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Author Cabana, L.; Ke, X.; Kepić, D.; Oro-Solé, J.; Tobías-Rossell, E.; Van Tendeloo, G.; Tobias, G.
Title The role of steam treatment on the structure, purity and length distribution of multi-walled carbon nanotubes Type A1 Journal article
Year 2015 Publication Carbon Abbreviated Journal Carbon
Volume 93 Issue 93 Pages 1059-1067
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Purification and shortening of carbon nanotubes have attracted a great deal of attention to increase the biocompatibility and performance of the material in several applications. Steam treatment has been employed to afford both purification and shortening of multi-walled carbon nanotubes (MWCNTs). Steam removes the amorphous carbon and the graphitic particles that sheath catalytic nanoparticles, facilitating their removal by a subsequent acidic wash. The amount of metal impurities can be reduced in this manner below 0.01 wt.%. The length distribution of MWCNTs after different steam treatment times (from 1 h to 15 h) was assessed by box plot analysis of the electron microscopy data. Samples with a median length of 0.57 μm have been prepared with the reported methodology while preserving the integrity of the tubular wall structure.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000360292100108 Publication Date 2015-06-23
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 citing articles
Impact Factor (up) 6.337 Times cited 17 Open Access
Notes 312483 Esteem2; 290023 Raddel; esteem2_ta Approved Most recent IF: 6.337; 2015 IF: 6.196
Call Number c:irua:127691 c:irua:127691 Serial 2921
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Author Li, Y.; Zhang, X.B.; Tao, X.Y.; Xu, J.M.; Chen, F.; Shen, L.H.; Yang, X.F.; Liu, F.; Van Tendeloo, G.; Geise, H.J.
Title Single phase MgMoO4 as catalyst for the synthesis of bundled multi-wall carbon nanotubes by CVD Type L1 Letter to the editor
Year 2005 Publication Carbon Abbreviated Journal Carbon
Volume 43 Issue 6 Pages 1325-1328
Keywords L1 Letter to the editor; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000228676400026 Publication Date 2005-03-11
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 citing articles
Impact Factor (up) 6.337 Times cited 23 Open Access
Notes Iap V-1 Approved Most recent IF: 6.337; 2005 IF: 3.419
Call Number UA @ lucian @ c:irua:59055 Serial 3026
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Author Tao, X.Y.; Zhang, X.B.; Zhang, L.; Cheng, J.P.; Liu, F.; Luo, J.H.; Luo, Z.Q.; Geise, H.J.
Title Synthesis of multi-branched porous carbon nanofibers and their application in electrochemical double-layer capacitors Type A1 Journal article
Year 2006 Publication Carbon Abbreviated Journal Carbon
Volume 44 Issue 8 Pages 1425-1428
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000237765000008 Publication Date 2006-01-11
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 citing articles
Impact Factor (up) 6.337 Times cited 77 Open Access
Notes Approved Most recent IF: 6.337; 2006 IF: 3.884
Call Number UA @ lucian @ c:irua:59477 Serial 3458
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Author Titantah, J.T.; Lamoen, D.
Title sp3/sp2 characterization of carbon materials from first-principles calculations: X-ray photoelectron versus high energy electron energy-loss spectroscopy techniques Type A1 Journal article
Year 2005 Publication Carbon Abbreviated Journal Carbon
Volume 43 Issue 6 Pages 1311-1316
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000228676400022 Publication Date 2005-02-18
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 citing articles
Impact Factor (up) 6.337 Times cited 70 Open Access
Notes Approved Most recent IF: 6.337; 2005 IF: 3.419
Call Number UA @ lucian @ c:irua:51762 Serial 3558
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Author He, Z.; Lee, C.S.; Maurice, J.-L.; Pribat, D.; Haghi-Ashtiani, P.; Cojocaru, C.S.
Title Vertically oriented nickel nanorod/carbon nanofiber core/shell structures synthesized by plasma-enhanced chemical vapor deposition Type A1 Journal article
Year 2011 Publication Carbon Abbreviated Journal Carbon
Volume 49 Issue 14 Pages 4710-4718
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Plasma-enhanced chemical vapor deposition, without a nickel-containing gaseous precursor, was used to synthesize continuous nickel (Ni) nanorods inside the hollow cavity of carbon nanofibers (CNFs), thus forming vertically aligned Ni/CNF core/shell structures. Scanning and transmission electron microscopic images indicate that the elongated Ni nanorods originate from the catalyst particles at the tips of the CNFs and that their formation is due to the effect of extrusion induced by the compressive force of the graphene layers during growth. Different from previous work, each vertically-aligned core/shell structure reported is totally isolated from its neighbors. Continuous Ni nanorods are found to separate into smaller ones with increasing growth time, which was ascribed to (i) the limited amount of Ni available in the tip of the CNF, (ii) the polycrystalline nature of the Ni nanorods and (iii) the combined effects of the compressive stresses on the side of the Ni nanorods and of the tensile stress along their axis.
Address
Corporate Author Thesis
Publisher Place of Publication Oxford Editor
Language Wos 000295308300010 Publication Date 2011-06-30
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 citing articles
Impact Factor (up) 6.337 Times cited 16 Open Access
Notes Approved Most recent IF: 6.337; 2011 IF: 5.378
Call Number UA @ lucian @ c:irua:92782 Serial 3841
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Author Kleshch, V.I.; Porshyn, V.; Orekhov, A.S.; Orekhov, A.S.; Lützenkirchen-Hecht, D.; Obraztsov, A.N.
Title Carbon single-electron point source controlled by Coulomb blockade Type A1 Journal article
Year 2021 Publication Carbon Abbreviated Journal Carbon
Volume 171 Issue Pages 154-160
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The Coulomb blockade effect is commonly used in solid state electronics for the control of electron flow

at the single-particle level. Potentially, it allows the creation of single-electron point sources demanded

for prospective electron microscopy instruments and other vacuum electronics devices. Here we realize

this potential via creation of a stable point electron source composed of a carbon nanowire electrically

coupled to a diamond nanotip by a tunnel junction. Using energy spectroscopy analysis, we characterize

the electrons liberated from the nanometer scale carbon heterostructures in time and energy domains.

Our experimental results demonstrate perfect agreement with theory prediction of Coulomb oscillations

of the Fermi level in the nanowire and allow to determine the mechanisms of their suppression.

Persistence of the oscillations at room temperature, high intensity field emission with currents up to

1 mA, and other characteristics of our emitters are very promising for practical realization of coherent

