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Records |
Links |
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Author |
Craig, T.M.; Kadu, A.A.; Batenburg, K.J.; Bals, S. |
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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 |
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| |
Volume |
15 |
Issue |
11 |
Pages |
5391-5402 |
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| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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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. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000937908900001 |
Publication Date |
2023-02-13 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
|
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| |
ISSN |
2040-3364 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
6.7 |
Times cited |
1 |
Open Access |
OpenAccess |
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Notes |
H2020 European Research Council, 815128 ; H2020 Marie Skłodowska-Curie Actions, 860942 ; |
Approved |
Most recent IF: 6.7; 2023 IF: 7.367 |
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| |
Call Number |
EMAT @ emat @c:irua:195235 |
Serial |
7260 |
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| Permanent link to this record |
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Author |
De Backer, A.; Bals, S.; Van Aert, S. |
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Title |
A decade of atom-counting in STEM: From the first results toward reliable 3D atomic models from a single projection |
Type |
A1 Journal article |
| |
Year |
2023 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
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| |
Volume |
|
Issue |
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Pages |
113702 |
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| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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| |
Abstract |
Quantitative structure determination is needed in order to study and understand nanomaterials at the atomic scale. Materials characterisation resulting in precise structural information is a crucial point to understand the structure–property relation of materials. Counting the number of atoms and retrieving the 3D atomic structure of nanoparticles plays an important role here. In this paper, an overview will be given of the atom-counting methodology and its applications over the past decade. The procedure to count the number of atoms will be discussed in detail and it will be shown how the performance of the method can be further improved. Furthermore, advances toward mixed element nanostructures, 3D atomic modelling based on the atom-counting results, and quantifying the nanoparticle dynamics will be highlighted. |
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Corporate Author |
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Place of Publication |
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Editor |
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Language |
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Wos |
000953765800001 |
Publication Date |
2023-02-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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| |
ISSN |
0304-3991 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.2 |
Times cited |
3 |
Open Access |
OpenAccess |
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Notes |
This work was supported by the European Research Council (Grant 770887 PICOMETRICS to S. Van Aert, Grant 815128 REALNANO to S. Bals, and Grant 823717 ESTEEM3). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through project fundings (G.0267.18N, G.0502.18N, G.0346.21N, and EOS 30489208) and a postdoctoral grant to A. De Backer. S. Van Aert acknowledges funding from the University of Antwerp Research fund (BOF) . The authors also thank the colleagues who have contributed to this work over the years, including T. Altantzis, E. Arslan Irmak, K.J. Batenburg, E. Bladt, A. De wael, R. Erni, C. Faes, B. Goris, L. Jones, L.M. Liz-Marzán, I. Lobato, G.T. Martinez, P.D. Nellist, M.D. Rosell, A. Rosenauer, K.H.W. van den Bos, A. Varambhia, and Z. Zhang.; esteem3reported; esteem3JRA |
Approved |
Most recent IF: 2.2; 2023 IF: 2.843 |
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Call Number |
EMAT @ emat @c:irua:195896 |
Serial |
7236 |
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| Permanent link to this record |
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Author |
Mary Joy, R.; Pobedinskas, P.; Bourgeois, E.; Chakraborty, T.; Görlitz, J.; Herrmann, D.; Noël, C.; Heupel, J.; Jannis, D.; Gauquelin, N.; D'Haen, J.; Verbeeck, J.; Popov, C.; Houssiau, L.; Becher, C.; Nesládek, M.; Haenen, K. |
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Title |
Germanium vacancy centre formation in CVD nanocrystalline diamond using a solid dopant source |
Type |
A1 Journal Article |
| |
Year |
2023 |
Publication |
Science talks |
Abbreviated Journal |
Science Talks |
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| |
Volume |
5 |
Issue |
|
Pages |
100157 |
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| |
Keywords |
A3 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
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Publication Date |
2023-02-09 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2772-5693 |
ISBN |
|
Additional Links |
UA library record |
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Impact Factor |
|
Times cited |
|
Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
EMAT @ emat @c:irua:196969 |
Serial |
8791 |
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| Permanent link to this record |
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Author |
Smeyers, R.; Milošević, M.V.; Covaci, L. |
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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 |
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| |
Volume |
15 |
Issue |
9 |
Pages |
4561-4569 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
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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. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000933052600001 |
Publication Date |
2023-02-07 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2040-3364; 2040-3372 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.7 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 6.7; 2023 IF: 7.367 |
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Call Number |
UA @ admin @ c:irua:195249 |
Serial |
7340 |
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| Permanent link to this record |
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Author |
Benedet, M.; Andrea Rizzi, G.; Gasparotto, A.; Gauquelin, N.; Orekhov, A.; Verbeeck, J.; Maccato, C.; Barreca, D. |
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Title |
Functionalization of graphitic carbon nitride systems by cobalt and cobalt-iron oxides boosts solar water oxidation performances |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
Applied surface science |
Abbreviated Journal |
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Volume |
618 |
Issue |
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Pages |
156652 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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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. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000950654300001 |
Publication Date |
2023-02-04 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0169-4332 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.7 |
Times cited |
11 |
Open Access |
OpenAccess |
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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 |
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Call Number |
EMAT @ emat @c:irua:196150 |
Serial |
7376 |
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Author |
Cui, W.; Lin, W.; Lu, W.; Liu, C.; Gao, Z.; Ma, H.; Zhao, W.; Van Tendeloo, G.; Zhao, W.; Zhang, Q.; Sang, X. |
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Title |
Direct observation of cation diffusion driven surface reconstruction at van der Waals gaps |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
Nature communications |
Abbreviated Journal |
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| |
Volume |
14 |
Issue |
1 |
Pages |
554-10 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Weak interlayer van der Waals (vdW) bonding has significant impact on the surface/interface structure, electronic properties, and transport properties of vdW layered materials. Unraveling the complex atomistic dynamics and structural evolution at vdW surfaces is therefore critical for the design and synthesis of the next-generation vdW layered materials. Here, we show that Ge/Bi cation diffusion along the vdW gap in layered GeBi2Te4 (GBT) can be directly observed using in situ heating scanning transmission electron microscopy (STEM). The cation concentration variation during diffusion was correlated with the local Te-6 octahedron distortion based on a quantitative analysis of the atomic column intensity and position in time-elapsed STEM images. The in-plane cation diffusion leads to out-of-plane surface etching through complex structural evolutions involving the formation and propagation of a non-centrosymmetric GeTe2 triple layer surface reconstruction on fresh vdW surfaces, and GBT subsurface reconstruction from a septuple layer to a quintuple layer. Our results provide atomistic insight into the cation diffusion and surface reconstruction in vdW layered materials. Weak interlayer van der Waals (vdW) bonding has significant impact on the structure and properties of vdW layered materials. Here authors use in-situ aberration-corrected ADF-STEM for an atomistic insight into the cation diffusion in the vdW gaps and the etching of vdW surfaces at high temperatures. |
