Lumbeeck G (2019) Mechanisms of nano-plasticity in as-deposited and hydrided nanocrystalline Pd and Ni thin films. 130 p
Keywords: Doctoral thesis; Electron microscopy for materials research (EMAT)
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Anđ,elković, M (2019) O(N) numerical methods for investigating graphene heterostructures and moiré patterns. 207 p
Keywords: Doctoral thesis; Condensed Matter Theory (CMT)
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Chuon S (2019) Simulation numérique multi-échelles du procédé de dépôt par pulvérisation cathodique magnétron. 137 p
Keywords: Doctoral thesis; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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“Electroactivity of superoxide anion in aqueous phosphate buffers analyzed with platinized microelectrodes”. Lefrancois P, Girard-Sahun F, Badets V, Clement F, Arbault S, Electroanalysis (2020). http://doi.org/10.1002/ELAN.202060456
Abstract: The reactivity of platinized ultramicroelectrodes (Pt-black UMEs) towards superoxide anion O-2(.-), an unstable Reactive Oxygen Species (ROS), and its relatives, H2O2 and O-2, was studied. Voltammetric studies in PBS demonstrate that Pt-black UMEs provide: i) a well-resolved reversible redox signature for O-2(.-) detected in both alkaline and physiological buffers (pH 12 and 7.4); ii) irreversible oxidation and reduction waves for H2O2 at pH 7.4. The oxygen reduction reaction (ORR) at Pt-black surfaces solely yields H2O2 (2 electrons/2 H+) at physiological pH. Consequently, Pt-black UMEs allow to sense different ROS including superoxide anion for future biomedical or physico-chemical investigations.
Keywords: A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
Impact Factor: 3
DOI: 10.1002/ELAN.202060456
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Vermeiren V (2020) Chemical kinetics modeling of non-equilibrium and thermal effects in vibrationally active CO2 plasmas. 207 p
Keywords: Doctoral thesis; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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Nematollahi P (2020) Density functional theory calculations for understanding gas conversion reactions on single metal atom embedded carbon-based nanocatalysts. 173 p
Keywords: Doctoral thesis; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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“Gold-sputtered microelectrodes with built-in gold reference and counter electrodes for electrochemical DNA detection”. Thiruvottriyur Shanmugam S, Trashin S, De Wael K, Analyst (2020). http://doi.org/10.1039/D0AN01387K
Abstract: Gold-sputtered microelectrodes with built-in gold reference and counter electrodes represent a promising platform for the development of disposable DNA sensors. Pretreating gold electrode surfaces and immobilization of DNA thereon is commonly employed in biosensing applications. However, with no scientific or practical guidelines to prepare a DNA sensor using these miniature gold-sputtered microelectrodes, cleaning and immobilization steps need to be systematically optimized and updated. In this work, we present efficient cleaning and modification of miniaturized gold-sputtered microelectrodes with thiolated DNA probes for DNA detection. Additional discussions on subtleties and nuances involved at each stage of pretreating and modifying gold-sputtered microelectrodes are included to present a robust, well-founded protocol. It was evident that the insights on cleaning polycrystalline gold disk electrodes with a benchmark electrode surface for DNA sensors, cannot be transferred to clean these miniature gold-sputtered microelectrodes. Therefore, a comparison between five different cleaning protocols was made to find the optimal one for gold-sputtered microelectrodes. Additionally, two principally different immobilization techniques for gold-sputtered microelectrode modification with thiolated ssDNA were compared i.e., immobilization through passive chemisorption and potential perturbation were compared in terms of thiol-specific attachment and thiol-unspecific adsorption through nitrogenous bases. The hybridization performance of these prepared electrodes was characterized by their sensitive complementary DNA capturing ability, detected by a standard alkaline phosphatase assay. Immobilization through passive chemisorption proved to be efficient in capturing the complementary target DNA with a detection limit of 0.14 nM and sensitivity of 9.38 A M−1 cm2. In general, this work presents a comprehensive understanding of cleaning, modification and performance of gold-sputtered microelectrodes with built-in gold reference and counter electrodes for both fundamental investigations and practical DNA sensing applications.