single-electron guns.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000598371500018 Publication Date 2020-09-06
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 citing articles
Impact Factor (up) 6.337 Times cited Open Access OpenAccess
Notes The work was supported by Russian Science Foundation (Project No. 19-72-10067). Approved Most recent IF: 6.337
Call Number EMAT @ emat @c:irua:175013 Serial 6670
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Author Pandey, T.; Covaci, L.; Peeters, F.M.
Title Tuning flexoelectricty and electronic properties of zig-zag graphene nanoribbons by functionalization Type A1 Journal article
Year 2021 Publication Carbon Abbreviated Journal Carbon
Volume 171 Issue Pages 551-559
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract The flexoelectric and electronic properties of zig-zag graphene nanoribbons are explored under mechanical bending using state of the art first principles calculations. A linear dependence of the bending induced out of plane polarization on the applied strain gradient is found. The inferior flexoelectric properties of graphene nanoribbons can be improved by more than two orders of magnitude by hydrogen and fluorine functionalization (CH and CF nanoribbons). A large out of plane flexoelectric effect is predicted for CF nanoribbons. The origin of this enhancement lies in the electro-negativity difference between carbon and fluorine atoms, which breaks the out of plane charge symmetry even for a small strain gradient. The flexoelectric effect can be further improved by co-functionalization with hydrogen and fluorine (CHF Janus-type nanoribbon), where a spontaneous out of plane dipole moment is formed even for flat nanoribbons. We also find that bending can control the charge localization of valence band maxima and therefore enables the tuning of the hole effective masses and band gaps. These results present an important advance towards the understanding of flexoelectric and electronic properties of hydrogen and fluorine functionalized graphene nanoribbons, which can have important implications for flexible electronic applications. (C) 2020 Elsevier Ltd. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000598371500058 Publication Date 2020-09-17
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 citing articles
Impact Factor (up) 6.337 Times cited 11 Open Access OpenAccess
Notes ; The computational resources and services used for the first-principles calculations in this work were provided by the VSC (Flemish Supercomputer Center), funded by the Flemish Science Foundation (FWO-VI). T. P. is supported by a postdoctoral research fellowship from BOF-UAntwerpen. ; Approved Most recent IF: 6.337
Call Number UA @ admin @ c:irua:175014 Serial 6700
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Author Samaee, V.; Sandfeld, S.; Idrissi, H.; Groten, J.; Pardoen, T.; Schwaiger, R.; Schryvers, D.
Title Dislocation structures and the role of grain boundaries in cyclically deformed Ni micropillars Type A1 Journal article
Year 2020 Publication Materials Science And Engineering A-Structural Materials Properties Microstructure And Processing Abbreviated Journal Mat Sci Eng A-Struct
Volume 769 Issue Pages 138295
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Transmission electron microscopy and finite element-based dislocation simulations were combined to study the development of dislocation microstructures after cyclic deformation of single crystal and bicrystal Ni micropillars oriented for multi-slip. A direct correlation between large accumulation of plastic strain and the presence of dislocation cell walls in the single crystal micropillars was observed, while the presence of the grain boundary hampered the formation of wall-like structures in agreement with a smaller accumulated plastic strain. Automated crystallographic orientation and nanostrain mapping using transmission electron microscopy revealed the presence of lattice heterogeneities associated to the cell walls including long range elastic strain fields. By combining the nanostrain mapping with an inverse modelling approach, information about dislocation density, line orientation and Burgers vector direction was derived, which is not accessible otherwise in such dense dislocation structures. Simulations showed that the image forces associated with the grain boundary in this specific bicrystal configuration have only a minor influence on dislocation behavior. Thus, the reduced occurrence of “mature” cell walls in the bicrystal can be attributed to the available volume, which is too small to accommodate cell structures.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000500373800018 Publication Date 2019-08-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-5093 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 6.4 Times cited 1 Open Access OpenAccess
Notes Financial support from the Flemish (FWO) and German Research Foundation (DFG) through the European M-ERA.NET project “FaSS” (Fatigue Simulation near Surfaces) under the grant numbers GA.014.13 N,SCHW855/5-1, and SA2292/2-1 is gratefully acknowledged. V.S. acknowledges the FWO research project G012012 N “Understanding nanocrystalline mechanical behaviour from structural investigations”. H.I. is mandated by the Belgian National Fund for Scientific Research (FSR-FNRS). S.S. acknowledges financial support from the European Research Council through the ERC Grant Agreement No. 759419 (MuDiLingo – A Multiscale Dislocation Language for Data- Driven Materials Science). Approved Most recent IF: 6.4; 2020 IF: 3.094
Call Number EMAT @ emat @c:irua:163475 Serial 5371
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Author Yang, M.; Chen, H.; Orekhov, A.; Lu, Q.; Lan, X.; Li, K.; Zhang, S.; Song, M.; Kong, Y.; Schryvers, D.; Du, Y.
Title Quantified contribution of β″ and β′ precipitates to the strengthening of an aged Al–Mg–Si alloy Type A1 Journal article
Year 2020 Publication Materials Science And Engineering A-Structural Materials Properties Microstructure And Processing Abbreviated Journal Mat Sci Eng A-Struct
Volume 774 Issue Pages 138776
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract It is generally believed that β00 precipitates, rather than β0 precipitates, are the major strengthening precipitates in

aged Al–Mg–Si alloys. The reason for this difference is not well understood. To clarify this, two samples of the

same Al–Mg–Si alloy but with different aging states were prepared. The under-aged sample only contains nanoprecipitates

of the β00 type, while the peak-aged one contains nearly equal volumes of β00 and β0 precipitates. We

have, for the first time, separated the strengthening effect of the contribution from βʺ and βʹ precipitates,

respectively, by an indirect approach based on high-precision measurements of volume fractions, number densities,

sizes, proportions of the precipitates, their lattice strains, the composition and grain size of the matrix. The

β0 precipitates, which take 45.6% of the total precipitate volume in the peak-aged sample, contribute to the entire

precipitation strengthening by only 31.6%. The main reason why they are less useful compared to β00 precipitates

has been found to be associated with their smaller lattice strains relative to the matrix, which is 0.99% versus

