| Records |
| Author |
Cui, W.; Lin, W.; Lu, W.; Liu, C.; Gao, Z.; Ma, H.; Zhao, W.; Van Tendeloo, G.; Zhao, W.; Zhang, Q.; Sang, X. |
| Title |
Direct observation of cation diffusion driven surface reconstruction at van der Waals gaps |
Type |
A1 Journal article |
| Year |
2023 |
Publication |
Nature communications |
Abbreviated Journal |
|
| Volume |
14 |
Issue |
1 |
Pages |
554-10 |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
| 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. |
| 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 |
001076227200001 |
Publication Date |
2023-02-02 |
| Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2041-1723 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
16.6 |
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
Most recent IF: 16.6; 2023 IF: 12.124 |
| Call Number |
UA @ admin @ c:irua:201342 |
Serial |
9021 |
| Permanent link to this record |
| |
|
| |
| Author |
Jenkinson, K.; Spadaro, M.C.; Golovanova, V.; Andreu, T.; Morante, J.R.; Arbiol, J.; Bals, S. |
| Title |
Direct operando visualization of metal support interactions induced by hydrogen spillover during CO₂ hydrogenation |
Type |
A1 Journal article |
| Year |
2023 |
Publication |
Advanced materials |
Abbreviated Journal |
|
| Volume |
35 |
Issue |
51 |
Pages |
2306447-10 |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
| Abstract |
The understanding of catalyst active sites is a fundamental challenge for the future rational design of optimized and bespoke catalysts. For instance, the partial reduction of Ce4+ surface sites to Ce3+ and the formation of oxygen vacancies are critical for CO2 hydrogenation, CO oxidation, and the water gas shift reaction. Furthermore, metal nanoparticles, the reducible support, and metal support interactions are prone to evolve under reaction conditions; therefore a catalyst structure must be characterized under operando conditions to identify active states and deduce structure-activity relationships. In the present work, temperature-induced morphological and chemical changes in Ni nanoparticle-decorated mesoporous CeO2 by means of in situ quantitative multimode electron tomography and in situ heating electron energy loss spectroscopy, respectively, are investigated. Moreover, operando electron energy loss spectroscopy is employed using a windowed gas cell and reveals the role of Ni-induced hydrogen spillover on active Ce3+ site formation and enhancement of the overall catalytic performance. |
| 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 |
001106139400001 |
Publication Date |
2023-10-22 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| 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 |
OpenAccess |
| Notes |
|
Approved |
Most recent IF: 29.4; 2023 IF: 19.791 |
| Call Number |
UA @ admin @ c:irua:201143 |
Serial |
9022 |
| Permanent link to this record |
| |
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| |
| Author |
Liang, Z.; Batuk, M.; Orlandi, F.; Manuel, P.; Hadermann, J.; Hayward, M.A. |
| Title |
Disproportionation of Co2+ in the topochemically reduced oxide LaSrCoRuO₅ |
Type |
A1 Journal article |
| Year |
2024 |
Publication |
Angewandte Chemie: international edition in English |
Abbreviated Journal |
|
| Volume |
63 |
Issue |
6 |
Pages |
e202313067-5 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Complex transition-metal oxides exhibit a wide variety of chemical and physical properties which are a strong function the local electronic states of the transition-metal centres, as determined by a combination of metal oxidation state and local coordination environment. Topochemical reduction of the double perovskite oxide, LaSrCoRuO6, using Zr, yields LaSrCoRuO5. This reduced phase contains an ordered array of apex-linked square-based pyramidal Ru3+O5, square-planar Co1+O4 and octahedral Co3+O6 units, consistent with the coordination-geometry driven disproportionation of Co2+. Coordination-geometry driven disproportionation of d(7) transition-metal cations (e.g. Rh2+, Pd3+, Pt3+) is common in complex oxides containing 4d and 5d metals. However, the weak ligand field experienced by a 3d transition-metal such as cobalt leads to the expectation that d(7+) Co2+ should be stable to disproportionation in oxide environments, so the presence of Co1+O4 and Co3+O6 units in LaSrCoRuO5 is surprising. Low-temperature measurements indicate LaSrCoRuO5 adopts a ferromagnetically ordered state below 120 K due to couplings between S=(1)/(2) Ru3+ and S=1 Co1+. |
| 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 |
001136579700001 |
Publication Date |
2023-12-13 |
| Series Editor |
|
Series Title |
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Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1433-7851; 0570-0833 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
| Impact Factor |
16.6 |
Times cited |
|
Open Access |
Not_Open_Access |
| Notes |
|
Approved |
Most recent IF: 16.6; 2024 IF: 11.994 |
| Call Number |
UA @ admin @ c:irua:202801 |
Serial |
9023 |
| Permanent link to this record |
| |
|
| |
| Author |
Manzaneda-Gonzalez, V.; Jenkinson, K.; Pena-Rodriguez, O.; Borrell-Grueiro, O.; Trivino-Sanchez, S.; Banares, L.; Junquera, E.; Espinosa, A.; Gonzalez-Rubio, G.; Bals, S.; Guerrero-Martinez, A. |
| Title |
From multi- to single-hollow trimetallic nanocrystals by ultrafast heating |
Type |
A1 Journal article |
| Year |
2023 |
Publication |
Chemistry of materials |
Abbreviated Journal |
|
| Volume |
35 |
Issue |
22 |
Pages |
9603-9612 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Metal nanocrystals (NCs) display unique physicochemical features that are highly dependent on nanoparticle dimensions, anisotropy, structure, and composition. The development of synthesis methodologies that allow us to tune such parameters finely emerges as crucial for the application of metal NCs in catalysis, optical materials, or biomedicine. Here, we describe a synthetic methodology to fabricate hollow multimetallic heterostructures using a combination of seed-mediated growth routes and femtosecond-pulsed laser irradiation. The envisaged methodology relies on the coreduction of Ag and Pd ions on gold nanorods (Au NRs) to form Au@PdAg core-shell nanostructures containing small cavities at the Au-PdAg interface. The excitation of Au@PdAg NRs with low fluence femtosecond pulses was employed to induce the coalescence and growth of large cavities, forming multihollow anisotropic Au@PdAg nanostructures. Moreover, single-hollow alloy AuPdAg could be achieved in high yield by increasing the irradiation energy. Advanced electron microscopy techniques, energy-dispersive X-ray spectroscopy (EDX) tomography, X-ray absorption near-edge structure (XANES) spectroscopy, and finite differences in the time domain (FDTD) simulations allowed us to characterize the morphology, structure, and elemental distribution of the irradiated NCs in detail. The ability of the reported synthesis route to fabricate multimetallic NCs with unprecedented hollow nanostructures offers attractive prospects for the fabrication of tailored high-entropy alloy nanoparticles. |
