|
“Hydride destabilization in core-shell nanoparticles”. Pasquini L, Sacchi M, Brighi M, Boelsma C, Bals S, Perkisas T, Dam B, International journal of hydrogen energy 39, 2115 (2014). http://doi.org/10.1016/j.ijhydene.2013.11.085
Abstract: We present a model that describes the effect of elastic constraint on the thermodynamics of hydrogen absorption and desorption in biphasic core-shell nanoparticles, where the core is a hydride forming metal. In particular, the change of the hydride formation enthalpy and of the equilibrium pressure for the metal/hydride transformation are described as a function of nanoparticles radius, shell thickness, and elastic properties of both core and shell. To test the model, the hydrogen sorption isotherms of Mg-MgO core-shell nanoparticles, synthesized by inert gas condensation, were measured by means of optical hydrogenography. The model's predictions are in good agreement with the experimentally determined plateau pressure of hydrogen absorption. The features that a core-shell systems should exhibit in view of practical hydrogen storage applications are discussed with reference to the model and the experimental results. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.582
Times cited: 32
DOI: 10.1016/j.ijhydene.2013.11.085
|
|
|
“The effect of microstructure on the hydrogenation of Mg/Fe thin film multilayers”. Mooij L, Perkisas T, Palsson G, Schreuders H, Wolff M, Hjorvarsson B, Bals S, Dam B, International journal of hydrogen energy 39, 17092 (2014). http://doi.org/10.1016/j.ijhydene.2014.08.035
Abstract: Nanoconfined magnesium hydride can be simultaneously protected and thermodynamically destabilized when interfaced with materials such as Ti and Fe. We study the hydrogenation of thin layers of Mg (<14 nm) nanoconfined in one dimension within thin film Fe/Mg/Fe/Pd multilayers by the optical technique Hydrogenography. The hydrogenation of nanosized magnesium layers in Fe/Mg/Fe multilayers surprisingly shows the presence of multiple plateau pressures, whose nature is thickness dependent. In contrast, hydrogen desorption occurs via a single plateau which does not depend on the Mg layer thickness. From structural and morphological analyses with X-ray diffraction/reflectometry and cross-section TEM, we find that the Mg layer roughness is large when deposited on Fe and furthermore contains high-angle grain boundaries (GB's). When grown on Ti, the Mg layer roughness is low and no high-angle GB's are detected. From a Ti/Mg/Fe multilayer, in which the Mg layer is flat and has little or no GB's, we conclude that MgH2 is indeed destabilized by the interface with Fe. In this case, both the ab- and desorption plateau pressures are increased by a factor two compared to the hydrogenation of Mg within Ti/Mg/Ti multilayers. We hypothesize that the GB's in the Fe/Mg/Fe multilayer act as diffusion pathways for Pd, which is known to greatly alter the hydrogenation behavior of Mg when the two materials share an interface. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.582
Times cited: 15
DOI: 10.1016/j.ijhydene.2014.08.035
|
|
|
“Nanostructured materials for solid-state hydrogen storage : a review of the achievement of COST Action MP1103”. Callini E, Aguey-Zinsou KF, Ahuja R, Ares JR, Bals S, Biliškov N, Chakraborty S, Charalambopoulou G, Chaudhary AL, Cuevas F, Dam B, de Jongh P, Dornheim M, Filinchuk Y, Grbović, Novaković, J, Hirscher M, Jensen TR, Jensen PB, Novaković, N, Lai Q, Leardini F, Gattia DM, Pasquini L, Steriotis T, Turner S, Vegge T, Züttel A, Montone A, International journal of hydrogen energy
T2 –, E-MRS Fall Meeting / Symposium C on Hydrogen Storage in Solids -, Materials, Systems and Aplication Trends, SEP 15-18, 2015, Warsaw, POLAND 41, 14404 (2016). http://doi.org/10.1016/j.ijhydene.2016.04.025
Abstract: In the framework of the European Cooperation in Science and Technology (COST) Action MP1103 Nanostructured Materials for Solid-State Hydrogen Storage were synthesized, characterized and modeled. This Action dealt with the state of the art of energy storage and set up a competitive and coordinated network capable to define new and unexplored ways for Solid State Hydrogen Storage by innovative and interdisciplinary research within the European Research Area. An important number of new compounds have been synthesized: metal hydrides, complex hydrides, metal halide ammines and amidoboranes. Tuning the structure from bulk to thin film, nanoparticles and nanoconfined composites improved the hydrogen sorption properties and opened the perspective to new technological applications. Direct imaging of the hydrogenation reactions and in situ measurements under operando conditions have been carried out in these studies. Computational screening methods allowed the prediction of suitable compounds for hydrogen storage and the modeling of the hydrogen sorption reactions on mono-, bi-, and three-dimensional systems. This manuscript presents a review of the main achievements of this Action. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.582
Times cited: 89
DOI: 10.1016/j.ijhydene.2016.04.025
|
|
|
“TiO2 Films Modified with Au Nanoclusters as Self-Cleaning Surfaces under Visible Light”. Liao T-W, Verbruggen S, Claes N, Yadav A, Grandjean D, Bals S, Lievens P, Nanomaterials 8, 30 (2018). http://doi.org/10.3390/nano8010030