2.10% (for β00 ).
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000514747200001 Publication Date 2019-12-04
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-5093 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 6.4 Times cited Open Access OpenAccess
Notes National Natural Science Foundation of China, 51531009 51711530713 51501230 ; Central South University, 2018gczd033 ; Flemish Science Foundation, VS.026.18N ; Program for Guangdong Introducing Innovative and Entrepreneurial Teams, 2016ZT06G025 ; Guangdong Natural Science Foundation, 2017B030306014 ; Approved Most recent IF: 6.4; 2020 IF: 3.094
Call Number EMAT @ emat @c:irua:165290 Serial 5440
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Author Spreitzer, M.; Klement, D.; Egoavil, R.; Verbeeck, J.; Kovac, J.; Zaloznik, A.; Koster, G.; Van Tendeloo, G.; Suvorov, D.; Rijnders, G.
Title Growth mechanism of epitaxial SrTiO3 on a (1 x 2) + (2 x 1) reconstructed Sr(1/2 ML)/Si(001) surface Type A1 Journal article
Year 2020 Publication Journal Of Materials Chemistry C Abbreviated Journal J Mater Chem C
Volume 8 Issue 2 Pages 518-527
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Sub-monolayer control over the growth at silicon-oxide interfaces is a prerequisite for epitaxial integration of complex oxides with the Si platform, enriching it with a variety of functionalities. However, the control over this integration is hindered by the intense reaction of the constituents. The most suitable buffer material for Si passivation is metallic strontium. When it is overgrown with a layer of SrTiO3 (STO) it can serve as a pseudo-substrate for the integration with functional oxides. In our study we determined a mechanism for epitaxial integration of STO with a (1 x 2) + (2 x 1) reconstructed Sr(1/2 ML)/Si(001) surface using all-pulsed laser deposition (PLD) technology. A detailed analysis of the initial deposition parameters was performed, which enabled us to develop a complete protocol for integration, taking into account the peculiarities of the PLD growth, STO critical thickness, and process thermal budget, in order to kinetically trap the reaction between STO and Si and thus to minimize the thickness of the interface layer. The as-prepared oxide layer exhibits STO(001)8Si(001) out-of-plane and STO[110]8Si[100] in-plane orientation and together with recent advances in large-scale PLD tools these results represent a new technological solution for the implementation of oxide electronics on demand.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000506852400036 Publication Date 2019-10-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2050-7526; 2050-7534 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 6.4 Times cited 12 Open Access OpenAccess
Notes ; The research was financially supported by the Slovenian Research Agency (Project No. P2-0091, J2-9237) and Ministry of Education, Science and Sport of the Republic of Slovenia (SIOX projects). This work was also funded by the European Union Council under the 7th Framework Program grant no. NMP3-LA-2010-246102 IFOX. J. V. and G. V. T. acknowledge funding from the Fund for Scientific Research Flanders under project no. G.0044.13N. ; Approved Most recent IF: 6.4; 2020 IF: 5.256
Call Number UA @ admin @ c:irua:165672 Serial 6298
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Author Vishwakarma, M.; Batra, Y.; Hadermann, J.; Singh, A.; Ghosh, A.; Mehta, B.R.
Title Exploring the role of graphene oxide as a co-catalyst in the CZTS photocathodes for improved photoelectrochemical properties Type A1 Journal article
Year 2022 Publication ACS applied energy materials Abbreviated Journal
Volume 5 Issue 6 Pages 7538-7549
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract The hydrogen evolution properties of CZTS heterostructure photocathodes are reported with graphene oxide (GO) as a co-catalyst layer coated by a drop-cast method and an Al2O3 protection layer fabricated using atomic layer deposition. In the CZTS absorber, a minor deviation from stoichiometry across the cross section of the thin film results in nanoscale growth of spurious phases, but the kesterite phase remains the dominant phase. We have investigated the band alignment parameters such as the band gap, work function, and Fermi level position that are crucial for making kesterite-based heterostructure devices. The photocurrent density in the photocathode CZTS/CdS/ZnO is found to be improved to -4.71 mAmiddotcm(-2) at -0.40 V-RHE, which is 3 times that of the pure CZTS. This enhanced photoresponse can be attributed to faster carrier separation at p-n junction regions driven by upward band bending at CZTS grain boundaries and the ZnO layer. GO as a co-catalyst over the heterostructure photocathode significantly improves the photocurrent density to -6.14 mAmiddotcm(-2) at -0.40 V-RHE by effective charge migration in the CZTS/CdS/ZnO/GO configuration, but the onset potential shifts only after application of the Al2O3 protection layer. Significant photocurrents of -29 mAmiddotcm(-2) at -0.40 V-RHE and -8 mAmiddotcm(-2) at 0 V-RHE are observed, with an onset potential of 0.7 V-RHE in CZTS/CdS/ZnO/GO/Al2O3. The heterostructure configuration and the GO co-catalyst reduce the charge-transfer resistance, while the Al2O3 top layer provides a stable photocurrent for a prolonged time (similar to 16 h). The GO co-catalyst increases the flat band potential from 0.26 to 0.46 V-RHE in CZTS/CdS/ZnO/GO, which supports the bias-induced band bending at the electrolyte-electrode interface.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000820418400001 Publication Date 2022-05-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2574-0962 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 6.4 Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: 6.4
Call Number UA @ admin @ c:irua:189666 Serial 7082
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Author Morsdorf, L.; Kashiwar, A.; Kübel, C.; Tasan, C.C.
Title Carbon segregation and cementite precipitation at grain boundaries in quenched and tempered lath martensite Type A1 Journal article
Year 2023 Publication Materials science and engineering: part A: structural materials: properties, microstructure and processing Abbreviated Journal
Volume 862 Issue Pages 144369-21
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Tempering is widely applied to make carbon atoms beneficially rearrange in high strength steel microstructures after quenching; though the nano-scale interaction of carbon atoms with crystallographic defects is hard to experimentally observe. To improve, we investigate the redistribution of carbon atoms along martensite grain boundaries in a quenched and tempered low carbon steel. We observe the tempering-induced microstructural evolution by in-situ heating in a transmission electron microscope (TEM) and by compositional analysis through atom probe tomography (APT). Probe volumes for APT originate from a single martensite packet but in different tempering conditions, which is achieved via a sequential lift-out with in-between tempering treatments. The complementary use of TEM and APT provides crystallographic as well as chemical information on carbon segregation and subsequent carbide precipitation at martensite grain boundaries. The results show that the amount of carbon segregation to martensite grain boundaries is influenced by the boundary type, e.g. low-angle lath or high-angle block boundaries. Also, the growth behavior of cementite precipitates from grain boundary nucleation sites into neighboring martensite grains differs at low- and high-angle grain boundaries. This is due to the crystallographic constraints arising from the semi-coherent orientation relationship between cementite and adjacent martensite. We also show that slower quenching stabilizes thin retained austenite films between martensite grains because of enhanced carbon segregation during cooling. Finally, we demonstrate the effect of carbon redistribution along martensite grain boundaries on the mechanical properties. Here, we compare micro-scale Vickers hardness results from boundary-containing probe volumes to nanoindentation results from pure bulk martensite (boundary-free) probe volumes.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000905165700001 Publication Date 2022-12-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-5093 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 6.4 Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: 6.4; 2023 IF: 3.094
