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Author Van Gordon, K.; Ni, B.; Girod, R.; Mychinko, M.; Bevilacqua, F.; Bals, S.; Liz‐Marzán, L.M.
Title Single Crystal and Pentatwinned Gold Nanorods Result in Chiral Nanocrystals with Reverse Handedness Type A1 Journal Article
Year 2024 Publication Angewandte Chemie International Edition Abbreviated Journal Angew Chem Int Ed
Volume (down) Issue Pages
Keywords A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Abstract Handedness is an essential attribute of chiral nanocrystals, having a major influence on their properties. During chemical growth, the handedness of nanocrystals is usually tuned by selecting the corresponding enantiomer of chiral molecules involved in asymmetric growth, often known as chiral inducers. We report that, even using the same chiral inducer enantiomer, the handedness of chiral gold nanocrystals can be reversed by using Au nanorod seeds with either single crystalline or pentatwinned structure. This effect holds for chiral growth induced both by amino acids and by chiral micelles. Although it was challenging to discern the morphological handedness for<italic>L</italic>‐cystine‐directed particles, even using electron tomography, both cases showed circular dichroism bands of opposite sign, with nearly mirrored chiroptical signatures for chiral micelle‐directed growth, along with quasi‐helical wrinkles of inverted handedness. These results expand the chiral growth toolbox with an effect that might be exploited to yield a host of interesting morphologies with tunable optical properties.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2024-05-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1433-7851 ISBN Additional Links
Impact Factor 16.6 Times cited Open Access
Notes Ana Sánchez-Iglesias is acknowledged for support in the synthesis of pentatwinned gold nanorods. The authors acknowledge financial support by the European Research Council (ERC CoG No. 815128 REALNANO to S.B.), from MCIN/AEI/10.13039/501100011033 (Grant PID2020- 117779RB-I00 to L.M.L.-M and FPI Fellowship PRE2021- 097588 to K.V.G.), and by KU Leuven (C14/22/085). This work has been funded by the European Union under Project 101131111—DELIGHT. Funding for open access charge: Universidade de Vigo/ CRUE-CISUG. Approved Most recent IF: 16.6; 2024 IF: 11.994
Call Number EMAT @ emat @ Serial 9129
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Author Chakraborty, J.; Chatterjee, A.; Molkens, K.; Nath, I.; Arenas Esteban, D.; Bourda, L.; Watson, G.; Liu, C.; Van Thourhout, D.; Bals, S.; Geiregat, P.; Van der Voort, P.
Title Decoding Excimer Formation in Covalent–Organic Frameworks Induced by Morphology and Ring Torsion Type A1 Journal Article
Year 2024 Publication Advanced Materials Abbreviated Journal Advanced Materials
Volume (down) Issue Pages
Keywords A1 Journal Article; Electron Microscopy for Materials Science (EMAT) ;
Abstract A thorough and quantitative understanding of the fate of excitons in covalent–organic frameworks (COFs) after photoexcitation is essential for their augmented optoelectronic and photocatalytic applications via precise structure tuning. The synthesis of a library of COFs having identical chemical backbone with impeded conjugation, but varied morphology and surface topography to study the effect of these physical properties on the photophysics of the materials is herein reported. The variation of crystallite size and surface topography substantified different aggregation pattern in the COFs, which leads to disparities in their photoexcitation and relaxation properties. Depending on aggregation, an inverse correlation between bulk luminescence decay time and exciton binding energy of the materials is perceived. Further transient absorption spectroscopic analysis confirms the presence of highly localized, immobile, Frenkel excitons (of diameter 0.3–0.5 nm) via an absence of annihilation at high density, most likely induced by structural torsion of the COF skeletons, which in turn preferentially relaxes via long‐lived (nanosecond to microsecond) excimer formation (in femtosecond scale) over direct emission. These insights underpin the importance of structural and topological design of COFs for their targeted use in photocatalysis.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001206226700001 Publication Date 2024-04-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0935-9648 ISBN Additional Links UA library record; WoS full record
Impact Factor 29.4 Times cited Open Access
Notes PVDV, JC, AC, and IN acknowledge the FWO-Vlaanderen for research grant G020521N and the research board of UGent (BOF) through a Concerted Research Action (GOA010-17). JC acknowledges UGent for BOF postdoctoral grant (2022.0032.01). AC acknowledges FWOVlaanderen for postdoctoral grant (12T7521N). KM, DVT and PG acknowledges FWOVlaanderen for research grant G0B2921N. SB and DAE acknowledge financial support from ERC Consolidator Grant Number 815128 REALNANO. CHL acknowledges China Scholarship Council doctoral grant (201908110280). PVDV acknowledges Hercules Project AUGE/17/07 for the UV VIS DRS spectrometer and UGent BASBOF BOF20/BAS/015 for the powder X-Ray Diffractometer. PG thanks UGent for support of the Core Facility NOLIMITS. Approved Most recent IF: 29.4; 2024 IF: 19.791
Call Number EMAT @ emat @c:irua:205967 Serial 9130
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Author Gao, Y.-J.; Jin, H.; Esteban, D.A.; Weng, B.; Saha, R.A.; Yang, M.-Q.; Bals, S.; Steele, J.A.; Huang, H.; Roeffaers, M.B.J.