Keywords: A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 4.2
DOI: 10.1039/D0AN01387K
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De Jong M (2020) A highly accurate portable electrochemical sensor for cocaine : from methodology to testing in the field. 263 p
Keywords: Doctoral thesis; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Ik drink (geen) afval! Een exploratieve studie naar socio-demografische verschillen in publieke steun voor het hergebruik van afvalwater in Vlaanderen”. Geerts R, Vandermoere F, Halet D, Van Winckel T, Joos P, Van Den Steen K, Van Meenen E, Blust R, Vlaeminck SE, Vlaams tijdschrift voor overheidsmanagement , 51 (2020)
Abstract: In een context van stijgende waterschaarste verkennen wij, naar ons weten voor het eerst in Vlaanderen, publieke steun voor de behandeling en het hergebruik van afvalwater als drinkwater. Vlaanderen is vandaag een van de weinige regio’s waar afvalwater reeds gerecycleerd wordt voor drinkwaterdoeleinden. Dit gebeurt op kleinschalig niveau en de uitbreiding hiervan is vandaag een van de Vlaamse beleidsdoelstellingen. Internationale voorbeelden toonden echter dat een gebrek aan publieke steun een aanzienlijk obstakel kan zijn. Vaak worden gezondheids- en veiligheidsbezorgdheden aangehaald als oorzaak voor het beperkte draagvlak. Minder is geweten over de socio-demografische distributie van dit draagvlak. Daarbovenop blijft er onduidelijkheid over de samenhang tussen socio-demografische kenmerken en gezondheids- en veiligheidsbezorgdheden. Met behulp van een enquête uitgevoerd in Vlaanderen (N=2309), bestudeerden wij ten eerste deze socio-demografische verschillen op basis van bivariate associaties (gender, opleidingsniveau, leeftijd en woonplaats). Ten tweede construeerden we een padmodel om te onderzoeken of deze verschillen verklaard kunnen worden aan de hand van gezondheids- en veiligheidsbezorgdheden. Onze resultaten toonden dat publieke steun voor afvalwaterhergebruik voor drinkwaterdoeleinden in Vlaanderen beperkt is. Het draagvlak was het laagst bij oudere mensen, vrouwen, lager geschoolde groepen en mensen die niet in de Provincie Antwerpen wonen. Voor een groot deel konden socio-demografische verschillen verklaard worden door hogere gezondheids- en veiligheidsbezorgdheden bij vrouwen, lager geschoolden en mensen uit West- en Oost-Vlaanderen. Dit suggereert een gebrek aan vertrouwen in waterexperts en -technologie bij bepaalde socio-demografische groepen, wat zich vertaalt in een verminderde publieke steun voor afvalwaterhergebruik. Op basis van deze bevindingen bespreken we een aantal potentiële actiestrategieën om publieke oppositie te anticiperen en proactief publieke steun te verwerven via doelgerichte (risico)communicatie.
Keywords: A1 Journal article; Sociology; Sustainable Energy, Air and Water Technology (DuEL); Centre for Research on Environmental and Social Change
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Bafekry A (2020) Investigation of the effects of defects and impurities on nanostructures consisting of Group IV and V elements using First-principles calculations. 126 p
Keywords: Doctoral thesis; Condensed Matter Theory (CMT)
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Conti S (2020) Multi-band superfluidity and BEC-BCS crossover in novel ultrathin materials. 123 p
Keywords: Doctoral thesis; Sociology; History; Condensed Matter Theory (CMT)
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Zhang H (2020) Optical diagnostics of spatiotemporal evolution characteristics of nanosecond laser-induced plasma in gases. 117 p
Keywords: Doctoral thesis; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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Heijkers S (2020) Plasma chemistry modelling for CO2 and CH4 conversion in various plasma types. 316 p
Keywords: Doctoral thesis; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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Eliaerts J (2020) Qualitative and quantitative determination of cocaine using mid-infrared spectroscopy and chemometrics. 184 p
Keywords: Doctoral thesis; Law; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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Vanherck J (2020) Spontaneous and induced magnetisation in two-dimensional and bulk Heisenberg ferromagnets : a quantum mechanical treatment. 160 p
Keywords: Doctoral thesis; Condensed Matter Theory (CMT)
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Hendrickx M (2020) Study of the effect of cation substitution on the local structure and the properties of perovskites and Li-ion battery cathode materials. 208 p
Keywords: Doctoral thesis; Electron microscopy for materials research (EMAT)
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Milagres de Oliveira T (2020) Three-dimensional characterisation of nanomaterials : from model-like systems to real nanostructures. 230 p
Keywords: Doctoral thesis; Electron microscopy for materials research (EMAT)
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Vanrompay H (2020) Toward fast and dose efficient electron tomography. 207 p
Keywords: Doctoral thesis; Electron microscopy for materials research (EMAT)
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“Transposing testing from lab to on-site environment : a case of cocaine powder sampling”. Van Loon J, De Jong M, De Wael K, Du Bois E, (2020)
Abstract: This paper reports on the transition process to convert a specific lab technique to the on-site, real-life environment. Bringing a lab test to an on-site environment involves many difficulties regarding to the context, people skills and environmental support. Within this project, a case about sampling for an electrochemical measurement, was investigated as a basis to reason upon some general conclusions related to the process of transposing lab-tests to an on-site environment. The current lab test was analysed and compared with a focus group discussion with future users. Based on the findings, assumptions for the new sampling technique in the specific case were formulated. New low-tech methods to achieve the sampling were extensively tested and verified. Starting from this chosen case an argumentation was set up to generalise the conclusions, by reasoning on other cases of products that already passed this transition to the field. Based on a comparison, we could discuss that the selected parameters related to impact of the context environment, of the people that should handle the tests, related to the reasons for transposing the technology, and related to the technology that will be transposed to the on-site environment, were of importance of almost all cases and can therefore be considered as context-independent and related to the transfer to on-site testing.