Abstract: In this study, we applied cluster beam deposition (CBD) as a new approach for fabricating efficient plasmon-based photocatalytic materials. Au nanoclusters (AuNCs) produced in the gas phase were deposited on TiO2 P25-coated silicon wafers with coverage ranging from 2 to 8 atomic monolayer (ML) equivalents. Scanning Electron Microscopy (SEM) images of the AuNCs modified TiO2 P25 films show that the surface is uniformly covered by the AuNCs that remain isolated at low coverage (2 ML, 4 ML) and aggregate at higher coverage (8 ML). A clear relationship between AuNCs coverage and photocatalytic activity towards stearic acid photo-oxidation was measured, both under ultraviolet and green light illumination. TiO2 P25 covered with 4 ML AuNCs showed the best stearic acid photo-oxidation performance under green light illumination (Formal Quantum Efficiency 1.6 x 10-6 over a period of 93 h). These results demonstrate the large potential of gas-phase AuNCs beam deposition technology for the fabrication of visible light active plasmonic photocatalysts.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 3.553
Times cited: 29
DOI: 10.3390/nano8010030
|
|
|
“Exploring the Optical and Morphological Properties of Ag and Ag/TiO2 Nanocomposites Grown by Supersonic Cluster Beam Deposition”. Cavaliere E, Benetti G, Van Bael M, Winckelmans N, Bals S, Gavioli L, Nanomaterials 7, 442 (2017). http://doi.org/10.3390/nano7120442
Abstract: Nanocomposite systems and nanoparticle (NP) films are crucial for many applications and research fields. The structure-properties correlation raises complex questions due to the collective structure of these systems, often granular and porous, a crucial factor impacting their effectiveness and performance. In this framework, we investigate the optical and morphological properties of Ag nanoparticles (NPs) films and of Ag NPs/TiO₂ porous matrix films, one-step grown by supersonic cluster beam deposition. Morphology and structure of the Ag NPs film and of the Ag/TiO₂ (Ag/Ti 50-50) nanocomposite are related to the optical properties of the film employing spectroscopic ellipsometry (SE). We employ a simple Bruggeman effective medium approximation model, corrected by finite size effects of the nano-objects in the film structure to gather information on the structure and morphology of the nanocomposites, in particular porosity and average NPs size for the Ag/TiO₂ NP film. Our results suggest that SE is a simple, quick and effective method to measure porosity of nanoscale films and systems, where standard methods for measuring pore sizes might not be applicable.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.553
Times cited: 19
DOI: 10.3390/nano7120442
|
|
|
“Layer-by-Layer-Stabilized Plasmonic Gold-Silver Nanoparticles on TiO2: Towards Stable Solar Active Photocatalysts”. Dingenen F, Blommaerts N, Van Hal M, Borah R, Arenas-Esteban D, Lenaerts S, Bals S, Verbruggen SW, Nanomaterials 11, 2624 (2021). http://doi.org/10.3390/nano11102624
Abstract: To broaden the activity window of TiO2, a broadband plasmonic photocatalyst has been designed and optimized. This plasmonic ‘rainbow’ photocatalyst consists of TiO2 modified with gold–silver composite nanoparticles of various sizes and compositions, thus inducing a broadband interaction with polychromatic solar light. However, these nanoparticles are inherently unstable, especially due to the use of silver. Hence, in this study the application of the layer-by-layer technique is introduced to create a protective polymer shell around the metal cores with a very high degree of control. Various TiO2 species (pure anatase, PC500, and P25) were loaded with different plasmonic metal loadings (0–2 wt %) in order to identify the most solar active composite materials. The prepared plasmonic photocatalysts were tested towards stearic acid degradation under simulated sunlight. From all materials tested, P25 + 2 wt % of plasmonic ‘rainbow’ nanoparticles proved to be the most promising (56% more efficient compared to pristine P25) and was also identified as the most cost-effective. Further, 2 wt % of layer-by-layer-stabilized ‘rainbow’ nanoparticles were loaded on P25. These layer-by-layer-stabilized metals showed superior stability under a heated oxidative atmosphere, as well as in a salt solution. Finally, the activity of the composite was almost completely retained after 1 month of aging, while the nonstabilized equivalent lost 34% of its initial activity. This work shows for the first time the synergetic application of a plasmonic ‘rainbow’ concept and the layer-by-layer stabilization technique, resulting in a promising solar active, and long-term stable photocatalyst.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 3.553
Times cited: 7
DOI: 10.3390/nano11102624
|
|
|
“Hydrophilic Pt nanoflowers: synthesis, crystallographic analysis and catalytic performance”. Mourdikoudis S, Altantzis T, Liz-Marzan LM, Bals S, Pastoriza-Santos I, Perez-Juste J, CrystEngComm 18, 3422 (2016). http://doi.org/10.1039/C6CE00039H
Abstract: Water-soluble Pt nanoflowers (NFs) were prepared by a diethylene glycol-mediated reduction of Pt acetylacetonate
(Pt(acac)2) in the presence of polyethyleneimine. Advanced electron microscopy analysis showed that NFs consist of
multiple branches with truncated cubic morphology and different crystallographic orientations. We demonstrate that the
nature of the solvent strongly influences the resulting morphology. The catalytic performance of Pt NFs in 4–nitrophenol
reduction was found to be superior to that of other nanoparticle-based catalysts. Additionally, Pt NFs display good
catalytic reusability with no loss of activity after five consecutive cycles.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.474