Call Number UA @ admin @ c:irua:192279 Serial 7285
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Author Paulus, A.; Hendrickx, M.; Mayda, S.; Batuk, M.; Reekmans, G.; von Holst, M.; Elen, K.; Abakumov, A.M.; Adriaensens, P.; Lamoen, D.; Partoens, B.; Hadermann, J.; Van Bael, M.K.; Hardy, A.
Title Understanding the Activation of Anionic Redox Chemistry in Ti4+-Substituted Li2MnO3as a Cathode Material for Li-Ion Batteries Type A1 Journal article
Year 2023 Publication ACS applied energy materials Abbreviated Journal ACS Appl. Energy Mater.
Volume 6 Issue 13 Pages 6956-6971
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract Layered Li-rich oxides, demonstrating both cationic and anionic redox chemistry being used as positive electrodes for Li-ion batteries,have raised interest due to their high specific discharge capacities exceeding 250 mAh/g. However, irreversible structural transformations triggered by anionic redox chemistry result in pronounced voltagefade (i.e., lowering the specific energy by a gradual decay of discharge potential) upon extended galvanostatic cycling. Activating or suppressing oxygen anionic redox through structural stabilization induced by redox-inactivecation substitution is a well-known strategy. However, less emphasishas been put on the correlation between substitution degree and theactivation/suppression of the anionic redox. In this work, Ti4+-substituted Li2MnO3 was synthesizedvia a facile solution-gel method. Ti4+ is selected as adopant as it contains no partially filled d-orbitals. Our study revealedthat the layered “honeycomb-ordered” C2/m structure is preserved when increasing the Ticontent to x = 0.2 in the Li2Mn1-x Ti (x) O-3 solidsolution, as shown by electron diffraction and aberration-correctedscanning transmission electron microscopy. Galvanostatic cycling hintsat a delayed oxygen release, due to an improved reversibility of theanionic redox, during the first 10 charge-discharge cyclesfor the x = 0.2 composition compared to the parentmaterial (x = 0), followed by pronounced oxygen redoxactivity afterward. The latter originates from a low activation energybarrier toward O-O dimer formation and Mn migration in Li2Mn0.8Ti0.2O3, as deducedfrom first-principles molecular dynamics (MD) simulations for the“charged” state. Upon lowering the Ti substitution to x = 0.05, the structural stability was drastically improvedbased on our MD analysis, stressing the importance of carefully optimizingthe substitution degree to achieve the best electrochemical performance.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001018266700001 Publication Date 2023-07-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2574-0962 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 6.4 Times cited Open Access Not_Open_Access: Available from 24.12.2023
Notes Universiteit Hasselt, AUHL/15/2 – GOH3816N ; Russian Science Foundation, 20-43-01012 ; Fonds Wetenschappelijk Onderzoek, AUHL/15/2 – GOH3816N G040116N ; The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center) and the HPC infrastructure of the University of Antwerp (CalcUA), both funded by the FWO Vlaanderen and the Flemish Government-department EWI. Approved Most recent IF: 6.4; 2023 IF: NA
Call Number EMAT @ emat @c:irua:198160 Serial 8809
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Author Delvaux, A.; Lumbeeck, G.; Idrissi, H.; Proost, J.
Title Effect of microstructure and internal stress on hydrogen absorption into Ni thin film electrodes during alkaline water electrolysis Type A1 Journal article
Year 2020 Publication Electrochimica Acta Abbreviated Journal Electrochim Acta
Volume 340 Issue Pages 135970-10
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Efforts to improve the cell efficiency of hydrogen production by water electrolysis continue to address the electrochemical kinetics of the oxygen and hydrogen evolution reactions in detail. The objective of this work is to study a parasitic reaction occurring during the hydrogen evolution reaction (HER), namely the absorption of hydrogen atoms into the bulk electrode. Effects of the electrode microstructure and internal stress on this reaction have been addressed as well in this paper. Ni thin film samples were deposited on a Si substrate by sputter deposition with different deposition pressures, resulting in different microstructures and varying levels of internal stress. These microstructures were first analyzed in detail by Transmission Electron Microscopy (TEM). Cathodic chrono-amperometric measurements and cyclic voltammetries have then been performed in a homemade electrochemical cell. These tests were coupled to a multi-beam optical sensor (MOS) in order to obtain in-situ curvature measurements during hydrogen absorption. Indeed, since hydrogen absorption in the thin film geometry results in a constrained volume expansion, internal stress generation during HER can be monitored by means of curvature measurements. Our results show that different levels of internal stress, grain size and twin boundary density can be obtained by varying the deposition parameters. From an electrochemical point of view, this paper highlights the fact that the electrochemical surface mechanisms during HER are the same for all the electrodes, regardless of their microstructure. However it is shown that the absolute amount of hydrogen being absorbed into the Ni thin films increases when the grain size is reduced, due to a higher grain boundaries density which are favourite absorption sites for hydrogen. At the same time, it was concluded that H-2 evolution is favoured at electrodes having a more compressive (i.e. a less tensile) internal stress. Finally, the subtle effect of microstructure on the hydrogen absorption rate will be discussed as well. (C) 2020 Elsevier Ltd. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000521531800011 Publication Date 2020-02-26
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0013-4686 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 6.6 Times cited 2 Open Access Not_Open_Access
Notes ; The authors gratefully acknowledge financial support of the Public Service of Wallonia e Department of Energy and Sustainable Building, through the project WallonHY. The ACOM-TEM work was supported by the Hercules Foundation [Grant No. AUHA13009], the Flemish Research Fund (FWO) [Grant No. G.0365.15 N], and the Flemish Strategic Initiative for Materials (SIM) under the project InterPoCo. We also like to cordially thank Ronny Santoro for carrying out the ICP-OES measurements. ; Approved Most recent IF: 6.6; 2020 IF: 4.798
Call Number UA @ admin @ c:irua:168536 Serial 6497
Permanent link to this record
 