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Corporate Author |
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Place of Publication |
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Language |
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Wos |
001076227200001 |
Publication Date |
2023-02-02 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2041-1723 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
|
Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:201342 |
Serial |
9021 |
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| Permanent link to this record |
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Author |
Bian, G.; Ageeva, O.; Roddatis, V.; Li, C.; Pennycook, T.J.; Habler, G.; Abart, R. |
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Title |
Crystal structure controls on oriented primary magnetite micro-inclusions in plagioclase From oceanic gabbro |
Type |
A1 Journal article |
| |
Year |
2023 |
Publication |
Journal of petrology |
Abbreviated Journal |
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| |
Volume |
64 |
Issue |
3 |
Pages |
egad008-18 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Oriented needle-, lath- and plate-shaped magnetite micro-inclusions in rock forming plagioclase from mafic intrusive rocks, were investigated using correlated optical microscopy and scanning transmission electron microscopy. The magnetite micro-inclusions were analysed on cuts parallel and perpendicular to the inclusion-elongation directions. The crystal structures of the two phases are in direct contact along the interfaces. The shape, shape orientation and crystallographic orientation relationships between the magnetite micro-inclusions and the plagioclase host appear to be controlled by the tendency of the system to optimise lattice match along the interfaces. The elongation direction of the inclusions ensures good match between prominent oxygen layers in the magnetite and plagioclase crystal structures across the interfaces bounding the inclusions parallel to their elongation direction. In cross-section, additional modes of lattice match, such as the commensurate impingement of magnetite and plagioclase lattice planes along the interfaces, the parallel alignment of the interfaces to low-index lattice planes of magnetite or plagioclase, or the parallel alignment to low index lattice planes of both phases are observed, which appear to control the selection of interface facets, as well as the shape and crystallographic orientation relationships between magnetite micro-inclusions and plagioclase host. The systematics of the inclusion cross-sectional shapes and crystallographic orientation relationships indicate recrystallisation of magnetite with potential implications for natural remanent magnetisation of magnetite-bearing plagioclase grains. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
001010636400007 |
Publication Date |
2023-01-28 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0022-3530 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
3.9 |
Times cited |
|
Open Access |
OpenAccess |
|
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Notes |
|
Approved |
Most recent IF: 3.9; 2023 IF: 3.28 |
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Call Number |
UA @ admin @ c:irua:195160 |
Serial |
7292 |
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| Permanent link to this record |
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Author |
Bhatia, H.; Martin, C.; Keshavarz, M.; Dovgaliuk, I.; Schrenker, N.J.; Ottesen, M.; Qiu, W.; Fron, E.; Bremholm, M.; Van de Vondel, J.; Bals, S.; Roeffaers, M.B.J.; Hofkens, J.; Debroye, E. |
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Title |
Deciphering the role of water in promoting the optoelectronic performance of surface-engineered lead halide perovskite nanocrystals |
Type |
A1 Journal article |
| |
Year |
2023 |
Publication |
ACS applied materials and interfaces |
Abbreviated Journal |
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| |
Volume |
15 |
Issue |
5 |
Pages |
7294-7307 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Lead halide perovskites are promising candidates for applicability is limited by their structural instability toward moisture. Although a deliberate addition of water to the precursor solution has recently been shown to improve the crystallinity and optical properties of perovskites, the corresponding thin films still do not exhibit a near-unity quantum yield. Herein, we report that the direct addition of a minute amount of water to post-treated substantially enhances the stability while achieving a 95% photoluminescence quantum yield in a NC thin film. We unveil the mechanism of how moisture assists in the formation of an additional NH4Br component. Alongside, we demonstrate the crucial role of moisture in assisting localized etching of the perovskite crystal, facilitating the partial incorporation of NH4+, which is key for improved performance under ambient conditions. Finally, as a proof-of-concept, the application of post-treated and watertreated perovskites is tested in LEDs, with the latter exhibiting a superior performance, offering opportunities toward commercial application in moisture-stable optoelectronics. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000931729400001 |
Publication Date |
2023-01-27 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1944-8244 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.5 |
Times cited |
3 |
Open Access |
Not_Open_Access |
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Notes |
H.B. would like to express her sincere gratitude to Dr. Peter Erk (formerly BASF SE, Germany) for very insightful discussions. The authors acknowledge financial support from the Research Foundation-Flanders (FWO grant numbers S002019N, 1514220N, G.0B39.15, G.0B49.15, G098319N, and ZW15_09-GOH6316) , the KU Leuven Research Fund (C14/19/079, iBOF-21-085 PERSIST, and STG/21/010) , the Flemish government through long-term structural funding Methusalem (CASAS2, Meth/15/04) , the Hercules Founda-tion (HER/11/14) , and the ERC through the Marie Curie ITN iSwitch Ph.D. fellowship to H.B. (grant number 642196) . C.M. acknowledges the financial support from grants PID2021-128761OA-C22 funded by MCIN/AEI/10.13039/501100011033 by the ?European Union? and SBPLY/21/180501/000127 funded by JCCM and by the EU through Fondo Europeo de Desarollo Regional? (FEDER) . Martin Bremholm and Martin Ottesen acknowledge funding from the Danish Council for Independent Research, Natural Sciences, under the Sapere Aude program (grant no. 7027-00077B) and VILLUM FONDEN through the Centre of Excellence for Dirac Materials (grant no. 11744) . Affiliation with the Center for Integrated Materials Research (iMAT) at Aarhus University is gratefully acknowledged.-N.J.S. acknowledges financial support from the research foundation Flanders (FWO) through a postdoctoral fellowship (FWO grant no. 1238622N) . S.B. acknowledges financial support from the European Commission by the ERC Consolidator grant REALNANO (no. 815128) . |
Approved |
Most recent IF: 9.5; 2023 IF: 7.504 |
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| |
Call Number |
UA @ admin @ c:irua:195375 |
Serial |
7293 |
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| Permanent link to this record |
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Author |
Marchetti, A.; Gori, A.; Ferretti, A.M.; Esteban, D.A.; Bals, S.; Pigliacelli, C.; Metrangolo, P. |
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Title |
Templated Out‐of‐Equilibrium Self‐Assembly of Branched Au Nanoshells |
Type |
A1 Journal article |
| |
Year |
2023 |
Publication |
Small |
Abbreviated Journal |
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Volume |
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Issue |
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Pages |
2206712 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Out-of-equilibrium self-assembly of metal nanoparticles (NPs) has been devised using different types of strategies and fuels, but the achievement of finite 3D structures with a controlled morphology through this assembly mode is still rare. Here we used a spherical peptide-gold superstructure (PAuSS) as a template to control the out-of-equilibrium self-assembly of Au NPs, obtaining a transient 3D branched Au-nanoshell (BAuNS) stabilized by sodium dodecyl sulphate (SDS). The BAuNS dismantled upon concentration gradient equilibration over time in the solution, leading to NPs disassembly. Notably, BAuNS assembly and disassembly favoured temporary interparticle plasmonic coupling, leading to a remarkable oscillation of their optical properties. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000914725800001 |