Title 3D-cavity-confined CsPbBr₃ quantum dots for visible-light-driven photocatalytic C(sp³)-H bond activation Type A1 Journal article
Year 2024 Publication Carbon Energy Abbreviated Journal
Volume (down) Issue Pages e559
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Metal halide perovskite (MHP) quantum dots (QDs) offer immense potential for several areas of photonics research due to their easy and low-cost fabrication and excellent optoelectronic properties. However, practical applications of MHP QDs are limited by their poor stability and, in particular, their tendency to aggregate. Here, we develop a two-step double-solvent strategy to grow and confine CsPbBr3 QDs within the three-dimensional (3D) cavities of a mesoporous SBA-16 silica scaffold (CsPbBr3@SBA-16). Strong confinement and separation of the MHP QDs lead to a relatively uniform size distribution, narrow luminescence, and good ambient stability over 2 months. In addition, the CsPbBr3@SBA-16 presents a high activity and stability for visible-light-driven photocatalytic toluene C(sp(3))-H bond activation to produce benzaldehyde with similar to 730 mu mol g(-1) h(-1) yield rate and near-unity selectivity. Similarly, the structural stability of CsPbBr3@SBA-16 QDs is superior to that of both pure CsPbBr3 QDs and those confined in MCM-41 with 1D channels.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001223583600001 Publication Date 2024-05-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2637-9368 ISBN Additional Links UA library record; WoS full record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:206000 Serial 9133
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Author Yang, C.-Q.; Yin, Z.-W.; Li, W.; Cui, W.-J.; Zhou, X.-G.; Wang, L.-D.; Zhi, R.; Xu, Y.-Y.; Tao, Z.-W.; Sang, X.; Cheng, Y.-B.; Van Tendeloo, G.; Hu, Z.-Y.; Su, B.-L.
Title Atomically deciphering the phase segregation in mixed halide perovskite Type A1 Journal article
Year 2024 Publication Advanced functional materials Abbreviated Journal
Volume (down) Issue Pages 1-10
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Mixed-halide perovskites show promising applications in tandem solar cells owing to their adjustable bandgap. One major obstacle to their commercialization is halide phase segregation, which results in large open-circuit voltage deficiency and J-V hysteresis. However, the ambiguous interplay between structural origin and phase segregation often results in aimless and unspecific optimization strategies for the device's performance and stability. An atomic scale is directly figured out the abundant Ruddlesden-Popper anti-phase boundaries (RP-APBs) within a CsPbIBr2 polycrystalline film and revealed that phase segregation predominantly occurs at RP-APB-enriched interfaces due to the defect-mediated lattice strain. By compensating their structural lead halide, such RP-APBs are eliminated, and the decreasing of strain can be observed, resulting in the suppression of halide phase segregation. The present work provides the deciphering to precisely regulate the perovskite atomic structure for achieving photo-stable mixed halide wide-bandgap perovskites of high-efficiency tandem solar cell commercial applications. The phase segregation in mixed halide perovskite film predominantly occurs at Ruddlesden-Popper anti-phase boundaries (RP-APBs)-enriched interfaces due to the defect-mediated lattice strain. The RP-APBs defects can be eliminated by compensating for their structural lead halide deficiency, resulting in the suppression of halide phase segregation. image
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001200673300001 Publication Date 2024-04-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1616-301x ISBN Additional Links UA library record; WoS full record
Impact Factor 19 Times cited Open Access
Notes Approved Most recent IF: 19; 2024 IF: 12.124
Call Number UA @ admin @ c:irua:205509 Serial 9134
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Author Lelouche, S.N.K.; Lemir, I.; Biglione, C.; Craig, T.; Bals, S.; Horcajada, P.
