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“A Universal Deposition Protocol for Planar Heterojunction Solar Cells with High Efficiency Based on Hybrid Lead Halide Perovskite Families”. Conings B, Babayigit A, Klug M T, Bai S, Gauquelin N, Sakai N, Wang J T-W, Verbeeck J, Boyen H-G, Advanced materials 28, 10701 (2016). http://doi.org/10.1002/adma.201603747
Abstract: A robust and expedient gas quenching method is developed for the solution deposition of hybrid perovskite thin films. The method offers a reliable standard practice for the fabrication of a non-exhaustive variety of perovskites exhibiting excellent film morphology and commensurate high performance in both regular and inverted structured solar cell architectures.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 19.791
Times cited: 95
DOI: 10.1002/adma.201603747
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“State of the art and prospects for Halide Perovskite Nanocrystals”. Dey A, Ye J, De A, Debroye E, Ha SK, Bladt E, Kshirsagar AS, Wang Z, Yin J, Wang Y, Quan LN, Yan F, Gao M, Li X, Shamsi J, Debnath T, Cao M, Scheel MA, Kumar S, Steele JA, Gerhard M, Chouhan L, Xu K, Wu X-gang, Li Y, Zhang Y, Dutta A, Han C, Vincon I, Rogach AL, Nag A, Samanta A, Korgel BA, Shih C-J, Gamelin DR, Son DH, Zeng H, Zhong H, Sun H, Demir HV, Scheblykin IG, Mora-Sero I, Stolarczyk JK, Zhang JZ, Feldmann J, Hofkens J, Luther JM, Perez-Prieto J, Li L, Manna L, Bodnarchuk M I, Kovalenko M V, Roeffaers MBJ, Pradhan N, Mohammed OF, Bakr OM, Yang P, Muller-Buschbaum P, Kamat P V, Bao Q, Zhang Q, Krahne R, Galian RE, Stranks SD, Bals S, Biju V, Tisdale WA, Yan Y, Hoye RLZ, Polavarapu L, Acs Nano 15, 10775 (2021). http://doi.org/10.1021/ACSNANO.0C08903
Abstract: Metal-halide perovskites have rapidly emerged as one of the most promising materials of the 21st century, with many exciting properties and great potential for a broad range of applications, from photovoltaics to optoelectronics and photocatalysis. The ease with which metal-halide perovskites can be synthesized in the form of brightly luminescent colloidal nanocrystals, as well as their tunable and intriguing optical and electronic properties, has attracted researchers from different disciplines of science and technology. In the last few years, there has been a significant progress in the shape-controlled synthesis of perovskite nanocrystals and understanding of their properties and applications. In this comprehensive review, researchers having expertise in different fields (chemistry, physics, and device engineering) of metal-halide perovskite nanocrystals have joined together to provide a state of the art overview and future prospects of metal-halide perovskite nanocrystal research.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 13.942
Times cited: 538
DOI: 10.1021/ACSNANO.0C08903
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“Optical encoding of luminescent carbon nanodots in confined spaces”. Bartholomeeusen E, De Cremer G, Kennes K, Hammond C, Hermans I, Lu J-B, Schryvers D, Jacobs PA, Roeffaers MBJ, Hofkens J, Sels BF, Coutino-Gonzalez E, Chemical Communications 57, 11952 (2021). http://doi.org/10.1039/D1CC04777A
Abstract: Stable emissive carbon nanodots were generated in zeolite crystals using near infrared photon irradiation gradually converting the occluded organic template, originally used to synthesize the zeolite crystals, into discrete luminescent species consisting of nano-sized carbogenic fluorophores, as ascertained using Raman microscopy, and steady-state and time-resolved spectroscopic techniques. Photoactivation in a confocal laser fluorescence microscope allows 3D resolved writing of luminescent carbon nanodot patterns inside zeolites providing a cost-effective and non-toxic alternative to previously reported metal-based nanoclusters confined in zeolites, and opens up opportunities in bio-labelling and sensing applications.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 6.319
DOI: 10.1039/D1CC04777A
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“Growth mode and electronic-structure of the epitaxial C60(111)/GeS(001) interface”. Gensterblum G, Hevesi K, Han BY, Yu LM, Pireaux JJ, Thiry PA, Caudano R, Lucas AA, Bernaerts D, Amelinckx S, Van Tendeloo G, Bendele G, Buslaps T, Johnson RL, Foss M, Feidenhans’l R, Le Lay G;, Physical review : B : condensed matter and materials physics 50, 11981 (1994). http://doi.org/10.1103/PhysRevB.50.11981
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.736
Times cited: 81
DOI: 10.1103/PhysRevB.50.11981