Publication Date |
2023-01-17 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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| |
ISSN |
1613-6810 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
13.3 |
Times cited |
1 |
Open Access |
OpenAccess |
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| |
Notes |
European Research Council, ERC‐2017‐PoC MINIRES 789815 ERC‐2012‐StG_20111012 FOLDHALO 307108 815128 ; |
Approved |
Most recent IF: 13.3; 2023 IF: 8.643 |
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Call Number |
EMAT @ emat @c:irua:194299 |
Serial |
7247 |
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| Permanent link to this record |
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Author |
Vijayakumar, J.; Savchenko, T.M.; Bracher, D.M.; Lumbeeck, G.; Béché, A.; Verbeeck, J.; Vajda, Š.; Nolting, F.; Vaz, Ca.f.; Kleibert, A. |
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Title |
Absence of a pressure gap and atomistic mechanism of the oxidation of pure Co nanoparticles |
Type |
A1 Journal Article |
| |
Year |
2023 |
Publication |
Nature communications |
Abbreviated Journal |
Nat Commun |
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| |
Volume |
14 |
Issue |
1 |
Pages |
174 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Understanding chemical reactivity and magnetism of 3<italic>d</italic>transition metal nanoparticles is of fundamental interest for applications in fields ranging from spintronics to catalysis. Here, we present an atomistic picture of the early stage of the oxidation mechanism and its impact on the magnetism of Co nanoparticles. Our experiments reveal a two-step process characterized by (i) the initial formation of small CoO crystallites across the nanoparticle surface, until their coalescence leads to structural completion of the oxide shell passivating the metallic core; (ii) progressive conversion of the CoO shell to Co<sub>3</sub>O<sub>4</sub>and void formation due to the nanoscale Kirkendall effect. The Co nanoparticles remain highly reactive toward oxygen during phase (i), demonstrating the absence of a pressure gap whereby a low reactivity at low pressures is postulated. Our results provide an important benchmark for the development of theoretical models for the chemical reactivity in catalysis and magnetism during metal oxidation at the nanoscale. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000955726400021 |
Publication Date |
2023-01-12 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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| |
ISSN |
2041-1723 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
16.6 |
Times cited |
1 |
Open Access |
OpenAccess |
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| |
Notes |
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, 200021160186 2002153540 ; EC | Horizon 2020 Framework Programme, 810310 823717 ; University of Basel | Swiss Nanoscience Institute, P1502 ; This work is funded by Swiss National Foundation (SNF) (Grants. No 200021160186 and 2002153540) and the Swiss Nanoscience Institut (SNI) (Grant No. SNI P1502). S.V. acknowledges support from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 810310, which corresponds to the J. Heyrovsky Chair project (“ERA Chair at J. Heyrovský Institute of Physical Chemistry AS CR – The institutional approach towards ERA”). The funders had no role in the preparation of the article. Part of this work was performed at the Surface/Interface: Microscopy (SIM) beamline of the Swiss Light Source (SLS), Paul Scherrer Institut, Villigen, Switzerland. We kindly acknowledge Anja Weber and Elisabeth Müller from PSI for their help in fabricating the sample markers. A.B. and J. Verbeeck received funding from the European Union’s Horizon 2020 Research Infrastructure – Integrating Activities for Advanced Communities under grant agreement No. 823717 – ESTEEM3 reported |
Approved |
Most recent IF: 16.6; 2023 IF: 12.124 |
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| |
Call Number |
EMAT @ emat @c:irua:196738 |
Serial |
8804 |
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| Permanent link to this record |
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Author |
Friedrich, T.; Yu, C.-P.; Verbeeck, J.; Van Aert, S. |
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Title |
Phase object reconstruction for 4D-STEM using deep learning |
Type |
A1 Journal article |
| |
Year |
2023 |
Publication |
Microscopy and microanalysis |
Abbreviated Journal |
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|
| |
Volume |
29 |
Issue |
1 |
Pages |
395-407 |
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| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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| |
Abstract |
In this study, we explore the possibility to use deep learning for the reconstruction of phase images from 4D scanning transmission electron microscopy (4D-STEM) data. The process can be divided into two main steps. First, the complex electron wave function is recovered for a convergent beam electron diffraction pattern (CBED) using a convolutional neural network (CNN). Subsequently, a corresponding patch of the phase object is recovered using the phase object approximation. Repeating this for each scan position in a 4D-STEM dataset and combining the patches by complex summation yields the full-phase object. Each patch is recovered from a kernel of 3x3 adjacent CBEDs only, which eliminates common, large memory requirements and enables live processing during an experiment. The machine learning pipeline, data generation, and the reconstruction algorithm are presented. We demonstrate that the CNN can retrieve phase information beyond the aperture angle, enabling super-resolution imaging. The image contrast formation is evaluated showing a dependence on the thickness and atomic column type. Columns containing light and heavy elements can be imaged simultaneously and are distinguishable. The combination of super-resolution, good noise robustness, and intuitive image contrast characteristics makes the approach unique among live imaging methods in 4D-STEM. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
001033590800038 |
Publication Date |
2023-01-12 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
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| |
ISSN |
1431-9276 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
2.8 |
Times cited |
1 |
Open Access |
OpenAccess |
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| |
Notes |
We acknowledge funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement no. 770887 PICOMETRICS) and funding from the European Union's Horizon 2020 research and innovation program under grant agreement No. 823717 ESTEEM3. J.V. and S.V.A acknowledge funding from the University of Antwerp through a TOP BOF project. The direct electron detector (Merlin, Medipix3, Quantum Detectors) was funded by the Hercules fund from the Flemish Government. This work was supported by the FWO and FNRS within the 2Dto3D project of the EOS program (grant number 30489208). |
Approved |
Most recent IF: 2.8; 2023 IF: 1.891 |
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| |
Call Number |
UA @ admin @ c:irua:198221 |
Serial |
8912 |
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| Permanent link to this record |
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Author |
Chowdhury, M.S.; Rösch, E.L.; Esteban, D.A.; Janssen, K.-J.; Wolgast, F.; Ludwig, F.; Schilling, M.; Bals, S.; Viereck, T.; Lak, A. |
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Title |
Decoupling the Characteristics of Magnetic Nanoparticles for Ultrahigh Sensitivity |
Type |
A1 Journal article |
| |
Year |
2023 |
Publication |
Nano letters |
Abbreviated Journal |
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| |
Volume |
23 |
Issue |
1 |
Pages |
58-65 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Immunoassays exploiting magnetization dynamics of magnetic nanoparticles are highly promising for mix-and-measure, quantitative, and point-of-care diagnostics. However, how single-core magnetic nanoparticles can be employed to reduce particle concentration and concomitantly maximize assay sensitivity is not fully understood. Here, we design monodisperse Néel and Brownian relaxing magnetic nanocubes (MNCs) of different sizes and compositions. We provide insights into how to decouple physical properties of these MNCs to achieve ultrahigh sensitivity. We find that tri-component-based Zn0.06 Co0.80Fe2.14 O4 particles, with out-of-phase to initial magnetic susceptibility χ /χ ratio of 0.47 out of 0.50 for magnetically blocked ideal particles, show the ultrahigh magnetic sensitivity by providing rich magnetic particle spectroscopy (MPS) harmonics spectrum despite bearing lower saturation magnetization than di-component Zn0.1Fe2.9O4 having high saturation magnetization. The Zn0.06Co0.80Fe2.14O4 MNCs, coated with catechol-based polyethylene glycol ligands, measured by our benchtop MPS show three orders of magnitude better particle LOD than that of commercial nanoparticles of comparable size. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000907816300001 |