| 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 |
|
Wos |
001110623500001 |
Publication Date |
2023-11-06 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0897-4756; 1520-5002 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
8.6 |
Times cited |
2 |
Open Access |
OpenAccess |
| Notes |
|
Approved |
Most recent IF: 8.6; 2023 IF: 9.466 |
| Call Number |
UA @ admin @ c:irua:202144 |
Serial |
9040 |
| Permanent link to this record |
| |
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| |
| Author |
Zhang, Z.; Lobato, I.; Brown, H.; Jannis, D.; Verbeeck, J.; Van Aert, S.; Nellist, P. |
| Title |
Generalised oscillator strength for core-shell electron excitation by fast electrons based on Dirac solutions |
Type |
Dataset |
| Year |
2023 |
Publication |
|
Abbreviated Journal |
|
| Volume |
|
Issue |
|
Pages |
|
| Keywords |
Dataset; Electron microscopy for materials research (EMAT) |
| 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. |
| 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 |
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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 |
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ISBN |
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Additional Links |
UA library record |
| Impact Factor |
|
Times cited |
|
Open Access |
Not_Open_Access |
| Notes |
|
Approved |
Most recent IF: NA |
| Call Number |
UA @ admin @ c:irua:203392 |
Serial |
9042 |
| Permanent link to this record |
| |
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| |
| Author |
Van Daele, S.; Hintjens, L.; Hoekx, S.; Bohlen, B.; Neukermans, S.; Daems, N.; Hereijgers, J.; Breugelmans, T. |
| Title |
How flue gas impurities affect the electrochemical reduction of CO₂ to CO and formate |
Type |
A1 Journal article |
| Year |
2024 |
Publication |
Applied catalysis : B : environmental |
Abbreviated Journal |
|
| Volume |
341 |
Issue |
|
Pages |
123345-10 |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Applied Electrochemistry & Catalysis (ELCAT); Electron microscopy for materials research (EMAT) |
| Abstract |
The electrochemical CO2 reduction offers a promising solution to convert waste CO2 into valuable products like CO and formate. However, CO2 capture and purification remains an energy intensive process and therefore the direct usage of industrially available waste CO2 streams containing SO2, NO and O2 impurities becomes more interesting. This work demonstrates an efficient (Faradaic efficiency > 90 %) and stable performance over 20 h with 200 ppm SO2 or NO in the feed gas stream. However, the addition of 1 % O2 to the CO2 feed causes a significant drop in Faradaic efficiency to C-products due to the competitive oxygen reduction reaction. A potential mitigation strategy is to operate at higher total current density to firstly reduce most O2 and achieve sufficient product output from CO2 reduction. These results aid in understanding the impact of flue gas impurities during CO2 electrolysis which is crucial for potentially bypassing the CO2 purification step. |
| 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 |
|
Wos |
001102999000001 |
Publication Date |
2023-10-01 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0926-3373 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
22.1 |
Times cited |
|
Open Access |
Not_Open_Access |
| Notes |
|
Approved |
Most recent IF: 22.1; 2024 IF: 9.446 |
| Call Number |
UA @ admin @ c:irua:199490 |
Serial |
9044 |
| Permanent link to this record |
| |
|
| |
| Author |
Van den Hoek, J.; Daems, N.; Arnouts, S.; Hoekx, S.; Bals, S.; Breugelmans, T. |
| Title |
Improving stability of CO₂ electroreduction by incorporating Ag NPs in N-doped ordered mesoporous carbon structures |
Type |
A1 Journal article |
| Year |
2024 |
Publication |
ACS applied materials and interfaces |
Abbreviated Journal |
|
| Volume |
16 |
Issue |
6 |
Pages |
6931-6947 |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT) |
| Abstract |
The electroreduction of carbon dioxide (eCO2RR) to CO using Ag nanoparticles as an electrocatalyst is promising as an industrial carbon capture and utilization (CCU) technique to mitigate CO2 emissions. Nevertheless, the long-term stability of these Ag nanoparticles has been insufficient despite initial high Faradaic efficiencies and/or partial current densities. To improve the stability, we evaluated an up-scalable and easily tunable synthesis route to deposit low-weight percentages of Ag nanoparticles (NPs) on and into the framework of a nitrogen-doped ordered mesoporous carbon (NOMC) structure. By exploiting this so-called nanoparticle confinement strategy, the nanoparticle mobility under operation is strongly reduced. As a result, particle detachment and agglomeration, two of the most pronounced electrocatalytic degradation mechanisms, are (partially) blocked and catalyst durability is improved. Several synthesis parameters, such as the anchoring agent, the weight percentage of Ag NPs, and the type of carbonaceous support material, were modified in a controlled manner to evaluate their respective impact on the overall electrochemical performance, with a strong emphasis on operational stability. The resulting powders were evaluated through electrochemical and physicochemical characterization methods, including X-ray diffraction (XRD), N2-physisorption, Inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy (SEM), SEM-energy-dispersive X-ray spectroscopy (SEM-EDS), high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), STEM-EDS, electron tomography, and X-ray photoelectron spectroscopy (XPS). The optimized Ag/soft-NOMC catalysts showed both a promising selectivity (∼80%) and stability compared with commercial Ag NPs while decreasing the loading of the transition metal by more than 50%. The stability of both the 5 and 10 wt % Ag/soft-NOMC catalysts showed considerable improvements by anchoring the Ag NPs on and into a NOMC framework, resulting in a 267% improvement in CO selectivity after 72 h (despite initial losses) compared to commercial Ag NPs. These results demonstrate the promising strategy of anchoring Ag NPs to improve the CO selectivity during prolonged experiments due to the reduced mobility of the Ag NPs and thus enhanced stability. |