Title AuNP/MIL-88B-NH₂ nanocomposite for the valorization of nitroarene by green catalytic hydrogenation Type A1 Journal article
Year 2024 Publication Chemistry: a European journal Abbreviated Journal
Volume (down) Issue Pages 1-10
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The efficiency of a catalytic process is assessed based on conversion, yield, and time effectiveness. However, these parameters are insufficient for evaluating environmentally sustainable research. As the world is urged to shift towards green catalysis, additional factors such as reaction media, raw material availability, sustainability, waste minimization and catalyst biosafety, need to be considered to accurately determine the efficacy and sustainability of the process. By combining the high porosity and versatility of metal organic frameworks (MOFs) and the activity of gold nanoparticles (AuNPs), efficient, cyclable and biosafe composite catalysts can be achieved. Thus, a composite based on AuNPs and the nanometric flexible porous iron(III) aminoterephthalate MIL-88B-NH2 was successfully synthesized and fully characterized. This nanocomposite was tested as catalyst in the reduction of nitroarenes, which were identified as anthropogenic water pollutants, reaching cyclable high conversion rates at short times for different nitroarenes. Both synthesis and catalytic reactions were performed using green conditions, and even further tested in a time-optimizing one-pot synthesis and catalysis experiment. The sustainability and environmental impact of the catalytic conditions were assessed by green metrics. Thus, this study provides an easily implementable synthesis, and efficient catalysis, while minimizing the environmental and health impact of the process.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001204094600001 Publication Date 2024-03-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0947-6539 ISBN Additional Links UA library record; WoS full record
Impact Factor 4.3 Times cited Open Access
Notes Approved Most recent IF: 4.3; 2024 IF: 5.317
Call Number UA @ admin @ c:irua:205426 Serial 9135
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Author Cioni, M.; Delle Piane, M.; Polino, D.; Rapetti, D.; Crippa, M.; Arslan Irmak, E.; Pavan, G.M.; Van Aert, S.; Bals, S.
Title Data for Sampling Real‐Time Atomic Dynamics in Metal Nanoparticles by Combining Experiments, Simulations, and Machine Learning Type Dataset
Year 2024 Publication Abbreviated Journal
Volume (down) Issue Pages
Keywords Dataset; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Even at low temperatures, metal nanoparticles (NPs) possess atomic dynamics that are key for their properties but challenging to elucidate. Recent experimental advances allow obtaining atomic‐resolution snapshots of the NPs in realistic regimes, but data acquisition limitations hinder the experimental reconstruction of the atomic dynamics present within them. Molecular simulations have the advantage that these allow directly tracking the motion of atoms over time. However, these typically start from ideal/perfect NP structures and, suffering from sampling limits, provide results that are often dependent on the initial/putative structure and remain purely indicative. Here, by combining state‐of‐the‐art experimental and computational approaches, how it is possible to tackle the limitations of both approaches and resolve the atomistic dynamics present in metal NPs in realistic conditions is demonstrated. Annular dark‐field scanning transmission electron microscopy enables the acquisition of ten high‐resolution images of an Au NP at intervals of 0.6 s. These are used to reconstruct atomistic 3D models of the real NP used to run ten independent molecular dynamics simulations. Machine learning analyses of the simulation trajectories allows resolving the real‐time atomic dynamics present within the NP. This provides a robust combined experimental/computational approach to characterize the structural dynamics of metal NPs in realistic conditions.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:205843 Serial 9143
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Author Wu, X.; Ding, J.; Cui, W.; Lin, W.; Xue, Z.; Yang, Z.; Liu, J.; Nie, X.; Zhu, W.; Van Tendeloo, G.; Sang, X.