Publication Date |
2023-01-11 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1530-6984 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
10.8 |
Times cited |
1 |
Open Access |
OpenAccess |
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Notes |
Deutsche Forschungsgemeinschaft, DFG RTG 1952 ; Joachim Herz Stiftung; H2020 Research Infrastructures, 823717 ; |
Approved |
Most recent IF: 10.8; 2023 IF: 12.712 |
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Call Number |
EMAT @ emat @c:irua:193406 |
Serial |
7248 |
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| Permanent link to this record |
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Author |
Posokhova, S.M.M.; Morozov, V.A.; Deyneko, D.V.V.; Redkin, B.S.S.; Spassky, D.A.A.; Nagirnyi, V.; Belik, A.A.A.; Hadermann, J.; Pavlova, E.T.T.; Lazoryak, B.I.I. |
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Title |
K₅Eu(MoO₄)₄ red phosphor for solid state lighting applications, prepared by different techniques |
Type |
A1 Journal article |
| |
Year |
2023 |
Publication |
CrystEngComm |
Abbreviated Journal |
Crystengcomm |
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| |
Volume |
25 |
Issue |
5 |
Pages |
835-847 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The influence of preparation techniques on the structure and luminescent properties of K5Eu(MoO4)(4) (KEMO) was investigated. KEMO phosphors were synthesized by three different techniques: solid state and sol-gel (sg) methods as well as the Czochralski (CZ) crystal growth technique. Laboratory powder X-ray diffraction (PXRD) studies revealed that all KEMO samples had a structure analogous to that of other high temperature alpha-K5R(MoO4)(4) palmierite-type phases (space group (SG) R3m). Contrary to laboratory PXRD data, electron diffraction revealed that the KEMO crystal grown by the CZ technique had a (3 + 1)D incommensurately modulated structure (super space group (SSG) C2/m(0 beta 0)00) with the modulation vector q = 0.689b*. A detailed analysis of electron diffraction patterns has shown formation of three twin domains rotated along the c axis of the R-subcell at 60 degrees with respect to each other. Synchrotron XRD patterns showed additional ultra-wide reflexes in addition to reflections of the R-subcell of the palmierite. However, the insufficient number of reflections, their low intensity and large width in the synchrotron X-ray diffraction patterns made it impossible to refine the structure as incommensurately modulated C2/m(0 beta 0)00. An average structure was refined in the C2/m space group with random distribution of K1 and Eu1 in [M1A(2)O(8)]-layers of the palmierite-type structure. The dependence of luminescent properties on utilized synthesis techniques was studied. The emission spectra of all samples exhibit intense red emission originating from the D-5(0) -> F-7(2) Eu3+ transition. The integrated intensity of the emission from the Eu3+ 5D0 term was found to be the highest in the crystal grown by the CZ technique. The quantum yield measured for KEMO crystals demonstrates a very high value of 66.5%. This fact confirms that KEMO crystals are exceptionally attractive for applications as a near-UV converting red phosphor for LEDs. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000912021300001 |
Publication Date |
2023-01-06 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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| |
ISSN |
1466-8033 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.1 |
Times cited |
|
Open Access |
Not_Open_Access |
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Notes |
|
Approved |
Most recent IF: 3.1; 2023 IF: 3.474 |
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Call Number |
UA @ admin @ c:irua:194320 |
Serial |
7317 |
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| Permanent link to this record |
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Author |
Mulder, J.T.; Meijer, M.S.; van Blaaderen, J.J.; du Fosse, I.; Jenkinson, K.; Bals, S.; Manna, L.; Houtepen, A.J. |
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Title |
Understanding and preventing photoluminescence quenching to achieve unity photoluminescence quantum yield in Yb:YLF nanocrystals |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
ACS applied materials and interfaces |
Abbreviated Journal |
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Volume |
15 |
Issue |
2 |
Pages |
3274-3286 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Ytterbium-doped LiYF4 (Yb:YLF) is a commonly used material for laser applications, as a photon upconversion medium, and for optical refrigeration. As nanocrystals (NCs), the material is also of interest for biological and physical applications. Unfortunately, as with most phosphors, with the reduction in size comes a large reduction of the photoluminescence quantum yield (PLQY), which is typically associated with an increase in surface-related PL quenching. Here, we report the synthesis of bipyramidal Yb:YLF NCs with a short axis of similar to 60 nm. We systematically study and remove all sources of PL quenching in these NCs. By chemically removing all traces of water from the reaction mixture, we obtain NCs that exhibit a near-unity PLQY for an Yb3+ concentration below 20%. At higher Yb3+ concentrations, efficient concentration quenching occurs. The surface PL quenching is mitigated by growing an undoped YLF shell around the NC core, resulting in near-unity PLQY values even for fully Yb3+-based LiYbF4 cores. This unambiguously shows that the only remaining quenching sites in core-only Yb:YLF NCs reside on the surface and that concentration quenching is due to energy transfer to the surface. Monte Carlo simulations can reproduce the concentration dependence of the PLQY. Surprisingly, Fo''rster resonance energy transfer does not give satisfactory agreement with the experimental data, whereas nearest-neighbor energy transfer does. This work demonstrates that Yb3+-based nanophosphors can be synthesized with a quality close to that of bulk single crystals. The high Yb3+ concentration in the LiYbF4/LiYF4 core/shell nanocrystals increases the weak Yb3+ absorption, making these materials highly promising for fundamental studies and increasing their effectiveness in bioapplications and optical refrigeration. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000912997300001 |
Publication Date |
2023-01-06 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1944-8244 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.5 |
Times cited |
3 |
Open Access |
OpenAccess |
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Notes |
This project has received funding from the European Union's Horizon 2020 research and innovation program under Grant Agreement No. 766900 (Testing the Large-Scale Limit of Quantum Mechanics). A.J.H. and I.d.F. further acknowledge the European Research Council Horizon 2020 ERC Grant Agreement No. 678004 (Doping on Demand) for financial support. The authors thank Freddy Rabouw and Andries Meijerink (Utrecht University) for very fruitful discussions and extremely useful advice. The author s thank Jos Thieme for his help with the laser setups used . The authors furthermore thank Niranjan Saikumar for proofreading the manuscript. |
Approved |
Most recent IF: 9.5; 2023 IF: 7.504 |
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Call Number |
UA @ admin @ c:irua:194317 |
Serial |
7348 |
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Author |
Zhang, Z.; Lobato, I.; De Backer, A.; Van Aert, S.; Nellist, P. |
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Title |
Fast generation of calculated ADF-EDX scattering cross-sections under channelling conditions |
Type |
A1 Journal article |
| |
Year |
2023 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
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| |
Volume |
246 |
Issue |
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Pages |
113671 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Advanced materials often consist of multiple elements which are arranged in a complicated structure. Quantitative scanning transmission electron microscopy is useful to determine the composition and thickness of nanostructures at the atomic scale. However, significant difficulties remain to quantify mixed columns by comparing the resulting atomic resolution images and spectroscopy data with multislice simulations where dynamic scattering needs to be taken into account. The combination of the computationally intensive nature of these simulations and the enormous amount of possible mixed column configurations for a given composition indeed severely hamper the quantification process. To overcome these challenges, we here report the development of an incoherent non-linear method for the fast prediction of ADF-EDX scattering cross-sections of mixed columns under channelling conditions. We first explain the origin of the ADF and EDX incoherence from scattering physics suggesting a linear dependence between those two signals in the case of a high-angle ADF detector. Taking EDX as a perfect incoherent reference mode, we quantitatively examine the ADF longitudinal incoherence under different microscope conditions using multislice simulations. Based on incoherent imaging, the atomic lensing model previously developed for ADF is now expanded to EDX, which yields ADF-EDX scattering cross-section predictions in good agreement with multislice simulations for mixed columns in a core–shell nanoparticle and a high entropy alloy. The fast and accurate prediction of ADF-EDX scattering cross-sections opens up new opportunities to explore the wide range of ordering possibilities of heterogeneous materials with multiple elements. |