 
Author Hamon, A.-L.; Verbeeck, J.; Schryvers, D.; Benedikt, J.; van den Sanden, R.M.C.M.
Title ELNES study of carbon K-edge spectra of plasma deposited carbon films Type A1 Journal article
Year 2004 Publication Journal of materials chemistry Abbreviated Journal J Mater Chem
Volume 14 Issue Pages 2030-2035
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract Electron energy loss spectroscopy was used to investigate the bonding of plasma deposited carbon films. The experimental conditions include the use of a specific collection angle for which the shape of the spectra is free of the orientation dependency usually encountered in graphite due to its anisotropic structure. The first quantification process of the energy loss near-edge structure was performed by a standard fit of the collected spectrum, corrected for background and multiple scattering, with three Gaussian functions followed by a comparison with the graphite spectrum obtained under equivalent experimental conditions. In a second approach a fitting model directly incorporating the background subtraction and multiple scattering removal was applied. The final numerical results are interpreted in view of the deposition conditions of the films and the actual fitting procedure with the related choice of parameters.
Address
Corporate Author Thesis
Publisher Place of Publication Cambridge Editor
Language Wos 000222312500017 Publication Date 2004-06-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0959-9428;1364-5501; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 6.626 Times cited 61 Open Access
Notes Approved Most recent IF: NA
Call Number UA @ lucian @ c:irua:48782UA @ admin @ c:irua:48782 Serial 1025
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Author Payne, L.M.; Albrecht, W.; Langbein, W.; Borri, P.
Title The optical nanosizer – quantitative size and shape analysis of individual nanoparticles by high-throughput widefield extinction microscopy Type A1 Journal article
Year 2020 Publication Nanoscale Abbreviated Journal Nanoscale
Volume Issue Pages
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Nanoparticles are widely utilised for a range of applications, from catalysis to medicine, requiring accurate knowledge of their size and shape. Current techniques for particle characterisation are either not very accurate or time consuming and expensive. Here we demonstrate a rapid and quantitative method for particle analysis based on measuring the polarisation-resolved optical extinction cross-section of hundreds of individual nanoparticles using wide-field microscopy, and determining the particle size and shape from the optical properties. We show measurements on three samples consisting of nominally spherical gold nanoparticles of 20 nm and 30 nm diameter, and gold nanorods of 30 nm length and 10 nm diameter. Nanoparticle sizes and shapes in three dimensions are deduced from the measured optical cross-sections at different wavelengths and light polarisation, by solving the inverse problem, using an ellipsoid model of the particle polarisability in the dipole limit. The sensitivity of the method depends on the experimental noise and the choice of wavelengths. We show an uncertainty down to about 1 nm in mean diameter, and 10% in aspect ratio when using two or three color channels, for a noise of about 50 nm<sup>2</sup>in the measured cross-section. The results are in good agreement with transmission electron microscopy, both 2D projection and tomography, of the same sample batches. Owing to its combination of experimental simplicity, ease of access to statistics over many particles, accuracy, and geometrical particle characterisation in 3D, this “optical nanosizer” method has the potential to become the technique of choice for quality control in next-generation particle manufacturing.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000558928800022 Publication Date 2020-07-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2040-3364 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 6.7 Times cited Open Access OpenAccess
Notes This work was supported by a Welsh Government Life Sciences Bridging Fund (grant LSBF/R6-005) and by the UK EPSRC (grant no. EP/I005072/1 and EP/M028313/1). PB acknowledges the Royal Society for her Wolfson research merit award (grant WM140077). The authors acknowledge funding from the European Commission (Grant EUSMI E191000350). WA acknowledges an Individual Fellowship from the Marie Sklodowska-Curie actions (MSCA) under the EU’s Horizon 2020 program (Grant 797153, SOPMEN), and Sara Bals for supporting the STEM measurements. The bright-field TEM was performed by Thomas Davies at Cardiff University. We acknowledge Attilio Zilli for helpful discussions and contributions in calculating the relative field strengths in the illumination and finite-element simulation of cross-sections shown in the ESI.† We acknowledge Iestyn Pope for technical support of the optical equipment. Approved Most recent IF: 6.7; 2020 IF: 7.367
Call Number UA @ lucian @c:irua:170485 Serial 6397
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Author Vishwakarma, M.; Agrawal, K.; Hadermann, J.; Mehta, B.R.
Title Investigating the effect of sulphurization on volatility of compositions in Cu-poor and Sn-rich CZTS thin films Type A1 Journal article
Year 2020 Publication Applied Surface Science Abbreviated Journal Appl Surf Sci
Volume 507 Issue Pages 145043
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract In the present work, the Cu-poor and Sn-rich CZTS thin films were prepared in order to study the volatility of Sn with respect to other components. Thin film compositions were kept intentionally Sn-rich to understand the behaviour of loss and segregation of Sn during sulphurization. The homogeneous composition distribution in precursor thin films turns heterogeneous with a change in morphology after sulphurization. The inability of identifying nanoscale secondary phases in CZTS thin film by conventional analytical techniques such as XRD and Raman, can be fulfilled by employing HAADF-STEM analysis. XPS and HAADF-STEM analyses provide the quantification of nanoscale secondary phases across the thin film and surface, respectively. The volatility of Sn was revealed in the form of segregation in the middle layer of CZTS cross-sectional lamella rather than loss to annealing atmosphere. It was observed that among the cations of CZTS, Sn segregates more than Cu, while Zn segregates least. The nanoscale spurious phases were observed to vary across different regions in the sulphurized CZTS sample. The reactive annealing lead to grain growth and formation of grain boundary features in the CZTS thin films, where annealing significantly modifies the potential difference and band bending at grain boundaries with respect to intra-grains.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000520021200053 Publication Date 2019-12-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0169-4332 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 6.7 Times cited 4 Open Access OpenAccess
Notes ; Authors acknowledges support provided by DST, India in the forms of InSOL project. We also acknowledge Dr. Indrani Mishra for XPS measurements and DST-FIST Raman facility for Raman measurements. Manoj Vishwakarma acknowledges IIT Delhi, New Delhi, India for MHRD fellowship. Prof. B.R. Mehta acknowledges the support of the Schlumberger chair professorship. ; Approved Most recent IF: 6.7; 2020 IF: 3.387
Call Number UA @ admin @ c:irua:168603 Serial 6552
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Author Van Dijck, J.G.; Mampuys, P.; Ching, H.Y.V.; Krishnan, D.; Baert, K.; Hauffman, T.; Verbeeck, J.; Van Doorslaer, S.; Maes, B.U.W.; Dorbec, M.; Buekenhoudt, A.; Meynen, V.
Title Synthesis – properties correlation and the unexpected role of the titania support on the Grignard surface modification Type A1 Journal article
Year 2020 Publication Applied Surface Science Abbreviated Journal Appl Surf Sci
Volume 527 Issue Pages 146851-17
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Laboratory of adsorption and catalysis (LADCA); Organic synthesis (ORSY); Applied Electrochemistry & Catalysis (ELCAT)
Abstract While the impact of reaction conditions on surface modification with Grignard reactants has been studied for silica supports, such information is absent for metal oxides like titania. Differences between modified titania and silica are observed, making it paramount to explore the reaction mechanism. A detailed study on the impact of the reaction conditions is reported, with a focus on the chain length of the alkyl Grignard reactant, its concentration, the reaction time and temperature, and the type of titania support. While the increase in the chain length reduces the amount of organic groups on the surface, the concentration, time and temperature show little/no influence on the modification degree. However, the type of titania support used and the percentage of amorphous phase present has a significant impact on the amount of grafted groups. Even though the temperature and concentration show no clear impact on the modification degree, they can cause changes in the surface hydroxyl population, which are thus not linked to the modification degree. Furthermore, the titania support is reduced during functionalization. This reduction dependents on the reaction temperature, the titania support and the chain length of the Grignard reactant. Similarly, this reduction is not linked to the modification degree.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000564205300003 Publication Date 2020-06-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0169-4332 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 6.7 Times cited 5 Open Access OpenAccess
