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Author Pascucci, F.
Title Superfluidity in exciton bilayer systems : Josephson effect and collective modes as definitive identification-markers Type Doctoral thesis
Year 2024 Publication Abbreviated Journal
Volume Issue Pages xiii, 126 p.
Keywords Doctoral thesis; Theory of quantum systems and complex systems; Condensed Matter Theory (CMT)
Abstract This thesis explores superfluidity in exciton bilayer systems, semiconductor structures with two thin conducting layers, one doped with electrons and the other with holes, separated by a few nanometers. Theoretical predictions suggest these systems can exhibit superfluid, supersolid, exciton normal solid, and Wigner crystal phases. Identifying clear markers of superfluidity is crucial due to experimental challenges in confirming excitonic superfluidity. This thesis focuses on two phenomena: the Josephson effect and density collective modes. For the Josephson effect, we propose an exciton bilayer Josephson junction in double monolayer Transition Metal Dichalcogenides. We suggest using the Shapiro method to measure the exciton Josephson current and propose fabricating the device with a tunable potential-barrier height. In low potential-barrier regions, the exciton superfluid flows over the barrier, while in high potential-barrier regions, flow is driven by quantum tunnelling. This helps delineate the boundary between Bose-Einstein Condensate (BEC) and BCS-BEC crossover regimes. For density collective modes, we examine low-temperature behaviour to identify the normal-superfluid transition as a function of density. In the normal state at high density, the system exhibits low-energy optic and acoustic modes. As density decreases, entering the superfluid phase, the response changes, with the superfluid gap blocking these modes. We expect pair-breaking collective modes to appear at the onset of exciton superfluidity due to the Coulomb interaction. Our theoretical model developed using a path-integral approach and the Hartree-Fock approximation, includes screening and intralayer correlations. We calculate gap and number equations governing superfluid phase behaviour, showing that intralayer correlations enhance screening, especially in the BCS-BEC crossover regime. This leads to a reduced superfluid gap, a shift in the BEC to BCS-BEC crossover boundary to lower densities, and the disappearance of a predicted minimum in electron-hole pair size. This study advances the understanding of superfluidity in exciton bilayer systems, providing theoretical predictions and experimental proposals. By identifying clear markers of superfluidity, this work contributes to the broader effort of realizing and characterizing excitonic condensed phases in realistic systems.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2024-09-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number (down) UA @ admin @ c:irua:207852 Serial 9318
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Author Borah, R.; Raj A.G., K.; Verbruggen, S.W.
Title Flow-by membraneless electrolyzer designs : a macroporous flow dividing mesh enhances maximum allowable electrode length Type A1 Journal article
Year 2024 Publication Fuel Abbreviated Journal
Volume 377 Issue Pages 132779-15
Keywords A1 Journal article; Engineering sciences. Technology; Antwerp engineering, PhotoElectroChemistry & Sensing (A-PECS)
Abstract The membraneless electrolyzer design promises a low-cost and robust electrolyzer technology, eliminating the disadvantages associated with the membranes/diaphragms in conventional electrolyzers. Flow-by membraneless electrolyzers exploit the Segré–Silberberg effect, where the electrolyte flow between parallel face-to-face cathode and anode forbids the evolving hydrogen and oxygen bubbles to cross over to the other side, while still allowing ionic currents between the electrodes to pass. The removal of the membrane from traditional electrolyzers, and instead exploiting the electrolyte flow itself to function as a gas separator also imposes certain requirements, namely: 1) upward laminar flow and, 2) vertically aligned electrodes. Given the upper limit of the laminar flow regime (Reynolds number, Re ∼ 1800), the admissible length of both vertically aligned electrodes is constrained by the production volume of H2 and O2 at both electrodes. Beyond a certain production rate the evolving gas plume increases in thickness until it reaches the central line dividing the channel between the electrodes. From that point onwards, flow mediated separation of both gases becomes practically impossible. In this work the design constraints of membraneless electrolyzers are investigated by combined multiphysics modeling and mass-balance analysis. Next, a macroporous flow dividing mesh is introduced in the design that allows seamless ionic flow between the electrodes while facilitating a higher electrolyte velocity in the laminar regime. This in turn enables to increase the maximum electrode length (or height) by >50 %. The model based analysis provides important guidelines for further development of membraneless electrolyzers, significantly reducing future experimental optimization efforts.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2024-08-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0016-2361 ISBN Additional Links UA library record
Impact Factor 7.4 Times cited Open Access
Notes Approved Most recent IF: 7.4; 2024 IF: 4.601
Call Number (down) UA @ admin @ c:irua:207729 Serial 9291
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Author Ghosh, S.; Pradhan, B.; Bandyopadhyay, A.; Skvortsova, I.; Zhang, Y.; Sternemann, C.; Paulus, M.; Bals, S.; Hofkens, J.; Karki, K.J.; Materny, A.
Title Rashba-type band splitting effect in 2D (PEA)₂PbI₄ perovskites and its impact on exciton-phonon coupling Type A1 Journal article
Year 2024 Publication The journal of physical chemistry letters Abbreviated Journal
Volume 15 Issue 31 Pages 7970-7978
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Despite a few recent reports on Rashba effects in two-dimensional (2D) Ruddlesden-Popper (RP) hybrid perovskites, the precise role of organic spacer cations in influencing Rashba band splitting remains unclear. Here, using a combination of temperature-dependent two-photon photoluminescence (2PPL) and time-resolved photoluminescence spectroscopy, alongside density functional theory (DFT) calculations, we contribute to significant insights into the Rashba band splitting found for 2D RP hybrid perovskites. The results demonstrate that the polarity of the organic spacer cation is crucial in inducing structural distortions that lead to Rashba-type band splitting. Our investigations show that the intricate details of the Rashba band splitting occur for organic cations with low polarity but not for more polar ones. Furthermore, we have observed stronger exciton-phonon interactions due to the Rashba-type band splitting effect. These findings clarify the importance of selecting appropriate organic spacer cations to manipulate the electronic properties of 2D perovskites.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=brocade2&SrcAuth=WosAPI&KeyUT=WOS:001280 Publication Date 2024-07-30
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1948-7185 ISBN Additional Links UA library record; WoS full record
Impact Factor 5.7 Times cited Open Access
Notes Approved Most recent IF: 5.7; 2024 IF: 9.353
Call Number (down) UA @ admin @ c:irua:207672 Serial 9313
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Author De Keyser, N.; Broers, F.T.H.; Vanmeert, F.; van Loon, A.; Gabrieli, F.; De Meyer, S.; Gestels, A.; Gonzalez, V.; Hermens, E.; Noble, P.; Meirer, F.; Janssens, K.; Keune, K.