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“An electrochemical impedimetric aptasensing platform for sensitive and selective detection of small molecules such as chloramphenicol”. Pilehvar S, Dierckx T, Blust R, Breugelmans T, De Wael K, Sensors 14, 12059 (2014). http://doi.org/10.3390/S140712059
Abstract: We report on the aptadetection of chloramphenicol (CAP) using electrochemical impedance spectroscopy. The detection principle is based on the changes of the interfacial properties of the electrode after the interaction of the ssDNA aptamers with the target molecules. The electrode surface is partially blocked due to the formation of the aptamer-CAP complex, resulting in an increase of the interfacial electron-transfer resistance of the redox probe detected by electrochemical impedance spectroscopy or cyclic voltammetry. We observed that the ratio of polarization resistance had a linear relationship with the concentrations of CAP in the range of 1.76127 nM, and a detection limit of 1.76 nM was obtained. The covalent binding of CAP-aptamer on the electrode surface combined with the unique properties of aptamers and impedimetric transduction leads to the development of a stable and sensitive electrochemical aptasensor for CAP.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Applied Electrochemistry & Catalysis (ELCAT)
Impact Factor: 2.677
Times cited: 34
DOI: 10.3390/S140712059
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“Formation of vortex clusters and giant vortices in mesoscopic superconducting disks with strong disorder”. Escoffier W, Grigorieva IV, Misko VR, Baelus BJ, Peeters FM, Vinnikov LY, Dubnos S, Journal of physics : conference series 97, 012172 (2008). http://doi.org/10.1088/1742-6596/97/1/012172
Abstract: Merged, or giant, multi-quanta vortices (GVs) appear in very small superconductors near the superconducting transition due to strong confinement of magnetic flux. Here we present evidence for a new, pinning-related, mechanism for vortex merger. Using Bitter decoration to visualise vortices in small Nb disks, we show that confinement in combination with strong disorder causes individual vortices to merge into clusters/GVs well below Tc and Hc2, in contrast to well-defined shells of individual vortices found in the absence of pinning.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
DOI: 10.1088/1742-6596/97/1/012172
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“Tunable diffusion of magnetic particles in a quasi-one-dimensional channel”. Lucena D, Ferreira WP, Munarin FF, Farias GA, Peeters FM, Physical review : E : statistical, nonlinear, and soft matter physics 87, 012307 (2013). http://doi.org/10.1103/PhysRevE.87.012307
Abstract: The diffusion of a system of ferromagnetic dipoles confined in a quasi-one-dimensional parabolic trap is studied using Brownian dynamics simulations. We show that the dynamics of the system is tunable by an in-plane external homogeneous magnetic field. For a strong applied magnetic field, we find that the mobility of the system, the exponent of diffusion, and the crossover time among different diffusion regimes can be tuned by the orientation of the magnetic field. For weak magnetic fields, the exponent of diffusion in the subdiffusive regime is independent of the orientation of the external field. DOI: 10.1103/PhysRevE.87.012307
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.366
Times cited: 11
DOI: 10.1103/PhysRevE.87.012307
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“Hierarchically dual-mesoporous TiO2 microspheres for enhanced photocatalytic properties and lithium storage”. Xiao S, Lu Y, Xiao B-Y, Wu L, Song J-P, Xiao Y-X, Wu S-M, Hu J, Wang Y, Chang G-G, Tian G, Lenaerts S, Janiak C, Yang X-Y, Su B-L, Chemistry: a European journal 24, 13246 (2018). http://doi.org/10.1002/CHEM.201801933
Abstract: Hierarchically dual‐mesoporous TiO2 microspheres have been synthesized via a solvothermal process in the presence of 1‐butyl‐3‐methylmidazolium tetrafluoroborate ([BMIm][BF4]) and diethylenetriamine (DETA) as co‐templates. Secondary mesostructured defects in the hierarchical TiO2 microspheres produce the oxygen vacancies, which not only significantly enhance the photocatalytic activity on degrading methyl blue (over 1.7 times to P25) and acetone (over 2.9 times of P25), but which also are beneficial for lithium storage. Moreover, we propose a mechanism to obtain a better understanding of the role of dual mesoporosity of TiO2 microspheres for enhancing the molecular diffusion, ion transportation and electron transformation.