Title Enhanced electrical properties of Bi2-xSbxTe3 nanoflake thin films through interface engineering Type A1 Journal article
Year 2024 Publication Energy & environment materials Abbreviated Journal
Volume (down) Issue Pages e12755-8
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The structure-property relationship at interfaces is difficult to probe for thermoelectric materials with a complex interfacial microstructure. Designing thermoelectric materials with a simple, structurally-uniform interface provides a facile way to understand how these interfaces influence the transport properties. Here, we synthesized Bi2-xSbxTe3 (x = 0, 0.1, 0.2, 0.4) nanoflakes using a hydrothermal method, and prepared Bi2-xSbxTe3 thin films with predominantly (0001) interfaces by stacking the nanoflakes through spin coating. The influence of the annealing temperature and Sb content on the (0001) interface structure was systematically investigated at atomic scale using aberration-corrected scanning transmission electron microscopy. Annealing and Sb doping facilitate atom diffusion and migration between adjacent nanoflakes along the (0001) interface. As such it enhances interfacial connectivity and improves the electrical transport properties. Interfac reactions create new interfaces that increase the scattering and the Seebeck coefficient. Due to the simultaneous optimization of electrical conductivity and Seebeck coefficient, the maximum power factor of the Bi1.8Sb0.2Te3 nanoflake films reaches 1.72 mW m(-1) K-2, which is 43% higher than that of a pure Bi2Te3 thin film.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001204495900001 Publication Date 2024-04-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:205438 Serial 9148
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Author Vlasov, E.
Title Exploiting secondary electrons in transmission electron microscopy for 3D characterization of nanoparticle morphologies Type Doctoral thesis
Year 2024 Publication Abbreviated Journal
Volume (down) Issue Pages x, 118 p.
Keywords Doctoral thesis; Electron microscopy for materials research (EMAT)
Abstract Electron tomography (ET) is an indispensable tool for determining the three-dimensional (3D) structure of nanomaterials in (scanning) transmission electron microscopy ((S)TEM). ET enables 3D characterization of a variety of nanomaterials across different fields, including life sciences, chemistry, solid-state physics, and materials science down to atomic resolution. However, the acquisition of a conventional tilt series for ET is a time-consuming process and thus cannot capture fast transformations of materials in realistic conditions. Moreover, only a limited number of nanoparticles (NPs) can be investigated, hampering a general understanding of the average properties of the material. Therefore, alternative characterization techniques that allow for high-resolution characterization of the surface structure without the need to acquire a full tilt series in ET are required which would enable a more time-efficient investigation with better statistical value. In the first part of this work, an alternative technique for the characterization of the morphology of NPs to improve the throughput and temporal resolution of ET is presented. The proposed technique exploits surface-sensitive secondary electron (SE) imaging in STEM employed using a modification of electron beam-induced current (EBIC) setup. The time- and dose efficiency of SEEBIC are tested in comparison with ET and superior spatial resolution is shown compared to conventional scanning electron microscopy. Finally, contrast artefacts arising in SEEBIC images are described, and their origin is discussed. The second part of my thesis focuses on real applications of the proposed technique and introduces a high-throughput methodology that combines images acquired by SEEBIC with quantitative image analysis to retrieve information about the helicity of gold nanorods. It shows that SEEBIC imaging overcomes the limitation of ET providing a general understanding of the connection between structure and chiroptical properties.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2024-06-17
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:204905 Serial 9149
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Author Xu, H.; Li, H.; Gauquelin, N.; Chen, X.; Wu, W.-F.; Zhao, Y.; Si, L.; Tian, D.; Li, L.; Gan, Y.; Qi, S.; Li, M.; Hu, F.; Sun, J.; Jannis, D.; Yu, P.; Chen, G.; Zhong, Z.; Radovic, M.; Verbeeck, J.; Chen, Y.; Shen, B.