Title Discovery of pararealgar and semi-amorphous pararealgar in Rembrandt's The Night Watch : analytical study and historical contextualization Type A1 Journal article
Year 2024 Publication Heritage science Abbreviated Journal
Volume 12 Issue 1 Pages 237-20
Keywords A1 Journal article; Art; Antwerp X-ray Imaging and Spectroscopy (AXIS)
Abstract This article reports on the discovery of pararealgar and semi-amorphous pararealgar in Rembrandt's masterpiece The Night Watch. A large-scale research project named Operation Night Watch was started in 2019. A variety of non-invasive analytical imaging techniques, together with paint sample research, has provided new information about Rembrandt's pigments, materials, and techniques as well as the current condition of the painting. Macroscopic X-ray fluorescence, macroscopic X-ray powder diffraction and reflectance imaging spectroscopy identified the presence of arsenic sulfide pigments and degradation products of these pigments in the doublet sleeves and embroidered buff coat worn by Lieutenant Willem van Ruytenburch (central figure to the right of Captain Frans Banninck Cocq). Examination by light microscopy of two paint samples taken from this area shows a mixture of large sharp-edged tabular yellow and orange to red pigment particles, and scanning electron microscopy-energy dispersive X-ray analysis identified these particles as containing arsenic and sulfur. Using micro-Raman spectroscopy, the yellow particles were identified as pararealgar, and the orange to red particles as semi-amorphous pararealgar. Synchrotron-based X-ray diffraction allowed visualization of the presence of multiple degradation products associated with arsenic sulfides throughout the paint layer. The discovery of pararealgar and semi-amorphous pararealgar is a new addition to Rembrandt's pigment palette. To contextualize our findings and to hypothesize why, how, and where Rembrandt obtained the pigments, we studied related historical sources. A comprehensive review of historical sources gives insight into the types of artificial arsenic sulfides that were available and suggests that a broader range of arsenic pigments could have been available in Amsterdam in the seventeenth century than previously thought. This is supported by the use of a very similar mixture of pigments by Willem Kalf (1619-1693), a contemporary artist based in Amsterdam. Together with the condition of the particles in the paint cross sections, this brings us to the conclusion that Rembrandt intentionally used pararealgar and semi-amorphous pararealgar, together with lead-tin yellow and vermilion, to create an orange paint.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=brocade2&SrcAuth=WosAPI&KeyUT=WOS:001270 Publication Date 2024-07-11
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2050-7445 ISBN Additional Links UA library record; WoS full record
Impact Factor 2.5 Times cited Open Access
Notes Approved Most recent IF: 2.5; 2024 IF: NA
Call Number (down) UA @ admin @ c:irua:207665 Serial 9284
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Author Pompei, E.; Vlamidis, Y.; Ferbel, L.; Zannier, V.; Rubini, S.; Arenas Esteban, D.; Bals, S.; Marinelli, C.; Pfusterschmied, G.; Leitgeb, M.; Schmid, U.; Heun, S.; Veronesi, S.
Title Functionalization of three-dimensional epitaxial graphene with metal nanoparticles Type A1 Journal article
Year 2024 Publication Nanoscale Abbreviated Journal
Volume 16 Issue 34 Pages 16107-16118
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract We demonstrate the first successful functionalization of epitaxial three-dimensional graphene with metal nanoparticles. The functionalization is obtained by immersing three-dimensional graphene in a nanoparticle colloidal solution. This method is versatile and demonstrated here for gold and palladium, but can be extended to other types of nanoparticles. We have measured the nanoparticle density on the top surface and in the porous layer volume by scanning electron microscopy and scanning transmission electron microscopy. The samples exhibit a wide coverage of nanoparticles with minimal clustering. We demonstrate that high-quality graphene promotes the functionalization, leading to higher nanoparticle density both on the surface and in the pores. X-ray photoelectron spectroscopy shows the absence of contamination after the functionalization process. Moreover, it confirms the thermal stability of the Au- and Pd-functionalized three-dimensional graphene up to 530 degrees C. Our approach opens new avenues for utilizing three-dimensional graphene as a versatile platform for catalytic applications, sensors, and energy storage and conversion. We report a new technique for fabricating metal-functionalized three-dimensional epitaxial graphene on porous SiC. The process is clean and scalable. The fabricated material exhibits high chemical and thermal stability, and versatility.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=brocade2&SrcAuth=WosAPI&KeyUT=WOS:001283 Publication Date 2024-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2040-3364; 2040-3372 ISBN Additional Links UA library record; WoS full record
Impact Factor 6.7 Times cited Open Access
Notes Approved Most recent IF: 6.7; 2024 IF: 7.367
Call Number (down) UA @ admin @ c:irua:207655 Serial 9292
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Author Yari, S.; Bird, L.; Rahimisheikh, S.; Reis, A.C.; Mohammad, M.; Hadermann, J.; Robinson, J.; Shearing, P.R.; Safari, M.
Title Probing charge transport and microstructural attributes in solvent- versus water-based electrodes with a spotlight on Li-S battery cathode Type A1 Journal article
Year 2024 Publication Advanced energy materials Abbreviated Journal
Volume Issue Pages 2402163
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract In the quest for environmentally benign battery technologies, this study examines the microstructural and transport properties of water-processed electrodes and compares them to conventionally formulated electrodes using the toxic solvent, N-Methyl-2-pyrrolidone (NMP). Special focus is placed on sulfur electrodes utilized in lithium-sulfur batteries for their sustainability and compatibility with diverse binder/solvent systems. The characterization of the electrodes by X-ray micro-computed tomography reveals that in polyvinylidene fluoride (PVDF) Lithium bis(trifluoromethanesulfonyl)imide/NMP, sulfur particles tend to remain in large clusters but break down into finer particles in carboxymethyl cellulose-styrene butadiene rubber (CMC-SBR)/water and lithium polyacrylate (LiPAA)/water dispersions. The findings reveal that in the water-based electrodes, the binder properties dictate the spatial arrangement of carbon particles, resulting in either thick aggregates with short-range connectivity or thin films with long-range connectivity among sulfur particles. Additionally, cracking is found to be particularly prominent in thicker water-based electrodes, propagating especially in regions with larger particle agglomerates and often extending to cause local delamination of the electrodes. These microstructural details are shown to significantly impact the tortuosity and contact resistance of the sulfur electrodes and thereby affecting the cycling performance of the Li-S battery cells. The choice of solvent and binder is crucial in determining particle surface charge, which directly influences active material dispersion and carbon-binder arrangement within the battery porous electrodes. This, in turn, affects ionic and electronic transport properties, ultimately impacting electrochemical performance. Meticulous engineering of the slurry to control these factors is essential for efficient and sustainable water-based electrode processing. image
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=brocade2&SrcAuth=WosAPI&KeyUT=WOS:001291 Publication Date 2024-08-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1614-6832; 1614-6840 ISBN Additional Links UA library record; WoS full record
Impact Factor 27.8 Times cited Open Access
Notes Approved Most recent IF: 27.8; 2024 IF: 16.721
Call Number (down) UA @ admin @ c:irua:207624 Serial 9311
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Author Cheng, X.; Xu, W.; Wen, H.; Zhang, J.; Zhang, H.; Li, H.; Peeters, F.M.
Title Key electronic parameters of 2H-stacking bilayer MoS₂ on sapphire substrate determined by terahertz magneto-optical measurement in Faraday geometry Type A1 Journal article
Year 2024 Publication Frontiers of physics Abbreviated Journal
Volume 19 Issue 6 Pages 63204-63209
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Bilayer (BL) transition metal dichalcogenides (TMDs) are important materials in valleytronics and twistronics. Here we study terahertz (THz) magneto-optical (MO) properties of n-type 2H-stacking BL molybdenum sulfide (MoS2) on sapphire substrate grown by chemical vapor deposition. The AFM, Raman spectroscopy and photoluminescence are used for characterization of the samples. Applying THz time-domain spectroscopy (TDS), in combination with polarization test and the presence of magnetic field in Faraday geometry, THz MO transmissions through the sample are measured from 0 to 8 T at 80 K. The complex right- and left-handed circular MO conductivities for 2H-stacking BL MoS2 are obtained. Through fitting the experimental results with theoretical formula of MO conductivities for an electron gas, generalized by us previously through the inclusion of photon-induced electronic backscattering effect, we are able to determine magneto-optically the key electronic parameters of BL MoS2, such as the electron density n(e), the electronic relaxation time tau, the electronic localization factor c and, particularly, the effective electron mass m* around Q-point in between the K- and Gamma-point in the electronic band structure. The dependence of these parameters upon magnetic field is examined and analyzed. This is a pioneering experimental work to measure m* around the Q-point in 2H-stacking BL MoS2 and the experimental value is very close to that obtained theoretically. We find that n(e)/tau/ divided by c divided by /m* in 2H-stacking BL MoS2 decreases/increases/decreases/increases with increasing magnetic field. The results obtained from this study can be benefit to us in gaining an in-depth understanding of the electronic and optoelectronic properties of BL TMD systems.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=brocade2&SrcAuth=WosAPI&KeyUT=WOS:001271 Publication Date 2024-07-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2095-0462; 2095-0470 ISBN Additional Links UA library record; WoS full record
Impact Factor 7.5 Times cited Open Access
Notes Approved Most recent IF: 7.5; 2024 IF: 2.579
Call Number (down) UA @ admin @ c:irua:207600 Serial 9300
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Author Shafiei, M.; Fazileh, F.; Peeters, F.M.; Milošević, M.V.