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Address |
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Corporate Author |
Zezhong Zhang |
Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000995063900001 |
Publication Date |
2022-12-28 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0304-3991 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.2 |
Times cited |
|
Open Access |
OpenAccess |
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Notes |
European Research Council 770887 PICOMETRICS; Fonds Wetenschappelijk Onderzoek No.G.0502.18N; Horizon 2020, 770887 ; Horizon 2020 Framework Programme; European Research Council, 823717 ESTEEM3 ; esteem3reported; esteem3JRa |
Approved |
Most recent IF: 2.2; 2023 IF: 2.843 |
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Call Number |
EMAT @ emat @c:irua:195890 |
Serial |
7251 |
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| Permanent link to this record |
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Author |
Skorikov, A.; Batenburg, K.J.; Bals, S. |
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Title |
Analysis of 3D elemental distribution in nanomaterials : towards higher throughput and dose efficiency |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
Journal of microscopy |
Abbreviated Journal |
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Volume |
289 |
Issue |
3 |
Pages |
157-163 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Many advanced nanomaterials rely on carefully designed morphology and elemental distribution to achieve their functionalities. Among the few experimental techniques that can directly visualise the 3D elemental distribution on the nanoscale are approaches based on electron tomography in combination with energy-dispersive X-ray spectroscopy (EDXS) and electron energy loss spectroscopy (EELS). Unfortunately, these highly informative methods are severely limited by the fundamentally low signal-to-noise ratio, which makes long experimental times and high electron irradiation doses necessary to obtain reliable 3D reconstructions. Addressing these limitations has been the major research question for the development of these techniques in recent years. This short review outlines the latest progress on the methods to reduce experimental time and electron irradiation dose requirements for 3D elemental distribution analysis and gives an outlook on the development of this field in the near future. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000910532600001 |
Publication Date |
2022-12-26 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0022-2720 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2 |
Times cited |
2 |
Open Access |
OpenAccess |
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Notes |
ERC Consolidator Grant, Grant/Award Number: 815128 |
Approved |
Most recent IF: 2; 2023 IF: 1.692 |
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Call Number |
UA @ admin @ c:irua:193428 |
Serial |
7281 |
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Author |
Panzic, I.; Mandic, V.; Mangalam, J.; Rath, T.; Radovanovic-Peric, F.; Gaboardi, M.; De Coen, B.; Bals, S.; Schrenker, N. |
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Title |
In-situ structural degradation study of quadruple-cation perovskite solar cells with nanostructured charge transfer layer |
Type |
A1 Journal article |
| |
Year |
2023 |
Publication |
Ceramics international |
Abbreviated Journal |
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| |
Volume |
49 |
Issue |
14b |
Pages |
24475-24486 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
We investigated the structural stability of perovskite solar cells (PSCs) in n-i-p configuration comprising a rubidium-caesium-methylammonium-formamidinium (Rb-Cs-MA-FA) lead iodide/bromide perovskite absorber, interfaced with nanostructured ZnO-nanorod (NR) or mesostructured (MS) TiO2 electron transfer layers (ETL). An in-situ setup was established comprising synchrotron grazing incidence diffraction (GID) and Raman spectroscopy as a function of temperature under ambient and isothermal conditions; measurements of current-voltage (IV) characteristics and electron microscopic investigations were conducted discretely.The aging of the solar cells was performed at ambient conditions or at elevated temperatures directly in the in -situ measurement setup. The diffraction depth profiling results point to different degradation rates for different ETLs; moreover, electron microscopy and atomic force microscopy, as well as energy dispersive spectroscopy clarified surface conditions in terms of the extent of the degradation. Scanning transmission electron microscopy of lamellas, derived by dual beam microscopy, revealed that the origin of the degradation lay in the ETL/ absorber interface. For the case of the nanostructured zincite, the perovskite absorber contained many voids, leading to the conclusion that the investigated quadruple perovskite absorber showed limited compatibility with ZnO NR ETL due to a higher number of defects. Morphological defects promoted the absorber degradation and nullified the advantages initially achieved by nanostructuring. The exchange of the ZnO NR ETL with MS TiO2 improved the stability parameters of the absorber layer. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
001021057200001 |
Publication Date |
2022-12-25 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0272-8842; 1873-3956 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
5.2 |
Times cited |
|
Open Access |
OpenAccess |
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Notes |
This work has been funded by the projects PZS-2019-02-1555 PV-WALL in Research Cooperability Program of the Croatian Science Foundation funded by the European Union from the European Social Fund under the Operational Programme Efficient Human Resources 2014-2020 (perovskite solar cells) , UIP-2019-04-2367 SLIPPERY SLOPE of the Croatian Science Foundation (nanostructured titania and zincite constituents) , KK.01.2.1.02.0316 “ The development of the technical solution for energy saving using VIS -transparent or semi-transparent and IR-reflective thin-films” by the European Regional Development Fund (ERDF) (characterisation of thin-films) , 20190571 and 20190516 at Elettra Synchrotron, ICM-2019-13220 in Ernst Mach program of the OeAD-GmbH, and E210900588 in the EUSMI program. The group of prof Gregor Trimmel of the ICTM, NAWI Graz, the beam- line scientists of the MCX beamline of the Elettra synchrotron, and FIB- STEM researchers of the Faculty of Science, University of Antwerp, are gratefully acknowledged for collaboration and instrument access. The financial sustenance of the University of Zagreb is gratefully acknowledged. |
Approved |
Most recent IF: 5.2; 2023 IF: 2.986 |
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Call Number |
UA @ admin @ c:irua:197806 |
Serial |
8885 |
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Author |
Morsdorf, L.; Kashiwar, A.; Kübel, C.; Tasan, C.C. |
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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 |
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Volume |
862 |
Issue |
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Pages |
144369-21 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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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. |
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Place of Publication |
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Wos |
000905165700001 |
Publication Date |
2022-12-07 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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| |
ISSN |
0921-5093 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
6.4 |
Times cited |
|
Open Access |
Not_Open_Access |
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Notes |
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Approved |
Most recent IF: 6.4; 2023 IF: 3.094 |
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Call Number |
UA @ admin @ c:irua:192279 |
Serial |
7285 |
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| Permanent link to this record |
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Author |
Vladimirova, N.V.; Frolov, A.S.; Sanchez-Barriga, J.; Clark, O.J.; Matsui, F.; Usachov, D.Y.; Muntwiler, M.; Callaert, C.; Hadermann, J.; Neudachina, V.S.; Tamm, M.E.; Yashina, L.V. |
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Title |
Occupancy of lattice positions probed by X-ray photoelectron diffraction : a case study of tetradymite topological insulators |
Type |
A1 Journal article |
| |
Year |
2023 |
Publication |
Surfaces and interfaces |
Abbreviated Journal |
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| |
Volume |
36 |
Issue |
|
Pages |