Title Giant tunability of Rashba splitting at cation-exchanged polar oxide interfaces by selective orbital hybridization Type A1 Journal article
Year 2024 Publication Advanced materials Abbreviated Journal
Volume (down) Issue Pages
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract The 2D electron gas (2DEG) at oxide interfaces exhibits extraordinary properties, such as 2D superconductivity and ferromagnetism, coupled to strongly correlated electrons in narrow d-bands. In particular, 2DEGs in KTaO3 (KTO) with 5d t2g orbitals exhibit larger atomic spin-orbit coupling and crystal-facet-dependent superconductivity absent for 3d 2DEGs in SrTiO3 (STO). Herein, by tracing the interfacial chemistry, weak anti-localization magneto-transport behavior, and electronic structures of (001), (110), and (111) KTO 2DEGs, unambiguously cation exchange across KTO interfaces is discovered. Therefore, the origin of the 2DEGs at KTO-based interfaces is dramatically different from the electronic reconstruction observed at STO interfaces. More importantly, as the interface polarization grows with the higher order planes in the KTO case, the Rashba spin splitting becomes maximal for the superconducting (111) interfaces approximately twice that of the (001) interface. The larger Rashba spin splitting couples strongly to the asymmetric chiral texture of the orbital angular moment, and results mainly from the enhanced inter-orbital hopping of the t2g bands and more localized wave functions. This finding has profound implications for the search for topological superconductors, as well as the realization of efficient spin-charge interconversion for low-power spin-orbitronics based on (110) and (111) KTO interfaces. An unambiguous cation exchange is discovered across the interfaces of (001), (110), and (111) KTaO3 2D electron gases fabricated at room temperature. Remarkably, the (111) interfaces with the highest superconducting transition temperature also turn out to show the strongest electron-phonon interaction and the largest Rashba spin splitting. image
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001219658400001 Publication Date 2024-03-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0935-9648 ISBN Additional Links UA library record; WoS full record
Impact Factor 29.4 Times cited Open Access
Notes Approved Most recent IF: 29.4; 2024 IF: 19.791
Call Number UA @ admin @ c:irua:206037 Serial 9152
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Author Wang, G.; Xie, C.; Wang, H.; Li, Q.; Xia, F.; Zeng, W.; Peng, H.; Van Tendeloo, G.; Tan, G.; Tian, J.; Wu, J.
Title Mitigated oxygen loss in lithium-rich manganese-based cathode enabled by strong Zr-O affinity Type A1 Journal article
Year 2024 Publication Advanced functional materials Abbreviated Journal
Volume (down) Issue Pages 2313672
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Oxygen loss is a serious problem of lithium-rich layered oxide (LLO) cathodes, as the high capacity of LLO relies on reversible oxygen redox. Oxygen release can occur at the surface leading to the formation of spinel or rock salt structures. Also, the lattice oxygen will usually become unstable after long cycling, which remains a major roadblock in the application of LLO. Here, it is shown that Zr doping is an effective strategy to retain lattice oxygen in LLO due to the high affinity between Zr and O. A simple sol-gel method is used to dope Zr4+ into the LLOs to adjust the local electronic structure and inhibit the diffusion of oxygen anions to the surface during cycling. Compared with untreated LLOs, LLO-Zr cathodes exhibit a higher cycling stability, with 94% capacity retention after 100 cycles at 0.4 C, up to 223 mAh g-1 at 1 C, and 88% capacity retention after 300 cycles. Theoretical calculations show that due to the strong Zr-O covalent bonding, the formation energy of oxygen vacancies has effectively increased and the loss of lattice oxygen under high voltage can be suppressed. This study provides a simple method for developing high-capacity and cyclability Li-rich cathode materials for lithium-ion batteries. Oxygen release can occur at the cathode surface leading to the formation of spinel or rock salt structures. Here, it is shown that Zr doping is an effective strategy to retain lattice oxygen in lithium-rich layered oxides (LLO) due to the high affinity between Zr and O. LLO-Zr exhibit higher cycling stability, with 88% capacity retention after 300 cycles at 1 C. image
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001159843800001 Publication Date 2024-02-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1616-301x ISBN Additional Links UA library record; WoS full record
Impact Factor 19 Times cited Open Access
Notes Approved Most recent IF: 19; 2024 IF: 12.124
Call Number UA @ admin @ c:irua:203812 Serial 9161
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Author Lu, Q.
Title Precipitation behavior and heat resistance properties of Al-Cu-Mg-Ag-(Si) alloy Type Doctoral thesis
Year 2024 Publication Abbreviated Journal
Volume (down) Issue Pages VIII, 212 p.