Title Tuning the quantum phase transition of an ultrathin magnetic topological insulator Type A1 Journal article
Year 2024 Publication Physical review materials Abbreviated Journal
Volume 8 Issue 7 Pages 074201-74208
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We explore the effect of thickness, magnetization direction, strain, and gating on the topological quantum phase transition of a thin-film magnetic topological insulator. Reducing the film thickness to the ultrathin regime couples the edge states on the two surfaces, opening a gap known as the hybridization gap, and causing a phase transition from a topological insulator to a normal insulator (NI). An out-of-plane/in-plane magnetization of size proportional to the hybridization gap triggers a phase transition from a normal insulator state to a quantum anomalous Hall (QAH)/semimetal state. A magnetization tilt by angle 0 from the out-of-plane axis influences the topological phase transition in a way that for sufficiently large 0, no phase transition from NI to QAH can be observed regardless of the sample thickness or magnetization, and for 0 close to pi /2 the system transits to a semimetal phase. Furthermore, we demonstrate that compressive/tensile strain can be used to decrease/increase the magnetization threshold for the topological phase transition. Finally, we reveal the effect of a vertical potential acting on the film, be it due to the substrate or applied gating, which breaks inversion symmetry and raises the magnetization threshold for the transition from NI to QAH state.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=brocade2&SrcAuth=WosAPI&KeyUT=WOS:001281 Publication Date 2024-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2475-9953 ISBN Additional Links UA library record; WoS full record
Impact Factor 3.4 Times cited Open Access
Notes Approved Most recent IF: 3.4; 2024 IF: NA
Call Number (down) UA @ admin @ c:irua:207598 Serial 9324
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Author Kandemir, Z.; D'Amico, P.; Sesti, G.; Cardoso, C.; Milošević, M.V.; Sevik, C.
Title Optical properties of metallic MXene multilayers through advanced first-principles calculations Type A1 Journal article
Year 2024 Publication Physical review materials Abbreviated Journal
Volume 8 Issue 7 Pages 075201-75210
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Having a strong electromagnetic absorption, MXene multilayers are readily envisaged for applications in electromagnetic shields and related prospective technology. However, an ab initio characterization of the optical properties of MXenes is still lacking, due in part to major difficulties with the treatment of metallicity in the first-principles approaches. Here we addressed the latter challenge, after a careful treatment of intraband transitions, to present a thorough analysis of the electronic and optical properties of a selected set of metallic MXene layers based on density functional theory (DFT) and many-body perturbation theory calculations. Our results reveal that the GW corrections are particularly important in regions of the band structure where d and p states hybridize. For some systems, we show that GW corrections open a gap between occupied states, resulting in a band structure that closely resembles that of an intrinsic transparent conductor, thereby opening an additional line of prospective applications for the MXenes family. Nevertheless, GW and Bethe-Salpeter corrections have a minimal influence on the absorption spectra, in contrast to what is typically observed in semiconductor layers. Our present results suggest that calculations within the independent particle approximation (IPA) calculations are sufficiently accurate for assessing the optical characteristics of bulk-layered MXene materials. Finally, our calculated dielectric properties and absorption spectra, in agreement with existing experimental data, confirm the potential of MXenes as effective infrared emitters.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=brocade2&SrcAuth=WosAPI&KeyUT=WOS:001275 Publication Date 2024-07-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2475-9953 ISBN Additional Links UA library record; WoS full record
Impact Factor 3.4 Times cited Open Access
Notes Approved Most recent IF: 3.4; 2024 IF: NA
Call Number (down) UA @ admin @ c:irua:207597 Serial 9309
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Author Tian, X.; Xie, X.; Li, J.; Kong, X.; Gong, W.-J.; Peeters, F.M.; Li, L.
Title Multiferroic ScLaX₂ (X = P, As, and Sb) monolayers : bidirectional negative Poisson's ratio effects and phase transformations driven by rare-earth (main-group) elements Type A1 Journal article
Year 2024 Publication Physical review materials Abbreviated Journal
Volume 8 Issue 8 Pages 084407-84411
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract The combination of auxetic property, ferroelasticity, and ferroelectricity in two-dimensional materials offers new avenues for next-generation multifunctional devices. However, two-dimensional materials that simultaneously exhibit those properties are rarely reported. Here, we present a class of two-dimensional Janus-like structures ScLaX2 X 2 (X X = P, As, and Sb) with a rectangular lattice based on first-principles calculations. We predict that those ScLaX2 X 2 monolayers are stable semiconductors with both intrinsic in-plane and out-of-plane auxetic properties, showing a bidirectional negative Poisson's ratio effect. The value of the out-of-plane negative Poisson's ratio effect can reach – 2.28 /- 3.06 /- 3.89. By applying uniaxial strain engineering, two transition paths can be found, including the VA main group element path and the rare-earth metal element path, corresponding to the ferroelastic and the multiferroic (ferroelastic and ferroelectric) phase transition, respectively. For the ScLaSb2 2 monolayer, the external force field can not only control the ferroelastic phase transition, but it can also lead to the reversal of the out-of-plane polarization, exhibiting potential multiferroicity. The coupling between the bidirectional negative Poisson's ratio effect and multiferroicity makes the ScLaX2 X 2 monolayers promising for future device applications.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=brocade2&SrcAuth=WosAPI&KeyUT=WOS:001293 Publication Date 2024-08-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2475-9953 ISBN Additional Links UA library record; WoS full record
Impact Factor 3.4 Times cited Open Access
Notes Approved Most recent IF: 3.4; 2024 IF: NA
Call Number (down) UA @ admin @ c:irua:207592 Serial 9306
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Author Zhang, Y.; Grunewald, L.; Cao, X.; Abdelbarey, D.; Zheng, X.; Rugeramigabo, E.P.; Verbeeck, J.; Zopf, M.; Ding, F.
Title Unveiling the 3D morphology of epitaxial GaAs/AlGaAs quantum dots Type A1 Journal article
Year 2024 Publication Nano letters Abbreviated Journal
Volume 24 Issue 33 Pages 10106-10113
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Strain-free GaAs/AlGaAs semiconductor quantum dots (QDs) grown by droplet etching and nanohole infilling (DENI) are highly promising candidates for the on-demand generation of indistinguishable and entangled photon sources. The spectroscopic fingerprint and quantum optical properties of QDs are significantly influenced by their morphology. The effects of nanohole geometry and infilled material on the exciton binding energies and fine structure splitting are well-understood. However, a comprehensive understanding of GaAs/AlGaAs QD morphology remains elusive. To address this, we employ high-resolution scanning transmission electron microscopy (STEM) and reverse engineering through selective chemical etching and atomic force microscopy (AFM). Cross-sectional STEM of uncapped QDs reveals an inverted conical nanohole with Al-rich sidewalls and defect-free interfaces. Subsequent selective chemical etching and AFM measurements further reveal asymmetries in element distribution. This study enhances the understanding of DENI QD morphology and provides a fundamental three-dimensional structural model for simulating and optimizing their optoelectronic properties.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=brocade2&SrcAuth=WosAPI&KeyUT=WOS:001280 Publication Date 2024-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1530-6984 ISBN Additional Links UA library record; WoS full record
Impact Factor 10.8 Times cited Open Access
Notes Approved Most recent IF: 10.8; 2024 IF: 12.712
Call Number (down) UA @ admin @ c:irua:207525 Serial 9326
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Author Khalil, I.; Rigamonti, M.G.; Janssens, K.; Bugaev, A.; Arenas Esteban, D.; Robijns, S.; Donckels, T.; Beydokhti, M.T.; Bals, S.; De Vos, D.; Dusselier, M.