Keywords: P3 Proceeding; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Product development
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“Van der Waals heterostructures of MoS₂, and Janus MoSSe monolayers on graphitic boron-carbon-nitride (BC₃, C₃N, C₃N₄, and C₄N₃) nanosheets: a first-principles study”. Bafekry A, Yagmurcukardes M, Akgenc B, Ghergherehchi M, Nguyen C, Journal Of Physics D-Applied Physics , 1 (2020). http://doi.org/10.1088/1361-6463/AB876C
Abstract: In this work, we extensively investigate the structural and electronic properties of van der Waals heterostructures (HTs) constructed by MoS${2}$/$BC3$, MoS${2}$/$C3N$, MoS${2}$/$C3N4$, MoS${2}$/$C4N3$ and those using Janus MoSSe instead of MoS$2$ by performing density functional theory calculations. The electronic band structure calculations and the corresponding partial density of states reveal that the significant changes are driven by quite strong layer-layer interaction between the constitutive layers. Our results show that although all monolayers are semiconductors as free-standing layers, the MoS${2}$/$C3N$ and MoS${2}$/$C4N3$ bilayer HTs display metallic behavior as a consequence of transfer of charge carriers between two constituent layers. In addition, it is found that in MoSSe/$C3N$ bilayer HT, the degree of metallicity is affected by the interface chalcogen atom type when Se atoms are facing to $C3N$ layer, the overlap of the bands around the Fermi level is smaller. Moreover, the half-metallic magnetic $C4N3$ is shown to form magnetic half-metallic trilayer HT with MoS$2$ independent of the stacking sequence, i.e. whether it is sandwiched or two $C4N3$ layer encapsulate MoS$2$ layer. We further analyze the trilayer HTs in which MoS$2$ is encapsulated by two different monolayers and it is revealed that at least with one magnetic monolayer, it is possible to construct a magnetic trilayer. While the trilayer of $C4N3$/MoS${2}$/$BC3$ and $C4N3$/MoS${2}$/$C3N4$ exhibit half-metallic characteristics, $C4N3$/MoS${_2}$/$C3$N possesses a magnetic metallic ground state. Overall, our results reveal that holly structures of BCN crystals are suitable for heterostructure formation even over van der Waals type interaction which significantly changes electronic nature of the constituent layers.
Keywords: A1 Journal article; Condensed Matter Theory (CMT)
Impact Factor: 3.4
DOI: 10.1088/1361-6463/AB876C
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Rivera Julio J (2021) Cálculos ab initio de sistemas 2D y de baja dimensionalidad. 137 p
Keywords: Doctoral thesis; Condensed Matter Theory (CMT)
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Jafarzadeh A (2020) First-principle studies of plasma-catalyst interactions for greenhouse gas conversion. 163 p
Keywords: Doctoral thesis; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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Ranjbar S (2020) Mathematical model of plasma therapy on bacterial growth. 95 p
Keywords: Doctoral thesis; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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“Modeling the CO2 dissociation in pulsed atmospheric-pressure discharge”. Kolev S, Paunska T, Trenchev G, Bogaerts A, Technologies , 012007 (2020). http://doi.org/10.1088/1742-6596/1492/1/012007
Abstract: CO2 dissociation and its subsequent conversion into added-value chemicals is a promising strategy for recycling CO2 gas into reusable products. One of the possible methods is direct plasma-induced dissociation. In this work we study the efficiency of CO2 dissociation in pulsed atmospheric-pressure gas discharge between two conducting electrodes by a 0-D numerical plasma model. The purpose of the study is to provide results on the optimal conditions of CO2 conversion with respect to the energy efficiency and dissociation by varying the maximum power density value and the pulse length. The power density is directly related to the discharge current and the reduced electric field in the discharge. We consider pulse lengths in the range from hundreds of nanosecond up to milliseconds. The results obtained show that the dissociation degree and energy efficiency are sensitive to the pulse length (duration) and the power density, so that a considerable improvement of the discharge performance can be achieved by fine-tuning these parameters. The study is intended to provide guidance in designing an experimental set-up and a power supply with the characteristics necessary to achieve optimal conversion.