102516-10 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Occupancy of different structural positions in a crystal lattice often seems to play a key role in material prop-erties. Several experimental techniques have been developed to uncover this issue, all of them being mostly bulk sensitive. However, many materials including topological insulators (TIs), which are among the most intriguing modern materials, are intended to be used in devices as thin films, for which the sublattice occupancy may differ from the bulk. One of the possible approaches to occupancy analysis is X-ray Photoelectron Diffraction (XPD), a structural method in surface science with chemical sensitivity. We applied this method in a case study of Sb2(Te1-xSex)3 mixed crystals, which belong to prototypical TIs. We used high-angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) as a reference method to verify our analysis. We revealed that the XPD data for vacuum cleaved bulk crystals are in excellent agreement with the reference ones. Also, we demonstrate that the anion occupancy near a naturally formed surface can be rather different from that of the bulk. The present results are relevant for a wide range of compositions where the system remains a topological phase, as we ultimately show by probing the transiently occupied topological surface state above the Fermi level by ultrafast photoemission. |
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Wos |
000901694900001 |
Publication Date |
2022-11-28 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2468-0230 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
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Impact Factor |
6.2 |
Times cited |
|
Open Access |
OpenAccess |
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| |
Notes |
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Approved |
Most recent IF: 6.2; 2023 IF: NA |
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Call Number |
UA @ admin @ c:irua:193502 |
Serial |
7327 |
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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. |
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Title |
Directly revealing the structure-property correlation in Na+-doped cathode materials |
Type |
A1 Journal article |
| |
Year |
2023 |
Publication |
Applied surface science |
Abbreviated Journal |
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| |
Volume |
612 |
Issue |
|
Pages |
155810-10 |
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| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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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. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000892940300001 |
Publication Date |
2022-11-23 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0169-4332 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6.7 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 6.7; 2023 IF: 3.387 |
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Call Number |
UA @ admin @ c:irua:192758 |
Serial |
7296 |
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| Permanent link to this record |
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Author |
Dinger, J.; Friedrich, T.; Reimann, T.; Toepfer, J. |
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Title |
NiMn₂O₄ revisited : temperature-dependent cation distribution from in situ neutron diffraction and thermopower studies |
Type |
A1 Journal article |
| |
Year |
2023 |
Publication |
Journal of the American Ceramic Society |
Abbreviated Journal |
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Volume |
106 |
Issue |
3 |
Pages |
1834-1847 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The cation distribution of the negative temperature coefficient (NTC) thermistor spinel NiMn2O4 was studied in the temperature range from 55 to 900 degrees C, using a combined in situ neutron diffraction and thermopower study. Rietveld refinements of in situ neutron diffraction data reveal a temperature dependence of the degree of inversion with an inversion parameter of 0.70(1) at 900 degrees C and 0.87(1) at 55 degrees C. Thermopower measurements were evaluated using a modified Heikes formula, and the [Mn4+]/[Mn3+] ratio on octahedral sites of the spinel structure was calculated considering spin and orbital degeneracy. The inversion degree and disproportionation parameter, determined independently as function of temperature, were used to calculate the cation distribution of NiMn2O4 in the whole temperature range. At high temperature, within the stability range of the spinel, the cation distribution is characterized by a moderate degree of inversion with a concentration of NiB2+${\mathrm{Ni}}\mathrm{B}< |
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Corporate Author |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000880360600001 |
Publication Date |
2022-10-21 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0002-7820 |
ISBN |
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Additional Links |
UA library record; WoS full record |
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Impact Factor |
3.9 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 3.9; 2023 IF: 2.841 |
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Call Number |
UA @ admin @ c:irua:192087 |
Serial |
7326 |
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| Permanent link to this record |
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Author |
Yang, T.; Kong, Y.; Du, Y.; Li, K.; Schryvers, D. |
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Title |
Discovery of core-shell quasicrystalline particles |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
Scripta materialia |
Abbreviated Journal |
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Volume |
222 |
Issue |
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Pages |
115040-115046 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Submicron-sized quasicrystalline particles were obtained in an Al-Zn-Mg-Cu alloy produced by traditional melting. These particles consist of an Al-Fe-Ni core and a Mg-Cu-Zn shell and were found to be stable and embedded randomly in the Al matrix. The diffraction patterns of these core-shell particles reveal a decagonal core and an icosahedral shell with, respectively, ten- and five-fold axes aligned. High resolution scanning transmission electron microscopy of the Mg-Cu-Zn shell confirms the five-fold symmetry atomic arrangement and the icosahedral structure. It can therefore be concluded that Fe and Ni impurities play an important role in mediating the formation of such an unusual ternary core-shell quasicrystalline particle. These findings provide some novel insights in the formation of quasicrystals in traditional industrial Al alloys. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000864491400005 |
Publication Date |
2022-09-11 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1359-6462 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
6 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 6; 2023 IF: 3.747 |
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Call Number |
UA @ admin @ c:irua:191489 |
Serial |
7144 |
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Author |
Liu, J.; Wang, C.; Yu, W.; Zhao, H.; Hu, Z.-Y.; Liu, F.; Hasan, T.; Li, Y.; Van Tendeloo, G.; Li, C.; Su, B.-L. |
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Title |
Bioinspired noncyclic transfer pathway electron donors for unprecedented hydrogen production |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
CCS chemistry |
Abbreviated Journal |
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Volume |
5 |
Issue |
6 |
Pages |
1470-1482 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Electron donors are widely exploited in visible-light photocatalytic hydrogen production. As a typical electron donor pair and often the first choice for hydrogen production, the sodium sulfide-sodium sulfite pair has been extensively used. However, the resultant thiosulfate ions consume the photogenerated electrons to form an undesirable pseudocyclic electron transfer pathway during the photocatalytic process, strongly limiting the solar energy conversion efficiency. Here, we report novel and bioinspired electron donor pairs offering a noncyclic electron transfer pathway that provides more electrons without the consumption of the photogenerated electrons. Compared to the state-of-the-art electron donor pair Na2S-Na2SO3, these novel Na2S-NaH2PO2 and Na2S-NaNO2 electron donor pairs enable an unprecedented enhancement of up to 370% and 140% for average photocatalytic H-2 production over commercial CdS nanoparticles, and they are versatile for a large series of photocatalysts for visible-light water splitting. The discovery of these novel electron donor pairs can lead to a revolution in photocatalysis and is of great significance for industrial visible-light-driven H-2 production. [GRAPHICS] . |
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Wos |
001037091900008 |
Publication Date |
2022-06-30 |
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Series Editor |
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Edition |
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ISSN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:198409 |