| 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 |
|
Wos |
001158812100001 |
Publication Date |
2023-12-21 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1944-8244 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
| Impact Factor |
9.5 |
Times cited |
|
Open Access |
Not_Open_Access: Available from 21.06.2024 |
| Notes |
|
Approved |
Most recent IF: 9.5; 2024 IF: 7.504 |
| Call Number |
UA @ admin @ c:irua:202309 |
Serial |
9045 |
| Permanent link to this record |
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| |
| Author |
Hugenschmidt, M.; Jannis, D.; Kadu, A.A.; Grünewald, L.; De Marchi, S.; Perez-Juste, J.; Verbeeck, J.; Van Aert, S.; Bals, S. |
| Title |
Low-dose 4D-STEM tomography for beam-sensitive nanocomposites |
Type |
A1 Journal article |
| Year |
2023 |
Publication |
ACS materials letters |
Abbreviated Journal |
|
| Volume |
6 |
Issue |
1 |
Pages |
165-173 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Electron tomography is essential for investigating the three-dimensional (3D) structure of nanomaterials. However, many of these materials, such as metal-organic frameworks (MOFs), are extremely sensitive to electron radiation, making it difficult to acquire a series of projection images for electron tomography without inducing electron-beam damage. Another significant challenge is the high contrast in high-angle annular dark field scanning transmission electron microscopy that can be expected for nanocomposites composed of a metal nanoparticle and an MOF. This strong contrast leads to so-called metal artifacts in the 3D reconstruction. To overcome these limitations, we here present low-dose electron tomography based on four-dimensional scanning transmission electron microscopy (4D-STEM) data sets, collected using an ultrafast and highly sensitive direct electron detector. As a proof of concept, we demonstrate the applicability of the method for an Au nanostar embedded in a ZIF-8 MOF, which is of great interest for applications in various fields, including drug delivery. |
| 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 |
001141178500001 |
Publication Date |
2023-12-11 |
| Series Editor |
|
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 |
2639-4979 |
ISBN |
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Additional Links |
UA library record; WoS full record |
| Impact Factor |
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Times cited |
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Open Access |
Not_Open_Access |
| Notes |
This work was supported by the European Research Council (Grant 815128 REALNANO to S.B., Grant 770887 PICOMETRICS to S.V.A.). J.P.-J. and S.M. acknowledge financial support from the MCIN/AEI/10.13039/501100011033 (Grants No. PID2019-108954RB-I00) and EU Horizon 2020 research and innovation program under grant agreement no. 883390 (SERSing). J.V., S.B., S.V.A., and L.G. acknowledge funding from the Flemish government (iBOF-21-085 PERsist). |
Approved |
Most recent IF: NA |
| Call Number |
UA @ admin @ c:irua:202771 |
Serial |
9053 |
| Permanent link to this record |
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| |
| Author |
Johnson, G.; Yang, M.Y.; Liu, C.; Zhou, H.; Zuo, X.; Dickie, D.A.; Wang, S.; Gao, W.; Anaclet, B.; Perras, F.A.; Ma, F.; Zeng, C.; Wang, D.; Bals, S.; Dai, S.; Xu, Z.; Liu, G.; Goddard III, W.A.; Zhang, S. |
| Title |
Nanocluster superstructures assembled via surface ligand switching at high temperature |
Type |
A1 Journal article |
| Year |
2023 |
Publication |
Nature synthesis |
Abbreviated Journal |
|
| Volume |
2 |
Issue |
9 |
Pages |
828-837 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Superstructures with nanoscale building blocks, when coupled with precise control of the constituent units, open opportunities in rationally designing and manufacturing desired functional materials. Yet, synthetic strategies for the large-scale production of superstructures are scarce. We report a scalable and generalized approach to synthesizing superstructures assembled from atomically precise Ce24O28(OH)8 and other rare-earth metal-oxide nanoclusters alongside a detailed description of the self-assembly mechanism. Combining operando small-angle X-ray scattering, ex situ molecular and structural characterizations, and molecular dynamics simulations indicates that a high-temperature ligand-switching mechanism, from oleate to benzoate, governs the formation of the nanocluster assembly. The chemical tuning of surface ligands controls superstructure disassembly and reassembly, and furthermore, enables the synthesis of multicomponent superstructures. This synthetic approach, and the accurate mechanistic understanding, are promising for the preparation of superstructures for use in electronics, plasmonics, magnetics and catalysis. Synthesizing superstructures with precisely controlled nanoscale building blocks is challenging. Here the assembly of superstructures is reported from atomically precise Ce24O28(OH)8 and other rare-earth metal-oxide nanoclusters and their multicomponent combinations. A high-temperature ligand-switching mechanism controls the self-assembly. |
| 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 |
001124824000001 |
Publication Date |
2023-05-01 |
| 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 |
|
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
2 |
Open Access |
Not_Open_Access |
| Notes |
|
Approved |
Most recent IF: NA |
| Call Number |
UA @ admin @ c:irua:202180 |
Serial |
9060 |
| Permanent link to this record |
| |
|
| |
| Author |
Yu, C.-P. |
| Title |
Novel imaging methods of transmission electron microscopy based on electron beam scattering and modulation |
Type |
Doctoral thesis |
| Year |
2023 |
Publication |
|
Abbreviated Journal |
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| Volume |
|
Issue |
|
Pages |
x, 154 p. |
| Keywords |
Doctoral thesis; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
| 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. |
| 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 |
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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 |
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ISBN |
987-90-5728-534-7 |
Additional Links |
UA library record |
| Impact Factor |
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Times cited |