Keywords: A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)
Impact Factor: 5.317
Times cited: 6
DOI: 10.1002/CHEM.201801933
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“Observation of a gel of quantum vortices in a superconductor at very low magnetic fields”. Benito Llorens J, Embon L, Correa A, Gonzalez JD, Herrera E, Guillamon I, Luccas RF, Azpeitia J, Mompean FJ, Garcia-Hernandez M, Munuera C, Aragon Sanchez J, Fasano Y, Milošević, MV, Suderow H, Anahory Y, Physical review research 2, 013329 (2020). http://doi.org/10.1103/PHYSREVRESEARCH.2.013329
Abstract: A gel consists of a network of particles or molecules formed for example using the sol-gel process, by which a solution transforms into a porous solid. Particles or molecules in a gel are mainly organized on a scaffold that makes up a porous system. Quantized vortices in type-II superconductors mostly form spatially homogeneous ordered or amorphous solids. Here we present high-resolution imaging of the vortex lattice displaying dense vortex clusters separated by sparse or entirely vortex-free regions in beta-Bi2Pd superconductor. We find that the intervortex distance diverges upon decreasing the magnetic field and that vortex lattice images follow a multifractal behavior. These properties, characteristic of gels, establish the presence of a novel vortex distribution, distinctly different from the well-studied disordered and glassy phases observed in high-temperature and conventional superconductors. The observed behavior is caused by a scaffold of one-dimensional structural defects with enhanced stress close to the defects. The vortex gel might often occur in type-II superconductors at low magnetic fields. Such vortex distributions should allow to considerably simplify control over vortex positions and manipulation of quantum vortex states.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Times cited: 14
DOI: 10.1103/PHYSREVRESEARCH.2.013329
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“Atomic-level understanding for the enhanced generation of hydrogen peroxide by the introduction of an aryl amino group in polymeric carbon nitrides”. Zhang T, Schilling W, Khan SU, Ching HYV, Lu C, Chen J, Jaworski A, Barcaro G, Monti S, De Wael K, Slabon A, Das S, Acs Catalysis 11, 14087 (2021). http://doi.org/10.1021/ACSCATAL.1C03733
Abstract: Heterogeneous catalysts are often & ldquo;black boxes & rdquo; due to the insufficient understanding of the detailed mechanisms at the catalytic sites. An atomic-level elucidation of the processes taking place in those regions is, thus, mandatory to produce robust and selective heterogeneous catalysts. We have improved the description of the whole reactive scenario for polymeric carbon nitrides (PCN) by combining atomic-level characterizations with magic-angle spinning (MAS) solid-state nuclear magnetic resonance (NMR) spectroscopy, classical reactive molecular dynamics (RMD) simulations, and quantum chemistry (QC) calculations. We disclose the structure & minus;property relationships of an ad hoc modified PCN by inserting an aryl amino group that turned out to be very efficient for the production of H2O2. The main advancement of this work is the development of a difluoromethylene-substituted aryl amino PCN to generate H2O2 at a rate of 2.0 mM & middot;h & minus;1 under the irradiation of household blue LEDs and the identification of possible active catalytic sites with the aid of 15N and 19F MAS solid-state NMR without using any expensive labeling reagent. RMD simulations and QC calculations confirm and further extend the experimental descriptions by revealing the role and locations of the identified functionalities, namely, NH linkers, & minus;NH2 terminal groups, and difluoromethylene units, reactants, and products. <comment>Superscript/Subscript Available</comment
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Organic synthesis (ORSY); Applied Electrochemistry & Catalysis (ELCAT); Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab)
Impact Factor: 10.614
DOI: 10.1021/ACSCATAL.1C03733
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“Dislocations in diamond : dissociation into partials and their glide motion”. Blumenau AT, Jones R, Frauenheim T, Willems B, Lebedev OI, Van Tendeloo G, Fisher D, Martineau PM, Physical review : B : condensed matter and materials physics 68, 014115 (2003). http://doi.org/10.1103/PhysRevB.68.014115
Abstract: The dissociation of 60degrees and screw dislocations in diamond is modeled in an approach combining isotropic elasticity theory with ab initio-based tight-binding total-energy calculations. Both dislocations are found to dissociate with a substantial lowering of their line energies. For the 60degrees dislocation, however, an energy barrier to dissociation is found. We investigate the core structure of a screw dislocation distinguishing “shuffle,” “mixed,” and “glide” cores. The latter is found to be the most stable undissociated screw dislocation. Further, the glide motion of 90degrees and 30degrees partials is discussed in terms of a process involving the thermal formation and subsequent migration of kinks along the dislocation line. The calculated activation barriers to dislocation motion show that the 30degrees partial is less mobile than the 90degrees partial. Finally, high-resolution electron microscopy is performed on high-temperature, high-pressure annealed natural brown diamond, allowing the core regions of 60degrees dislocations to be imaged. The majority of dislocations are found to be dissociated. However, in some cases, undissociated 60degrees dislocations were also observed.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 39
DOI: 10.1103/PhysRevB.68.014115
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“Computation of the thermal expansion coefficient of graphene with Gaussian approximation potentials”. Demiroglu I, Karaaslan Y, Kocabas T, Keceli M, Vazquez-Mayagoitia A, Sevik C, Journal Of Physical Chemistry C 125, 14409 (2021). http://doi.org/10.1021/ACS.JPCC.1C01888