Times cited: 30
DOI: 10.1039/C6CE00039H
|
|
|
“Atomic scale investigation of a PbTiO3/SrRuO3/DyScO3 heterostructure”. Egoavil R, Tan H, Verbeeck J, Bals S, Smith B, Kuiper B, Rijnders G, Koster G, Van Tendeloo G, Applied physics letters 102, 223106 (2013). http://doi.org/10.1063/1.4809597
Abstract: An epitaxial PbTiO3 thin film grown on self-organized crystalline SrRuO3 nanowires deposited on a DyScO3 substrate with ordered DyO and ScO2 chemical terminations is investigated by transmission electron microscopy. In this PbTiO3/SrRuO3/DyScO3 heterostructure, the SrRuO3 nanowires are assumed to grow on only one type of substrate termination. Here, we report on the structure, morphology, and chemical composition analysis of this heterostructure. Electron energy loss spectroscopy reveals the exact termination sequence in this complex structure. The energy loss near-edge structure of the Ti-L-2,L-3, Sc-L-2,L-3, and O K edges shows intrinsic interfacial electronic reconstruction. Furthermore, PbTiO3 domain walls are observed to start at the end of the nanowires resulting in atomic steps on the film surface. (C) 2013 AIP Publishing LLC.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 12
DOI: 10.1063/1.4809597
|
|
|
“Superconducting single-phase Sr1-xLaxCuO2 thin films with improved crystallinity grown by pulsed laser deposition”. Leca V, Blank DHA, Rijnders G, Bals S, Van Tendeloo G, Applied physics letters 89 (2006). http://doi.org/10.1063/1.2339840
Abstract: Sr1-xLaxCuO2-delta (x=0.10-0.20) thin films exhibiting an oxygen-deficient 2 root 2a(p)x2 root a(p) x c structure (a(p) and c represent the cell parameters of the perovskite subcell) were epitaxially grown by means of pulsed laser deposition in low-pressure oxygen ambient. (001) KTaO3 and (001) SrTiO3 single crystals were used as substrates, with BaTiO3 as buffer layer. The Sr1-xLaxCuO2-delta films were oxidized during cooling down in order to yield the infinite-layer-type structure. By applying this method, high quality single-phase Sr1-xLaxCuO2 thin films could be obtained for 0.10 <= x <= 0.175 doping range. The films grown on BaTiO3/KTaO3 show superconductivity for 0.15 <= x <= 0.175 with optimum doping at x=0.15, in contrast with previously reported data. (c) 2006 American Institute of Physics.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 32
DOI: 10.1063/1.2339840
|
|
|
“Why are sputter deposited Nd1+xBa2-xCu3O7-\delta thin films flatter than NdBa2Cu3O7-\delta films?”.Bals S, Van Tendeloo G, Salluzzo M, Maggio-Aprile I, Applied physics letters 79, 3660 (2001). http://doi.org/10.1063/1.1421622
Abstract: High-resolution electron microscopy and scanning tunneling microscopy have been used to compare the microstructure of NdBa2Cu3O7-delta and Nd1+xBa2-xCu3O7-delta thin films. Both films contain comparable amounts of Nd2CuO4 inclusions. Antiphase boundaries are induced by unit cell high steps at the substrate or by a different interface stacking. In Nd1+xBa2-xCu3O7-delta the antiphase boundaries tend to annihilate by the insertion of extra Nd layers. Stacking faults, which can be characterized as local Nd2Ba2Cu4O9 inclusions, also absorb the excess Nd. A correlation is made between the excess Nd and the absence of growth spirals at the surface of the Nd-rich films. (C) 2001 American Institute of Physics.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.411
Times cited: 13
DOI: 10.1063/1.1421622
|
|
|
“Nanoscale mapping by electron energy-loss spectroscopy reveals evolution of organic solar cell contact selectivity”. Guerrero A, Pfannmöller M, Kovalenko A, Ripolles TS, Heidari H, Bals S, Kaufmann L-D, Bisquert J, Garcia-Belmonte G, Organic electronics: physics, materials, applications 16, 227 (2015). http://doi.org/10.1016/j.orgel.2014.11.007
Abstract: Organic photovoltaic (OPV) devices are on the verge of commercialization being long-term stability a key challenge. Morphology evolution during lifetime has been suggested to be one of the main pathways accounting for performance degradation. There is however a lack of certainty on how specifically the morphology evolution relates to individual electrical parameters on operating devices. In this work a case study is created based on a thermodynamically unstable organic active layer which is monitored over a period of one year under non-accelerated degradation conditions. The morphology evolution is revealed by compositional analysis of ultrathin cross-sections using nanoscale imaging in scanning transmission electron microscopy (STEM) coupled with electron energy-loss spectroscopy (EELS). Additionally, devices are electrically monitored in real-time using the non-destructive electrical techniques capacitance-voltage (C-V) and Impedance Spectroscopy (IS). By comparison of imaging and electrical techniques the relationship between nanoscale morphology and individual electrical parameters of device operation can be conclusively discerned. It is ultimately observed how the change in the cathode contact properties occurring after the migration of fullerene molecules explains the improvement in the overall device performance. (C) 2014 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.399
Times cited: 24
DOI: 10.1016/j.orgel.2014.11.007
|
|
|
“Heterogeneity of silica and glycan-epitope distribution in epidermal idioblast cell walls in Adiantum raddianum laminae”. Van Hoorebeke L, Leroux O, Leroux F, Mastroberti AA, Santos-Silva F, Van Loo D, Bagniewska-Zadworna A, Bals S, Popper ZA, de Araujo Mariath JE, Planta 237, 1453 (2013). http://doi.org/10.1007/s00425-013-1856-6