Keywords Doctoral thesis; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract With the rapid increase in the speed of new-generation aerospace vehicles, conventional heat-resistant aluminum alloys cannot meet the long-term service of the equipment. Therefore, the development of new high-strength heat-resistant aluminum alloys is of great strategic for the sustainable and high-quality development of industries. Al-Cu-Mg-Ag alloy is an age-hardenable heat-resistant aluminum alloy and has high strength and heat resistance. The addition of alloying elements such as Si and Sc to Al-Cu-Mg-Ag alloy introduces a competitive relationship among the σ-Al5Cu6Mg2, θ′-Al2Cu, and Ω phases. Therefore, a systematic investigation of precipitation behavior and heat resistance of Al-Cu-Mg-Ag-(Si) is essential for guiding the design of high-strength heat-resistant aluminum alloys. Combined characterization testing methods such as scanning electron microscopy, transmission electron microscopy, atom probe tomography, microhardness testing, and tensile testing with simulation calculation methods such as calculation of phase diagram, first-principles calculations, and Ab initio molecular dynamics, the effects of heat treatment processes and element content on the precipitation behavior, mechanical properties, and heat resistance of Al-Cu-Mg-Ag-(Si) alloys were systematically investigated. Furthermore, a multiple interface segregation structure was constructed at the θ′/Al interface, and a new Al-Cu-Mg-Ag-Si-Sc alloy with synergistically improved strength and heat resistance was developed. The main conclusions are as follows: (1) Based on the Kampmann-Wagner-Numerical theory, the relationship between the coarsening rate of the Ω phase and the aging process was analyzed, revealing for the first time that the critical size of Ω phase ( ) under thermal exposure temperature was the key factor determining the coarsening rate of Ω phase during long time thermal exposure heat treatment. After artificial ageing, when the size of Ω phase was smaller than the critical size , the dissolution of smaller Ω phase leaded to a rapid decrease in the number density of Ω phases, thereby reducing the heat resistance of the alloy. When the size of Ω phase was greater than or equal to the critical size , the coarsening rate of Ω phase was consistent, but a larger initial size would result in a larger final size after long-term thermal exposure. Therefore, the closer the size of Ω phase in the alloy is to the critical size under heat exposure temperature, the better the heat resistance of the alloy. (2) A concept of constructing a multiple interface segregation structure at the precipitate/matrix interface was proposed, and based on this concept, a multiple interface segregation structure containing the C/L-AlMgSiCu interfacial phase, newly discovered χ-AgMg interfacial phase, and Sc segregation layer was successfully constructed at the θ′/Al interface. The existence of the multiple interface segregation structure ensured that the designed Al-Cu-Mg-Ag-Si-Sc alloy maintains a yield strength of 400 MPa after thermal exposure at 200 C for 100 h, with a strength retention rate of 97%, creating a new record for the synergistic improvement of strength and heat resistance in aluminum alloys. In addition, combining transmission electron microscopy ex-situ/in-situ characterization with first-principles calculations, it is shown that the χ-AgMg interface phase will be destroyed due to the diffusion of the outer Ag layer during thermal exposure, and gradually dissolve into the matrix, but it can still delay the coarsening behavior of θ′-Al2Cu phase. (3) The criteria for determining whether Ω phase can precipitate are updated in Al-Cu-Mg-Ag-Si alloys with low Mg/Si ratio based on phase diagram thermodynamic calculations and multi-scale structural characterization. When W(Mg)/W(Si) > 1.4 and X(Ag)/X(Mgexcess) > 1, Ω phase can precipitate in Al-Cu-Mg-Ag-Si alloys, where X(Mgexcess) represents the atomic percentage of residual Mg elements after the formation of the AlMgSiCu quaternary precipitate phase C/L phase in the supersaturated solid solution, and the W(Mg) is the mass fraction of Mg in the supersaturated solid solution before artificial ageing. (4) The effects of alloy element content on precipitation behavior and heat resistance of Al-Cu-Mg-Ag-Si alloys were systematically analyzed. Critical conditions for the precipitation of σ-Al5Cu6Mg2 and Ω phase in Al-Cu-Mg-Ag-Si alloys are revealed. Based on calculation of phase diagram results, the conditions for precipitating σ-Al5Cu6Mg2 phase in the alloy are: ① W(Mg)/W(Si) > 1.8; ② W(Cu) > 2.7W(Mg) – 5W(Si). When W(Mg)/W(Si) < 1.8, the alloy is mainly precipitated with C/L/Q′-AlMgSiCu. When W(Cu) < 2.7W(Mg) – 5W(Si), the alloy will generate GPB zone. In addition, W(Ag)/W(Si) > 4 is the critical condition which the Ω phase can the main precipitates in Al-Cu-Mg-Ag-Si alloys. Furthermore, the correlation between precipitate types and heat resistance was summarized, showing that Al-Cu-Mg-Ag-(Si) alloys with Ω phase as the main strengthening phase are more suitable for the preparation of structures with short service time but high temperature, while Al-Cu-Mg-Ag-(Si) alloys with low Mg content and multiple segregation structures are more suitable for structures requiring long-term service at medium to high temperatures. This study, for the first time, combines calculation of phase diagram with multi-scale microstructure characterization, systematically unraveling the effects of element content on precipitation behavior, strength, and heat resistance of Al-Cu-Mg-Ag-(Si) alloys. In addition, a concept of constructing a multiple interface segregation structure at the precipitate/matrix interface was proposed to synergistically improve alloy strength and heat resistance. This work provides theoretical guidance for optimizing the composition and processing of Al-Cu-Mg-Ag-(Si) alloy and regulating the microstructure. Furthermore, it also offers new ideas and theoretical guidance for the development of novel high-strength heat-resistant alloys in other systems.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:206180 Serial 9167
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Author Cioni, M.; Delle Piane, M.; Polino, D.; Rapetti, D.; Crippa, M.; Arslan Irmak, E.; Van Aert, S.; Bals, S.; Pavan, G.M.