Abstract: Direct experimental measurement of thermal expansion coefficient without substrate effects is a challenging task for two-dimensional (2D) materials, and its accurate estimation with large-scale ab initio molecular dynamics is computationally very expensive. Machine learning-based interatomic potentials trained with ab initio data have been successfully used in molecular dynamics simulations to decrease the computational cost without compromising the accuracy. In this study, we investigated using Gaussian approximation potentials to reproduce the density functional theory-level accuracy for graphene within both lattice dynamical and molecular dynamical methods, and to extend their applicability to larger length and time scales. Two such potentials are considered, GAP17 and GAP20. GAP17, which was trained with pristine graphene structures, is found to give closer results to density functional theory calculations at different scales. Further vibrational and structural analyses verify that the same conclusions can be deduced with density functional theory level in terms of the reasoning of the thermal expansion behavior, and the negative thermal expansion behavior is associated with long-range out-of-plane phonon vibrations. Thus, it is argued that the enabled larger system sizes by machine learning potentials may even enhance the accuracy compared to small-size-limited ab initio molecular dynamics.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 4.536
DOI: 10.1021/ACS.JPCC.1C01888
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“Exsolution of SrO during the Topochemical Conversion of LaSr3CoRuO8to the Oxyhydride LaSr3CoRuO4H4”. Jin L, Batuk M, Kirschner FKK, Lang F, Blundell SJ, Hadermann J, Hayward MA, Inorganic chemistry 58, 14863 (2019). http://doi.org/10.1021/acs.inorgchem.9b02552
Abstract: Reaction of the n = 1 Ruddlesden-Popper oxide LaSr3CoRuO8 with CaH2 yields the oxyhydride phase LaSr3CoRuO4H4 via topochemical anion-exchange. Close inspection of X-ray and neutron powder diffraction data in combination with HAADF-STEM images reveals that nanoparticles of SrO are exsolved from the system during the reaction, with the change in cation stoichiometry accommodated by the inclusion of n > 1 (Co/Ru)nOn+1H2n ‘perovskite’ layers into the Ruddlesden-Popper stacking sequence. This novel pseudo-topochemical process offers a new route for the formation of n > 1 Ruddlesden-Popper structured materials. Magnetization data are consistent with a LaSr3Co1+Ru2+O4H4 (Co1+, d8, S = 1; Ru2+, d6, S = 0) oxidation/spin state combination. Neutron diffraction and μ+SR data show no evidence for long-range magnetic order down to 2 K, suggesting the diamagnetic Ru2+ centers impede the Co-Co magnetic exchange interactions.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.857
Times cited: 1
DOI: 10.1021/acs.inorgchem.9b02552
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“Atomic layer deposition-based tuning of the pore size in mesoporous thin films studied by in situ grazing incidence small angle X-ray scattering”. Dendooven J, Devloo-Casier K, Ide M, Grandfield, Kurttepeli, Ludwig KF, Bals S, Van der Voort P, Detavernier C, Nanoscale 6, 14991 (2014). http://doi.org/10.1039/c4nr05049e
Abstract: Atomic layer deposition (ALD) enables the conformal coating of porous materials, making the technique suitable for pore size tuning at the atomic level, e.g., for applications in catalysis, gas separation and sensing. It is, however, not straightforward to obtain information about the conformality of ALD coatings deposited in pores with diameters in the low mesoporous regime (<10 nm). In this work, it is demonstrated that in situ synchrotron based grazing incidence small angle X-ray scattering (GISAXS) can provide valuable information on the change in density and internal surface area during ALD of TiO2 in a porous titania film with small mesopores (3-8 nm). The results are shown to be in good agreement with in situ X-ray fluorescence data representing the evolution of the amount of Ti atoms deposited in the porous film. Analysis of both datasets indicates that the minimum pore diameter that can be achieved by ALD is determined by the size of the Ti-precursor molecule.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 7.367
Times cited: 41
DOI: 10.1039/c4nr05049e
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“Coupling the COST reference plasma jet to a microfluidic device: a computational study”. Bissonnette-Dulude J, Heirman P, Coulombe S, Bogaerts A, Gervais T, Reuter S, Plasma sources science and technology 33, 015001 (2024). http://doi.org/10.1088/1361-6595/ad1421
Abstract: The use of microfluidic devices in the field of plasma-liquid interaction can unlock unique possibilities to investigate the effects of plasma-generated reactive species for environmental and biomedical applications. So far, very little simulation work has been performed on microfluidic devices in contact with a plasma source. We report on the modelling and computational simulation of physical and chemical processes taking place in a novel plasma-microfluidic platform. The main production and transport pathways of reactive species both in plasma and liquid are modelled by a novel modelling approach that combines 0D chemical kinetics and 2D transport mechanisms. This combined approach, applicable to systems where the transport of chemical species occurs in unidirectional flows at high Péclet numbers, decreases calculation times considerably compared to regular 2D simulations. It takes advantage of the low computational time of the 0D reaction models while providing spatial information through multiple plug-flow simulations to yield a quasi-2D model. The gas and liquid flow profiles are simulated entirely in 2D, together with the chemical reactions and transport of key chemical species. The model correctly predicts increased transport of hydrogen peroxide into the liquid when the microfluidic opening is placed inside the plasma effluent region, as opposed to inside the plasma region itself. Furthermore, the modelled hydrogen peroxide production and transport in the microfluidic liquid differs by less than 50% compared with experimental results. To explain this discrepancy, the limits of the 0D–2D combined approach are discussed.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.8