Abstract: Laminae of Adiantum raddianum Presl., a fern belonging to the family Pteridaceae, are characterised by the presence of epidermal fibre-like cells under the vascular bundles. These cells were thought to contain silica bodies, but their thickened walls leave no space for intracellular silica suggesting it may actually be deposited within their walls. Using advanced electron microscopy in conjunction with energy dispersive X-ray microanalysis we showed the presence of silica in the cell walls of the fibre-like idioblasts. However, it was specifically localised to the outer layers of the periclinal wall facing the leaf surface, with the thick secondary wall being devoid of silica. Immunocytochemical experiments were performed to ascertain the respective localisation of silica deposition and glycan polymers. Epitopes characteristic for pectic homogalacturonan and the hemicelluloses xyloglucan and mannan were detected in most epidermal walls, including the silica-rich cell wall layers. The monoclonal antibody, LM6, raised against pectic arabinan, labelled the silica-rich primary wall of the epidermal fibre-like cells and the guard cell walls, which were also shown to contain silica. We hypothesise that the silicified outer wall layers of the epidermal fibre-like cells support the lamina during cell expansion prior to secondary wall formation. This implies that silicification does not impede cell elongation. Although our results suggest that pectic arabinan may be implicated in silica deposition, further detailed analyses are needed to confirm this. The combinatorial approach presented here, which allows correlative screening and in situ localisation of silicon and cell wall polysaccharide distribution, shows great potential for future studies.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.361
Times cited: 16
DOI: 10.1007/s00425-013-1856-6
|
|
|
“Multimodal imaging of micron-sized iron oxide particles following in vitro and in vivo uptake by stem cells: down to the nanometer scale”. Roose D, Leroux F, de Vocht N, Guglielmetti C, Pintelon I, Adriaensen D, Ponsaerts P, van der Linden A-M, Bals S, Contrast media and molecular imaging 9, 400 (2014). http://doi.org/10.1002/cmmi.1589
Abstract: In this study, the interaction between cells and micron-sized paramagnetic iron oxide (MPIO) particles was investigated by characterizing MPIO in their original state, and after cellular uptake in vitro as well as in vivo. Moreover, MPIO in the olfactory bulb were studied 9months after injection. Using various imaging techniques, cell-MPIO interactions were investigated with increasing spatial resolution. Live cell confocal microscopy demonstrated that MPIO co-localize with lysosomes after in vitro cellular uptake. In more detail, a membrane surrounding the MPIO was observed by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). Following MPIO uptake in vivo, the same cell-MPIO interaction was observed by HAADF-STEM in the subventricular zone at 1week and in the olfactory bulb at 9months after MPIO injection. These findings provide proof for the current hypothesis that MPIO are internalized by the cell through endocytosis. The results also show MPIO are not biodegradable, even after 9months in the brain. Moreover, they show the possibility of HAADF-STEM generating information on the labeled cell as well as on the MPIO. In summary, the methodology presented here provides a systematic route to investigate the interaction between cells and nanoparticles from the micrometer level down to the nanometer level and beyond. Copyright (c) 2014 John Wiley Sons, Ltd.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Bio-Imaging lab
Impact Factor: 3.307
Times cited: 5
DOI: 10.1002/cmmi.1589
|
|
|
“Multimodal imaging of micron-sized iron oxide particles following in vitro and in vivo uptake by stem cells: down to the nanometer scale”. Roose D, Leroux F, De Vocht N, Guglielmetti C, Pintelon I, Adriaensen D, Ponsaerts P, Van der Linden A, Bals S, Contrast Media &, Molecular Imaging 9, 400 (2014). http://doi.org/10.1002/cmmi.1594
Abstract: In this study, the interaction between cells and micron-sized paramagnetic iron oxide (MPIO) particles was investigated by characterizing MPIO in their original state, and after cellular uptake in vitro as well as in vivo. Moreover, MPIO in the olfactory bulb were studied 9 months after injection. Using various imaging techniques, cell-MPIO interactions were investigated with increasing spatial resolution. Live cell confocal microscopy demonstrated that MPIO co-localize with lysosomes after in vitro cellular uptake. In more detail, a membrane surrounding the MPIO was observed by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). Following MPIO uptake in vivo, the same cell-MPIO interaction was observed by HAADF-STEM in the subventricular zone at 1 week and in the olfactory bulb at 9 months after MPIO injection. These findings provide proof for the current hypothesis that MPIO are internalized by the cell through endocytosis. The results also show MPIO are not biodegradable, even after 9 months in the brain. Moreover, they show the possibility of HAADF-STEM generating information on the labeled cell as well as on the MPIO. In summary, the methodology presented here provides a systematic route to investigate the interaction between cells and nanoparticles from the micrometer level down to the nanometer level and beyond.