Title Atomically dispersed ruthenium hydride on beta zeolite as catalysts for the isomerization of muconates Type A1 Journal article
Year 2024 Publication Nature Catalysis Abbreviated Journal
Volume 7 Issue Pages 921-933
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Searching for sustainable polymers requires access to biomass-based monomers. In that sense, glucose-derived cis,cis-muconic acid stands as a high-potential intermediate. However, to unlock its potential, an isomerization to the value-added trans,trans-isomer, trans,trans-muconic acid, is required. Here we develop atomically dispersed low-loaded Ru on beta zeolite catalysts that produce trans,trans-muconate in ethanol with total conversion (to equilibrium) and a selectivity of >95%. We reach very high turnovers per Ru and productivity rates of 427 mM h(-1) (similar to 85 g l(-1) h(-1)), surpassing the bio-based cis,cis-muconic acid production rates by an order of magnitude. By coupling isomerization to Diels-Alder cycloaddition, terephthalate intermediates are produced in around 90% yields, circumventing the isomer equilibrium. Isomerization is promoted by Ru hydride species where the hydrides are generated from the alcohol solvent, as evidenced by Fourier transform infrared spectroscopy. Beyond isomerization, the Ru-zeolite and its hydride-forming capacity could be of use as a heterogeneous catalyst for other hydride chemistries, demonstrated by a successful hydride transfer hydrogenation.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=brocade2&SrcAuth=WosAPI&KeyUT=WOS:001294 Publication Date 2024-08-19
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2520-1158 ISBN Additional Links UA library record; WoS full record
Impact Factor 37.8 Times cited Open Access
Notes Approved Most recent IF: 37.8; 2024 IF: NA
Call Number (down) UA @ admin @ c:irua:207521 Serial 9277
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Author Bacaksiz, C.; Fyta, M.
Title Phthalocyanine adsorbed on monolayer CrI₃ : tailoring their magnetic properties Type A1 Journal article
Year 2024 Publication ACS Omega Abbreviated Journal
Volume 9 Issue 32 Pages 34589-34596
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Metallo-phthalocyanines molecules, especially ironphthalocyanines (Fe-Pc), are often examined due to their rich chemical, magnetic, and optoelectronic features. Due to these, Fe-Pc molecules are promising for applications in gas sensors, field-effect transistors, organic LEDs, and data storage. Motivated by this potential, this study investigates Fe-Pc molecules adsorbed on a magnetic monolayer, CrI3. Using quantum-mechanical simulations, the aim of this work was to find pathways to selectively tune and engineer the magnetic and electronic properties of the molecules when they form hybrid complexes. The results quantitatively underline how adsorption alters the magnetic properties of the Fe-Pc molecules. Interestingly, the analysis points to changes in the molecular magnetic anisotropy when comparing the magnetic moment of the isolated molecule to that of the molecule/monolayer complex formed after adsorption. The presence of iodine vacancies was shown to enhance the magnetic interactions between the iron of the Fe-Pc molecule and the chromium of the monolayer. Our findings suggest ways to control oxygen capture-release properties through material choice and defect creation. Insights into the stability and charge density depletion on the molecule provide critical information for selective tuning of the magnetic properties and engineering of the functionalities of these molecule/material complexes.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=brocade2&SrcAuth=WosAPI&KeyUT=WOS:001280 Publication Date 2024-07-29
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2470-1343 ISBN Additional Links UA library record; WoS full record
Impact Factor 4.1 Times cited Open Access
Notes Approved Most recent IF: 4.1; 2024 IF: NA
Call Number (down) UA @ admin @ c:irua:207512 Serial 9310
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Author Schram, J.; Parrilla, M.; Sleegers, N.; Slosse, A.; Van Durme, F.; van Nuijs, A.L.N.; De Wael, K.
Title Electrochemical classification of benzodiazepines : a comprehensive approach combining insights from voltammetry and liquid chromatography – mass spectrometry Type A1 Journal article
Year 2024 Publication Talanta : the international journal of pure and applied analytical chemistry Abbreviated Journal
Volume 279 Issue Pages 126623-10
Keywords A1 Journal article; Toxicological Centre; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab); Antwerp engineering, PhotoElectroChemistry & Sensing (A-PECS)
Abstract The growing non-medical use of benzodiazepines (BZs) has led to the emergence of counterfeit BZ pills and new psycho-active substances (NPS) in the BZ class on the illicit market. Comprehensive analytical methods for BZ identification are required to allow law enforcement, first aid responders and drug-checking services to analyze a variety of sample types and contents to make timely decisions on the spot. In this work, the electrochemical behavior of diazepam (DZ), clonazepam (CZ) and alprazolam (AP) is studied on graphite screen-printed electrodes, both with and without dissolved oxygen in the solution, to link their redox signals to their chemical structure. After elucidation of their reduction mechanisms using liquid chromatography coupled to highresolution mass spectrometry, three structural classes (Class 1, Class 2 and Class 3) were defined, each with different redox centers and electrochemical behavior. Subsequently, 22 confiscated pills containing 14 different BZs were correctly assigned to these three structural classes, with the deoxygenated conditions displaying the highest class selectivity. Finally, the three classes were successfully detected after being spiked into five alcoholic beverages in the context of drug-facilitated sexual assault. For analysis in red wine, which complicated the analysis by interfering with Class 1, a dual test strategy in pH 2 and pH 7 was proposed for accurate detection. Its rapid measurements, broad scope and lack of interference from diluents or colors makes this method a promising approach for aiding various services in combating problematic BZ use.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=brocade2&SrcAuth=WosAPI&KeyUT=WOS:001285 Publication Date 2024-07-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0039-9140; 1873-3573 ISBN Additional Links UA library record; WoS full record
Impact Factor 6.1 Times cited Open Access
Notes Approved Most recent IF: 6.1; 2024 IF: 4.162
Call Number (down) UA @ admin @ c:irua:207508 Serial 9285
Permanent link to this record
 

 
Author Steijlen, A.; Docter, M.; Bastemeijer, J.; Topyla, M.; Moraczewska, M.; Hoekstra, T.; Parrilla, M.; De Wael, K.
Title A practical guide to build a Raspberry Pi Pico based potentiostat for educational electrochemistry and electronic instrumentation Type A1 Journal article
Year 2024 Publication Journal of chemical education Abbreviated Journal
Volume Issue Pages
Keywords A1 Journal article; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab); Antwerp engineering, PhotoElectroChemistry & Sensing (A-PECS)
Abstract This manuscript presents the first practical guide to build a Raspberry Pi Pico based potentiostat for electrical and electrochemical instrumentation education. The circuit enables us to perform different types of voltammetry such as cyclic and square wave voltammetry. Voltammograms of paracetamol tablets in a neutral buffer solution were successfully recorded and compared to lab equipment. Thereafter, the effect of different scan rates and different concentrations was studied as a proof of concept. Furthermore, the experiments were expanded with measurements of other pharmaceutical tablets such as vitamin C. Over 80 nanobiology bachelor students successfully built their own potentiostat in an electronic instrumentation course. They validated their systems successfully with electrochemical experiments using paracetamol as a conventional pharmaceutical that can be performed in a classroom. The students acquired a valuable understanding of the electronic building blocks and system architecture within electrochemical instrumentation, equipping them with the requisite knowledge to effectively optimize instrumentation parameters in their future research work.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=brocade2&SrcAuth=WosAPI&KeyUT=WOS:001291 Publication Date 2024-08-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-9584; 1938-1328 ISBN Additional Links UA library record; WoS full record
Impact Factor 3 Times cited Open Access
Notes Approved Most recent IF: 3; 2024 IF: 1.419
Call Number (down) UA @ admin @ c:irua:207478 Serial 9276
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Author Barich, H.; Voet, O.; Sleegers, N.; Schram, J.; Montiel, F.N.; Beltran, V.; Nuyts, G.; De Wael, K.