DOI: 10.1088/1361-6595/ad1421
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“Appearance of a conductive carbonaceous coating in a CO2dielectric barrier discharge and its influence on the electrical properties and the conversion efficiency”. Belov I, Paulussen S, Bogaerts A, Plasma sources science and technology 25, 015023 (2016). http://doi.org/10.1088/0963-0252/25/1/015023
Abstract: This work examines the properties of a dielectric barrier discharge (DBD) reactor, built for CO2 decomposition, by means of electrical characterization, optical emission spectroscopy and gas chromatography. The discharge, formed in an electronegative gas (such as CO2, but also O2), exhibits clearly different electrical characteristics, depending on the surface conductivity of the reactor walls. An asymmetric current waveform is observed in the metaldielectric (MD) configuration, with sparse high-current pulses in the positive half-cycle (HC) and a more uniform regime in the negative HC. This indicates that the discharge is operating in two alternating regimes with rather different properties. At high CO2 conversion regimes, a conductive coating is deposited on the dielectric. This so-called coated MD configuration yields a symmetric current waveform, with current peaks in both the positive and negative HCs. In a double-dielectric (DD) configuration, the current waveform is also symmetric, but without current peaks in both the positive and negative HC. Finally, the DD configuration with conductive coating on the inner surface of the outer dielectric, i.e. so-called coated DD, yields again an asymmetric current waveform, with current peaks in the negative HC. These different electrical characteristics are related to the presence of the conductive coating on the dielectric wall of the reactor and can be explained by an increase of the local barrier capacitance available for charge transfer. The different discharge regimes affect the CO2 conversion, more specifically, the CO2 conversion is lowest in the clean DD configuration. It is somewhat higher in the coated DD configuration, and still higher in the MD configuration. The clean and coated MD configuration, however, gave similar CO2 conversion. These results indicate that the conductivity of the dielectric reactor walls can highly promote the development of the high-amplitude discharge current pulses and subsequently the CO2 conversion.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.302
Times cited: 25
DOI: 10.1088/0963-0252/25/1/015023
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“Promising room temperature thermoelectric conversion efficiency of zinc-blende AgI from first principles”. Bulut P, Beceren B, Yildirim S, Sevik C, Gurel T, Journal Of Physics-Condensed Matter 33, 015501 (2021). http://doi.org/10.1088/1361-648X/ABB867
Abstract: The theoretical investigation on structural, vibrational, and electronic properties of zinc-blende (ZB) AgI were carried out employing first principles density functional theory calculations. Thermoelectric properties then were predicted through semi-classical Boltzmann transport equations within the constant relaxation time approximation. Equilibrium lattice parameter, bulk modulus, elastic constants, and vibrational properties were calculated by using generalized gradient approximation. Calculated properties are in good agreement with available experimental values. Electronic and thermoelectric properties were investigated both with and without considering spin-orbit coupling (SOC) effect which is found to have a strong influence on p-type Seebeck coefficient as well as the power factor of the ZB-AgI. By inclusion of SOC, a reduction of the band-gap and p-type Seebeck coefficients as well as the power factor was found which is the indication of that spin-orbit interaction cannot be ignored for p-type thermoelectric properties of the ZB-AgI. By using deformation potential theory for electronic relaxation time and experimentally predicted lattice thermal conductivity, we obtained aZTvalue 1.69 (0.89) at 400 K for n-type (p-type) carrier concentration of 1.5 x 10(18)(4.6 x10(19)) cm(-3)that makes ZB-AgI as a promising room temperature thermoelectric material.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 2.649
DOI: 10.1088/1361-648X/ABB867
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“Charging of vitreous samples in cryogenic electron microscopy mitigated by graphene”. Zhang Y, van Schayck JP, Pedrazo-Tardajos A, Claes N, Noteborn WEM, Lu P-H, Duimel H, Dunin-Borkowski RE, Bals S, Peters PJ, Ravelli RBG, ACS nano 17, 15836 (2023). http://doi.org/10.1021/ACSNANO.3C03722