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Open Access |
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| Notes |
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Approved |
Most recent IF: NA |
| Call Number |
UA @ admin @ c:irua:200885 |
Serial |
9064 |
| Permanent link to this record |
| |
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| |
| Author |
Gao, C.; Hofer, C.; Pennycook, T.J. |
| Title |
On central focusing for contrast optimization in direct electron ptychography of thick samples |
Type |
A1 Journal article |
| Year |
2024 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
|
| Volume |
256 |
Issue |
|
Pages |
113879-7 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Ptychography provides high dose efficiency images that can reveal light elements next to heavy atoms. However, despite ptychography having an otherwise single signed contrast transfer function, contrast reversals can occur when the projected potential becomes strong for both direct and iterative inversion ptychography methods. It has recently been shown that these reversals can often be counteracted in direct ptychography methods by adapting the focus. Here we provide an explanation of why the best contrast is often found with the probe focused to the middle of the sample. The phase contribution due to defocus at each sample slice above and below the central plane in this configuration effectively cancels out, which can prevent contrast reversals when dynamical scattering effects are not overly strong. In addition we show that the convergence angle can be an important consideration for removal of contrast reversals in relatively thin samples. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
|
Editor |
|
| Language |
|
Wos |
001112166400001 |
Publication Date |
2023-11-03 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0304-3991 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.2 |
Times cited |
|
Open Access |
Not_Open_Access |
| Notes |
|
Approved |
Most recent IF: 2.2; 2024 IF: 2.843 |
| Call Number |
UA @ admin @ c:irua:202029 |
Serial |
9066 |
| Permanent link to this record |
| |
|
| |
| Author |
Kashiwar, A.; Arseenko, M.; Simar, A.; Idrissi, H. |
| Title |
On the role of microstructural defects on precipitation, damage, and healing behavior in a novel Al-0.5Mg2Si alloy |
Type |
A1 Journal article |
| Year |
2024 |
Publication |
Materials & design |
Abbreviated Journal |
|
| Volume |
239 |
Issue |
|
Pages |
112765-112769 |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
| Abstract |
A recently developed healable Al-Mg2Si designed by the programmed damage and repair (PDR) strategy is studied considering the role microstructural defects play on precipitation, damage, and healing. The alloy incorporates sacrificial Mg2Si particles that precipitate after friction stir processing (FSP). They act as damage localization sites and are healable based on the solid-state diffusion of Al-matrix. A combination of different transmission electron microscopy (TEM) imaging techniques enabled the visualization and quantification of various crystallographic defects and the spatial distribution of Mg2Si precipitates. Intragrain nucleation is found to be the dominant mechanism for precipitation during FSP whereas grain boundaries and subgrain boundaries mainly lead to coarsening of the precipitates. The statistical and spatial analyses of the damaged particles have shown particle fracture as the dominant damage mechanism which is strongly dependent on the size and aspect ratio of the particles whereas the damage was not found to depend on the location of the precipitates within the matrix. The damaged particles are associated with dislocations accumulated around them. The interplay of these dislocations is directly visualized during healing based on in situ TEM heating which revealed recovery in the matrix as an operative mechanism during the diffusion healing of the PDR alloy. |
| 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 |
|
Wos |
001194110200001 |
Publication Date |
2024-02-17 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0264-1275; 1873-4197 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
| Impact Factor |
8.4 |
Times cited |
|
Open Access |
Not_Open_Access |
| Notes |
|
Approved |
Most recent IF: 8.4; 2024 IF: 4.364 |
| Call Number |
UA @ admin @ c:irua:203298 |
Serial |
9068 |
| Permanent link to this record |
| |
|
| |
| Author |
Poppe, R. |
| Title |
Refining short-range order parameters from diffuse electron scattering |
Type |
Doctoral thesis |
| Year |
2023 |
Publication |
|
Abbreviated Journal |
|
| Volume |
|
Issue |
|
Pages |
iv, 150 p. |
| Keywords |
Doctoral thesis; Electron microscopy for materials research (EMAT) |
| 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. |
| 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 |
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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 |
|
| 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:200610 |
Serial |
9084 |
| Permanent link to this record |
| |
|
| |
| Author |
Ulu Okudur, F.; Batuk, M.; Hadermann, J.; Safari, M.; De Sloovere, D.; Kumar Mylavarapu, S.; Joos, B.; D'Haen, J.; Van Bael, M.K.; Hardy, A. |
| Title |
Solution-gel-based surface modification of LiNi0.5Mn1.5O4-δ with amorphous Li-Ti-O coating |
Type |
A1 Journal article |
| Year |
2023 |
Publication |
RSC advances |
Abbreviated Journal |
|
| Volume |
13 |
Issue |
47 |
Pages |
33146-33158 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
LNMO (LiNi0.5Mn1.5O4-delta) is a high-energy density positive electrode material for lithium ion batteries. Unfortunately, it suffers from capacity loss and impedance rise during cycling due to electrolyte oxidation and electrode/electrolyte interface instabilities at high operating voltages. Here, a solution-gel synthesis route was used to coat 0.5-2.5 mu m LNMO particles with amorphous Li-Ti-O (LTO) for improved Li conduction, surface structural stability and cyclability. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) analysis coupled with energy dispersive X-ray (EDX) showed Ti-rich amorphous coatings/islands or Ti-rich spinel layers on many of the LTO-modified LNMO facets, with a thickness varying from about 1 to 10 nm. The surface modification in the form of amorphous islands was mostly possible on high-energy crystal facets. Physicochemical observations were used to propose a molecular mechanism for the surface modification, combining insights from metalorganic chemistry with the crystallographic properties of LNMO. The improvements in functional properties were investigated in half cells. The cell impedance increased faster for the bare LNMO compared to amorphous LTO modified LNMO, resulting in R-ct values as high as 1247 Omega (after 1000 cycles) for bare LNMO, against 216 Omega for the modified material. At 10C, the modified material boosted a 15% increase in average discharge capacity. The improvements in electrochemical performance were attributed to the increase in electrochemically active surface area, as well as to improved HF-scavenging, resulting in the formation of protective byproducts, generating a more stable interface during prolonged cycling. |