Notes ; The FWO (Fonds Wetenschappelijk Onderzoek) is gratefully acknowledged for the VITO-FWO grant of fellow Jeroen G. Van Dijck (11W9416N) and the financial support granted in project GO12712N. The E.U. is acknowledged for H.Y. Vincent Ching's H2020-MSCA-IF (grant number 792946, iSPY). Dileep Krishnan and Johan Verbeeck acknowledge funding from GOA project “solarpaint” of the University of Antwerp. ; Approved Most recent IF: 6.7; 2020 IF: 3.387
Call Number UA @ admin @ c:irua:169722 Serial 6712
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Author Fatermans, J.; Romolini, G.; Altantzis, T.; Hofkens, J.; Roeffaers, M.B.J.; Bals, S.; Van Aert, S.
Title Atomic-scale detection of individual lead clusters confined in Linde Type A zeolites Type A1 Journal article
Year 2022 Publication Nanoscale Abbreviated Journal Nanoscale
Volume Issue Pages
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT)
Abstract Structural analysis of metal clusters confined in nanoporous materials is typically performed by X-ray-driven techniques. Although X-ray analysis has proved its strength in the characterization of metal clusters, it provides averaged structural information. Therefore, we here present an alternative workflow for bringing the characterization of confined metal clusters towards the local scale. This workflow is based on the combination of aberration-corrected transmission electron microscopy (TEM), TEM image simulations, and powder X-ray diffraction (XRD) with advanced statistical techniques. In this manner, we were able to characterize the clustering of Pb atoms in Linde Type A (LTA) zeolites with Pb loadings as low as 5 wt%. Moreover, individual Pb clusters could be directly detected. The proposed methodology thus enables a local-scale characterization of confined metal clusters in zeolites. This is important for further elucidation of the connection between the structure and the physicochemical properties of such systems.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000809619900001 Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2040-3364 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 6.7 Times cited 2 Open Access OpenAccess
Notes The authors acknowledge the Research Foundation Flanders through project fundings (FWO, G026718N, G050218N, ZW15_09-G0H6316N, and W002221N) and through a PhD scholarship to G.R. (grant 11C6920N), as well as iBOF-21-085 PERSIST. T.A. and S.V.A. acknowledge funding from the University of Antwerp Research fund (BOF). J.H. acknowledges the Flemish government through long-term structural funding Methusalem (CASAS2, Meth/15/04) and the MPI as MPI fellow. M.R. acknowledges funding by the KU Leuven Research Fund (C14/19/079). S.B. and S.V.A. acknowledge funding from the European Research Council under the European Union’s Horizon 2020 research and innovation program (ERC Consolidator Grants No. 815128−REALNANO and No. 770887−PICOMETRICS). The authors thank Dr. D. Chernyshov for the collection of XRD measurements. Approved Most recent IF: 6.7
Call Number EMAT @ emat @c:irua:189061 Serial 7076
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Author Wang, Y.; Sztranyovszky, Z.; Zilli, A.; Albrecht, W.; Bals, S.; Borri, P.; Langbein, W.
Title Quantitatively linking morphology and optical response of individual silver nanohedra Type A1 Journal article
Year 2022 Publication Nanoscale Abbreviated Journal Nanoscale
Volume 14 Issue 30 Pages 11028-11037
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract The optical response of metal nanoparticles is governed by plasmonic resonances, which are dictated by the particle morphology. A thorough understanding of the link between morphology and optical response requires quantitatively measuring optical and structural properties of the same particle. Here we present such a study, correlating electron tomography and optical micro-spectroscopy. The optical measurements determine the scattering and absorption cross-section spectra in absolute units, and electron tomography determines the 3D morphology. Numerical simulations of the spectra for the individual particle geometry, and the specific optical set-up used, allow for a quantitative comparison including the cross-section magnitude. Silver nanoparticles produced by photochemically driven colloidal synthesis, including decahedra, tetrahedra and bi-tetrahedra are investigated. A mismatch of measured and simulated spectra is found in some cases when assuming pure silver particles, which is explained by the presence of a few atomic layers of tarnish on the surface, not evident in electron tomography. The presented method tightens the link between particle morphology and optical response, supporting the predictive design of plasmonic nanomaterials.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000828704000001 Publication Date 2022-07-15
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; WoS citing articles
Impact Factor (up) 6.7 Times cited 1 Open Access OpenAccess
Notes Z.S. acknowledges the UK Engineering and Physical Sciences Research Council (EPSRC) for his Ph.D. studentship award (grant EP/R513003/1). Y.W. acknowledges Iwan Moreels (University of Ghent) for training in nanoparticle synthesis. Y.W. acknowledges the Biotechnology and Biological Sciences Research Council (BBSRC) for his Ph.D. studentship award (grant BB/L015889/1). This work was supported by the UK EPSRC (grants EP/I005072/1 and EP/M028313/1), and by the European Commission (EUSMI E191000350). W.A. acknowledges an Individual Fellowship from the Marie Skodowska-Curie actions (MSCA) under the EU's Horizon 2020 program (Grant 797153, SOPMEN). We thank Lukas Payne and Iestyn Pope for contributions to the development of the hardware and software used for the optical measurements. Approved Most recent IF: 6.7
Call Number UA @ admin @ c:irua:189578 Serial 7092
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Author Frolov, A.S.; Callaert, C.; Batuk, M.; Hadermann, J.; Volykhov, A.A.; Sirotina, A.P.; Amati, M.; Gregoratti, L.; Yashina, L.V.
Title Nanoscale phase separation in the oxide layer at GeTe (111) surfaces Type A1 Journal article
Year 2022 Publication Nanoscale Abbreviated Journal Nanoscale
Volume 14 Issue 35 Pages 12918-12927
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract As a semiconductor ferroelectric, GeTe has become a focus of renewed attention due to the recent discovery of giant Rashba splitting. It already has a wide range of applications, from thermoelectricity to data storage. Its stability in ambient air, as well as the structure and properties of an oxide layer, define the processing media for device production and operation. Here, we studied a reaction between the GeTe (111) surface and molecular oxygen for crystals having solely inversion domains. We evaluated the reaction kinetics both ex situ and in situ using NAP XPS. The structure of the oxide layer is extensively discussed, where, according to HAADF-STEM and STEM-EDX, nanoscale phase separation of GeO2 and Te is observed, which is unusual for semiconductors. We believe that such behaviour is closely related to the ferroelectric properties and the domain structure of GeTe.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000847743300001 Publication Date 2022-08-25
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 (up) 6.7 Times cited Open Access Not_Open_Access
Notes Approved Most recent IF: 6.7
Call Number UA @ admin @ c:irua:190665 Serial 7181
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Author Craig, T.M.; Kadu, A.A.; Batenburg, K.J.; Bals, S.
Title Real-time tilt undersampling optimization during electron tomography of beam sensitive samples using golden ratio scanning and RECAST3D Type A1 Journal article
Year 2023 Publication Nanoscale Abbreviated Journal
Volume 15 Issue 11 Pages 5391-5402
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Electron tomography is a widely used technique for 3D structural analysis of nanomaterials, but it can cause damage to samples due to high electron doses and long exposure times. To minimize such damage, researchers often reduce beam exposure by acquiring fewer projections through tilt undersampling. However, this approach can also introduce reconstruction artifacts due to insufficient sampling. Therefore, it is important to determine the optimal number of projections that minimizes both beam exposure and undersampling artifacts for accurate reconstructions of beam-sensitive samples. Current methods for determining this optimal number of projections involve acquiring and post-processing multiple reconstructions with different numbers of projections, which can be time-consuming and requires multiple samples due to sample damage. To improve this process, we propose a protocol that combines golden ratio scanning and quasi-3D reconstruction to estimate the optimal number of projections in real-time during a single acquisition. This protocol was validated using simulated and realistic nanoparticles, and was successfully applied to reconstruct two beam-sensitive metal–organic framework complexes.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000937908900001 Publication Date 2023-02-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2040-3364 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 6.7 Times cited 1 Open Access OpenAccess
Notes H2020 European Research Council, 815128 ; H2020 Marie Skłodowska-Curie Actions, 860942 ; Approved Most recent IF: 6.7; 2023 IF: 7.367
Call Number EMAT @ emat @c:irua:195235 Serial 7260