Keywords: P1 Proceeding; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
DOI: 10.1088/1742-6596/1492/1/012007
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Uytdenhouwen Y (2020) Tuning the performance of a DBD plasma reactor for CO2 reforming. 303 p
Keywords: Doctoral thesis; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT)
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“Enhancing the hydrogen evolution properties of kesterite absorber by Si-doping in the surface of CZTS thin film”. Vishwakarma M, Kumar M, Hendrickx M, Hadermann J, Singh AP, Batra Y, Mehta BR, Advanced Materials Interfaces , 2002124 (2021). http://doi.org/10.1002/ADMI.202002124
Abstract: In this work, the effects of Si-doping in Cu2ZnSnS4 are examined computationally and experimentally. The density functional theory calculations show that an increasing concentration of Si (from x = 0 to x = 1) yields a band gap rise due to shifting of the conduction band minimum towards higher energy states in the Cu2Zn(Sn1-xSix)S-4. CZTSiS thin film prepared by co-sputtering process shows Cu2Zn(Sn1-xSix)S-4 (Si-rich) and Cu2ZnSnS4 (S-rich) kesterite phases on the surface and in the bulk of the sample, respectively. A significant change in surface electronic properties is observed in CZTSiS thin film. Si-doping in CZTS inverts the band bending at grain-boundaries from downward to upward and the Fermi level of CZTSiS shifts upward. Further, the coating of the CdS and ZnO layer improves the photocurrent to approximate to 5.57 mA cm(-2) at -0.41 V-RHE in the CZTSiS/CdS/ZnO sample, which is 2.39 times higher than that of pure CZTS. The flat band potential increases from CZTS approximate to 0.43 V-RHE to CZTSiS/CdS/ZnO approximate to 1.31 V-RHE indicating the faster carrier separation process at the electrode-electrolyte interface in the latter sample. CdS/ZnO layers over CZTSiS significantly reduce the charge transfer resistance at the semiconductor-electrolyte interface.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 4.279
DOI: 10.1002/ADMI.202002124
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Skorikov A (2021) Fast approaches for investigating 3D elemental distribution in nanomaterials. 143 p
Keywords: Doctoral thesis; Electron microscopy for materials research (EMAT)
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Pedrazo Tardajos A (2021) Advanced graphene supports for 3D in situ transmission electron microscopy. 247 p
Abstract: Transmission electron microscopy (TEM) is an ideal tool to investigate nanomaterials. The information from TEM experiments allows us to link the structure and composition of nanomaterials to their intrinsic physical properties. However, despite the significant evolution of the TEM field during the last two decades, major progress is still possible through the development of optimal TEM techniques and supports. The results presented in this thesis focus on the optimization of sample supports and their application. Among the different options, graphene has previously been reported as useful sample support for electron microscopy due to its unparalleled properties, for example, it is the thinnest known support and provides a protective effect to the sample under investigation. Unfortunately, commercial graphene grids show poor quality, in terms of intactness and cleanness, inhibiting their wide application within the field. Therefore, this thesis focuses on the application of optimized graphene TEM grids, obtained by transferring high quality graphene using an advanced procedure. This improvement on the transfer has enabled the visualization of materials with low contrast and high sensitivity towards the electron beam, such as surface ligands capping gold nanoparticles or metal halide perovskites. Furthermore, the implemented protocol is not only of interest for conventional TEM grids but also a major benefit for in situ TEM studies, where the sample is investigated in real time under certain stimuli. Hence, the same graphene transfer technology can be also applied to advanced in situ MEMS holders dedicated for both heating and gas experiments, where the thickness and insulating nature of the silicon nitride (Si3N4) support may hamper some applications. By engineering periodic arrays of holes in their Si3N4 membrane by focused ion beam, onto which the graphene is transferred, it has been possible to get proof-of-concept 3D in situ investigations of heat-induced morphological and compositional transformations of complex nanosystems. As an example, it has enabled the investigation of the possible phase-transition of metal halide perovskites upon heating using 2D and 3D structural characterization. Moreover, it has allowed the study of in situ three-dimensional nanoparticle dynamics during gas phase catalysis as well as the first steps that would lead towards the design and creation of the first Graphene Gas Cell. Consequently, implementation of the advanced graphene transfer technology described in this thesis is envisaged to impact a broad range of future experiments.