Title Sampling real-time atomic dynamics in metal nanoparticles by combining experiments, simulations, and machine learning Type A1 Journal article
Year 2024 Publication Advanced Science Abbreviated Journal
Volume (down) Issue Pages 1-13
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract Even at low temperatures, metal nanoparticles (NPs) possess atomic dynamics that are key for their properties but challenging to elucidate. Recent experimental advances allow obtaining atomic-resolution snapshots of the NPs in realistic regimes, but data acquisition limitations hinder the experimental reconstruction of the atomic dynamics present within them. Molecular simulations have the advantage that these allow directly tracking the motion of atoms over time. However, these typically start from ideal/perfect NP structures and, suffering from sampling limits, provide results that are often dependent on the initial/putative structure and remain purely indicative. Here, by combining state-of-the-art experimental and computational approaches, how it is possible to tackle the limitations of both approaches and resolve the atomistic dynamics present in metal NPs in realistic conditions is demonstrated. Annular dark-field scanning transmission electron microscopy enables the acquisition of ten high-resolution images of an Au NP at intervals of 0.6 s. These are used to reconstruct atomistic 3D models of the real NP used to run ten independent molecular dynamics simulations. Machine learning analyses of the simulation trajectories allow resolving the real-time atomic dynamics present within the NP. This provides a robust combined experimental/computational approach to characterize the structural dynamics of metal NPs in realistic conditions. Experimental and computational techniques are bridged to unveil atomic dynamics in gold nanoparticles (NPs), using annular dark-field scanning transmission electron microscopy and molecular dynamics simulations informed by machine learning. The approach provides unprecedented insights into the real-time structural behaviors of NPs, merging state-of-the-art techniques to accurately characterize their dynamics under realistic conditions. image
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001206888000001 Publication Date 2024-04-24
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2198-3844 ISBN Additional Links UA library record; WoS full record
Impact Factor 15.1 Times cited Open Access
Notes This work was supported by the funding received by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 818776- DYNAPOL, no. 770887 PICOMETRICS and no. 815128 REALNANO). The authors also acknowledge the computational resources provided by the Swiss National Supercomputing Center (CSCS), by CINECA, and the Research Foundation Flanders (FWO, Belgium) G.0346.21N. Approved Most recent IF: 15.1; 2024 IF: 9.034
Call Number UA @ admin @ c:irua:205442 Serial 9171
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Author Arisnabarreta, N.; Hao, Y.; Jin, E.; Salame, A.; Muellen, K.; Robert, M.; Lazzaroni, R.; Van Aert, S.; Mali, K.S.; De Feyter, S.