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Author Li, C.-F.; Chen, L.-D.; Wu, L.; Liu, Y.; Hu, Z.-Y.; Cui, W.-J.; Dong, W.-D.; Liu, X.; Yu, W.-B.; Li, Y.; Van Tendeloo, G.; Su, B.-L.
Title Directly revealing the structure-property correlation in Na+-doped cathode materials Type A1 Journal article
Year 2023 Publication Applied surface science Abbreviated Journal
Volume 612 Issue Pages 155810-10
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The introduction of Na+ is considered as an effective way to improve the performance of Ni-rich cathode materials. However, the direct structure-property correlation for Na+ doped NCM-based cathode materials remain unclear, due to the difficulty of local and accurate structural characterization for light elements such as Li and Na. Moreover, there is the complexity of the modeling for the whole Li ion battery (LIB) system. To tackle the above-mentioned issues, we prepared Na+-doped LiNi0.6Co0.2Mn0.2O2 (Na-NCM622) material. The crystal structure change and the lattice distortion with picometers precision of the Na+-doped material is revealed by Cs-corrected scanning transmission electron microscopy (STEM). Density functional theory (DFT) and the recently proposed electrochemical model, i.e., modified Planck-Nernst-Poisson coupled Frumkin-Butler-Volmer (MPNP-FBV), has been applied to reveal correlations between the activation energy and the charge transfer resistance at multiscale. It is shown that Na+ doping can reduce the activation energy barrier from. G = 1.10 eV to 1.05 eV, resulting in a reduction of the interfacial resistance from 297 O to 134 Omega. Consequently, the Na-NCM622 cathode delivers a superior capacity retention of 90.8 % (159 mAh.g(-1)) after 100 cycles compared to the pristine NCM622 (67.5 %, 108 mAh.g(-1)). Our results demonstrate that the kinetics of Li+ diffusion and the electrochemical reaction can be enhanced by Na+ doping the cathode material.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000892940300001 Publication Date 2022-11-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0169-4332 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 6.7 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 6.7; 2023 IF: 3.387
Call Number UA @ admin @ c:irua:192758 Serial 7296
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Author Smeyers, R.; Milošević, M.V.; Covaci, L.
Title Strong gate-tunability of flat bands in bilayer graphene due to moiré encapsulation between hBN monolayers Type A1 Journal article
Year 2023 Publication Nanoscale Abbreviated Journal
Volume 15 Issue 9 Pages 4561-4569
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract When using hexagonal boron-nitride (hBN) as a substrate for graphene, the resulting moire pattern creates secondary Dirac points. By encapsulating a multilayer graphene within aligned hBN sheets the controlled moire stacking may offer even richer benefits. Using advanced tight-binding simulations on atomistically-relaxed heterostructures, here we show that the gap at the secondary Dirac point can be opened in selected moire-stacking configurations, and is independent of any additional vertical gating of the heterostructure. On the other hand, gating can broadly tune the gap at the principal Dirac point, and may thereby strongly compress the first moire mini-band in width against the moire-induced gap at the secondary Dirac point. We reveal that in hBN-encapsulated bilayer graphene this novel mechanism can lead to isolated bands flatter than 10 meV under moderate gating, hence presenting a convenient pathway towards electronically-controlled strongly-correlated states on demand.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000933052600001 Publication Date 2023-02-07
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; WoS citing articles
Impact Factor (up) 6.7 Times cited Open Access OpenAccess
Notes Approved Most recent IF: 6.7; 2023 IF: 7.367
Call Number UA @ admin @ c:irua:195249 Serial 7340
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Author Benedet, M.; Andrea Rizzi, G.; Gasparotto, A.; Gauquelin, N.; Orekhov, A.; Verbeeck, J.; Maccato, C.; Barreca, D.
Title Functionalization of graphitic carbon nitride systems by cobalt and cobalt-iron oxides boosts solar water oxidation performances Type A1 Journal article
Year 2023 Publication Applied surface science Abbreviated Journal
Volume 618 Issue Pages 156652
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The ever-increasing energy demand from the world population has made the intensive use of fossil fuels an overarching threat to global environment and human health. An appealing alternative is offered by sunlight-assisted photoelectrochemical water splitting to yield carbon-free hydrogen fuel, but kinetic limitations associated to the oxygen evolution reaction (OER) render the development of cost-effective, eco-friendly and stable electrocatalysts an imperative issue. In the present work, OER catalysts based on graphitic carbon nitride (g-C3N4) were deposited on conducting glass substrates by a simple decantation procedure, followed by functionalization with low amounts of nanostructured CoO and CoFe2O4 by radio frequency (RF)-sputtering, and final annealing under inert atmosphere. A combination of advanced characterization tools was used to investigate the interplay between material features and electrochemical performances. The obtained results highlighted the formation of a p-n junction for the g-C3N4-CoO system, whereas a Z-scheme junction accounted for the remarkable performance enhancement yielded by g-C3N4-CoFe2O4. The intimate contact between the system components also afforded an improved electrocatalyst stability in comparison to various bare and functionalized g-C3N4-based systems. These findings emphasize the importance of tailoring g-C3N4 chemico-physical properties through the dispersion of complementary catalysts to fully exploit its applicative potential.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000950654300001 Publication Date 2023-02-04
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0169-4332 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 6.7 Times cited 11 Open Access OpenAccess
Notes The authors gratefully acknowledge financial support from CNR (Progetti di Ricerca @CNR – avviso 2020 – ASSIST), Padova University (P-DiSC#04BIRD2020-UNIPD EUREKA, DOR 2020–2022), AMGA Foundation (NYMPHEA project), INSTM Consortium (INSTM21PDGASPAROTTO – NANOMAT, INSTM21PDBARMAC – ATENA) and the European Union's Horizon 2020 research and innovation program under grant agreement No 823717 – ESTEEM3. The FWO-Hercules fund G0H4316N 'Direct electron detector for soft matter TEM' is also acknowledged. Many thanks are due to Prof. Luca Gavioli (Università Cattolica del Sacro Cuore, Brescia, Italy) and Dr. Riccardo Lorenzin (Department of Chemical Sciences, Padova University, Italy) for their invaluable technical support.; esteem3reported; esteem3TA Approved Most recent IF: 6.7; 2023 IF: 3.387
Call Number EMAT @ emat @c:irua:196150 Serial 7376
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Author Conti, S.; Chaves, A.; Pandey, T.; Covaci, L.; Peeters, F.M.; Neilson, D.; Milošević, M.V.
Title Flattening conduction and valence bands for interlayer excitons in a moire MoS₂/WSe₂ heterobilayer Type A1 Journal article
Year 2023 Publication Nanoscale Abbreviated Journal
Volume Issue Pages 1-11
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT)
Abstract We explore the flatness of conduction and valence bands of interlayer excitons in MoS2/WSe2 van der Waals heterobilayers, tuned by interlayer twist angle, pressure, and external electric field. We employ an efficient continuum model where the moire pattern from lattice mismatch and/or twisting is represented by an equivalent mesoscopic periodic potential. We demonstrate that the mismatch moire potential is too weak to produce significant flattening. Moreover, we draw attention to the fact that the quasi-particle effective masses around the Gamma-point and the band flattening are reduced with twisting. As an alternative approach, we show (i) that reducing the interlayer distance by uniform vertical pressure can significantly increase the effective mass of the moire hole, and (ii) that the moire depth and its band flattening effects are strongly enhanced by accessible electric gating fields perpendicular to the heterobilayer, with resulting electron and hole effective masses increased by more than an order of magnitude – leading to record-flat bands. These findings impose boundaries on the commonly generalized benefits of moire twistronics, while also revealing alternative feasible routes to achieve truly flat electron and hole bands to carry us to strongly correlated excitonic phenomena on demand.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001047512300001 Publication Date 2023-07-25
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; WoS citing articles
Impact Factor (up) 6.7 Times cited Open Access Not_Open_Access: Available from 25.01.2024
Notes Approved Most recent IF: 6.7; 2023 IF: 7.367
Call Number UA @ admin @ c:irua:198290 Serial 8819
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Author Hamon, C.; Novikov, S.M.; Scarabelli, L.; Solís, D.M.; Altantzis, T.; Bals, S.; Taboada, J.M.; Obelleiro, F.; Liz-Marzán, L.M.
Title Collective Plasmonic Properties in Few-Layer Gold Nanorod Supercrystals Type A1 Journal article
Year 2015 Publication ACS Photonics Abbreviated Journal Acs Photonics
Volume 2 Issue 2 Pages 1482-1488
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Gold nanorod supercrystals have been widely employed for the detection of relevant bioanalytes with detection limits ranging from nano- to picomolar levels,