Keywords: Doctoral thesis; Electron microscopy for materials research (EMAT)
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Skorikov A, Heyvaert W, Albrecht W, Pelt DM, Bals S (2021) EMAT Simulated 3D Nanoparticle Structures Dataset
Abstract: This dataset contains 1000 simulated nanoparticle-like 3D structures and noisy EDX-like elemental maps based on them. These data are intended to be used for quantitative analysis of data processing methods in (EDX) tomography of nanoparticles and training the data-driven approaches for these tasks. The dataset is structured as follows: voxel_data/clean 3D voxel grid representation of the simulated nanoparticles. Voxel intensities are adjusted so that the total intensity equals 103. All 3D structures have unique identifiers in 0..999 range. The data derived from a 3D structure preserves this unique identifier. sinograms/clean Tilt series of projection images obtained from the corresponding 3D structures over an angular range of -75..75 degrees with a tilt step of 10 degrees to simulate a typical tilt series used in EDX tomography. Total intensity in each projection image equals 103. sinograms/noisy Tilt series of projection images corrupted with Poisson noise and an additional spatially uniform background noise. projections/clean Projection images extracted from the clean tilt series at 0 degrees tilt angle. projections/noisy Projection images extracted from the noisy tilt series at 0 degrees tilt angle. images/clean Visualizations of the clean projections as PNG images with the intensity range adjusted to 0..255 images/noisy Visualizations of the noisy projections as PNG images with the intensity range adjusted to 0..255
Keywords: Dataset; Electron microscopy for materials research (EMAT)
DOI: 10.5281/zenodo.4580545
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Du K (2021) In situ TEM study on the manipulation of ferroelectrics. 91 p
Abstract: The strong correlated oxide systems attract a lot of attentions of scientists recently, the coexistence and interplay between various degrees of freedom, such as charge, spin and orbital, has been demonstrated to induce some fancy physical properties and phenomenon, including metal-insulator transition, high temperature superconductivity, colossal magnetoresistance. As a part of the strong correlated oxide systems, the ferroelectrics is abundant in both physical properties and application. First, if the electric dipole continuously rotating around a stable core then a topological structure is produced. If people could manipulate the topological structure and simultaneously observe the structure evolution, with external field applied on the topological structure, then it is very likely for such kind of ferroelectrics to be the next generation of storage, for it is reported to need low power input and produce high density of storage. In the other hand, in solids, charge polarity can one-to-one correspond to spin polarity phenomenologically, such as ferroelectricity and ferromagnetism, antiferroelectricity and antiferromagnetism, but ferrielectricity and ferrimagnetism kept telling a disparate story in microscopic level. The claimed “ferrielectrics” in existing research is equivalent to ferroelectric ones, thus the findings of such a real irreducible solids would complete the last piece of the ferroelectrics family. While solving the above two questions remain challengeable: the size of topological structure is small (typically below 10 nm), general characterization methods are insufficient for such high demand on space resolution, not to mention manipulating and observing its dynamic behavior at an atomic level. Here, employing the spherical aberration corrected electron microscope, we applied external field (heating and bias) on ferroelectrics. Combined with high-end characterization methods including the high-angle annular dark field (HAADF-STEM) image, Electron Energy Loss Spectroscopy (EELS) and integrated differential phase contrast (iDPC), the dynamic evolution of ferroelectrics are observed and analyzed. The main findings of this paper could be concluded as listed here: (1) PbTiO3(001)// SrTiO3(001) is grown on DyScO3 and SrRuO3 by pusled laser deposition, the atomical EDS mapping results reveal that the interface between PTO and STO is atomically sharp. Increasing the thickness of PTO from 1 uc to 21 uc, the topological structure wihtin PTO layer would transform from a/c domain to wave, vortex and finally flux closure domain. The geometric phase analysis results (GPA) reveal that above topological structures are corresponding to various strain. (2) Combined with in-situ biasing holder, the electric bias was applied on polar vortex, and it evolved from vortex (0 V) to polar wave (2 V) and finally polar down (5 V). EELS analysis was performed and we find that negative charge is gathered at vortex core, which turns the Ti4+ to Ti3+ there. The oxygen vacancy at negative polarization surface and the negative charge at the positive polarization surface realized the polarization screening of polar down domain. (3) Through the atomic inspection and analysis on lattice structure of BaFe2Se3, the near ladders within single unit are found to be different in degree of tetramerization, thus leading to a residual polarization along the a-axis. The further in-situ heating and biasing experiment was conducted on BaFe2Se3, and the strong and weak ladders are proved to be independent for their behavior under external field. This findings distinguishes ferrielectrics from ferroelectrics in solids.
Keywords: Doctoral thesis; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
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