Title Selecting optimal carbon inks for fabricating high-performance screen-printed electrodes for diverse electroanalytical applications Type A1 Journal article
Year 2024 Publication Journal of electroanalytical chemistry : an international journal devoted to all aspects of electrode kynetics, interfacial structure, properties of electrolytes, colloid and biological electrochemistry. Abbreviated Journal
Volume 971 Issue Pages 118585-11
Keywords A1 Journal article; Engineering sciences. Technology; Antwerp Electrochemical and Analytical Sciences Lab (A-Sense Lab); Antwerp engineering, PhotoElectroChemistry & Sensing (A-PECS)
Abstract Carbon-based screen-printed electrodes (SPEs) are extensively employed in electrochemistry due to their reproducibility, low-cost production, disposability and versatility. It is commonly accepted that batch to batch variations may occur due to variations in the ink formulation or the use of a different ink to print the electrodes. In this paper, three different commercial carbon-based inks (DuPont, Loctite and SunChemical) were used to manufacture SPEs, referred to respectively as Dup-SPE, Loc-SPE and Sun-SPE, using a semi-automated screen-printing technology. This study focuses on evaluating the quality, characteristics and electrochemical performance of the fabricated SPEs. Furthermore, the study aimed to investigate potential correlations between the ink composition and the nature of different target molecules, as well as their electroanalytical responses. Specifically, phenolic compounds and cocaine cutting agents are tested in alkaline conditions, while benzodiazepines and cephalosporine antibiotics are investigated in acidic media using square wave voltammetry (SWV). This aims to extract insights for the proper selection of inks and SPEs in both conditions. Additionally, a scan rate study of cephalosporine antibiotics using linear sweep voltammetry (LSV) is performed confirming the ion-exchange polymer layer on the electrode surface of Loc-SPE, which impact surface and electrochemical properties, leading to drawbacks in alkaline SWV sensing, but strategic benefits in reductive sensing resulting in an enhanced selective detection of specific targets. The insights on ink-specific influences on the surface and electrochemical properties of the SPEs obtained, may be useful for facilitating the electrode selection in diverse electrochemical applications, emphasizing the critical role of ink composition in achieving desired sensing capabilities.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2024-08-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1572-6657; 1873-2569 ISBN Additional Links UA library record
Impact Factor 4.5 Times cited Open Access
Notes Approved Most recent IF: 4.5; 2024 IF: 3.012
Call Number (down) UA @ admin @ c:irua:207447 Serial 9314
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Author Abadeen, A.Z.U.; Omranian, S.R.; Abdellati, Y.; Ag, K.R.; Verbruggen, S.; Vuye, C.
Title Investigating the potential effects of limestone and bitumen substrates on photocatalytic NOx degradation Type P1 Proceeding
Year 2024 Publication Abbreviated Journal
Volume 1 Issue Pages 3-12 T2 - Proceedings of the 10th International Co
Keywords P1 Proceeding; Engineering sciences. Technology; Sustainable Pavements and Asphalt Research (SuPAR); Antwerp engineering, PhotoElectroChemistry & Sensing (A-PECS)
Abstract NOx emissions commonly emitted by vehicles, pose environmental and health challenges worldwide. Photocatalytic asphalt pavements, used in urban settings, are in close contact with these emissions. In this study, the contribution and role of asphalt mix components—stone and bitumen—were analyzed in the degradation process. The effectiveness of TiO2 coatings on limestone-bitumen composites of varying ratios (100%, 75%, 50%, 25%, and 0%) was assessed using X-ray diffraction analysis (XRD), Confocal Laser Scanning Microscopy (CLSM), Fourier-transform infrared spectroscopy (FTIR), and the modified ISO 22197-1:2016 standard for NO removal. XRD verified the presence of calcite in limestone. CLSM revealed surface modifications and coating morphology, FTIR verified successful TiO2 PF2 coating deposition and NOx degradation quantified the NOx degradation (%), NO degradation (%) and NO2 formation (%) during photocatalytic activity. It was evident that samples with a higher ratio of stone-to-bitumen exhibited an elevated NOx degradation, reaching up to 29.11% for NOx, 43.79% for NO, and 13.96% for NO2 formation. Conversely, samples with a lower stone-to-bitumen ratio recorded values as low as 8.93% for NOx degradation (%), 10.30% for NO degradation (%), and 0.95% for NO2 formation (%). These outcomes firmly establish the inhibitory effect of the bitumen substrate on NOx and NO degradation but a positive effect on NO2 formation.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2024-07-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 978-3-031-63587-8 ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number (down) UA @ admin @ c:irua:207349 Serial 9299
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Author Ermiş, T.; Şen, A.O.; Gielis, J.
Title A new approach to circular inversion in l₁-normed spaces Type A1 Journal article
Year 2024 Publication Symmetry Abbreviated Journal
Volume 16 Issue 7 Pages 874-879
Keywords A1 Journal article; Engineering sciences. Technology; Antwerp engineering, PhotoElectroChemistry & Sensing (A-PECS)
Abstract While there are well-known synthetic methods in the literature for finding the image of a point under circular inversion in l2-normed geometry (Euclidean geometry), there is no similar synthetic method in Minkowski geometry, also known as the geometry of finite-dimensional Banach spaces. In this study, we have succeeded in creating a synthetic construction of the circular inversion in l1-normed spaces, which is one of the most fundamental examples of Minkowski geometry. Moreover, this synthetic construction has been given using the Euclidean circle, independently of the l1-norm.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001278345600001 Publication Date 2024-07-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2073-8994 ISBN Additional Links UA library record; WoS full record
Impact Factor 2.7 Times cited Open Access
Notes Approved Most recent IF: 2.7; 2024 IF: 1.457
Call Number (down) UA @ admin @ c:irua:207314 Serial 9307
Permanent link to this record
 

 
Author Lavor, I.R.; Tao, Z.H.; Dong, H.M.; Chaves, A.; Peeters, F.M.; Milošević, M.V.
Title Ultrasensitive acoustic graphene plasmons in a graphene-transition metal dichalcogenide heterostructure : strong plasmon-phonon coupling and wavelength sensitivity enhanced by a metal screen Type A1 Journal article
Year 2024 Publication Carbon Abbreviated Journal
Volume 228 Issue Pages 119401-119409
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract Acoustic plasmons in graphene exhibit strong confinement induced by a proximate metal surface and hybridize with phonons of transition metal dichalcogenides (TMDs) when these materials are combined in a van der Waals heterostructure, thus forming screened graphene plasmon-phonon polaritons (SGPPPs), a type of acoustic mode. While SGPPPs are shown to be very sensitive to the dielectric properties of the environment, enhancing the SGPPPs coupling strength in realistic heterostructures is still challenging. Here we employ the quantum electrostatic heterostructure model, which builds upon the density functional theory calculations for monolayers, to show that the use of a metal as a substrate for graphene-TMD heterostructures (i) vigorously enhances the coupling strength between acoustic plasmons and the TMD phonons, and (ii) markedly improves the sensitivity of the plasmon wavelength on the structural details of the host platform in real space, thus allowing one to use the effect of environmental screening on acoustic plasmons to probe the structure and composition of a van der Waals heterostructure down to the monolayer resolution.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=brocade2&SrcAuth=WosAPI&KeyUT=WOS:001267 Publication Date 2024-07-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0008-6223 ISBN Additional Links UA library record; WoS full record; WoS full record
Impact Factor 10.9 Times cited Open Access
Notes Approved Most recent IF: 10.9; 2024 IF: 6.337
Call Number (down) UA @ admin @ c:irua:207077 Serial 9325
Permanent link to this record
 

 
Author Vermeulen, B.B.; Sorée, B.; Couet, S.; Temst, K.; Van Nguyen, D.
Title Progress in spin logic devices based on domain-wall motion Type A1 Journal article
Year 2024 Publication Micromachines Abbreviated Journal
Volume 15 Issue 6 Pages 696-20
Keywords A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT)
Abstract Spintronics, utilizing both the charge and spin of electrons, benefits from the nonvolatility, low switching energy, and collective behavior of magnetization. These properties allow the development of magnetoresistive random access memories, with magnetic tunnel junctions (MTJs) playing a central role. Various spin logic concepts are also extensively explored. Among these, spin logic devices based on the motion of magnetic domain walls (DWs) enable the implementation of compact and energy-efficient logic circuits. In these devices, DW motion within a magnetic track enables spin information processing, while MTJs at the input and output serve as electrical writing and reading elements. DW logic holds promise for simplifying logic circuit complexity by performing multiple functions within a single device. Nevertheless, the demonstration of DW logic circuits with electrical writing and reading at the nanoscale is still needed to unveil their practical application potential. In this review, we discuss material advancements for high-speed DW motion, progress in DW logic devices, groundbreaking demonstrations of current-driven DW logic, and its potential for practical applications. Additionally, we discuss alternative approaches for current-free information propagation, along with challenges and prospects for the development of DW logic.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=brocade2&SrcAuth=WosAPI&KeyUT=WOS:001256 Publication Date 2024-05-27
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2072-666x ISBN Additional Links UA library record; WoS full record; WoS full record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number (down) UA @ admin @ c:irua:207054 Serial 9312
Permanent link to this record
 

 
Author Yuan, M.-M.; Wang, L.-D.; Zhang, J.; Ran, M.-J.; Wang, K.; Hu, Z.-Y.; Van Tendeloo, G.; Li, Y.; Su, B.-L.