Keywords: A1 Journal article; Electron Microscopy for Materials Science (EMAT);
Impact Factor: 3.307
Times cited: 8
DOI: 10.1002/cmmi.1594
|
|
|
“Optical enhancement of a printed organic tandem solar cell using diffractive nanostructures”. Mayer JA, Offermans T, Chrapa M, Pfannmöller M, Bals S, Ferrini R, Nisato G, Optics express 26, A240 (2018). http://doi.org/10.1364/OE.26.00A240
Abstract: Solution processable organic tandem solar cells offer a promising approach to achieve cost-effective, lightweight and flexible photovoltaics. In order to further enhance the efficiency of optimized organic tandem cells, diffractive light-management nanostructures were designed for an optimal redistribution of the light as function of both wavelength and propagation angles in both sub-cells. As the fabrication of these optical structures is compatible with roll-to-roll production techniques such as hot-embossing or UV NIL imprinting, they present an optimal cost-effective solution for printed photovoltaics. Tandem cells with power conversion efficiencies of 8-10% were fabricated in the ambient atmosphere by doctor blade coating, selected to approximate the conditions during roll-to-roll manufacturing. Application of the light management structure onto an 8.7% efficient encapsulated tandem cell boosted the conversion efficiency of the cell to 9.5%. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.307
Times cited: 9
DOI: 10.1364/OE.26.00A240
|
|
|
“Linearized radially polarized light for improved precision in strain measurements using micro-Raman spectroscopy”. Prabhakara V, Nuytten T, Bender H, Vandervorst W, Bals S, Verbeeck J, Optics Express 29, 34531 (2021). http://doi.org/10.1364/OE.434726
Abstract: Strain engineering in semiconductor transistor devices has become vital in the semiconductor industry due to the ever-increasing need for performance enhancement at the nanoscale. Raman spectroscopy is a non-invasive measurement technique with high sensitivity to mechanical stress that does not require any special sample preparation procedures in comparison to characterization involving transmission electron microscopy (TEM), making it suitable for inline strain measurement in the semiconductor industry. Indeed, at present, strain measurements using Raman spectroscopy are already routinely carried out in semiconductor devices as it is cost effective, fast and non-destructive. In this paper we explore the usage of linearized radially polarized light as an excitation source, which does provide significantly enhanced accuracy and precision as compared to linearly polarized light for this application. Numerical simulations are done to quantitatively evaluate the electric field intensities that contribute to this enhanced sensitivity. We benchmark the experimental results against TEM diffraction-based techniques like nano-beam diffraction and Bessel diffraction. Differences between both approaches are assigned to strain relaxation due to sample thinning required in TEM setups, demonstrating the benefit of Raman for nondestructive inline testing.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.307
Times cited: 2
DOI: 10.1364/OE.434726
|
|
|
“Synthesis of IWW-type germanosilicate zeolite using 5-azonia-spiro[4, 4]nonane as structure directing agent”. Yuan R, Claes N, Verheyen E, Tuel A, Bals S, Breynaert E, Martens J, Kirschhock CEA, New journal of chemistry 40, 4319 (2016). http://doi.org/10.1039/C5NJ03094C
Abstract: IWW-type zeolite with Si/Ge of 4.9 is obtained using 5-azonia-spiro[4,4]nonane as template in fluoride-free medium under hydrothermal conditions at 175 °C. In an otherwise identical synthesis, using the related 5-azonia-spiro[4,5]decane as structure directing agent, a mixture of IWW and NON zeolite types was formed. In absence of GeO2 from the reactant mixture, pure NON formed. The IWW zeolite was characterized by XRD, SEM, and HRTEM. IWW zeolite displayed a unique morphology and could be calcined at 600 °C without loss of crystallinity. The Si/Ge ratio of the IWW zeolite was increased by postsynthesis modification. Part of the germanium could be eliminated from the as-synthesized IWW zeolite by acid leaching using 6 M HCl solution. Also the calcined material could be degermanated. Here the presence of a silicon source in the acidic leaching solution minimized structural damage. This way the Si/Ge ratio of the IWW zeolite was increased from 4.9 up to 10.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.269
Times cited: 8
DOI: 10.1039/C5NJ03094C
|
|
|
“Glycogen as a biodegradable construction nanomaterial for in vivo use”. Filippov SK, Sedlacek O, Bogomolova A, Vetrik M, Jirak D, Kovar J, Kucka J, Bals S, Turner S, Stepanek P, Hruby M;, Macromolecular bioscience 12, 1731 (2012). http://doi.org/10.1002/mabi.201200294
