tails. A drop in lipid order might allow them to penetrate into the cell interior (e.g., through pores created due to oxidation of the lipid tails) and cause intracellular oxidative damage, eventually leading to cell death. This work in general elucidates the underlying mechanisms of ROS interaction with the cell membrane at the atomic level.
Keywords: A1 Journal article; Engineering sciences. Technology; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 4.259
Times cited: 27
DOI: 10.1038/s41598-017-06412-8
|