Title Cut-off voltage influencing the voltage decay of single crystal lithium-rich manganese-based cathode materials in lithium-ion batteries Type A1 Journal article
Year 2024 Publication Journal of colloid and interface science Abbreviated Journal
Volume 674 Issue Pages 238-248
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The voltage decay of Li -rich layered oxide cathode materials results in the deterioration of cycling performance and continuous energy loss, which seriously hinders their application in the high-energy – density lithium -ion battery (LIB) market. However, the origin of the voltage decay mechanism remains controversial due to the complex influences of transition metal (TM) migration, oxygen release, indistinguishable surface/bulk reactions and the easy intra/inter-crystalline cracking during cycling. We investigated the direct cause of voltage decay in micrometer -scale single -crystal Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 (SC-LNCM) cathode materials by regulating the cut-off voltage. The redox of TM and O 2- ions can be precisely controlled by setting different voltage windows, while the cracking can be restrained, and surface/bulk structural evaluation can be monitored because of the large single crystal size. The results show that the voltage decay of SC-LNCM is related to the combined effect of cation rearrangement and oxygen release. Maintaining the discharge cutoff voltage at 3 V or the charging cutoff voltage at 4.5 V effectively mitigates the voltage decay, which provides a solution for suppressing the voltage decay of Lirich and Mn-based layered oxide cathode materials. Our work provides significant insights into the origin of the voltage decay mechanism and an easily achievable strategy to restrain the voltage decay for Li -rich and Mn-based cathode materials.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=brocade2&SrcAuth=WosAPI&KeyUT=WOS:001261 Publication Date 2024-06-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0021-9797; 1095-7103 ISBN Additional Links UA library record; WoS full record; WoS full record
Impact Factor 9.9 Times cited Open Access
Notes Approved Most recent IF: 9.9; 2024 IF: 4.233
Call Number (down) UA @ admin @ c:irua:207026 Serial 9281
Permanent link to this record
 

 
Author Liang, Z.; Batuk, M.; Orlandi, F.; Manuel, P.; Hadermann, J.; Hayward, M.A.
Title Competition between anion-deficient oxide and oxyhydride phases during the topochemical reduction of LaSrCoRuO₆ Type A1 Journal article
Year 2024 Publication Inorganic chemistry Abbreviated Journal
Volume 63 Issue 28 Pages 12910-12919
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Binary metal hydrides can act as low-temperature reducing agents for complex oxides in the solid state, facilitating the synthesis of anion-deficient oxide or oxyhydride phases. The reaction of LaSrCoRuO6, with CaH2 in a sealed tube yields the face-centered cubic phase LaSrCoRuO3.2H1.9. The reaction with LiH under similar conditions converts LaSrCoRuO6 to a mixture of tetragonal LaSrCoRuO4.8H1.2 and cubic LaSrCoRuO3.3H2.13. The formation of the LaSrCoRuOxHy oxyhydride phases proceeds directly from the parent oxide, with no evidence for anion-deficient LaSrCoRuO6-x intermediates, in contrast with many other topochemically synthesized transition-metal oxyhydrides. However, the reaction between LaSrCoRuO6 and LiH under flowing argon yields a mixture of LaSrCoRuO5 and the infinite layer phase LaSrCoRuO4. The change to all-oxide products when reactions are performed under flowing argon is attributed to the lower hydrogen partial pressure under these conditions. The implications for the reaction mechanism of these topochemical transformations is discussed along with the role of the hydrogen partial pressure in oxyhydride synthesis. Magnetization measurements indicate the LaSrCoRuOxHy phases exhibit local moments on Co and Ru centers, which are coupled antiferromagnetically. In contrast, LaSrCoRuO4 exhibits ferromagnetic behavior with a Curie temperature above 350 K, which can be rationalized on the basis of superexchange coupling between the Co1+ and Ru2+ centers.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=brocade2&SrcAuth=WosAPI&KeyUT=WOS:001259 Publication Date 2024-06-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0020-1669 ISBN Additional Links UA library record; WoS full record; WoS full record
Impact Factor 4.6 Times cited Open Access
Notes Approved Most recent IF: 4.6; 2024 IF: 4.857
Call Number (down) UA @ admin @ c:irua:207018 Serial 9280
Permanent link to this record
 

 
Author Kadu, A.; Lucka, F.; Batenburg, K.J.
Title Single-shot tomography of discrete dynamic objects Type A1 Journal article
Year 2024 Publication IEEE transactions on computational imaging Abbreviated Journal
Volume 10 Issue Pages 941-952
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract This paper presents a novel method for the reconstruction of high-resolution temporal images in dynamic tomographic imaging, particularly for discrete objects with smooth boundaries that vary over time. Addressing the challenge of limited measurements per time point, we propose a technique that incorporates spatial and temporal information of the dynamic objects. Our method uses the explicit assumption of homogeneous attenuation values of discrete objects. We achieve this computationally through the application of the level-set method for image segmentation and the representation of motion via a sinusoidal basis. The result is a computationally efficient and easily optimizable variational framework that enables the reconstruction of high-quality 2D or 3D image sequences with a single projection per frame. Compared to variational regularization-based methods using similar image models, our approach demonstrates superior performance on both synthetic and pseudo-dynamic real X-ray tomography datasets. The implications of this research extend to improved visualization and analysis of dynamic processes in tomographic imaging, finding potential applications in diverse scientific and industrial domains. The supporting data and code are provided.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=brocade2&SrcAuth=WosAPI&KeyUT=WOS:001256 Publication Date 2024-06-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2573-0436; 2333-9403 ISBN Additional Links UA library record; WoS full record; WoS full record
Impact Factor 5.4 Times cited Open Access
Notes Approved Most recent IF: 5.4; 2024 IF: NA
Call Number (down) UA @ admin @ c:irua:207017 Serial 9315
Permanent link to this record
 

 
Author Paramasivam, S.K.; Gangadharan, S.P.; Milošević, M.V.; Perali, A.
Title High-Tc Berezinskii-Kosterlitz-Thouless transition in two-dimensional superconducting systems with coupled deep and quasiflat electronic bands with Van Hove singularities Type A1 Journal article
Year 2024 Publication Physical review B Abbreviated Journal
Volume 110 Issue 2 Pages 024507-24511
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract In the pursuit of higher critical temperature of superconductivity, quasiflat electronic bands and Van Hove singularities in two dimensions (2D) have emerged as a potential approach to enhance Cooper pairing on the basis of mean-field expectations. However, these special electronic features suppress the superfluid stiffness and, hence, the Berezinskii-Kosterlitz-Thouless (BKT) transition in 2D superconducting systems, leading to the emergence of a significant pseudogap regime due to superconducting fluctuations. In the strong-coupling regime, one finds that superfluid stiffness is inversely proportional to the superconducting gap, which is the predominant factor contributing to the strong suppression of superfluid stiffness. Here we reveal that the aforementioned limitation is avoided in a 2D superconducting electronic system with a quasiflat electronic band with a strong pairing strength coupled to a deep band with weak electronic pairing strength. Owing to the multiband effects, we demonstrate a screening-like mechanism that circumvents the suppression of the superfluid stiffness. We report the optimal conditions for achieving a large enhancement of the BKT transition temperature and a substantial shrinking of the pseudogap regime by tuning the intraband couplings and the pair-exchange coupling between the two band-condensates.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=brocade2&SrcAuth=WosAPI&KeyUT=WOS:001267 Publication Date 2024-07-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record; WoS full record
Impact Factor 3.7 Times cited Open Access
Notes Approved Most recent IF: 3.7; 2024 IF: 3.836
Call Number (down) UA @ admin @ c:irua:207014 Serial 9295
Permanent link to this record
 

 
Author Šoškić, B.N.; Bekaert, J.; Sevik, C.; Šljivančanin, Ž.; Milošević, M.V.