Abstract: It is demonstrated that glycogen as a biodegradable and inexpensive material coming from renewable resources can be used as a carrier for the construction of in vivo imaging nanoagents. The model system considered is composed of glycogen modified with gadolinium and fluorescent labels. Systematic studies of properties of these nanocarriers by a variety of physical methods and results of in vivo tests of biodegradability are reported. This represents, to the authors' best knowledge, the first such use of glycogen.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.238
Times cited: 22
DOI: 10.1002/mabi.201200294
|
|
|
“Low-dose patterning of platinum nanoclusters on carbon nanotubes by focused-electron-beam-induced deposition as studied by TEM”. Ke X, Bittencourt C, Bals S, Van Tendeloo G, Beilstein journal of nanotechnology 4, 77 (2013). http://doi.org/10.3762/bjnano.4.9
Abstract: Focused-electron-beam-induced deposition (FEBID) is used as a direct-write approach to decorate ultrasmall Pt nanoclusters on carbon nanotubes at selected sites in a straightforward maskless manner. The as-deposited nanostructures are studied by transmission electron microscopy (TEM) in 2D and 3D, demonstrating that the Pt nanoclusters are well-dispersed, covering the selected areas of the CNT surface completely. The ability of FEBID to graft nanoclusters on multiple sides, through an electron-transparent target within one step, is unique as a physical deposition method. Using high-resolution TEM we have shown that the CNT structure can be well preserved thanks to the low dose used in FEBID. By tuning the electron-beam parameters, the density and distribution of the nanoclusters can be controlled. The purity of as-deposited nanoclusters can be improved by low-energy electron irradiation at room temperature.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.127
Times cited: 12
DOI: 10.3762/bjnano.4.9
|
|
|
“Atomic layer deposition-based synthesis of photoactive TiO2 nanoparticle chains by using carbon nanotubes as sacrificial templates”. Deng S, Verbruggen SW, He Z, Cott DJ, Vereecken PM, Martens JA, Bals S, Lenaerts S, Detavernier C, RSC advances 4, 11648 (2014). http://doi.org/10.1039/c3ra42928h
Abstract: Highly ordered and self supported anatase TiO2 nanoparticle chains were fabricated by calcining conformally TiO2 coated multi-walled carbon nanotubes (MWCNTs). During annealing, the thin tubular TiO2 coating that was deposited onto the MWCNTs by atomic layer deposition (ALD) was transformed into chains of TiO2 nanoparticles ([similar]12 nm diameter) with an ultrahigh surface area (137 cm2 per cm2 of substrate), while at the same time the carbon from the MWCNTs was removed. Photocatalytic tests on the degradation of acetaldehyde proved that these forests of TiO2 nanoparticle chains are highly photoactive under UV light because of their well crystallized anatase phase.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 3.108
Times cited: 45
DOI: 10.1039/c3ra42928h
|
|
|
“New insights into the mesophase transformation of ethane-bridged PMOs by the influence of different counterions under basic conditions”. Lin F, Meng, Kukueva E, Mertens M, Van Doorslaer S, Bals S, Cool P, RSC advances 5, 5553 (2015). http://doi.org/10.1039/c4ra15849k
Abstract: The counterions are of crucial importance in determining the mesostructure and morphology of ethanebridged PMO materials synthesized under basic conditions. By using CTABr as the surfactant, the final PMO materials show a 2-D hexagonal (p6mm) mesophase, while PMO materials with cubic (Pm (3) over barn ) mesostructure are obtained when CTACl or CTA(SO4)(1)/(2) are used. With gradually replacing CTABr by CTACl or CTA(SO4) (1)/(2) while keeping the total surfactant concentration constant, a clear p6mm to Pm (3) over barn 3n mesophase evolution process is observed. For a given gel composition, the mesophase of ethanebridged PMO materials can also be adjusted by the addition of different sodium salts. In short, the effect of the counterions on the mesophase can be attributed to the binding strength of the ions on the surfactant micelles, which follows the Hofmeister series (SO42- < Cl- < Br-< NO3- < SCN-). Furthermore, it is found that the hydrolysis and condensation rate of the organosilica precursor also plays an important role in the formation of the final mesostructure
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 3.108
Times cited: 6
DOI: 10.1039/c4ra15849k
|
|
|
“Single-step alcohol-free synthesis of coreshell nanoparticles of \gamma-casein micelles and silica”. Kerkhofs S, Leroux F, Allouche L, Mellaerts R, Jammaer J, Aerts A, Kirschhock CEA, Magusin PCMM, Taulelle F, Bals S, Van Tendeloo G, Martens JA;, RSC advances 4, 25650 (2014). http://doi.org/10.1039/C4RA03252G