Abstract: Cryogenic electronmicroscopy can provide high-resolution reconstructionsof macromolecules embedded in a thin layer of ice from which atomicmodels can be built de novo. However, the interactionbetween the ionizing electron beam and the sample results in beam-inducedmotion and image distortion, which limit the attainable resolutions.Sample charging is one contributing factor of beam-induced motionsand image distortions, which is normally alleviated by including partof the supporting conducting film within the beam-exposed region.However, routine data collection schemes avoid strategies wherebythe beam is not in contact with the supporting film, whose rationaleis not fully understood. Here we characterize electrostatic chargingof vitreous samples, both in imaging and in diffraction mode. We mitigatesample charging by depositing a single layer of conductive grapheneon top of regular EM grids. We obtained high-resolution single-particleanalysis (SPA) reconstructions at 2 & ANGS; when the electron beamonly irradiates the middle of the hole on graphene-coated grids, usingdata collection schemes that previously failed to produce sub 3 & ANGS;reconstructions without the graphene layer. We also observe that theSPA data obtained with the graphene-coated grids exhibit a higher b factor and reduced particle movement compared to dataobtained without the graphene layer. This mitigation of charging couldhave broad implications for various EM techniques, including SPA andcryotomography, and for the study of radiation damage and the developmentof future sample carriers. Furthermore, it may facilitate the explorationof more dose-efficient, scanning transmission EM based SPA techniques.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 17.1
DOI: 10.1021/ACSNANO.3C03722
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“Engineering excitonic dynamics and environmental stability of post-transition metal chalcogenides by pyridine functionalization technique”. Meng X, Pant A, Cai H, Kang J, Sahin H, Chen B, Wu K, Yang S, Suslu A, Peeters FM, Tongay S;, Nanoscale 7, 17109 (2015). http://doi.org/10.1039/c5nr04879f
Abstract: http://cmt.ua.ac.be/hsahin/publishedpapers/46.pdf
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 7.367
Times cited: 11
DOI: 10.1039/c5nr04879f
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“Electrochemical evidence for neuroglobin activity on NO at physiological concentrations”. Trashin S, De Jong M, Luyckx E, Dewilde S, De Wael K, Journal of biological chemistry 291, 18959 (2016). http://doi.org/10.1074/JBC.M116.730176
Abstract: The true function of neuroglobin (Ngb) and, particularly, human Ngb (NGB) has been under debate since its discovery 15 years ago. It has been expected to play a role in oxygen binding/supply, but a variety of other functions have been put forward, including NO dioxygenase activity. However, in vitro studies that could unravel these potential roles have been hampered by the lack of an Ngb-specific reductase. In this work, we used electrochemical measurements to investigate the role of an intermittent internal disulfide bridge in determining NO oxidation kinetics at physiological NO concentrations. The use of a polarized electrode to efficiently interconvert the ferric (Fe3+) and ferrous (Fe2+) forms of an immobilized NGB showed that the disulfide bridge both defines the kinetics of NO dioxygenase activity and regulates appearance of the free ferrous deoxy-NGB, which is the redox active form of the protein in contrast to oxy-NGB. Our studies further identified a role for the distal histidine, interacting with the hexacoordinated iron atom of the heme, in oxidation kinetics. These findings may be relevant in vivo, for example in blocking apoptosis by reduction of ferric cytochrome c, and gentle tuning of NO concentration in the tissues.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 4.125
Times cited: 11
DOI: 10.1074/JBC.M116.730176
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“0 and &pi, phase Josephson coupling through an insulating barrier with magnetic impurities”. Vávra O, Gaži S, Golubović, DS, Vávra I, Dérer J, Verbeeck J, Van Tendeloo G, Moshchalkov VV, Physical review : B : condensed matter and materials physics 74, 020502 (2006). http://doi.org/10.1103/PhysRevB.74.020502
Abstract: We have studied the temperature and field dependencies of the critical current I(C) in the Nb-Fe(0.1)Si(0.9)-Nb Josephson junction with a tunneling barrier formed by a paramagnetic insulator. We demonstrate that in these junctions coexistence of both the 0 and the pi states within one tunnel junction occurs, and leads to the appearance of a sharp cusp in the temperature dependence I(C)(T), similar to the I(C)(T) cusp found for the 0-pi transition in metallic pi junctions. This cusp is not related to the 0-pi temperature-induced transition itself, but is caused by the different temperature dependencies of the opposing 0 and pi supercurrents through the barrier.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 27
DOI: 10.1103/PhysRevB.74.020502
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“Unusual dimensionality effects and surface charge density in 2D Mg(OH)2”. Suslu A, Wu K, Sahin H, Chen B, Yang S, Cai H, Aoki T, Horzum S, Kang J, Peeters FM, Tongay S;, Scientific reports 6, 20525 (2016). http://doi.org/10.1038/srep20525
Abstract: We present two-dimensional Mg(OH)(2) sheets and their vertical heterojunctions with CVD-MoS2 for the first time as flexible 2D insulators with anomalous lattice vibration and chemical and physical properties. New hydrothermal crystal growth technique enabled isolation of environmentally stable monolayer Mg(OH)(2) sheets. Raman spectroscopy and vibrational calculations reveal that the lattice vibrations of Mg(OH)(2) have fundamentally different signature peaks and dimensionality effects compared to other 2D material systems known to date. Sub-wavelength electron energy-loss spectroscopy measurements and theoretical calculations show that Mg(OH)(2) is a 6 eV direct-gap insulator in 2D, and its optical band gap displays strong band renormalization effects from monolayer to bulk, marking the first experimental confirmation of confinement effects in 2D insulators. Interestingly, 2D-Mg(OH)(2) sheets possess rather strong surface polarization (charge) effects which is in contrast to electrically neutral h-BN materials. Using 2D-Mg(OH)(2) sheets together with CVD-MoS2 in the vertical stacking shows that a strong change transfer occurs from n-doped CVD-MoS2 sheets to Mg(OH)(2), naturally depleting the semiconductor, pushing towards intrinsic doping limit and enhancing overall optical performance of 2D semiconductors. Results not only establish unusual confinement effects in 2D-Mg(OH)(2), but also offer novel 2D-insulating material with unique physical, vibrational, and chemical properties for potential applications in flexible optoelectronics.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 4.259