Title Single-layered imine-linked porphyrin-based two-dimensional covalent organic frameworks targeting CO₂ reduction Type A1 Journal article
Year 2024 Publication Advanced energy materials Abbreviated Journal
Volume (down) Issue Pages
Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Abstract The reduction of carbon dioxide (CO2) using porphyrin-containing 2D covalent organic frameworks (2D-COFs) catalysts is widely explored nowadays. While these framework materials are normally fabricated as powders followed by their uncontrolled surface heterogenization or directly grown as thin films (thickness >200 nm), very little is known about the performance of substrate-supported single-layered (approximate to 0.5 nm thickness) 2D-COFs films (s2D-COFs) due to its highly challenging synthesis and characterization protocols. In this work, a fast and straightforward fabrication method of porphyrin-containing s2D-COFs is demonstrated, which allows their extensive high-resolution visualization via scanning tunneling microscopy (STM) in liquid conditions with the support of STM simulations. The as-prepared single-layered film is then employed as a cathode for the electrochemical reduction of CO2. Fe porphyrin-containing s2D-COF@graphite used as a single-layered heterogeneous catalyst provided moderate-to-high carbon monoxide selectivity (82%) and partial CO current density (5.1 mA cm(-2)). This work establishes the value of using single-layered films as heterogene ous catalysts and demonstrates the possibility of achieving high performance in CO2 reduction even with extremely low catalyst loadings.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos 001177577200001 Publication Date 2024-02-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1614-6832; 1614-6840 ISBN Additional Links UA library record; WoS full record
Impact Factor 27.8 Times cited Open Access
Notes N.A. acknowledges a postdoctoral fellowship from the Research Foundation- Flanders (FWO) via grant 12ZS623N. S.D.F. acknowledges support from FWO (G0A4120N, G0H2122N, G0A5U24N), KU Leuven Internal Funds (grants C14/18/06, C14/19/079, C14/23/090), European Union under the Horizon Europe grant 101046231 (FantastiCOF), and M-ERA.NET via FWO (G0K9822N). S.D.F., K.M., Y.H., R.L., and S.V.A. were thankful to the FWO and FNRS for the financial support through the EOS program (grant 30489208, 40007495). Research in Mons was also supported by the Belgian National Fund for Scientific Research (FRS-FNRS) within the Consortium des Équipements de Calcul Intensif- CÉCI, and by the Walloon Region (ZENOBE and LUCIA Tier-1 supercomputers). E.J. appreciated the support from the Alexander von Humboldt Foundation, the Max Planck Society, the FLAG-ERA Grant OPERA by DFG 437130745, the National Natural Science Foundation of China (22288101), and the 111 Project (B17020). Partial financial support to M.R. from the Institut Universitaire de France (IUF) was warmly thanked. Approved Most recent IF: 27.8; 2024 IF: 16.721
Call Number UA @ admin @ c:irua:204856 Serial 9172
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Author Brognara, A.; Kashiwar, A.; Jung, C.; Zhang, X.; Ahmadian, A.; Gauquelin, N.; Verbeeck, J.; Djemia, P.; Faurie, D.; Dehm, G.; Idrissi, H.; Best, J.P.; Ghidelli, M.
Title Tailoring mechanical properties and shear band propagation in ZrCu metallic glass nanolaminates through chemical heterogeneities and interface density Type A1 Journal article
Year 2024 Publication Small Structures Abbreviated Journal
Volume (down) Issue Pages 2400011-11
Keywords A1 Journal article; Electron microscopy for materials research (EMAT)
Abstract The design of high‐performance structural thin films consistently seeks to achieve a delicate equilibrium by balancing outstanding mechanical properties like yield strength, ductility, and substrate adhesion, which are often mutually exclusive. Metallic glasses (MGs) with their amorphous structure have superior strength, but usually poor ductility with catastrophic failure induced by shear bands (SBs) formation. Herein, we introduce an innovative approach by synthesizing MGs characterized by large and tunable mechanical properties, pioneering a nanoengineering design based on the control of nanoscale chemical/structural heterogeneities. This is realized through a simplified model Zr 24 Cu 76 /Zr 61 Cu 39 , fully amorphous nanocomposite with controlled nanoscale periodicity ( Λ , from 400 down to 5 nm), local chemistry, and glass–glass interfaces, while focusing in‐depth on the SB nucleation/propagation processes. The nanolaminates enable a fine control of the mechanical properties, and an onset of crack formation/percolation (>1.9 and 3.3%, respectively) far above the monolithic counterparts. Moreover, we show that SB propagation induces large chemical intermixing, enabling a brittle‐to‐ductile transition when Λ  ≤ 50 nm, reaching remarkably large plastic deformation of 16% in compression and yield strength ≈2 GPa. Overall, the nanoengineered control of local heterogeneities leads to ultimate and tunable mechanical properties opening up a new approach for strong and ductile materials.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Wos Publication Date 2024-05-20
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2688-4062 ISBN Additional Links UA library record
Impact Factor Times cited Open Access
Notes Approved Most recent IF: NA
Call Number UA @ admin @ c:irua:205798 Serial 9176
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