Abstract: A new, single-step protocol for wrapping individual nanosized β-casein micelles with silica is presented. This biomolecule-friendly synthesis proceeds at low protein concentration at almost neutral pH, and makes use of sodium silicate instead of the common silicon alkoxides. This way, formation of potentially protein-denaturizing alcohols can be avoided. The pH of the citrate-buffered synthesis medium is close to the isoelectric point of β-casein, which favours micelle formation. A limited amount of sodium silicate is added to the protein micelle suspension, to form a thin silica coating around the β-casein micelles. The size distribution of the resulting proteinsilica structures was characterized using DLS and SAXS, as well as 1H NMR DOSY with a dedicated pulsed-field gradient cryo-probehead to cope with the low protein concentration. The degree of silica-condensation was investigated by 29Si MAS NMR, and the nanostructure was revealed by advanced electron microscopy techniques such as ESEM and HAADF-STEM. As indicated by the combined characterization results, a silica shell of 2 nm is formed around individual β-casein micelles giving rise to separate protein coresilica shell nanoparticles of 17 nm diameter. This alcohol-free method at mild temperature and pH is potentially suited for packing protein molecules into bio-compatible silica nanocapsules for a variety of applications in biosensing, therapeutic protein delivery and biocatalysis.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.108
Times cited: 3
DOI: 10.1039/C4RA03252G
|
|
|
“Al2O3-Supported Transition Metals for Plasma-Catalytic NH3 Synthesis in a DBD Plasma: Metal Activity and Insights into Mechanisms”. Gorbanev Y, Engelmann Y, van’t Veer K, Vlasov E, Ndayirinde C, Yi Y, Bals S, Bogaerts A, Catalysts 11, 1230 (2021). http://doi.org/10.3390/catal11101230
Abstract: N2 fixation into NH3 is one of the main processes in the chemical industry. Plasma catalysis is among the environmentally friendly alternatives to the industrial energy-intensive Haber-Bosch process. However, many questions remain open, such as the applicability of the conventional catalytic knowledge to plasma. In this work, we studied the performance of Al2O3-supported Fe, Ru, Co and Cu catalysts in plasma-catalytic NH3 synthesis in a DBD reactor. We investigated the effects of different active metals, and different ratios of the feed gas components, on the concentration and production rate of NH3, and the energy consumption of the plasma system. The results show that the trend of the metal activity (common for thermal catalysis) does not appear in the case of plasma catalysis: here, all metals exhibited similar performance. These findings are in good agreement with our recently published microkinetic model. This highlights the virtual independence of NH3 production on the metal catalyst material, thus validating the model and indicating the potential contribution of radical adsorption and Eley-Rideal reactions to the plasma-catalytic mechanism of NH3 synthesis.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT); Movement Antwerp (MOVANT)
Impact Factor: 3.082
Times cited: 19
DOI: 10.3390/catal11101230
|
|
|
“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
|
|
|
“Size-controlled electrodeposition of Cu nanoparticles on gas diffusion electrodes in methanesulfonic acid solution”. Pacquets L, Irtem E, Neukermans S, Daems N, Bals S, Breugelmans T, Journal Of Applied Electrochemistry 51 (2020). http://doi.org/10.1007/S10800-020-01474-5
Abstract: In this paper electrodeposition is used to obtain Cu nanoparticles, as it allows good control over particle size and distribution. These Cu particles were deposited onto a gas diffusion electrode which increased the resulting surface area. Prior to deposition, the surface was pre-treated with NaOH, HNO3, MQ and TX100 to investigate the influence on the electrodeposition of Cu on the gas diffusion electrode (GDE). When using HNO3, the smallest particles with the most homogeneous distribution and high particle roughness were obtained. Once the optimal substrate was determined, we further demonstrated that by altering the electrodeposition parameters, the particle size and density could be tuned. On the one hand, increasing the nucleation potential led to a higher particle density resulting in smaller particles because of an increased competition between particles. Finally, the Cu particle size increased when applying a greater growth charge and growth potential. This fundamental study thus opens up a path towards the synthesis of supported Cu materials with increased surface areas, which is interesting from a catalytic point of view. Larger surface areas are generally correlated with a better catalyst performance and thus higher product yields. This research can contributed in obtaining new insides into the deposition of metallic nanoparticles on rough surfaces. [GRAPHICS] .