Serial |
8837 |
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Author |
Zhang, Z.; Lobato, I.; Brown, H.; Jannis, D.; Verbeeck, J.; Van Aert, S.; Nellist, P. |
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Title |
Generalised oscillator strength for core-shell electron excitation by fast electrons based on Dirac solutions |
Type |
Dataset |
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Year |
2023 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
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Keywords |
Dataset; Electron microscopy for materials research (EMAT) |
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Abstract |
Inelastic excitation as exploited in Electron Energy Loss Spectroscopy (EELS) contains a rich source of information that is revealed in the scattering process. To accurately quantify core-loss EELS, it is common practice to fit the observed spectrum with scattering cross-sections calculated using experimental parameters and a Generalized Oscillator Strength (GOS) database [1]. The GOS is computed using Fermi’s Golden Rule and orbitals of bound and excited states. Previously, the GOS was based on Hartree-Fock solutions [2], but more recently Density Functional Theory (DFT) has been used [3]. In this work, we have chosen to use the Dirac equation to incorporate relativistic effects and have performed calculations using Flexible Atomic Code (FAC) [4]. This repository contains a tabulated GOS database based on Dirac solutions for computing double differential cross-sections under experimental conditions. We hope the Dirac-based GOS database can benefit the EELS community for both academic use and industry integration. Database Details: – Covers all elements (Z: 1-108) and all edges – Large energy range: 0.01 – 4000 eV – Large momentum range: 0.05 -50 Å-1 – Fine log sampling: 128 points for energy and 256 points for momentum – Data format: GOSH [3] Calculation Details: – Single atoms only; solid-state effects are not considered – Unoccupied states before continuum states of ionization are not considered; no fine structure – Plane Wave Born Approximation – Frozen Core Approximation is employed; electrostatic potential remains unchanged for orthogonal states when – core-shell electron is excited – Self-consistent Dirac–Fock–Slater iteration is used for Dirac calculations; Local Density Approximation is assumed for electron exchange interactions; continuum states are normalized against asymptotic form at large distances – Both large and small component contributions of Dirac solutions are included in GOS – Final state contributions are included until the contribution of the previous three states falls below 0.1%. A convergence log is provided for reference. Version 1.1 release note: – Update to be consistent with GOSH data format [3], all the edges are now within a single hdf5 file. A notable change in particular, the sampling in momentum is in 1/m, instead of previously in 1/Å. Great thanks to Gulio Guzzinati for his suggestions and sending conversion script. Version 1.2 release note: – Add “File Type / File version” information [1] Verbeeck, J., and S. Van Aert. Ultramicroscopy 101.2-4 (2004): 207-224. [2] Leapman, R. D., P. Rez, and D. F. Mayers. The Journal of Chemical Physics 72.2 (1980): 1232-1243. [3] Segger, L, Guzzinati, G, & Kohl, H. Zenodo (2023). doi:10.5281/zenodo.7645765 [4] Gu, M. F. Canadian Journal of Physics 86(5) (2008): 675-689. |
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UA library record |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:203392 |
Serial |
9042 |
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Author |
Yu, C.-P. |
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Title |
Novel imaging methods of transmission electron microscopy based on electron beam scattering and modulation |
Type |
Doctoral thesis |
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Year |
2023 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
x, 154 p. |
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Keywords |
Doctoral thesis; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Transmission electron microscopy (TEM) is a technique that uses an electron beam to analyze materials. This analysis is based on the interaction between the electron beam and the sample, such as photon emission and electron diffraction pattern, to name a few. Sample damage, however, also occurs when such interaction alters the structure of the sample. To ensure information from the undamaged material can be acquired, the electron expense to probe the material is thus limited. In this work, we propose efficient methods for acquiring and processing the information originating from the electron-sample interaction so that the study of the material and the conducting of the TEM experiment can be less hindered by the limited dose usage. In the first part of the work, the relationship between the scattering of the electron and the local physical property of the sample is studied. Based on this relationship, two reconstruction schemes are proposed capable of producing high-resolution images at low-dose conditions. Besides, the proposed reconstructions are not restricted to complete datasets but instead work on pieces of data, therefore allowing live feedback during data acquisition. Such feature of the methods allows the whole TEM experiment to be carried out under low dose conditions and thus further reduces possible beam damage on the studied material. In the second part of the work, we discuss our approach to modulating the electron beam and its benefits. An electrostatic device that can alter the wavefront of the passing electron wave is introduced and characterized. The beam-modulation ability is demonstrated by creating orthogonal beam sets, and applications that exploit the adaptability of the wave modulator are demonstrated with both simulation and experiments. |
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ISBN |
987-90-5728-534-7 |
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UA library record |
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no |
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Call Number |
UA @ admin @ c:irua:200885 |
Serial |
9064 |
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Author |
Yang, T. |
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Title |
Characterization of Laves phase structural evolution and regulation of its precipitation behavior in Al-Zn-Mg based alloys |
Type |
Doctoral thesis |
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Year |
2023 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
ii, 106 p. |
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Keywords |
Doctoral thesis; Electron microscopy for materials research (EMAT) |
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Abstract |
Al-Zn-Mg-based high strength alloys are widely used in aerospace applications due to their low density and excellent mechanical properties. A systematic study of the structural evolution of the nano-precipitation phase and its growth mechanism is an important guide for the design of new high-strength alloys. In this work, the Laves structure precipitates in Al-Zn-Mg(-Cu/Y) alloy was systematically characterized. Based on the structure evolution, the structure of submicron Laves particles and quasicrystalline particles in the alloy at microscale, as well as the regulation of the precipitation behavior after adding Y at nanoscale were further investigated. The main innovative results are summarized as follows: (1) Investigation on coexistence of defect structures in Laves structural nanoprecipitates. Three types of Laves structures can coexist within the η-MgZn2 precipitates: C14, C15 and C36, and the Laves structure transition sequence of C14→C36→C15 in this system was determined. Meanwhile, it was found that there are diverse defect structures in the MgZn2 phase, including stacking faults, planar defects and five-fold domain structures, which have significant effects on relieving the internal stress/strain of the precipitates. (2) Investigation on multiple phase transition of Laves structural nanoprecipitates from C14 to C36 and from C14 to quasicrystal clusters. It is found that C14 precipitates can be completely transformed into the C36 precipitates. And it is also found that the C14 Laves phase structure can also transform into quasicrystalline clusters. These investigations on various phase transition mechanisms among Laves phases provide theoretical support for the microstructural characterization of materials containing multi-scale Laves phases. (3) Characterization of Laves and quasicrystal structural particles in submicron scale. Submicron-scale quasicrystal particles were obtained in conventional casting Al-Zn-Mg-Cu alloys for the first time. Industrial impurity elements Fe and Ni can induce the formation of quasicrystalline particles. When there is no Fe/Ni enriched in particles, the structure is characterized as C15-Laves phase. When Fe/Ni is as quasicrystalline core, a stable core-shell quasicrystalline structure with Al-Fe-Ni nucleus and Mg-Cu-Zn shell can be formed. (4) Investigation on the regulation of nanoscale Laves precipitates’ growth. To regulate the defect structure of the precipitates, rare earth element Y was added in Al-Zn-Mg alloys and its influence on the precipitation behavior was investigated. The addition of Y element can dynamically combine with different alloying elements during aging process, which can refine the size of precipitate and further improve the nucleation rate and precipitation rate of the precipitates. |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:196404 |