Times cited: 39
DOI: 10.1038/srep20525
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“Assessment of sulfur-functionalized MXenes for li-ion battery applications”. Siriwardane EMD, Demiroglu I, Sevik C, Peeters FM, Çakir D, Journal Of Physical Chemistry C 124, 21293 (2020). http://doi.org/10.1021/ACS.JPCC.0C05287
Abstract: The surface termination of MXenes greatly determines the electrochemical properties and ion kinetics on their surfaces. So far, hydroxyl-, oxygen-, and fluorine-terminated MXenes have been widely studied for energy storage applications. Recently, sulfur-functionalized MXene structures, which possess low diffusion barriers, have been proposed as candidate materials to enhance battery performance. We performed first-principles calculations on the structural, stability, electrochemical, and ion dynamic properties of Li-adsorbed sulfur-functionalized groups 3B, 4B, 5B, and 6B transition-metal (M)-based MXenes (i.e., M2CS2 with M = Sc, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W). We performed phonon calculations, which indicated that all of the above M2CS2 MXenes, except for Sc, are dynamically stable at T = 0 K. The ground-state structure of each M2CS2 monolayer depends on the type of M atom. For instance, while sulfur prefers to sit at the FCC site on Ti2CS2, it occupies the HCP site of Cr-based MXene. We determined the Li adsorption configurations at different concentrations using the cluster expansion method. The highest maximum open-circuit voltages were computed for the group 4B element (i.e., Ti, Zr, and Hf)-based M2CS2, which are larger than 2.1 V, while their average voltages are approximately 1 V. The maximum voltage for the group 6B element (i.e., Cr, Mo, W)-based M2CS2 is less than 1 V, and the average voltage is less than 0.71 V. We found that S functionalization is helpful for capacity improvements over the O-terminated MXenes. In this respect, the computed storage gravimetric capacity may reach up to 417.4 mAh/g for Ti2CS2 and 404.5 mAh/g for V2CS2. Ta-, Cr-, Mo-, and W-based M2CS2 MXenes show very low capacities, which are less than 100 mAh/g. The Li surface diffusion energy barriers for all of the considered MXenes are less than 0.22 eV, which is favorable for high charging and discharging rates. Finally, ab initio molecular dynamic simulations performed at 400 K and bond-length analysis with respect to Li concentration verify that selected promising systems are robust against thermally induced perturbations that may induce structural transformations or distortions and undesirable Li release.
Keywords: A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Impact Factor: 3.7
Times cited: 24
DOI: 10.1021/ACS.JPCC.0C05287
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“La1.5Sr0.5NiMn0.5Ru0.5O6 double perovskite with enhanced ORR/OER bifunctional catalytic activity”. Retuerto M, Calle-Vallejo F, Pascual L, Lumbeeck G, Fernandez-Diaz MT, Croft M, Gopalakrishnan J, Pena MA, Hadermann J, Greenblatt M, Rojas S, ACS applied materials and interfaces 11, 21454 (2019). http://doi.org/10.1021/ACSAMI.9B02077
Abstract: Perovskites (ABO(3)) with transition metals in active B sites are considered alternative catalysts for the water oxidation to oxygen through the oxygen evolution reaction (OER) and for the oxygen reduction through the oxygen reduction reaction (ORR) back to water. We have synthesized a double perovskite (A(2)BB'O-6) with different cations in A, B, and B' sites, namely, ((La15Sr0.5)-Sr-.)(A)(Ni0.5Mn0.5)(B)(Ni0.5Ru0.5)(B)O-6 (LSNMR), which displays an outstanding OER/ORR bifunctional performance. The composition and structure of the oxide has been determined by powder X-ray diffraction, powder neutron diffraction, and transmission electron microscopy to be monoclinic with the space group P2(1)/n and with cationic ordering between the ions in the B and B' sites. X-ray absorption near-edge spectroscopy suggests that LSNMR presents a configuration of similar to Ni2+, similar to Mn4+, and similar to Ru5+. This bifunctional catalyst is endowed with high ORR and OER activities in alkaline media, with a remarkable bifunctional index value of similar to 0.83 V (the difference between the potentials measured at -1 mA cm(-2) for the ORR and +10 mA cm(-2) for the OER). The ORR onset potential (E-onset) of 0.94 V is among the best reported to date in alkaline media for ORR-active perovskites. The ORR mass activity of LSNMR is 1.1 A g(-1) at 0.9 V and 7.3 A g(-1) at 0.8 V. Furthermore, LSNMR is stable in a wide potential window down to 0.05 V. The OER potential to achieve a current density of 10 mA cm(-2) is 1.66 V. Density functional theory calculations demonstrate that the high ORR/OER activity of LSNMR is related to the presence of active Mn sites for the ORR- and Ru-active sites for the OER by virtue of the high symmetry of the respective reaction steps on those sites. In addition, the material is stable to ORR cycling and also considerably stable to OER cycling.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 7.504
Times cited: 12
DOI: 10.1021/ACSAMI.9B02077
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“On the control and effect of water content during the electrodeposition of Ni nanostructures from deep eutectic solvents”. Cherigui EAM, Şentosun K, Mamme MH, Lukaczynska M, Terryn H, Bals S, Ustarroz J, The journal of physical chemistry: C : nanomaterials and interfaces 122, 23129 (2018). http://doi.org/10.1021/acs.jpcc.8b05344