confirming the promising nature of these structures for biosensing. Even though a relationship between the height of the supercrystal (i.e., the number of stacked nanorod layers)and the enhancement factor has been proposed, no systematic

study has been reported. In order to tackle this problem, we prepared gold nanorod supercrystals with varying numbers of stacked layers and analyzed them extensively by atomic force microscopy, electron microscopy and surface enhanced Raman scattering. The experimental results were compared to numerical

simulations performed on real-size supercrystals composed of thousands of nanorod building blocks. Analysis of the hot spot distribution in the simulated supercrystals showed the presence of standing waves that were distributed at different depths, depending on the number of layers in each supercrystal. On the basis of these theoretical results, we interpreted the experimental

data in terms of analyte penetration into the topmost layer only, which indicates that diffusion to the interior of the supercrystals would be crucial if the complete field enhancement produced by the stacked nanorods is to be exploited. We propose that our conclusions will be of high relevance in the design of next generation plasmonic devices.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000363435600013 Publication Date 2015-09-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2330-4022 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 6.756 Times cited 70 Open Access OpenAccess
Notes The authors are thankful to Dr. Luis Yate for assistance with sample preparation. This work was supported by the European Research Council (ERC Advanced Grant #267867 Plasmaquo and ERC Starting Grant #335078 Colouratom) and the Spanish Ministerio de Economía y Competitividad (MAT2013-46101-R). D.M.S., J.M.T., and F.O. acknowledge funding from the European Regional Development Fund (ERDF) and the Spanish Ministerio de Economiá y Competitividad (MAT2014-58201-C2-1-R, MAT2014-58201- C2-2-R, Project TACTICA), from the ERDF and the Galician Regional Government under Projects CN2012/279 and CN2012/260 (AtlantTIC) and the Plan I2C (2011−2015), and from the ERDF and the Extremadura Regional Government (Junta de Extremadura Project IB13185).; ECAS_Sara; (ROMEO:white; preprint:; postprint:restricted 12 months embargo; pdfversion:cannot); Approved Most recent IF: 6.756; 2015 IF: NA
Call Number c:irua:129458 Serial 3978
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Author Brodu, A.; Ballottin, M.V.; Buhot, J.; van Harten, E.J.; Dupont, D.; La Porta, A.; Prins, P.T.; Tessier, M.D.; Versteegh, M.A.M.; Zwiller, V.; Bals, S.; Hens, Z.; Rabouw, F.T.; Christianen, P.C.M.; de Donega, C.M.; Vanmaekelbergh, D.
Title Exciton Fine Structure and Lattice Dynamics in InP/ZnSe Core/Shell Quantum Dots Type A1 Journal article
Year 2018 Publication ACS Photonics Abbreviated Journal Acs Photonics
Volume 5 Issue 5 Pages 3353-3362
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Nanocrystalline InP quantum dots (QDs) hold promise for heavy-metal-free optoelectronic applications due to their bright and size tunable emission in the visible range. Photochemical stability and high photoluminescence (PL) quantum yield are obtained by a diversity of epitaxial shells around the InP core. To understand and optimize the emission line shapes, the exciton fine structure of InP core/shell QD systems needs be investigated. Here, we study the exciton fine structure of InP/ZnSe core/shell QDs with core diameters ranging from 2.9 to 3.6 nm (PL peak from 2.3 to 1.95 eV at 4 K). PL decay measurements as a function of temperature in the 10 mK to 300 K range show that the lowest exciton fine structure state is a dark state, from which radiative recombination is assisted by coupling to confined acoustic phonons with energies ranging from 4 to 7 meV, depending on the core diameter. Circularly polarized fluorescence line-narrowing (FLN) spectroscopy at 4 K under high magnetic fields (up to 30 T) demonstrates that radiative recombination from the dark F = +/- 2 state involves acoustic and optical phonons, from both the InP core and the ZnSe shell. Our data indicate that the highest intensity FLN peak is an acoustic phonon replica rather than a zero-phonon line, implying that the energy separation observed between the F = +/- 1 state and the highest intensity peak in the FLN spectra (6 to 16 meV, depending on the InP core size) is larger than the splitting between the dark and bright fine structure exciton states.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000442185900049 Publication Date 2018-07-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2330-4022 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 6.756 Times cited 40 Open Access OpenAccess
Notes ; We acknowledge the support of the HFML-RU/FOM, member of the European Magnetic Field Laboratory (EMFL). D.V. and Z.H. acknowledge support by the European Commission via the Marie-Sklodowska Curie action Phonsi (H2020-MSCA-ITN-642656) and the Marie Sklodowska-Curie Action Compass (H2020 MSCA-RISE-691185). Z.H. acknowledges the Research Foundation Flanders (project 17006602) and Ghent University (GOA no. 01G01513). Z.H. and S.B. acknowledge SIM vzw (SBO-QDOCCO). F.T.R. acknowledges financial support from The Netherlands Organisation for Scientific Research NWO (Gravitation program Multiscale Catalytic Energy Conversion and VENI grant number 722.017.002). This work was also supported by the Dutch NWO-Physics Program DDC13, ERC Advanced Grant 692691 “First step”, and ERC Starting Grant 335078 “COLOURATOM”. ; ecas_sara Approved Most recent IF: 6.756
Call Number UA @ lucian @ c:irua:153753UA @ admin @ c:irua:153753 Serial 5100
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Author Greboval, C.; Chu, A.; Vale Magalhaes, D.; Ramade, J.; Qu, J.; Rastogi, P.; Khalili, A.; Chee, S.-S.; Aubin, H.; Vincent, G.; Bals, S.; Delerue, C.; Lhuillier, E.
Title Ferroelectric gating of narrow band-gap nanocrystal arrays with enhanced light-matter coupling Type A1 Journal article
Year 2021 Publication Acs Photonics Abbreviated Journal Acs Photonics
Volume 8 Issue 1 Pages 259-268
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract As narrow band gap nanocrystals become a considerable building block for the design of infrared sensors, device design needs to match their actual operating conditions. While in the near and shortwave infrared, room-temperature operation has been demonstrated, longer wavelengths still require low-temperature operations and thus specific design. Here, we discuss how field-effect transistors (FETs) can be compatible with low-temperature detection. To reach this goal, two key developments are proposed. First, we report the gating of nanocrystal films from SrTiO3 which leads to high gate capacitance with leakage and breakdown free operation in the 4-100 K range. Second, we demonstrate that this FET is compatible with a plasmonic resonator whose role is to achieve strong light absorption from a thin film used as the channel of the FET. Combining three resonances, broadband absorption from 1.5 to 3 mu m reaching 30% is demonstrated. Finally, combining gate and enhanced light-matter coupling, we show that detectivity can be as high as 10(12) Jones for a device presenting a 3 mu m cutoff wavelength and 30 K operation.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000612567900028 Publication Date 2021-01-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2330-4022 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 6.756 Times cited 21 Open Access OpenAccess
Notes The project is supported by ERC Starting Grant BlackQD (Grant No. 756225) and Consolidator Grant Realnano (815128). This project has received funding from the European Commission (Grant 731019, EUSMI). We acknowledge the use of clean-room facilities from the “Centrale de ProximitéParis-Centre”. This work has been supported by the Region Ile-de-France in the framework of DIM Nano-K (Grant dopQD). This work was supported by French state funds managed by the ANR within the Investissements d’Avenir programme under Reference ANR-11-IDEX-0004-02 and, more specifically, within the framework of the Cluster of Excellence MATISSE and also by the Grant IPER-Nano2 (ANR-18CE30-0023-01), Copin (ANR-19-CE24-0022), Frontal (ANR-19-CE09-0017), Graskop (ANR-19-CE09-0026), and NITQuantum. J.Q. thanks Chinese Scholarship Council for Ph.D. Grant, while A.C. thanks Agence Innovation Defense.; sygma Approved Most recent IF: 6.756
Call Number UA @ admin @ c:irua:176708 Serial 6725
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Author Mushtaq, A.; Pradhan, B.; Kushavah, D.; Zhang, Y.; Wolf, M.; Schrenker, N.; Fron, E.; Bals, S.; Hofkens, J.; Debroye, E.; Pal, S.K.
Title Third-Order Nonlinear Optical Properties and Saturation of Two-Photon Absorption in Lead-Free Double Perovskite Nanocrystals under Femtosecond Excitation Type A1 Journal article
Year 2021 Publication Acs Photonics Abbreviated Journal Acs Photonics
Volume 8 Issue 11 Pages 3365-3374
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Lead halide perovskites have been widely explored

in the field of photovoltaics, light-emitting diodes, and lasers due to

their outstanding linear and nonlinear optical (NLO) properties.

But, the presence of lead toxicity and low chemical stability remain

serious concerns. Lead-free double perovskite with excellent

optical properties and chemical stability could be an alternative.

However, proper examination of the NLO properties of such a

material is crucial to identify their utility for future nonlinear device

applications. Herein, we have made use of femtosecond (fs) Z-scan

technique to explore the NLO properties of Cs2AgIn0.9Bi0.1Cl6

nanocrystals (NCs). Our measurements suggest that under

nonresonant fs excitation, perovskite NCs exhibit strong twophoton

absorption (TPA). The observed saturation of TPA at high

light intensities has been explained by a customized model. Furthermore, we have demonstrated a change in the nonlinear refractive

index of the NCs under varying input intensities. The strong TPA absorption of lead-free double perovskite NCs could be used for

Kerr nonlinearity-based nonlinear applications such as optical shutters for picosecond lasers.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 000757024100028 Publication Date 2021-11-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2330-4022 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor (up) 6.756 Times cited 25 Open Access OpenAccess
Notes A.M. is thankful to IIT Mandi for his fellowship and Advanced Materials Research Centre for the experimental facilities. A.M. is also thankful to Torbjörn Pascher (Pascher Instrument) for writing the Z-scan data acquisition program. J.H. acknowledges financial support from the Research Foundation-Flanders (FWO, Grant No. G983.19N, G0A5817N, and G0H6316N) and the Flemish government through long-term structural funding Methusalem (CASAS2, Meth/15/04). B.P. acknowledges postdoctoral fellowship from the Research Foundation- Flanders (FWO Grant No. 1275521N). D.K. acknowledges the financial support from Science and Engineering Research Board (Grant No. PDF/2018/003146), India. N.J.S. acknowledges financial support from the Research Foundation- Flanders via a postdoctoral fellowship (FWO Grant No. 1238622N). Approved Most recent IF: 6.756
Call Number EMAT @ emat @c:irua:184249 Serial 6832
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