| 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 |
|
| Language |
|
Wos |
001102666700001 |
Publication Date |
2023-11-09 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2046-2069 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
| Impact Factor |
3.9 |
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
Most recent IF: 3.9; 2023 IF: 3.108 |
| Call Number |
UA @ admin @ c:irua:202091 |
Serial |
9096 |
| Permanent link to this record |
| |
|
| |
| Author |
Grünewald, L.; Chezganov, D.; De Meyer, R.; Orekhov, A.; Van Aert, S.; Bogaerts, A.; Bals, S.; Verbeeck, J. |
| Title |
Supplementary Information for “In-situ Plasma Studies using a Direct Current Microplasma in a Scanning Electron Microscope” |
Type |
Dataset |
| Year |
2023 |
Publication |
|
Abbreviated Journal |
|
| Volume |
|
Issue |
|
Pages |
|
| Keywords |
Dataset; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
| Abstract |
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 |
| 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 |
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| Series Editor |
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Series Title |
|
Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
|
ISBN |
|
Additional Links |
UA library record |
| Impact Factor |
|
Times cited |
|
Open Access |
Not_Open_Access |
| Notes |
|
Approved |
Most recent IF: NA |
| Call Number |
UA @ admin @ c:irua:203389 |
Serial |
9100 |
| Permanent link to this record |
| |
|
| |
| Author |
Singh, A.; Yuan, B.; Rahman, M.H.; Yang, H.; De, A.; Park, J.Y.; Zhang, S.; Huang, L.; Mannodi-Kanakkithodi, A.; Pennycook, T.J.; Dou, L. |
| Title |
Two-dimensional halide Pb-perovskite-double perovskite epitaxial heterostructures |
Type |
A1 Journal article |
| Year |
2023 |
Publication |
Journal of the American Chemical Society |
Abbreviated Journal |
|
| Volume |
145 |
Issue |
36 |
Pages |
19885-19893 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Epitaxial heterostructures of two-dimensional (2D) halide perovskites offer a new platform for studying intriguing structural, optical, and electronic properties. However, difficulties with the stability of Pb- and Sn-based heterostructures have repeatedly slowed the progress. Recently, Pb-free halide double perovskites are gaining a lot of attention due to their superior stability and greater chemical diversity, but they have not been successfully incorporated into epitaxial heterostructures for further investigation. Here, we report epitaxial core-shell heterostructures via growing Pb-free double perovskites (involving combinations of Ag(I)-Bi(III), Ag-Sb, Ag-In, Na-Bi, Na-Sb, and Na-In) around Pb perovskite 2D crystals. Distinct from Pb-Pb and Pb-Sn perovskite heterostructures, growths of the Pb-free shell at 45 degrees on the (100) surface of the lead perovskite core are observed in all Pb-free cases. The in-depth structural analysis carried out with electron diffraction unequivocally demonstrates the growth of the Pb-free shell along the [110] direction of the Pb perovskite, which is likely due to the relatively lower surface energy of the (110) surface. Furthermore, an investigation of anionic interdiffusion across heterostructure interfaces under the influence of heat was carried out. Interestingly, halide anion diffusion in the Pb-free 2D perovskites is found to be significantly suppressed as compared to Pb-based 2D perovskites. The great structural tunability and excellent stability of Pb-free perovskite heterostructures may find uses in electronic and optoelectronic devices in the near future. |
| Address |
|
| Corporate Author |
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Thesis |
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| Publisher |
|
Place of Publication |
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Editor |
|
| Language |
|
Wos |
001060980300001 |
Publication Date |
2023-08-31 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0002-7863 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
15 |
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
Most recent IF: 15; 2023 IF: 13.858 |
| Call Number |
UA @ admin @ c:irua:200342 |
Serial |
9111 |
| Permanent link to this record |
| |
|
| |
| 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 |
|
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 |
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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 |
|
| 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 |
no |
| Call Number |
UA @ admin @ c:irua:206000 |
Serial |
9133 |
| Permanent link to this record |
| |
|
| |
| 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 |
|
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 |
| 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 |
|
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 |
|
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
no |
| Call Number |
UA @ admin @ c:irua:205509 |
Serial |
9134 |
| Permanent link to this record |
| |
|
| |
| 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 |
|
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 |
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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 |
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 |
|
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
no |
| Call Number |
UA @ admin @ c:irua:205426 |
Serial |
9135 |
| Permanent link to this record |
| |
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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 |
|
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 |
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| Corporate Author |
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Thesis |
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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 |
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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 |
|
ISBN |