Serial |
7631 |
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Author |
Poppe, R. |
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Title |
Refining short-range order parameters from diffuse electron scattering |
Type |
Doctoral thesis |
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Year |
2023 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
iv, 150 p. |
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Keywords |
Doctoral thesis; Electron microscopy for materials research (EMAT) |
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Abstract |
Electrons, X-rays and neutrons that pass through a thin crystalline sample will be diffracted. Diffraction patterns of crystalline materials contain Bragg reflections (sharp discrete intensity maxima) and diffuse scattering (a weak continuous background). The Bragg reflections contain information about the average crystal structure (the type of atoms and the average atomic positions), whereas the diffuse scattering contains information about the short-range order (deviations from the average crystal structure that are ordered on a local scale). Because the properties of many materials depend on the short-range order, refining short-range order parameters is essential for understanding and optimizing material properties. The refinement of short-range order parameters has previously been applied to the diffuse scattering in single-crystal X-ray and single-crystal neutron diffraction data but not yet to the diffuse scattering in single-crystal electron diffraction data. In this work, we will verify the possibility to refine short-range order parameters from the diffuse scattering in single-crystal electron diffraction data. Electron diffraction allows to acquire data on submicron-sized crystals, which are too small to be investigated with single-crystal X-ray and single-crystal neutron diffraction. In the first part of this work, we will refine short-range order parameters from the one-dimensional diffuse scattering in electron diffraction data acquired on the lithium-ion battery cathode material Li1.2Ni0.13Mn0.54Co0.13O2. The number of stacking faults and the twin percentages will be refined from the diffuse scattering using a Monte Carlo refinement. We will also describe a method to determine the spinel/layered phase ratio from the intensities of the Bragg reflections in electron diffraction data. In the second part of this work, we will refine short-range order parameters from the three-dimensional diffuse scattering in both single-crystal electron and single-crystal X-ray diffraction data acquired on Nb0.84CoSb. The correlations between neighbouring vacancies and the displacements of Sb and Co atoms will be refined from the diffuse scattering using a Monte Carlo refinement and a three-dimensional difference pair distribution function refinement. The effect of different experimental parameters on the spatial resolution of the observed diffuse scattering will also be investigated. Finally, the model of the short-range Nb-vacancy order in Nb0.84CoSb will also be applied to LiNi0.5Sn0.3Co0.2O2. |
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UA @ admin @ c:irua:200610 |
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Nakazato, R.; Matsumoto, K.; Yamaguchi, N.; Cavallo, M.; Crocella, V.; Bonino, F.; Quintelier, M.; Hadermann, J.; Rosero-Navarro, N.C.; Miura, A.; Tadanaga, K. |
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CO2 Electrochemical Reduction with Zn-Al Layered Double Hydroxide-Loaded Gas-Diffusion Electrode (Supporting Information) |
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2023 |
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Dataset; Electron microscopy for materials research (EMAT) |
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Carbon dioxide electrochemical reduction (CO2ER) has attracted considerable attention as a technology to recycle CO2 into raw materials for chemicals using renewable energies. We recently found that Zn-Al layered double hydroxides (Zn-Al LDH) have the CO-forming CO2ER activity. However, the activity was only evaluated by using the liquid-phase CO2ER. In this study, Ni-Al and Ni-Fe LDHs as well as Zn-Al LDH were synthesized using a facile coprecipitation process and the gas-phase CO2ER with the LDH-loaded gas-diffusion electrode (GDE) was examined. The products were characterized by XRD, STEM-EDX, BF-TEM and ATR-IR spectroscopy. In the ATR-IR results, the interaction of CO2 with Zn-Al LDH showed a different carbonates evolution with respect to other LDHs, suggesting a different electrocatalytic activity. The LDH-loaded GDE was prepared by simple drop-casting of a catalyst ink onto carbon paper. For gas-phase CO2ER, only Zn-Al LDH exhibited the CO2ER activity for carbon monoxide (CO) formation. By using different potassium salt electrolytes affording neutral to strongly basic conditions, such as KCl, KHCO3 and KOH, the gas-phase CO2ER with Zn-Al LDH-loaded GDE showed 1.3 to 2.1 times higher partial current density for CO formation than the liquid-phase CO2ER. |
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Grünewald, L.; Chezganov, D.; De Meyer, R.; Orekhov, A.; Van Aert, S.; Bogaerts, A.; Bals, S.; Verbeeck, J. |
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Supplementary Information for “In-situ Plasma Studies using a Direct Current Microplasma in a Scanning Electron Microscope” |
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2023 |
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Dataset; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Supplementary information for the article “In-situ Plasma Studies using a Direct Current Microplasma in a Scanning Electron Microscope” containing the videos of in-situ SEM imaging (mp4 files), raw data/images, and Jupyter notebooks (ipynb files) for data treatment and plots. Link to the preprint: https://doi.org/10.48550/arXiv.2308.15123 Explanation of the data files can be found in the Information.pdf file. The Videos folder contains the in-situ SEM image series mentioned in the paper. If there are any questions/bugs, feel free to contact me at lukas.grunewaldatuantwerpen.be |
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UA @ admin @ c:irua:203389 |
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Friedrich, T. |
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Quantifying atomic structures using neural networks from 4D scanning transmission electron microscopy (STEM) datasets |
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2023 |
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Doctoral thesis; Electron microscopy for materials research (EMAT) |
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Nanoscience and nanotechnologies are of immense importance across many fields of science and for numerous practical applications. In this context, scanning transmission electron microscopy (STEM) and 4D-STEM are among the most powerful characterization methods at the atomic scale. Annular dark-field (ADF)-STEM can be used to quantify atomic structures in 3D by counting atoms based on a single projection image. In 4D-STEM a full diffraction pattern is recorded at each scan step, which enables more dose efficient imaging and the utilization of various advanced imaging modalities, which can however be complex and slow. Both, STEM and 4D-STEM suffer from noise and distortions. In the first section of this work the most important of these distortions are discussed and it is shown how image restoration with a dedicated convolutional neural network (CNN) can be beneficial for atomic structure quantifications in ADF-STEM. In the second part, a new 4D-STEM imaging method real-time-integrated-centre-of-mass (riCOM) is introduced, which is a very dose-efficient and fast algorithm that enables unprecedented live-imaging capabilities for 4D-STEM. It is based on the integrated centre-of-mass approach, but is reformulated with variable integration ranges and optional filters, which allows for a tunable contrast transfer function. This enables the imaging of light and heavy elements simultaneously at very low doses. In the third part another new 4D-STEM method, coined AIRPI (AI-assisted rapid phase imaging) is introduced, which uses a CNN to retrieve a patch of the specimen's phase image for each scan position, based on the diffraction patterns in the probe's immediate surroundings. This allows also live imaging in principle and surpasses comparable state-of-the-art algorithms in terms of resolution also at low doses. Different atomic columns can be reliably distinguished over a wide range of atomic numbers, enabling a very good image interpretability. Further, AIRPI can recover low frequency image components, which preserves thickness information. This is a unique and important feature which could make quantitative 4D-STEM feasible. |
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UA @ admin @ c:irua:196826 |
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