Abstract: The electrodeposition of nickel nanostructures on glassy carbon was investigated in 1:2 choline chloride urea deep eutectic solvent (DES) containing different amounts of water. By combining electrochemical techniques, with ex situ field emission scanning electron microscopy, high-angle annular dark field scanning transmission electron microscopy, and energy-dispersive X-ray spectroscopy, the effect of water content on the electrochemical processes occurring during nickel deposition was better understood. At highly negative potentials and depending on water content, Ni growth is halted due to water splitting and formation of a mixed layer of Ni/NiOx(OH)(2(1-x)(ads)). Moreover, under certain conditions, the DES components can also be (electro)chemically reduced at the electrode surface, blocking further three-dimensional growth of the Ni NPs. Hence, a two-dimensional crystalline Ni-containing network can be formed in the interparticle region.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 4.536
Times cited: 27
DOI: 10.1021/acs.jpcc.8b05344
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“Spiral phase plate contrast in optical and electron microscopy”. Juchtmans R, Clark L, Lubk A, Verbeeck J, Physical review A 94, 023838 (2016). http://doi.org/10.1103/PhysRevA.94.023838
Abstract: The use of phase plates in the back focal plane of a microscope is a well-established technique in optical microscopy to increase the contrast of weakly interacting samples and is gaining interest in electron microscopy as well. In this paper we study the spiral phase plate (SPP), also called helical, vortex, or two-dimensional Hilbert phase plate, which adds an angularly dependent phase of the form exp(iℓϕk) to the exit wave in Fourier space. In the limit of large collection angles, we analytically calculate that the average of a pair of l=+-1
SPP filtered images is directly proportional to the gradient squared of the exit wave, explaining the edge contrast previously seen in optical SPP work. We discuss the difference between a clockwise-anticlockwise pair of SPP filtered images and derive conditions under which the modulus of the wave's gradient can be seen directly from one SPP filtered image. This work provides the theoretical background to interpret images obtained with a SPP, thereby opening new perspectives for new experiments to study, for example, magnetic materials in an electron microscope.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.925
Times cited: 10
DOI: 10.1103/PhysRevA.94.023838
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“Dielectric barrier discharges used for the conversion of greenhouse gases: modeling the plasma chemistry by fluid simulations”. De Bie C, Martens T, van Dijk J, Paulussen S, Verheyde B, Corthals S, Bogaerts A, Plasma sources science and technology 20, 024008 (2011). http://doi.org/10.1088/0963-0252/20/2/024008
Abstract: The conversion of methane to value-added chemicals and fuels is considered to be one of the challenges of the 21st century. In this paper we study, by means of fluid modeling, the conversion of methane to higher hydrocarbons or oxygenates by partial oxidation with CO2 or O2 in a dielectric barrier discharge. Sixty-nine different plasma species (electrons, ions, molecules, radicals) are included in the model, as well as a comprehensive set of chemical reactions. The calculation results presented in this paper include the conversion of the reactants and the yields of the reaction products as a function of residence time in the reactor, for different gas mixing ratios. Syngas (i.e. H2 + CO) and higher hydrocarbons (C2Hx) are typically found to be important reaction products.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3.302
Times cited: 38
DOI: 10.1088/0963-0252/20/2/024008
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“Superconducting vortex state in a mesoscopic disk containing a blind hole”. Berdiyorov GR, Milošević, MV, Baelus BJ, Peeters FM, Physical review : B : condensed matter and materials physics 70, 024508 (2004). http://doi.org/10.1103/PhysRevB.70.024508
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 39
DOI: 10.1103/PhysRevB.70.024508
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“Superconducting properties of mesoscopic cylinders with enhanced surface superconductivity”. Baelus BJ, Yampolskii SV, Peeters FM, Montevecchi E, Indekeu JO, Physical review : B : condensed matter and materials physics 65, 024510 (2002). http://doi.org/10.1103/PhysRevB.65.024510
Abstract: The superconducting state of an infinitely long superconducting cylinder surrounded by a medium which enhances its superconductivity near the boundary is studied within the nonlinear Ginzburg-Landau theory. This enhancement can be due to the proximity of another superconductor or due to surface treatment. Quantities such as the free energy, the magnetization and the Cooper-pair density are calculated. Phase diagrams are obtained to investigate how the critical field and the critical temperature depend on this surface enhancement for different values of the Ginzburg-Landau parameter kappa. Increasing the superconductivity near the surface leads to higher critical fields and critical temperatures. For small cylinder diameters only giant vortex states nucleate, while for larger cylinders multivortices can nucleate. The stability of these multivortex states also depends on the surface enhancement. For type-I superconductors we found the remarkable result that for a range of values of the surface extrapolation length the superconductor can transit from the Meissner state into superconducting states with vorticity L > 1. Such a behavior is not found for the case of large kappa, i.e., type-II superconductivity,
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 13
DOI: 10.1103/PhysRevB.65.024510
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“Influence of surface defects on vortex penetration and expulsion in mesoscopic superconductors”. Baelus BJ, Kadowaki K, Peeters FM, Physical review : B : condensed matter and materials physics 71, 024514 (2005). http://doi.org/10.1103/PhysRevB.71.024514
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.836
Times cited: 27
DOI: 10.1103/PhysRevB.71.024514
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