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT)
Impact Factor: 2.9
Times cited: 3
DOI: 10.1007/S10800-020-01474-5
|
|
|
“Partial hydrolysis of diphosphonate ester during the formation of hybrid Tio₂, nanoparticles : role of acid concentration”. Ramesha BM, Pawlak B, Arenas Esteban D, Reekmans G, Bals S, Marchal W, Carleer R, Adriaensens P, Meynen V, ChemPhysChem : a European journal of chemical physics and physical chemistry , e202300437 (2023). http://doi.org/10.1002/CPHC.202300437
Abstract: In the present work, a method was utilized to control the in‐situ partial hydrolysis of a diphosphonate ester in presence of a titania precursor and in function of acid content and its impact on the hybrid nanoparticles was assessed. The hydrolysis degree of organodiphosphonate ester linkers during the formation of hybrid organic‐inorganic metal oxide nanoparticles, are relatively underexplored . Quantitative solution NMR spectroscopy revealed that during the synthesis of TiO2 nanoparticles, an increase in acid concentration introduces a higher degree of partial hydrolysis of the TEPD linker into diverse acid/ester derivatives of TEPD. Increasing the HCl/Ti ratio from 1 to 3, resulted in an increase in degree of partial hydrolysis of the TEPD linker in solution from 4% to 18.8% under the here applied conditions. As a result of the difference in partial hydrolysis, the linker‐TiO2 bonding was altered. Upon subsequent drying of the colloidal TiO2 solution, different textures, at nanoscale and macroscopic scale, were obtained dependent on the HCl/Ti ratio and thus the degree of hydrolysis of TEPD. Understanding such linker‐TiO2 nanoparticle surface dynamics is crucial for making hybrid organic‐inorganic materials (i.e. (porous) metal phosphonates) employed in applications such as electronic/photonic devices, separation technology and heterogeneous catalysts.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 2.9
DOI: 10.1002/CPHC.202300437
|
|
|
“Barrier efficiency of sponge-like La2Zr2O7 buffer layers for YBCO-coated conductors”. Molina L, Tan H, Biermans E, Batenburg KJ, Verbeeck J, Bals S, Van Tendeloo G, Superconductor science and technology 24, 065019 (2011). http://doi.org/10.1088/0953-2048/24/6/065019
Abstract: Solution derived La2Zr2O7 films have drawn much attention for potential applications as thermal barriers or low-cost buffer layers for coated conductor technology. Annealing and coating parameters strongly affect the microstructure of La2Zr2O7, but different film processing methods can yield similar microstructural features such as nanovoids and nanometer-sized La2Zr2O7 grains. Nanoporosity is a typical feature found in such films and the implications for the functionality of the films are investigated by a combination of scanning transmission electron microscopy (STEM), electron energy-loss spectroscopy (EELS) and quantitative electron tomography. Chemical solution based La2Zr2O7 films deposited on flexible Ni5 at.%W substrates with a {100}lang001rang biaxial texture were prepared for an in-depth characterization. A sponge-like structure composed of nanometer-sized voids is revealed by high-angle annular dark-field scanning transmission electron microscopy in combination with electron tomography. A three-dimensional quantification of nanovoids in the La2Zr2O7 film is obtained on a local scale. Mostly non-interconnected highly faceted nanovoids compromise more than one-fifth of the investigated sample volume. The diffusion barrier efficiency of a 170 nm thick La2Zr2O7 film is investigated by STEM-EELS, yielding a 1.8 ± 0.2 nm oxide layer beyond which no significant nickel diffusion can be detected and intermixing is observed. This is of particular significance for the functionality of YBa2Cu3O7 − δ coated conductor architectures based on solution derived La2Zr2O7 films as diffusion barriers.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Impact Factor: 2.878
Times cited: 31
DOI: 10.1088/0953-2048/24/6/065019
|
|
|
“The superconducting proximity effect in epitaxial Al/Pb nanocomposites”. Wang H, Picot T, Houben K, Moorkens T, Grigg J, Van Haesendonck C, Biermans E, Bals S, Brown SA, Vantomme A, Temst K, Van Bael MJ;, Superconductor science and technology 27, 015008 (2014). http://doi.org/10.1088/0953-2048/27/1/015008
Abstract: We have investigated the superconducting properties of Pb nanoparticles with a diameter ranging from 8 to 20 nm, synthesized by Pb+ ion implantation in a crystalline Al matrix. A detailed structural characterization of the nanocomposites reveals the highly epitaxial relation between the Al crystalline matrix and the Pb nanoparticles. The Al/Pb nanocomposites display a single superconducting transition, with the critical temperature T-c increasing with the Pb content. The dependence of T-c on the Pb/Al volume ratio was compared with theoretical models of the superconducting proximity effect based on the bulk properties of Al and Pb. A very good correspondence with the strong-coupling proximity effect model was found, with an electron-phonon coupling constant in the Pb nanoparticles slightly reduced compared to bulk Pb. Our result differs from other studies on Pb nanoparticle based proximity systems where weak-coupling models were found to better describe the T-c dependence. We infer that the high interface quality resulting from the ion implantation synthesis method is a determining factor for the superconducting properties. Critical field and critical current measurements support the high quality of the nanocomposite superconducting films.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.878
Times cited: 2
DOI: 10.1088/0953-2048/27/1/015008
|
|
|
“Deposition of aminosilane coatings on porous Al2O3microspheres by means of dielectric barrier discharges”. Garzia Trulli M, Claes N, Pype J, Bals S, Baert K, Terryn H, Sardella E, Favia P, Vanhulsel A, Plasma processes and polymers 14, 1600211 (2017). http://doi.org/10.1002/ppap.201600211
Abstract: Advances in the synthesis of porous microspheres and in their functionalization are increasing the interest in applications of alumina. This paper deals with coatings plasma deposited from 3-aminopropyltriethoxysilane by means of dielectric barrier discharges on alumina porous microspheres, shaped by a vibrational droplet coagulation technique. Aims of the work are the functionalization of the particles with active amino groups, as well as the evaluation of their surface coverage and of the penetration of the coatings into their pores. A multi-diagnostic approach was used for the chemical/morphological characterization of the particles. It was found that 5 min exposure to plasma discharges promotes the deposition of homogeneous coatings onto the microspheres and within their pores, down to 1 μm.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA)
Impact Factor: 2.846
Times cited: 8
DOI: 10.1002/ppap.201600211
|
|