|
Additional Links |
UA library record |
| Impact Factor |
|
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
no |
| Call Number |
UA @ admin @ c:irua:205843 |
Serial |
9143 |
| Permanent link to this record |
| |
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| |
| Author |
Morad, V.; Stelmakh, A.; Svyrydenko, M.; Feld, L.G.; Boehme, S.C.; Aebli, M.; Affolter, J.; Kaul, C.J.; Schrenker, N.J.; Bals, S.; Sahin, Y.; Dirin, D.N.; Cherniukh, I.; Raino, G.; Baumketner, A.; Kovalenko, M.V. |
| Title |
Designer phospholipid capping ligands for soft metal halide nanocrystals |
Type |
A1 Journal article |
| Year |
2024 |
Publication |
Nature |
Abbreviated Journal |
|
| Volume |
626 |
Issue |
|
Pages |
542-548 |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
| Abstract |
The success of colloidal semiconductor nanocrystals (NCs) in science and optoelectronics is inextricable from their surfaces. The functionalization of lead halide perovskite NCs1-5 poses a formidable challenge because of their structural lability, unlike the well-established covalent ligand capping of conventional semiconductor NCs6,7. We posited that the vast and facile molecular engineering of phospholipids as zwitterionic surfactants can deliver highly customized surface chemistries for metal halide NCs. Molecular dynamics simulations implied that ligand-NC surface affinity is primarily governed by the structure of the zwitterionic head group, particularly by the geometric fitness of the anionic and cationic moieties into the surface lattice sites, as corroborated by the nuclear magnetic resonance and Fourier-transform infrared spectroscopy data. Lattice-matched primary-ammonium phospholipids enhance the structural and colloidal integrity of hybrid organic-inorganic lead halide perovskites (FAPbBr3 and MAPbBr3 (FA, formamidinium; MA, methylammonium)) and lead-free metal halide NCs. The molecular structure of the organic ligand tail governs the long-term colloidal stability and compatibility with solvents of diverse polarity, from hydrocarbons to acetone and alcohols. These NCs exhibit photoluminescence quantum yield of more than 96% in solution and solids and minimal photoluminescence intermittency at the single particle level with an average ON fraction as high as 94%, as well as bright and high-purity (about 95%) single-photon emission. Phospholipids enhance the structural and colloidal integrity of hybrid organic-inorganic lead halide perovskites and lead-free metal halide nanocrystals, which then exhibit enhanced robustness and optical properties. |
| Address |
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| Corporate Author |
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Thesis |
|
| Publisher |
|
Place of Publication |
|
Editor |
|
| Language |
|
Wos |
001176943100001 |
Publication Date |
2023-12-18 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0028-0836; 1476-4687 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
|
Times cited |
|
Open Access |
|
| Notes |
|
Approved |
no |
| Call Number |
UA @ admin @ c:irua:204796 |
Serial |
9144 |
| Permanent link to this record |
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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 |
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| Volume |
|
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 |
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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 |
001204495900001 |
Publication Date |
2024-04-18 |
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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 |
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ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Times cited |
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Open Access |
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| Notes |
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Approved |
no |
| 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 |
|
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. |
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Thesis |
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Place of Publication |
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Editor |
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Wos |
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Publication Date |
2024-06-17 |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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ISBN |
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Additional Links |
UA library record |
| Impact Factor |
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Times cited |
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Open Access |
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| Notes |
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Approved |
no |
| 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 |
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| Volume |
|
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 |
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Thesis |
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Place of Publication |
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Editor |
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Wos |
001219658400001 |
Publication Date |
2024-03-13 |
| 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 |
|
| ISSN |
0935-9648 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
| Impact Factor |
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Times cited |
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Open Access |
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| Notes |
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Approved |
no |
| Call Number |
UA @ admin @ c:irua:206037 |
Serial |
9152 |
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| Author |
Bampouli, A.; Goris, Q.; Hussain, M.N.; Louisnard, O.; Stefanidis, G.D.; Van Gerven, T. |
| Title |
Importance of design and operating parameters in a sonication system for viscous solutions : effects of input power, horn tip diameter and reactor capacity |
Type |
A1 Journal article |
| Year |
2024 |
Publication |
Chemical engineering and processing |
Abbreviated Journal |
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| Volume |
198 |
Issue |
|
Pages |
109715-12 |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
| Abstract |