Title First-principles exploration of superconductivity in intercalated bilayer borophene phases Type A1 Journal article
Year 2024 Publication Physical review materials Abbreviated Journal
Volume 8 Issue 6 Pages 064803-64811
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We explore the emergence of phonon-mediated superconductivity in bilayer borophenes by controlled intercalation with elements from the groups of alkali, alkaline-earth, and transition metals, using systematic first-principles and Eliashberg calculations. We show that the superconducting properties are primarily governed by the interplay between the out-of-plane (????????) boron states and the partially occupied in-plane (????+????????,????) bonding states at the Fermi level. Our Eliashberg calculations indicate that intercalation with alkaline-earth-metal elements leads to the highest superconducting critical temperatures (????????). Specifically, Be in ????4, Mg in ????3, and Ca in the kagome bilayer borophene demonstrate superior performance with ???????? reaching up to 58 K. Our study therefore reveals that intercalated bilayer borophene phases are not only more resilient to chemical deterioration, but also harbor enhanced ???????? values compared to their monolayer counterparts, underscoring their substantial potential for the development of boron-based two-dimensional superconductors.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=brocade2&SrcAuth=WosAPI&KeyUT=WOS:001254 Publication Date 2024-06-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2475-9953 ISBN Additional Links UA library record; WoS full record
Impact Factor 3.4 Times cited Open Access
Notes Approved Most recent IF: 3.4; 2024 IF: NA
Call Number (down) UA @ admin @ c:irua:206919 Serial 9290
Permanent link to this record
 

 
Author Gao, C.
Title Exploring electron ptychography for low dose imaging Type Doctoral thesis
Year 2024 Publication Abbreviated Journal
Volume Issue Pages xii, 146 p.
Keywords Doctoral thesis; Electron microscopy for materials research (EMAT)
Abstract Transmission electron microscopy is an important technique in the exploration of materials’ structures. This is especially true since the development of electron optical aberration correctors greatly facilitated atomic resolution imaging. We are currently experiencing an ongoing revolution in electron microscopy with the widespread adoption of direct electron detectors. Scientists have reported a lot of key scientific findings facilitated by direct electron detectors. One particular research domain is electron ptychography, which holds promise for unraveling the intricate structures of highly beam-sensitive materials like bio samples and achieving super-resolution without the limitation of aperture in the condenser lens system. Nevertheless, challenges persist both in experimental setups and algorithmic processes. Issues such as the comparatively sluggish scanning speed of cameras and contrast reversals of the reconstructed phase for relatively thick specimens, disrupting phase or weak phase approximations, remain noteworthy limitations. This thesis addresses these challenges by the event-driven Timepix3 detector, presenting a viable solution to the speed bottleneck. Moreover, innovative approaches for applying electron ptychography to relatively thick samples, employing a middle focusing strategy, are proposed. This research aims to push the boundaries of electron microscopy, offering solutions to existing limitations and advancing the field towards more efficient and accurate imaging techniques.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2024-07-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number (down) UA @ admin @ c:irua:206777 Serial 9289
Permanent link to this record
 

 
Author Ninakanti, R.
Title Synthesis and electron microscopy characterization of novel core-shell and self-assembled nanostructures for plasmon-enhanced photocatalysis Type Doctoral thesis
Year 2024 Publication Abbreviated Journal
Volume Issue Pages 163 p.
Keywords Doctoral thesis; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Antwerp engineering, PhotoElectroChemistry & Sensing (A-PECS)
Abstract The global challenge posed by increasing levels of greenhouse gases and the associated detrimental impacts of global warming necessitate a strategic shift from traditional fossil fuel-based energy systems to more sustainable, renewable, and circular energy and material solutions. Consequently, the potential of photoactive nanoparticles, particularly those that harness light-driven processes, has captured extensive scientific interest as a viable approach to mitigating energy and environmental challenges on a global scale. Although, the adoption of solar light based solutions in the chemical industry has been very less due to sluggish reaction rates and its cascading effects on its economics. The primary focus of this dissertation is the study of plasmonic metal nanoparticles and metal oxide nanoparticles, emphasizing their applications in light-driven energy conversion. The distinctive properties of plasmonic materials, especially surface plasmon resonance (SPR), are pivotal in these applications. SPR involves the oscillation of electron clouds at the surface of nanoparticles when resonating with incident electromagnetic radiation, significantly enhancing solar radiation absorption. This feature is crucial for addressing the limitations of semiconductor photocatalysts like TiO2, which typically exhibit restricted absorption of solar irradiation. The objective of this dissertation is to further optimize the plasmonic enhancement mechanisms by strategically tuning the interactions between plasmonic nanoparticles and TiO2. This is achieved through the development of core-shell nanostructures and the self-assembly of supraparticles, designed to enhance plasmonic photocatalytic systems. The dissertation begins by elucidating the basic concepts and ideations behind the construction of these nanostructures and their roles in enhancing plasmonic photocatalysis, focusing on mechanisms such as near-electric field enhancement, electron transfer, and enhanced photon absorption. To achieve these objectives, modified synthesis techniques were developed to fabricate novel Au@TiO2 core-shell structures with precisely controlled TiO2 shell thickness and self-assembled Au-TiO2 supraparticles with variable sizes. The thesis further delves into the structural characterization of these synthesized nanoparticles, introducing both basic and advanced electron microscopy techniques. For the specific applications of these structures, it was found that Au@TiO2 core-shell nanoparticles with an optimal 4nm TiO2 shell thickness show significant enhancement in the hydrogen evolution reaction. Additionally, the largest Au-TiO2 supraparticles demonstrate superior efficacy in hydrogen peroxide generation. This work not only deepens the scientific understanding of plasmonic materials but also contributes to the development of renewable energy materials.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2024-07-04
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number (down) UA @ admin @ c:irua:206768 Serial 9320
Permanent link to this record
 

 
Author Chinnabathini, V.C.
Title Gas phase bimetallic nanoclusters-modified TiO2 supports as efficient photo(electro)catalysts for self-cleaning surfaces and water splitting Type Doctoral thesis
Year 2024 Publication Abbreviated Journal
Volume Issue Pages xviii, 149 p.