This study investigates the distribution of ultrasound (US) energy in a batch system for solutions with viscosity ranging from 1 to approximately 3000 mPas. Sonication was performed using horn type configurations operating at 20-30 kHz and rated power capacity of 50 or 200 W. Two different tip diameters (3 or 7 mm) and two insertion depths (35 or 25 mm) within vessels of different sizes ( approximate to 60 or 130 ml) were utilized. Additionally, a special conical tip design was employed. For each experimental setup, the calorimetric efficiency was estimated, the cavitationally active regions were visualized using the sonochemiluminescence (SCL) method and bubble cluster formation inside the vessel was macroscopically observed using a high speed camera (HSC). In the viscosity range tested, the calorimetry results showed that the efficiency and continuous operation of the device depend on both the rated power and the horn tip diameter. The ratio between electrical and calorimetric power input remained consistently around 40 to 50% across the different configurations for water, but for the 123.2 mPas solution exhibited significant variation ranging from 40 to 85%. Moreover, the power density in the smaller reactor was found to be nearly double compared to the larger one. The SCL analysis showed multiple cavitationally active zones in all setups, and the zones intensity decreased considerably with increase of the solutions viscosity. The results for the cone tip were not conclusive, but can be used as the basis for further investigation. The current research highlights the importance of thoroughly understanding the impact of each design parameter, and of establishing characterization methodologies to assist in the future development of scaled-up, commercial applications. |
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Thesis |
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Place of Publication |
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Editor |
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Wos |
001218630800001 |
Publication Date |
2024-02-21 |
| 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 |
0255-2701 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
| Impact Factor |
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Times cited |
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Open Access |
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| Notes |
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Approved |
no |
| Call Number |
UA @ admin @ c:irua:206003 |
Serial |
9154 |
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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 |
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| Volume |
|
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 |
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| Corporate Author |
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Thesis |
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Place of Publication |
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Editor |
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Wos |
001159843800001 |
Publication Date |
2024-02-10 |
| 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 |
1616-301x |
ISBN |
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Additional Links |
UA library record; WoS full record |
| Impact Factor |
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Times cited |
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Open Access |
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| Notes |
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Approved |
no |
| Call Number |
UA @ admin @ c:irua:203812 |
Serial |
9161 |
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| Author |
Coulombier, M.; Baral, P.; Orekhov, A.; Dohmen, R.; Raskin, J.P.; Pardoen, T.; Cordier, P.; Idrissi, H. |
| Title |
On-chip very low strain rate rheology of amorphous olivine films |
Type |
A1 Journal article |
| Year |
2024 |
Publication |
Acta materialia |
Abbreviated Journal |
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| Volume |
266 |
Issue |
|
Pages |
119693-12 |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
| Abstract |
Recent observations made by the authors revealed the activation of stress induced amorphization and sliding at grain boundary in olivine [1], a mechanism which is expected to play a pivotal role in the viscosity drop at the lithosphere-asthenosphere boundary and the brittle -ductile transition in the lithospheric mantle. However, there is a lack of information in the literature regarding the intrinsic mechanical properties and the elementary deformation mechanisms of this material, especially at time scales relevant for geodynamics. In the present work, amorphous olivine films were obtained by pulsed laser deposition (PLD). The mechanical response including the rate dependent behavior are investigated using a tension -on -chip (TOC) method developed at UCLouvain allowing to perform creep/relaxation tests on thin films at extremely low strain rates. In the present work, strain rate down to 10-12 s- 1 was reached which is unique. High strain rate sensitivity of 0.054 is observed together with the activation of relaxation at the very early stage of deformation. Furthermore, digital image correlation (DIC), used for the first time on films deformed by TOC, reveals local strain heterogeneities. The relationship between such heterogeneities, the high strain rate sensitivity and the effect of the electron beam in the scanning electron microscope is discussed and compared to the literature. |
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| Corporate Author |
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Thesis |
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Place of Publication |
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Editor |
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Wos |
001170513400001 |
Publication Date |
2024-01-17 |
| 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 |
1359-6454 |
ISBN |
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Additional Links |
UA library record; WoS full record |
| Impact Factor |
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Times cited |
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Open Access |
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| Notes |
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Approved |
no |
| Call Number |
UA @ admin @ c:irua:204864 |
Serial |
9163 |
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| Author |
Joy, R.M.; Pobedinskas, P.; Bourgeois, E.; Chakraborty, T.; Goerlitz, J.; Herrmann, D.; Noel, C.; Heupel, J.; Jannis, D.; Gauquelin, N.; D'Haen, J.; Verbeeck, J.; Popov, C.; Houssiau, L.; Becher, C.; Nesladek, M.; Haenen, K. |
| Title |
Photoluminescence of germanium-vacancy centers in nanocrystalline diamond films : implications for quantum sensing applications |
Type |
A1 Journal article |
| Year |
2024 |
Publication |
ACS applied nano materials |
Abbreviated Journal |
|
| Volume |
7 |
Issue |
4 |
Pages |
3873-3884 |
| Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
| Abstract |
Point defects in diamond, promising candidates for nanoscale pressure- and temperature-sensing applications, are potentially scalable in polycrystalline diamond fabricated using the microwave plasma-enhanced chemical vapor deposition (MW PE CVD) technique. However, this approach introduces residual stress in the diamond films, leading to variations in the characteristic zero phonon line (ZPL) of the point defect in diamond. Here, we report the effect of residual stress on germanium-vacancy (GeV) centers in MW PE CVD nanocrystalline diamond (NCD) films fabricated using single crystal Ge as the substrate and solid dopant source. GeV ensemble formation indicated by the zero phonon line (ZPL) at similar to 602 nm is confirmed by room temperature (RT) photoluminescence (PL) measurements. PL mapping results show spatial nonuniformity in GeV formation along with other defects, including silicon-vacancy centers in the diamond films. The residual stress in NCD results in shifts in the PL peak positions. By estimating a stress shift coefficient of (2.9 +/- 0.9) nm/GPa, the GeV PL peak position in the NCD film is determined to be between 598.7 and 603.2 nm. A larger ground state splitting due to the strain on a GeV-incorporated NCD pillar at a low temperature (10 K) is also reported. We also report the observation of intense ZPLs at RT that in some cases could be related to low Ge concentration and the surrounding crystalline environment. In addition, we also observe thicker microcrystalline diamond (MCD) films delaminate from the Ge substrate due to film residual stress and graphitic phase at the diamond/Ge substrate interface (confirmed by electron energy loss spectroscopy). Using this approach, a free-standing color center incorporated MCD film with dimensions up to 1 x 1 cm(2) is fabricated. Qualitative analysis using time-of-flight secondary ion mass spectroscopy reveals the presence of impurities, including Ge and silicon, in the MCD film. Our experimental results will provide insights into the scalability of GeV fabrication using the MW PE CVD technique and effectively implement NCD-based nanoscale-sensing applications. |
| Address |
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| Corporate Author |
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Thesis |
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Place of Publication |
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Editor |
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Wos |
001164609600001 |
Publication Date |
2024-02-15 |
| 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 |
2574-0970 |
ISBN |
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Additional Links |
UA library record; WoS full record |
| Impact Factor |
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Times cited |
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Open Access |
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| Notes |
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Approved |
no |
| Call Number |
UA @ admin @ c:irua:204826 |
Serial |
9164 |
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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 |
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| Volume |
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Issue |
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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. |
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Additional Links |
UA library record |
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Open Access |
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Approved |
no |
| Call Number |
UA @ admin @ c:irua:206180 |
Serial |
9167 |
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| Author |
Poppe, R.; Roth, N.; Neder, R.B.; Palatinus, L.; Iversen, B.B.; Hadermann, J. |
| Title |
Refining short-range order parameters from the three-dimensional diffuse scattering in single-crystal electron diffraction data |
Type |
A1 Journal article |
| Year |
2024 |
Publication |
IUCrJ |
Abbreviated Journal |
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| Volume |
11 |
Issue |
1 |
Pages |
82-91 |
| Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
| Abstract |
Our study compares short-range order parameters refined from the diffuse scattering in single-crystal X-ray and single-crystal electron diffraction data. Nb0.84CoSb was chosen as a reference material. The correlations between neighbouring vacancies and the displacements of Sb and Co atoms were refined from the diffuse scattering using a Monte Carlo refinement in DISCUS. The difference between the Sb and Co displacements refined from the diffuse scattering and the Sb and Co displacements refined from the Bragg reflections in single-crystal X-ray diffraction data is 0.012 (7) angstrom for the refinement on diffuse scattering in single-crystal X-ray diffraction data and 0.03 (2) angstrom for the refinement on the diffuse scattering in single-crystal electron diffraction data. As electron diffraction requires much smaller crystals than X-ray diffraction, this opens up the possibility of refining short-range order parameters in many technologically relevant materials for which no crystals large enough for single-crystal X-ray diffraction are available. |
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Thesis |
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Place of Publication |
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Editor |
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Wos |
001168018300012 |
Publication Date |
2023-12-14 |
| 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 |
2052-2525 |
ISBN |
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Additional Links |
UA library record; WoS full record |
| Impact Factor |
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Times cited |
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Open Access |
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| Notes |
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Approved |
no |
| Call Number |
UA @ admin @ c:irua:205513 |
Serial |
9170 |
| Permanent link to this record |