Keywords Doctoral thesis; Antwerp engineering, PhotoElectroChemistry & Sensing (A-PECS)
Abstract In the context of global challenges such as climate change and environmental pollution, photocatalysis evolved as one of the promising strategies for sustainable energy conversion and pollutant degradation. In this thesis, photocatalysis using gas phase deposited bimetallic nanoclusters (BNCs) on TiO2 supports is studied in the context of self-cleaning surfaces and photoelectrochemical (PEC) water splitting applications. Thanks to their plasmonic properties, BNCs made of coinage metals can serve as efficient cocatalysts for the degradation of organic pollutants and surface contaminants under light irradiation. They also hold great promise for PEC water splitting, a promising pathway for renewable hydrogen production, which can be used in hydrogen fuel cells or for the environmentally friendly production of fuels in, for example, CO2 hydrogenation processes. The small size and high surface-to-volume ratio of plasmonic BNCs play pivotal roles in influencing the efficiency and selectivity of photocatalytic processes. BNCs have unique optical, physical, chemical, and structural properties distinctly different from their bulk and monometallic counterparts. These properties can be fine-tuned at the single particle level by their size, composition, and atomic arrangement, but also by interaction with other particles through the coverage and through interaction with the support. To design better photocatalysts it is crucial to carefully understand the BNCs’ characteristic properties, especially at the atomic level where synergies between different elements are sought. To achieve this objective, BNCs with well-defined sizes and compositions are deposited on TiO2 supports and we studied their structural properties and their influence on the photocatalytic activity. The general procedure followed in this thesis is the production and deposition of BNCs on TiO2 by the cluster beam deposition (CBD) technique, followed by structural and optical characterization to understand their tailored properties, and photocatalytic testing either for photodecomposition of organic molecules or PEC water splitting. In a first study, AuxAg1-x (x = 1, 0.9, 0.7, 0.5, 0.3, and 0) alloy BNCs with different compositions are synthesized in the gas phase and deposited from a molecular beam on TiO2 P25 supports. The photocatalytic self-cleaning activity of as-prepared samples is tested under UV and visible light towards stearic acid (SA) degradation. SA is a widely accepted model contaminant, which represents the group of organic fouling compounds that typically contaminates glass surfaces. A composition-dependent activity is observed with the Au0.3Ag0.7 nanocluster modified TiO2 exhibiting the highest photoactivity. Scanning transmission electron microscopy (STEM) measurements reveal that, for a mass loading corresponding to an equivalent of 4 atomic monolayers (MLs), the BNCs are uniformly distributed over the surface. The clusters have an average size of 3.5 ± 0.5 nm and are crystalline in nature. The atomic structure is characterized by X-ray absorption fine structure (XAFS) spectroscopy and their electronic structure by X-ray photoelectron spectroscopy (XPS). These measurements demonstrate a charge redistribution between the Ag and Au atoms when alloyed at the nanoscale. The effect of this charge redistribution is likely the stabilization of Ag against oxidation and directly affects the catalytic properties of the clusters. It is suggested that the highest photoactivity of 4 ML loaded Au0.3Ag0.7 under solar light results from a combination of four main possible contributing factors: (i) injection in TiO2 of excited carriers that are generated by the localized surface plasmon resonance (LSPR) effect of the BNCs in the visible light wavelength range which overlaps with the sun’s irradiance spectrum. (ii) a strong near-field enhancement that increases the photoabsorption by the TiO2 for photons that have enough energy to overcome the high bandgap, (iii) the optimized total metal loading of 4 ML leaves enough of the TiO2 surface accessible for light absorption, and finally (iv) an effective charge distribution between Au and Ag. This study demonstrates that CBD is an efficient approach for fabricating well-defined, tunable AuAg plasmon-based photocatalysts for self-cleaning applications, outperforming their monometallic counterparts as well as bimetallic alternatives obtained through colloidal methods. In a second study, titania nanotubes (TNTs) are modified with a series of AuxCu1-x (x = 1, 0.75, 0.5, 0.25, and 0) BNCs using the CBD technique. Based on the results of the first study, we opted again for a loading of 4 ML. TNTs are known for their high surface area, fast charge transfer, and corrosion resistance, while keeping the inherent strengths of traditional TiO2 materials. They prove to be promising photoanodes, enhancing photocurrent in PEC applications for water oxidation. In this work the TNTs are grown via anodic oxidation of a titanium metal foil. The crystalline anatase phase of the grown TNTs is confirmed by the X-ray diffraction technique (XRD), while transmission electron microscopy (TEM) provides information about the size and composition of the deposited BNCs. XAFS provides further structural information, while XPS measurements reveal charge redistribution between Au and Cu, which can aid in the enhancement of the PEC activity. Oxidation of as-prepared electrodes over the time results in structural changes with CuxO at the outer shell functioning as a protective layer, while the majority of the core is an alloy. The optical properties, studied through UV-Vis spectroscopy confirm the extended absorption range of the cluster-modified TNTs towards the visible region. The charge carrier recombination rate is derived from photoluminescence (PL) measurements. The as-prepared electrodes are tested photoelectrochemically for the generation of an anodic photocurrent using simulated sunlight. It is found that the AuxCu1-x (x = 1, 0.75, 0.5, 0.25 and 0) BNC modified TNTs show a remarkable enhancement in the anodic photocurrent relative to pristine TNTs, with Au0.25Cu0.75 exhibiting the highest photocurrent. This is due to the combination of many possible factors. Firstly, the charge redistribution between Au and Cu and increase stability of the Au0.25Cu0.75 electrode as observed in XAFS, indicates that the electronic effect in the cluster is also one of the governing factors for PEC activity. Secondly, formation of a surface CuOx layer, protects against further corrosion of the metallic AuCu BNCs cores. Third, reduced recombination of charge carriers is indicated by lower photoluminescent (PL) intensity compared to pristine TNTs and all other electrodes except pure gold, as observed in PL spectra. This implies that the generated charge carriers are efficiently separated by Au0.25Cu0.75 NCs acting as electron sinks and easily available for redox reactions. Fourth, the highest interfacial charge transfer efficiency is evidenced by the electrochemical impedance spectroscopy (EIS), leading to more efficacious charge migration and separation, facilitating the water oxidation surface reaction. A final beneficial factor is the uniform deposition of well-defined, size- and composition-controlled, ligand-free BNCs. Such BNCs provide more effective surface sites to the reaction medium, in contrast to electrodes synthesized by e.g. sol-gel methods, where (in)organic residues on metal surfaces may decrease the efficiency.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2024-07-04
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number (down) UA @ admin @ c:irua:206758 Serial 9293
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Author Li, Q.N.; Vasilopoulos, P.; Peeters, F.M.; Xu, W.; Xiao, Y.M.; Milošević, M.V.
Title Collective excitations in three-dimensional Dirac systems Type A1 Journal article
Year 2024 Publication Physical review B Abbreviated Journal
Volume 109 Issue 11 Pages 115123-115129
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We provide the plasmon spectrum and related properties of the three-dimensional (3D) Dirac semimetals Na 3 Bi and Cd 3 As 2 based on the random -phase approximation. The necessary one -electron eigenvalues and eigenfunctions are obtained from an effective k <middle dot> p Hamiltonian. Below the energy at which the velocity v z along the k z axis vanishes, the density of states differs drastically from that of a 3D electron gas (3DEG) or graphene. The dispersion relation is anisotropic for wave vectors parallel ( q ) and perpendicular ( q z ) to the ( x , y ) plane and is markedly different than that of graphene or a 3DEG. The same holds for the energy -loss function. Both depend sensitively on the position of the Fermi energy E F relative to the region of the Berry curvature of the bands. For E F below the energy at which v z vanishes, the range of the relevant wave vectors q and q z shrinks, for q z by about one order of magnitude.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001235353700005 Publication Date 2024-03-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2469-9969; 2469-9950 ISBN Additional Links UA library record; WoS full record
Impact Factor 3.7 Times cited Open Access
Notes Approved Most recent IF: 3.7; 2024 IF: 3.836
Call Number (down) UA @ admin @ c:irua:206669 Serial 9278
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Author Gonzalez-Garcia, A.; Bacaksiz, C.; Frauenheim, T.; Milošević, M.V.
Title Strong spin-lattice coupling and high-temperature magnetic ordering in monolayer chromium dichalcogenides Type A1 Journal article
Year 2024 Publication Physical review materials Abbreviated Journal
Volume 8 Issue 6 Pages 064001-64009
Keywords A1 Journal article; Condensed Matter Theory (CMT)
Abstract We detail the magnetic properties of monolayer CrX2 and its Janus counterparts CrXY (X, Y = S, Se, Te, with X not equal Y) using ab initio methods and Landau-Lifshitz-Gilbert magnetization dynamics, and uncover the pronouncedly strong interplay between their structure symmetry and the magnetic order. The relaxation of nonmagnetic chalcogen atoms, that carry large spin-orbit coupling, changes the energetically preferential magnetic order between in-plane antiferromagnetic and tilted ferromagnetic one. The considered Janus monolayers exhibit sizable Dzyaloshinskii-Moriya interaction, in some cases above 20% of the isotropic exchange, and critical temperature of the long-range magnetic order in the vicinity or even significantly above the room temperature.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001247462600001 Publication Date 2024-06-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2475-9953 ISBN Additional Links UA library record; WoS full record
Impact Factor 3.4 Times cited Open Access
Notes Approved Most recent IF: 3.4; 2024 IF: NA
Call Number (down) UA @ admin @ c:irua:206660 Serial 9317
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